JPS6233240A - Operation control system for air conditioner - Google Patents

Abstract

PURPOSE:To ensure the service life of a capacity variable compressor and enable a smooth heating operation thereof, by decreasing setting values of operation current detecting means in response to a rise in outdoor temperatures by means of an outdoor temperature detecting means in the case of temperatures in excess of a predetermined temperature, thus, preventing a rise in pressures of a refrigeration cycle and that in temperatures of delivery gas. CONSTITUTION:In the case that outside temperatures are low and resistance values of temperature sensing resistance element 19 is high, diode 21 is in state of inversely biased; therefore, reference voltage (V-) of comparator 26 of operation current detecting circuit 27 is high, so that the capacity of the compressor is controlled with MSX control at a high current detection level (Hi). In the case that outdoor temperatures are higher than predetermined values, resistance values of the temperature sensing resistance element 19 becomes small, so that the diode 21 is biased in a forward direction to cause a conductive state, resulting in lower reference voltage (V-) of comparator 26. Consequently, the current detection level of operation current detecting circuit 27 is set at a low (Med) state. When the setting of thermostat 18 is changed so as to raise the room temperature under such conditions, capacity variable compressor 3 controls room temperature at predetermined temperature following the load of air conditioning with the capacity (MAX') limited at current detecting level (Med).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an operation control device for a heat pump type air conditioner that is equipped with a variable capacity compressor and performs cooling and heating operations.

2. Description of the Related Art Conventionally, the operation control circuit of this type of heat pump air conditioner (hereinafter simply referred to as an air conditioner) has generally been constructed as shown in the schematic electrical circuit diagram of a conventional example in FIG.

That is, in the summer, the l"ll' refrigeration cycle (not shown) is used as a cooling cycle, and the control circuit 101 operates as a variable voltage variable frequency power supply device (hereinafter simply referred to as an inverter) 10.
At the same time, an outdoor blower 104 (!: indoor blower 105) is connected to a power source 106 via a variable capacity compressor 103 via a power source 106. Then, the cooling operation shown in the time chart of FIG. 6 is performed.

Furthermore, in the winter, by switching the cooling/heating selector switch (not shown) to the heating side, the control circuit 101 switches the electromagnetic four-way valve 107 to ONL and the refrigeration cycle (not shown) to the heating cycle to perform the heating operation shown in FIG. Do the following. At the start of operation or when the air conditioning load suddenly increases (such as when changing temperature settings)
In this case, the variable capacity compression fi 103 performs high capacity operation. At this time, the operating current of the variable capacity compressor 103 is detected by a current transformer (hereinafter referred to as CT) 108, and control is performed so that the operating current does not exceed a predetermined value. Note 109
．． 110 and 111 are relay contacts, respectively.

Problems to be Solved by the Invention However, in an air conditioner with the operating current detection level fixed at a constant value as in the above configuration, there is a problem in that it is difficult to operate smoothly especially when the outside air temperature is high during the heating period. was there.

That is, an air conditioner generally has a heating capacity greater than a cooling capacity, and guarantees a predetermined capacity at low outside temperatures.

Therefore, when the outside temperature is relatively high, such as in early winter or early spring, the variable capacity compressor 103 operates at a small capacity (low speed). Even under such air conditioning load conditions, at the start of operation, high-capacity operation is performed within the allowable range of operating current, so the pressure in the refrigeration cycle increases and becomes overloaded, causing the discharge gas temperature to rise. Shorten compressor life. In addition, the transistors (not shown) that make up the in/out 102 may overheat, trip due to instantaneous overcurrent, and protective devices such as pressure switches may operate, making smooth operation difficult and interfering with heating. It becomes.

In view of the above problems, the present invention is configured to limit the high speed rotation range (high capacity) of the variable capacity compressor in response to (inversely proportional to) the rise in outside air temperature during heating operation to avoid overload conditions. The present invention provides an operation control device for an air conditioner.

Means for Solving the Problems In order to solve the above-mentioned problems, the air conditioner operation control device of the present invention is configured such that the outside temperature sensing means changes the set value of the current sensing means in accordance with the outside temperature. It is composed of

According to the configuration example described above, the present invention prevents overloading of the refrigeration cycle by reducing the maximum value of the operating current in accordance with the outside temperature when the outside temperature is higher than a predetermined value during heating operation. heating operation can be performed.

EXAMPLE Hereinafter, an explanation will be given based on FIGS. 1 to 4 showing an example of the present invention. Note that the operations of the refrigeration cycle and impark are well known, so their explanation will be omitted.

First, in the schematic electrical circuit diagram shown in Figure 3, the configuration is shown in the fifth section.
Since it is the same as the conventional example shown in the figure, a number is given by subtracting 100 from the number of the conventional example, and the explanation of its operation will be omitted. The details of the control circuit 1 are shown in FIG.

In FIG. 1, a microcomputer (hereinafter referred to as microcomputer) 15 is composed of a thermostat 18 which receives a temperature-sensitive resistance element 16 and a variable resistor 17 for temperature adjustment, a temperature-sensitive resistance element 19, a resistor 20, and a diode 21. The comparator 26 has a reference voltage controlled by an outside temperature detection circuit 22 as an input, and a voltage obtained by rectifying and smoothing the output of the CTa with a diode 23, a resistor 24, and a capacitor 25 as an input. An operating current detection circuit 27;
The operation switch 28 and the cooling/heating changeover switch 29 are respectively input, and the relay coils 9' corresponding to the relay contacts 9 to 11 are connected to each other.
A rotation command signal is outputted to the control output terminal 33 for starting and stopping the rotation command signals to the drivers 30 to 32 that respectively drive the motors 11' to 11' and the inverter 2. In addition, 34 to 37 are resistors, 38 is an oscillator, and 3
9 is a DC power supply.

