JPH09210478A - Control device for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for air conditioner wherein a heating high pressure over-rising protective motion does not frequency generate, and the consumption power is less. SOLUTION: An air conditioner is equipped with a heat pump type refrigerating cycle which is constituted by communicating a capability variable compressor 1, a 4-way valve 2, an outdoor heat-exchanger, a decompressor, and an indoor heat- exchanger, etc., in order. The air conditioner is constituted in such a manner that by providing a temperature detector 13 which detects the piping temperature of the indoor heat-exchanger, when the piping temperature exceeds a specified set value, a control unit 18 performs a heating high pressure over-rising protective motion to decrease the allowable frequency of the capability variable compressor 1. In this case, a counter 19 which counts the number of times of the heating high pressure over-rising protective motion within a specified period of time, a maximum allowable frequency determining means 20 which determines the maximum allowable frequency of the capability variable compressor in response to the counted number, and a memory unit 21 which stores the maximum allowable frequency, are provided, and at the time of a normal operation, the operation frequency of the capability variable compressor is controlled with the maximum allowable frequency being stored in the memory unit as the upper limit.

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 equipped with a heat pump type refrigeration cycle of variable capacity, and more particularly to a device for reducing the number of heating high pressure overheating protection operations during heating operation.

[0002]

2. Description of the Related Art Conventionally, as shown in a refrigeration cycle diagram of FIG. 1, a control device for an air conditioner having a heat pump type refrigeration cycle of variable capacity has a variable capacity compressor 1, a four-way valve 2, and an outdoor heat exchange. Vessel 3, pressure reducer 4, and indoor heat exchanger 5
As shown in the block diagram of FIG. 9, a set temperature (Ts)
And the like, an indoor temperature detector 12 for detecting an indoor temperature (Tr), a temperature detector 13 for detecting a pipe temperature (Tp) of the indoor heat exchanger 5, and a commercial power supply 30.
Circuit 14 for driving the variable capacity compressor 1 by switching at a predetermined frequency, an inverter drive circuit 15 for driving the inverter circuit 14 at a predetermined frequency, and an indoor fan drive for driving the indoor fan 7. Circuit 1
6 and a four-way valve drive circuit 17 for driving the four-way valve 2,
The control unit 18 is configured to change the operation allowable frequency of the variable capacity compressor according to the difference (load) between the room temperature (Tr) and the set temperature (Ts) to set the room temperature (Tr) and the set temperature. The comfort is maintained by raising or lowering the operating frequency by controlling with the time (rate) change rate of the difference (load) from (Ts) and the room temperature (Tr). However, in such an air conditioner, when a heating overload occurs during heating operation, the operating frequency of the variable capacity compressor rises, the capacity of the compressor increases, and the high-pressure side pressure rises abnormally, the variable capacity compressor Since there is a risk of destruction of 1 etc., the pipe temperature (Tp) of the indoor heat exchanger 5 is detected, that is, the high-pressure side pressure is indirectly detected, and the pipe temperature (Tp) is detected.
Exceeds a predetermined set value (Tps), the operating frequency of the variable capacity compressor 1 is forcibly reduced to a predetermined value to perform the heating high pressure overheat protection operation. However, if the heating high pressure overheat protection operation frequently occurs as described above and the operating frequency of the variable capacity compressor is changed, there is a problem that power consumption increases.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and improves heating efficiency without lengthening the operating frequency abnormally by frequently causing unnecessary heating high pressure overheat protection operation. It is an object of the present invention to provide a control device for an air conditioner that has a long life.

