Three-phase Parabolic PWM Current Control Decoupling Method(Method II)

Compared with the traditional hysteresis control,the parabolic pulse width modulation(PWM) current control technique features a reasonably fast response,outstanding performance of average current tracking as well as an almost constant switching frequency,and could be widely used in a variety of voltage source converters(VSC).However,only the single-phase parabolic PWM current control(PCC) scheme was presented in the published literatures,and how to be used in the three-phase three-wire VSCs was not involved.In this paper,a three-phase PCC decoupling scheme was proposed by converting the three-phase three-wire system into a virtual three-phase four-wire system and a virtual zero-sequence system based on the superposition principle.With this scheme,three independent parabolic current controllers were used to control the virtual three-phase currents,and indirectly control the actual currents of the three-phase three-wire VSC with high-performance.Both simulation and experimental results verify validity and correctness of the proposed three-phase PCC decoupling scheme.