JP3098789B2 - Control device for air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an air conditioner having an inverter device for controlling the number of revolutions of a compressor.

[0002]

2. Description of the Related Art In recent years, a large number of air conditioner control devices for controlling the capacity by increasing or decreasing the number of revolutions of a compressor by using an inverter device for changing the frequency of a power supply have been used. Conventional techniques include, for example, Japanese Utility Model Laid-Open No. 58-1535.
No. 89 publication.

Hereinafter, an example of the control device of the air conditioner described above will be described with reference to the drawings. FIG. 4 is a schematic configuration diagram of a conventional air conditioner control device, FIG. 5 is an operation flowchart thereof, and FIG. 6 is a diagram showing a change over time of a power element case temperature of the inverter circuit and a compressor / outdoor fan operating state. is there.

In FIG. 4, reference numeral 1 denotes a three-phase commercial AC power supply;
Reference numeral 2 denotes a converter circuit for converting AC power into DC power, and a commercial AC power supply 1 is connected to an AC input unit. 3 is an inrush current limiting resistor, 4 is an inrush current limiting relay, 5 is an electrolytic capacitor for smoothing DC power, and an inrush current limiting resistor 3 is connected in parallel with the inrush current limiting relay 4 and has one end connected to the positive side of the converter circuit 2. The other end is connected to the positive electrode side of the electrolytic capacitor 5. The negative side of the electrolytic capacitor 5 is connected to the negative side of the converter circuit 2. Reference numeral 6 denotes an inverter circuit which inputs the DC power smoothed by the electrolytic capacitor 5, converts the DC power into three-phase AC power, and outputs it to the compressor 7.

[0005] Reference numeral 8 denotes an indoor heat exchanger for exchanging heat of the refrigerant from the compressor 7, and 9 denotes an outdoor heat exchanger for exchanging heat of the refrigerant from the indoor heat exchanger 8 and returning the refrigerant to the compressor 7. Reference numeral 10 denotes an outdoor fan that cools the outdoor heat exchanger 9 and the inverter circuit.

Reference numeral 11 denotes temperature detecting means for detecting the temperature of the power element case of the inverter circuit 6. Reference numeral 12 denotes an operation command input unit for determining operation / stop of the compressor, 13 denotes inverter control means, 14 denotes relay driving means, and 15 denotes voltage detection means for detecting the voltage of the electrolytic capacitor 5. The inverter control unit 13 receives signals from the operation command input unit 12 and the voltage detection and detection unit 15 and outputs a signal to the relay driving unit 14. Relay driving means 14 outputs a signal to inrush current limiting relay 4.

Reference numeral 16 denotes a base drive driving means, which inputs signals from the inverter control means 13 and the temperature detection means 11 and outputs signals to the inverter circuit 6. Reference numeral 17 denotes an outdoor fan drive unit which receives a signal from the base drive drive unit 16 and outputs a signal to the outdoor fan 10.
The operation will be described with reference to FIG. In FIG. 5, first, in step a, the commercial AC power supply 1 is turned on. Next, in step b, a signal S1 is input from the operation command input unit 12.
Is output to the inverter control means 13, and if "operation", the logic returns to step c. Otherwise, the logic returns to step b.
Next, in step c, the electrolytic capacitor 5 is charged via the converter circuit 2 and the inrush current limiting resistor 3, the charging voltage is detected by the voltage detecting means 15, and the signal S4 is output to the inverter controlling means 13 so as to output the charging voltage. Is greater than or equal to the specified voltage, return to step d, otherwise return to step c.

Next, at step d, the inverter control means 13
A signal S2 is output to the relay driving means 14, and a signal S3 is output from the relay driving means 14 to the inrush current limiting relay 4.
To turn on the inrush current limiting relay 4. Next, in step e, the signal S5 is output from the inverter control means 13 to the base drive drive means 16 to determine the operation frequency.

Next, at step f, the signal S6 is output to the inverter circuit 6 by the base drive driving means 16, and the power obtained by converting the direct current into three-phase alternating current from the inverter circuit 6 is supplied to the compressor 7, and the compressor 7 Starts driving. At this time, the outdoor fan driving means 17 outputs the signal S6
Is input to output a signal S7 to the outdoor fan 10, and the outdoor fan 10 starts operating.

Next, at step g, the temperature detecting means 11
To detect the power element case temperature of the inverter circuit 6 (hereinafter, this temperature is referred to as Tc) and output it to the base drive driving means 16 as a signal S8. If (Equation 1) is satisfied, the process proceeds to step h. In this case, the logic proceeds to step f.

