Air conditioner

Abstract

The outdoor unit includes a converter, a capacitor, an element for preventing an inrush current, a light-emitting element, a switch, an on-off switch, and an outdoor controller. The outdoor controller operates in accordance with the voltage of the capacitor, closes the on-off switch after a predetermined time from the start of the operation, and opens the on-off switch when the operation of the outdoor unit is not required. The indoor unit includes an indoor controller. The indoor controller continuously transmits a signal to the signal line when the operation of the outdoor unit is required.

Description

[0001] This application is a divisional application of the Chinese patent application No. 201880094778.X filed by the applicant on July 19, 2018, entitled "Air Conditioner". Technical Field

[0002] Embodiments of the present invention relate to an air conditioner having an outdoor unit and an indoor unit and interconnecting the outdoor unit and the indoor unit via a signal line for data transmission. Background Technology

[0003] The outdoor unit of the air conditioner includes a converter that converts AC power voltage to DC power, a capacitor connected to the output of the converter, and an inverter that converts the voltage of the capacitor into AC voltage for load driving.

[0004] In such outdoor units, to prevent damage caused by large inrush currents flowing through the converter and capacitors when AC power is switched on, inrush current prevention components, such as positive characteristic thermistors, are inserted into the power lines between the AC power source and the converter. Furthermore, when current flows through the positive characteristic thermistor, its temperature rises and its resistance increases continuously, resulting in unnecessary power consumption or a reduction in the input current to the converter, preventing the inverter from driving. Therefore, a normally open switch is connected in parallel with the positive characteristic thermistor, which closes after a predetermined time has elapsed since power was switched on.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 3019844 Summary of the Invention

[0006] The technical problem solved by the invention Even when the outdoor unit is in a state where operation is unnecessary after power is turned on, the closed switch continues to supply power to the internal equipment of the outdoor unit, consuming electricity despite the unit being shut down. This standby power consumption during off-peak hours is a technical issue that needs improvement in terms of energy efficiency.

[0007] The purpose of this invention is to provide an air conditioner that can reduce standby power consumption.

[0008] Means for solving technical problems The air conditioner of technical solution 1 includes an outdoor unit and an indoor unit, which are interconnected by a signal line. The outdoor unit includes: a converter that converts AC power voltage to DC voltage; a capacitor connected to the output of the converter; an inrush current prevention element inserted into the power line between the AC power source and the converter; a light-emitting element that emits light according to a signal passing through the signal line; a switch inserted into the power line and forming a series circuit with the inrush current prevention element, and operating in response to the light emission of the light-emitting element; a normally open switch connected in parallel with the series circuit of the inrush current prevention element and the switch; and an outdoor controller that operates according to the voltage of the capacitor, closing the switch after a predetermined time from the start of operation, and opening the switch when operation of the outdoor unit is not required. The indoor unit includes an indoor controller that continuously sends signals to the signal line when operation of the outdoor unit is required.

[0009] Another air conditioner technology includes an outdoor unit and an indoor unit, which are interconnected via a serial signal line for data transmission. The outdoor unit comprises: a converter that converts AC power voltage to DC voltage; a capacitor connected to the output terminal of the converter; an inrush current prevention element inserted into a power line between the AC power source and the converter; a light-emitting element disposed on the serial signal line, emitting light according to a serial signal passing through the line; a switch inserted into the power line and forming a series circuit with the inrush current prevention element, which conducts upon illumination by the light-emitting element, thereby applying the AC power voltage to the converter through the inrush current prevention element; a normally open switch connected in parallel with the series circuit of the inrush current prevention element and the switch, which directly supplies the AC power voltage to the converter when closed; and a receiving unit, which... The system includes a serial signal line for receiving a serial communication signal transmitted from the indoor unit in sync with the half-wave voltage of the AC power supply; and an outdoor controller that operates based on the voltage of the capacitor to which the output voltage of the converter is applied, closing the switch after a predetermined time from the start of operation, and opening the switch when the operation of the outdoor unit is not required. The conduction of the switch is independent of the outdoor controller but is controlled solely by the serial signal transmitted from the indoor unit before the outdoor controller begins operation. The indoor unit includes a transmitting unit that transmits the serial signal to the outdoor unit via the serial signal line; and an indoor controller that, when the operation of the outdoor unit is required, continuously transmits the serial signal from the transmitting unit to the serial signal line to turn on the switch, causing the light-emitting element to emit light. After the switch is turned on according to the serial signal, and the capacitor is charged to a predetermined voltage or higher, the outdoor controller begins operation. Attached Figure Description

[0010] Figure 1 This is a block diagram illustrating the structure of the first embodiment.

[0011] Figure 2 This is a flowchart illustrating the control of the indoor controller in various implementation methods.

