Research on hysteresis tracking control method with constant switching frequency for UPQC based on voltage space vector

For Unified Power Quality Conditioner (UPQC) adopting traditional hysteresis control method, unstable switching frequency causes great switching loss, and voltage space vector control method leads to a serious interphase interference to three-phase three-wire systems. To solve these problems, a hysteresis tracking control method with constant switching frequency based on voltage space vector is proposed. The hysteresis control method with constant switching frequency changes hysteresis band according to the DC capacitor voltage, supply voltage and differentiation of reference current wave to realize the fixed switching frequency. On this basis, the voltage space vector control method is introduced to change the problem of compensation control into that of how to select the right output voltage vector. So the switching loss is reduced and the problem of interphase interference is solved. At last, the control method proposed in this paper is verified possible and effective by the results of simulation of MATLAB and experiment.