[0011]

(Equation 1)

Here, T0 is smaller than the maximum allowable case temperature of the power element (hereinafter, this temperature is referred to as Tcmax).
The value is set in consideration of the overshoot of c.

Next, at step h, the signal S6 is outputted from the base drive driving means 16 to the inverter circuit 6 and to the outdoor fan driving means 17, so that the compressor 7 and the outdoor fan 10 are stopped. Next, in step i, the power element case temperature Tc is detected by the temperature detecting means 11 and output to the base drive driving means 16 as a signal S8. If (Equation 2) is satisfied, go to step e; otherwise, go to step e. Advance the logic to h.

[0014]

(Equation 2)

Here, T1 is a value smaller than T0 described above. FIG. 6 shows the change over time of the power element case temperature of the inverter circuit and the compressor / outdoor fan operating state in the above-described steps e to i.

[0016]

However, in the above-mentioned conventional configuration, the case temperature set value of the power element protection is low, and the power element cannot be used up to the maximum capacity. However, there is a disadvantage that the load on the system due to the repeated start / stop of the compressor increases.

The present invention solves the above-mentioned conventional problems and provides a control device for an air conditioner that uses a power element up to the maximum capacity to extend the compressor operating time and eliminate the load on the system due to the stop of the compressor. To provide.

[0018]

In order to achieve this object, a control device for an air conditioner according to the present invention comprises a temperature detecting means for detecting a case temperature of a power element of an inverter circuit, and a signal from the temperature detecting means. Detected temperature determination means to be input, outdoor fan control means to receive signals from the base drive drive means and detected temperature determination means, and an outdoor fan to receive signals from the outdoor fan control means and to output signals to the outdoor fan It has a driving means.

The detected temperature determining means compares the detected temperature of the temperature detecting means with a plurality of predetermined values, and the outdoor fan control means switches the air flow of the outdoor fan in accordance with the result of the determination by the detected temperature determining means. It controls the outdoor fan driving means.

[0020]

With this configuration, the temperature of the power element case of the inverter circuit is detected by the temperature detecting means, and the rise rate of the case temperature is determined by the detected temperature determining means. Based on the determination result, the outdoor fan control means determines the air flow of the outdoor fan. Can be determined.

[0021]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a control device of an air conditioner according to an embodiment of the present invention, FIG. 2 is an operation flowchart thereof, and FIG. 3 shows a temporal change of a power element case temperature of an inverter circuit and an outdoor fan operating state. FIG.

In FIG. 1, reference numeral 101 denotes a three-phase commercial AC power supply, and reference numeral 102 denotes a converter circuit for converting AC power into DC power. The commercial AC power supply 101 is connected to an AC input unit.

Inrush current limiting resistor 103, inrush current limiting relay 104, electrolytic capacitor 105 for smoothing DC power, inrush current limiting resistor 103 is connected in parallel with inrush current limiting relay 104 and has one end connected to converter circuit 102.
And the other end is connected to the positive electrode side of the electrolytic capacitor 105. The negative side of the electrolytic capacitor 105 is connected to the negative side of the converter circuit 102. An inverter circuit 106 inputs the DC power smoothed by the electrolytic capacitor 105, converts the DC power into three-phase AC power, and outputs the three-phase AC power to the compressor 107.

Reference numeral 108 denotes an indoor heat exchanger for exchanging heat of the refrigerant from the compressor 107, and 109 denotes an indoor heat exchanger.
An outdoor heat exchanger that exchanges heat from the refrigerant and returns the refrigerant to the compressor 107. An outdoor fan 110 cools the outdoor heat exchanger 109 and the inverter circuit.

Reference numeral 111 denotes a temperature detecting means for detecting the temperature of the power element case of the inverter circuit 106. An operation command input unit 112 determines operation / stop of the compressor.
Is inverter control means, 114 is relay drive means, 11
Reference numeral 5 denotes voltage detecting means for detecting the voltage of the electrolytic capacitor 105.

The inverter control means 113 receives signals from the operation command input unit 112 and the voltage detection and detection means 115 and outputs signals to the relay drive means 114. Relay driving means 114 outputs a signal to inrush current limiting relay 104. Reference numeral 116 denotes a base drive driving unit which inputs a signal from the inverter control unit 113 and
6 to output a signal.

Reference numeral 117 denotes a detected temperature judging unit which receives a signal from the temperature detecting unit 111 as an input. Reference numeral 118 denotes a detected temperature determination unit 117 and a base drive driving unit 11
This is an outdoor fan control unit that receives a signal from the control unit 6 as an input.
119 is an outdoor fan drive unit, which is an outdoor fan control unit 1
The signal from the controller 18 is input and the signal is output to the outdoor fan 110.