[0004]

In order to solve the above problems, the present invention provides a variable capacity compressor, a four-way valve, an outdoor heat exchanger,
A heat pump type refrigeration cycle in which a decompressor, an indoor heat exchanger, etc. are sequentially communicated with each other, and the operating frequency of the variable capacity compressor is controlled according to the load, and the piping temperature of the indoor heat exchanger is controlled. Equipped with a temperature detector to detect
When the pipe temperature exceeds a predetermined set value, the operating frequency of the variable capacity compressor is lowered by a predetermined value according to the operating frequency when the set temperature exceeds the predetermined set value to perform heating high pressure overheat protection operation. In the compressor, a counter for counting the number of times of the heating high pressure overheating protection operation within a predetermined time, a maximum permissible frequency determining means for determining the maximum permissible frequency of the variable capacity compressor according to the count number, and a maximum permissible frequency. A maximum allowable frequency storage unit for storing the frequency is provided, and during normal operation, the maximum allowable frequency is controlled as the upper limit value of the operating frequency of the variable capacity compressor.

The maximum allowable frequency determining means is
A table that stores a frequency that increases or decreases with respect to the number of times in advance, and a calculation unit that calculates a new maximum allowable frequency by adding the frequency from the table to the maximum allowable frequency stored in the storage unit that stores the maximum allowable frequency. I made it consist of.

Further, the maximum allowable frequency determining means is
When the absolute maximum frequency storage unit for storing the absolute maximum frequency of the variable capacity compressor and a comparison unit are provided, the absolute maximum frequency is compared with a new maximum allowable frequency, and the new maximum allowable frequency exceeds the absolute maximum frequency. Made the absolute maximum frequency a new maximum allowable frequency.

[0007]

With the above construction, the control device for an air conditioner of the present invention detects the pipe temperature of the indoor heat exchanger during heating operation, and when the pipe temperature exceeds a predetermined set temperature, the capacity is exceeded. The heating high pressure overheat protection operation that reduces the operating frequency of the variable compressor is performed, the number of times of the heating high pressure overheat protection operation within a predetermined time is counted, and the maximum allowable frequency of the variable capacity compressor is determined according to the count number. To prevent the high pressure of the indoor heat exchanger from becoming overpressure by limiting the operating frequency of the variable capacity compressor at the maximum allowable frequency.
It is possible to reduce the number of heating high-voltage overheat protection operations.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner control apparatus according to the present invention will be described below in detail with reference to the drawings. FIG. 2 is a block diagram showing an embodiment of a control device for an air conditioner according to the present invention. As shown in the refrigeration cycle diagram of FIG. 1, a control device for an air conditioner having a variable capacity heat pump type refrigeration cycle according to the present invention includes a variable capacity compressor 1, a four-way valve 2, an outdoor heat exchanger 3, and a decompression device. The heat pump type refrigerating cycle in which the vessel 4, the indoor heat exchanger 5 and the like are sequentially connected to each other is provided, and as shown in the block diagram of FIG. 2, the operation unit 11 for inputting the set temperature (Ts) and the indoor temperature ( Indoor temperature detector 12 for detecting Tr) and the pipe temperature (T) of the indoor heat exchanger 5.
p) and the variable capacity compressor 1 by switching the rectified voltage obtained by rectifying the commercial power source 30 and the temperature detector 13.
Inverter circuit 14 for driving the
4 drives at a predetermined operating frequency (f), an inverter drive circuit 15 that drives the indoor fan 7, and a four-way valve drive circuit 17 that drives the four-way valve 2.
In addition to the control unit 18, a counter 19 that counts the number of times (n) the heating high pressure overheat protection operation is performed within a predetermined time.
And a maximum frequency determining means 20 for determining the maximum permissible frequency (famax) of the variable capacity compressor according to the same count number, a storage unit 21 for storing the maximum permissible frequency (famax) and the predetermined time. Timer 22
The maximum allowable frequency (fama) is set during normal operation.
x) is the upper limit of the operating frequency (f) that controls the variable capacity compressor 1.

The maximum allowable frequency determining means 20 is shown in FIG.
As shown in FIG. 4, a change table 201 that stores a change frequency (Δf) that increases or decreases with respect to the number of times in advance, and a maximum allowable frequency (famax) that stores the change frequency (Δf) from the change table 201 in the storage unit 21. To the new maximum allowable frequency (famax '= fama
x + Δf) and the arithmetic unit 202 for calculating.

