| 摘要 |
PURPOSE:To largely reduce a current ripple generated in a motor current by switching a current circulating mode by a coincidence signal when the positive and the negative of voltage and current detection signals are equal. CONSTITUTION:A voltage detection signal Vs(u) and a current detection signal is(u) are respectively input to comparators 852, 853 to discriminate positive or negative, input to exclusive OR circuit 854, which outputs a coincidence signal G when the positive and the negative are equal. The period that the coincidence signals G, H, J of phases are simultaneously output is detected by an AND circuit 855, a fire signals are output from firing circuits 85a, 85b, 85c by an output signal M to form a circulating mode with switching element for forming a PWM inverter. Six switching elements for forming a PWM inverter are turned OFF at the prescribed timing during the period that the coincidence signals of the phases are not output to form a circulating mode by diodes. |
