PURPOSE: To induce exact line-to-line voltage, by inducing the line voltage between an inverter and a motor, with DC voltage for input to the inverter, and switching signal controlling the inverter.
CONSTITUTION: DC voltage for input to an inverter 4 is detected by an insulating amplifier 6. The input of DC voltage signal for output generated from the insulating amplifier 6, to the respective analog switches 8, 9 is provided and in the meantime, the input of the signal to an operational amplifier 7 is provided and is inverted, and after that, the input of the inverted voltage signal to the respective analog switches 8, 9 is provided. Besides, the input of the switching signal of a control circuit 5, to the analog switches 8, 9 is provided. Then, by the respective analog switches 8, 9, according to the switching action of the inverter 4, any of the DC voltage, the inverted voltage, and zero voltage is selected, and by the selection, line-to-line voltage Vab and Vac based on (a) phase are induced.
KIMURA FUMITAKA
OYAMA KAZUNOBU
| JPS61185089A | 1986-08-18 |