| 摘要 |
PURPOSE:To inhibit overcurrents instantaneously by conducting PWM arithmetic operation by means of a processor by using hardware provided outside the processor. CONSTITUTION:Currents are controlled by a pulse width modulation (PWM) inverter, and an AC machine 2 as load is driven. The currents of the AC machine 2 are transmitted over a signal processor 5 through a detector 3 and an A/D converter 5, and the inverter 1 is controlled by the signal processor 5. PWM arithmetic operation being performed in the processor 5 is conducted by a PWM arithmetic circuit 6 set up outside the processor, and a limiting current detector 7 is connected so that current limitation operation is performed by the arithmetic circuit 6. Consequently, a voltage command value as an output from a current regulation arithmetic section 52 is introduced to said arithmetic circuit 6, and a PWM waveform output from the inverter 1 is formed in consideration of a detecting output from the limiting current detector 7 in the arithmetic circuit 6. Accordingly, overcurrents can be inhibited instantaneously.
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