Approach to eliminate DC-link voltage pulsations of voltage-source PWM rectifier

CHEN Jian-sheng， ZHANG Wei， XV Hai-liang
（College of Electrical Engineering， Zheijiang University， Hangzhou 310027， China）

Abstract： The stability of the DC-link voltage is a main target of the grid-connected PWM rectifier. When the grid voltage is unbalanced and （or）harmonically distorted，the conventional control strategy can’t eliminate the pulsation of DC-link voltage. In order to solve this problem，Firstly，the effect of unbalanced and 5th and 7th harmonics to the VSR was analyzed；and then，an approach based on PI-R controller was proposed，with detail calculation of the current references and designation of current controller. Simulation results of a 1 MW VSR indicate that the proposed control strategy can significantly reduce the DC-link voltage pulsation，enhance the operation of the DC-link capacitor and the associated load safely.
Key words： voltage-source PWM rectifier（VSR）； harmonic distortion； proportional integral plus resonant（PI-R） controller； DC-link voltage