Performance analysis of UPQC with heterogeneous control during load power factor variation

This paper deals with the analysis of a unified power quality conditioner (UPQC) with a new heterogeneous control applied to its active power filters (APF). This control, when applied to the APFs of UPQC, relieves completely the reactive power burden of the source and makes the input power factor unity. The proposed control, termed as heterogeneous control, utilizes sinusoidal pulse width modulation (SPWM) for series APF (SAPF) and hysteresis PWM for parallel APF (PAPF). No transformation is used in this control for generating the reference quantities for both voltage and current. The performance of UPQC with the proposed control is compared with other transformation less homogeneous control schemes which include hysteresis and SPWM for both APFs. The heterogeneous control performance is found superior in terms of complete reactive power support from the PAPF with reduced APF ratings. PSCAD/EMTDC simulation results are presented to show the effectiveness of the proposed control. Copyright (c) 2011 John Wiley & Sons, Ltd.