CONTROLLING SYSTEM FOR INVERTER OPERATING WITH PHASE DIFFERENCE

摘要

PURPOSE:To reduce the component of chopping frequency by a system wherein the phase difference between inverters for performing the phase difference operation with n-phase is made to be 360 deg./n.(1+ or -1/6m) with a shift of 1/n in a chopping period, assuming that pulse mode during one cycle is (m). CONSTITUTION:An output 102 from the final stage of a frequency divider 2 is input to a three-phase generator 5a which outputs a three-phase signal 105a. A synchronous signal 103 is input to a triangular wave generator 4 which outputs a triangular wave signal 104. A PWM modulator 8a outputs a chopping signal 108a corresponding to a comparison between the triangular wave signal 104 and an inverter output voltage instruction Vref1 in their levels. The synchronous signal 103 and the output signal 102 are input to a delay circuit 10 which outputs a signal 110. By so doing, a three-phase generator 5b outputs a three-phase signal 105b delayed in time corresponding to a half-period of the synchronous signal 103 with respect to the triangilar signal 105a.