| 摘要 |
PURPOSE:To prevent the causing of breakdown due to the uncontrolled operation of an AC rotary machine by latching a signal transmitted over a pulse width modulation signal generating circuit from a signal forming circuit by a differential signal outputted from the signal circuit. CONSTITUTION:A differentiating circuit 12 receives pulse trains corresponding to two phase sections outputted from a two-phase pulse generator 3, differentiates these pulse trains at the rise times of these pulse trains and outputs differential pulse signals. A latch circuit 13 reads pulse trains UP, VP, WP, UN, VN, WN outputted from a logic circuit 8 while latching pulse train data read until the next differential pulse signal is transmitted from the differentiating circuit 12 at a time when the differential pulse signal is transmitted. Accordingly, even when outputs from the two-phase pulse generator 3 are not acquired for some outputs from the two-phase pulse generator 3 are not acquired for some reason, a synchronous motor 1 is not operated uncontrolledly for the reason. |
