Relevant bibliographies by topics / High Frequency Current Injection

Academic literature on the topic 'High Frequency Current Injection'

Author: Grafiati
Published: 10 March 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'High Frequency Current Injection.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "High Frequency Current Injection"

1

Harke, M. C., J. M. Guerrero, M. W. Degner, F. Briz, and R. D. Lorenz. "Current Measurement Gain Tuning Using High-Frequency Signal Injection." IEEE Transactions on Industry Applications 44, no. 5 (September 2008): 1578–86. http://dx.doi.org/10.1109/tia.2008.2002170.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Liu, Zhao, Wang, Huang, and Shi. "Compatibility Issues with Irregular Current Injection Islanding Detection Methods and a Solution." Energies 12, no. 8 (April 17, 2019): 1467. http://dx.doi.org/10.3390/en12081467.

Full text
Abstract:
Islanding detection methods, based on injecting high-/low-frequency currents or negative sequence fundamental frequency currents and observing the resultant responses, are collectively referred to as irregular current injection methods in this paper. In multi-distributed generation (DG) operation, if there is no restriction to the phase of injected irregular currents, the currents at the same frequency may cancel each other out, and then their convergent current may be too small to cause a detectable response, for which reason islanding detection will be severely affected. Accordingly, this paper raises a compatibility issue, which requires the phase difference between any two injected irregular currents to be within a certain interval. In response to this issue, a solution is proposed. According to this solution, the terminal voltage of DG units is referenced to conduct irregular currents injection, and only certain high-frequency currents are used as injected currents. If this solution is adopted by as many manufacturers as possible, the effect and reliability of such methods will be greatly improved.
APA, Harvard, Vancouver, ISO, and other styles
3

Kim, Dongouk, Yong-Cheol Kwon, Seung-Ki Sul, Jang-Hwan Kim, and Rae-Sung Yu. "Suppression of Injection Voltage Disturbance for High-Frequency Square-Wave Injection Sensorless Drive With Regulation of Induced High-Frequency Current Ripple." IEEE Transactions on Industry Applications 52, no. 1 (January 2016): 302–12. http://dx.doi.org/10.1109/tia.2015.2478887.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Okano, Toshiki, Takuya Mitani, Akihiro Suwa, Yoshihiko Matsui, Masayuki Sakaki, Akiko Kumada, and Kunihiko Hidaka. "DC Interruption Characteristics of VCB by Injection of High Frequency Current." IEEJ Transactions on Power and Energy 138, no. 6 (June 1, 2018): 535–36. http://dx.doi.org/10.1541/ieejpes.138.535.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Bhadra, D. K., and C. Chu. "RF current drive with magnetic helicity injection." Journal of Plasma Physics 33, no. 2 (April 1985): 257–64. http://dx.doi.org/10.1017/s002237780000249x.

Full text
Abstract:
External injection of magnetic helicity into a plasma may be possible through the introduction of appropriately polarized electromagnetic waves. A concept of steady-state current-drive is presented, based on the validity of conservation of helicity (appropriately defined for finite frequency processes). It is shown that such external injection of helicity can maintain a steady-state current by compensating the volt-seconds consumed through plasma resistivity. Such a mechanism, if experimentally successful, is particularly interesting at high densities because the efficiency of the process does not depend on plasma density, as opposed to other radio-frequency current-drive techniques.
APA, Harvard, Vancouver, ISO, and other styles
6

Li, Ke, Tianfu Sun, Fucheng Jiang, Wei Feng, and Huiyun Li. "MTPA Control for IPMSM Drives Based on Pseudorandom Frequency-Switching Sinusoidal Signal Injection." Machines 10, no. 4 (March 25, 2022): 231. http://dx.doi.org/10.3390/machines10040231.

Full text
Abstract:
Among various maximum torque per ampere (MTPA) control schemes for interior permanent magnet synchronous motor (IPMSM) drives, the signal-injection-based methods exhibit relatively high overall performance due to their high control accuracy and satisfactory dynamic performance. However, the high current spectrum peaks induced by the fixed-frequency signal injection may cause electromagnetic interference and even audible noise problems in applications, such as electric vehicles, vessels, and aircraft. To address this problem, an MTPA control method using pseudorandom frequency-switching sinusoidal signal injection is proposed in this paper. The sinusoidal signals with two different frequencies are randomly injected into the d- and q-axis currents and the MTPA points can be tracked according to the resultant system response. In this way, a high-performance MTPA control can be achieved regardless of motor parameter variations. Since the injection frequency of the proposed method varies randomly, the induced harmonic components in phase currents no longer concentrate at certain frequencies, and the current spectrum peaks caused by signal injection can be reduced accordingly. The experimental results demonstrate the validity of the presented method.
APA, Harvard, Vancouver, ISO, and other styles
7

Wang, Jian Min. "Performance of Pulsating High-Frequency Current Injection Based Sensorless Control of PMSM." Applied Mechanics and Materials 347-350 (August 2013): 610–16. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.610.

Full text
Abstract:
In the paper the principle and performances of the pulsating current injection based sensorless control of permanent magnet synchronous motor (PMSM) are analyzed theoretically and investigated by simulations. In the analyses, the effects of the speed EMF terms and the deviation between the actual d-axis high-frequency current and the command, which results from the limited gain and bandwidth of the current control loop, are all taken into account. It is shown that the pulsating current injection method can achieve stable position estimation in a wide speed range. But appreciable position errors will result at high speeds due to the cross-coupling effects of the speed EMFs and the tracking error between the actual and command carrier current. In order to improve the performance, a modified scheme is proposed. Its validity is confirmed by simulations.
APA, Harvard, Vancouver, ISO, and other styles
8

Seog-Joo Kang, Jang-Mok Kim, and Seung-Ki Sul. "Position sensorless control of synchronous reluctance motor using high frequency current injection." IEEE Transactions on Energy Conversion 14, no. 4 (1999): 1271–75. http://dx.doi.org/10.1109/60.815058.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Reigosa, David Diaz, Daniel Fernandez, Hideo Yoshida, Takashi Kato, and Fernando Briz. "Permanent-Magnet Temperature Estimation in PMSMs Using Pulsating High-Frequency Current Injection." IEEE Transactions on Industry Applications 51, no. 4 (July 2015): 3159–68. http://dx.doi.org/10.1109/tia.2015.2404922.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Cross, A. M., and A. J. Forsyth. "A high-power-factor, three-phase isolated AC-DC converter using high-frequency current injection." IEEE Transactions on Power Electronics 18, no. 4 (July 2003): 1012–19. http://dx.doi.org/10.1109/tpel.2003.813781.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "High Frequency Current Injection"

1

Panofski, Eva. "Beam Dynamics and Limits for High Brightness, High Average Current Superconducting Radiofrequency (SRF) Photoinjectors." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/19962.

