JP2009038848A - Power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply circuit for an air conditioner or a heat pump type hot water supply apparatus, in which a first smoothing capacitor is discharged surely while controlling loss as much as possible during operation even when an AC power supply is interrupted and an inverter circuit is stopping. <P>SOLUTION: Since a first smoothing capacitor 6 is connected with a second smoothing capacitor 7 through diodes 8 and 9 in the direction of a current flowing from the first smoothing capacitor to the second smoothing capacitor, the first smoothing capacitor 6 is discharged surely even if an inverter circuit 13 stops. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply circuit of an air conditioner or a heat pump type hot water heater.

  A power supply circuit for a conventional air conditioner is shown in FIG.

  8 and 9 are diodes, and the diode 8 is connected in the direction in which current flows from the negative side of the DC output end of the second bridge rectifier circuit 5 to the negative side of the DC output end of the first bridge rectifier circuit. 9 is connected in the direction in which current flows from the plus side of the DC output end of the first bridge rectifier circuit 4 to the plus side of the DC output end of the second bridge rectifier circuit 4. Further, by inserting the switch 2 between the reactor 3 and the AC power source 1 and shutting off the switch 2 by the switch driving means 12 provided in the control device 15, leakage when the compressor 14 is not driven is performed. Reduce current.

  When the power source 1 is cut off, the charge charged in the second smoothing capacitor 7 is consumed by the DC-DC converter circuit 10, and the DC voltage of the second smoothing capacitor 7 is changed to the direct current of the first smoothing capacitor 6. At the same time as the voltage drops, the charge charged in the first smoothing capacitor 6 is consumed by the DC-DC converter circuit 10 via the diode 9 and the diode 8.

As described above, by connecting the first smoothing capacitor 6 and the second smoothing capacitor 7 via the diodes 8 and 9, even if the power supply 1 is shut off in a state where the inverter circuit 13 is stopped, the first smoothing capacitor 6 and the second smoothing capacitor 7 are connected. The electric charge stored in the smoothing capacitor 6 can be discharged. For example, it is not necessary to provide a special discharge means for repair or the like, and a simple and safe repair work can be performed.
JP 2006-109558 A

  However, in the above conventional configuration, in order to avoid energizing the inverter circuit at all times, the switch is opened when the operation is stopped, but both elements of the switch are always driven during operation, so both elements are driven. Since the electric power to make is required, the operation efficiency is impaired.

  The present invention has been made in view of the conventional problems, and provides a power supply circuit capable of quickly discharging the first smoothing capacitor while reducing the power for driving the switch during operation. Objective.

In order to solve the above-described conventional problems, a power circuit according to the present invention includes a reactor connected to a power line on one side of an AC power source, a first switch on the other side of the AC power source, and a second switch in parallel with the first switch. And a positive polarity thermistor connected in series, and a first bridge rectifier circuit formed of four diodes that rectify full-wave direct current through a reactor, and four diodes that directly rectify full-wave from the AC power source And a first smoothing capacitor and a second smoothing capacitor connected to the DC output terminals of the first bridge rectifier circuit and the second bridge rectifier circuit, respectively. An inverter circuit is connected to the DC output terminal of the first bridge rectifier circuit to drive the compressor, and a DC-DC converter circuit is connected to the DC output terminal of the second bridge rectifier circuit. A power supply circuit that supplies power to a control device having a barter circuit driving means, and is connected from the positive side of the DC output end of the first bridge rectifier circuit to the positive side of the DC output end of the second bridge rectifier circuit. The first diode is connected to the first diode, and the second diode and the first negative polarity are connected from the negative side of the DC output end of the second bridge rectifier circuit toward the negative side of the DC output end of the first bridge rectifier circuit. A thermistor is connected in series and has a third current limiting element from the negative electrode side of the second smoothing capacitor toward the second bridge rectifier circuit.

  Accordingly, it is possible to quickly discharge the first smoothing capacitor even when the switch is in an open state while reducing the drive of the switch during operation.

  The power supply circuit of the present invention can quickly discharge the first smoothing capacitor while reducing the power for driving the switch during operation.

  A reactor is connected to a power supply line on one side of the AC power supply, and a first switch and a second switch and a positive polarity thermistor are connected in series to the other side of the AC power supply in parallel. A first bridge rectifier circuit formed of four diodes for full-wave rectification, a second bridge rectifier circuit formed of four diodes for full-wave rectification directly from the AC power supply, and the first bridge A first smoothing capacitor and a second smoothing capacitor connected to the DC output terminal of the rectifier circuit and the second bridge rectifier circuit, respectively, and an inverter circuit is connected to the DC output terminal of the first bridge rectifier circuit; Connected to drive the compressor, and a DC-DC converter circuit is connected to the DC output terminal of the second bridge rectifier circuit to supply power to a control device having inverter circuit driving means. A first diode is connected from the positive side of the DC output end of the first bridge rectifier circuit toward the positive side of the DC output end of the second bridge rectifier circuit, and the second bridge A second diode and a first negative thermistor are connected in series from the negative side of the DC output end of the rectifier circuit to the negative side of the DC output end of the first bridge rectifier circuit, and the negative side of the second smoothing capacitor By having the third current limiting element from the first to the second bridge rectifier circuit, the driving of the switch is reduced during operation and the first smoothing capacitor is discharged even when the switch is open. This can be done quickly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a configuration diagram of an air conditioner using a power supply circuit according to Embodiment 1 of the present invention. In FIG. 1, the same components as those in FIG.

