scholarly journals SOGI-based Flexible Grid Connection of PV Power Three Phase Converters under Non-ideal Grid Conditions

2020 ◽  
Vol 10 (1) ◽  
pp. 5195-5200
Author(s):  
R. Abbassi
Keyword(s):  
Current System ◽  
Voltage Source ◽  
Voltage Fluctuations ◽  
New Approach ◽  
Grid Connection ◽  
Three Phase ◽  
Zero Sequence ◽  
Bus Voltage ◽  
Unbalanced Grid

This paper proposes a control strategy of improving the power quality of the energy exchanged between a photovoltaic generator (PVG) and an unbalanced grid. A voltage source inverter (VSI) allowing the control of the zero-sequence during unbalanced regimes is proposed. A Second-Order Generalized Integrators-Based Approach (SOGI-BA), which suitably fits with the network's imbalances while ensuring the perfect isolation of the PVG from the adverse effects of the imbalance, is investigated. The investigation will focus mainly on three control objectives: the generation of a balanced current system, the active and reactive power's dependent control, and the elimination of the second frequency DC bus voltage fluctuations. The performance of this new approach is approved by various tests via MATLAB environment simulations.

scholarly journals A novel power inverter for switched reluctance motor drives

2005 ◽  
Vol 18 (3) ◽  
pp. 453-465 ◽  
Author(s):  
Zeljko Grbo ◽  
Slobodan Vukosavic ◽  
Emil Levi
Keyword(s):  
Switched Reluctance Motor ◽  
Voltage Source ◽  
Power Electronic ◽  
Switched Reluctance ◽  
Three Phase ◽  
Reluctance Motor ◽  
Converter Topology ◽  
Dc Bus ◽  
Bus Voltage ◽  
Power Electronic Converter

Although apparently simpler, the SRM drives are nowadays more expensive than their conventional AC drive counterparts. This is to a great extent caused by the lack of a standardised power electronic converter for SRM drives, which would be available on the market as a single module. A number of attempts were therefore made in recent times to develop novel power electronic converter structures for SRM drives, based on the utilization of a three-phase voltage source inverter (VSI), which is readily available as a single module. This paper follows this line of thought and presents a novel power electronic converter topology for SRM drives, which is entirely based on utilization of standard inverter legs. One of its most important feature is that both magnetizing and demagnetizing voltage may reach the DC-bus voltage level while being contemporarily applied during the conduction overlap in the SRM adjacent phases. At the same time, the voltage stress across the power switches equals the DC-bus voltage. The topology is functional in all operating regimes of the drive. Principle of operation is explained in detail for a three-phase SRM drive and experimental results obtained with a 6/4 switched reluctance motor, are included. Four inverter legs are required in this case. Some considerations, justifying the proposed converter topology from the point of view of the cost, are included.

scholarly journals A Control Strategy for Suppressing Zero-Sequence Circulating Current in Paralleled Three-Phase Voltage-Source PWM Converters

2020 ◽  
Vol 10 (5) ◽  
pp. 1703 ◽  
Author(s):  
Zhao Han ◽  
Xiaoli Wang ◽  
Baochen Jiang ◽  
Jingru Chen
Keyword(s):  
Control Strategy ◽  
Voltage Source ◽  
Duty Ratio ◽  
Phase Voltage ◽  
Pwm Converters ◽  
Circulating Current ◽  
Three Phase ◽  
Zero Sequence ◽  
The Difference ◽  
Zero Vector

In microgrids, paralleled converters can increase the system capacity and conversion efficiency but also generate zero-sequence circulating current, which will distort the AC-side current and increase power losses. Studies have shown that, for two paralleled three-phase voltage-source pulse width modulation (PWM) converters with common DC bus controlled by space vector PWM, the zero-sequence circulating current is mainly related to the difference of the zero-sequence duty ratio between the converters. Therefore, based on the traditional control ideal of zero-vector action time adjustment, this paper proposes a zero-sequence circulating current suppression strategy using proportional–integral quasi-resonant control and feedforward compensation control. Firstly, the dual-loop decoupled control was utilized in a single converter. Then, in order to reduce the amplitude and main harmonic components of the circulating current, a zero-vector duty ratio adjusting factor was initially generated by a proportional–integral quasi-resonant controller. Finally, to eliminate the difference of zero-sequence duty ratio between the converters, the adjusting factor was corrected by a feedforward compensation link. The simulation mode of Matlab/Simulink was constructed for the paralleled converters based on the proposed control strategy. The results verify that this strategy can effectively suppress the zero-sequence circulating current and improve power quality.

