Adaptive DC-Link Voltage Control Technique for HAPF in Reactive Power Compensation

Abstract

This chapter presents a novel adaptive dc-link voltage control technique for hybrid active power filter (HAPF) in reducing switching loss and switching noise under reactive power compensation. The mathematical relationship between HAPF dc-link voltage and reactive power compensation range is initially deduced and presented. Based on the compensation range analysis, the required minimum dc-link voltage with respect to different loading reactive power is deduced. Then an adaptive dc-link voltage controller for the three-phase four-wire HAPF is proposed, in which the dc-link voltage as well as the reactive power compensation range can be adaptively changed according to different inductive loading situations. Therefore, the compensation range, switching loss, and switching noise of the HAPF can be determined and reduced correspondingly. In this chapter, the reference dc-link voltage is classified into certain levels for selection in order to alleviate the problem of dc voltage fluctuation caused by its reference frequent variation, and hence reducing the fluctuation impact on the compensation performances. Finally, representative simulation and experimental results of a three-phase four-wire center-split HAPF are presented to verify the validity and effectiveness of the proposed adaptive dc-link voltage controlled HAPF in dynamic reactive power compensation.