A current control scheme based on multiple synchronous reference frames for parallel hybrid active filter

A control algorithm is developed with the objective of eliminating the harmonics and reactive power for the parallel hybrid active filters. In this problem set, the load current is assumed to have the 5th and 7th harmonics along with the fundamental component. We utilize the three synchronous reference frames (SRF) and the low pass filters to measure the fundamental, 5th, 7th components separately. In the SRF rotation at the fundamental frequency, the q-axis current is controlled to regulate the reactive power and d-axis current is controlled to keep constant the DC link voltage of the converter. In the SRF´s rotation at the frequencies of 5th and 7th harmonics, the filter currents are controlled to cancel out the 5th and 7th harmonics of the load. In each controller the cross-coupling current control scheme is utilized for decoupling d-q current dynamics interaction