JPS6233238A - 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 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 the refrigeration cycle and in temperatures of delivery gas. CONSTITUTION:In the case that outdoor temperature is low and resistance value of a tempera ture sensing resistance element 19 is high, input voltage > reference voltage, and a comparator 22 is in a state of Hi output; therefore, the reference voltage (V-) of a comparator 27 of a operation current detecting circuit 28 is high, so that MAX control operation is carried out at a high current detection level (Hi). In the case that outdoor temperature is higher than a predetermined value, resistance values of the temperature sensing resistance element 19 are small, comparator 22 is in a state of L0 output, leading to a lower reference voltage (V-) of the compatator 27 through a resistance 39. Accordingly, the current detection level of the operation current detecting circuit 28 is set at a state of low (L0). When, under such condition, the setting of thermostat 18 is changed so as to raise the room temperature (when load of air conditioning is abruptly increased), a capacity variable compressor 3 controls temperatures of the room at a predetermined temperature, following the load of air condition ing with the capacity (MAX') limited by the current detecting level (L0).

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 Conventional heat pump air conditioners of this type (hereinafter simply referred to as air conditioners) have generally been constructed as shown in the schematic electrical circuit diagram of a conventional example shown in FIG.

That is, in the summer, the refrigeration cycle (not shown) is used as a cooling cycle, and the control circuit 101 drives a variable capacity compressor 103 via a variable voltage variable frequency power supply (hereinafter simply referred to as an inverter) 1o2, and also operates one outdoor blower. 104 and an indoor blower 105 are connected to a power source 106. Then, the cooling operation shown in the time chart of FIG. 6 is performed.

Further, in winter, by switching the cooling/heating selector switch (not shown) to the heating side, the control circuit 101 turns on the electromagnetic four-way valve 107, and changes the refrigeration cycle (not shown) to the heating cycle as shown in FIG. Drive. 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 compressor 103 performs high capacity operation.

At this time, the operating current of the variable capacity compressor 103 is changed to a current transformer (
(hereinafter referred to as CT) 108, and control is performed so that the operating current does not exceed a predetermined value. In addition, 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.

Transistors (not shown) constituting the small inverter 102 may overheat, trip due to instantaneous overcurrent, and protective devices such as pressure switches may operate, making smooth operation difficult and causing problems with heating. There is.

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

Means for Solving the Problems In order to solve the above problems, the air conditioner operation control device of the present invention is configured to change the set value of the current detection means by the outside temperature detection means. .

According to the above-described configuration, the present invention prevents overload of the refrigeration cycle by reducing the maximum value of the operating current when the outside temperature is higher than a predetermined value during heating operation, and can perform smooth heating operation. .

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 in the figure, the number of the conventional example))10
A number with 0 subtracted will be assigned and the explanation of its operation will be omitted. The details of the control circuit 1 are shown in FIG.

In FIG. 1, a 15-bit microcomputer (hereinafter referred to as microcomputer), a thermostat 18 whose inputs are a temperature-sensitive resistance element 16 and a temperature-adjusting variable resistor 17, an input voltage from a temperature-sensitive resistance element 19, and resistors 20, 21. The reference power controlled by the outside temperature detection circuit 23 composed of the comparator 22 which compares the reference voltage by An operating current detection circuit 28 consisting of a comparator 27 which uses the obtained electric power as an input (g), an operating switch 29 and a cooling/heating changeover switch 30 as inputs, and relay coils 9' to 11' corresponding to relay contacts 9 to 11; A rotation command signal is outputted to the control output terminal 34 that starts and stops rotation command signals to the drivers 31 to 33 and the inverter 2, respectively. Also, 35 to 40 are resistors, 41 is a capacitor, 42 is an oscillation N, and 43 is a DC power supply. It is.

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 29 is turned ON once while the cooling/heating changeover switch 30 in FIG. Turn on and relay contact 9
．． By turning on the air blower 10, the outdoor fan 4 and the indoor fan 5 shown in FIG. 3 are turned on. Furthermore, the inverter 2 is driven via the control output terminal 34, and the variable capacity compressor 3 is turned on to perform cooling operation.

At the start of operation, the room temperature is lowered with high capacity, and as the temperature approaches the set temperature of the thermostat 18, the capacity is reduced and ON/OFF control is performed at a predetermined temperature. Note that the operating current detection circuit 28 has a high current detection novelty (Hl) because the outside temperature detection circuit 23 is inoperative.

This state is shown in area A of the time chart in FIG.

When the cooling/heating changeover switch 30 is in the 0N (H side) state, the microcomputer 15 turns on the relay coils 9ζ 10' and 1i via the drivers 31, 32, and 33, and the relay contacts 9.1
By turning on 0.11, the outdoor blower 4, indoor blower 5, and electromagnetic four-way valve 7 are turned on. 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 input voltage becomes greater than the reference voltage and the comparator 22
is in a Hi output state, the reference voltage (V-) of the comparator 27 of the operating current detection circuit 28 is high, and therefore the MAX control operation is performed with the current detection level being high (Hi).

Further, as the room temperature rises, the capacity of the variable capacity compressor 3 is reduced, and if the room temperature rises even at the lowest capacity, the thermostat 18 is turned to FF.

This state is shown in area B (time chart in Figure 2).

If the outside temperature is higher than a predetermined value, the temperature-sensitive resistance element 1
Since the resistance value of the comparator 22 is small, the comparator 22 outputs the LO signal, and the reference voltage (V
−) is lowered. Therefore, the current detection level of the operating current detection circuit 28 is set to a low (LO) state.

If the setting of the thermostat 18 is changed to raise the room temperature in this state (when the air conditioning load suddenly increases), the variable capacity compressor 3 will control the air conditioning with the capacity (MAx') limited to the current detection level (Lo). The temperature is controlled to a predetermined temperature according to the load. This state is shown by time chart C[ in FIG. Note that region D of the time chart in the same figure shows the condition for starting operation when the outside temperature is high, and control is performed in the same manner as in region C above.

Effects of the Invention As described above, the air conditioner operation control device of the present invention uses the outside air temperature detection means to reduce the set value of the operating current detection means when the outside temperature is higher than a predetermined temperature. Preventing pressure rise in the refrigeration cycle and discharge gas temperature during heating operation, guarantees the life of the variable capacity compressor, and prevents impark transistor overheating and overcurrent trip to ensure smooth and comfortable heating operation. can be done. Furthermore, it has many advantages, such as saving power and making 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. 1... Control circuit, 2... Impark,
3... variable capacity compressor, 8... current transformer, 1
2... Outdoor heat exchanger, exchanger, 13... Indoor heat exchanger, 14... Capillary tube, 15
...Microcomputer, 19...Temperature-sensitive resistance element, 20...Resistor, 24...
Diode, 23...Outside temperature detection circuit, 26
...Compare Lake, 30, old...cooling/heating changeover switch. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
11 negative also yp times null i / j - 11 microcontroller 1 - data 2 + --- diode 23 - 11 Tatoki 3. L city (Taro circuit 27--Kumparator 30-1-me≧EIi, upper sword switch Fig. 2/--1 control circuit, Fig. 3 2
---Innoguchita, 3-Ability I; J Transformation I Figure 5 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 blower, and is provided with an operating current detection means for the variable capacity compressor and an outside air temperature detection means, and inputs a signal when the outside air temperature reaches a predetermined value or more during heating operation. An operation control device for an air conditioner, further comprising a control circuit that lowers a set value of the operating current detection means based on the output of the outside temperature detection means.