| 摘要 |
PCT No. PCT/JP91/01161 Sec. 371 Date May 7, 1992 Sec. 102(e) Date May 7, 1992 PCT Filed Aug. 30, 1991 PCT Pub. No. WO92/04763 PCT Pub. Date Mar. 19, 1992.A driving system for an induction motor which is capable of properly controlling the speed of an induction motor over its high-speed revolution range and also features an excellent responsiveness to a speed command. In this system, a slip pulse (SSP) and a phase shifting pulse (FSP) are calculated by a slip pulse generator circuit (20) and a phase shifting pulse generator circuit (21) in accordance with slip pulse data (SB) and phase shifting pulse data (FB) which are calculated by a processor (1) in accordance with the speed command and an output of a speed detector. A counter (24) issues the first changeover signal (CS1) each time it receives a specified number of pulses from a pulse overlapping circuit (23). The first changeover signal corresponds to a feedback pulse calculated in accordance with the output of the speed detector and also to the slip pulse and the phase shifting pulse added. A square wave output circuit (26) generates square wave signals (Us through &upbar& Ws) in accordance with the first changeover signal, the second changeover signal (CS2), which is obtained by delaying the first changeover signal, and rotational direction identifying signals (RS, &upbar& RS) received from the pulse overlapping circuit. While the motor is running at high speed, the drive of the motor is controlled in accordance with the square wave signals; while it is running at low speed, PWM signals (Up through &upbar& Wp) generated by the processor are used in place of the square wave signals.
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