Further, the maximum allowable frequency determining means 20
Is the absolute maximum frequency (Fma of the variable capacity compressor 1).
x) is stored in the absolute frequency storage unit 203 and the comparison unit 204.
And the absolute maximum frequency (Fmax) stored in the absolute frequency storage unit 203 in the comparison unit 204 and the calculation unit 202.
When the new maximum allowable frequency (famax ') exceeds the absolute maximum frequency (Fmax) (famax'> Fm)
ax), the maximum allowable frequency (Fmax) is set as a new maximum allowable frequency (famax ′).

The operation of the above structure will be described below. First, the normal operation will be described. FIG. 5 shows the allowable frequency (fa) with respect to the difference (Tl = (load)) between the indoor temperature (Tr) and the set temperature (Ts) during normal operation, and the maximum allowable frequency (famax) is the difference (Tl =
If the (load) is greater than a certain value, it is set to a constant value.
FIG. 6 shows the difference (T) between the room temperature (Tr) and the set temperature (Ts).
l = (load)) and the temporal change rate (Δ) of the room temperature (Tr)
Tr) as a parameter, and the change frequency is stored in the storage unit 21.
The operation table stored in FIG. As shown in the figure, the difference (Tl) between the room temperature (Tr) and the set temperature (Ts)
= (Load)), the allowable frequency (fa) is calculated, and the difference (T) between the room temperature (Tr) and the set temperature (Ts) is calculated.
l = (load)) and the temporal change rate (ΔTr) of the room temperature (Tr), the change frequency (Δf) with respect to the current operating frequency (f) is obtained by referring to the operation table, and the allowable frequency (fa) is obtained. ) Is the upper limit, and the variable capacity compressor 1 is controlled by determining the operating frequency (f).

Next, the heating high pressure overheating protection operation will be described. Now, during heating operation, when the difference (Tl = (load)) between the room temperature (Tr) and the set temperature (Ts) becomes large and the heating overload condition occurs, the operating frequency (f) is increased to the maximum allowable frequency (famax). The variable capacity compressor 1 is controlled to operate at the maximum capacity. At this time, as shown in FIG. 7, the pipe temperature (Tp) is set to a predetermined set value (Tp).
s) (Tp> Tps), the allowable frequency (fa) of the variable capacity compressor 1 is referred to the heating high pressure overheating protection operation table stored in the storage unit 21 shown in FIG. Allowable frequency determined for (f) (fa =
forcibly lowering to the same allowable frequency (fa = f
The variable capacity compressor 1 is controlled by determining the operating frequency (f) whose upper limit is (ad).

Next, the operation in the case where the heating high pressure overheating protection operation repeatedly occurs will be described with reference to the operation flow of FIG. As shown in the operation flow of FIG. 3, the timer 22 is set (S1), and the counter 19 counts the number (n) of the heating high pressure overheat protection operations that occur within a predetermined time (for example, 1 hour) (S2). ), The variable frequency (Δfn = Δf3) with respect to the number of times (n = 3) is obtained (S3) by referring to the contents of the correction table 201 shown in FIG. Is added to the maximum allowable frequency (famax) stored in the storage unit 21 to obtain a new maximum allowable frequency (famax '= famax +).
Δf3) is calculated (S4), and the storage unit 21 is rewritten to the new maximum allowable frequency (famaxn) (S4).
5) During normal operation, the new maximum allowable frequency (fama)
The operating frequency (f) of the variable capacity compressor 1 is controlled by setting x ′) to the upper limit of the operating frequency (f).

Further, the new maximum allowable frequency (famax '= famax + Δf3) obtained by the addition is stored in the absolute frequency storage unit 203 in the absolute maximum frequency (Fma).
x) and the new maximum allowable frequency (fam)
ax ') becomes larger than the absolute maximum frequency (Fmax) (famax'> Fmax), the absolute maximum frequency (Fmax) is changed to a new maximum allowable frequency (famax '=
Fmax) (S7).

The contents of the correction table shown in FIG. 4 may be (-Δf) when the number of times is a predetermined number (ns) or more (n> ns), and may be (0) when the number of times is less than the predetermined number (n <ns). It goes without saying that the good things are.

