Optimized current control and dynamic coordination strategy for large-capacity harmonic compensation system

Multi-modular active power filter has advantages in compensating harmonic current, which results from its controllability and dynamic response performance. However, to realize a reliable and high-precision harmonic compensation system, current control and dynamic coordination strategy need to be optimized. In this paper, centralized current loop is optimized with amplitude and phase correction based on comprehensive analysis of the single PI current loop and selective harmonic detection under multiple rotating reference frame. An improved current-limiting strategy with harmonic frequency priority setting is proposed, which will improve the operation reliability and compensation capacity utilization. In addition, based on the proposed harmonic current control and current-limiting strategy, this paper presents dynamic coordination strategy for large-capacity harmonic compensation system. The proposed strategy determines operating mode according to the component of harmonic current. A novel parallel topology for modular active power filter combining two traditional topologies is used. Finally, the simulation waveforms and experiment results verify the reasonability of the proposed topology and control strategy.