Journal articles: 'Neutral Point Clamped (NPC) Inverters'

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Pakdel, M., and S. Jalilzadeh. "A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters." Engineering, Technology & Applied Science Research 7, no. 2 (April 24, 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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Edwin Deepak, F. X., and 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, no. 5 (September 5, 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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Guo, Yujing, and Junhuai Zhang. "Modulation Technique Design of An Improved Zero Common Mode Voltage (CMV)." Journal of Physics: Conference Series 2563, no. 1 (August 1, 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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Reusser, Carlos A., and Hector Young. "Four-Level Quasi-Nested Inverter Topology for Single-Phase Applications." Electronics 10, no. 3 (January 20, 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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Suresh Kumar Annam and 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, no. 2 (December 30, 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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Chen, Guo, Chunyang Gong, Jun Bao, Lihua Zhu, and Zhixin Wang. "Compensation-Voltage-Injection-Based Neutral-Point Voltage Fluctuation Suppression Method for NPC Converters." Energies 16, no. 11 (May 30, 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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Chao, Kuei-Hsiang, and Chen-Hou Ke. "Fault Diagnosis and Tolerant Control of Three-Level Neutral-Point Clamped Inverters in Motor Drives." Energies 13, no. 23 (November 29, 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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Doan, Nam Xuan, and Nho Van Nguyen. "Virtual Space Vector Pulse Width Modulation for Asymmetric T-Type Neutral Point Clamped 3-Level Inverter." Mathematical Problems in Engineering 2021 (December 7, 2021): 1–19. http://dx.doi.org/10.1155/2021/1379040.

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This paper proposes a novel 3-phase asymmetric 3-level T-type NPC inverter and studies its PWM performance using a virtual space vector pulse width modulation control strategy. Firstly, the mathematical model and characteristics of this economical topology are described. Then, a virtual space vector approach is proposed to build a space vector diagram for designing SVPWM control. Similar to the conventional 3-level NPC inverter, the asymmetric inverter can also work with the neutral point voltage self-balancing in a fundamental period, which enables employment of this topology in various applications. Finally, simulation and experiment results under different load conditions have shown good output performance of the asymmetric 3-level topology. Similar tests are also performed on both conventional 2-level and 3-level inverters for comparison. For an almost similar number of different voltage vectors in the space vector diagram, the asymmetric 3-level topology can compete with conventional 3-level inverters for low-cost applications. The obvious benefit of the asymmetric 3-level inverter is a smaller number of switches devices while it can achieve output performance similar to that of the conventional 3-level. The comparative investigation also shows that the total loss given by SVPWM for the asymmetric 3-level configuration is lower than that of the traditional 3-level inverter.

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Wang, Lu Jun, Tao Gong, and Jun Zhu. "Robust Predictive Control for NPC Grid-Connected Inverters." Applied Mechanics and Materials 668-669 (October 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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Akbari, Ehsan, and Farhad Zishan. "Modified Topology and Modulation Technique for Z-Source Neutral-Point Clamped Inverter." Power Electronics and Drives 7, no. 1 (January 1, 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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Patrao, Iván, Marian Liberos, Raúl González-Medina, Enric Torán, Emilio Figueres, and Gabriel Garcerá. "Small-Signal Model of the NPC + GCC Multilevel Transformerless Inverter in Single-Phase Photovoltaic Power Systems." Electronics 12, no. 17 (August 22, 2023): 3545. http://dx.doi.org/10.3390/electronics12173545.

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Photovoltaic transformerless inverters are very efficient and economical options for solar-power generation. The absence of the isolation transformer improves the converters’ efficiency, but high-frequency voltage to ground can appear in the photovoltaic string poles. The high capacitance to ground of the photovoltaic generator leads to undesirable high-leakage currents. Using half-bridge topologies dramatically reduces the leakage to ground, and using a multilevel half-bridge inverters improves the output quality compared with classical inverters. The neutral point clamped + generation control circuit (NPC + GCC) topology is a multilevel single-phase transformerless inverter capable of tracking the maximum power point of two photovoltaic sources at the same time. This paper presents the control structure and the dynamic modeling of the NPC + GCC inverter. The pulse-width modulated (PWM) switch model in continuous conduction mode (CCM) was used to obtain the small-signal model of the two switching converters that make up the inverter. The resulting dynamic model was used to quantify the stability margins of both converters’ current and voltage loops.

