Articoli di riviste: "Neutral-Point-Clamped (NPC)"

1

Pakdel, M., e S. Jalilzadeh. "A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters". Engineering, Technology & Applied Science Research 7, n. 2 (24 aprile 2017): 1460–63. http://dx.doi.org/10.48084/etasr.1010.

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This paper presents a novel neutral point clamped full-bridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC) topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM) will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies.

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Shen, Yanxia, Beibei Miao, Dinghui Wu e Kader Ali Ibrahim. "Fault-Tolerant Control Strategy for Neutral-Point-Clamped Three-Level Inverter". Journal of Control Science and Engineering 2018 (1 febbraio 2018): 1–9. http://dx.doi.org/10.1155/2018/5126404.

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A fault-tolerant control technique is discussed for the Neutral-Point-Clamped (NPC) three-level inverter, which ensures that the NPC inverter operates normally even under device failures. A two-level leg is added to the NPC inverter; when the device open circuit fault occurs, the load of this faulty phase is connected to the neutral point of this two-level leg through the bidirectional thyristors. An improved Space Vector Pulse Width Modulation (SVPWM) strategy called “addition and subtraction substitution SVPWM” is proposed to effectively suppress fluctuation in capacitor neutral-point voltages by readjusting the sequence and action time of voltage vectors. The fault-tolerant topology in this paper has the advantages of fewer switching devices and lower circuit costs. Experimental results show that the proposed fault-tolerant system can operate in balance of capacitor neutral-point voltages at full output power and the reliability of the inverter is greatly enhanced.

3

Guo, Yujing, e Junhuai Zhang. "Modulation Technique Design of An Improved Zero Common Mode Voltage (CMV)". Journal of Physics: Conference Series 2563, n. 1 (1 agosto 2023): 012020. http://dx.doi.org/10.1088/1742-6596/2563/1/012020.

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Abstract Voltage imbalance of neutral-point and CMV are hot issues in the research of three-level inverters. This paper first introduces the three-level topology of the neutral-point clamped (NPC) inverter. Aiming to eliminate CMV of three-level NPC and balance the voltage of the neutral point simultaneously, a virtual space vector pulse modulation (VSVPWM) strategy is proposed. Virtual voltage vectors of this strategy are composed of 3 medium vectors. The voltage of the neutral point is balanced since the average current of the neutral point is 0. Therefore, the balance index is introduced to redefine virtual voltage vectors, so the voltage of the neutral point can recover quickly when the capacitors’ voltage of the dc-link is imbalanced.

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Guo, Xiaoqiang, Xuehui Wang, Ran He e Mehdi Narimani. "Modeling and Modulation of NNPC Four-Level Inverter for Solar Photovoltaic Power Plant". International Journal of Photoenergy 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/2383872.

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Photovoltaic (PV) power plant is an attractive way of utilizing the solar energy. For high-power PV power plant, the multilevel inverter is of potential interest. In contrast to the neutral-point clamped (NPC) or flying capacitor (FC) multilevel inverter, the nested neutral point clamped (NNPC) four-level inverter has better features for solar photovoltaic power plant. In practical applications, the common mode voltage reduction of the NNPC four-level is one of the important issues. In order to solve the problem, a new modulation strategy is proposed to minimize the common mode voltage. Compared with the conventional solution, our proposal can reduce the common mode voltage to 1/18 of the DC bus voltage. Moreover, it has the capability to balance the capacitor voltages. Finally, we carried out time-domain simulations to test the performance of the NNPC four-level inverter.

5

Xiaoming Yuan e I. Barbi. "Zero-voltage switching for the neutral-point-clamped (NPC) inverter". IEEE Transactions on Industrial Electronics 49, n. 4 (agosto 2002): 800–808. http://dx.doi.org/10.1109/tie.2002.801064.

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Ek-Iam, Kanyarat, e Yuttana Kumsuwan. "Discontinuous Space Vector Modulation Strategy for Three-Level Neutral Point Clamped Inverter". Applied Mechanics and Materials 781 (agosto 2015): 435–38. http://dx.doi.org/10.4028/www.scientific.net/amm.781.435.

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This paper presents a discontinuous space vector modulation (SVM) strategy for a three-level neutral point clamped (3L-NPC) inverter. The proposed scheme, calculation switching time of the 3L-NPC inverter is fully described. A mathematical analysis of the duty cycle is determined by utilizing the calculated switching time method. The main advantages of the proposed method are minimization of the number of commutations of switches and reduction of the switching losses. Simulated and calculation results are presented to verify the validity and effectiveness of the proposed modulation scheme.

7

Gong, Bo, Shanmei Cheng e Yi Qin. "Simple three-level neutral point voltage balance control strategy based on SVPWM". Archives of Electrical Engineering 62, n. 1 (1 marzo 2013): 15–23. http://dx.doi.org/10.2478/aee-2013-0002.

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Abstract The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC) inverter, the effect of neutral point voltage balancing which is caused by voltage vector is analyzed, and the relationship of the voltage offset and neutral point voltage is studied in this paper. This paper proposes a novel neutral point balance strategy for three-level NPC inverter based on space vector pulse width modulation (SVPWM). A voltage offset is added to the modulation wave, and a closed-loop neutral point voltage balance control system is designed. In the control system, the dwelling time of synthesis voltage vectors for SVPWM is varied to solve the problem of the unbalance of the neutral point voltage, the sequence of the voltage vectors maintains unchanging. Simulation and experimental results show the neutral point voltage balancing control strategy based on SVPWM is effective.

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Reusser, Carlos A., e Hector Young. "Four-Level Quasi-Nested Inverter Topology for Single-Phase Applications". Electronics 10, n. 3 (20 gennaio 2021): 233. http://dx.doi.org/10.3390/electronics10030233.

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In this paper, a novel four-level single-phase multilevel converter is introduced, consisting of six active switches arranged in a quasi-nested configuration. The proposed topology synthesizes its output voltage levels with respect to a floating neutral point, using four cascaded capacitors with identical voltage levels. The proposed converter contains a reduced number of components compared to the neutral point clamped (NPC) or active-NPC topologies (ANPC) for the same number of output voltage levels, since it does not require diode or active switch clamping to a neutral point. Moreover, no floating capacitors with asymmetric voltage levels are employed, thereby simplifying the capacitor voltage balancing. The switching operation principles, modulation technique and control scheme for supplying a single-phase resistive-inductive load are addressed in detail. The proposed four-level inverter allows generating an additional output voltage level with the same semiconductor count as conventional three-level inverters such as NPC and ANPC which allows a superior waveform quality, with a THDv reduction of 32.69% in comparison the clamped inverters. Experimental tests carried out in a laboratory-scale setup verify the feasibility of the proposed topology.

