| 摘要 |
PURPOSE:To eliminate the distortion of voltage waveform by suppressing fluctuation in the output voltage from an inverter. CONSTITUTION:In the control circuit for a voltage type PWM control inverter subjected to two arm modulation control and set with an ON delay time, a compensation amount operating unit 3 operates voltage compensation amounts edu, edv, edw for compensating the errors of inverter output voltage caused by the ON delay time. The voltage compensation amounts are added to the output voltage command values eu*, ev*, ew* for respective phases to produce new voltage command values which are fed to an inverter 20. The compensation amount operating unit 3 comprises means for superposes the forward voltage drop of a semiconductor switching element determined by the polarities of output current and output voltage command value for some phase on the voltage compensation amount of other phase if all semiconductor switching elements on the upper and lower arms of that phase are in the ON or OFF section thus clearing the voltage compensation amount for that phase. |
