Power supply device and air conditioner

A power supply device includes a first rectifying unit that converts the AC power passed through an input unit into DC power, a power-factor improving unit that improves a power factor of the DC power output from the first rectifying unit, a first power storage unit that stores the DC power passed through the power-factor improving unit and supplies the stored DC power to a load side, a second rectifying unit connected to a portion where the input unit is connected to the AC power supply, the second rectifying unit converting the AC power into the DC power, a second power storage unit that stores the DC power passed through the second rectifying unit, and a control unit that operates using the electric power stored in the second power storage unit and, when a short-circuit failure occurs in the power-factor improving unit, performs control for interrupting the input unit.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of International Patent Application No. PCT/JP2015/060220 filed on Mar. 31, 2015, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a power supply device that receives an input of AC power and drives a load and an air conditioner including the power supply device.

BACKGROUND

As a power supply device that receives an input of AC power and drives an electric motor, there has been a power supply device including one route to which electric power for driving the electric motor is input and another route to which electric power for driving a control unit, which controls the power supply device, is input.

A power supply circuit described in Patent Literature 1 described below includes a first converting unit11and a second converting unit12that convert an AC voltage into a DC voltage. The second converting unit12includes a diode D121. An anode of the diode D121is connected to between an input line L1and a switch unit S1. A cathode of the diode D121is connected to a capacitor C1that supplies a DC voltage applied to a control unit22. The second converting unit12performs half-wave rectification of an AC voltage and charges the capacitor C1. The power supply circuit can supply operation power to the control unit22even after the switch unit S1becomes nonconductive (paragraph 0050 to paragraph 0051 and FIG. 2).

PATENT LITERATURE

A power supply device that receives an input of AC power and drives an electric motor performs, at high speed, switching of a semiconductor switch element in a power converting unit for driving the electric motor or a power-factor improving unit for reducing power supply harmonics. Therefore, for the purpose of suppression of a leak of harmonic noise to a reception side, the power supply device includes a noise filter in an input unit to which AC power is input. To suppress noise in a normal mode, the noise filter often includes a capacitor that connects terminals of the input unit. The voltage of an AC power supply is directly applied to both ends of the capacitor.

When a short-circuit failure occurs in the semiconductor switch element included in the power-factor improving unit, to protect the electric motor or the power converting unit that drives the electric motor, a switch unit in the input unit is sometimes made nonconductive. At this point, the voltage applied to the capacitor is superimposed on, through a route not passing through the switch unit, a power storage unit for driving the control unit.

At this point, the voltage of the input unit at a point in time when the switch unit becomes nonconductive is directly superimposed on the power storage unit for driving the control unit. Therefore, a maximum voltage applied to the power storage unit for driving the control unit is approximately twice as large as a voltage during a normal operation. Therefore, a withstand voltage of components of the power storage unit for driving the control unit needs to be set to be twice or more as large as the voltage during the normal operation. There is a problem in that an increase in costs is caused.

SUMMARY

The present invention has been devised in view of the above and it is an object of the present invention to obtain a power supply device, the costs of which can be reduced.

In order to solve the above problem, and in order to attain the above object, a power supply device of the present invention includes: an input unit to which AC power is input from an AC power supply; a first rectifying unit that converts the AC power passed through the input unit into DC power; a power-factor improving unit that improves a power factor of the DC power output from the first rectifying unit; a first power storage unit that stores the DC power passed through the power-factor improving unit and supplies the stored DC power to a load side; a second rectifying unit connected to a portion where the input unit is connected to the AC power supply, the second rectifying unit converting the AC power into the DC power; a second power storage unit that stores the DC power passed through the second rectifying unit; and a control unit that operates using the electric power stored in the second power storage unit and, when a short-circuit failure occurs in the power-factor improving unit, performs control for interrupting the input unit.

Advantageous Effects of Invention

The power supply device according to the present invention achieves an effect that it is possible to reduce costs.

DETAILED DESCRIPTION

Power supply devices and an air conditioner according to embodiments of the present invention are explained in detail below with reference to the drawings. Note that the present invention is not limited by the embodiments.

First Embodiment

FIG. 1is a diagram showing the configuration of a power supply device according to a first embodiment. A power supply device1converts AC power supplied from an AC power supply2into DC power, further converts the DC power into AC power, and drives an electric motor3, which is a load.

The power supply device1includes an input unit4to which AC power is input from the AC power supply2. The input unit4includes a switch unit41, one end of which is connected to one end of the AC power supply2, and a noise filter42connected to the other end of the switch unit41and the other end of the AC power supply2.