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Puthiyapurayil, Muhammed Ramees Mullali Kunnontakath, Mohamed Nadir Nasirudeen, Yashkumar A. Saywan, Md Waseem Ahmad e Hasmat Malik. "A Review of Open-Circuit Switch Fault Diagnostic Methods for Neutral Point Clamped Inverter". Electronics 11, n. 19 (2 ottobre 2022): 3169. http://dx.doi.org/10.3390/electronics11193169.

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Due to numerous advantages, a neutral point clamped (NPC) inverter is a preferred choice for high-power applications and renewable technology. The reliability of the NPC inverter is a major concerning factor during the assessment of system performance as power semiconductor switches are vulnerable to abnormal conditions. Open-circuit (OC) switch faults are not as dangerous as short circuit (SC) faults but eventually have enough potential to cause cascaded failure to other components in the system and thus need to be supervised carefully. The OC faults result in a distortion of voltage and current signals in the NPC converter. Based on these signals, over the past few years, many efforts have been made to identify and localize the OC switch fault to the switch level in the NPC topology. In this paper, a review of different OC switch fault diagnostic methods is provided. Starting from the NPC inverter operation under healthy and faulty conditions, the various possible and unavailable switching states along with the deviation in pole voltage under different switch fault conditions is discussed. Then, based on the approach used for system-based fault detection, the OC fault detection methods are classified. The various OC methods are further discussed on the basis of signal, i.e., current, voltage or a combination of both signals used as a signature for fault detection. Emphasis is given to the principle involved, diagnostic variables utilized, the implementation approach and the diagnostic time required. Finally, the approaches are tabulated so as to provide a quick reference for NPC fault diagnostics.

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Barros, J. Dionísio, Luis Rocha e J. Fernando Silva. "Backstepping Predictive Control of Hybrid Microgrids Interconnected by Neutral Point Clamped Converters". Electronics 10, n. 10 (19 maggio 2021): 1210. http://dx.doi.org/10.3390/electronics10101210.

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In this work, DC and AC parts of hybrid microgrids are interconnected by a neutral point clamped—NPC converter controlled using a new backstepping predictive (BP) method. The NPC converter is controlled to operate in the DC microgrid voltage control mode or in the AC microgrid power control mode. The novel backstepping predictive controller is designed using the dq state space dynamic model of the NPC converter connected to the hybrid microgrid. The designed BP controller regulates the DC voltage or AC injected power, balances the capacitor voltages, controls the AC currents, and enforces the near unity power factor. Simulation (MATLAB/Simulink) and experimental (laboratory prototype) results show that the converter can regulate the DC voltage in the DC microgrid interconnection point, by adjusting the AC power conversion to compensate variations on the loads or on the distributed renewable energy sources in the DC microgrid. AC currents are sinusoidal with low harmonic distortion. The obtained BP controller is faster at balancing capacitor voltages than PWM (pulse width modulation) control with carrier offset. The fast AC power response allows the converter to be used as a primary frequency regulator of the AC microgrid. This research is appropriate for power and voltage control in hybrid microgrids with renewable energy.

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Ye, Zongbin, Yiming Xu, Fei Li, Xianming Deng e Yuanzheng Zhang. "Simplified PWM Strategy for Neutral-Point-Clamped (NPC) Three-Level Converter". Journal of Power Electronics 14, n. 3 (20 maggio 2014): 519–30. http://dx.doi.org/10.6113/jpe.2014.14.3.519.

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Enjeti, P. N., e R. Jakkli. "Optimal power control strategies for neutral point clamped (NPC) inverter topology". IEEE Transactions on Industry Applications 28, n. 3 (1992): 558–66. http://dx.doi.org/10.1109/28.137436.

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Chen, Guo, Chunyang Gong, Jun Bao, Lihua Zhu e Zhixin Wang. "Compensation-Voltage-Injection-Based Neutral-Point Voltage Fluctuation Suppression Method for NPC Converters". Energies 16, n. 11 (30 maggio 2023): 4409. http://dx.doi.org/10.3390/en16114409.

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Three-level neutral-point clamped (NPC) inverters are widely used in the new energy power generation, motor drive, and many other occasions. However, the neutral-point voltage imbalance of an NPC inverter will affect the output of the inverter system, and the control of the neutral point voltage has become a popular research topic. In this paper, a compensation-voltage-injection-based neutral-point voltage balancing method is proposed. During the switching cycle, the average value model of the neutral-point current under different voltage vectors is applied to calculate the value of the compensation voltage that needs to be injected. The self-balance of the neutral-point voltage based on a switching cycle is realized, and the influence of modulation ratio and power factor on equalization ability is discussed. A MATLAB/Simulink simulation model and a small power prototype are established to verify the effectiveness of the method, and the simulation and experimental results show that the proposed method can effectively suppress the neutral-point voltage fluctuation in a wide range of modulation ratios and power factors.

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Kim, Ju-Yong, Ho-Sung Kim, Ju-Won Baek e Dong-Keun Jeong. "Analysis of Effective Three-Level Neutral Point Clamped Converter System for the Bipolar LVDC Distribution". Electronics 8, n. 6 (19 giugno 2019): 691. http://dx.doi.org/10.3390/electronics8060691.

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Low-voltage direct current (LVDC) distribution has attracted attention due to increased DC loads, the popularization of electric vehicles, energy storage systems (ESS), and renewable energy sources such as photovoltaic (PV). This paper studies a ±750 V bipolar DC distribution system and applies a 3-level neutral-point clamped (NPC) AC/DC converter for LVDC distribution. However, the 3-level NPC converter is fundamental in the neutral-point (NP) imbalance problem. This paper discusses the NP balance control method using zero-sequence voltage among various solutions to solve NP imbalance. However, since the zero-sequence voltage for NP balance control is limited, the NP voltage cannot be controlled to be balanced when extreme load differences occur. To maintain microgrid stability with bipolar LVDC distribution, it is necessary to control the NP voltage balance, even in an imbalance of extreme load. In addition, due to the bipolar LVDC distribution, the pole where a short-circuit condition occurs limits the short current until the circuit breaker operates, and a pole without a short-circuit condition must supply a stable voltage. Since the conventional 3-level NPC AC/DC converter alone cannot satisfy both functions, an additional DC/DC converter is proposed, analyzed, and verified. This paper is about a 3-level NPC AC/DC converter system for LVDC distribution. It can be used for the imbalance and short-circuit condition in bipolar LVDC distribution through the prototype of the 300 kW 3-level NPC AC/DC converter system and experimented and verified in various conditions.

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Dong, Ting Ting, Jiu He Wang e Xian Qin Ma. "Passivity Based Hybrid Controller of Dual Euler Lagrange Model of Three-Level Three-Phase Neutral Point Clamped Voltage Source Rectifier". Advanced Materials Research 860-863 (dicembre 2013): 2378–81. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.2378.

