Matsushita Electric Industrial Co., Ltd.

Masahiro Kadono

Takashi Deguchi

Shinji Naka

Kazumi Kouyama

Shigeki Harada

In an inverter-drive controlling apparatus in accordance with a simulated sinusoidal wave non-uniform PWM system, data of one carrier period comprises data region of integer number, and at least one HALT region, and the carrier period T.sub.0 and data unit timer T.sub.2 are produced by frequency division from a common reference oscillator, and the frequency divisions to obtain the carrier period T.sub.0 and the data unit timer T.sub.2 are controlled individually from each other, thereby output frequency to the inverter and output voltage thereto can be desirably controlled in digital process; thereby even utilizing limited area for storing sinusoidal wave data, accurately simulated sinusoidal waveform and good characteristic of the voltage-frequency is attainable and completely synchronized switching of plural waveform data regions are obtainable, thereby enabling adjusting of the revolution speed of electric motor in extremely wide range and up to a very high speed, and the waveform becomes very good.

Inverter-drive controlling apparatus

In a controlling apparatus for a simulated sinusoidal wave of unequal width PWM inverter, wherein PWM signal comprises a data region and a HALT region in each of carrier period timer, the carrier period timer T.sub.0 and data unit timer T.sub.2 are controlled by each other independent digital values by each other independent microcomputers (5, 6) or by use of each other different timers (10, 11), and the data unit timer T.sub.2 is controlled by an output of a power source voltage fluctuation detector (18), thereby to provide a constant voltage-frequency characteristic even at voltage fluctuation.

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Kusatsu, Japan

Masahiro Kadono