An efficient reactive power regulation based DPC method for AC/DC converters

To eliminate the cyclical fluctuation problems of the reactive power existing in the traditional direct power control (DPC), a novel method is proposed for the three-phase voltage source AC/DC converter. It employs two switching tables to select the proper switching states according to the instantaneous reactive power deviations. The design principle of the switching tables is provided to ensure the efficient reactive power regulation. Moreover, it should guarantee the steady characteristic of the converter system. The simulation model established under the MATLAB/Simulink environment and the experiment were presented to compare the characteristics obtained by the proposed strategy with that obtained by the traditional DPC strategy. The results show that the ac current obtained by the proposed strategy has the much lower total harmonic distortion rate (THD), and the fluctuation range of the reactive power has the more than two times reduction.