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The PBHC (Passivity Based Hybrid Controller, PBHC) with damping injection and neutral point potential balance was based on a dual-EL (Euler Lagrange, EL) model of three-level three-phase dual load NPC (Neutral Point Clamped, NPC) VSR (Voltage Source Rectifier, VSR) in dq reference frame. The simulation results from Matlab/Simulink show that the proposed control strategy has excellent performances: at the AC side, the THD (Total Harmonious Distortion, THD) is less than 5%, the PF (Power Factor, PF) is higher than 98%; at the DC side, the output voltage is able to track the desired voltage quickly, the capacitors votages are equal.

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Madasamy, P., Rajesh Verma, A. Rameshbabu, A. Murugesan, R. Umamageswari, Josiah Lange Munda, C. Bharatiraja e Lucian Mihet-Popa. "Neutral Point Clamped Transformer-Less Multilevel Converter for Grid-Connected Photovoltaic System". Electronics 10, n. 8 (19 aprile 2021): 977. http://dx.doi.org/10.3390/electronics10080977.

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Transformer-less (TL) inverter topologies have elicited further special treatment in photo-voltaic (PV) power system as they provide high efficiency and low cost. Neutral point clamped (NPC) multilevel-inverter (MLI) topologies-based transformer-less are being immensely used in grid-connected medium-voltage high-power claims. Unfortunately, these topologies such as NPC-MLI, full-bridge inverter with DC bypass (FB-DCBP) suffer from the shoot-through problem on the bridge legs, which affect the reliability of the implementation. Based on the previous above credits, a T type neutral point clamped (TNP)—MLI (TNP-MLI) with transformer-less topology called TL-TNP-MLI is presented to be an alternate which can be suitable in the grid-connected PV power generation systems. The suggested TL-TNP-MLI topologies free from inverter bridge legs shoot-through burden, switching frequency common-mode current (CMC), and leakage current. The control system of the grid interface with hysteresis current control (HCC) strategy is proposed. The effectiveness of the proposed PV connected transformer-less TNP-MLI topology with different grid and PV scenario has been verified through the MATLAB/Simulink simulation model and field-programmable gate area (FPGA)-based experimental results for a 1.5 kW system.

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Wang, Lu Jun, Tao Gong e Jun Zhu. "Robust Predictive Control for NPC Grid-Connected Inverters". Applied Mechanics and Materials 668-669 (ottobre 2014): 522–25. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.522.

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In this paper, the state space model of neutral point clamped three-level grid-connected inverter is detailed derived and an Robust Predictive Control (RPC) method is proposed. In the proposed method, the total 27 switching vectors composed of a finite set from which the optimal switching vector is selected according to a cost function. The robust performance is improved just by increasing switching frequency. Experimental results show that the proposed method has a flexible control purposes and we can optimize the synthesize performance just by adjusting weighting coefficients of cost function. In addition, RPC controller has a robust performance in tracking output reference current and balancing neutral point voltage.

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R, Palanisamy, e K. Vijayakumar. "SVPWM for 3-phase 3-level Neutral Point Clamped Inverter Fed Induction Motor Control". Indonesian Journal of Electrical Engineering and Computer Science 9, n. 3 (1 marzo 2018): 703. http://dx.doi.org/10.11591/ijeecs.v9.i3.pp703-710.

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This paper gives Space Vector Pulse Width Modulation (SVPWM) for 3-phase 3-level Neutral Point Clamped (NPC) inverter fed induction motor control. A conventional two level inverter with 3-phase system has been developed for induction motor control. When it is applied for high voltage and power applications, which increases the voltage stress across the switch and harmonic content in the output. So multilevel inverter is much suitable for induction motor control, which provides nearly sinusoidal output voltage and diminished harmonic content in the output. Also the stator current of induction motor is minimsed, speed and torque of induction motor controlled with appropriate switching NPC inverter using SVPWM method. The proposed system simulation are verified using matlab simulink.

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Mlodzikowski, Pawel, Adam Milczarek e Mariusz Malinowski. "Application of Simplified Neutral Point Clamped Multilevel Converter in a Small Wind Turbine". Electrical, Control and Communication Engineering 5, n. 1 (1 maggio 2014): 5–10. http://dx.doi.org/10.2478/ecce-2014-0001.

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Abstract In low power distributed generation systems low cost together with the energy quality requirements are a key element. It is known that quality of voltage waveforms generated from multilevel converters is better in comparison with those from two-level. Due to advancements in power electronics and microcontrollers, multilevel converters are being built with the use of integrated power modules thus this type of converters are getting more compact in size. This paper investigates performance of a derivation from the most popular multilevel topology - a neutral point clamped converter (NPC). Applying the idea for simplifying the topology by reducing the number of switches (what came from drives) this NPC converter is capable of bidirectional AC/DC/AC operation. For the AC/DC part two schemes are tested: Direct Torque Control Space Vector Modulated and Field Oriented Control but for the DC/AC part a control scheme utilizing the proportional-resonant controller was chosen. Laboratory setup was based on a permanent magnet synchronous generator with control and acquisition completed with the help of dSpace 1005 control box. Experimental verification shows that system operates properly.

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Benioub, Rabie, Laid Kadri, Mohamed Adnane e Kenji Itaka. "Modulation Index Variation Effect on Harmonic Behavior of Fifteen Multilevel Inverter Neutral-Point-Clamped Topology". International Journal of Electrical and Computer Engineering (IJECE) 7, n. 4 (1 agosto 2017): 1892. http://dx.doi.org/10.11591/ijece.v7i4.pp1892-1898.

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The Market for photovoltaic cells (PV) has grown fast due to a higher demand on PV applications. However, there are still the transport and connection problems of the PV systems to the grid because of the difference in the current form. To assure the adequate connection between the PV sources and the network, the conversion of direct current (DC) to an alternative current (AC) is required and provided by an electronic device known as the inverter. In this last years, the conventional inverter structure reached its limits in power level and conversion performance. The multilevel inverter (MLI) structure was introduced and widely used in high power and high voltage applications to solve the conventional inverter limitation problem. In this paper, the Neutral-Point-Clamped (NPC) topology of the MLI was simulated to evaluate the effect of modulation index variation of the control technique on the harmonic behavior of the fifteen-level NPC. The simulation results were useful for the optimization of the MLI control technique toward the decrease of the harmonic (THD) effect on the NPC MLI.

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Peng, Xi, Sheng Yin e Yingqin Zou. "Research on dynamic current sharing method of parallel connected IGBT modules for NPC three level converters". Journal of Physics: Conference Series 2113, n. 1 (1 novembre 2021): 012055. http://dx.doi.org/10.1088/1742-6596/2113/1/012055.

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Abstract The parallel connection of IGBTs has been being applied in high power neutral point clamped (NPC) three level converters. This paper investigates the impact of gate parameters (gate resistor and capacitance) on dynamic current imbalance of parallel connected IGBT for NPC three level converter. A gate parameters calculation method is proposed in the paper, and the delay time and collector current difference can be analysed quantitatively. Experimental results have shown the effectiveness of the method.

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Omri, B., L. Fakhfakh, K. Ammous e A. Ammous. "Validation of a Nonlinear Average Model of NPC Inverters Based on Experimental Investigations". International Journal of Emerging Electric Power Systems 17, n. 6 (1 dicembre 2016): 717–29. http://dx.doi.org/10.1515/ijeeps-2016-0090.

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Abstract This paper proposes a nonlinear average model of three levels NPC inverter. This model takes into account the semiconductor non-linearity and static characteristics of these devices. The proposed technique uses experimental results to evaluate the different devices parameters. The developed nonlinear average model allows dissipated power and junction temperature evaluation. Unlike the circuit model (fine model), the proposed method has less computational burden. It can be applied to three levels Neutral-Point-Clamped inverter (NPC).

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Jing, Wei, e Ran Ding. "Loss Analysis of Three-Level Active Neutral Point Clamped Converter under Fault Tolerance Operation". Advanced Materials Research 588-589 (novembre 2012): 847–50. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.847.

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Compared with traditional three-level neutral-point-clamped (NPC) converter, the recently proposed three-level active NPC (ANPC) converter has the ability to overcome the unbalanced loss distribution, and therefore result in increased output power or switching frequency. In industrial applications, fault tolerance ability of power converters is very important considering system availability, safety and reliability. This paper introduced the control schemes to get stable and continuous output under single device fault for both open-circuit and short-circuit fault cases. By analyzing the phase relationship of reference voltage and load current, the loss calculation method under fault tolerant operation was proposed. Calculation results show that the devices junction temperatures under fault tolerant operation are within the safe operation area (SOA) even they are a little bit higher compared to normal operation, which also confirm the effectiveness of the fault tolerant control schemes.

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Scholtz, Pieter Antonie, e Michael Njoroge Gitau. "Asymmetric Neutral Point Diode Clamped Topology with Reduced Component Count for Switched Reluctance Machine Drive". Energies 15, n. 7 (27 marzo 2022): 2468. http://dx.doi.org/10.3390/en15072468.

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The Reduced Asymmetric Neutral Point Clamped converter topology for unipolar driven, multiphase switched reluctance machines is proposed in this paper. This topology shares similarities with the conventional NPC and Asymmetric-NPC topologies, however it is unique in that the components for the capacitor string and outer semiconductor switches are shared among all the phases for a reduced component count. Some switching state combinations are not possible during commutation overlap between motor phases, resulting in minor torque transients during regenerative braking. A custom modulation scheme is implemented with fixed frequency, phase-shifted carrier waveforms that allow for automatic balancing of the neutral point voltage and interleaved switching of the semiconductor switches. A simple torque observer control architecture is used with minor adjustments for arbitrating torque contribution priorities between phases during handover.

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Edwin Deepak, F. X., e V. Rajasekaran. "Three phase z-source neutral point clamped inverter with multicarrier PWM technique". COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 35, n. 5 (5 settembre 2016): 1575–91. http://dx.doi.org/10.1108/compel-04-2016-0131.

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Purpose The purpose of this paper is to present the three phase seven-level Z-source neutral point clamped (NPC) inverter with multicarrier pulse-width modulation (PWM) technique. Despite numerous topologies and modulation methods, there is a dire need of developing PWM techniques that can be deployed in multilevel inverters. These inverters decrease the total harmonic distortion and it has a good performance for various electrical power system applications. The proposed inverter is investigated for its performance by executing it in shoot through and non-shoot through modes. Design/methodology/approach The purpose is validated through MATLAB/Simulink software platform for implementing the proposed seven-level Z-source NPC inverter outlined with multicarrier based phase disposition technique. The experimental results are verified using SPARTAN 3E FPGA controller with the same control strategy. Findings The efficiency of the proposed inverter is confirmed in terms of increased and faster conversion in the shoot-through mode. By using PDPWM technique the maximum boost gain is achieved with lower modulation index. High control of DC voltage is obtained with only one DC voltage source and one Z network. Originality/value Three phase multilevel inverters are widely used in improving the output voltage quality and reducing the encountered electromagnetic interference in electronic device or circuitry. They are employed in medium and high –power applications to attain increased power ratings while decreasing the switching losses. The performance results shown in this paper will satisfy the above needs of usage in certain applications and less switching losses.

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Rajasekaran, P., e V. Jawahar Senthilkumar. "An Improved DTFC based Five Levels - NPC Inverter Fed Induction Motor for Torque Ripple Minimization". International Journal of Power Electronics and Drive Systems (IJPEDS) 7, n. 2 (1 giugno 2016): 531. http://dx.doi.org/10.11591/ijpeds.v7.i2.pp531-542.

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This paper presents a five level Neutral Point Clamped (NPC) inverter fed IM (Induction Motor) drive for variable speed application. In general the stator current is very highly affected by the harmonic components. It can be affecting the torque to produce high torque ripple in IM at maximum to low speed region. Since the drive performances are depends on mathematical model contains the parameters variations, noise, common mode voltage, flux variation and harmonic levels of the machine. Torque ripples and voltage saturations are the most significant problems in drive application. To overcome this problem the DTFC (direct torque and flux control) technique based ﬁve-level neutral-point-clamped (NPC-5L) approach is used. The proposed control scheme uses to stator current error as variable. Through the resistance estimated PI controller rules based the selection of voltage space vector modulation technique is optimized and motor performance level has been improved. The torque & speed are successfully controlled with less torque response. The results are compared and verified with conventional three phases VSI under different control technique by Matlab/Simulink.

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Ge, Xuefeng, Mengxing Chen, Mingming Shi, Qi Zhou, Juan Li, Di Huang, Xiaodong Yuan e Yubo Yuan. "A Single-Stage Buck-Boost Three-Level Neutral-Point-Clamped Inverter with Two Input Sources for the Grid-Tied Photovoltaic Power Generation". Mathematical Problems in Engineering 2019 (2 aprile 2019): 1–15. http://dx.doi.org/10.1155/2019/3238159.

