| 摘要 |
PURPOSE:To make it possible to suppress an adverse effect caused by a dead time, by computing a compensation amount on the basis of the amplitude and direction of an output current of an invertor and the amplitude of a stray capacitance of a switching element. CONSTITUTION:The operation of a controller for a phase U is explained in the following. A current detector 5 for the phase U detects the amplitude and direction of an output current 1 for the phase U and inputs them to a compensation amount computing part 1b. A sine wave voltage instruction generating part 1a generates a sine wave voltage instruction signal on the basis of a frequency instruction signal and an amplitude instruction signal and outputs it to an addition part 1c. The compensation amount computing part 1b computes a compensation amount in view of a stray capacity C and outputs it to the addition part 1c. A comparing part 1f compares the data from the addition part 1c with a triangular wave carrier signal from a triangular wave generating part 1e and generates a PWM signal. A delay generating part 1h inserts a dead time period (DT) into the PWM signal and drives a switching transistor(Tr) Q1. Besides, it inserts the DT into an inverted PWM signal from an inverting part 1g and drives TrO2. |