Full text
Abstract:
Zukünftige Beschleunigerprojekte und Nutzerexperimente erfordern für ihren Betrieb einen hochbrillanten Elektronenstrahl mit hohem mittlerem Strom. Eine Elektronenquelle mit dem Potential die Anforderungen erfüllen, ist ein supraleitender Hochfrequenz (SHF) Photoinjektor im Dauerstrichbetrieb. Die Strahldynamik eines solchen Photoinjektor Systems bestimmt die maximal zu erreichende Strahlbrillanz und wird ihrerseits von den Design und Betriebsparametern des Photoinjektors beeinflusst. Ziel ist immer die entscheidenden Design- und Betriebsparameter der Elektronenquelle hinsichtlich einer maximalen Strahlbrillanz zu wählen. Diese Aufgabe verlangt ein detailliertes Verständnis der Strahldynamik-Prozesse. Ferner ist es notwendig, eine Optimierung des Photoinjektors als Ganzes, mit dem Ziel einer maximalen Strahlqualität bei hohem mittlerem Strom, vorzunehmen. Dieses ermöglicht auch, die physikalischen Grenzen eines gegebenen Designs zu ermitteln und im Betrieb vollständig auszunutzen. Diese Doktorarbeit befasst sich mit der Strahldynamik in einem SHF Photoinjektor, unter Berücksichtigung interner Raumladungseffekte. Die Erkenntnisse zur Strahldynamik werden für die Entwicklung eines Optimierungsprogramms verwendet, um die Leistung des Injektors hinsichtlich der Strahlbrillanz zu verbessern. Die entwickelte Methode basiert auf Pareto-Optimierung mehrerer Zielfunktionen, unter Verwendung eines generischen Algorithmus. Das zentrale Ergebnis dieser Arbeit umfasst ein universelles Optimierungsprogramm, das für Photoinjektoren unabhängig von ihrem Design und Anwendungsgebiet genutzt werden kann. Für den Betrieb mit hoher Strahlbrillanz ist es möglich aus den erhaltenen Pareto-optimalen Lösungen einen stabilen Satz an Einstellwerten für den Photoinjektor zu extrahieren. Durch die allgemeine Optimierungsstrategie lässt sich das entwickelte Programm auch für andere Beschleunigerabschnitte, oder die Optimierung einer ganzen Anlage mit erweiterter Zielsetzung anpassen.
An increasing number of future accelerator projects, light sources and user experiments require high brightness, high average current electron beams for operation. Superconducting radio-frequency (SRF) photoinjectors running in continuous-wave (cw) mode hold the potential to serve as an electron source that generates electron beams of high brightness. Different operation and design parameters of the SRF photoinjector impact the beam dynamics and, thus, the beam brightness. Therefore, an in-depth understanding of the beam dynamics processes in an SRF photoinjector and the dependency of the beam dynamics on the photoinjector set parameters is crucial. A high brightness beam operation requires a global optimization of the SRF photoinjector that allows to find suitable photoinjector settings and to figure out and extend the physical performance limits of the investigated injector design. The dissertation at hand offers a detailed analysis of the beam dynamics in an SRF photoinjector regarding internal space charge effects. Furthermore, the impact of the photoinjector elements on the electron beam is discussed. The lessons learned from this theoretical view are implemented in the development of an optimization tool to achieve a high brightness performance. A universal multi-objective optimization program based on a generic algorithm was developed to extract stable, optimum gun parameter from Pareto-optimum solutions. This universal tool is able to optimize and find the physical performance limit of any (S)RF photoinjector independent from the individual application of the electron source (energy recovery linac, free electron laser, ultra-fast electron diffraction). This thesis thereby verifies and complements existing theoretical considerations regarding photoinjector-beam interactions. The global optimization strategy can be introduced to variable optimization objectives as well as it can be extended to an optimization of further parts of the accelerator facility.
APA, Harvard, Vancouver, ISO, and other styles
2

Zhou, Jinghai. "High Frequency, High Current Density Voltage Regulators." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27268.

Full text
Abstract:
As a very special DC-DC converter, VRM (Voltage Regulator Module) design must follow the fast-developing trend of microprocessors. The design challenges are the high current, high di/dt, and stringent load-line requirement. When the energy is transferred from the input of a VRM, through the VRM, then through the power delivery path to the processor, it needs sufficient capacitors to relay this energy. The capacitorsâ number appears to be unrealistically large if we follow todayâ s approach for the future processors. High frequency VRM with high control bandwidth can solve this problem, however, the degradation of efficiency makes the conventional buck converter and the hard-switching isolated topologies incapable of operating at higher frequency. The research goal is to develop novel means that can help a high-output- current VRM run efficiently at high frequency. A novel Complementary Controlled Bridge (CCB) self-driven concept is proposed. With the proposed self-driven scheme, the combination of the ZVS technique and the self-driven technique recycles the gate driving energy by making use of the input capacitor of the secondary- side synchronous rectifier (SR) as the snubber capacitor of the primary-side switches. Compared to the external driver, the proposed converter can save driving loss and synchronous rectifier body diode conduction loss. Additionally, compared to the existing level-shifted self-driven scheme for bridge-type symmetrical topologies, its gate signal ringing is small and suitable for high-frequency applications. Although the CCB self-driven VRM reduces the switching frequency-related losses significantly, the conduction loss is still high. Inspired by the current-doubler concept, a novel ZVS current-tripler DC-DC converter is proposed in this work. By utilizing more SR devices to share the current during the freewheeling period, the SR conduction loss is reduced. The current-tripler DC-DC converter has a delta/delta connected transformer that can be implemented with integrated magnetics. The transformer then becomes an integrated magnetic with distributed windings, which is preferred in high current applications. The current-tripler DC-DC converter in fact meets the requirements for the CCB self-driven scheme. The two concepts are then combined with an integrated gate drive transformer. The proposed CCB self-driven concept and current-tripler concept can both be applied to the 12V non-isolated VRMs. The proposed topology is basically a buck-derived soft-switching topology with duty cycle extension and SR device self-driven capabilities. Because there is no isolation requirement, the SR gate driving becomes so simple that the voltage at the complementary controlled bridge can be used to directly drive the SR gate. Both the gate driving loss and the SR body diode conduction loss are reduced. The proposed circuit achieves similar overall efficiency to a conventional 300kHz buck converter running at 1MHz. All the circuits proposed in this dissertation can use coupling inductors to improve both the steady-state efficiency and dynamic performances. The essence of the coupling inductors concept is to provide different equivalent inductances for the steady state and the transient. Moreover, when a current loop becomes necessary to achieve proper current sharing among phases, the current loop sample hold effect will make it difficult to push the bandwidth. The sample hold effect is alleviated by the coupling inductors concept. A small-signal model is proposed to study the system dynamic performance difference with different coupling inductor designs. As the verification, the coupling concept is applied to the 12V non-isolated CCB self-driven VRM and the bandwidth as high as one third of the switching frequency is achieved, which means a significant output capacitor reduction.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
3

Hayatleh, Khaled. "High frequency current-mode precision rectifiers." Thesis, Oxford Brookes University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308928.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Reusch, David Clayton. "High Frequency, High Current Integrated Magnetics Design and Analysis." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35420.

Full text
Abstract:
The use of computers in the modern world has become prevalent in all aspects of life. The size of these machines has decreased dramatically while the capability has increased exponentially. A special DC-DC converter called a VRM (Voltage Regulator Module) is used to power these machines. The VRM faces the task of supplying high current and high di/dt to the microprocessor while maintaining a tight load regulation. As computers have advanced, so have the VRM's used to power them. Increasing the current and di/dt of the VRM to keep up with the increasing demands of the microprocessor does not come without a cost. To provide the increased di/dt, the VRM must use a higher number of capacitors to supply the transient energy. This is an undesirable solution because of the increased cost and real estate demands this would lead to in the future. Another solution to this problem is to increase the switching frequency and control bandwidth of the VRM. As the switching frequency increases the VRM is faced with efficiency and thermal problems. The current buck topologies suffer large drops in efficiency as the frequency increases from high switching losses.