Note that, in the first embodiment, a connecting portion of the one end of the AC power supply2and the one end of the switch unit41is referred to as terminal L and a connecting portion of the other end of the AC power supply2and the noise filter42is referred to as terminal N.

The noise filter42includes a coil421, which is an inductive element, and a capacitor422, which is a capacitive element. One end of the coil421is connected to the terminal N. One end of the capacitor422is connected to the other end of the first switch unit41. The other end of the capacitor422is connected to the other end of the coil421. The switch unit41is in an OFF state at an initial time.

The coil421can suppress a leak of high-frequency noise in a normal mode, can suppress noise in a common mode, and can suppress noise in both of the normal mode and the common mode.

When the switch unit41is in an OFF state, the one end of the capacitor422and the terminal L are disconnected. Therefore, the first switch unit41has a function of suppressing reactive power generated when AC power is supplied to the capacitor422.

The power supply device1includes a first rectifying unit5that converts AC power passed through the input unit4into DC power. A diode bridge is illustrated as the first rectifying unit5.

The power supply device1includes a power-factor improving unit6that improves a power factor of DC power output from the first rectifying unit5, reduces power supply harmonics of a DC voltage output from the first rectifying unit5, and boosts the DC voltage output from the first rectifying unit5.

The power-factor improving unit6includes a reactor61, one end of which is connected to an output end on a high-potential side of the first rectifying unit5. The reactor61is an inductive element that stores energy generated by an electric current passed through the first rectifying unit5.

The power-factor improving unit6includes a semiconductor switch element62, one end of which is connected to the other end of the reactor61. The semiconductor switch element62causes a power-supply short-circuit to feed a short-circuit current to the reactor61.

The power-factor improving unit6includes a diode63, an anode of which is connected to the other end of the reactor61. The diode63is a rectifying element that supplies the energy stored in the reactor61to a first power storage unit7.

The reactor61, the semiconductor switch element62, and the diode63configure a boost chopper circuit.

The power-factor improving unit6includes a current detecting unit64connected between the semiconductor switch element62and an output end on a low-potential side of the first rectifying unit5. The current detecting unit64detects an electric current flowing to the semiconductor switch element62.

The power supply device1includes the first power storage unit7that stores DC power passed through the power-factor improving unit6. A capacitor is illustrated as the first power storage unit7. The DC power stored in the first power storage unit7is supplied to a load side.

The power supply device1includes a power converting unit8that converts the DC power stored in the first power storage unit7into AC power having a desired voltage and a desired frequency and supplies the AC power to the electric motor3. A three-phase inverter circuit is illustrated as the power converting unit8.

The power supply device1includes a charging unit21connected between the terminal N and one end on the high-potential side of the first power storage unit7. The charging unit21can store DC power in the first power storage unit7not through the noise filter42.

The charging unit21is configured by connecting a charging switch unit211, a charging resistor212, which is a resistive element, and a diode213, which is a rectifying element, in series. The charging switch unit211is in an OFF state at the initial time.

When the charging switch unit211is in an ON state, an electric current flows through a route of the terminal L, the charging switch unit211, the charging resistor212, the diode213, the first power storage unit7, and the terminal N. Electric power is stored in the first power storage unit7.

The charging resistor212has a function of suppressing a rush current that flows when electric power is stored in the first power storage unit7. Consequently, it is unnecessary to connect a charging resistor to the switch unit41in parallel.

The power supply device1includes a second rectifying unit11that converts AC power of the AC power supply2into DC power and a second power storage unit12in which the DC power passed through the second rectifying unit11is stored.

The second rectifying unit11includes a diode111, which is a rectifying element. A capacitor, which is a capacitive element, is illustrated as the second power storage unit12. An anode of the diode111is connected to the terminal L. A cathode of the diode111is connected to one end on the high-potential side of the second power storage unit12. The other end on the low-potential side of the second power storage unit12is connected to the terminal N through the power-factor improving unit6, the first rectifying unit5, and the input unit4.

The power supply device1includes a control unit13that controls the switch unit41, the semiconductor switch element62, and the charging switch unit211to the ON state and the OFF state and controls the power converting unit8. The control unit13operates using the DC power stored in the second power storage unit12. The electric current detected by the current detecting unit64in the power-factor improving unit6is input to the control unit13.

FIG. 2is a flowchart for explaining the operation of the power supply device according to the first embodiment. When AC power is supplied from the AC power supply2, the power supply device1executes the operation shown inFIG. 2.

