| 摘要 |
A rectangular wave or a waveform similar to the rectangular wave is output with an conductive angle no less than 120° but no more than 150° during low-speed operation, but output a rectangular wave, a sine wave or a waveform similar to them with an conductive angle no less than 130° but under 180° by changing the frequency only while maintaining the PWM duty constant at high-speed operation, making it possible to realize high-efficiency and low-noise operation at low-speed operation, secure stable high speed, and prevent peak current of effective current because the current waveform also comes closer to sine wave. |