Resonant or soft switching topologies can provide a relief from the high switching loss for high frequency power conversion. One disadvantage of the resonant schemes is the increased conduction losses produced by the circulating energy required to produce soft switching. As the frequency rises, the additional conduction loss in the resonant schemes can be smaller than the switching loss encountered in the hard switched buck. The topology studied in this work is the 12V non-isolated ZVS self-driven presented in [1]. This scheme offered an increased efficiency over the state of the art industry design and also increased the switching frequency for capacitor reduction. The goal of this research was to study this topology and improve the magnetic design to decrease the cost while maintaining the superior performance.

The magnetics used in resonant converters are very important to the success of the design. Often, the leakage inductance of the magnetics is used to control the ZVS or ZCS switching operation. This work presents a new improved magnetic solution for use in the 12V non-isolated ZVS self-driven scheme which increases circuit operation, flexibility, and production feasibility. The improved magnetic structure is simulated using 3D FEA verification and verified in hardware design.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles
5

Mahattanakul, Jirayuth. "High frequency, low distortion current-mode filters." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300970.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Worapishet, Apisak. "High frequency low power switched-current techniques." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392911.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Egnor, Dianne Elizabeth. "High-frequency acoustic tomography in a high-current coastal environment." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/88350.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Su, Yipeng. "High Frequency, High Current 3D Integrated Point-of-Load Module." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51248.

Full text
Abstract:
Point-of-load (POL) converters have been used extensively in IT products. Today, almost every microprocessor is powered by a multi-phase POL converter with high output current, which is also known as voltage regulator (VR). In the state-of-the-art VRs, the circuits are mostly constructed with discrete components and situated on the motherboard, where it can occupy more than 1/3 of the footprint of the motherboard. A compact POL is desirable to save precious space on motherboards to be used for some other critical functionalities. Recently, industry has released many modularized POL converters, in which the bulky inductor is integrated with the active components to increase the power density. This concept has been demonstrated at current levels less than 5A and power density around 600-1000W/in3. This might address the needs of small hand-held equipment such as smart phones, but it is far from meeting the needs for the applications such as laptops, desktops and servers, where tens and hundreds of amperes are needed. A 3D integrated POL module with an output current of tens of ampere has been successfully demonstrated at the Center for Power Electronic Systems (CPES), Virginia Tech. In this structure, the inductor is elaborated with low temperature co-fire ceramic (LTCC) ferrite, as a substrate where the active components are placed. The lateral flux inductor is proposed to achieve both a low profile and high power density. Generally, the size of the inductor can be continuously shrunk by raising the switching frequency. The emerging gallium-nitride (GaN) power devices enable the creation and use of a multi-MHz, high efficiency POL converter. This dissertation firstly explores the LTCC inductor substrate design in the multi-MHz range for a high-current POL module with GaN devices. The impacts of different frequencies and different LTCC ferrite materials on the inductor are also discussed. Thanks to the DC flux cancellation effect, the inverse coupled inductor further improves the power density of a 20A, 5MHz two-phase POL module to more than 1kW/in3. An FEA simulation model is developed to study the core loss of the lateral flux coupled inductor, which shows the inverse coupling is also beneficial for core loss reduction. The ceramic-based 3D integrated POL module, however, is not widely adopted in industrial products because of the relatively high cost of the LTCC ferrite material and complicated manufacturing process. To solve that problem, a printed circuit board (PCB) inductor substrate with embedded alloy flake composite core is proposed. The layerwise magnetic core is laminated into a multi-layer PCB, and the winding of the inductor then is formed by the copper layers and conventional PCB vias. As a demonstration of system integration, a 20A, 1.5MHz integrated POL module is designed and fabricated based on a 4-layer PCB with embedded flake core, which realizes more than 85% efficiency and 600W/in3 power density. The application of standardized PCB processes reduces the cost for manufacturing the integrated modules due to the easy automation and the low temperature manufacturing process. Combining the PCB-embedded coupled inductor substrate and advanced control strategy, the two-phase 40A POL modules are elaborated as a complete integrated laptop VR solution. The coupled inductor structure is slightly modified to improve its transient performance. The nonlinearity of the inductance is controlled by adding either air slots or low permeability magnetic slots into the leakage flux path of the coupled inductor. Then the leakage flux, which determines the transient response of the coupled inductor, can be well controlled. If we directly replace the discrete VR solution with the proposed integrated modules, more than 50% of the footprint on the motherboard can be saved. Although the benefits of the lateral flux inductor have been validated in terms of its high power density and low profile, the planar core is excited under very non-uniform flux. Some parts of the core are even pushed into the saturation region, which totally goes against the conventional sense of magnetic design. The final part of this dissertation focuses on evaluating the performance of the planar core with variable flux. The counterbalance between DC flux and AC flux is revealed, with which the AC flux and the core loss density are automatically limited in the saturated core. The saturation is essentially no longer detrimental in this special structure. Compared with the conventional uniform flux design, the variable flux structure extends the operating point into the saturation region, which gives better utilization of the core. In addition, the planar core with variable flux also provides better thermal management and more core loss reduction under light load. As conclusions, this research first challenges the conventional magnetic design rules, which always assumes uniform flux. The unique characteristics and benefits of the variable flux core are proved. As an example of taking advantages of the lateral flux inductor, the PCB integrated POL modules are proposed and demonstrated as a high-density VR solution. The integrated modules are cost-effective and ready to be commercialized, which could enable the next technological innovation for the whole computing and telecom industry.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
9

PIDUTTI, ALBINO. "High Frequency Buck Converter for Automotive Current Source Applications." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2023. https://hdl.handle.net/10281/404716.

