DC power-supply device and refrigeration cycle device
First Claim
1. A DC power-supply device that converts an alternating current from a three-phase AC power supply into a direct current and supplies the converted current to a load, the DC power-supply device comprising:
- a rectifier circuit that has a reactor connected to an input side or an output side thereof and that rectifies the alternating current from the three-phase AC power supply;
a first capacitor and a second capacitor that are connected in series between output terminals to the load;
a charging unit that selectively charges one or both of the first capacitor and the second capacitor; and
a control unit that controls the charging unit, wherein;
the charging unit includes;
a first switching element and a second switching element that are connected in series and are switched at a frequency that is a multiple n (where n is a natural number) of a frequency of the three-phase AC power supply,a first backflow prevention element that prevents backflow of a stored electric charge of the first capacitor to the first switching element, anda second backflow prevention element that prevents backflow of a stored electric charge of the second capacitor to the second switching element,a point between the first switching element and the second switching element and a point between the first capacitor and the second capacitor are connected to each other,the DC power-supply device further comprises a power-supply voltage detection unit,the control unit controls an operation mode,the operation mode includes;
a full-wave rectification mode in which the first switching element and the second switching element are always turned off and on-duty ratios of the first switching element and the second switching element are 0%, anda boosting mode in which the first switching element and the second switching element are alternately turned on at a charging frequency, andin the boosting mode, an output voltage is controlled by gradually increasing the on-duty ratios of the first switching element and the second switching element.
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Accused Products
Abstract
A DC power-supply device that suppresses an excessive inrush current, can prevent breakage of elements and burnout of circuits, and converts alternating current from a three-phase AC power supply into direct current to supply it to a load, includes a rectifier circuit having a reactor connected to input or output side thereof and rectifying the alternating current from the three-phase AC power supply; first and second capacitors and connected in series between output terminals to the load; a charging unit selectively charges one or both of the first and second capacitors; and a control unit controlling the charging unit. When charging of the first and second capacitors is started, the control unit reduces the on-duty ratio, and then, until the on-duty ratio during a normal operation is reached, the control unit executes control such that the on-duty ratio is gradually increased as a predetermined time period is passed.
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Citations
13 Claims
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1. A DC power-supply device that converts an alternating current from a three-phase AC power supply into a direct current and supplies the converted current to a load, the DC power-supply device comprising:
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a rectifier circuit that has a reactor connected to an input side or an output side thereof and that rectifies the alternating current from the three-phase AC power supply; a first capacitor and a second capacitor that are connected in series between output terminals to the load; a charging unit that selectively charges one or both of the first capacitor and the second capacitor; and a control unit that controls the charging unit, wherein; the charging unit includes; a first switching element and a second switching element that are connected in series and are switched at a frequency that is a multiple n (where n is a natural number) of a frequency of the three-phase AC power supply, a first backflow prevention element that prevents backflow of a stored electric charge of the first capacitor to the first switching element, and a second backflow prevention element that prevents backflow of a stored electric charge of the second capacitor to the second switching element, a point between the first switching element and the second switching element and a point between the first capacitor and the second capacitor are connected to each other, the DC power-supply device further comprises a power-supply voltage detection unit, the control unit controls an operation mode, the operation mode includes; a full-wave rectification mode in which the first switching element and the second switching element are always turned off and on-duty ratios of the first switching element and the second switching element are 0%, and a boosting mode in which the first switching element and the second switching element are alternately turned on at a charging frequency, and in the boosting mode, an output voltage is controlled by gradually increasing the on-duty ratios of the first switching element and the second switching element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification