| 摘要 |
PURPOSE:To effect a stable control as well as reduce torque ripple in low-frequency regions and improve the control efficiency in high-frequency regions, by effecting PAM and PWM controls in a composite manner. CONSTITUTION:A pulse-amplitude modulation circuit is composed of a voltage transformation reference circuit 6, a voltage detector 7, a differential amplifier 8, a triangle generator 10, a comparator 9 and a chopper driving circuit 11. On the other hand, a pulse-width modulation circuit is composed of a voltage reference circuit 12, the triangle wave generator 10, a comparator 14, a V/F converter 13, a waveform synthesizer 15 and a driver circuit 10'. In low-frequency regions a PWM control is effected, while in high-frequency regions a PAM control is performed, to obtain an output voltage of an inverter 2. |
