A new topology and coordinated control strategy of power quality conditioner based on time-sharing multiplexing integrated converter

Owing to their advanced comprehensive treatment capabilities, the unified power quality conditioner (UPQC) composed of series and parallel parts has attracted much attention. However, most existing UPQCs suffer from disadvantages, such as low utilization of series parts, high converter capacity and high cost. To address these issues, a new topology and coordinated control strategy of power quality conditioner based on time-sharing multiplexing integrated converter (TMIC-PQC) are proposed in this paper. By reconstructing the connection architecture of the series part, the integrated converter can operate in the parallel-connected mode under normal grid voltage conditions to achieve reactive power compensation, and operate in the series-connected mode under fluctuating grid voltage conditions to achieve voltage compensation. In addition, a coordinated control strategy and parameter design criteria for the parallel and integrated parts of the TMIC-PQC are formulated under both normal voltage and fluctuating voltage conditions, thus ensuring low power levels of each part across different modes. Compared to the traditional UPQC, the proposed topology merely requires the addition of a decoupling branch consisting of an auxiliary capacitor, thereby reducing the converter capacity by approximately 30%. The simulation and experimental results demonstrate the validity of the proposed topology and coordinated control strategy.