[0012] Figure 3 This is a timing diagram showing the operation of each part of the outdoor unit in the first embodiment.

[0013] Figure 4 This is a flowchart illustrating the control of the outdoor controller in various implementation methods.

[0014] Figure 5This is a block diagram showing the structure of the main parts of the second embodiment. Detailed Implementation

[0015] [1] The first embodiment will be described with reference to the accompanying drawings.

[0016] like Figure 1 As shown, the air conditioner consists of an outdoor unit 2 located outdoors and an indoor unit 60 located indoors.

[0017] The power terminals 3a and 3b of the external connection terminal 3 in the outdoor unit 2 are connected to the AC power supply 1. The power terminals 61a and 61b of the external connection terminal 61 in the indoor unit 60 are connected to these power terminals 3a and 3b via power cables C1 and C2. Furthermore, the communication terminal 3c of the external connection terminal 3 and the communication terminal 61c of the external connection terminal 61 are interconnected via a serial signal line (signal line) C3 for data transmission. Alternatively, the power terminals 61a and 61b of the external connection terminal 61 in the indoor unit 60 can be directly connected to the AC power supply 1 connected to the outdoor unit 2 without going through the power terminals 3a and 3b of the external connection terminal 3 in the outdoor unit 2. However, in this case, since the serial signal line C3 connecting the communication terminals 3c and 61c is routed in a crossed manner with the AC power line from the power terminals 61a and 61b to the AC power supply 1, care must be taken to avoid incorrect wiring.

[0018] [Structure of Outdoor Unit 2] Power lines L1 and L2 are led out from the power terminals 3a and 3b of the external connection terminal 3. A converter (first converter) 6 is connected to these power lines L1 and L2 via a noise filter 4. The converter 6 is, for example, a diode bridge rectifier circuit that converts the voltage Vc of the AC power supply 1 into a DC voltage. A smoothing capacitor (first capacitor) 7 is connected to the output of the converter 6. Inverters 8 and 31 and a DC / DC converter 33 serving as a DC power supply (first DC power supply) are connected between the two ends of the smoothing capacitor 7.

[0019] Inverter 8 converts the voltage Vdc of smoothing capacitor 7 into a three-phase AC voltage of a specified frequency for load drive. A drive motor (compressor motor) 20M for compressor 20 is connected to the output of inverter 8. Compressor 20 draws in gaseous refrigerant from its suction port, compresses it, and discharges the compressed gaseous refrigerant from its discharge port. One end of outdoor heat exchanger 22 is connected to the discharge port of compressor 20 via a four-way valve 21. Furthermore, one end of indoor heat exchanger 24 in indoor unit 60 is connected to the other end of outdoor heat exchanger 22 via an expansion valve 23 (which acts as a pressure reducer), and the other end of indoor heat exchanger 24 is connected to the suction port of compressor 20 via the aforementioned four-way valve 21. These piping connections constitute a heat pump refrigeration cycle. In cooling mode, as shown by the solid arrow, the refrigerant discharged from the compressor 20 flows to the outdoor heat exchanger 22 through the four-way valve 21. The refrigerant passing through the outdoor heat exchanger 22 then flows to the indoor heat exchanger 24 through the expansion valve 23. The refrigerant passing through the indoor heat exchanger 24 is then drawn into the compressor 20 through the four-way valve 21. The outdoor heat exchanger 22 functions as a condenser, and the indoor heat exchanger 24 functions as an evaporator. In heating mode, the flow path of the four-way valve 21 is switched, as shown by the dashed arrow. The refrigerant discharged from the compressor 20 flows to the indoor heat exchanger 24 through the four-way valve 21. The refrigerant passing through the indoor heat exchanger 24 then flows to the outdoor heat exchanger 22 through the expansion valve 23. The refrigerant passing through the outdoor heat exchanger 22 is then drawn into the compressor 20 through the four-way valve 21. The indoor heat exchanger 24 functions as a condenser, and the outdoor heat exchanger 22 functions as an evaporator.

[0020] Inverter 31 converts the voltage Vdc of the smoothing capacitor 7 into a three-phase AC voltage of a specified frequency for load driving. An outdoor fan drive motor (fan motor) 32M, which supplies outside air to the outdoor heat exchanger 22, is connected to the output of inverter 31. DC / DC converter (DC power supply) 33 converts the approximately 280V DC voltage Vdc of the smoothing capacitor 7 into a lower DC voltage of 5V or 12V suitable for the control components required for the operation of the outdoor unit 2. This DC / DC converter 33 is a self-oscillating DC / DC converter circuit that outputs a specified DC voltage by oscillating itself when the input voltage exceeds a specified value Vdcs, rather than based on an external signal input. A simple series converter can also be used instead of the self-oscillating DC / DC converter circuit.