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Sahu, M. K., A. K. Panda, and B. P. Panigrahi. "Direct Torque Control for Three-Level Neutral Point Clamped Inverter-Fed Induction Motor Drive." Engineering, Technology & Applied Science Research 2, no. 2 (April 11, 2012): 201–8. http://dx.doi.org/10.48084/etasr.117.

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Direct torque control (DTC) is a control technique in AC drive systems to obtain high performance torque control. The classical DTC drive contains a pair of hysteresis comparators and suffers from variable switching frequency and high torque ripple. These problems can be solved by using space vector depending on the reference torque and flux. In this paper the space vector modulation technique is applied to the three-level Neutral Point Clamped (NPC) inverter control in the proposed DTC-based induction motor drive system, resulting to a significant reduce of torque ripple. Three-level neutral point clamped inverters have been widely used in medium voltage applications. This type of inverters have several advantages over standard two-level VSI, such as greater number of levels in the output voltage waveforms, less harmonic distortion in voltage and current waveforms and lower switching frequencies. This paper emphasizes the derivation of switching states using the Space Vector Pulse Width Modulation (SVPWM) technique. The control scheme is implemented using Matlab/Simulink. Experimental results using dSPACE validate the steady-state and the dynamic performance of the proposed control strategy.

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Beriber, D., A. Talha, and M. Boucherit. "Stabilization of multi DC bus link voltages of multilevel NPC VSI. Application to double stator induction motors." Archives of Control Sciences 22, no. 1 (January 1, 2012): 107–20. http://dx.doi.org/10.2478/v10170-011-0015-1.

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Stabilization of multi DC bus link voltages of multilevel NPC VSI. Application to double stator induction motors Voltage source multilevel inverters have become very attractive for power industries in power electronics applications during last years. The main purposes of studying multilevel inverters are the generation of output voltage signals with low harmonic distortion and reduction of switching frequency. An important issue of the multilevel inverter is the capacitor voltage-balancing problem. The unbalance of different DC voltage sources of multilevel neutral point clamped (NPC) voltage source inverter (VSI) constitutes the major limitation for the use of this new power converter. In this paper, we present study on the stability problem of the input DC voltages of the three-level Neutral Point Clamping (NPC) voltage source inverter (VSI). This inverter is useful for application in high voltage and high power area. In the first part, we remind the model of double stator induction motors (DSIM). Then, we develop control models of this inverter using the connection functions of the semi-conductors. We propose a Pulse Width Modulation (PWM) strategy to control this converter. The inverter is fed by constant input DC voltages. In the last part, we study the stability problem of the input DC voltages of the inverter. A cascade constituted by two three-level PWM rectifiers - two three-level NPC VSI - DSIM is discussed. The results obtained show that the input DC voltages of the inverters are not stable. To solve this problem, we propose to use a half clamping bridge. This solution is very promising in order to stabilize the input DC voltages of this converters.

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Shen, Yanxia, Beibei Miao, Dinghui Wu, and Kader Ali Ibrahim. "Fault-Tolerant Control Strategy for Neutral-Point-Clamped Three-Level Inverter." Journal of Control Science and Engineering 2018 (February 1, 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.

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Jayakumar, Vinoth, and Bharatiraja C. "Model Predictive Control of PMSM Motor Drive for Electric Vehicle Applications with Space Vector Modulation." ECS Transactions 107, no. 1 (April 24, 2022): 14465–72. http://dx.doi.org/10.1149/10701.14465ecst.

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The Multi-Level Inverters (MLI) are most predominantly used in industrial applications as they reduce dv/dt ratio, switching stress of the power semiconductor switches, etc. The industries are slowly shifting from three phase inverters to five phase inverters as they produce lower current per phase, less switching losses, low Common Mode Voltage (CMV), etc. The Space Vector Modulation (SVM) is one of the controlling techniques for driving the inverters which reduces the Total Harmonic Distortion (THD) and improves the dc link balancing. The switching vectors available for five phase Three Level (3L) Neutral Point Clamped (NPC) Inverter is 243 vectors, out of which 51 vectors are selected that produce zero CMV. The controlling of the inverter is done by Model Predictive Control (MPC) Technique in which the error is reduced. The performance of the inverter is evaluated through MATLAB Simulink.

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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 (October 10, 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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Wu, Wen-Jie, Liang-Deng Hu, Zi-Yue Xin, and Cheng Guo. "Modeling and Analysis of Voltage Harmonic for Three-Level Neutral-Point-Clamped H-Bridge Inverter Considering Dead-Time." Energies 15, no. 16 (August 16, 2022): 5937. http://dx.doi.org/10.3390/en15165937.

