Study of the methods building the voltage of DC side with enable logical for UPQC

Unified power quality conditioner (UPQC) is a kind of comprehensive power quality compensation equipment with complex circuit and structure. Starting UPQC involved in the establishment of the dc side capacitance voltage, logical sequence of series, parallel compensator and load, namely each part of UPQC must have certain of start time sequence and logic control strategy. This paper discusses three establishing method of the capacitor voltages, which known as can be considered as dc power, on dc side of UPQC, their advantages and disadvantages were analyzed, too. Then he control logic of UPQC starting, namely the order of power supply, or series and parallel compensator, load, was discussed based on the different capacitor voltage established method. The reason of adopting these switching sequences was analyzed and the detailed start logic diagram was drawn. Finally, different switching sequences were simulating by MATLAB/Simulink. The simulation results show that the proposed strategy is effective.