scholarly journals A New Bidirectional Three-phase Neutral Point Clamped (NPC) Grid-Connected Converter: Analysis and Simulation

2021 ◽  
Author(s):  
Christel E. G. Ogoulola ◽  
Angelo J. J. Rezek ◽  
Robson B. Gonzatti ◽  
Vinicius Z. Silva ◽  
Marcos L. Ramos ◽  
...  

This paper deals with the theoretical development, analysis, and simulation of the new topology of three-phase NPC (Neural Point Clamped) converter. The proposed 6-kW three-phase converter is connected to a three-phase electrical network and due to its bidirectional characteristics can either send energy to the grid or receive it from the grid. The classic strategy of vectorial control at the DQ synchronous reference frame, along with a simple algorithm for Unit Vector Generation (UVG), have been employed to control the line currents in the grid and the DC-bus voltage, thus substituting the PLL (Phase Locked Loop). A PWM (Pulse Width Modulation) strategy is presented in the form of an analog circuit and used for switching the semiconductors in the converter. The obtained results were verified using Matlab/Simulink software. The proposed converter has five voltage levels at the output for each phase and proven more advantageous than the conventional NPC. In addition, it was obtained a better harmonic content in the grid currents because there is very low Total Harmonic Distortion (THD) both when acting as a rectifier and as an inverter.

Author(s):  
Olwi A. Elkholi ◽  
Mohamed A. Enany ◽  
Ahmed F. Abdo ◽  
Mahmoud Eid

<p class="Abstract">Due to their better DC bus utilization and easier digital realization, Space Vector Pulse Width Modulation (SVPWM) scheme is the most widely used PWM scheme. Also two level inverter is the traditional frequency converter because it has fewer components and is lower complex to control, but on the other hand it generates higher harmonic distortion. This paper presents the realization of novel SVPWM approaches applied to the three phase induction motor drives. Specifically various schemes are based on using more combinations of step operation in each cycle to approximate the reference vector, such as 24 and 48 step operations in each cycle. The basic principle of conventional SVPWM with different modulation index M is presented. The switching sequences of new approaches are described. The modulation signals waveforms, DC bus voltage utilization, De-rated motor torque, standard error of average torque, voltage and current harmonic of new approaches are analyzed by the MATLAB/SIMULINK software. The results confirms that 48 step SVPWM approach is the best compared to other approaches.</p>


Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 234 ◽  
Author(s):  
Ahmet Aksoz ◽  
Yipeng Song ◽  
Ali Saygin ◽  
Frede Blaabjerg ◽  
Pooya Davari

In this paper, a virtual positive impedance (VPI) based active damping control for a slim DC-link motor drive with 24 section space vector pulse width modulation (SVPWM) is proposed. Utilizing the proposed control and modulation strategy can improve the input of current total harmonic distortion (THD) while maintaining the cogging torque of the motor. The proposed system is expected to reduce the front-end current THD according to international standards, as per IEC 61000 and IEEE-519. It is also expected to achieve lower cost, longer lifetime, and fewer losses. A permanent magnet synchronous motor (PMSM) is fed by the inverter, which adopts the 24 section SVPWM technique. The VPI based active damping control for the slim DC-link drive with/without the 24 section SVPWM are compared to confirm the performance of the proposed method. The simulation results based on MATLAB are provided to validate the proposed control strategy.


Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anbarasan P. ◽  
Krishnakumar V. ◽  
Ramkumar S. ◽  
Venkatesan S.

