Independent DC capacitance parallel multiple module SVG based on CPS-SPWM
To fit for the demand of extending the power, increasing maintainability and improving performance, a SVG with parallel independent DC capacitance converter modules is presented. In respect that the parameter difference among converters, reactive power of total output sharing has to be resolved. By analyzing the parallel converter mathematics model with DQ analytic transformation, a new control strategy is proposed, which is based on double close-loop decoupling control, reactive power balance current sharing. To reduce tracking error of current, source voltage in d-q coordinators feed forward method is adopted. Active and reactive current, and DC voltage controller is designed. Further, for the purpose of reducing switch frequency of single module, CPS-SPWM is employed to operate the equipment. A based on double FPGA-DSP controller is devised, and a 2Mvar platform is carried out. The simulation and practical performance of SVG are given. The validity and feasibility of the method is demonstrated by the results and the industrial application.