A Novel UPQC Topology with Medium Frequency Isolation for Distribution Power Systems

This paper proposes a novel unified power quality conditioner (UPQC) topology based on a quadruple-CLLC (Q-CLLC) resonant converter. Unlike the conventional UQPC topologies, the proposed topology eliminates the bulky low-frequency transformer. The isolation is provided by a multi-winding medium-frequency transformer which reduces the weight and volume of the UPQC. Another benefit that can be obtained by using the proposed topology is a decoupled operation between each phase for the series compensator. Thus, the UPQC can still be operated if one of the series compensators requires maintenance. The UPQC can be used to compensate all types of disturbances such as voltage sag/swell, power factor correction, and voltage/current distortion. The effectiveness of the proposed UPQC topology has been verified by simulation results at medium voltage level (6.6 kV).