The operation of the control device for an air conditioner configured as described above will be described below with reference to FIGS. In FIG. 2, first, in step 1, the commercial AC power supply 101 is turned on. Next, in step 2, the signal S <b> 11 from the operation command input unit 112 is
If it is "operation", the logic returns to step 3; otherwise, the logic returns to step 2.

Next, in step 3, the electrolytic capacitor 105 is charged via the converter circuit 102 and the inrush current limiting resistor 103, and the charged voltage is detected by the voltage detecting means 1.
15 and outputs the signal S1 to the inverter control means 113.
4 is output. If the charging voltage is equal to or higher than the specified voltage, the flow returns to step 4; otherwise, the flow returns to step 3.

Next, at step 4, the inverter control means 11
3, the signal S12 is output to the relay driving means 114, and the signal S13 is output from the relay driving means 114 to the inrush current limiting relay 104, and the inrush current limiting relay 104 is turned on.
N. Next, in step 5, the signal S15 is output from the inverter control means 113 to the base drive driving means 116.
Output to determine the operating frequency.

Next, at step 6, a signal S16 is output from the base drive driving means 116 to the inverter circuit 106 and the outdoor fan control means 118, and the power obtained by converting the direct current into three-phase alternating current from the inverter circuit 106 to the compressor 107. The compressor 107 is supplied and starts operating.
The outdoor fan control means 118 outputs a signal S17 to the outdoor fan drive means 119, and outputs the signal S17 to the outdoor fan drive means 11
9 outputs a signal S18 to start the operation of the outdoor fan 110 with the weakest wind.

Next, at step 7, the temperature detecting means 11
1, the temperature of the power element case of the inverter circuit 106 (hereinafter, this temperature is referred to as Tc) is detected and output to the detected temperature determination means 14 as a signal S19. If (Equation 3) is satisfied, the process proceeds to step 8; If so, the logic proceeds to step 6.

[0033]

(Equation 3)

Here, T2 is a preset value. Next, in step 8, a signal S20 is output from the detected temperature determination means 117 to the outdoor fan control means 118, and a signal S17 is output from the outdoor fan control means 118 to the outdoor fan drive means 119. Become. Next, at step 9, the case temperature Tc is detected by the temperature detecting means 111 and output to the detected temperature determining means 117 as a signal S19. If (Equation 4) is satisfied, go to step 10; otherwise, go to step 8. Advance the logic.

[0035]

(Equation 4)

Here, T3 is a value obtained from the power element case temperature rise rate θ1 during the outdoor fan low wind operation. As shown in FIG. 3, the rate of increase θ1 is (T3-T2) / (t2-t
1).

Next, at step 10, a signal S20 is outputted from the detected temperature judging means 117 to the outdoor fan control means 118, and a signal S1 is outputted from the outdoor fan control means 118.
7 to the outdoor fan driving means 119 to output the outdoor fan 1
10 is a middle wind operation. Next, in step 11, the case temperature Tc is detected by the temperature detecting means 111, and is output to the detected temperature determining means 117 as a signal S19. If (Equation 5) is satisfied, the process proceeds to step 12, otherwise the process proceeds to step 1.
Advance logic to zero.

[0038]

(Equation 5)

Here, T4 is a value obtained from the case temperature rise rate θ2 during the outdoor fan middle air operation. Next, in step 12, the signal S20 is output from the detected temperature determination means 117 to the outdoor fan control means 118, and the signal S17 is output from the outdoor fan control means 118 to the outdoor fan drive means 119, so that the outdoor fan 110 operates in a strong wind. .

Next, at step 13, the temperature detecting means 1
11, the case temperature Tc is detected and output as a signal S19 to the detected temperature determining means 117. If (Equation 6) is satisfied, the process proceeds to step 14, otherwise the process proceeds to step 12.

[0041]

(Equation 6)

Here, T5 is a value obtained from the rise rate θ3 of the case temperature during the compressor strong wind operation. Then step 14
The signal S20 is output from the detected temperature determination means 117 to the outdoor fan control means 118, and the outdoor fan control means 1
The signal S17 is output to the outdoor fan driving means 119 from 18, and the outdoor fan 110 operates in the strongest wind operation. At this time, the maximum allowable case temperature of the power element (hereinafter referred to as Tcmax)
) Is a value that takes into account the overshoot at the start of the strongest wind operation.

Next, at step 15, the temperature detecting means 1
11, the case temperature Tc is detected and output to the detected temperature determining means 117 as a signal S19. If (Equation 7) is satisfied, the process proceeds to Step 6; otherwise, the process proceeds to Step 14.