[0016]

As described above, according to the control device for an air conditioner of the present invention, the pipe temperature of the indoor heat exchanger is detected during the heating operation, and when the pipe temperature exceeds a predetermined set temperature. Performs a heating high pressure overheat protection operation that lowers the allowable frequency of the variable capacity compressor, counts the number of heating high pressure overheat protection operations within a predetermined time, and according to the count, the maximum allowable capacity variable compressor By determining the frequency and limiting the maximum allowable frequency of the variable capacity compressor, it is possible to prevent the high pressure of the indoor heat exchanger from becoming overpressure and reduce the number of heating high pressure overheat protection operations. It is possible to provide a control device for an air conditioner that can improve heating efficiency and extend the life of the device without causing a high-voltage overheating protection operation frequently to raise or lower the operating frequency abnormally.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram showing a refrigeration cycle of an air conditioner.

FIG. 2 is a block diagram showing an embodiment of a control device for an air conditioner of the present invention.

FIG. 3 is an operation flowchart of the control device for an air conditioner of the present invention.

FIG. 4 is a diagram showing an example of contents of a correction table of the control device for an air conditioner of the present invention.

FIG. 5 is a diagram showing an allowable frequency with respect to a difference (load) between an indoor temperature and a set temperature.

FIG. 6 is a diagram showing an example of contents of an operation table.

FIG. 7 is a diagram showing a heating high pressure overheating protection operating temperature of a pipe temperature (Tp).

FIG. 8 is a diagram showing an example of contents of a heating high pressure overheat protection operation table.

FIG. 9 is a block diagram showing a control device for a conventional air conditioner.

[Explanation of symbols]

 1 Variable capacity compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Pressure reducer 5 Indoor heat exchanger 6 Outdoor fan 7 Indoor fan 11 Operating part 12 Indoor temperature detector 13 Heat exchanger temperature detector 14 Inverter circuit 15 Inverter drive circuit 16 Indoor fan drive circuit 17 Four-way valve drive circuit 18 Control section 19 Counter 20 Maximum allowable frequency determination means 21 Storage section 22 Timer 201 Change table 202 Calculation section 203 Absolute frequency storage section 204 Comparison section

Claims (3)

[Claims] 1. A heat pump type refrigeration cycle in which a variable capacity compressor, a four-way valve, an outdoor heat exchanger, a decompressor, an indoor heat exchanger and the like are sequentially connected to each other, and the variable capacity compressor is Which controls the operating frequency,
A temperature detector for detecting the pipe temperature of the indoor heat exchanger is provided, and when the pipe temperature exceeds a predetermined set value, the operating frequency of the variable capacity compressor is set to the operating frequency when the set temperature is exceeded. In an air conditioner that performs a heating high pressure overheat protection operation by lowering a predetermined value according to the counter, a counter that counts the number of times of the heating high pressure overheat protection operation within a predetermined time, and the capacity variable compressor according to the count number. A maximum allowable frequency determining means for determining a new maximum allowable frequency of, and a maximum allowable frequency storage unit for storing the new maximum allowable frequency,
An air conditioner control device characterized in that during normal operation, the maximum allowable frequency stored in the maximum allowable frequency storage section is controlled as an upper limit of the operating frequency of the variable capacity compressor. 2. The maximum permissible frequency determining means adds in advance a table that stores frequencies that increase or decrease with respect to the number of times, and a frequency from the table to the maximum permissible frequency stored in a storage unit that stores the maximum permissible frequency. The control device for an air conditioner according to claim 1, further comprising a calculation unit that calculates a new maximum allowable frequency. 3. The maximum allowable frequency determining means includes an absolute maximum frequency storage section for storing an absolute maximum frequency of the variable capacity compressor and a comparing section, and compares the absolute maximum frequency with a new maximum allowable frequency. The air conditioner control device according to claim 2, wherein when the new maximum allowable frequency exceeds the absolute maximum frequency, the absolute maximum frequency is set as the new maximum allowable frequency.