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Abstract (sommario):

This paper proposes a novel single-stage buck-boost three-Level neutral-point-clamped (NPC) inverter with two independent dc sources coupled for the grid-tied photovoltaic (PV) application, which can effectively solve the unbalanced operational conditions generally appearing between two independent PV sources. The proposed control scheme can simultaneously guarantee the maximum power point (MPP) operation of both PV sources and maintain the output waveform quality. Compared to the traditional two-stage PV inverter, the proposed NPC inverter could reduce the PV array voltage requirement and the voltage rating of dc-link capacitors; also it shows advantages in operational efficiency. MATLAB simulations and experimental results are presented to examine the performance of the proposed three-level NPC inverter.

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N. Uday Kumar, Et al. "Implementation of Passivity-based Control of Four-Leg Inverter for Transformerless Three-Phase Solar Photovoltaic Systems". International Journal on Recent and Innovation Trends in Computing and Communication 11, n. 9 (30 novembre 2023): 3890–900. http://dx.doi.org/10.17762/ijritcc.v11i9.9669.

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This study explores the application of a passivity-based control technique (PBC) with an artificial neuro-fuzzy inference system (ANFIS) in a grid-connected Solar Photovoltaic (SPV) generating system for estimating reference grid currents. To optimise the tracking of the maximum power point (MPPT) between the solar photovoltaic (SPV) system and the DC bus, a DC – DC boost converter (BC) is utilised. This converter is connected to a four-leg, three-level neutral-point-clamped converter (4-leg 3L-NPC), interfaced with a three-phase, four-wire distribution system. The four-leg 4-leg 3L-NPC of the SPV generating system with Space vector pulse width modulation technique (SVPWM) is utilised for reducing common-mode voltage (CMV), leakage current (LC), reactive power for zero voltage regulation, power factor correction, load balancing, and the elimination of load harmonic currents in the proposed distribution system.The performance analysis of the proposed system is conducted on the Matlab/Simulink platform. Additionally, a comparative analysis is presented, contrasting the proposed system with a 3-phase 4-leg T-type neutral-point-clamped converter (TNPC) employing the PBC technique followed by ANFIS.

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R, Palanisamy. "Hysteresis Control 3-Level SI-NPC Inverter with Wind Energy System". International Journal of Power Electronics and Drive Systems (IJPEDS) 8, n. 4 (1 dicembre 2017): 1764. http://dx.doi.org/10.11591/ijpeds.v8.i4.pp1764-1770.

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Abstract (sommario):

The system is a 3-level Neutral point clamped hysteresis current controlled Inverter with Wind energy as power source. The input DC Power for the multi-level inverter is drawn from wind turbine generator connected through a rectifier circuit. An inductor has been introduced for smoothening the DC output from the rectifier. The inverter uses Neutral Point Clamped topology. The switching pulses for the inverter are achieved by hysteresis current control technique. This system is advantageous over the conventional SPWM based system as the hysteresis current control allows to reduce the low frequency harmonics while also allowing to control the fundamental amplitude depending on frequency. The outputs for the system are verified using MATLAB simulations. The hardware for Hysteresis current control for the inverter is implemented by using a dSPIC microcontroller. The proposed system can be implemented in households for supplying backup power in case of power shortage and can also be used as a primary power source if wind flow is abundant. It is easy to implement, economical and provides clean energy

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Chen, Cui, e Yin Zhong Ye. "Research on Vector Control of PMSM Based on Three-Level NPC Inverter-Fed". Advanced Materials Research 542-543 (giugno 2012): 854–58. http://dx.doi.org/10.4028/www.scientific.net/amr.542-543.854.

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Abstract (sommario):

The neutral point clamped (NPC) pulse width modulation (PWM) inverter has been put into practical use for large capacity AC motor drives because of its less distorted output, lower costs and better control performance. This paper suggests a way to improve the performance of permanent magnet synchronous motor (PMSM) by using the three-level NPC inverter. Firstly, the three-level NPC inverter space voltage vector pulse width modulation (SVPWM) technique is analyzed in detail. Then, the NPC inverter is applied in PMSM vector control. Finally, a simulation experiment of the proposed control algorithm is carried out. The simulation results show that the proposed method can effectively suppress the torque ripple and improve driving performance for the PMSM drive.

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Suresh Kumar Annam e N. Yadaiah. "A hysteresis current control PWM for PV tied Z-source NPC-MLI fed induction motor with neutral point balancing". International Journal of Science and Research Archive 7, n. 2 (30 dicembre 2022): 542–54. http://dx.doi.org/10.30574/ijsra.2022.7.2.0339.

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Photo-voltaic (PV) tied Z-source Neutral-point clamped NPC-MLI (Z-NPC-MLI) is used in solar grid connected applications due to its improved performance related to conservative inverters due to its single stage power conversion. Though the Z source inverters adaptation is accepted in grid connected technology, the need for appropriate controller to meet out the grid/standalone requirements is becoming necessary. The space vector pulse width modulation (SVPWM) strategy is a prominent modulation technique for Z-source NPC-MLIs due to their appropriate voltage vector selection opportunity. The current controller (CC) based SVPWM is not attempted, which is the most essential consideration for the grid connected inverter to provide a low harmonic distortion, high quality current. With all this aim, the paper presents a PV tied Z-NPC-MLI grid connected system with a unique hysteresis current control SVPWM (HSVM) strategy with neutral point (NP) balancing control. The simulation results are confirmed the feasibility and reliability of the proposed CC for the PV tie grid connected Z- Source MLI.

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Kishore, D. Ravi, T. Vijay Muni, B. Srinivas Raja, Mukesh Pushkarna, B. Srikanth Goud, Kareem M. AboRas e Sadam Alphonse. "Grid-Connected Solar PV System with Maximum Power Point Tracking and Battery Energy Storage Integrated with Sophisticated Three-Level NPC Inverter". International Transactions on Electrical Energy Systems 2023 (25 luglio 2023): 1–20. http://dx.doi.org/10.1155/2023/3209485.

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In this research, a solar photovoltaic system with maximum power point tracking (MPPT) and battery storage is integrated into a grid-connected system using an improved three-level neutral-point-clamped (NPC) inverter. An NPC inverter with adjustable neutral-point clamping may achieve this result. To achieve this result, a modernized NPC inverter is used. Using the three-level vector modulation approach, the correct AC voltage may be generated when DC voltage conditions are present in an unbalanced situation involving an NPC inverter. A higher degree of precision is made possible by this. In-depth information on the many possible NPC inverter designs and modulation strategies was provided. By incorporating the necessary sophisticated algorithms into the NPC inverter, the necessary solar PV-MPPT functionality is made available, allowing for the regulation of power transfer among the solar PV system, the battery, and the grid. Modified INC method is proposed which has a tracking efficiency of 99.5% for varying irradiance. The use of sufficiently sophisticated algorithms makes this a reality. Using simulation with MATLAB/Simulink, we were able to examine an NPC inverter’s performance in several setups. Several amounts of solar irradiation were used to test the battery’s charging and discharging capabilities. The probe turned out to be fruitful. Laboratory testing ensures that the proposed method works by simulating real-world conditions.

