Patent ID: 9621103
Date: 2017-04-11
CPC Classifications: H02M,H02P,Y02B

Claim:
1. A circulating current and oscillating current suppressing method for a plurality of inverter drivers of a parallel inverter driver system, wherein each inverter driver comprises an entity inductance device configured to suppress a transition three-phase current outputted from a switch device in the inverter driver, the method comprising the following steps: (a) collecting a suppressing three-phase current of the output of each inverter driver and a summation current information which generated after summing all the suppressing three-phase currents of the inverter drivers by using a voltage generation unit of a virtual inductance device, and calculating the collected current information by using an impedance to generate a corrected three-phase voltage in each inverter driver correspondingly; (b) comparing the corrected three-phase voltage of each inverter driver with a three-phase voltage command of each inverter driver by using a voltage comparator unit of the virtual inductance device to generate a compensated three-phase voltage; (c) converting the compensated three-phase voltage of each inverter driver to a compensated three-phase current by using a voltage/current calculation unit of the virtual inductance device, wherein the compensated three-phase current is corresponding to a current generated by simulating the transition three-phase current which is co-suppressed by a virtual inductance unit and the entity inductance device; (d) collecting the transition three-phase current of each inverter driver and the compensated three-phase current of each inverter driver, and generating an index in each inverter driver according to the collected results and a desired circulating current quantity and/or a desired zero-sequence current quantity of the parallel inverter driver system; (e) generating a zero-sequence voltage in each inverter driver associated with the circulating current and/or the zero-sequence current of the parallel inverter driver system according to the index, the three-phase voltage command and an operating mode; (f) correcting the three-phase voltage command by the zero-sequence voltage; and (g) generating a duty cycle signal according to the corrected three-phase voltage command for controlling switch operations of the corresponding inverter driver.