  First, the operation during operation will be described. When power is applied to the AC power supply 1, the second switch 17 is closed by the opening / closing means 12 of the control unit 15, and the first smoothing capacitor 6 is charged through the positive polarity thermistor 18. The first switch 16 is closed after the charging is sufficient. Thereafter, the second switch 17 is opened to prevent the inrush current to the first bridge rectifier circuit 4 and the first smoothing capacitor 6 and reduce the drive loss of the switch that occurs during operation. It becomes possible to do.

Next, the operation when the operation is stopped will be described. First, the role of the first and second negative-polarity thermistors 19 and 20 will be described. By reducing the drive loss of the switch, the power line of the first bridge rectifier circuit 4 and the AC power supply 1 is connected. For example, when the AC power supply 1 is applied and the first and second diodes 8 and 9 are not present until the operation of the switch described above, the second smoothing capacitor 7 is provided. Charging current passes through a loop of AC power source 1 to second rectifier circuit 5 to second negative polarity thermistor 20 to second rectifier circuit to AC power source 1. There is no problem because the inrush current to the second rectifier circuit 5 and the second smoothing capacitor 7 is limited by the second negative polarity thermistor 20.

  However, since the power supply circuit of the present invention is connected by the first and second diodes 8 and 9 in order to discharge the electric charge of the first smoothing capacitor 6, there are two charging loops that do not pass through the second negative polarity thermistor 20. Species exist. The charging loop 1 is charged by a loop of an AC power source 1 to a second rectifier circuit 5 to a second smoothing capacitor 7 to a first diode 8 to a first bridge rectifier circuit to a reactor 3 to an AC power source 1. At this time, the inrush current is limited to some extent in the reactor 3, but the limited current value varies depending on the impedance of the reactor 3. In addition, when the reactor 3 is short-circuited, it cannot be expected to limit the current. Therefore, the power supply circuit of the present invention can reliably limit the inrush current in the charging loop 1 by connecting the first negative polarity thermistor 19 in series with the first diode 8.

  Next, the case of the charging loop 2 will be described. If the reactor 3 is short-circuited, the charging loop 2 includes the AC power source 1 to the reactor 3 (short-circuited state) to the first bridge rectifier circuit 4 to the second diode 9 to the second smoothing capacitor 7 to the second bridge. It is charged by the loop of the rectifier circuit 5 to the AC power source 1. At this time, since the second negative polarity thermistor 20 is connected between the charging loops 2, it is possible to reliably limit the inrush current in the charging loop 2.

  Next, the discharging operation of the first smoothing capacitor 6 will be described. When the AC power supply 1 is cut off, or when the compressor 14 is stopped, the drive of the inverter circuit 13 is stopped, and the second opening / closing means 16 is opened, the second smoothing capacitor 7 is charged. The electric charge is consumed by the DC-DC converter circuit 10 and the DC voltage of the second smoothing capacitor 7 is lower than the DC voltage of the first smoothing capacitor 6. Is consumed by the DC-DC converter circuit 10 via the second diode 9 and the first diode 8.

  As described above, in the present embodiment, the charge stored in the first smoothing capacitor when the operation is stopped is reduced while reducing the inrush current when the power is turned on while reducing the switching unit driving loss that occurs during the operation. It is possible to discharge quickly, and for example, it is not necessary to provide a special discharge means for repair or the like, and it is possible to perform simple and safe repair work.

  As described above, since the power supply circuit according to the present invention can quickly discharge the first smoothing capacitor when the AC power supply is cut off, the heat pump performs the repair work by cutting off the AC power supply. This is useful for applications such as water heaters and air conditioners.

The block diagram of the air conditioner using the power supply device in Embodiment 1 of this invention Configuration diagram of conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Switch 3 Reactor 4 1st bridge rectifier circuit 5 2nd bridge rectifier circuit 6 1st smoothing capacitor 7 2nd smoothing capacitor 8 1st diode 9 2nd diode 10 DC-DC converter circuit DESCRIPTION OF SYMBOLS 11 Inverter circuit drive means 12 Switch drive means 13 Inverter circuit 14 Compressor 15 Control device 16 1st switch 17 2nd switch 18 Positive polarity thermistor 19 1st negative polarity thermistor 20 2nd negative polarity thermistor

Claims (1)

A reactor is connected to the power line on one side of the AC power source, and a first switch and a second switch and a positive polarity thermistor are connected in series to the other side of the AC power source in parallel. A first bridge rectifier circuit formed of four diodes for full-wave rectification, a second bridge rectifier circuit formed of four diodes for full-wave rectification directly from the AC power supply, and the first bridge A first smoothing capacitor and a second smoothing capacitor connected to a DC output terminal of the rectifier circuit and the second bridge rectifier circuit, respectively, and an inverter circuit is connected to the DC output terminal of the first bridge rectifier circuit; Connected to drive the compressor, and a DC-DC converter circuit is connected to the DC output terminal of the second bridge rectifier circuit to supply power to the control device having inverter circuit driving means. A first diode is connected from the positive side of the DC output end of the first bridge rectifier circuit toward the positive side of the DC output end of the second bridge rectifier circuit, and the second bridge rectifier A second diode and a first negative thermistor are connected in series from the negative side of the DC output end of the circuit to the negative side of the DC output end of the first bridge rectifier circuit, and from the negative side of the second smoothing capacitor. A power supply circuit comprising a third current limiting element connected to the second bridge rectifier circuit.

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