Power supply device

A power supply device applied to a vehicle in which a generator motor is mounted as a drive source for generating drive power of the vehicle,

• the power supply device comprising:
• a battery that can be charged and discharged;
• an inverter having a plurality of legs, each of which includes an upper arm having a third switching element and a lower arm connected to the upper arm in series and having a fourth switching element, the inverter performs a DC-AC converting operation that converts a secondary-side voltage to an AC voltage and applying the AC voltage to the generator motor when a state of each of the third switching element and the fourth switching element is repeatedly switched between an ON state and an OFF state;
• a converter including an upper arm having a first switching element and a lower arm connected to the upper arm in series and having a second switching element, the converter performs a voltage converting operation that increases a primary-side voltage to be applied to the converter from the battery and applying an increased voltage as the secondary-side voltage to the inverter when a state of the second switching element is repeatedly switched between an ON state and an OFF state;
• an overvoltage determination circuit that determines whether the primary-side voltage is at least equal to a specified threshold;
• and
• an electronic control unit configured to cause the converter to perform the voltage converting operation and cause the inverter to perform the DC-AC converting operation, the electronic control unit configured to maintain the states of all of the first switching element, the second switching element, the third switching element, and the fourth switching element to be the OFF state when the overvoltage determination circuit determines that the primary-side voltage becomes at least equal to the specified threshold, and the electronic control unit configured to perform i) and ii) when the overvoltage determination circuit determines that a state where the primary-side voltage is at least equal to the specified threshold continues for a specified time or longer,
• i) increase the primary-side voltage by repeatedly switching the state of the second switching element between the ON state and the OFF state while maintaining the state of the first switching element to be the OFF state, and apply the increased voltage as the secondary-side voltage to the inverter, and
• ii) convert the secondary-side voltage to the AC voltage by repeatedly switching each of the states of the third switching element and the fourth switching element between the ON state and the OFF state, and apply the AC voltage to the generator motor.