When AC power is supplied from the AC power supply2to the power supply device1, at step S100, an electric current flows through a route that passes through the terminal L, the second rectifying unit11, the second power storage unit12, and the terminal N. Electric power is stored in the second power storage unit12. The DC power is stored in the second power storage unit12is only in a period in which the potential of the terminal L is higher than the potential of the terminal N. Therefore, a rectifying operation by the second rectifying unit11and the first rectifying unit5is half-wave rectification.

When the DC power is stored in the second power storage unit12, at step S102, the control unit13starts an operation using the DC power stored in the second power storage unit12. Note that, at this point, DC power is not stored in the first power storage unit7.

At step S104, the control unit13controls the charging switch unit211to the ON state. Consequently, an electric current flows through a route that passes through the terminal L, the charging switch unit211, the charging resistor212, the diode213, the first power storage unit7, and the terminal N. Electric power is stored in the first power storage unit7.

When the electric power is stored in the first power storage unit7, the first power storage unit7can feed power to the second power storage unit12through the diode9.

At step S106, the control unit13controls the switch unit41to the ON state. At this point, the control unit13controls the charging switch unit211to the OFF state. Consequently, electric power is supplied to the first power storage unit7through a route that passes through the noise filter42, the first rectifying unit5, and a power-factor improving unit6. Consequently, suppression of a leak of high-frequency noise by the noise filter42, improvement of a power factor by ON or OFF control of the semiconductor switch element62, and boosting of a DC voltage are performed.

At step S108, the control unit13starts control of the power converting unit8. Consequently, the electric motor3is driven.

FIG. 3is a flowchart for explaining the operation of the power supply device according to the first embodiment. The control unit13executes processing shown inFIG. 3during a control operation.

When the semiconductor switch element62and the power converting unit8are controlled by the control unit13, if a short-circuit failure of the semiconductor switch element62occurs, the current detecting unit64detects a short-circuit current.

At step S200, the control unit13determines whether an electric current larger than a threshold set in advance is detected by the current detecting unit64. When determining that an electric current larger than the threshold is not detected by the current detecting unit64(No), the control unit13stays on standby at step S200.

When determining that an electric current larger than the threshold is detected by the current detecting unit64(Yes), the control unit13advances the processing to step S202.

At step S202, the control unit13stops the control of the power converting unit8and controls the switch unit41to the OFF state. Consequently, the power supply device1can suppress a failure of the power converting unit8due to an excessively large current or voltage.

When the switch unit41is controlled to the OFF state, a route in which the one end of the capacitor422is connected to the second power storage unit12through the second rectifying unit11is interrupted. That is, the voltage of the capacitor422is not superimposed on the second power storage unit12.

On the other hand, even if the switch unit41is controlled to the OFF state, the AC power of the AC power supply2is rectified to DC power through a route of the terminal L, the second rectifying unit11, the second power storage unit12, and the terminal N. Irrespective of a short-circuit failure of the semiconductor switch element62, the DC power is supplied to the second power storage unit12. Therefore, the control unit13does not stop the operation.

As explained above, in the power supply device1according to the first embodiment, the second rectifying unit11is configured by the diode111, the anode of which is connected to the terminal L and the cathode of which is connected to the second power storage unit12. Consequently, even when a short-circuit failure of the semiconductor switch element62occurs, a route in which the voltage of the capacitor422is superimposed on the second power storage unit12is suppressed by the second rectifying unit11. Therefore, the power supply device1does not need to set a withstand voltage of the second power storage unit12to be twice or more as large as a voltage at normal time. Consequently, in the power supply device1, it is possible to reduce costs of the second power storage unit12.

The AC power of the AC power supply2is supplied to the second power storage unit12through a route unrelated to the short-circuit failure of the semiconductor switch element62. Consequently, the operation of the control unit13is not stopped. The power supply device1can continue the operation.

Second Embodiment

In the first embodiment, a rush current flows to the second rectifying unit11when power storage in the second power storage unit12through the second rectifying unit11is started. When a large rush current flows to the diode111in the second rectifying unit11, it is likely that the diode111fails. Therefore, to achieve a reduction in the size of the diode111, it is necessary to achieve suppression of the rush current. A second embodiment achieves suppression of the rush current to the diode111.