[0021] An outdoor controller 40 and a sensor circuit 44 are connected to the output of the DC / DC converter 33. A relay 41 is connected via the collector-emitter junction of an NPN transistor 42 and a resistor 43. The base of the NPN transistor 42 is connected to the outdoor controller 40. When the outdoor controller 40 turns on the NPN transistor 42, the relay 41 is powered by the output voltage of the DC / DC converter 33. The sensor circuit 44 includes various sensors such as temperature sensors, pressure sensors, voltage sensors, and current sensors, as well as a zero-crossing detection circuit. The detection results of these sensors and the zero-crossing detection circuit are transmitted to the outdoor controller 40. The zero-crossing detection circuit detects the zero-crossing point of the power supply voltage Vc.

[0022] In the power line L1, a component for preventing inrush current, such as a self-heating resistor, i.e., a positive characteristic thermistor (also called a PTC thermistor), is inserted between the noise filter 4 and the converter 6. An isolation switch circuit 10 is connected between the positive characteristic thermistor 5 and the converter 6. Alternatively, as a component for preventing inrush current, a constant current component that only carries a certain value of current can be used instead of the positive characteristic thermistor 5.

[0023] The isolation switch circuit 10 includes: a light-emitting element, such as a photodiode 13a, inserted into the serial signal line L3 led out from the communication terminal 3c of the external connection terminal 3; a switch, such as a bidirectional thyristor (phototransistor) 11, inserted into the power line L1 between the positive characteristic thermistor 5 and the converter 6, forming a series circuit with the positive characteristic thermistor 5; and a bidirectional photothyristor (phototransistor) 13b, connected in parallel to the two ends of the bidirectional thyristor 11 via resistors 12 and 14 respectively, and turned on by receiving light from the photodiode 13a. The bidirectional thyristor 11 is triggered by the voltage generated between the photothyristor 13b and the resistor 14. The photodiode 13a and the bidirectional photothyristor 13b constitute an optocoupler 13. If the serial signals D1 and D2 (described later) flow through the serial signal line L3, the photodiode 13a emits light, and correspondingly, the bidirectional photothyristor 13b conducts. Based on the conduction of the bidirectional photothyristor 13b, the bidirectional thyristor 11 conducts. In addition to the current path formed by the conduction of the bidirectional photothyristor 13b, a current path is also formed by the conduction of the bidirectional thyristor 11, thus ensuring sufficient current capacity in the power line L1. That is, sufficient current capacity in the power line L1 cannot be ensured solely by a common photothyristor element, the bidirectional photothyristor 13b, which does not have a large rated voltage. Therefore, in the isolation switching circuit 10, a two-stage switching circuit is constructed that connects the bidirectional photothyristor 13b in parallel with the bidirectional thyristor 11 and triggers the bidirectional thyristor 11 through the output of the bidirectional photothyristor 13b. However, if a photothyristor element with a high rated voltage can be used as a bidirectional photothyristor 13b, then the bidirectional thyristor 11 of the second stage can also be omitted.

[0024] A bypass line 9 is connected in parallel to the series circuit of the positive characteristic thermistor 5 and thyristor 11 in power line L1. A normally open switch, such as a normally open relay contact 41a, is inserted into the bypass line 9. Relay contact 41a is the normally open contact of relay 41.

[0025] A serial communication circuit (first serial communication circuit) 50 is connected between the serial signal line L3, which is led out from the communication terminal 3c, and the power lines L1 and L2, via the aforementioned photodiode 13a. The serial communication circuit 50 has a power path 50x from the serial signal line L3 to the power line L1, a transmitting unit 51 inserted in the power path 50x, a power path 50y from the serial signal line L3 to the power line L2, and a receiving unit 52 inserted in the power path 50y. The transmitting unit 51 is an optocoupler (photothyristor coupler) composed of a photodiode 51a connected to the outdoor controller 40 and a photothyristor 51b inserted in the power path 50x. According to the instruction from the outdoor controller 40, it generates a serial signal (first serial signal) D1 that is synchronized with the negative half-wave voltage of the AC power supply 1, and transmits the generated serial signal D1 to the indoor unit 60 through the serial signal line L3 and the serial signal line C3. The receiving unit 52 is an optocoupler (optotransistor coupler) consisting of a photodiode 52a inserted in the power path 50y and a phototransistor 52b connected to the outdoor controller 40. It receives the serial signal (second serial signal) D2, which is transmitted from the indoor unit 60 in sync with the positive half-wave voltage of the AC power supply 1, via serial signal line C3 and serial signal line L3.

[0026] The outdoor controller 40 consists of a microcomputer and its peripheral circuits. It operates by the output voltage of the DC / DC converter 33 based on the voltage of the smoothing capacitor 7, and executes the next first control, second control, and third control.

