A voltage fluctuation compensation control strategy at DC side for integrated power quality control device

Abstract

The power quality control process in the integrated power quality control device, especially for three-phase unbalance control, usually leads to the capacitor voltage fluctuations on DC side. In rectifier control strategy, the output of the voltage loop is the reference value of the inner current loop, and the DC-side voltage is the reference value of the voltage loop. Therefore, the DC-side voltage instability will overlay a fluctuating component on the reference value, which affects the accuracy of the inner current loop control, causing a considerable impact on the transient performance of the integrated power quality control system. Hence, the stability of the DC-side voltage becomes the main factor of the current loop control strategy. Unfortunately, in practical applications, such fluctuations on DC side are inevitable. In this paper, the DC-side capacitor voltage fluctuation mechanism is studied, and a comprehensive power quality control strategy based on feed-forward compensation is proposed to mitigate the DC capacitor voltage fluctuation influence. The proposed compensation control strategy prevents the impact of DC-side voltage fluctuations on the control system. The simulation conducted on the developed experimental platform verified the feasibility and capability of the feed-forward control strategy of the integrated power quality control system.