Patent ID: 9692346
Date: 2017-06-27
CPC Classifications: H02P

Claim:
1. An inverter control apparatus for application to a system comprising a 3-phase inverter having a plurality of switching devices corresponding to respective phases of the 3-phase inverter and a 3-phase rotary machine having respective phase windings electrically connected to the inverter control apparatus, the inverter control apparatus comprising a plurality of switching devices and operating signal generating circuitry which generates PWM (pulse width modulation) operating signals to control the switching devices for producing flows of AC current in the rotary machine; wherein in each of successive processing periods, the operating signal generating circuitry generates the PWM operating signals such as to satisfy a first condition and a second condition, the first condition being that a state of a switching device corresponding to a highest phase of the 3-phase inverter is held fixed throughout the processing period, where the highest phase has a phase voltage that is highest among respective phase voltages of the three phases during the processing period, the second condition being that a switching device corresponding to a lowest phase of the 3-phase inverter undergoes a greater number of switching operations during the processing period than a switching device corresponding to an intermediate phase of the 3-phase inverter, where the lowest phase has a phase voltage that is lowest among the respective phase voltages of the three phases during the processing period, and the intermediate phase has a phase voltage that is intermediate between the respective phase voltages of the highest phase and the lowest phase during the processing period.