Purpose This paper aims to propose a new MLI topology with reduced number of switches for photovoltaic applications. Multilevel inverters (MLIs) have been found to be prospective for renewable energy applications like photovoltaic cell, as they produce output voltage from numerous separate DC sources or capacitor banks with reduced total harmonic distortion (THD) because of a staircase like waveform. However, they endure from serious setbacks including larger number of capacitors, isolated DC sources, associated gate drivers and increased control difficulty for higher number of voltage levels. Design/methodology/approach This paper proposes a new three-phase multilevel DC-link inverter topology overpowering the previously mentioned problems. The proposed topology is designed for five and seven levels in Matlab/Simulink with gating pulse using multicarrier pulse width modulation. The hardware results are shown for a five-level MLI to witness the viability of the proposed MLI for medium voltage applications. Findings The comparison of the proposed topology with other conventional and other topologies in terms of switch count, DC sources and power loss has been made in this paper. The reduction of switches in proposed topology results in reduced power loss. The simulation and hardware show that the output voltage yields a very close sinusoidal voltage and lesser THD. Originality/value The proposed topology can be extended for any level of output voltage which is helpful for sustainable source application.


2020 ◽  
Vol 13 (5) ◽  
pp. 176-182
Author(s):  
D. Manikanta Swamy ◽  
M. Venkatesan ◽  
M. Subbarao

In recent years, a Multilevel Inverter (MLI) topology is highly preferred in the various renewable energy applications for converting power due to their merits. In this paper, a three-phase inverter has been designed for grid-connected applications using Proportional Integral (PI) current controller scheme. To generate a sequence, the Level shift (LS) and Phase Shift (PS) Pulse Width Modulation (PWM) methodologies are adapted. This topology has been designed with two stages: the DC-DC conversion stage and DC-AC conversion stage. The DC-DC conversion stage is used to enrich input DC voltage which is obtained from the solar PV array. The PI current controller has been designed to regulate the grid current with park transformation. The performances of the inverter have been examined in terms of Total Harmonic Distortion (THD) using different PWM techniques and also investigated with existing research works. The developed results are verified using MATLAB/ Simulink.


Author(s):  
Mohamed Ali Moussa ◽  
Bachir Belmadani ◽  
Ahmed Wahid Belarbi ◽  
Rachid Taleb

<p>This document is a contribution to improve the quality of electrical energy in the distribution network.<br />In this article we will present a method that allows us to clean up in a very considerable way the electrical network of both harmonics and inter harmonics provoked, basically by the ultrafast switches used when controlling a PWM inverter supplying a three-phase asynchronous motor. We notice that this method can be generalized for other loads creating inter-harmonics.<br />This proposed method was simulated using the MATLAB/SIMULINK software and had given remarkable results (there is a considerable reduction in total harmonic distortion (THD) of source current from 29.52% to 0.82%)</p>


2019 ◽  
Vol 3 (1) ◽  
pp. 21-27
Author(s):  
Francis Mulolani ◽  
Francis Kafata ◽  
Esau Zulu

This paper presents the design and closed-loop current control of a grid connected seven-level, 3-phase diode-clamped multilevel inverter for Photovoltaic (PV) applications. The proposed closed loop current control technique is based on the voltage-oriented proportional integral (PI) controller theory. The modulation technique used is level-shifted-carrier sinusoidal pulse width modulation (SPWM). The gain values of PI controller were selected to achieve good current quality and dynamic response. Grid synchronization was achieved by using a synchronous-reference frame phase-locked loop (SRF-PLL). Matlab/Simulink was used for the control system design and simulation. The simulation results show that a 1.34% total harmonic distortion (THD) of the output current was achieved which is within the allowable current distortion limits by international standards. The stability of the system was analyzed using pole-zero mapping and root locus.


2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Peng Wu ◽  
Lei Yuan ◽  
Zhen Zuo ◽  
Junyu Wei

For six-phase permanent-magnet synchronous motor (PMSM) which has two sets of Y-connected three-phase windings spatially phase shifted by 30 electrical degrees, to increase the utilization ratio of the DC bus voltage, a novel space vector pulse width modulation (SVPWM) algorithm in full modulation range capability based on vector weighted method is proposed in this paper. The basic vector action time of SVPWM method is derived in detail, employing vector space decomposition transformation approach. Compared with the previous algorithm, this strategy is able to overcome the inherent shortcomings of the four-vector SVPWM, and it achieves smooth transitions from linear to overmodulation region. Simulation and experimental analyses demonstrate the effectiveness and feasibility of the proposed strategy.