Harmonics control of three phase voltage source inverter with random carriers and modified reference

2021 ◽  
pp. 002072092199659
Author(s):  
R Anand ◽  
L Padmasuresh ◽  
P Muthukumar ◽  
P Sreeja ◽  
V Krishnakumar ◽  
...  
Keyword(s):  
Motor Drives ◽  
Voltage Source ◽  
Spectral Quality ◽  
Phase Voltage ◽  
Voltage Source Inverter ◽  
Middle Portion ◽  
Induction Motor Drives ◽  
Three Phase ◽  
Experimental Values

The Harmonics control of any inverters can be decided by the PWM incorporated for the switches. In recent years the carrier and reference modification based research is going on the inverter field. This paper suggests that the alteration of carriers and references of the three phase voltage source inverter enhance the ability to decrease the harmonic content.This enhanced realization deals with the carrier and reference modification arrangement for three phase voltage source inverter through amalgamating the boosted reference and random triangular carrier. The boosted reference is the addition of sine reference with injection of 1/3rd of reference amplitude (3fs) in the middle portion of the reference wave. i.e., [Formula: see text] to [Formula: see text] and [Formula: see text] to [Formula: see text] . The proposed PWM scheme use two carriers, one is Triangle wave and another one is inverted Triangle wave. The process of selecting the winning carrier among the two triangle carriers is purely based on the LFSR technique. The spectral quality of the induction motor drives has improved by the random carriers. The simulation and experimental values are proving the validity of the PWM method. The PWMs are generated by using parallel processing enabled FPGA processor.

Current predictive control of three-phase voltage source PWM rectifiers under unbalanced grid voltage conditions

2016 ◽  
Vol 39 (7) ◽  
pp. 976-986
Author(s):  
Meng Wang ◽  
Yanyan Shi ◽  
Zhen Qi ◽  
Minghui Shen
Keyword(s):  
Predictive Control ◽  
Control Strategy ◽  
Voltage Source ◽  
Phase Voltage ◽  
Two Phase ◽  
Grid Voltage ◽  
Three Phase ◽  
Pwm Rectifiers ◽  
Current Error ◽  
Unbalanced Grid

To improve the performance of three-phase voltage source pulse-width modulated (PWM) rectifiers (VSR) under unbalanced grid voltage conditions, a fixed-frequency current predictive control (CPC) strategy is presented. Instantaneous power of the three-phase VSR is analysed in a two-phase stationary frame. The calculation method for the reference current is improved to achieve the power stability at the AC side of the rectifier. Based on the current predictive model, the optimal duration of the voltage vectors is computed under the restricted condition of minimizing current error at α- and β-axes in fixed intervals. The control system is free of synchronous rotation coordinate transformation, and avoids positive and negative sequence decomposition, which simplifies the calculation. The simulation and experimental results show that the proposed control strategy is able to eliminate the AC current distortion effectively and depress DC link voltage fluctuation under unbalanced grid voltage. Furthermore, the control strategy has faster dynamic response ability, enhancing the control performance of the three-phase VSR system.

scholarly journals Vector Weighting Approach and Vector Space Decoupling Transform in a Novel SVPWM Algorithm for Six-Phase Voltage Source Inverter

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Peng Wu ◽  
Lei Yuan ◽  
Zhen Zuo ◽  
Junyu Wei
Keyword(s):  
Vector Space ◽  
Pulse Width Modulation ◽  
Permanent Magnet Synchronous Motor ◽  
Voltage Source ◽  
Phase Voltage ◽  
Three Phase ◽  
Action Time ◽  
Previous Algorithm ◽  
Bus Voltage ◽  
Smooth Transitions

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.

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