Full text
Abstract:
Il presente lavoro e’ stato svolto in cooperation tra l’infineon e l’Universita’ Milano Bicocca, l’obbiettivo e’ sviluppare il cuore di un convertitore DC-DC Buck Converter ad alta frequenza di commutazione. I convertitori a commutazione offrono un modo semplice ed efficiente per alimentare carichi elettronici. Inoltre, gli alimentatori DC-DC consentono di soddisfare efficacemente molti requisiti di sicurezza delle automobili moderne. Ad esempio è assolutamente necessario che le luci di emergenza, i fari e le luci dei freni mantengano la loro funzionalità in tutte le condizioni, soprattutto durante l'avviamento a freddo, quando la tensione della batteria raggiunge valori molto bassi (anche 4V). Ma in certe condizioni esperimentano tensioni anche superiori ai 30V. Gli alimentatori DC-DC ben si adattano ad ampie e repentine variazioni della tensione di alimentazione, inoltre alla loro relativa semplicità uniscono un’alta efficienza, valori superiori al 90%. Aumentando la frequenza di commutazione si riducono linearmente le dimensioni dei componenti reattivi, permettendo schede PCB più piccole e conseguentemente costi ridotti. Le tecnologie BCD consentono di integrare su un singolo chip (SOC - System On Chip) transistor di potenza, logica di controllo e diagnostica. In questa ricerca sono stati sviluppati tre convertitori Buck che lavorano a tre diverse frequenze 1MHz, 4MHz e 10MHz con una corrente di uscita di 3A. Tra i Buck converter disponibili sul mercato solo quelli più performanti hanno frequenze di commutazione di 2,0-2,5 MHz e correnti nel carico di 2-2,5 A. Poiché l'obiettivo di 10MHz con una corrente di carico di 3A è molto aggressivo, è stata adottata un'architettura del convertitore Buck che minimizza il tempo di transizione dei segnali elettrici ed è stato necessario sviluppare una nuova topologia di driver molto più veloce e potente delle soluzioni adottate finora (patent pending). Al momento in cui scriviamo, i dispositivi da 1 MHz e 4 MHz sono in fase di diffusione. L'uscita dei wafer è prevista per febbraio 2023. Il terzo convertitore Buck (10 MHz) e’ in attesa di diffusione. Durante questo lavoro di dottorato sono state presentate quattro proposte di brevetto.
This work was carried out in cooperation between Infineon and the University of Milan Bicocca, the aim being to develop the core of a DC-DC Buck Converter with a high switching frequency. Switching converters offer a simple and efficient way to power electronic loads. In addition, DC-DC power supplies make it possible to effectively meet many safety requirements of modern automobiles. For example, it is absolutely necessary that emergency lights, headlights and brake lights maintain their functionality under all conditions, especially during cold starting, when the battery voltage reaches very low values (even 4V). But under certain conditions they experience voltages even above 30V. DC-DC power supplies are well suited to large and sudden variations in supply voltage, and in addition to their relative simplicity they combine high efficiency, values of over 90%. Increasing the switching frequency reduces the size of reactive components linearly, allowing smaller PCBs and consequently lower costs. BCD technologies allow power transistors, control logic and diagnostics to be integrated on a single chip (SOC - System On Chip). In this research, three Buck converters were developed that operate at three different frequencies 1MHz, 4MHz and 10MHz with an output current of 3A. Of the buck converters available on the market, only the best performing ones have switching frequencies of 2.0-2.5MHz and load currents of 2-2.5A. Since the target of 10MHz with a load current of 3A is very aggressive, a Buck converter architecture was adopted that minimises the transition time of electrical signals, and a new driver topology had to be developed that is much faster and more powerful than the solutions adopted so far (patent pending). At the time of writing, 1 MHz and 4 MHz devices are being deployed. The wafers are scheduled for release in February 2023. The third Buck converter (10 MHz) is pending deployment. Four patent proposals were submitted during this doctoral work.
APA, Harvard, Vancouver, ISO, and other styles
10

Liu, Kwang-Hwa. "High-frequency quasi-resonant converter techniques." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/74737.

Full text
Abstract:
Two waveform-shaping techniques to reduce or eliminate the switching stresses and switching losses in switching-mode power conversion circuits are developed: the zero-current switching technique and the zero-voltage switching technique. Based on these two techniques two new families of quasi-resonant converters are derived. Since the stresses on semiconductor switching devices are significantly alleviated, these quasi-resonant (QRC) converters are suitable for high-frequency operations with much improved performances and equipment power density. Employing the duality principle, the duality relationship between these two families of quasi-resonant converters are derived. The establishment of the duality relationship provides a framework allowing the knowledge obtained from one converter family to be readily transferred to the other. Further topological refinements are derived through the utilization of parasitic elements in the devices and the circuit. In particular, the two most significant parasitic elements, the leakage inductance of the transformer and the junction capacitances of the semiconductor switch, are incorporated as part of the resonant-tank circuit required by these quasi-resonant converters. Consequently, the detrimental effects due to these parasitic elements are eliminated, and the converters can be operated at very high frequencies.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "High Frequency Current Injection"

1

Hayatleh, Khaled. High frequency current-mode precision rectifiers. Oxford: Oxford Brookes University, 1996.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Skinner, A. J. Four quadrant inverter technologies for high frequency UPS. Leatherhead, Surrey, England: ERA Technology, 1992.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

International, High Frequency Power Conversion Conference (2nd 1987 Washington D. C. ). 1987 High Frequency Power Conversion International, Washington, D.C. Ventura, Calif: Intertec Communications, 1987.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Balciūnas, Povilas. Development and investigation of high frequency voltage-current power converters, theory and application: Summary. Kaunas: Republic of Lithuania, Kaunas University of Technology, 1994.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

International High Frequency Power Conversion Conference. (3rd 1988 San Diego (Calif.)). Technical papers of the third International High Frequency Power Conversion 1988 Conference, May 1-5, 1988, San Diego, California. Ventura: Intertec Communications, 1988.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Irfan, Alan, University of Wisconsin--Madison, and Lewis Research Center, eds. System and component design and test of a 10 HP, 18,000 RPM dynamometer utilizing a high frequency AC voltage link. Madison, WI: University of Wisconsin, Dept. of Electrical and Computer Engineering, 1991.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Prohorov, Viktor. Semiconductor converters of electrical energy. ru: INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1019082.

Full text
Abstract:
The textbook considers the need, principles and methods of mutual conversion of parameters of electric energy at DC and AC for stationary and Autonomous objects. Features of operation of power electronics elements in specific conditions of their continuous high-frequency switching are described. Low-current control systems that provide the necessary logic for the operation of Executive power devices of converters are considered. A large number of specific practical electrical diagrams of electric energy converters are given. It is intended for students studying in the direction of 13.03.02 "electric power and electrical engineering". It can be useful for graduate students and specialists involved in the development and operation of electric power converters.
APA, Harvard, Vancouver, ISO, and other styles
8

Luszcz, Jaroslaw. High Frequency Conducted Emission in AC Motor Drives Fed By Frequency Converters: Sources and Propagation Paths. Wiley-IEEE Press, 2018.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Luszcz, Jaroslaw. High Frequency Conducted Emission in AC Motor Drives Fed by Frequency Converters: Sources and Propagation Paths. Wiley & Sons, Limited, John, 2018.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Maksimovic, Dragan, Luca Corradini, Paolo Mattavelli, and Regan Zane. Digital Control of High-Frequency Switched-Mode Power Converters. Wiley & Sons, Limited, John, 2015.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "High Frequency Current Injection"

1

Dijkhuis, J. I. "High-Frequency Phonon Injection." In Phonon Scattering in Condensed Matter V, 320–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82912-3_92.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Bunnell, J. Bert. "High-Frequency Ventilation of Infants." In Current Perinatology, 172–201. New York, NY: Springer New York, 1990. http://dx.doi.org/10.1007/978-1-4612-3380-0_12.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Hillmann, Susanne, Martin H. Schulze, and Henning Heuer. "High-Frequency Eddy Current Techniques." In Handbook of Advanced Non-Destructive Evaluation, 1–28. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-30050-4_49-1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Hillmann, Susanne, Martin H. Schulze, and Henning Heuer. "High-Frequency Eddy Current Techniques." In Handbook of Advanced Nondestructive Evaluation, 729–56. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-26553-7_49.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Sojka, Antonín, Matúš Šedivý, Oleksii Laguta, Andriy Marko, Vinicius T. Santana, and Petr Neugebauer. "High-frequency EPR: current state and perspectives." In Electron Paramagnetic Resonance, 214–52. Cambridge: Royal Society of Chemistry, 2020. http://dx.doi.org/10.1039/9781839162534-00214.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Armbruster, Wolfgang, Justin S. Hardi, and Michael Oschwald. "Experimental Investigation of Injection-Coupled High-Frequency Combustion Instabilities." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 249–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53847-7_16.