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The advantages of three-level neutral-point-clamped (NPC) H-bridge inverters, such as simple topological structure, low device voltage stress, high equivalent switching frequency, and highly expansible capacity, have made them the preferred choice for inverters matching with medium voltage high-capacity multi-phase open-end winding vessel propulsion motors. To quantitatively evaluate the propulsion motors’ harmonics, electromagnetic vibration, and noise caused by pulse-width modulation (PWM) and device dead-time, it is necessary to research the mathematical modeling of pulse-width modulated output voltage harmonics in consideration of dead-time. In this paper, the principle of the phase-disposition PWM method of the 3L-NPC H-bridge inverters was firstly introduced. Then, the analytical models of output voltage harmonics with and without considering the effect of dead-time were established based on the double Fourier series approach and the harmonic distribution of the dead-time effect was accurately characterized. On the basis of the above, the experimental platform was established to verify the proposed analytical model. Simulation and experimental results are consistent with the theoretical analysis in low and high-frequency output voltage harmonics, which proves the correctness and the feasibility of the analytical modeling method researched by this paper. This will provide a theoretical basis for subsequent studies, which include the quantitative analysis and the suppression of output harmonics of the H-bridge inverter considering dead-time.

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Omri, B., L. Fakhfakh, K. Ammous, and A. Ammous. "Validation of a Nonlinear Average Model of NPC Inverters Based on Experimental Investigations." International Journal of Emerging Electric Power Systems 17, no. 6 (December 1, 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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Almatani, Nawaf O., Abdullah Ali Alhussainy, Sultan Alghamdi, Hossam Kotb, Kareem M. AboRas, Mahendiran Vellingiri, and Muhyaddin Rawa. "Assessment of a High-Order Stationary Frame Controller for Two-Level and Three-Level NPC Grid-Connected Inverters." Energies 15, no. 24 (December 8, 2022): 9313. http://dx.doi.org/10.3390/en15249313.

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Most grid-connected DC/AC inverters use traditional proportional–integral (PI) controllers in a synchronous frame. In addition to poor disturbance rejection capabilities, these PI controllers also exhibit steady-state errors for sinusoidal reference signals. To address these drawbacks, this article investigates the use of a high-order controller in the stationary frame and then compares it with the standard PI controller. The effectiveness of the high-order controller in the stationary frame has been examined by providing an infinite gain at a resonance frequency. In this work, the design of high-order and PI controllers and tuning instructions are given. Furthermore, both high-order and PI current-controlled two-level and three-level neutral point clamped (NPC) inverters are compared. Various operational conditions are used for the comparison. The high-order controller reduced the total harmonic distortion (THD) of the injected current by 1.15% for the two-level inverter in normal conditions as compared to the PI controller and 0.9% for the three-level NPC inverters. Furthermore, it reduced the THD in balanced abnormal conditions by 0.5% for the two-level inverter and 0.18% for the three-level NPC inverters. However, the dq controller has a lower THD during unbalance and short circuit conditions.

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Zaid, Sherif A., Abualkasim Bakeer, Hani Albalawi, Adel M. Alatwi, Hassan Abdeldaim, and Bassel Manqarah. "Model-Free Predictive Current Control of a 3-φ Grid-Connected Neutral-Point-Clamped Transformerless Inverter." Energies 16, no. 7 (March 30, 2023): 3141. http://dx.doi.org/10.3390/en16073141.

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Utility grid-tied photovoltaic (PV) installations are becoming a typical component of the current electrical energy grid. The adoption of transformerless inverters has recently changed the topology of these systems. Despite being small, inexpensive, and effective, transformerless inverters have a recurring leakage current issue. Numerous studies are being conducted to improve its performance and bring the leakage current down to acceptable levels. The studies propose three tracks for addressing the leakage current problem of transformerless PV systems: the control technique, the inverter modulation, and the inverter topology. This study applies the model-free predictive control (MFPC) technique to a grid-connected NPC 3-φ transformerless converter powered by a PV panel. An LCL filter connects the transformerless inverter to the grid. The system model considers the grid filter components and the internal impedance of the utility grid. The proposed system’s discrete model is established before describing the MFPC controller’s algorithm. The suggested system is simulated in MATLAB using the MFPC and a standard PI current controller with SVPWM modulation. According to the simulation’s findings, the MFPC controller performs best regarding current spectrum, THD, and earth leakage current. Additionally, MFPC-based systems are more efficient than those that use PI controllers.