[0027] In the first control, after a predetermined time from the start of the operation based on the output voltage of the DC / DC converter 33, the outdoor controller 40 turns on the NPN transistor 42 to apply force to the relay 41, thereby closing the relay contact 41a.

[0028] In the second control, the outdoor controller 40, upon the start of operation based on the output voltage of the DC / DC converter 33, performs serial communication (data transmission and reception) with the indoor unit 60 via the serial communication circuit 50. Based on the content of this serial communication and the detection results of various sensors in the sensor circuit 44, it controls the flow path of the four-way valve 21 and the switching of the inverters 8 and 31.

[0029] In the third control, when the outdoor controller 40 receives an instruction to stop operation from the indoor unit 60 via the aforementioned serial communication for control, and the operation of the outdoor unit 2 becomes unnecessary, it turns off the NPN transistor 42 and does not apply force to the relay 41, thereby opening the relay contact 41a. As a result, the output DC voltage Vdc of the capacitor 7 decreases, and ultimately the operation of the DC / DC converter 33 stops, and the outdoor controller 40 itself stops.

[0030] In outdoor unit 2, the various electrical components that consume power are located downstream of converter 6. Therefore, by not applying force to relay 41, the power consumption of outdoor unit 2 becomes "0", which can reduce the standby power of the air conditioner.

[0031] [Structure of Indoor Unit 60] Power lines L4 and L5 are led out from the power terminals 61a and 61b of the external connection terminal 61. A converter (second converter) 63 is connected to these power lines L4 and L5 via a noise filter 62. The converter 63 is, for example, a diode bridge rectifier circuit that converts the voltage Vc of the AC power supply 1 into a DC voltage. A smoothing capacitor (second capacitor) 64 is connected to the output of the converter 63, and an inverter 65 is connected to the smoothing capacitor 64. The inverter 65 converts the voltage of the smoothing capacitor 64 into an AC voltage of a specified frequency for driving the drive motor (fan motor) 66 of the indoor fan. Furthermore, since there are no electrical components in the indoor unit 60 that consume large amounts of power, a small-capacity capacitor is used as the smoothing capacitor 64. Because the smoothing capacitor 64 has a small capacitance, structures for preventing inrush current, such as a positive characteristic thermistor 5, are not provided in the indoor unit 60.

[0032] A DC / DC converter 67, serving as a DC power supply (second DC power supply), is connected to the smoothing capacitor 64. The DC / DC converter 67 converts the voltage of the smoothing capacitor 64 into a DC voltage required for the operation of the indoor unit 60 and outputs it. An indoor controller 70, a sensor / louver circuit 71, and a light-receiving unit 72 are connected to the output of the DC / DC converter 67. Additionally, an inverter 65 is connected to the indoor controller 70, and the outdoor controller 70 instructs the inverter 65 to change its output frequency, thereby altering the speed of the indoor fan. The sensor / louver circuit 71 includes various sensors such as a temperature sensor, a human sensor, and a current sensor, a zero-crossing detection circuit, and a louver motor for airflow adjustment. It notifies the indoor controller 70 of the detection results from the various sensors and the zero-crossing detection circuit, and drives the louver motor according to instructions from the indoor controller 70. The light-receiving unit 72 receives an infrared light signal for operation from a remote control and supplies this light signal to the indoor controller 70.

[0033] A serial signal line L6 is led out from the communication terminal 61c of the external connection terminal 61. A serial communication circuit (second serial communication circuit) 80 is connected between the serial signal line L6 and the power lines L4 and L5. The serial communication circuit 80 has a power path 80x from the power line L4 to the serial signal line L6, a transmitting unit 81 inserted in the power path 80x, a power path 80y from the power line L5 to the serial signal line L6, and a receiving unit 82 inserted in the power path 80y. The transmitting unit 81 is an optocoupler (photothyristor coupler) composed of a photodiode 81a connected to the indoor controller 70 and a photothyristor 81b inserted in the power path 80x. According to the instructions from the indoor controller 70, it generates a serial signal (second serial signal) D2 that is synchronized with the positive half-wave voltage of the AC power supply 1, and transmits the generated serial signal D2 to the outdoor unit 2 through the serial signal line L6 and the serial signal line C3. The receiving unit 82 is an optocoupler (optotransistor coupler) consisting of a photodiode 82a inserted in the power path 80y and a phototransistor 82b connected to the indoor controller 70. It receives the serial signal D1 transmitted from the outdoor unit 2 in sync with the negative half-wave voltage of the AC power supply 1 via serial signal lines C3 and L6.

[0034] The indoor controller 70, like the outdoor controller 40, consists of a programmed microcomputer and its peripheral circuitry. It operates based on the output voltage of the DC / DC converter 67, which is based on the voltage of the smoothing capacitor 64, and executes the next 11th / 12th control / 13th control.

