AC-DC converter and compressor driving apparatus and air conditioning apparatus using the same
First Claim
1. An AC-DC converter comprising:
- a rectifier connected to an AC power supply via a reactor;
a plurality of capacitors connected in series across output terminals of the rectifier;
a first bidirectional switch having one end connected to one input terminal of the rectifier and another end connected to a connecting point between a plurality of capacitors;
a second bidirectional switch having one end connected to the other input terminal of the rectifier and another end connected to the other end of the first bidirectional switch;
a normally closed third bidirectional switch inserted between the connecting point of the other end between the first and second bidirectional switches and a connecting point between the plurality of capacitors; and
control means for actuating the first and second bidirectional switches during a half cycle of the AC power supply so as to control a voltage input to the rectifier to obtain a desired value of an output voltage.
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Accused Products
Abstract
An AC-DC converter is provided which suppresses a harmonic current and improves power factor at low cost. Such an AC-DC converter includes a rectifier connected to an AC power supply via a reactor, capacitors connected in series across the output terminals of the rectifier, a first bidirectional switch having one end connected to one input terminal of the rectifier and the other end connected to a connecting point of capacitors, a second bidirectional switch having one end connected to the other input terminal of the rectifier and the other end connected to the other end of the first bidirectional switch, and a control circuit for actuating the first and second bidirectional switches during a half cycle of the AC power supply so as to control a voltage inputted to the rectifier to a desired output voltage.
34 Citations
28 Claims
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1. An AC-DC converter comprising:
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a rectifier connected to an AC power supply via a reactor; a plurality of capacitors connected in series across output terminals of the rectifier; a first bidirectional switch having one end connected to one input terminal of the rectifier and another end connected to a connecting point between a plurality of capacitors; a second bidirectional switch having one end connected to the other input terminal of the rectifier and another end connected to the other end of the first bidirectional switch; a normally closed third bidirectional switch inserted between the connecting point of the other end between the first and second bidirectional switches and a connecting point between the plurality of capacitors; and control means for actuating the first and second bidirectional switches during a half cycle of the AC power supply so as to control a voltage input to the rectifier to obtain a desired value of an output voltage. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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7. An AC-DC converter, comprising
a rectifier connected to an AC power supply via reactor; -
a plurality of capacitors connected in series across output terminals of the rectifier; a first bidirectional switch having one end connected to one input terminal of the rectifier and another end connected to a connecting point between a plurality of capacitors; a second bidirectional switch having one end connected to the other input terminal of the rectifier and another end connected to the other end of the first bidirectional switch; and control means for actuating the first and second bidirectional switches during a half cycle of the AC power supply so as to control a voltage input to the rectifier to obtain a desired value of an output voltage, wherein the control means reallocates the actuation signal subjected to PWM according to an occurrence ratio for each predetermined phase angle for reducing the number of actuations of the first and second bidirectional switches.
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15. An AC-DC converter comprising:
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a rectifier connected to an AC power supply via a reactor; a plurality of capacitors connected in series across output terminals of the rectifier; a voltage detector for detecting a voltage across the capacitor connected to a negative terminal side of the rectifier; a first bidirectional switch having one end connected to one input terminal of the rectifier and another end connected to a connecting point between a plurality of capacitors; a second bidirectional switch having one end connected to the other input terminal of the rectifier and another end connected to the other end of the first bidirectional switch; and control means for actuating the first and second bidirectional switches during a half cycle of the AC power supply so as to control a voltage input to the rectifier to obtain a desired value of an output voltage, wherein the control means causes each of the following four modes to occur during a half cycle of an AC power supply; a full-wave rectification mode in which both the first and second bidirectional switches are turned off, a first voltage doubler rectification mode in which the first bidirectional switch is turned on and the second bidirectional switch is turned off, a second voltage doubler rectification mode in which the first bidirectional switch is turned off and the second bidirectional switch is turned on, and a power supply short-circuiting mode in which both the first and second bidirectional switches are turned on, and calculates a voltage across the other capacitor from the voltage across the capacitor detected by the voltage detector and the output voltage and controls an occurrence ratio of the first voltage doubler rectification mode and the second voltage doubler rectification mode so that these voltage differences across capacitors become small.
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Specification