Full text
Abstract:
Abstract Self-excited high-frequency combustion instabilities were investigated in a 42-injector cryogenic rocket combustor under representative conditions. In previous research it was found that the instabilities are connected to acoustic resonance of the shear-coaxial injectors. In order to gain a better understanding of the flame dynamics during instabilities, an optical access window was realised in the research combustor. This allowed 2D visualisation of supercritical flame response to acoustics under conditions similar to those found in European launcher engines. Through the window, high-speed imaging of the flame was conducted. Dynamic Mode Decomposition was applied to analyse the flame dynamics at specific frequencies, and was able to isolate the flame response to injector or combustion chamber acoustic modes. The flame response at the eigenfrequencies of the oxygen injectors showed symmetric and longitudinal wave-like structures on the dense oxygen core. With the gained understanding of the BKD coupling mechanism it was possible to derive LOX injector geometry changes in order to reduce the risks of injection-coupled instabilities for future cryogenic rocket engines.
APA, Harvard, Vancouver, ISO, and other styles
7

Zhang, Jun-an, Ruitao Zhang, and Guangjun Li. "High Speed Current Steering D/A Converter." In High-Speed and High-Performance Direct Digital Frequency Synthesizer Design, 67–107. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7266-8_3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Lunkenheimer, P. P., W. F. Whimster, N. Stroh, J. Theissen, G. Frieling, and H. Van Aken. "High-frequency Ventilation: A Step Towards “Compliance-Independent” Ventilation." In Current Concepts in Critical Care, 157–66. London: Springer London, 1988. http://dx.doi.org/10.1007/978-1-4471-1443-7_11.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Vélez, Adolfo, and Hans-Walter Glock. "Superconducting Radio-Frequency for High-Current CW Applications." In Synchrotron Light Sources and Free-Electron Lasers, 1–20. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-04507-8_59-1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Vélez, Adolfo, and Hans-Walter Glock. "Superconducting Radio-Frequency for High-Current CW Applications." In Synchrotron Light Sources and Free-Electron Lasers, 581–601. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23201-6_59.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "High Frequency Current Injection"

1

Knop, A., and F. W. Fuchs. "High frequency grid impedance analysis by current injection." In IECON 2009 - 35th Annual Conference of IEEE Industrial Electronics (IECON). IEEE, 2009. http://dx.doi.org/10.1109/iecon.2009.5414978.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Harke, Michael C., Juan M. Guerrero, Michael W. Degner, Fernando Briz, and Robert D. Lorenz. "Current Measurement Gain Tuning Using High Frequency Signal Injection." In 2007 IEEE Industry Applications Annual Meeting. IEEE, 2007. http://dx.doi.org/10.1109/07ias.2007.311.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Harke, Michael C., Juan M. Guerrero, Michael W. Degner, Fernando Briz, and Robert D. Lorenz. "Current Measurement Gain Tuning Using High Frequency Signal Injection." In 2007 IEEE Industry Applications Annual Meeting. IEEE, 2007. http://dx.doi.org/10.1109/ias.2007.311.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Liu, Tao, Changkai Wang, YuSheng Hu, Ziqiang Ye, Chengbao Zhong, and Gerd Griepentrog. "Offline Inductance Identification of PMSM using High Frequency Current Signal Injection." In 2019 22nd International Conference on Electrical Machines and Systems (ICEMS). IEEE, 2019. http://dx.doi.org/10.1109/icems.2019.8922168.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Dongouk Kim, Yong-Cheol Kwon, Seung-Ki Sul, Jang-Hwan Kim, and Rae-Sung Yu. "Suppression of injection voltage disturbance for High Frequency square-wave injection sensorless drive with regulation of induced High Frequency current ripple." In 2014 International Power Electronics Conference (IPEC-Hiroshima 2014 ECCE-ASIA). IEEE, 2014. http://dx.doi.org/10.1109/ipec.2014.6869698.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Valle, A. "High frequency current modulation of high order transverse modes in vertical-cavity surface emitting lasers." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.ctui47.

Full text
Abstract:
Weakly index guided vertical cavity surface emitting lasers (VCSELs) are analyzed in the multi-transverse mode regime. An efficient dynamical model is developed that takes into account all the transverse modes (LP mn ) supported by the waveguide. Mode partition noise in a current modulated VCSEL is studied taking into account the azimuthal degree of freedom. Different transverse modes can be excited with a probability that is numerically calculated. For high injection currents modes that are not favoured in the steady state can be the ones excited with higher probability. The excitation probability is similar for azimuthally orthogonal modes. This symmetry can be broken by selecting a particular high order transverse mode by using azimuthal dependent current profiling: injection is performed where the mode has appreciable power. This selection can be achieved over current ranges larger than ten times the threshold current. The radial range of injection current to obtain this selection is shown to be wide.
APA, Harvard, Vancouver, ISO, and other styles
7

Reigosa, David, Daniel Fernandez, Hideo Yoshida, Takashi Kato, and Fernando Briz. "Permanent magnet temperature estimation in PMSMs using pulsating high frequency current injection." In 2014 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2014. http://dx.doi.org/10.1109/ecce.2014.6954114.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Wang, Jianmin. "Performance of Pulsating High-Frequency Current Injection Based Sensorless Control of PMSM." In 2nd International Symposium on Computer, Communication, Control and Automation. Paris, France: Atlantis Press, 2013. http://dx.doi.org/10.2991/isccca.2013.41.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Xu, Zheng, Jianzhong Zhang, Yaqian Zhang, and Jin Zhao. "Winding condition monitoring for inverter-fed PMSM using high-frequency current injection." In 2020 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2020. http://dx.doi.org/10.1109/ecce44975.2020.9235726.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Xiao, Huiwen, Feng Zhao, Haibo Wang, Wei Huang, and Fei Xu. "Analysis of high frequency current at the sampling instant of SPMSM Based on High Frequency signal Injection method." In 2019 IEEE 3rd International Electrical and Energy Conference (CIEEC). IEEE, 2019. http://dx.doi.org/10.1109/cieec47146.2019.cieec-2019202.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "High Frequency Current Injection"

1

A.A. Litvak, Y. Raitses, and N.J. Fisch. High-frequency Probing Diagnostic for Hall Current Plasma Thrusters. Office of Scientific and Technical Information (OSTI), October 2001. http://dx.doi.org/10.2172/788452.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Cernosek, R. W. High frequency current sensors using the Faraday effect in optical fibers. Office of Scientific and Technical Information (OSTI), September 1994. http://dx.doi.org/10.2172/10190503.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Rubio, Anna, Emma Reyes, Carlo Mantovani, Lorenzo Corgnati, Pablo Lorente, Lohitzune Solabarrieta, Julien Mader, et al. European High Frequency Radar network governance. EuroSea, May 2021. http://dx.doi.org/10.3289/eurosea_d3.4.

