摘要 |
Control mode switching determination is made as a part of a main loop (control period (Tm)) for overall control of an AC electric motor. Control period (Tc) of a rectangular wave voltage control mode is shorter than the execution period (Tm) of the control mode switching determination. When switching from the rectangular wave voltage control mode to PWM control mode is determined, change in voltage phase of the rectangular wave voltage is inhibited from the timing (time t0) of control mode switching determination until the next execution of the main loop, that is, until the timing (time t1) at which the control mode is actually switched, to maintain voltage phase of the rectangular wave voltage at the time of control mode switching determination. Consequently, in a drive controller for an AC electric motor allowing switching between control modes, control mode can appropriately be switched without making unstable the operation of the AC electric motor.
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