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Zhang, Guozheng, Yingjie Su, Zhanqing Zhou, and Qiang Geng. "A Carrier-Based Discontinuous PWM Strategy of NPC Three-Level Inverter for Common-Mode Voltage and Switching Loss Reduction." Electronics 10, no. 23 (December 5, 2021): 3041. http://dx.doi.org/10.3390/electronics10233041.

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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.

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Ammari, Sakina, Aziza Benaboud, and Mohamed Talea. "PI-based PLL and 24-sector control of a 3P-3L-NPC inverter for grid-tied PV system synchronization." International Journal of Applied Power Engineering (IJAPE) 11, no. 3 (September 1, 2022): 179. http://dx.doi.org/10.11591/ijape.v11.i3.pp179-185.

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This article addresses one of the most serious issues in electricity: frequency and voltage anomalies. Actually, because renewable energy production is intermittent, the frequency and voltage of electricity produced are unstable and dependent on weather conditions. This issue causes industrial processes to fail, affecting the quality of the electrical supply and having a massive economic impact. Power electronics inverters are designed to compensate for system fluctuations in solar power generation. However, measurement noise in the grid voltage desynchronizes the inverter and network signals. The authors propose using a phase-locked loop technique based on inverter period control and a network voltage observer to achieve such synchronization of grid-connected photovoltaic (PV) systems. In this work, the grid integration of the PV system is carried out through a three-phase three-level neutral point clamped inverter due to better current quality with fewer harmonics and lower stress voltage of the inverter's components when compared to two-level voltage source inverters. The method is successfully applied in a simulated case study and experimental results validate it.

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Rehaoulia, Abir. "Voltage THD limits for three- and single-phase multilevel inverters." Journal of Electrical Engineering 73, no. 5 (September 1, 2022): 363–67. http://dx.doi.org/10.2478/jee-2022-0050.

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Abstract This paper deals with single and three phase multilevel inverters power quality. The voltage total harmonic distortion rate is an important criterion for choosing the number of inverter levels and checking compatibility with power quality requirements. In this study, the author raises an interesting issue related to the definition of voltage THD boundaries with upper and lower limits. The problem is reformulated, and a novel and more practical approach is developed for three- and single-phase multilevel inverters. Found upper and lower voltage THD limits are sufficiently verified with most known switching algorithms like sinusoidal modulation (SM) with phase disposition (PD), space vector modulation (SVM) and selective harmonic elimination (SHE). They are also valid for cascaded (H-Bridge), neutral point clamped (NPC) and flying capacitors (FC) multilevel inverters.

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Beniak, Ryszard, Krzysztof Górecki, Piotr Paduch, and Krzysztof Rogowski. "Reduced Switch Count in Space Vector PWM for Three-Level NPC Inverter." Energies 13, no. 22 (November 14, 2020): 5945. http://dx.doi.org/10.3390/en13225945.

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The aim of this paper is to present the real-time implementation and measurements of a reduced switch count in space vector pulse width modulation for three-level neutral point clamped inverters (3L-NPC). We implement space vector pulse width modulation, which uses a prediction algorithm to reduce the number of switches in power transistors (switch count) by up to about 13%. The algorithm applies additional redundant voltage vectors. The method is compute-intensive and was implemented on a dual-core TMS320F28379D digital signal controller. The latest measurements of steady and dynamic states of electric drive, powered by a 3L-NPC inverter using this method, confirmed the possibility of using this method in practical implementation. The implementation and results of the measurements are presented in this paper.

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Rechach, Abdelkrim, Sihem Ghoudelbourk, and Mihoub Mohamed Larbi. "Impact of Choice of Neutral Point Clamped and H-Bridge Multilevel Inverters for PV Systems." European Journal of Electrical Engineering 24, no. 4 (August 31, 2022): 213–19. http://dx.doi.org/10.18280/ejee.240406.

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The exploitation of solar energy and the universal interest in photovoltaic systems have increased nowadays due to galloping energy consumption and current geopolitical and economic issues. This has led to high technical and economic requirements. The PV system still faces major obstacles such as high cost and low efficiency compared to other renewable technologies. In addition, the photovoltaic system suffers from the rate of undesirable harmonics of the generated power which could alter the quality of energy and the performance requested by users. In order to remedy this problem, the use of the multi-level inverter is in these cases one of the most promising solutions. Indeed, the multi-level technology seems to be well suited to photovoltaic applications to help fill the need for several sources on the DC side of the converter. The technical performance and reliability of the multi-level inverter used to connect the PV modules to the electrical power distribution networks can improve and make profitable the power produced. In this work, we compare two multi-level inverter topologies for PV systems: H-Bridge (HB) and Neutral Point Clamped (NPC). The comparison between these inverters is based on the criteria of spectral quality of the output voltage and the complexity of the power circuits.