FIG. 4is a diagram showing the configuration of a power supply device according to the second embodiment. A power supply device1A further includes, in the configuration of the power supply device1according to the first embodiment, a second charging resistor141connected to the second rectifying unit11in series when an electric current flows and a second charging switch unit142controlled by the control unit13to switch a route of an electric current flowing to the second rectifying unit11to a route that passes through the second charging resistor141or a route that does not pass through the second charging resistor141.

One end of the second charging resistor141is connected to the terminal L. One end of the second charging switch unit142is connected to the anode of the diode111. The other end of the second charging switch unit142is switched and connected to a contact A on the one end side of the second charging resistor141or a contact B on the other end side of the second charging resistor141. The second charging switch unit142is connected to the contact B side at initial time.

FIG. 5is a flowchart for explaining the operation of the power supply device according to the second embodiment. When AC power is supplied from the AC power supply2, the power supply device1A executes an operation shown inFIG. 5.

Steps S100, S102, S104, S106, and S108of the flowchart shown inFIG. 5are the same as the steps of the flowchart shown inFIG. 2according to the first embodiment. The flowchart shown inFIG. 5includes step S103between step S102and step S104.

When AC power is supplied from the AC power supply2to the power supply device1, at step S100, an electric current flows through a route that passes through the terminal L, the second charging resistor141, the second charging switch unit142, the second rectifying unit11, the second power storage unit12, and the terminal N. Electric power is stored in the second power storage unit12.

At this point, because the second charging resistor141is present in the route through which a direct current flows, a rush current flowing to the second power storage unit12passes through the second charging resistor141. Therefore, a peak value of the rush current is suppressed by the second charging resistor141. Consequently, it is possible to suppress a large current from flowing to the diode111of the second rectifying unit11.

When DC power is stored in the second power storage unit12, at step S102, the control unit13starts an operation using the DC power stored in the second power storage unit12.

At step S103, the control unit13performs control for switching the second charging switch unit142such that the other end of the second charging switch unit142is connected to the contact A. Consequently, the control unit13switches a route of an electric current for storing electric power in the second power storage unit12to a route that does not pass through the second charging resistor141and passes through the terminal L, the second charging switch unit142, the second rectifying unit11, the second power storage unit12, and the terminal N.

In a period in which DC power is not stored in the first power storage unit7, supply of the DC power to the second power storage unit12is performed through the route that passes through the second rectifying unit11. At step S103, the supply of the DC power to the second power storage unit12is performed through the route that does not pass through the second charging resistor141, whereby a power loss in the second charging resistor141is suppressed.

Explanation of step S104and subsequent steps is omitted because the steps are the same as the steps in the first embodiment.

As explained above, the power supply device1A according to the second embodiment includes the second charging resistor141. Therefore, it is possible to suppress a large current from flowing to the second rectifying unit11. Consequently, in the power supply device1A, it is possible to reduce the size of the diode111of the second rectifying unit11. Therefore, in the power supply device1A, it is possible to reduce the costs of the second rectifying unit11.

When the control unit13starts an operation using the DC power stored in the second power storage unit12, the control unit13performs control for switching the second charging switch unit142such that the other end of the second charging switch unit142is connected to the contact A. Consequently, the control unit13switches a route of an electric current for storing electric power in the second power storage unit12to a route that does not pass through the second charging resistor141and passes through the terminal L, the second charging switch unit142, the second rectifying unit11, the second power storage unit12, and the terminal N. Therefore, in the power supply device1A, it is possible to suppress a power loss in the second charging resistor141.

Note that the second charging resistor141only has to be disposed to be connected to the second rectifying unit11in series when an electric current flows to the second charging resistor141. Specifically, the second charging resistor141can be disposed between the second rectifying unit11and the second power storage unit12.

The connection of the second charging resistor141and the second charging switch unit142is not limited to the configuration shown inFIG. 4.

FIG. 6is a diagram showing the configuration of another example of the power supply device according to the second embodiment. In a power supply device1B, the second charging resistor141is connected in series between the second rectifying unit11and the second power storage unit12. The second charging switch unit142is connected to the second charging resistor141in series. The second charging switch unit142is in the OFF state at initial time.

When AC power is supplied from the AC power supply2to the power supply device1, an electric current flows through a route that passes through the terminal L, the second rectifying unit11, the second charging resistor141, the second power storage unit12, and the terminal N. Electric power is stored in the second power storage unit12.

At this point, because the second charging resistor141is present in the route through which a direct current flows, a rush current flowing to the second power storage unit12passes through the second charging resistor141. Therefore, a peak value of the rush current is suppressed by the second charging resistor141. Consequently, it is possible to suppress a large current from flowing to the diode111of the second rectifying unit11.