Author(s):  
Mohammed Rasheed ◽  
Rosli Omar ◽  
Marizan Sulaiman ◽  
Wahidah Abd Halim

<p>In this work, a three-phase of multilevel inverter (MLI) with reduced number of switches components based on Newton Raphson (NR) and Particle Swarm Optimization (PSO) techniques were presented. The Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is a powerful technique for harmonic minimization in multilevel inverter within allowable limits. NR and PSO techniques were used to determine the switching angles by solving the non-linear equation's analysis of the output voltage waveform of the modified CHB-MLI in order to control the fundamental component. A comparison has been made between NR and PSO techniques related to optimization in order minimize harmonic distortion. The main aims of this paper cover design, modeling, construction the modified topology of the CHB-MLI for a three phase five levels inverter. The controllers based on NR and PSO were applied to the modified multilevel inverter. The inverter offers much less THD using PSO scheme compared with the NR scheme. The performance of the proposed controllers based on NR and PSO techniques done by using MATLAB/Simulink of results are compared.</p>


Author(s):  
Mohammed Rasheed ◽  
Rosli Omar ◽  
Marizan Sulaiman ◽  
Wahidah Abd Halim ◽  
Moataz M.A. Alakkad

This paper confers an investigation of a Selective Harmonic Elimination (SHE) technique has gained wide acceptance for many AC drive applications, due to a higher DC bus voltage utilization (higher output voltage compared with the Sinusoidal Pulse Width Modulation (SPWM), lower harmonic distortions and easy digital realization.” In recent years, the SHE technique was extensively adopted in multilevel inverters since it offers greater numbers of switching for obtaining further improvements of AC drive performances. “Nevertheless, the use of SHE-associated multilevel inverters will optimize the switching angles based on Artificial Neural Networks (ANN) compared with Particle Swarm Optimization (PSO) to reduce the Total Harmonic Distortion (THD) of the modified CHB-MLI output voltage within permissible limits. The main objectives of this paper are the design and testing of the CHB-MLI modified topology laboratory for a nine-level single-phase prototype.” Also demonstrated were the experimental effects of using Digital Signal Processing (DSP) TMS320F2812 into a prototype. The controls were applied to the modified multilevel inverter, based on ANN and PSO. The proposed controller was then coded onto a board of DSP TMS320F2812. Compared with the PSO method, the inverter gives fewer THD using ANN scheme.


Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 677 ◽  
Author(s):  
Fermín Barrero-González ◽  
Carlos Roncero-Clemente ◽  
María Isabel Milanés-Montero ◽  
Eva González-Romera ◽  
Enrique Romero-Cadaval ◽  
...  

The boost feature that characterizes Z-source and quasi-Z-source converters is usually achieved by means of a proper insertion of short-circuit states in the full DC-link. In this work, a novel pulse width modulation carrier-based strategy for a three-phase, three-level T-type, quasi-Z-source inverter is introduced, based on the addition of alternate short-circuits in the two halves of the DC-link bus. This technique achieves better performance, less electromagnetic interference, and lower harmonic distortion of the output line-to-line voltage compared to the traditional methods based on the full DC-link shoot-through. At the same time, generating the switching states is to easy implement. The proposed strategy permits the use of electronic devices with lower blocking voltage capability, thus improving converter reliability, size, and cost. The new method may be implemented in another multilevel inverter with an impedance-source network as well. A comprehensive simulation study is performed in order to validate the adopted method, with different inverter input voltages, which is taken as representative of a photovoltaic array. Comparisons are conducted with conventional strategy insertions using the same topology in order to show the improvements achieved.


Sign in / Sign up

Export Citation Format

Share Document