Motor drive device

A motor drive device that converts DC voltage of a battery into AC voltage to drive an AC motor, comprising:

• a power conversion circuit having a plurality of legs that are connected in parallel, each leg having an upper arm with a switch element and a lower arm with a switch element;
• a first switch circuit connected between AC terminals of the plurality of legs of the power conversion circuit and the AC motor;
• a second switch circuit connected between the AC terminals of the plurality of legs of the power conversion circuit and an AC power supply;
• a third switch circuit connected between the battery and DC terminals of the power conversion circuit;
• a transformer whose primary side is connected between the AC terminals of two of the legs of the power conversion circuit;
• and
• an AC/CD conversion circuit, connected to a secondary side of the transformer, between a pair of output terminals to which the battery is connected,
• wherein when the first and third switch circuits are turned off and the second switch circuit is turned on, the battery is charged by AC voltage of the AC power supply being supplied to the power conversion circuit, high frequency AC voltage being generated, and the high frequency AC voltage being converted via the transformer and AC/DC conversion circuit into a DC voltage that is supplied to the battery, and
• wherein when the first and third switch circuits are turned on and the second switch circuit is turned off, DC voltage of the battery is converted into AC voltage by the power conversion circuit and supplied to the AC motor.

A motor drive device that converts DC voltage of a battery into AC voltage to drive an AC motor, comprising:

• a power conversion circuit having a plurality of legs that are connected in parallel, each leg having an upper arm with a switch element and a lower arm with a switch element;
• a fourth switch circuit, connected between AC terminals of the plurality of legs of the power conversion circuit and the AC motor, that can short-circuit the AC terminals of the plurality of legs or connect the AC terminals to the AC motor;
• a power factor control circuit;
• a second switch circuit connected via the power factor control circuit between DC terminals and AC terminals of the power conversion circuit;
• a third switch circuit connected between the battery and DC terminals of the power conversion circuit;
• a transformer whose primary side is connected between the relevant AC terminals of those of the plurality of legs whose AC terminals are short-circuited by the fourth switch circuit and an AC terminal of another leg;
• and
• an AC/DC conversion circuit, connected to a secondary side of the transformer, between a pair of output terminals to which the battery is connected,
• wherein when the second switch circuit is turned on and the third switch circuit is turned off, and AC terminals of the plurality of legs are short-circuited by the fourth switch circuit, the battery is charged by AC voltage of the AC power supply being converted into high frequency AC voltage by the power conversion circuit via the power factor control circuit, and the high frequency AC voltage being converted via the transformer and the AC/DC conversion circuit into DC voltage that is supplied to the battery, and
• wherein when the second switch circuit is turned off and the third switch circuit is turned on, and AC terminals of the plurality of legs are connected to the AC motor by the fourth switch circuit, DC voltage of the battery is converted into AC voltage by the power conversion circuit and supplied to the AC motor.

A motor drive device that converts DC voltage of a battery into AC voltage to drive a plurality of AC motors configured as motor/generators that can also operate as AC generators, comprising:

• a plurality of power conversion circuits each having a plurality of legs with upper and lower arms connected in parallel, each leg having an upper arm with a switch element and a lower arm with a switch element;
• a fourth switch circuit, provided between AC terminals of the plurality of legs of one power conversion circuit and one motor/generator, that can short-circuit AC terminals of the plurality of legs or connect the AC terminals to one motor/generator;
• a second switch circuit connected between AC terminals of the plurality of legs of another power conversion circuit and an AC power supply;
• a first switch circuit connected between AC terminals of the plurality of legs configuring the other power conversion circuit and another motor/generator;
• a third switch circuit connected between the battery and DC terminals of the one power conversion circuit;
• a transformer whose primary side is connected between the relevant AC terminals of those of the plurality of legs whose AC terminals are short-circuited by the fourth switch circuit and an AC terminal of another leg;
• and
• an AC/DC conversion circuit, connected to a secondary side of the transformer, between a pair of output terminals to which the battery is connected,
• wherein when the first and third switch circuits are turned off and the second switch circuit turned on, and AC terminals of the plurality of legs are short-circuited by the fourth switch circuit, the battery is charged by AC voltage of the AC power supply being converted into DC voltage by the other power conversion circuit, subsequently converted into high frequency AC voltage by the one power conversion circuit, and the high frequency AC voltage being converted via the transformer and AC/DC conversion circuit into DC voltage and supplied to the battery, and
• wherein when the second switch circuit is turned off and the first and third switch circuits turned on, and AC terminals of the plurality of legs are connected to the one motor/generator by the fourth switch circuit, DC voltage of the battery is converted into AC voltage by the one power conversion circuit and the other power conversion circuit, and supplied to each motor/generator.

A motor drive device that converts DC voltage of a battery into AC voltage to drive an AC motor, comprising:

• a first power conversion circuit having a plurality of legs with upper and lower arms that are being connected in parallel, each upper arm having a switch element and each lower arm having a switch element;
• a boosting second power conversion circuit having a single leg with upper and lower arms that are connected in parallel with the first power conversion circuit, the upper leg having a switch element and the lower leg having a switch element;
• a first switch circuit connected between AC terminals of the plurality of legs of the first power conversion circuit and the AC motor;
• a second switch circuit connected between AC terminals of the plurality of legs of the first power conversion circuit and an AC power supply;
• a second power conversion circuit having a plurality of legs that are connected in parallel, each leg having an upper arm with a switch element and a lower arm with a switch element;
• a third switch circuit connected between the battery and the second power conversion circuit;
• a transformer whose primary side is connected between an upper and lower arm connection point of one leg of the first power conversion circuit and an upper and lower arm connection point of the second power conversion circuit;
• an AC/DC conversion circuit connected to a secondary side of the transformer;
• and
• a fifth switch circuit connected between an output of the AC/DC conversion circuit and the battery,
• wherein when the first and third switch circuits are turned off and the second and fifth switch circuits turned on, the battery is charged by AC voltage of the AC power supply being supplied to the first power conversion circuit, high frequency AC voltage being generated by DC/AC conversion operations by one leg of the first power conversion circuit and the second power conversion circuit, and the high frequency AC voltage being converted via the transformer and AC/DC conversion circuit into DC voltage and supplied to the battery, and
• wherein when the first and third switch circuits are turned on and the second and fifth switch circuits turned off, DC voltage of the battery is boosted by the second power conversion circuit, subsequently converted into AC voltage by the first power conversion circuit, and supplied to the AC motor.