When DC power is stored in the second power storage unit12, the control unit13starts an operation using the DC power stored in the second power storage unit12.

After starting the operation, the control unit13performs control for switching the second charging switch unit142to the ON state. Consequently, the control unit13switches the route of the electric current for storing electric power in the second power storage unit12to a route that does not pass through the second charging resistor141and passes through the terminal L, the second rectifying unit11, the second charging switch unit142, the second power storage unit12, and the terminal N.

In a period in which DC power is not stored in the first power storage unit7, supply of the DC power to the second power storage unit12is performed through the route that passes through the second rectifying unit11. The supply of the DC power to the second power storage unit12is performed through the route that does not pass through the second charging resistor141, whereby a power loss in the second charging resistor141is suppressed.

As explained above, the power supply device1B according to the second embodiment includes the second charging resistor141. Therefore, it is possible to suppress a large current from flowing to the second rectifying unit11. Consequently, in the power supply device1B, it is possible to reduce the size of the diode111of the second rectifying unit11. Therefore, in the power supply device1B, it is possible to reduce the costs of the second rectifying unit11.

When the control unit13starts an operation using the DC power stored in the second power storage unit12, the control unit13performs control for switching the second charging switch unit142to the ON state. Consequently, the control unit13switches the route of the electric current for storing electric power in the second power storage unit12to the route that does not pass through the second charging resistor141and passes through the terminal L, the second charging switch unit142, the second rectifying unit11, the second power storage unit12, and the terminal N. Therefore, in the power supply device1B, it is possible to suppress a power loss in the second charging resistor141.

Note that the second charging resistor141only has to be disposed to be connected to the second rectifying unit11in series. Specifically, the second charging resistor141can be disposed between the terminal L and the second rectifying unit11.

Third Embodiment

FIG. 7is a diagram showing the configuration of an air conditioner according to a third embodiment. An air conditioner30includes a power supply device1C and indoor units31A and31B.

In the power supply device1C, a circuit for connecting the power supply device1C to the indoor units31A and31B is added to the configuration of the power supply device1B according to the second embodiment. The power supply device1C further includes, in addition to the components of the power supply device1B, an indoor-unit connecting unit33including a plurality of terminals to which the indoor units31A and31B are connected, communication-circuit transmitting units52A and53A and communication-circuit receiving units52B and53B for communicating with the indoor units31A and31B, a communication-power generating unit51that generates electric power used by the communication-circuit transmitting units52A and53A and the communication-circuit receiving units52B and53B, and diodes52C and52E and53C and53D.

The indoor-unit connecting unit33includes terminals S1, S2, S3, S4, S5, and S6. The terminal S1is connected to the terminal L. The terminal S2is connected to the terminal N. AC power is supplied to the indoor unit31A through the terminals S1and S2. The terminal S4is connected to the terminal L via the terminal S1. The terminal S5is connected to the terminal N via the terminal S2. AC power is supplied to the indoor unit31B through the terminals S4and S5.

The communication-power generating unit51generates, using AC power supplied through the terminal S1and the terminal S2, electric power used by the communication-circuit transmitting units52A and53A and the communication-circuit receiving units52B and53B.

An anode of the diode52C is connected to the communication-circuit receiving unit52B and a cathode of the diode52C is connected to the terminal S3. An anode of the diode53C is connected to the communication-circuit receiving unit53B and a cathode of the diode53C is connected to the terminal S6.

An anode of the diode52D is connected to the terminal S3. An anode of the diode53D is connected to the terminal S6. A cathode of the diode52D and a cathode of the diode53D are connected in common and connected to the one end of the second charging resistor141.

Note that, in the power supply device1C, unlike the power supply device1A according to the second embodiment, the one end of the second charging resistor141is not connected to the terminal L.

FIG. 8is a flowchart for explaining the operation of the air conditioner according to the third embodiment.

When AC power is supplied to the air conditioner30, because a current route for storing DC power in the first power storage unit7and the second power storage unit12is not formed, DC power is not stored in the first power storage unit7and the second power storage unit12. Because electric power is not supplied to the control unit13, the control unit13does not start an operation. Therefore, the other end of the second charging switch unit142stays in an initial state in which the other end is connected to the terminal B on the second charging resistor141side. On the other hand, electric power is supplied to the indoor unit31A via the terminals S1and S2and electric power is supplied to the indoor unit31B via the terminals S4and S5.