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Gupta, Shailesh Kumar, Mohammed Arif Khan, Omveer Singh, and avendra Kumar Chauhan. "Pulse Width Modulation Technique for Multilevel Operation of Five-Phase Dual Voltage Source Inverters." Journal Européen des Systèmes Automatisés 54, no. 2 (April 27, 2021): 371–79. http://dx.doi.org/10.18280/jesa.540220.

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To supply five-phase variable speed drives, five-phase voltage source inverters are used. Some of the applications of five-phase variable speed drives are traction, electric & hybrid-electric vehicles, and ship propulsion. Different control systems are available for the controlled output of the five-phase VSI, but space vector pulse width modulation is popular because of its simpler digital implementation. In this paper, the SVPWM schemes have proposed and analyzed for the multilevel operation of a five-phase dual voltage source inverter. The proposed techniques do not contribute a voltage balancing issues such as in multilevel neutral point clamped (NPC) inverters. The author analyzed the performance of five-phase VSI based on THD and fundamental components. Matlab/Simulink model has provided for results verification.

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Wu, Liang, Yong Yang, and Zhong Kui Zhu. "A New Technology of Pulse by Pulse for NPC Three-Level Inverters." Advanced Materials Research 765-767 (September 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.

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Guo, Xiaoqiang, Xuehui Wang, Ran He, and 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.

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Ek-Iam, Kanyarat, and Yuttana Kumsuwan. "Discontinuous Space Vector Modulation Strategy for Three-Level Neutral Point Clamped Inverter." Applied Mechanics and Materials 781 (August 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.

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Mahaboob Basha, S., and M. Kannan. "Open switch fault detection technique of a back-to-back converter using NPC topology for turbine systems." International Journal of Engineering & Technology 7, no. 2.12 (April 3, 2018): 359. http://dx.doi.org/10.14419/ijet.v7i2.12.11351.

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Efficiency is turning into more and more necessary in power electronics. New applications are developed to reduce the consumption of en-ergy. Inverters that supply continuous quality power have vast use in solar energy based applications. For a Wind Turbine Generation sys-tem with neutral-point-clamped (NPC) topology in a back to back converter , good efficiency is provided when operated at high power. In NPC topology totally twelve switches are present. Input current distortion, torsion vibration and output current distortion is caused by open switch fault within NPC inverter and rectifier of the consecutive converter. Wind Turbine Generation systems will be erroneous due to such faults. Open-switch fault detection methodology is necessary for consecutive converters for enhancing the output of Wind Turbine Genera-tion systems. Our proposed work checks NPC rectifier and inverter for outer and inner open switch faults. Additionally for all the possible open-switch faults , a novel open-switch fault detection methodology within the back to back converter has been presented in this paper.

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Xiaoming Yuan and I. Barbi. "Zero-voltage switching for the neutral-point-clamped (NPC) inverter." IEEE Transactions on Industrial Electronics 49, no. 4 (August 2002): 800–808. http://dx.doi.org/10.1109/tie.2002.801064.

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R, Palanisamy, and Vijayakumar K. "Wind-PV Hybrid Energy Source Fed Three Level NPC with Quasi Z Source Network." International Journal of Power Electronics and Drive Systems (IJPEDS) 8, no. 3 (September 1, 2017): 1285. http://dx.doi.org/10.11591/ijpeds.v8.i3.pp1285-1293.

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Multilevel inverters find use in industrial drive applications and grid based power generation. Owing to the increasing power demand and rising conventional generation costs a new alternative in renewable energy source is gaining popularity and acceptance. A Wind-PV hybrid renewable energy source is proposed which increases power reliability and improves standalone generation efficiency. A Quasi Z source network allows inverter shoot through possibility while boosting the dc voltage fed to the Neutral Point Clamped MLI. Simulation results were obtained for two levels VSI and further simulations for 3 level quasi NPC-TLI verified using Matlab Simulink and hardware implementation results verified by using DSP controller

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Albalawi, Hani, and Sherif A. Zaid. "Performance Improvement of a Grid-Tied Neutral-Point-Clamped 3-φ Transformerless Inverter Using Model Predictive Control." Processes 7, no. 11 (November 15, 2019): 856. http://dx.doi.org/10.3390/pr7110856.

