Patent attributes
In a control apparatus for an AC motor, a voltage waveform specifying unit of an inverter control unit specifies a voltage waveform for operating the inverter, based on a voltage vector calculated by a voltage command calculation unit. A spectrum amplitude extraction unit acquires values of bus current of the inverter and extracts the spectrum amplitude of the specific frequency that corresponds to the LC resonance frequency of the converter. A boost/non-boost state judgement unit of a converter control unit determines whether the state required by the converter in the next control cycle is the boost state or the non-boost state. When the spectrum amplitude of the specific frequency, correlated with the voltage waveform, is higher than the judgement threshold value and the converter is in the non-boost state, a voltage command value alteration unit changes the voltage command reference value such that the converter transitions to the boost state.