Full text
Abstract:
This report describes the governance of the European HF radar network including: the landscape of the Ocean observation networks and infrastructures, the role and links between operators of observational systems and stakeholders, the role and activities of the EuroGOOS HF radar Task Team in building a sound community strategy, the roadmap of the community with current achievements and future work lines.
APA, Harvard, Vancouver, ISO, and other styles
4

Harold Schock, Farhad Jaberi, Ahmed Naguib, Guoming Zhu, and David Hung. High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback. Office of Scientific and Technical Information (OSTI), December 2007. http://dx.doi.org/10.2172/967307.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Moskalenko, O. L., E. V. Derevyannykh, N. A. Balashova, and R. A. Yaskevich. DEPRESSIVE DISORDERS AMONG STUDENTS OF MEDICAL HIGHER EDUCATIONAL INSTITUTIONS. Science and Innovation Center Publishing House, 2021. http://dx.doi.org/10.12731/2658-4034-2021-12-4-2-382-390.

Full text
Abstract:
The article presents a review of the literature on the current problem of medicine-depressive disorders among medical students. The need to study the problem of depressive disorders among students of medical higher educational institutions is due to their high frequency and negative impact on the quality of life of students.
APA, Harvard, Vancouver, ISO, and other styles
6

Tait, Emma, Pia Ruisi-Besares, Matthias Sirch, Alyx Belisle, Jennifer Pontius, and Elissa Schuett. Technical Report: Monitoring and Communicating Changes in Disturbance Regimes (Version 1.0). Forest Ecosystem Monitoring Cooperative, October 2021. http://dx.doi.org/10.18125/cc0a0l.

Full text
Abstract:
Shifts in disturbance patterns across the Northeast are of increasing concern as the climate continues to change. In particular, changes in patterns of frequency, severity and extent of disturbance event may have detrimental cascading impacts on forest ecosystems and human communities. To explore how changing disturbance regimes might impact future forest health and management it is necessary to understand the historical trends and impacts of disturbance in the region. Although individual types of disturbance have already been analyzed, there is a need for a consolidated overview of the current state of disturbance in northeastern forests. To address this need, the Forest Ecosystem Monitoring Cooperative (FEMC) developed the FEMC: Tracking Shifts in Disturbance Regimes web portal for users to explore changes over time of key disturbance drivers, identify important disturbance responses, and discover where monitoring is happening for both drivers and responses. In collaboration with our advisory committee, we identified key disturbance drivers—flood, high winds, fire, drought, pests—and responses—macroinvertebrates, cold-water fisheries, invasive plants—that are of particular concern in the region. For each of the drivers we identified a suitable regional dataset and analyzed changes over time in frequency, severity, and extent. We also created a structured framework to catalogue programs across the region that are monitoring for these disturbance drivers and responses. Version 1.0 of the FEMC: Tracking Shifts in Disturbance Regimes (https://uvm.edu/femc/disturbance) web portal, first released in October 2021, contains 272 data programs, 11 drivers and three responses. Through the web portal users can browse programs by state, driver type or response type, and explore where monitoring is happening across the region. Driver-specific analyses allow users to quickly see the trends in severity, frequency and extent of selected disturbances and compare the impacts in selected states to regional data. We hope that this collection of programs and the analysis of trends provide researchers and land managers with an easy way to understand the current state of disturbance in northeastern forests that enables them to analyze and plan for future impacts.
APA, Harvard, Vancouver, ISO, and other styles
7

Wolfenson, David, William W. Thatcher, and James E. Kinder. Regulation of LH Secretion in the Periovulatory Period as a Strategy to Enhance Ovarian Function and Fertility in Dairy and Beef Cows. United States Department of Agriculture, December 2003. http://dx.doi.org/10.32747/2003.7586458.bard.

Full text
Abstract:
The general research objective was to increase herd pregnancy rates by enhancing corpus luteum (CL) function and optimizing follicle development, in order to increase conception rate and embryo survival. The specific objectives were: to determine the effect of the duration of the preovulatory LH surge on CL function; to determine the function of LH during the postovulatory period on CL development; to optimize CL differentiation and follicle development by means of a biodegradable GnRH implant; to test whether optimization of CL development and follicle dynamics in timed- insemination protocols would improve fertility in high-yielding dairy cows. Low fertility in cattle results in losses of hundreds of millions of dollars in the USA and Israel. Two major causes of low fertility are formation of a functionally impaired CL, and subsequent enhanced ovarian follicle development. A functionally impaired CL may result from suboptimal LH secretion. The two major causes of low fertility in dairy cattle in US and Israel are negative energy status and summer heat stress; in both situations, low fertility is associated with reductions in LH secretion and impaired development of the ovulatory follicle and of the CL. In Florida, the use of 450-mg deslorelin (GnRH analogue) implants to induce ovulation, under the Ovsynch protocol resulted in a higher pregnancy rates than use of 750-mg implants, and pregnancy losses tended to decrease compared to controls, due probably to decrease in follicular development and estradiol secretion at the time of conceptus signaling to maintain the CL. An alternative strategy to enhance progesterone concentrations involved induction of an accessory CL by injection of hCG on day 5 after the cows were inseminated. Treatment with hCG resulted in 86% of the cows having two CLs, compared with 23% of the control cows. Conception rates were higher among the hCG-treated cows than among the controls. Another approach was to replace the second injection of GnRH analogue, in a timed-insemination protocol, with estradiol cypionate (ECP) injected 24 h after the injection of PGF₂ₐ Pregnancy rates were comparable with those obtained under the regular Ovsynch (timed- AI) program. Use of ECP induced estrus, and cows inseminated at detected estrus are indeed more fertile than those not in estrus at the time of insemination. Collectively, the BARD-supported programs at the University of Florida have improved timed insemination programs. In Ohio, the importance of the frequency of LH episodes during the early stages of the estrous cycle of cattle, when the corpus luteum is developing, was studied in an in vivo experiment in which cows were subjected to various episodic exposures to exogenous bovine LH. Results indicate that the frequent LH episodes immediately following the time of ovulation are important in development of the corpus luteum, from the points of view of both size and functionality. In another study, rates of cell proliferation and numbers of endothelial cells were examined in vitro in CLs collected from cows that received post-ovulation pulsatile LH treatment at various frequencies. The results indicate that the corpora lutea growth that results from luteal cell proliferation is enhanced by the episodes of LH release that occur immediately after the time of ovulation in cattle. The results also show that luteal endothelial cell numbers did not differ among cows treated with different LH doses. In Israel. a longer duration of the preovulatory LH surge stimulated the steroidogenic capacity of granulosa-derived luteal cells, and might, thereby, contribute to a higher progesterone output from the bovine corpus luteum. In an in vivo study, a subgroup of high-yielding dairy cows with extended estrus to ovulation interval was identified. Associated with this extended interval were: low plasma progesterone and estradiol concentrations and a low preovulatory LH surge prior to ovulation, as well as low post- ovulation progesterone concentration. In experiments based on the above results, we found that injection of GnRH at the onset of estrus increased the LHpeak, prevented late ovulation, decreased the variability between cows and elicited high and uniform progesterone levels after ovulation. GnRH at estrus onset increased conception rates, especially in the summer, and among primiparous cows and those with low body condition. Another study compared ovarian functions in multiparous lactating cows with those in nulliparous non-lactating heifers. The results revealed differences in ovarian follicular dynamics, and in plasma concentrations of steroids and gonadotropins that may account for the differences in fertility between heifers and cows.
APA, Harvard, Vancouver, ISO, and other styles
8

Rankin, Nicole, Deborah McGregor, Candice Donnelly, Bethany Van Dort, Richard De Abreu Lourenco, Anne Cust, and Emily Stone. Lung cancer screening using low-dose computed tomography for high risk populations: Investigating effectiveness and screening program implementation considerations: An Evidence Check rapid review brokered by the Sax Institute (www.saxinstitute.org.au) for the Cancer Institute NSW. The Sax Institute, October 2019. http://dx.doi.org/10.57022/clzt5093.

