1996 Volume 116 Issue 9 Pages 924-933
The carrier frequency tends to be raised in the PWM inverter due to the appearance of high-speed switching devices. The PWM inverter which is operated by the high carrier frequency is easily influenced by the switching dead-time in comparison with the square-wave inverter. In case that the load is a motor, it is known that the switching dead-time causes serious problems such as current waveform distortion, increased torque ripples at low speed and light load operation.
In this paper, the permanent-magnet AC servo motor driven by the PWM inverter was analyzed in consideration of the output voltage deviation and the zero-current-clamping phenomenon during the switching dead-time. The effect of the output voltage deviation on the current waveform were clarified by the analytic results. The current behavior and the switching states around the zero-current clamps were clarified, too. Furthermore, the compensation for the output voltage deviation was proposed and the effect of the compensation was confirmed by the analytic and experimental results. The analytic waveforms coincided with experimental waveforms and the validity of the analysis was given by the coincidence.