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Grid-connected photovoltaic (PV) systems are now a common part of the modern power network. A recent development in the topology of these systems is the use of transformerless inverters. Although they are compact, cheap, and efficient, transformerless inverters suffer from chronic leakage current. Various researches have been directed toward evolving their performance and diminishing leakage current. This paper introduces the application of a model predictive control (MPC) algorithm to govern and improve the performance of a grid-tied neutral-point-clamped (NPC) 3-φ transformerless inverter powered by a PV panel. The transformerless inverter was linked to the grid via an inductor/capacitor (LC) filter. The filter elements, as well as the internal impedance of the grid, were considered in the system model. The discrete model of the proposed system was determined, and the algorithm of the MPC controller was established. Matlab’s simulations for the proposed system, controlled by the MPC and the ordinary proportional–integral (PI) current controller with sinusoidal pulse width modulation (SPWM), were carried out. The simulation results showed that the MPC controller had the best performance for earth leakage current, total harmonic distortion (THD), and the grid current spectrum. Also, the efficiency of the system using the MPC was improved compared to that using a PI current controller with SPW modulation.

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Stranyóczky, L., A. Balogh, Z. Süto, and I. Varjasi. "Development and testing midpoint voltage balance algorithms of three-level inverters." Renewable Energy and Power Quality Journal 21, no. 1 (July 2023): 521–26. http://dx.doi.org/10.24084/repqj21.382.

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Nowadays, the use of inverters is increasing in more and more applications. Environmental awareness is becoming a trend, so more and more people install solar energy systems on their houses, which also require the use of inverters. Higher power levels have led to the emergence of three-level inverters which has opened up new challenges, such as the issue of midpoint voltage balancing. This paper discusses voltage balancing and voltage ripple reduction techniques for three-level inverters with Neutral-Point Clamped (NPC) topology. The balancing is based on injecting zero-sequence voltage component in carrierbased modulation. The viability of the modulation techniques are verified by computer simulation and then tested on hardware.

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Ahn, Kangsoon, Yongseung Oh, Wonseok Oh, and Kyumin Cho. "Independent Upper- and Lower-Arm Switching Scheme Based on Reference Current Polarity for Three-Level NPC Inverters." Energies 14, no. 17 (September 4, 2021): 5535. http://dx.doi.org/10.3390/en14175535.

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This study presents a novel switching scheme for three-level neutral point clamped (NPC) inverters. The proposed switching method independently drives the upper- and lower-arm elements of the inverter based on the polarity information of the reference current. The proposed switching scheme does not require the inclusion of dead-time for each switching, except when the current polarity changes. Therefore, unlike the conventional inverter switching method, dead-time compensation is not needed, and the possibility of an arm-short accident is prevented. In this study, a switching procedure is detailed, and the operation mode analysis of the proposed switching scheme is presented. The effectiveness of the proposed switching method is verified experimentally by application to a grid-connected inverter that requires inverter current control.

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Narasimha Raju, Kuthuri, Chandra Sekhar Obbu, and Ramamoorthy M. "Appropriate Switching State Selection to Avoid Sapacitor Imbalance in Five-Level NPC." International Journal of Power Electronics and Drive Systems (IJPEDS) 9, no. 1 (March 1, 2018): 276. http://dx.doi.org/10.11591/ijpeds.v9.i1.pp276-285.

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An intrinsic problem with neutral point clamped (NPC) multilevel inverters (MLI) is unbalance of capacitor voltage. There are many mitigation techniques well established in the literature to balance the neutral point voltage for 3-level inverter. These techniques employ either Carrier based pulse width modulation (CBPWM), Space vector pulse width modulation (SVPWM) or hybrid of both the PWM techniques. Balancing becomes complicated as the level of the inverter increases due to addition of capacitor junctions. The imbalance in capacitor voltages may cause uneven voltage distribution among switching devices and sometimes may cause failure. It also increases harmonic content in its output waveform. This paper develops new modulation scheme for balancing capacitor voltages for Five-level inverter .The scheme is a hybrid PWM which is a combination of both CBPWM and SVPWM techniques. As per this scheme CBPWM is applied to meet the load demand and at the zero crossings of the reference signal, CBPWM is blocked and for one carrier cycle. During this SVPWM is applied with appropriate switching state selection to neutralize the imbalance in capacitor voltage.

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Kishore, D. Ravi, T. Vijay Muni, B. Srinivas Raja, Mukesh Pushkarna, B. Srikanth Goud, Kareem M. AboRas, and 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 (July 25, 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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Jing, Tao, Andrey Radionov, Alexander Maklakov, and Vadim Gasiyarov. "Research of a Flexible Space-Vector-Based Hybrid PWM Transition Algorithm between SHEPWM and SHMPWM for Three-Level NPC Inverters." Machines 8, no. 3 (September 17, 2020): 57. http://dx.doi.org/10.3390/machines8030057.