Further, in the refrigeration cycle diagram of FIG. 4, 12 is an outdoor heat exchanger, 13 is an indoor heat exchanger, and 14 is a capillary tube.

In the above configuration, when the operation switch 28 is turned ON once while the cooling/heating changeover switch 29 in FIG. ONL, relay contact 9.
Turn on 10. As a result, the outdoor blower 4 and the indoor blower 5 shown in FIG. 3 are turned on. Furthermore, by driving the inverter 2 via the control output terminal 33 and turning on the variable capacity compressor 3, cooling operation is performed. At the start of operation, the room temperature is lowered with high capacity, and as the temperature approaches the setting temperature of the height-mostat 18, the capacity is reduced and ○N, O
Performs FF control. Note that the operating current detection circuit 27 has a high current detection level (Hl) because the outside air temperature detection circuit 22 is inactive. This state is shown in area A of the time chart in FIG.

When the cooling/heating changeover switch 29 is in the ON (H side) state, the microcomputer 15 turns on the relay coils 9', 10', and 11' via the drivers 30, 31, and 32, and the relay contacts 9.
Outdoor law by turning on 10.11! i@Turn on the machine 4, indoor blower 5, and electromagnetic four-way valve 7. Then, by operating the electromagnetic four-way valve 7, the refrigeration cycle shown in FIG. 4 is switched to a heating cycle. At the same time, the variable capacity compressor 3 is turned on to perform heating operation.

At this time, if the outside temperature is low and the resistance value of the temperature-sensitive resistance element 19 is large, the diode 21 is in a reverse bias state, so the reference voltage (V-) of the comparator 26 of the operating current detection circuit 27?
'i is high, so the compression function is operated under MAX control when the current detection level is high (Hi). In addition, the capacity of the %6 variable compressor 3 is reduced as the room temperature rises, and if the room temperature rises even at the lowest capacity, the thermostat 18 is turned on.
Make it FF. This state is shown in area B of the time chart in FIG.

If the outside temperature is higher than a predetermined value, the temperature-sensitive resistance element 19
The resistance value of the diode 21 becomes smaller, and the diode 21 becomes forward biased and becomes conductive, thereby acting to lower the reference voltage (V-) of the comparator 26. Therefore, the current detection level of the operating current detection circuit 27 is set to a low (Med) state.

In this state, if the daily setting of the thermostat is changed to raise the room temperature (when the air conditioning load suddenly increases), the variable capacity compressor 3 changes to the current detection level (Med) K'l1I
The J-limited capacity (MAX') follows the air conditioning load and controls the temperature to a predetermined temperature using VC. This state is shown by the time chart Cw in FIG. When the outside temperature further rises, the reference voltage (■-) of the comparator 26 decreases further, setting the current detection level to an even lower (LO) state and further reducing the compression function (MAX). The driving start state is shown in region D of the time chart in the figure.

Effects of the Invention As described above, the air conditioner operation control device of the present invention uses the outside air temperature sensing means to reduce the set value of the operating current sensing means in response to the rise in outside air temperature when the outside air temperature is higher than a predetermined temperature. This prevents pressure rises in the refrigeration cycle and discharge gas temperature during heating operation at high outside temperatures, guarantees the life of the variable capacity compressor, and maintains optimum capacity over a wide range of outside temperature conditions. Because of the control, it is possible to prevent overheating of the transistors of the inverter and prevent overcurrent tripping, and it is possible to perform a smooth and comfortable heating operation. Furthermore, wasteful high capacity can be reduced to save power.
It also has many advantages, such as being able to make more effective use of the characteristics of a variable capacity compressor.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an operation control device for an air conditioner according to an embodiment of the present invention, Fig. 2 is a time chart showing the operation status of the operation control device, and Fig. 3 is a schematic electrical circuit of the air conditioner. Figure 4 is the refrigeration cycle diagram of the air conditioner.
FIG. 5 is a schematic electrical circuit diagram of a conventional air conditioner, and FIG. 6 is a time chart showing the operating state of the same operation control device. G...I+J both circuits, 2...Inverter, 3...Variable capacity compressor, 8...Current transformer, 12...Outdoor Heat exchanger, 13...
・Indoor heat exchanger, 14...ki depilari tube, 15...microcomputer, 19...
...Temperature-sensitive resistance element, 20...Resistance, 21...
...Diode, 22...Outside temperature detection circuit, 26...Comparator, 29...
Cooling/heating switch. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
11 Control diagram Dark Figure 2 Figure 5 0B Figure 6

Claims (1)

[Claims] A refrigeration cycle is constructed by connecting the variable capacity compressor, an electromagnetic four-way valve for switching between cooling and heating, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger in a ring, and an inverter that drives the variable capacity compressor and an outdoor heat exchanger. An air conditioner is configured by providing an air blower and an indoor air blower, and is provided with an operating current detection means for the variable capacity compressor and an outside air temperature detection means, so that when the outside air temperature is equal to or higher than a predetermined value during heating operation, the outside air temperature is detected. An operation control device for an air conditioner, comprising a control circuit that reduces a set value of the operating current detection means in inverse proportion to a rise in the outside air temperature based on an output of the detection means.