JPWO2021038868A5 - - Google Patents

Claims (13)

With the reactor,
A converter that has four unidirectional elements that are bridge-connected, is connected to an AC power supply via the reactor, converts the power supply voltage, which is the AC voltage output from the AC power supply, into a DC voltage, and applies it to the load. ,
A smoothing capacitor connected between the output terminals of the converter,
A first physical quantity detecting unit that detects a first physical quantity representing an operating state on the output side of the converter, and a physical quantity detecting unit.
A second physical quantity detection unit that detects a second physical quantity that represents the operating state of the input side of the converter, and
A control unit to which the first and second physical quantities are input and controls the operation of the converter,
Equipped with
Two of the four unidirectional elements in the converter are connected in series to form a first leg, and the remaining two unidirectional elements are connected in series. Make up the second leg,
At least two unidirectional elements in the first and second legs connected to the positive side of the smoothing capacitor, or two in the first and second legs connected to the negative side of the smoothing capacitor. A switching element is connected in parallel to each of the one-way element, the two one-way elements in the first leg, or the two one-way elements in the second leg.
The control unit flows through the channel of the corresponding switching element at the timing of passing through the unidirectional element and the rectifying mode in which the converter is operated in different operation modes. It has a synchronous rectification mode to make it
Through the reactor, the first switching mode in which the power supply voltage is short-circuited via the reactor at least once in a half cycle of the power supply voltage, which is the voltage of the AC power supply, and the entire range of one cycle of the power supply voltage. The operation mode has at least one of the second switching modes for short-circuiting the power supply voltage a plurality of times.
The control unit further selects the operation mode based on the ambient temperature of the switching element, the outside air temperature of the converter, and the load conditions when driving the load .
DC power supply. A drive circuit for driving the converter based on a control signal output from the control unit is provided.
The drive circuit includes a bootstrap circuit that is a power supply circuit for driving the switching element connected to the positive side of the smoothing capacitor.
As the operation mode, the second switching mode is provided.
The DC power supply device according to claim 1 , wherein in the second switching mode, the switching element connected to the bootstrap circuit does not operate ON. A drive circuit for driving the converter based on a control signal output from the control unit is provided.
The drive circuit includes a bootstrap circuit that is a power supply circuit for driving the switching element connected to the positive side of the smoothing capacitor.
As the operation mode, the first switching mode is provided.
The DC power supply device according to claim 1 or 2 , wherein the operation of the switching element connected to the bootstrap circuit is stopped based on the load condition when operating in the first switching mode. The DC power supply device according to any one of claims 1 to 3, wherein the switching element is a metal oxide semiconductor field effect transistor formed of a wide bandgap semiconductor. The DC power supply device according to claim 4 , wherein the wide bandgap semiconductor is silicon carbide, gallium nitride, gallium oxide, or diamond. The DC power supply device according to any one of claims 1 to 3, wherein the switching element is a metal oxide semiconductor field effect transistor having a superjunction structure. The DC power supply device according to any one of claims 1 to 6 , wherein the unidirectional element is a parasitic diode of a metal oxide semiconductor field effect transistor. The DC power supply device according to any one of claims 1 to 7 , wherein the unidirectional element is a diode. The DC power supply device according to any one of claims 1 to 8 .
An inverter that converts the output voltage of the DC power supply device into an AC voltage and applies it to the motor provided in the load.
A motor drive device equipped with. A blower comprising the motor driving device according to claim 9 . A compressor comprising the motor driving device according to claim 9 . An air conditioner comprising at least one of the blower according to claim 10 and the compressor according to claim 11 . The air conditioner according to claim 12 , wherein the load condition is at least one of when the air conditioner is started, when the air conditioner is abnormal, and when the air conditioner is cooled or heated.