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Quy, Do Ngoc, Do Ba Phu e Nguyen Kien Trung. "The new approach minimizes harmonics in a single-phase three-level NPC 400 Hz converter for airplanes". International Journal of Power Electronics and Drive Systems (IJPEDS) 12, n. 3 (1 settembre 2021): 1738. http://dx.doi.org/10.11591/ijpeds.v12.i3.pp1738-1750.

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Abstract (sommario):

This paper provides a new approach to reducing high-order harmonics in 400 Hz inverter using a three-level neutral-point clamped (NPC) converter. A voltage control loop using the harmonic compensation combined with NPC clamping diode control technology. The capacitor voltage imbalance also causes harmonics in the output voltage. For 400 Hz inverter, maintain a balanced voltage between the two input (direct current) (DC) capacitors is difficult because the pulse width modulation (PWM) modulation frequency ratio is low compared to the frequency of the output voltage. A method of determining the current flowing into the capacitor to control the voltage on the two balanced capacitors to ensure fast response reversal is also given in this paper. The combination of a high-harmonic resonator controller and a neutral-point voltage controller working together on the 400 Hz NPC inverter structure is given in this paper.

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Zhang, Guozheng, Yingjie Su, Zhanqing Zhou e Qiang Geng. "A Carrier-Based Discontinuous PWM Strategy of NPC Three-Level Inverter for Common-Mode Voltage and Switching Loss Reduction". Electronics 10, n. 23 (5 dicembre 2021): 3041. http://dx.doi.org/10.3390/electronics10233041.

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Abstract (sommario):

For the conventional carrier-based pulse width modulation (CBPWM) strategies of neutral point clamped (NPC) three-level inverters, the higher common-mode voltage (CMV) is a major drawback. However, with CMV suppression strategies, the switching loss is relatively high. In order to solve the above issue, a carrier-based discontinuous PWM (DPWM) strategy for NPC three-level inverter is proposed in this paper. Firstly, the reference voltage is modified by the twice injection of zero-sequence voltage. Switching states of the three-phase are clamped alternatively to reduce both the CMV and the switching loss. Secondly, the carriers are also modified by the phase opposite disposition of the upper and lower carriers. The extra switching at the border of two adjacent regions in the space vector diagram is reduced. Meanwhile, a neutral-point voltage (NPV) control method is also presented. The duty cycle of the switching state that affects the NPV is adjusted to obtain the balance control of the NPV. Still, the switching sequence in each carrier period remains the same. Finally, the feasibility and effectiveness of the proposed DPWM strategy are tested on a rapid control prototype platform based on RT-Lab.

35

Wang, Yingjie, Haiyuan Liu, Wenchao Wang e Kangan Wang. "A Novel Neutral-Point Potential Balance Strategy for Three-Level NPC Back-to-Back Converter Based on the Neutral-Point Current Injection Model". Mathematical Problems in Engineering 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/736828.

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Abstract (sommario):

The neutral-point (NP) potential balance control in three-level neutral-point-clamped (NPC) back-to-back converter is a research nodus. Its current strategies are the same as the strategies of a single three-level NPC converter. But the strategies do not give full play to its advantages that the neutral-point current can only flow through the connected midlines in both sides of the converter but does not flow through the DC-bus capacitors. In this paper, firstly the NP potential model based on the NP current injected is proposed. It overcomes numerous variable constraints and mutual coupling in the conventional model based on the zero-sequence voltage injected. And then on this basis, three NP-potential balance control algorithms, unilateral control, bilateral independent control, and bilateral coordinated control, are proposed according to difference requirements. All of these algorithms use the midlines rather than the DC-bus capacitors to flow the NP current as much as possible. Their control abilities are further quantitatively analyzed and compared. Finally, simulation results verify the validity and effectiveness of these algorithms.

36

Yue, Xiumei, Hongliang Wang, Xiaonan Zhu, Xinwei Wei e Yan-Fei Liu. "A Topology Synthetization Method for Single-Phase, Full-Bridge, Transformerless Inverter with Leakage Current Suppression—Part II". Energies 13, n. 2 (16 gennaio 2020): 446. http://dx.doi.org/10.3390/en13020446.

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This paper proposes a topology derivation methodology to achieve small leakage current or zero leakage current for photovoltaic application. The core of the proposed method is a unified topology model and MN principle to show how to derive all possible topologies based on unipolar sinusoidal pulse width modulation (USPWM) and double-frequency USPWM (DFUSPWM). Part II of this paper discusses the topology synthetization method to achieve zero leakage current. Two types of neutral point clamped (NPC) topologies based on USPWM and DFUSPWM are elaborated. Two possible connections for the NPC cell are introduced, and detailed NPC topology derivation procedures are also provided. All existing NPC topologies are derived, and twenty-two new NPC topologies are found based on the new topology derivation methodology for a single-phase, full-bridge, transformerless inverter.

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Zhang, Maosong, Ying Cui, Qunjing Wang, Jun Tao, Xiuqin Wang, Hongsheng Zhao e Guoli Li. "A Study on Neutral-Point Potential in Three-Level NPC Converters". Energies 12, n. 17 (1 settembre 2019): 3367. http://dx.doi.org/10.3390/en12173367.

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Abstract (sommario):

This paper proposes an accurate mathematical model of three-level neutral-point-clamped (NPC) converters that can accurately represent the midpoint potential drift of the DC link with parameter perturbation. The mathematical relationships between the fluctuation in neutral-point voltage, the parametric perturbation, and the capacitance error are obtained as mathematical expressions in this model. The expressions can be used to quantitatively analyze the reason for the neutral-point voltage imbalance and balancing effect based on a zero-sequence voltage injection. The injected zero-sequence voltage, which can be used to balance the DC-side voltages with the combined action of active current, can be easily obtained from the proposed model. A balancing control under four-quadrant operation modes is proposed by considering the active current to verify the effectiveness of this model. Both the simulation and experiment results validate the excellent performance of the proposed model compared to the conventional model.

38

Laoufi, Chaymae, Zouhair Sadoune, Ahmed Abbou e Mohammed Akherraz. "New model of electric traction drive based sliding mode controller in field-oriented control of induction motor fed by multilevel inverter". International Journal of Power Electronics and Drive Systems (IJPEDS) 11, n. 1 (1 marzo 2020): 242. http://dx.doi.org/10.11591/ijpeds.v11.i1.pp242-250.

