Research on paralleled three-phase four-leg voltage source inverters based on dual-loop control in αβo coordinate

Abstract

This paper presents a dual-loop control scheme in coordinates for paralleled three-phase four-leg voltage source inverters. Using --coordinate, output voltages of the inverter can be controlled in each channel ( ) independently as the voltage component in relating to the inductor in the fourth leg only exists in o-channel. The use of interleaving for paralleled three-phase four-leg inverter would contribute to harmonic cancellation. For control loop, a proportional-resonant regulator in the outer loop and a proportional regulator in the inner loop are incorporated. Meanwhile a state observer for estimating the output voltage and inductor current in each channel is introduced to compensate one time-step delay of the system. The performance of proposed control scheme is verified by experimental results.Index Terms--Four-leg inverter, proportional-resonant regulator, interleaving method, state observer

A Review of Control Techniques and Energy Storage for Inverter-Based Dynamic Voltage Restorer in Grid-Integrated Renewable Sources

“…abc to dq0 Transform PR - [180,181] PR PR [182] PR P [183] dqo frame and stationary frame Integral -3D SVPWM [184] dqo frame PI P SPWM [185,186] PI PI [187] PID and PD - [188,189] PI PI 3D SVPWM [190] PI PI [191] PI and resonant - [192] State feedback - [193] Pole-placement -- real power which affects the rating of direct energy storage or energy received from the grid; hence, the requirement of energy source to supply active power will increase apart from reactive power injected by the inverter. It is acceptable for both balanced and unbalanced sensitive loads heaving phase jump or not.…”

Analysis and implementation of a finite‐control‐set by using model solution‐based control for three‐phase VSI

“…The control schemes for three-phase converters may be classified according to the implemented frame in the process [1,2]. Some schemes work with the αβ-frame [2][3][4]; others operate with the dqframe [5][6][7][8]; and finally, the abc-frame is also suggested [9][10][11][12][13][14]. The frame does not depend on the kind of implemented control; generally, it may be linear or non-linear.…”

“…1 a , which employs a classical proportional–integral (PI) controller and a traditional sinusoidal pulse‐width modulation (SPWM). A scheme based on αβ ‐coordinates, which consider a dual‐loop control scheme, is also found reported in the literature [3]. Even though it offers good performance at the steady state, its transient response is around 3 ms, and a sophisticated digital platform is required for its implementation.…”