Full text
Abstract:
Background Lung cancer is the number one cause of cancer death worldwide.(1) It is the fifth most commonly diagnosed cancer in Australia (12,741 cases diagnosed in 2018) and the leading cause of cancer death.(2) The number of years of potential life lost to lung cancer in Australia is estimated to be 58,450, similar to that of colorectal and breast cancer combined.(3) While tobacco control strategies are most effective for disease prevention in the general population, early detection via low dose computed tomography (LDCT) screening in high-risk populations is a viable option for detecting asymptomatic disease in current (13%) and former (24%) Australian smokers.(4) The purpose of this Evidence Check review is to identify and analyse existing and emerging evidence for LDCT lung cancer screening in high-risk individuals to guide future program and policy planning. Evidence Check questions This review aimed to address the following questions: 1. What is the evidence for the effectiveness of lung cancer screening for higher-risk individuals? 2. What is the evidence of potential harms from lung cancer screening for higher-risk individuals? 3. What are the main components of recent major lung cancer screening programs or trials? 4. What is the cost-effectiveness of lung cancer screening programs (include studies of cost–utility)? Summary of methods The authors searched the peer-reviewed literature across three databases (MEDLINE, PsycINFO and Embase) for existing systematic reviews and original studies published between 1 January 2009 and 8 August 2019. Fifteen systematic reviews (of which 8 were contemporary) and 64 original publications met the inclusion criteria set across the four questions. Key findings Question 1: What is the evidence for the effectiveness of lung cancer screening for higher-risk individuals? There is sufficient evidence from systematic reviews and meta-analyses of combined (pooled) data from screening trials (of high-risk individuals) to indicate that LDCT examination is clinically effective in reducing lung cancer mortality. In 2011, the landmark National Lung Cancer Screening Trial (NLST, a large-scale randomised controlled trial [RCT] conducted in the US) reported a 20% (95% CI 6.8% – 26.7%; P=0.004) relative reduction in mortality among long-term heavy smokers over three rounds of annual screening. High-risk eligibility criteria was defined as people aged 55–74 years with a smoking history of ≥30 pack-years (years in which a smoker has consumed 20-plus cigarettes each day) and, for former smokers, ≥30 pack-years and have quit within the past 15 years.(5) All-cause mortality was reduced by 6.7% (95% CI, 1.2% – 13.6%; P=0.02). Initial data from the second landmark RCT, the NEderlands-Leuvens Longkanker Screenings ONderzoek (known as the NELSON trial), have found an even greater reduction of 26% (95% CI, 9% – 41%) in lung cancer mortality, with full trial results yet to be published.(6, 7) Pooled analyses, including several smaller-scale European LDCT screening trials insufficiently powered in their own right, collectively demonstrate a statistically significant reduction in lung cancer mortality (RR 0.82, 95% CI 0.73–0.91).(8) Despite the reduction in all-cause mortality found in the NLST, pooled analyses of seven trials found no statistically significant difference in all-cause mortality (RR 0.95, 95% CI 0.90–1.00).(8) However, cancer-specific mortality is currently the most relevant outcome in cancer screening trials. These seven trials demonstrated a significantly greater proportion of early stage cancers in LDCT groups compared with controls (RR 2.08, 95% CI 1.43–3.03). Thus, when considering results across mortality outcomes and early stage cancers diagnosed, LDCT screening is considered to be clinically effective. Question 2: What is the evidence of potential harms from lung cancer screening for higher-risk individuals? The harms of LDCT lung cancer screening include false positive tests and the consequences of unnecessary invasive follow-up procedures for conditions that are eventually diagnosed as benign. While LDCT screening leads to an increased frequency of invasive procedures, it does not result in greater mortality soon after an invasive procedure (in trial settings when compared with the control arm).(8) Overdiagnosis, exposure to radiation, psychological distress and an impact on quality of life are other known harms. Systematic review evidence indicates the benefits of LDCT screening are likely to outweigh the harms. The potential harms are likely to be reduced as refinements are made to LDCT screening protocols through: i) the application of risk predication models (e.g. the PLCOm2012), which enable a more accurate selection of the high-risk population through the use of specific criteria (beyond age and smoking history); ii) the use of nodule management algorithms (e.g. Lung-RADS, PanCan), which assist in the diagnostic evaluation of screen-detected nodules and cancers (e.g. more precise volumetric assessment of nodules); and, iii) more judicious selection of patients for invasive procedures. Recent evidence suggests a positive LDCT result may transiently increase psychological distress but does not have long-term adverse effects on psychological distress or health-related quality of life (HRQoL). With regards to smoking cessation, there is no evidence to suggest screening participation invokes a false sense of assurance in smokers, nor a reduction in motivation to quit. The NELSON and Danish trials found no difference in smoking cessation rates between LDCT screening and control groups. Higher net cessation rates, compared with general population, suggest those who participate in screening trials may already be motivated to quit. Question 3: What are the main components of recent major lung cancer screening programs or trials? There are no systematic reviews that capture the main components of recent major lung cancer screening trials and programs. We extracted evidence from original studies and clinical guidance documents and organised this into key groups to form a concise set of components for potential implementation of a national lung cancer screening program in Australia: 1. Identifying the high-risk population: recruitment, eligibility, selection and referral 2. Educating the public, people at high risk and healthcare providers; this includes creating awareness of lung cancer, the benefits and harms of LDCT screening, and shared decision-making 3. Components necessary for health services to deliver a screening program: a. Planning phase: e.g. human resources to coordinate the program, electronic data systems that integrate medical records information and link to an established national registry b. Implementation phase: e.g. human and technological resources required to conduct LDCT examinations, interpretation of reports and communication of results to participants c. Monitoring and evaluation phase: e.g. monitoring outcomes across patients, radiological reporting, compliance with established standards and a quality assurance program 4. Data reporting and research, e.g. audit and feedback to multidisciplinary teams, reporting outcomes to enhance international research into LDCT screening 5. Incorporation of smoking cessation interventions, e.g. specific programs designed for LDCT screening or referral to existing community or hospital-based services that deliver cessation interventions. Most original studies are single-institution evaluations that contain descriptive data about the processes required to establish and implement a high-risk population-based screening program. Across all studies there is a consistent message as to the challenges and complexities of establishing LDCT screening programs to attract people at high risk who will receive the greatest benefits from participation. With regards to smoking cessation, evidence from one systematic review indicates the optimal strategy for incorporating smoking cessation interventions into a LDCT screening program is unclear. There is widespread agreement that LDCT screening attendance presents a ‘teachable moment’ for cessation advice, especially among those people who receive a positive scan result. Smoking cessation is an area of significant research investment; for instance, eight US-based clinical trials are now underway that aim to address how best to design and deliver cessation programs within large-scale LDCT screening programs.(9) Question 4: What is the cost-effectiveness of lung cancer screening programs (include studies of cost–utility)? Assessing the value or cost-effectiveness of LDCT screening involves a complex interplay of factors including data on effectiveness and costs, and institutional context. A key input is data about the effectiveness of potential and current screening programs with respect to case detection, and the likely outcomes of treating those cases sooner (in the presence of LDCT screening) as opposed to later (in the absence of LDCT screening). Evidence about the cost-effectiveness of LDCT screening programs has been summarised in two systematic reviews. We identified a further 13 studies—five modelling studies, one discrete choice experiment and seven articles—that used a variety of methods to assess cost-effectiveness. Three modelling studies indicated LDCT screening was cost-effective in the settings of the US and Europe. Two studies—one from Australia and one from New Zealand—reported LDCT screening would not be cost-effective using NLST-like protocols. We anticipate that, following the full publication of the NELSON trial, cost-effectiveness studies will likely be updated with new data that reduce uncertainty about factors that influence modelling outcomes, including the findings of indeterminate nodules. Gaps in the evidence There is a large and accessible body of evidence as to the effectiveness (Q1) and harms (Q2) of LDCT screening for lung cancer. Nevertheless, there are significant gaps in the evidence about the program components that are required to implement an effective LDCT screening program (Q3). Questions about LDCT screening acceptability and feasibility were not explicitly included in the scope. However, as the evidence is based primarily on US programs and UK pilot studies, the relevance to the local setting requires careful consideration. The Queensland Lung Cancer Screening Study provides feasibility data about clinical aspects of LDCT screening but little about program design. The International Lung Screening Trial is still in the recruitment phase and findings are not yet available for inclusion in this Evidence Check. The Australian Population Based Screening Framework was developed to “inform decision-makers on the key issues to be considered when assessing potential screening programs in Australia”.(10) As the Framework is specific to population-based, rather than high-risk, screening programs, there is a lack of clarity about transferability of criteria. However, the Framework criteria do stipulate that a screening program must be acceptable to “important subgroups such as target participants who are from culturally and linguistically diverse backgrounds, Aboriginal and Torres Strait Islander people, people from disadvantaged groups and people with a disability”.(10) An extensive search of the literature highlighted that there is very little information about the acceptability of LDCT screening to these population groups in Australia. Yet they are part of the high-risk population.(10) There are also considerable gaps in the evidence about the cost-effectiveness of LDCT screening in different settings, including Australia. The evidence base in this area is rapidly evolving and is likely to include new data from the NELSON trial and incorporate data about the costs of targeted- and immuno-therapies as these treatments become more widely available in Australia.
APA, Harvard, Vancouver, ISO, and other styles
9