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This paper presents a new model of electric traction drive for electric vehicle. The sliding mode speed controller applied in the Indirect Rotor Field Oriented Control is used to control the induction motor fed by the five levels Neutral Point Clamped inverter (NPC). The simulation results showed the high performances dynamics and high robustness of the proposed model, that are reflected by faster startup and good speed tracking performances in terms of response time, oscillations and disturbance rejection. Also, a comparative study between different inverter topologies: two levels inverter, three levels NPC inverter and five levels NPC inverter has been carried out. From the spectral analysis, the five-levels NPC inverter fed drive provides better dynamics of voltage and current with reduced total harmonic distortion (THD).

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Wang, Ziying, Ning Jiao, Shunliang Wang, Junpeng Ma, Rui Zhang e Tianqi Liu. "Quantitative Analysis of Balancing Range for Single-Phase 3L-NPC Converters". Energies 17, n. 6 (19 marzo 2024): 1464. http://dx.doi.org/10.3390/en17061464.

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Abstract (sommario):

Multiple techniques have been suggested to achieve control balance in single-phase three-level neutral-point clamped (3L-NPC) converters. Nevertheless, there is a deficiency of quantitative calculations related to the extent of balancing. Operating beyond the balancing range may result in a sequence of safety incidents. This paper presents a conceptualization of the 3L-NPC converter as two cascaded H-bridges. By employing power conservation principles, the balancing range for the NPC converter is derived, and two novel methods are investigated to broaden the balance range in accordance with the calculated balance range. A comparison is made among the balancing ranges under different balancing control methods. This study establishes a theoretical foundation to ensure the secure and stable operation of the NPC converter.

40

Sun, Yu Xin, Chang Sheng Xu e Huang Qiu Zhu. "A Three-Level DTC System Based on Virtual Space Vector Modulation for Bearingless Permanent Magnet Synchronous Motor". Applied Mechanics and Materials 703 (dicembre 2014): 356–59. http://dx.doi.org/10.4028/www.scientific.net/amm.703.356.

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In This paper, a direct torque control (DTC) method for bearingless permanent magnet synchronous motor (BPMSM) based on three-level neutral-point clamped (NPC) inverter is described. Through the analysis of virtual space vector modulation, an independent control strategy is adopted into the suspension winding control and a flux linkage error vector SVM-DTC method supplied by three-level NPC inverter is introduced into the torque windings control. By using the proposed control strategy, the neutral-point voltage variation can be greatly limited and the voltage shifting can be eliminated. The results of simulation verify the feasibility of the control algorithm, the dv/dt of output voltage and the torque ripple are restrained effectively, satisfactory robustness and the good performance of the radial levitation can be achieved in a wide speed range by using the proposed method.

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Akbari, Ehsan, e Farhad Zishan. "Modified Topology and Modulation Technique for Z-Source Neutral-Point Clamped Inverter". Power Electronics and Drives 7, n. 1 (1 gennaio 2022): 210–26. http://dx.doi.org/10.2478/pead-2022-0016.

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Abstract The impedance network makes it possible to increase and decrease the voltage, which is not available in normal inverters (voltage and current sources).This paper presents a modified topology and modulation technique for a three-phase Modified Z-Source Neutral-Point Clamped (MZS-NPC) inverter. A modulation scheme for the proposed topology is designed based on maximum gain control method to achieve the maximum voltage gain by simple implementation and balancing the neutral point voltage of the dc link. In order to supply the desired voltage to the critical load in an islanded micro-grid, a closed-loop ac voltage controller is realized in fuel cell or photovoltaic applications based on the proposed inverter. The ability to reinforce and validity of topology operations and modulation techniques has been demonstrated by simulation. It should be noted that the simulations are implemented in MATLAB / Simulink software.

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Izzaqi, Fahmi Ahyar, Novie Ayub Windarko e Ony Asrarul Qudsi. "Minimization of total harmonic distortion in neutral point clamped multilevel inverter using grey wolf optimizer". International Journal of Power Electronics and Drive Systems (IJPEDS) 13, n. 3 (1 settembre 2022): 1486. http://dx.doi.org/10.11591/ijpeds.v13.i3.pp1486-1497.

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The inverter has been attracting researchers for their application in renewable energy. So far, multilevel inverter is considered as low distortion class, which produces multilevel output voltage imitating a pure sine waveform. However, the needs for free distortion of output voltage have been motivating to improve multilevel pulse width modulation PWM generation method. In this paper, the modified PWM technique is proposed to reduce the voltage total harmonics distortion (THD) of multilevel inverter. This modulation technique is then applied to control a single-phase threelevel neutral point clamped multilevel inverter (NPC-MLI). Grey wolf optimizer (GWO) algorithm is utilized to generate optimal amplitude and phase shift of modified reference signal. The GWO algorithm is then compared with other optimization algorithms such as differential evolution (DE), human psychology optimization (HPO), and particle swarm optimization (PSO) to evaluate their performance in harmonic minimization. The performance of the proposed work is validated through simulation and experimentation on a prototype. The results show that the modified PWM technique optimized with GWO can reduce THD on NPC-MLI output voltage.

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Wan, Shaoqi, Bo Wang, Jingbo Chen, Haiying Dong e Congxin Lv. "Model Predictive Control Strategy Based on Loss Equalization for Three-Level ANPC Inverters". Actuators 13, n. 3 (12 marzo 2024): 111. http://dx.doi.org/10.3390/act13030111.

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Targeting the issue of high losses of individual switching tubes in Neutral-Point Clamped (NPC) three-level inverters, an Active Neutral-Point Clamped (ANPC) three-level inverter is used, and a model predictive control strategy using the loss equalization of the inverter is proposed. This method organizes and analyzes multiple zero-state current pathway commutation modes and adds mode three under the original two commonly used zero-state commutation modes. On this basis, the three modes are flexibly switched by model predictive control, and the output is optimized according to the value function for the space vector in each operation, while the midpoint voltage control is added to the value function. The simulation results suggest that the recommended strategy in this study may effectively realize the loss equalization control and midpoint voltage control of the ANPC inverter, which improves the operation efficiency of the electromechanical actuator.

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AbolqasemiKharanaq, Fatemeh, Amirreza Poorfakhraei, Ali Emadi e Berker Bilgin. "An Improved Carrier-Based PWM Strategy with Reduced Common-Mode Voltage for a Three-Level NPC Inverter". Electronics 12, n. 5 (21 febbraio 2023): 1072. http://dx.doi.org/10.3390/electronics12051072.