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In this paper, one model of flexible space-vector-based hybrid pulse width modulation (HPWM) transition algorithm consisting of selective harmonic elimination pulse width modulation (SHEPWM) and selective harmonic mitigation pulse width modulation (SHMPWM) is applied and examined in a 10kV grid with a three-level neutral point clamped (3L-NPC) grid-connected inverter. These two modulation techniques are used to produce the appropriate firing pulses for 3L-NPC grid-connected inverters in different cases. SHMPWM is adopted to the grid-connected inverters to mitigate the required odd non-triplen harmonics according to the requirements of grid codes EN 50160 and CIGRE WG 36-05, while the firing pulses generated using SHEPWM is used to eliminate the primary low-order odd non-triplen harmonics completely. Meanwhile, one smooth and fast transition scheme is proposed by providing a suitable switching angles set at the transition point. Finally, it is demonstrated and validated by the MATLAB/SIMULINK model that smooth and quick transition is realized and there is no sudden change of current during the transition, as expected. Furthermore, this hybrid PWM technique is universal for different PWM methods based on the specific operating conditions.

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Yong, Yang. "Direct Instantaneous Power Control of Three-level Grid-connected." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 3 (June 1, 2016): 1260. http://dx.doi.org/10.11591/ijece.v6i3.8193.

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Power electronic grid-connected inverters are widely applied as grid interface in renewable energy sources. This paper presents direct instantaneous power control of a three-phase three-level Neutral Point Clamped (NPC) grid-connected inverter in photovoltaic generation systems. The system consists of a PV array, DC/DC converter, three-level NPC LC filter and the grid. In order to achieve maximum power point tracking (MPPT), an adaptive perturb and observe MPPT is used. For balancing the neutral point (NP) voltage, the control scheme through proportional integral (PI) control according to the direction of the NP current based on redundant vector selection is used. Direct instantaneous power control is developed in a rotating synchronous dq reference frame with space vector modulation with improved operation performance study of the positive sequence detector (PSD) plus a synchronous a synchronous reference frame phase-locked loop (PLL) as the synchronization method. The performance of the proposed method is investigated by a grid-connected photovoltaic system with a nominal power of 12kW. The feasibility of the proposed method is verified through experimental results, showing good steady-state and dynamic performance.

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Yong, Yang. "Direct Instantaneous Power Control of Three-level Grid-connected." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 3 (June 1, 2016): 1260. http://dx.doi.org/10.11591/ijece.v6i3.pp1260-1273.

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Power electronic grid-connected inverters are widely applied as grid interface in renewable energy sources. This paper presents direct instantaneous power control of a three-phase three-level Neutral Point Clamped (NPC) grid-connected inverter in photovoltaic generation systems. The system consists of a PV array, DC/DC converter, three-level NPC LC filter and the grid. In order to achieve maximum power point tracking (MPPT), an adaptive perturb and observe MPPT is used. For balancing the neutral point (NP) voltage, the control scheme through proportional integral (PI) control according to the direction of the NP current based on redundant vector selection is used. Direct instantaneous power control is developed in a rotating synchronous dq reference frame with space vector modulation with improved operation performance study of the positive sequence detector (PSD) plus a synchronous a synchronous reference frame phase-locked loop (PLL) as the synchronization method. The performance of the proposed method is investigated by a grid-connected photovoltaic system with a nominal power of 12kW. The feasibility of the proposed method is verified through experimental results, showing good steady-state and dynamic performance.

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Puthiyapurayil, Muhammed Ramees Mullali Kunnontakath, Mohamed Nadir Nasirudeen, Yashkumar A. Saywan, Md Waseem Ahmad, and Hasmat Malik. "A Review of Open-Circuit Switch Fault Diagnostic Methods for Neutral Point Clamped Inverter." Electronics 11, no. 19 (October 2, 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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Gong, Bo, Shanmei Cheng, and Yi Qin. "Simple three-level neutral point voltage balance control strategy based on SVPWM." Archives of Electrical Engineering 62, no. 1 (March 1, 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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Li, Peifei, Lei Zhang, Bin Ouyang, and Yong Liu. "Nonlinear Effects of Three-Level Neutral-Point Clamped Inverter on Speed Sensorless Control of Induction Motor." Electronics 8, no. 4 (April 4, 2019): 402. http://dx.doi.org/10.3390/electronics8040402.