[0035] In the 11th control, when the light receiving unit 72 receives infrared light or the like, indicating the start of operation from the remote control, and the operation of the outdoor unit 2 is required, the indoor controller 70 continuously sends out the serial signal D2 from the serial communication circuit 80.

[0036] In the 12th control, after the continuous serial signal D2 is sent out, the indoor controller 70 performs serial communication (data transmission and reception) with the outdoor unit 2 via the serial communication circuit 80. Based on the content of the serial communication, the light receiving state of the light receiving unit 72, and the detection results of various sensors in the sensor / louver circuit 71, the controller controls the operation of the fan motor 65 (the operation of the inverter 65) and the operation of the louver motor in the sensor / louver circuit 71.

[0037] In the 13th control, when the indoor controller 70 receives infrared light signals such as the operation stop indication sent from the remote control operator in the light receiving unit 72 and the operation of the air conditioner is no longer needed, it sends a serial signal D2 from the serial communication circuit 80 to indicate the operation stop.

[0038] [Control of Indoor Controller 70] Reference Figure 2 Flowcharts and Figure 3 The timing diagram is used to illustrate the control of the indoor controller 70. Hereinafter, the steps S1, S2... in the flowchart will be referred to as S1, S2...

[0039] When AC power 1 is switched on, the power supply voltage Vc is applied to converter 63 via power terminals 61a and 61b, filter 62, and power lines L4 and L5. The output voltage of converter 63 is applied to smoothing capacitor 64. When the voltage of smoothing capacitor 64 rises and exceeds a predetermined value, DC / DC converter 67 starts operating (is switched on). Through the output voltage of DC / DC converter 67, indoor controller 70 starts operating (is switched on).

[0040] After the operation begins, the indoor controller 70 determines whether the operation of the outdoor unit 2 is required (S1). If the light receiving unit 72 does not receive the infrared light signal indicating the start of operation sent from the remote control, the indoor controller 70 returns to the above-mentioned S1 to continue monitoring if it determines that the operation of the outdoor unit 2 is not required (S1 no).

[0041] When the light-receiving unit 72 receives an infrared light signal indicating the start of operation, the indoor controller 70, upon determining that operation of the outdoor unit 2 is required (S1), proceeds as follows: Figure 3 As shown, a serial signal D2 synchronized with the positive half-wave voltage of the power supply voltage Vc is continuously sent from the serial communication circuit 80 (S2), and the passage of a certain time tx is monitored from the start of this sending (S3). During the period before the certain time tx has passed (S3, if not), the indoor controller 70 returns to the above S2 and continues to continuously send the serial signal D2 (S2). Here, each serial signal D2 refers to the signal flowing on the "H" signal, i.e., the current serial signal line C3.

[0042] After a certain time tx (S3 is yes), the indoor controller 70 stops the continuous transmission of the serial signal D2 and performs serial communication (data transmission and reception) for control with the outdoor unit 2 via the serial communication circuit 80 (S4). During this execution, the indoor controller 70 monitors whether the light-receiving unit 72 receives the infrared light signal indicating a stop operation sent from the remote control (S5). If the light-receiving unit 72 does not receive the infrared light signal indicating a stop operation (S5 is no), the indoor controller 70 returns to S4 to continue the serial communication for control (S4). If the light-receiving unit 72 receives the infrared light signal indicating a stop operation (S5 is yes), the indoor controller 70 indicates to the outdoor unit 2 that operation has stopped via serial communication (S6). Afterwards, the indoor controller 70 stops the transmission of serial communication, returns to S1, and monitors whether operation of the outdoor unit 2 is required (S1).

[0043] [Control of outdoor controller 40] Reference Figure 3 Timing diagram and Figure 4 The flowchart illustrates the control of the outdoor controller 40.

[0044] When AC power 1 is switched on, the power supply voltage Vc is applied to power lines L1 and L2 via power terminals 3a and 3b and filter 4. At this moment, relay contact 41a is open, and the bidirectional thyristor 11 and bidirectional photothyristor 13b of the isolation switch circuit 10 are both turned off, so the power supply voltage Vc of power lines L1 and L2 is not applied to converter 6. No signal flows through the serial communication line until the indoor unit 60 determines that the operation of the outdoor unit 2 is required. When the indoor unit 60 determines that the operation of the outdoor unit 2 is required ( Figure 3 At time t0, the serial communication circuit 80 of the indoor unit 60 continuously sends out serial signals D2. The receiving unit 52 of the serial communication circuit 50 receives each serial signal D2 and supplies the received signal to the outdoor controller 40. However, at this time, the outdoor controller 40 does not receive the operating voltage from the DC / DC converter 33, and is therefore in an off-state.