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Double modulation wave carrier-based pulse width modulation (CBPWM) is a solution for eliminating the deviations of the neutral-point voltage (NPV) in three-level neutral-point clamped inverters. In this paper, a new hybrid CBPWM strategy is proposed that not only eliminates the neutral-point voltage oscillations but also reduces the common-mode voltage (CMV) by half. Furthermore, the harmonic content is also reduced compared with the available reduced CMV modulation by adjusting the modulation waves based on the location of the reference vector in the space vector diagram. An active neutral-point voltage controller is also realized in order to maintain the performance of the modulation strategy under the NPV perturbations. The performance of the proposed algorithm is compared to the available CBPWM-based techniques in the literature. The effectiveness of the proposed method is also verified by experimental results.

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Thahab, Riyadh Toman, Tahani Hamodi Al-Mhana e Ahmed Toman Thahab. "Capacitor current analysis of a three-level neutral point clamped converter under unbalanced loading conditions". International Journal of Electrical and Computer Engineering (IJECE) 13, n. 6 (1 dicembre 2023): 6156. http://dx.doi.org/10.11591/ijece.v13i6.pp6156-6173.

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A neutral point clamped (NPC) converter is considered a forefront in industrial applications. Supplying a typically balanced stand-alone load is one of those applications. However, the loading may become unbalanced which can impact the capacitors’ current and voltage ripple. In this work, an approach is proposed that analyze the capacitor current under unbalanced loading. The proposed method is based on a combination of two-dimensional Fourier series and symmetrical components. Since, two-dimensional Fourier series sectorize the spectrum into harmonics that are either defined by multiples of, fundamental, carrier or both frequencies, the method derives the Fourier coefficients for each sector, corresponding to a sequence current. Therefore, based on the presented approach, each harmonic amplitude in the spectrum sector is defined by three Fourier coefficients reflecting zero, positive and negative sequence current. The capacitor current spectrum is obtained by vector summing sequence coefficients. The method is tested on unbalanced load conditions with (out) a ground path. Results verify feasibility of the proposed method in deriving Fourier coefficients of capacitor currents that accurately reflects the loading status of the NPC. This is vital for converter design in terms of proper sizing of DC capacitor and can help in avoiding components failure.

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Omri, Bassem, Kaiçar Ammous e Anis Ammous. "Using Averaged Modeling for Capacitors Voltages Observer in NPC Inverter". Advances in Power Electronics 2012 (27 dicembre 2012): 1–11. http://dx.doi.org/10.1155/2012/176876.

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This paper developed an adaptive observer to estimate capacitors voltages of a three-level neutral-point-clamped (NPC) inverter. A robust estimated method using one parameter is proposed, which eliminates the voltages sensors. An averaged modeling of the inverter was used to develop the observer. This kind of modeling allows a good trade-off between simulation cost and precision. Circuit model of the inverter (implemented in Simpower Matlab simulator) associated to the observer algorithm was used to validate the proposed algorithm.

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Wu, Liang, Yong Yang e Zhong Kui Zhu. "A New Technology of Pulse by Pulse for NPC Three-Level Inverters". Advanced Materials Research 765-767 (settembre 2013): 2489–93. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.2489.

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When Neutral Point Clamped (NPC) three-level photovoltaic grid-connected inverter is overloaded or in short state, the control by software could not judge immediately, but the power switch components of the inverter would be broken. The technology of Pulse by Pulse is an important method to protect the power switch components. This paper studies the principle of traditional technology of Pulse by Pulse, then analyzes a new technology of Pulse by Pulse based on Complex Programmable Logic Device (CPLD), finally a 3KW NPC three-level grid-connected inverter is set up with the new technology of Pulse by Pulse and the feasibility is demonstrated through the experiments.

48

Ma, Zhixun, Haichuan Niu, Xiang Wu, Xu Zhang e Guobin Lin. "An Improved Overmodulation Strategy for a Three-Level NPC Inverter Considering Neutral-Point Voltage Balance and Common-Mode Voltage Suppression". Sustainability 14, n. 19 (2 ottobre 2022): 12558. http://dx.doi.org/10.3390/su141912558.

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The three-level neutral-point clamped voltage source inverter (3L-NPC-VSI) is widely used in the maglev traction systems due to its high output voltage, large output capacity and low output current harmonics. In order to improve the utilization of the DC-bus voltage, an overmodulation strategy is necessary. This paper proposes an improved overmodulation strategy based on the minimum amplitude error method for a 3L-NPC-VSI. Compared with the conventional overmodulation strategy based on the minimum amplitude error method, the utilization of the DC-bus voltage is higher. Meanwhile, a virtual space vector modulation strategy is adopted for inverter neutral-point (NP) voltage balance and common-mode voltage (CMV) suppression. Furthermore, the suppression of leakage current also has been verified. Furthermore, the implementation details of the proposed overmodulation strategy based on minimum amplitude error method is elaborated. The effectiveness of the proposed method is verified by simulation and experimental results.

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Chao, Kuei-Hsiang, e Chen-Hou Ke. "Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives". Energies 13, n. 23 (29 novembre 2020): 6302. http://dx.doi.org/10.3390/en13236302.

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This paper presents an extension theory-based assessment method to perform fault diagnosis for inverters in motor driving systems. First, a three-level neutral-point clamped (NPC) inverter is created using the PSIM software package to simulate faults for any power transistor in the NPC-type inverter. Fast Fourier transformation is used to transform the line current signals in the time domain into a spectrum in the frequency domain for analysis of the corresponding spectrum of features of the inverter for faults with different power transistors. Then, the relationships between fault types and specific spectra are established as characteristics for the extension assessment method, which is then used to create a smart fault diagnosis system for inverters. Fault-tolerant control (FTC) is used here when the rated output of a faulty inverter is decreased in order to maintain balanced output in three phases by changing the framework of the transistor connection. This is performed to reinforce the reliability of the inverter. Finally, by the simulation and experimental results, the feasibility of the proposed smart fault diagnosis system is confirmed. The proposed fault diagnosis method is advantageous due to its minimal use of data and lack of a learning process, which thereby reduces the fault diagnosis time and makes the method easily used in practice. The proposed fault-tolerant control strategy allows both online and smooth switching in the wiring structure of the inverter.

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Khlifi, Mohamed Arbi. "Behavior of a Dual Stator Induction Machine Fed by Neutral Point Clamped Multilevel Inverter". Journal of Energy 2018 (10 ottobre 2018): 1–10. http://dx.doi.org/10.1155/2018/6968023.

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Use of multilevel inverters with induction machines has become popular in most energy conversion and management systems. The present paper discusses the behavior of the dual stator-winding induction machine (DSIM) for the power source, which is a power supply with Neutral Point Clamped (NPC). Multilevel inverter with PWM technique control is analyzed. The DSIM control is obtained by the PWM technique to multicarrier PWM technique and after a comparative study of various characteristics of the DSIM taking into account the different electrical offsets between the two stars (0°, 30°, 60°). The gap between the two stars was considered, and it is impacted on torque and rates harmonic distortion of circulation currents.

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