[0044]

(Equation 7)

FIG. 3 shows the time-dependent change of the temperature of the power element case of the inverter circuit and the operation state of the outdoor fan in the above-mentioned operations of steps 5 to 15.

As described above, according to the present embodiment, the signal S19 is inputted from the temperature detecting means 111 for detecting the case temperature of the power element of the inverter circuit 6 to the detected temperature judging means 117, and the signal S19 is outputted from the detected temperature judging means 117 to the outdoor. By providing a configuration in which the signal 20 is input to the fan control means 118 and the signal S17 is further input to the outdoor fan drive means 119 from the outdoor fan control means 118, the operating air flow rate of the outdoor fan 110 is varied to allow the maximum allowable power element case. The power element can be used at the maximum capacity near the temperature, and the operation time can be extended without stopping the compressor 107.

Although the air flow rate of the outdoor fan is switched in five steps, the air flow rate may be set in consideration of the capacity of the system.

[0048]

As described above, the present invention provides a temperature detecting means for detecting a case temperature of a power element of an inverter circuit, a detected temperature determining means for receiving a signal from the temperature detecting means, a base drive driving means, An outdoor fan control unit that receives a signal from the detected temperature determination unit and an outdoor fan drive unit that receives a signal from the outdoor fan control unit and outputs a signal to the outdoor fan, wherein the detection temperature determination unit is a temperature detection unit. The detected temperature and a plurality of predetermined values are compared and determined, and the outdoor fan control means controls the outdoor fan driving means so as to switch the air flow of the outdoor fan in accordance with the determination result of the detected temperature determining means.

This makes it possible to use the power element up to the maximum capacity, to continuously operate the compressor without stopping, and to provide an excellent air conditioner control device that does not generate a load on the system due to repeated start / stop of the compressor. Can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a control device of an air conditioner according to an embodiment of the present invention.

FIG. 2 is an operation flowchart of the control device for the air conditioner of the embodiment.

FIG. 3 is a characteristic diagram showing a temporal change of a power element case temperature and an outdoor fan operating state of the air conditioner control device of the embodiment.

FIG. 4 is a schematic configuration diagram of a conventional control device for an air conditioner.

FIG. 5 is an operation flowchart of a conventional air conditioner control device.

FIG. 6 is a characteristic diagram showing a temporal change of a power element case temperature and a compressor / outdoor fan operating state of a conventional air conditioner control device.

[Explanation of symbols]

 Reference Signs List 101 three-phase commercial AC power supply 102 converter circuit 103 inrush current limiting resistor 104 inrush current limiting relay 105 electrolytic capacitor 106 inverter circuit 107 compressor 108 indoor heat exchanger 109 outdoor heat exchanger 110 outdoor fan 111 temperature detecting means 112 operation Command input section 113 Inverter control means 114 Relay drive means 115 Voltage detection means 116 Base drive drive means 117 Detected temperature determination means 118 Outdoor fan control means 119 Outdoor fan drive means

Claims (1)

(57) [Claims] A converter circuit for converting AC power into DC power; an inrush current limiting resistor having one end connected to a positive electrode side of the converter circuit; and a converter circuit connected to the other end of the inrush current limiting resistor. An electrolytic capacitor for smoothing the converted DC power, an inrush current limiting relay connected in parallel with the inrush current limiting resistor, and the DC power smoothed by the electrolytic capacitor is input and converted to three-phase AC power. An inverter circuit that controls the compressor, an outdoor heat exchanger and an indoor heat exchanger that perform heat exchange of the refrigerant from the compressor, and an outdoor fan for cooling the outdoor heat exchanger and the inverter circuit, An operation command input unit for determining operation / stop of the compressor, voltage detection means for detecting the voltage of the electrolytic capacitor, and signals from the operation command input unit and the voltage detection means An inverter control means for inputting a signal from the inverter control means, a relay driving means for receiving a signal from the inverter control means and outputting a signal to the inrush current limiting relay, and a signal from the inverter control means as an input and transmitting a signal to the inverter circuit. Base drive driving means for outputting, temperature detecting means for detecting a case temperature of a power element of the inverter circuit, detected temperature determining means for receiving a signal from the temperature detecting means as input, the base drive driving means and the detecting means An outdoor fan control unit that receives a signal from a temperature determination unit as input, and an outdoor fan drive unit that receives a signal from the outdoor fan control unit and outputs a signal to the outdoor fan, and the detected temperature determination unit includes The outdoor fan control means compares the detected temperature of the temperature detection means with a plurality of predetermined values, and Degree determining means determination result control device for an air conditioner and controls the outdoor fan driving unit to switch the air volume of the outdoor fan according to.