Voltage Disturbance Compensator based Control Strategy for Three-phase Voltage Source Converter

Abstract

For three-phase voltage source pulse width modulation (PWM) converter, there is existing distortion in the grid currents and exhibiting fluctuation in the DC bus voltage under inner-loop voltage disturbance. In this paper, a robust control strategy based on voltage disturbance compensator (VDC) is introduced into the double closed-loop control structure to suppress the current distortion and voltage fluctuation. The design and compensation mechanism of the VDC is presented. The stability of the system is analyzed by investigating the real and imaginary part of the closed-loop poles. Simulation and experiments are carried out to validate the proposed control strategy. The results indicate that the three-phase voltage source PWM converter shows a strong robustness under external disturbance when the proposed VDC is applied. Compared with the traditional PI control strategy, it is found that grid currents are highly sinusoidal and DC bus voltage has small fluctuation with the proposed control strategy.