[0045] exist Figure 3 In the timing diagram shown, during the period when the voltage of each serial signal D2 sent from indoor unit 60 is above the specified value indicated by the dashed line, the photodiode 13a of optocoupler 13 emits light. When photodiode 13a emits light, bidirectional photothyristor 13b turns on, and according to its turning on, bidirectional thyristor 11 is triggered to turn on. The turned-on bidirectional thyristor 11 turns off at a timing when the positive half-wave voltage of the power supply voltage Vc drops to zero.

[0046] During the period when the bidirectional thyristor 11 is turned on, the power supply voltage Vc between power lines L1 and L2 is applied to the converter 6 through the positive characteristic thermistor 5. That is, a voltage Vt with a waveform that rises corresponding to the turn-on of the bidirectional thyristor 11 and falls corresponding to the turn-off of the bidirectional thyristor 11 is applied to the converter 6.

[0047] Furthermore, in this embodiment, a serial signal D2 synchronized with the positive half-wave voltage of the power supply voltage Vc is continuously sent from indoor unit 60 to indoor unit 2. This serial signal D2 turns on the bidirectional photothyristor 13b, and the conduction of the bidirectional photothyristor 13b triggers the bidirectional thyristor 11. Therefore, both the bidirectional photothyristor 13b and the bidirectional thyristor 11 conduct only during the positive level of the power supply voltage Vc and do not conduct during the negative level. Considering that the bidirectional photothyristor 13b and the bidirectional thyristor 11 conduct only during the positive level of the power supply voltage Vc, it is also possible to replace thyristors and photothyristors that only flow current in one direction with bidirectional photothyristors 13b and bidirectional thyristor 11.

[0048] When AC power 1 is switched on, if the power supply voltage Vc is applied to converter 6 at its original level, a large inrush current will flow from AC power 1 to converter 6 and smoothing capacitor 7. However, when AC power 1 is switched on, the positive characteristic thermistor 5 is located on the power line L1 between AC power 1 and converter 6, therefore, a voltage Vt lower than the power supply voltage Vc is applied to converter 6. Therefore, a large inrush current will not flow from AC power 1 towards converter 6 and smoothing capacitor 7.

[0049] The voltage Vt applied to converter 6 is rectified by converter 6 and then applied to smoothing capacitor 7. As a result, the voltage Vdc of smoothing capacitor 7 gradually increases.

[0050] When the voltage Vdc of the smoothing capacitor 7 rises above the specified value Vdcs, the DC / DC converter 33 starts operating (turns on) and outputs the specified DC voltage. The output voltage of the DC / DC converter 33 is applied to the outdoor controller 40 and the sensor circuit 44. As a result, the outdoor controller 40 and the sensor circuit 44 start operating (turn on).

[0051] Furthermore, since the bidirectional photothyristor 13b is turned on by a serial signal D2 synchronized with the positive half-wave voltage of the power supply voltage Vc, and the bidirectional photothyristor 11 is triggered by the turn-on of the bidirectional photothyristor 13b, the bidirectional photothyristor 11 can be turned on for as long as possible, approximately half a cycle of the power supply voltage Vc. Because the on-time of the bidirectional photothyristor 11 can be extended as much as possible, the voltage Vdc of the smoothing capacitor 7 can be increased earlier, thereby accelerating the start of operation of the DC / DC converter 33 and the outdoor controller 40.

[0052] After the operation begins, the outdoor controller 40 checks whether it has received the continuous serial signal D2 from the receiving unit 52 of the serial communication circuit 50 at a certain time t1 from the start of the operation (S11). If the continuous serial signal D2 is not received (S11 no), the outdoor controller 40 returns to S11 and repeatedly checks the received signal.

[0053] Upon receiving the continuous serial signal D2 (as in S11), the outdoor controller 40, having determined that it is no longer concerned about inrush current, turns on the NPN transistor 42 to apply force (close) the relay 41 (S12), thereby closing the relay contact 41a. When the relay contact 41a is closed, the bypass line 9 is turned on, and the power supply voltage Vc of the power lines L1 and L2 is applied to the converter 6 at the same level.

[0054] While maintaining the current flowing through the positive characteristic thermistor 5 as before, the temperature of the positive characteristic thermistor 5 continues to rise and the resistance value increases accordingly, which will generate unnecessary power consumption or reduce the input current to the converter 6 so that the inverters 8 and 31 cannot be driven. Therefore, by turning on the bypass line 9, the power supply voltage Vc is directly supplied to the converter 6.

[0055] Furthermore, when the relay 41 is subjected to force, the voltage between the two ends of the insulating switch 10 becomes the same potential, therefore, as Figure 3 As shown, even if photodiode 13a emits light due to the subsequent generation of serial signal D2, bidirectional photothyristor 13b remains off, and bidirectional thyristor 11 does not turn on.

