Rotary electric machine driving device

A rotary electric machine driving device that drives and controls an alternating-current rotary electric machine, the rotary electric machine driving device comprising:

• an inverter that is electrically interposed between a direct-current power supply and the rotary electric machine, and converts electric power between a direct current and an alternating current;
• a smoothing capacitor that is electrically interposed between the direct-current power supply and the inverter, and is connected between a positive pole and a negative pole on a direct-current side of the inverter;
• and
• an inverter control unit that controls switching of a switching element of the inverter according to a predefined switching frequency, wherein
• a value of a direct-current side current gain obtained by dividing a current of the direct-current power supply by a system current that is a current on the direct-current side of the inverter includes a frequency characteristic in which the value of the direct-current side current gain increases as the frequency increases from zero, reaches a maximum value at a resonance point at which the frequency becomes a resonance frequency, and decreases as the frequency increases from the resonance point serving as an inflection point, and
• the inverter control unit sets the switching frequency to a frequency that is equal to or higher than the resonance frequency and that is equal to or higher than a frequency at which the value of the direct-current side current gain is equal to a value thereof at a frequency of zero in the frequency characteristic.

A rotary electric machine driving device that controls drive of an alternating-current rotary electric machine, the rotary electric machine driving device comprising:

• an inverter that is electrically interposed between a direct-current power supply and the rotary electric machine, and converts electric power between a direct current and an alternating current;
• a smoothing capacitor that is electrically interposed between the direct-current power supply and the inverter, and is connected between a positive pole and a negative pole on a direct-current side of the inverter;
• and
• an inverter control unit that controls switching of a switching element of the inverter according to a predefined switching frequency, wherein
• a value of a direct-current side voltage gain obtained by dividing a system voltage that is a voltage on the direct-current side of the inverter by a system current that is a current on the direct-current side of the inverter includes a frequency characteristic in which the value of the direct-current side voltage gain increases as the frequency increases from zero, reaches a maximum value at a resonance point at which the frequency becomes a resonance frequency, and decreases as the frequency increases from the resonance point serving as an inflection point,
• a value of a direct-current side current gain obtained by dividing a current of the direct-current power supply by the system current that is the current, on the direct-current side of the inverter includes a frequency characteristic in which the value of the direct-current side current gain increases as the frequency increases from zero, reaches a maximum value at a resonance point at which the frequency becomes a resonance frequency, and decreases as the frequency increases from the resonance point serving as an inflection point
• the inverter control unit sets the switching frequency to a frequency that is equal to or higher than the resonance frequency and that is equal to or higher than a frequency at which the value of the direct-current side voltage gain is equal to a value thereof at a frequency of zero in the frequency characteristic, and
• the inverter control unit sets the switching frequency to a frequency that is equal to or higher than the resonance frequency and that is equal to or higher than a frequency at which the value of the direct-current side current gain is equal to a value thereof at a frequency of zero in the frequency characteristic.