An adaptive harmonic detection and a novel current control strategy for unified power quality conditioner

This paper proposes an adaptive harmonic detection to precisely detect the voltage with multiple zero crossings and adaptively obtain the reference signals, which makes use of linear neurons to approximate the fundamental component in each phase followed by a symmetric decomposition that calculates the fundamental positive components. According to the compensating requirements, we obtain four different forms of the reference signals. The detected reference signals are then fed into a triangular wave comparison control together with a PI controller and a one cycle current control to force the compensating voltage and current to track the reference signals. The one cycle current control (OCCC) is a combination of the one cycle control and the hysteresis control, which guarantees both tracking performances and constant frequency. The integration of the adaptive detection method and the one cycle current control in a three-phase unified power quality conditioner (UPQC) are simulated, where the effectiveness and reliability of the proposed strategies are demonstrated.