Wilson, A. M., and M. C. Kelman. Assessing the relative threats from Canadian volcanoes. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328950.

Full text
Abstract:
This report presents an analysis of the threat posed by active volcanoes in Canada and outlines directives to bring Canadian volcano monitoring and research into alignment with global best practices. We analyse 28 Canadian volcanoes in terms of their relative threat to people, aviation and infrastructure. The methodology we apply to assess volcanic threat was developed by the United States Geological Survey (USGS) as part of the 2005 National Volcano Early Warning System (NVEWS). Each volcano is scored on a number of hazard and exposure factors, producing an overall threat score. The overall threat scores are then assigned to five threat categories ranging from Very Low to Very High. We adjusted the methodology slightly to better suit Canadian volcano conditions by adding an additional knowledge uncertainty score; this does not affect the threat scoring or ranking. Our threat assessment places two volcanoes into the Very High threat category (Mt. Meager and Mt. Garibaldi). Three Canadian volcanoes score in the High threat category (Mt. Cayley, Mt. Price and Mt. Edziza) and two volcanoes score in the Moderate threat category (the Nass River group and Mt. Silverthrone). We compare the ranked Canadian volcanoes to similarly scored volcanoes in the USA and assess the current levels of volcano monitoring against internationally recognised monitoring strategies. We find that even the most thoroughly-studied volcano in Canada (Mt. Meager) falls significantly short of the recommended monitoring level (Mt. Meager is currently monitored at a level commensurate with a Very Low threat edifice, according to NVEWS recommendations). All other Canadian volcanoes are unmonitored (other than falling within a regional seismic network emplaced to monitor tectonic earthquakes). Based on the relative threat and scientific uncertainty surrounding some Canadian volcanoes, we outline five strategies to improve volcano monitoring in Canada and lower the uncertainty about eruption style and frequency: installation of real-time seismic stations at all Very High and High threat volcanoes, comprehensive lithofacies studies at Mt. Garibaldi in order to reduce uncertainty surrounding the frequency and style of volcanism, hazard mapping at Mt. Garibaldi and Mt. Cayley and publication of existing hazard analyses and mapping for Mt. Meager as a comprehensive hazard map, regular satellite-based ground deformation monitoring at all Very High to Moderate threat edifices, and, finally, installation of a landslide detection and alerting system at Mt. Meager.
APA, Harvard, Vancouver, ISO, and other styles
10

Wilson, A. M., and M. C. Kelman. Assessing the relative threats from Canadian volcanoes. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328950.

Full text
Abstract:
This report presents an analysis of the threat posed by active volcanoes in Canada and outlines directives to bring Canadian volcano monitoring and research into alignment with global best practices. We analyse 28 Canadian volcanoes in terms of their relative threat to people, aviation and infrastructure. The methodology we apply to assess volcanic threat was developed by the United States Geological Survey (USGS) as part of the 2005 National Volcano Early Warning System (NVEWS). Each volcano is scored on a number of hazard and exposure factors, producing an overall threat score. The overall threat scores are then assigned to five threat categories ranging from Very Low to Very High. We adjusted the methodology slightly to better suit Canadian volcano conditions by adding an additional knowledge uncertainty score; this does not affect the threat scoring or ranking. Our threat assessment places two volcanoes into the Very High threat category (Mt. Meager and Mt. Garibaldi). Three Canadian volcanoes score in the High threat category (Mt. Cayley, Mt. Price and Mt. Edziza) and two volcanoes score in the Moderate threat category (the Nass River group and Mt. Silverthrone). We compare the ranked Canadian volcanoes to similarly scored volcanoes in the USA and assess the current levels of volcano monitoring against internationally recognised monitoring strategies. We find that even the most thoroughly-studied volcano in Canada (Mt. Meager) falls significantly short of the recommended monitoring level (Mt. Meager is currently monitored at a level commensurate with a Very Low threat edifice, according to NVEWS recommendations). All other Canadian volcanoes are unmonitored (other than falling within a regional seismic network emplaced to monitor tectonic earthquakes). Based on the relative threat and scientific uncertainty surrounding some Canadian volcanoes, we outline five strategies to improve volcano monitoring in Canada and lower the uncertainty about eruption style and frequency: installation of real-time seismic stations at all Very High and High threat volcanoes, comprehensive lithofacies studies at Mt. Garibaldi in order to reduce uncertainty surrounding the frequency and style of volcanism, hazard mapping at Mt. Garibaldi and Mt. Cayley and publication of existing hazard analyses and mapping for Mt. Meager as a comprehensive hazard map, regular satellite-based ground deformation monitoring at all Very High to Moderate threat edifices, and, finally, installation of a landslide detection and alerting system at Mt. Meager.
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'High Frequency Current Injection' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography