JP6021461B2 - Outdoor unit for air conditioner and control method thereof - Google Patents

Description

  The present invention relates to an outdoor unit of an air conditioner and a control method thereof.

  Depending on the application of the air conditioner, it may be used in an extremely cold environment such as in a cold region or a cold warehouse. In such a severe environment, the control microcomputer (Hereinafter abbreviated as “microcomputer”) and other electronic circuits may malfunction.

  In electronic devices that may be used in extremely low temperature environments such as in-vehicle hard disk drives, heaters and other warming devices are used to prevent malfunctions of the microcomputer and to ensure normal startup and stable operation. The microcomputer is raised to an appropriate temperature by the up means (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2004-355738

  On the other hand, in an air conditioner that performs variable speed control of a compressor motor with an inverter, the stable operation of all electronic circuits including the inverter cannot be guaranteed just by raising the microcomputer to an appropriate temperature, and further improvements are required. It was.

  The present invention has been made to solve the above-described problems, and an object thereof is to stably operate an electronic circuit including a microcomputer and an inverter even in an extremely low temperature environment.

An outdoor unit of an air conditioner according to the present invention includes an air conditioner including a control board on which a control microcomputer and a power supply circuit are mounted, and an inverter board on which a semiconductor module that constitutes an inverter for driving a compressor is mounted. Outdoor unit,
After the power supply of the air conditioner is turned on, a current is supplied from the power supply circuit to a heating element mounted in the vicinity of the microcomputer of the control board to heat the microcomputer, and the temperature of the microcomputer is set to a predetermined first temperature. Raise the temperature to
When the temperature of the microcomputer exceeds the first temperature, power is supplied from the power supply circuit to the microcomputer to be operable.
Under the control of the microcomputer, ON and OFF of the semiconductor module are alternately repeated to raise the temperature of the semiconductor module to a predetermined second temperature,
When the temperature of the semiconductor module exceeds the second temperature, it is determined that the control of the semiconductor module can be shifted to the control of the normal operation.

  The outdoor unit of the air conditioner according to the present invention heats the vicinity of the microcomputer on the board on which the microcomputer is mounted to a first temperature at which the microcomputer operates stably, and further includes an inverter for driving the compressor mounted on the inverter board. Since the transition to the normal operation is performed after the semiconductor module constituting the temperature reaches or exceeds the second temperature at which the semiconductor module operates stably, the outdoor unit can be reliably and stably operated even in an extremely low temperature environment. it can.

It is the front view (a) and side view (b) of the outdoor unit of the air conditioning apparatus in Embodiment 1 of this invention. FIG. 3 is a diagram showing an arrangement of components on a control board in the first embodiment. FIG. 3 is a diagram showing an arrangement of parts of an inverter board in the first embodiment. 3 is a flowchart showing a control flow when the outdoor unit of the air-conditioning apparatus according to Embodiment 1 is started. 6 is a graph showing a change in temperature in the controller in the first embodiment. FIG. 10 is a diagram illustrating an arrangement of components of a control board in the second embodiment.

Embodiment 1 FIG.
1A and 1B show a schematic configuration of an outdoor unit of an air-conditioning apparatus according to Embodiment 1 of the present invention. FIG. 1A is a front view and FIG. 1B is a side view.

  The present invention is premised on being applied to an air conditioner that performs variable speed control of a compressor motor by an inverter. A controller 2 is installed at the upper part of the outer surface of the outdoor unit 1 of the air conditioner, and a compressor 3 for compressing the refrigerant is installed at the lower part of the outdoor unit 1.

  The controller 2 controls the operation of the outdoor unit 1 including the compressor 3, and includes a control board 4 on which a microcomputer is mounted and an inverter board 5 on which a semiconductor module that constitutes an inverter for driving the compressor 3 is mounted. It is housed in a sheet metal box 6. The outer surface of the sheet metal box 6 is covered with a sheet metal cover (not shown), and the state of the substrate and the like is confirmed by removing the cover during maintenance.

  FIG. 2 shows the arrangement of components on the control board 4. The control board 4 is mounted with a microcomputer 41 and a power supply circuit 42 that supplies power to the microcomputer 41 and the inverter board 5. A program for controlling the operation of the air conditioner is stored in the memory of the microcomputer 41. The microcomputer 41 controls the operation of the outdoor unit 1 by reading this program and executing it by the CPU.

