| 摘要 |
PURPOSE:To improve the efficiency of using a ROM, by storing conduction data and their continuous time in the ROM. CONSTITUTION:A PWM type inverter 4 is provided with a registter 9 for driving the inverter, a waveform shaping circuit 10, and a base drive circuit 11, and according to the storage contents of a ROM 12, said inverter 4 is controlled via said register 9 and the like. So far as the ROM 12 is concerned, into addresses, the momentary output voltage data 13 of three-phase alternating- current and the continuous time data 14 are written. The bit number of said data 14 is determined by the minimum pulse width of a PWM controlling waveform, and actual pulse widths are set by the continuous time data 14 at the respective addresses. As a result, the output of said voltage data 13 of the ROM 12 is directed to the register 9, and the output of the time data 14 is directed to an electrical angle counter 18. Then, the high-order bit of an address counter 2 can be always used as final address signal.
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