Power supply unit and washing machine

Abstract

The load is rotated at a stable rotational speed. [Solution] The rectifier circuit 210 includes a first leg 81 in which the connection point 61 of diodes 11 and 12 is connected to the first AC input terminal 601 of the AC power supply 500, a second leg 82 including switching elements 31 and 32, and a reactor 41 connected between the connection point 62 and the second AC input terminal 602. The inverter circuit 230 includes a third leg 83 in which the connection point 66 of switching elements 33 and 34 is connected to the motor 400 via the first AC output terminal 71, and a fourth leg 84 in which the connection point 67 of switching elements 35 and 36 is connected to the motor 400 via the second AC output terminal 72. The connection point 65 of smoothing capacitors 21 and 22 is connected to the motor 400 via the third AC output terminal 73. The control circuit 300 independently controls a first switch group including switching elements 31 and 32 and a second switch group including switching elements 33 to 36.

Claims

1. A rectifier circuit connected to an AC power supply, A three-phase inverter circuit connected to a load, The rectifier circuit and the inverter circuit are connected to a first and second smoothing capacitor, Equipped with a control circuit, The rectifier circuit described above is A first leg includes first and second diodes, the connection point of the first and second diodes being connected to the first AC input terminal of the AC power supply, A second leg including first and second switching elements, The system includes a reactor connected between the connection point of the first and second switching elements and the second AC input terminal of the AC power supply, The aforementioned inverter circuit is A third leg includes third and fourth switching elements, the connection point of the third and fourth switching elements being connected to the load via a first AC output terminal, A fourth leg comprising a fifth and a sixth switching element, wherein the connection point of the fifth and sixth switching elements is connected to the load via a second AC output terminal, The connection point of the first and second capacitors is connected to the load via the third AC output terminal. The control circuit independently controls the first switch group including the first and second switching elements and the second switch group including the third to sixth switching elements. power supply.

2. The system further includes a detection unit that detects the zero-crossing point of the AC input voltage from the aforementioned AC power supply, The aforementioned control circuit is Includes a first control unit that controls the first group of switches in synchronization with the zero-crossing point detected by the detection unit, The power supply device according to claim 1.

3. The control circuit includes a second control unit that generates a PWM signal so that the rotational speed of the load reaches a target value and controls the second switch group, The second control unit is, Based on the speed command value indicating the target value, a three-phase voltage command value is generated. By subtracting the voltage command value of one of the three phases from each of the remaining two phases' voltage command values, a two-phase differential voltage command value is generated. Based on the two-phase differential voltage command values, the PWM signals of the third to sixth switching elements are generated. The power supply device according to claim 1 or 2.

4. The rectifier circuit includes a third and a fourth diode, and a fifth leg in which the connection point of the third and fourth diodes is connected to the connection point of the first and second capacitors. A first switching element that switches between a first connection state in which one end of the reactor is connected to the connection point of the first and second switching elements, and a second connection state in which one end of the reactor is connected to the connection point of the first and second capacitors, The present invention further includes a second switching element that switches between a third connection state in which the third AC output terminal is connected to the connection point of the first and second capacitors, and a fourth connection state in which the third AC output terminal is connected to the connection point of the first and second switching elements. The power supply device according to claim 1 or 2.

5. When the first switching element switches to the first connection state, the second switching element switches to the third connection state. When the first switching element switches to the second connection state, the second switching element switches to the fourth connection state. The power supply device according to claim 4.

6. The first switching element and the second switching element are composed of a single component. The power supply device according to claim 4.

7. The aforementioned control circuit is When the load is in the first load state, the first switching element is set to the first connection state and the second switching element is set to the second connection state. When the load is lower than the first load state, the first switching element is set to the second connection state, and the second switching element is set to the fourth connection state. The power supply device according to claim 4.

8. The rectifier circuit includes a fifth leg which includes the third and fourth diodes, The first to fourth diodes are composed of a 4-in-1 diode module. The first to sixth switching elements are configured in a 6-in-1 inverter module. The power supply device according to claim 1 or 2.

9. A washing machine comprising the power supply device according to claim 1 or 2.

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