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In the model reference adaptive speed observer, the induction motor supply voltage is used as the input of the reference model. However, measuring the supply voltage complicates the system and increases the cost, so the command voltage calculated by the controller is generally used instead of the actual supply voltage in the drive system. However, due to the nonlinear effects of the inverter, the voltage calculated by the controller is different from the actual supply voltage, resulting in a speed observation deviation. This paper analyzes the multiple effects that cause the three-level neutral-point clamped (TL-NPC) inverter output voltage and command voltage deviation. A voltage deviation compensation measure based on the volt-second balance principle is proposed. In this context, the expression of the rotational speed deviation caused by the voltage deviation is derived rigorously and in detail. Finally, the effectiveness of the voltage compensation measure is verified by experiments. The experimental results are basically consistent with the theoretical derivation expressions. The method and analysis in this paper is applicable to induction motor speed sensorless control systems driven by two-level and other multilevel inverters.

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AbolqasemiKharanaq, Fatemeh, Amirreza Poorfakhraei, Ali Emadi, and Berker Bilgin. "An Improved Carrier-Based PWM Strategy with Reduced Common-Mode Voltage for a Three-Level NPC Inverter." Electronics 12, no. 5 (February 21, 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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Ahmadi, Sajjad, Philippe Poure, Shahrokh Saadate, and Davood Arab Khaburi. "Fault Tolerance Analysis of Five-Level Neutral-Point-Clamped Inverters under Clamping Diode Open-Circuit Failure." Electronics 11, no. 9 (May 3, 2022): 1461. http://dx.doi.org/10.3390/electronics11091461.

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Multilevel inverters are increasingly used in industrial applications in which service continuity is crucial. This paper presents an original approach to ensure the fault-tolerant operation of neutral-point-clamped (NPC) inverters in the case of an open-circuit fault event in a clamping diode, which is rarely investigated in the conducted research work. The proposed fault-tolerant strategy meets the following criteria: restoring rated output voltage and current during post-fault operation, realizing fault-tolerant operation without additional components, maintaining rated total harmonic distortion (THD) during fault-tolerant operation, and fast transition between faulty operation and remedial operation. In the proposed approach, prior to applying the appropriate remedial action, identification of the defective clamping diode is required. In this respect, a very fast and simple logic-based fault diagnosis is presented whose implementation does not need any additional components and external circuit. Moreover, it does not require any component modeling and complicated calculations. The proposed strategy is validated by simulation and experimentation.

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Enjeti, P. N., and R. Jakkli. "Optimal power control strategies for neutral point clamped (NPC) inverter topology." IEEE Transactions on Industry Applications 28, no. 3 (1992): 558–66. http://dx.doi.org/10.1109/28.137436.

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R, Palanisamy, and 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, no. 3 (March 1, 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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Madasamy, P., Rajesh Verma, A. Rameshbabu, A. Murugesan, R. Umamageswari, Josiah Lange Munda, C. Bharatiraja, and Lucian Mihet-Popa. "Neutral Point Clamped Transformer-Less Multilevel Converter for Grid-Connected Photovoltaic System." Electronics 10, no. 8 (April 19, 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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Selvabharathi, D., Palanisamy R, K. Selvakumar, V. Kalyanasundaram, D. Karthikeyan, Amal Nair, Kriti Karnavat, and Annanya Sharma. "Simulation of Zeta Converter Based 3-level NPC Inverter with PV System." Indonesian Journal of Electrical Engineering and Computer Science 12, no. 1 (October 1, 2018): 1. http://dx.doi.org/10.11591/ijeecs.v12.i1.pp1-6.

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This paper proposes increasing the efficiency of the autonomous Photovoltaic (PV) system by utilizing zeta converter alongside neutral point clamped multilevel inverters (NPC-MLI) based on innovative PWM scheme. The PV system acts as an input source and the relevant control of zeta converter through maximum power point tracking (MPPT) offers the maximum available power from the PV array connected to DC-link. To obtain a high voltage gain we need to exhaust the dc-link voltage as much as possible and reduce stress on the switches. For this the NPC-MLI algorithm approaches PWM technique to perform capacitive charging in parallel and discharging in series to obtain maximum voltage gain. The proposed scheme is designed and verified via detailed simulations in the MATLAB/Simulink environment.

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Benioub, Rabie, Laid Kadri, Mohamed Adnane, and 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, no. 4 (August 1, 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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Journal articles on the topic 'Neutral Point Clamped (NPC) Inverters'

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