  In the vicinity of the microcomputer 41 of the control board 4, a bimetal switch 43 and a heater 44 are mounted. The bimetal switch 43 is connected between the heater 44 and the microcomputer 41, and when the temperature of the bimetal switch 43 reaches a predetermined first temperature, the switch is switched from closed (ON) to open (OFF). When the bimetal switch 43 is turned on, the power of the power supply circuit 42 is supplied to the heater 44. On the other hand, when the bimetal switch 43 is turned off, the power of the power supply circuit 42 is supplied to the microcomputer 41. A heater 44, which is a kind of heating element, heats the microcomputer 41, and generates heat due to the current supplied from the power supply circuit.

  FIG. 3 shows the arrangement of components on the inverter board 5. The inverter board 5 includes a semiconductor that constitutes an inverter for driving the compressor 3, which is composed of an IGBT (Insulated Gate Bipolar Transistor) or a diode that is a switching element. A module 51 and a control IC 52 for controlling the operation of the semiconductor module 51 are mounted. The semiconductor module 51 is configured such that the output frequency changes according to the necessary refrigerant circulation amount.

  The semiconductor module 51 has a built-in temperature sensor 53, and a signal detected by the temperature sensor 53 is input to the microcomputer 41. When the detected value of the temperature sensor 53 reaches a predetermined second temperature, the microcomputer 41 determines that the control of the semiconductor module can be shifted to normal operation.

  Next, the operation of the outdoor unit 1 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart for explaining the operation at the time of starting the outdoor unit 1, and FIG. 5 is a graph showing a temporal change in the temperature in the controller 2.

  In the present invention, after the microcomputer 41 is heated using the heater 44 and reaches a temperature at which the microcomputer 41 operates stably, the semiconductor module 51 is warmed by so-called restraint energization, and the temperature in the controller 2 is changed to the microcomputer 41 and The temperature is raised to a temperature at which all electronic circuits including the semiconductor module 51 operate stably.

  Here, the restraint energization is performed to warm the motor winding of the compressor 3, and the semiconductor module 51 is repeatedly turned on and off at a time interval that does not cause the semiconductor module 51 to malfunction. The semiconductor module 51 self-heats by this switching operation and rises to a temperature at which the semiconductor module 51 operates stably.

  Usually, the first temperature at which the microcomputer 41 operates stably is lower than the second temperature at which the semiconductor module 51 operates stably. The temperature at which electronic components other than semiconductors (including microcomputers) used in the circuit operate stably is lower than the first temperature at which the microcomputer 41 operates stably, and is stable even at about −30 ° C. Operate.

  As shown in FIG. 5, immediately after the power is turned on, that is, in a state where power is not supplied from the power supply circuit 42 to each substrate, the temperature in the controller 2 is T0.

  The user turns on the power and starts operation (step S1). In this state, since the bimetal switch 43 is closed (ON), power is supplied from the power supply circuit 42 to the heater 44, and a current flows through the heater 44 to heat it (step S2). Since the microcomputer 41 and the bimetal switch 43 are installed in the vicinity of the heater 44, they are heated to almost the same temperature by the heater 44. At this time, no power is supplied to the microcomputer 41 from the power supply circuit 42.

  As described above, the bimetal switch 43 is set in advance to be closed (ON) below the first temperature T1 at which the microcomputer 41 may malfunction, and to open (OFF) above T1. Until the temperature of the microcomputer 41 and the bimetal switch 43 reaches T1 (No in step S3), the heater 44 continues to be heated.

  When the temperature of the microcomputer 41, that is, the temperature of the bimetal switch 43 exceeds T1 (Yes in step S3), the bimetal switch 43 is turned off, power supply from the power supply circuit 42 to the heater 44 is stopped, and power supply to the microcomputer 41 is performed. Is started to enter an operating state (step S4).

  Thereafter, until the temperature of the semiconductor module 51 detected by the temperature sensor 53 exceeds T2 (Yes in step S6), the normal operation is not performed, and the restraint energization of the semiconductor module 51 is performed according to the control of the microcomputer 41 (step S4). . The semiconductor module 51 self-heats by this switching operation, and the temperature of the semiconductor module 51 rises.

  If the temperature of the semiconductor module 51 detected by the temperature sensor 53 exceeds T2 (Yes in step S6), the microcomputer 41 can determine that the semiconductor module 51 has reached a stable operating temperature and shift to normal operation control. Is determined (step S7).

  As described above, after the microcomputer 41 exceeds the predetermined first temperature T1 due to the heat generated by the heater 44 mounted on the control board 4, the semiconductor module 51 is repeatedly turned on and off. By heating and starting the normal operation after the semiconductor module 51 exceeds the predetermined second temperature T2, the controller 2 including the microcomputer 41 and the semiconductor module 51 can be reliably connected even in an extremely low temperature environment. It can be operated stably.

Embodiment 2. FIG.
In the first embodiment described above, the heater 44 is mounted on the control board 4 and the vicinity of the microcomputer 41 is heated. However, in the present embodiment, a heating circuit, that is, a circuit including a part that generates heat is placed near the microcomputer 41. By arranging, the temperature of the microcomputer 41 is raised until it exceeds a predetermined first temperature T1.

  FIG. 6 is a diagram showing the configuration of the control board 4A in the second embodiment. In the present embodiment, a circuit 45 including components that generate heat such as a regulator and a temperature sensor 46 that detects the temperature of the microcomputer 41 are installed in the vicinity of the microcomputer 41 mounted on the control board 4A.

  The operation of the controller 2 in the present embodiment is basically the same as the operation of the controller 2 in the first embodiment described with reference to FIGS. 4 and 5. After powering on the air conditioner, the temperature of the microcomputer 41 is detected using the temperature sensor 46.

  If the microcomputer 41 exceeds a predetermined first temperature T1 due to heat generated by the heat generation circuit 45 installed in the vicinity of the microcomputer 41, the temperature of the semiconductor module 51 is then confirmed by the temperature sensor 53. If the temperature of the semiconductor module 51 is lower than the predetermined second temperature T2, the semiconductor module 51 is heated only by restraint energization, that is, by a simple ON / OFF operation.

  When the temperature of the semiconductor module 51 exceeds the second temperature T2 at which the semiconductor module 51 operates stably due to the heating of the semiconductor module 51, the ON / OFF operation of the semiconductor module 51 is stopped and the normal operation is started.

  As described above, in the present embodiment, the vicinity of the microcomputer is heated using the heat generated by the heat generating circuit that is mounted according to the original need. In addition, the controller 2 can be reliably and stably operated even in an environment where the temperature is low.

DESCRIPTION OF SYMBOLS 1 Outdoor unit 2 Controller 3 Compressor 4 Control board 5 Inverter board 6 Box 41 Microcomputer 42 Power supply circuit 43 Bimetal switch 44 Heater 45 Heat generation circuit 46, 53 Temperature sensor 51 Semiconductor module 52 Control IC

Claims (6)

An air conditioner outdoor unit comprising a control board on which a control microcomputer and a power supply circuit are mounted, and an inverter board on which a semiconductor module constituting a compressor driving inverter is mounted,
After the power supply of the air conditioner is turned on, a current is supplied from the power supply circuit to a heating element mounted in the vicinity of the microcomputer of the control board to heat the microcomputer, and the temperature of the microcomputer is set to a predetermined first temperature. Raise the temperature to
When the temperature of the microcomputer exceeds the first temperature, power is supplied from the power supply circuit to the microcomputer to be operable.
Under the control of the microcomputer, ON and OFF of the semiconductor module are alternately repeated to raise the temperature of the semiconductor module to a predetermined second temperature,
An outdoor unit of an air conditioner configured to determine that control of the semiconductor module can be shifted to control of normal operation when the temperature of the semiconductor module exceeds the second temperature. The temperature of the microcomputer is detected using a bimetal switch mounted in the vicinity of the microcomputer of the control board,
The bimetal switch, Ri temperature of the microcomputer automatically turn from ON to OFF exceeds the first temperature, power to the microcomputer from the power supply circuit is characterized in that a state is supplied, claims The outdoor unit of the air conditioning apparatus described in 1. The outdoor unit of the air conditioner according to claim 1 or 2, wherein the temperature of the semiconductor module is detected using a temperature sensor built in the semiconductor module. The heating element according to any one of claims 1 to 3, wherein the heating element is either a heater or a circuit including a component that generates heat among circuits constituting a controller including the control board and the inverter board . The outdoor unit of the air conditioning apparatus in any one. A control method for an outdoor unit of an air conditioner comprising a control board on which a control microcomputer and a power supply circuit are mounted, and an inverter board on which a semiconductor module constituting a compressor drive inverter is mounted,
After the operation of the air conditioner is turned on, a current is supplied from the power supply circuit to a heating element mounted in the vicinity of the microcomputer of the control board to heat it, thereby setting the temperature of the microcomputer to a predetermined value. Raising the temperature to 1;
When the temperature of the microcomputer exceeds the first temperature, supplying power from the power supply circuit to the microcomputer to be operable;
Step of alternately turning on and off the semiconductor module by a control signal from the microcomputer to raise the temperature of the semiconductor module to a predetermined second temperature;
And a step of determining that the control of the microcomputer can be shifted to control of normal operation when the temperature of the semiconductor module exceeds the second temperature. Method. 6. The heating element according to claim 5, wherein the heating element is either a heater or a circuit including a part that generates heat among circuits constituting a controller including the control board and the inverter board . Control method of outdoor unit.

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