When the air conditioner30starts the operation, at step S300, the indoor unit31A performs control for short-circuiting the terminal S1and the terminal S3in the indoor-unit connecting unit33by connecting contacts included in the inside of the indoor unit31A. Alternatively, at step S300, the indoor unit31B performs control for short-circuiting the terminal S4and the terminal S6in the indoor-unit connecting unit33by connecting contacts included in the inside of the indoor unit31B.

When the terminal S1and the terminal S3in the indoor-unit connecting unit33are short-circuited, at step S302, an electric current flows through a route that passes through the terminal L, the terminal S1, the terminal S3, the diode52D, the second charging resistor141, the second rectifying unit11, the second power storage unit12, and the terminal N. Electric power is stored in the second power storage unit12. Alternatively, when the terminal S4and the terminal S6in the indoor-unit connecting unit33are short-circuited, at step S302, an electric current flows through a route that passes through the terminal L, the terminal S4, the terminal S6, the diode53D, the second charging resistor141, the second rectifying unit11, the second power storage unit12, and the terminal N. Electric power is stored in the second power storage unit12.

At this point, because the second charging resistor141is present in the route through which a direct current flows, a rush current flowing to the second power storage unit12passes through the second charging resistor141. Therefore, a peak value of the rush current is suppressed by the second charging resistor141. Consequently, it is possible to suppress a large current from flowing to the diode111of the second rectifying unit11.

When DC power is stored in the second power storage unit12, at step S304, the control unit13starts an operation using the DC power stored in the second power storage unit12.

At step S306, the control unit13performs control for switching the second charging switch unit142such that the other end of the second charging switch unit142is connected to the contact A. Consequently, the control unit13switches a route of an electric current for storing electric power in the second power storage unit12to a route that does not pass through the second charging resistor141and passes through the terminal L, the second charging switch unit142, the second rectifying unit11, the second power storage unit12, and the terminal N.

In a period in which DC power is not stored in the first power storage unit7, supply of DC power to the second power storage unit12is performed through the route that passes through the second rectifying unit11. At step S306, the supply of the DC power to the second power storage unit12is performed through the route that does not pass through the second charging resistor141, whereby a power loss in the second charging resistor141is suppressed.

At step S308, to perform exchange of communication signals between the indoor unit31A and the control unit13via the terminal S3, the indoor unit31A opens the contacts included in the inside of the indoor unit31A to thereby perform an operation for opening the terminal S1and the terminal S3in the indoor-unit connecting unit33. Alternatively, at step S308, to perform exchange of communication signals between the indoor unit31B and the control unit13via the terminal S6, the indoor unit31B opens the contacts included in the inside of the indoor unit31B to thereby perform an operation for opening the terminal S4and the terminal S6in the indoor-unit connecting unit33.

At this point, because the route of the electric current for storing electric power in the second power storage unit12is formed to pass through the terminal L, the second charging switch unit142, the second rectifying unit11, the second power storage unit12, and the terminal N, the control unit13can continue the operation.

Explanation of steps S310, S312, and S314is omitted because the steps are the same as steps S104, S106, and S108inFIG. 5.

When the operation of the air conditioner30is not performed, DC power is not stored in the second power storage unit12and the control unit13does not operate. Therefore, only the indoor units31A and31B consume electric power when the operation of the air conditioner30is not performed. In the power supply device1C, it is possible to suppress power consumption.

As explained above, the air conditioner30according to the third embodiment is configured by the power supply device1C and the indoor units31A and31B. The diodes52D and53D are connected to the circuit that performs transmission and reception of communication signals between the indoor units31A and31B and the control unit13. The cathodes of the diodes52D and53D are connected to the second charging resistor141. Consequently, when the operation of the air conditioner30is not performed, DC power is not stored in the second power storage unit12and the control13does not operate. Therefore, in the power supply device1C, it is possible to reduce power consumption.

When the operation of the air conditioner30is started, DC power is stored in the second power storage unit12by operations of the contacts on the inside of the indoor units31A and31B. The control unit13can start an operation. Further, the control unit13switches the contacts of the second charging switch unit142and forms a route for supplying DC power from the terminal L to the second power storage unit12. Therefore, it is possible to continue the operation irrespective of the operations of the contacts on the inside of the indoor units31A and31B after that.

The configurations explained in the embodiments above indicate an example of contents of the present invention and can be combined with other publicly-known technologies. A part of the configurations can be omitted or changed in a range not departing from the spirit of the present invention.