DEAD-TIME COMPENSATION APPARATUS OF PWM INVERTER AND METHOD THEREOF

摘要

A dead-time compensation method is applied to a PWM inverter, which is provided to drive an induction motor using a constant V/f control. The method first calculates a root-mean-square current of the output instantaneous current of the inverter. Afterward, a lookup table of the root-mean-square current is used to obtain a dead-time compensation base voltage and a dead-time compensation per-unit voltage. Finally, the dead-time compensation base voltage is multiplied by the dead-time compensation per-unit voltage to produce a dead-time compensation voltage of the PWM inverter. Accordingly, the method reduces complexity of converting the current to the voltage to reach a faster real-time response. Furthermore, a more accurate dead-time compensation voltage is obtained without increasing hardware costs and the efficiency of operating the induction motor is improved at low speed and light load condition.