[0056] On the other hand, after the relay 41 applies force, in Figure 3 At time t2, the outdoor controller 40 performs serial communication (data transmission and reception) with the indoor unit 60 via the serial communication circuit 50 for control purposes (S13). Based on the content of the serial communication and the detection results of various sensors in the sensor circuit 44, it controls the flow path of the four-way valve 21 and the switching of the inverters 8 and 31.

[0057] Upon receiving an instruction to stop operation from the indoor unit 60 via serial communication for control (S14), the outdoor controller 40, determining that operation of the outdoor unit 2 is not required, turns off the NPN transistor 42 without applying force (disconnecting) to the relay 41 (S15), thereby opening the relay contact 41a. When the relay contact 41a is open, the bypass line 9 is cut off.

[0058] When the bypass line 9 is disconnected, the series circuit of the positive characteristic thermistor 5 and the resistors 12, 13b, and 14 of the isolation switch circuit 10 is connected to the power line L1 between the AC power supply 1 and the converter 6. At this moment, serial communication with the indoor unit 60 ends and the serial signal D2 is not received. Therefore, the 11 and 13b of the isolation switch circuit 10 remain in the off state, and the power supply voltage Vc of the power lines L1 and L2 is not applied to the converter 6. Subsequently, with the power consumption in the outdoor controller 40 and various sensor circuits, the voltage Vdc of the smoothing capacitor 7 gradually decreases, and after tens of seconds, it drops below the specified value Vdcs. The DC / DC converter 33 stops operating and does not supply power to the outdoor controller 40, and the outdoor controller 40 also stops operating.

[0059] Thus, in standby mode where outdoor unit 2 is not required to operate, even when AC power 1 is connected, power supply from AC power 1 to the internal devices of outdoor unit 2 is prohibited. Therefore, no standby power is generated in outdoor unit 2, improving the energy-saving effect of the air conditioner.

[0060] [2] The second embodiment will be described with reference to the accompanying drawings.

[0061] like Figure 5 As shown, the position between the positive characteristic thermistor 5 and the converter 6 in the power line L1 is replaced by the insulation switch circuit 10 of the first embodiment, and the insulation switch circuit 80 is connected via resistor 91.

[0062] The isolation switch circuit 80 includes: a switch, such as a series circuit of a pair of MOSFETs 81 and 82, inserted between a resistor 91 and the converter 6 in the power supply line L1, forming a series circuit together with a positive characteristic thermistor 5 and the resistor 91; and a light-emitting element, such as a photodiode 83, inserted into the serial signal line L3 led out from the communication terminal 3c of the external connection terminal 3. MOSFETs 81 and 82 each have parasitic diodes 81a and 81b, respectively, which operate in response to the light emission of the photodiode 83. That is, when serial signals D1 and D2 flow through the serial signal line L3, the photodiode 83 emits light, and during the period when the photodiode 83 emits light, MOSFETs 81 and 82 are turned on. When MOSFETs 81 and 82 are turned on, the positive half-wave voltage of the power supply voltage Vc is applied to the converter 6 through the body of MOSFET 81 and the parasitic diode 82a of MOSFET 82, and the negative half-wave voltage of the power supply voltage Vc is applied to the converter 6 through the body of MOSFET 82 and the parasitic diode 81a of MOSFET 81.

[0063] The other structures, controls, and effects are the same as in the first embodiment. Therefore, the description of its structure, controls, and effects is omitted.

[0064] [3] Variations of the first and second embodiments In the above embodiments, a structure is adopted in which serial signal D1 is synchronized with the negative half-wave voltage of AC power supply 1, and serial signal D2 is synchronized with the positive half-wave voltage of AC power supply 1. However, a structure can also be adopted in which serial signal D1 is synchronized with the positive half-wave voltage of AC power supply 1, and serial signal D2 is synchronized with the negative half-wave voltage of AC power supply 1. In short, as long as serial signal D1 is synchronized with either the positive or negative half-wave voltage, and serial signal D2 is synchronized with the half-wave voltage of the side that is different from that of serial signal D1, it is acceptable. Furthermore, a circuit can be configured that enables both indoor controller 70 and outdoor controller 40 to transmit and receive serial signals in both positive and negative directions, and to transmit and receive signals between indoor controller 70 and outdoor controller 40 in a time-division manner.

[0065] In the above embodiments, relay contact 41a is used as the switch inserted into bypass line 9, but other switches such as semiconductor switching elements can also be used as long as they have the same function.

[0066] In the above embodiments, the case of using a diode bridge rectifier circuit as converter 6 and 63 has been described as an example, but converters for reducing higher harmonics or boost converters can also be used.

[0067] Furthermore, the above-described embodiments and their variations are merely illustrative examples and are not intended to limit the scope of the invention. These new embodiments and their variations can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention and its equivalents as described in the claims.

[0068] Explanation of reference numerals in the attached figures 1…AC power supply, 2…outdoor unit, 3…external connection terminal, 3a, 3b…power terminal, 3c…communication terminal, L1, L2…power line, L3…serial signal line, C1, C2…power cable, C3…serial signal line, 5…positive characteristic thermistor (component for surge current prevention), 6…converter, 7…smoothing capacitor, 8…inverter, 9…bypass line, 10…isolated switch circuit, 11…tri-directional thyristor, 13…optocoupler, 13a…photodiode, 13b…tri-directional thyristor, 20M…compressor motor, 31…inverter, 32M…fan motor, 33… DC / DC converter (DC power supply), 40…outdoor controller, 41…relay, 41a…relay contact (switch), 50…serial communication circuit (first serial communication circuit), 51…transmitter, 52…receiver, 60…indoor unit, 61…external connection terminal, 61a, 61b…power terminal, 61c…communication terminal, 65…inverter, 67…DC / DC converter (DC power supply), 70…indoor controller, 80…serial communication circuit (second serial communication circuit), 81…transmitter, 82…receiver.

Claims

1. An air conditioner comprising an outdoor unit and an indoor unit, wherein the outdoor unit and the indoor unit are interconnected via a serial signal line for data transmission, characterized in that... The outdoor unit includes: A converter that converts AC power voltage to DC voltage; A capacitor connected to the output terminal of the converter; A component for preventing inrush current is inserted into the power line between the AC power source and the converter; A light-emitting element is disposed on the serial signal line and emits light according to the serial signal passing through the serial signal line; A switch is inserted into the power line and forms a series circuit with the inrush current prevention element. It is turned on by the light emission of the light-emitting element, thereby applying the voltage of the AC power supply to the converter through the inrush current prevention element. A normally open switch is connected in parallel with the series circuit of the inrush current prevention element and the switch, and the voltage of the AC power supply is directly supplied to the converter by closing the normally open switch. The receiving unit receives, via the serial signal line, a serial communication signal transmitted from the indoor unit in sync with the half-wave voltage of the AC power supply. as well as The outdoor controller operates based on the voltage of the capacitor to which the output voltage of the converter is applied, closing the switch after a predetermined time from the start of operation, and opening the switch when the operation of the outdoor unit is not required. The switch's activation is independent of the outdoor controller; rather, before the outdoor controller begins operation, the switch's activation is controlled solely by the serial signal sent from the indoor unit. The indoor unit includes: The transmitting unit transmits the serial signal to the outdoor unit via the serial signal line; as well as When the outdoor unit needs to be operated, the indoor controller continuously sends a serial signal from the transmitting unit to the serial signal line to turn on the switch, causing the light-emitting element to emit light. After the switch is turned on according to the serial signal, and the capacitor is charged to a voltage above the specified voltage, the outdoor controller begins to operate.

2. The air conditioner according to claim 1, characterized in that, The light-emitting element is a photodiode. The switch is a thyristor.

3. The air conditioner according to claim 2, characterized in that, The switch is an insulated switch circuit, which includes the thyristor and a photothyristor. The photothyristor is connected in parallel with the thyristor and is turned on by receiving light from the photodiode. The insulated switch circuit triggers the thyristor in response to the conduction of the photothyristor.

4. The air conditioner according to claim 1, characterized in that, The light-emitting element is a photodiode. The switch is a series circuit of a pair of MOSFETs that operates in response to the light emitted by the photodiode.

5. The air conditioner according to claim 1, characterized in that, The transmitting unit of the indoor unit transmits a second serial signal, synchronized with the half-wave voltage of the AC power supply, to the outdoor unit via the serial signal line for serial communication. The receiving unit of the outdoor unit receives the second serial signal transmitted from the transmitting unit of the indoor unit via the serial signal line. The outdoor unit also includes a transmitter that transmits a first serial signal, synchronized with the half-wave voltage of the AC power supply, to the indoor unit via the serial signal line for serial communication. The indoor unit further includes a receiving unit that receives the first serial signal transmitted from the transmitting unit of the outdoor unit via the serial signal line. The first serial signal is synchronized with the half-wave voltage on the positive or negative side of the AC power supply. The second serial signal is synchronized with a half-wave voltage on a different side of the following half-wave voltage, which is the half-wave voltage on the side synchronized by the first serial signal.

6. The air conditioner according to claim 1, characterized in that, The outdoor unit also includes: An inverter that converts the voltage of the capacitor into an AC voltage for load driving; and A DC power supply, connected to the capacitor, outputs the DC voltage required for the operation of the outdoor unit, including the operation of the outdoor controller, when the voltage of the capacitor is above a specified value.

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