JPS61237952A - Heat pump type air conditioner - Google Patents

Abstract

PURPOSE:To determine a frequency through a simple and inexpensive controlling method and perform favorable operation control, by providing a pressure- detecting circuit, a frequency-controlling circuit controlled by an output from a comparing circuit in a room, an inverter for performing control according to an output from the frequency-controlling circuit, and a compressor connected to the inverter. CONSTITUTION:Digital signals emitted by the functions of a temperature- detecting circuit 28 and a temperature set point emitting circuit 29 are sent to a comparing circuit 30, where room temperature and a room temperature set point are compared with each other, a signal corresponding to the temperature difference is sent from a room controlling circuit 27 to an exterior controlling circuit 32 through a room-exterior connecting line 31. On the exterior side, an output from the pressure-detecting circuit 33 which outputs a digital signal by turning ON and OFF of a pressure switch 36 and an output from the circuit 27 are inputted to the frequency-controlling circuit 34. The inverter 35 controlled by an output from the circuit 34 outputs a signal to the compressor 18 through a connecting line 37, thereby controlling the compressor 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to frequency control of a heat pump air conditioner equipped with an inverter-controlled compressor.

BACKGROUND ART Conventionally, a heat pump type air conditioner equipped with an inverter compressor has a circuit configuration as shown in FIGS. 4 and 5. Figure 4 shows a refrigerant circuit, in which 1 is a compressor controlled by an inverter, 3 is an outdoor heat exchanger connected to the compressor 1 via a west valve 2, 6 is an expansion mechanism for heating and cooling, An indoor heat exchanger is connected to the exchanger 3, 6 is an accumulator, 7 is a temperature sensor provided at the suction port of the indoor unit 8 to detect the indoor suction temperature, and 9 is an outdoor unit.

In such a refrigerant circuit, control as shown in FIG. 6 has been performed.

The indoor unit control circuit 1o includes a temperature detection circuit 11 connected to the temperature sensor 7, a set temperature transmitting circuit 12 through which the occupant sets the room temperature, and a temperature detecting circuit 11 and a set temperature transmitting circuit 12. (The position of the temperature setting knob is 30'C to 16°C) The digital signal is sent to the comparison circuit 13, which compares the indoor temperature and the indoor set temperature, and sends a signal corresponding to the temperature difference. Indoor/outdoor connection line 14
Then, input the signal from the indoor control circuit 1o to the frequency determination circuit 16 of the outdoor control circuit 15, and switch the inverter 17 so that the frequency corresponds to this signal.
The compressor 1 was controlled by the three-phase AC power output from the inverter 17.

Problems to be Solved by the Invention As described above, the conventional configuration controls the frequency of the compressor 1 and the indoor temperature using only indoor factors such as the temperature sensor 7 and the set temperature oscillation circuit 12. there were.

However, even at the same frequency, the pressure on the high pressure side of the compressor 1 is influenced by the temperature around the outdoor heat exchanger 3.

In other words, the pressure on the high-pressure side of the compressor 1 will be affected by the outdoor temperature. For example, during heating, when the room temperature is low and the outdoor temperature is high, the pressure on the high-pressure side of the compressor 1 will be affected by the high outdoor temperature. Even though the temperature is high, the frequency of compressor 1 is not high because the room temperature is low.
The pressure on the high-pressure side of the unit increases, resulting in an overload condition.
The protection device for compressor 1 was activated, and proper control could not be performed.

The present invention solves these problems and is simple and
Another object of the present invention is to determine the frequency using an inexpensive control method and perform good operation control.

Means for Solving the Problem In order to solve this problem, the present invention includes a temperature detection circuit that detects an indoor temperature thermistor, a set temperature signal circuit, and an output from the temperature detection circuit and the set temperature transmission circuit. The indoor control circuit has a comparison circuit that compares the temperature and oscillates a signal corresponding to the temperature difference, and a pressure detection circuit that outputs a digital signal by turning on and off a pressure switch installed on the high pressure side of the heat pump refrigeration cycle. , a pressure detection circuit, a frequency control circuit controlled by the output from the indoor comparison circuit, an inverter controlled by the output from the frequency control circuit, and a compressor connected to the inverter.

Operation With this configuration and control circuit, the frequency is controlled by the difference between the room temperature and the set temperature and the ON/OFF state of the pressure switch.

EXAMPLE Hereinafter, an example according to the present invention will be explained based on FIGS. 1 to 3. In FIG. 1, 18 is a compressor controlled by an inverter, 20 is an outdoor heat exchanger connected to the compressor 18 via a four-way valve 19, and 22 is an outdoor heat exchanger 2o connected to the compressor 18 via a cooling/heating expansion mechanism 21. 23 is an accumulator, 24 is a temperature sensor provided at the suction port of the indoor unit 2ε and detects the indoor suction temperature, 36 is provided between the compressor 18 and the four-way valve 19,
A pressure switch 26 for detecting high pressure is an outdoor unit. In such a refrigerant circuit, its control is as shown in FIG.

In the indoor unit control circuit 27, a temperature detection circuit 28 connected to the temperature sensor 24, a set temperature transmitting circuit 29 through which the occupant sets the room temperature, and a digital signal transmitted from the temperature detecting circuit 28 and the set temperature transmitting circuit 29. However, comparison circuit 3
0, and a comparison circuit 30 compares the indoor temperature and the indoor set temperature.
The signal corresponding to the temperature difference is sent to the indoor/outdoor communication line 3.
1, the signal is sent from the indoor control circuit 27 to the outdoor control circuit 32. On the outside of the room, the output from the pressure detection circuit 33 that outputs a digital signal depending on the ON/OFF of the pressure switch 36 and the output from the indoor control circuit 27 are connected to the frequency control circuit 3.
Enter 4. Reference numeral 35 denotes an inverter that performs inverter control based on the output from the frequency control circuit 34. The inverter 36 outputs the output to the compressor 18 via a connecting line 37 to control the compressor 18.

In the above configuration, for example, if a stepwise frequency pattern as shown in FIG. Comparison circuit 3
For example, when the indoor temperature and the set temperature difference between the indoor temperature and the indoor temperature are very large (the temperature in the room is low), a D signal is output to the outdoor control circuit 32. At the time of this D signal, at startup or when the outside temperature is low and the pressure of the refrigerant discharged from the compressor 18 is low, the ON/OFF signal of the pressure switch 36 is OFF, and the pressure detection circuit 33 The OFF signal enters the frequency control circuit 34, and based on the pattern shown in FIG. 3, the frequency control circuit 34 determines h- and outputs it to the inverter 35. Operates on output. For this pattern, the frequencies are a) h, b Hz 10 Hz, d
) h will increase in order, eHz 1fHz, q) hllll
l) It will be operated at a high frequency of h. Further, for example, in the case of a D signal, the motor is operated at a frequency of dH, (hh).

In other words, even though the setter wants the temperature to be high, the indoor temperature is low, and the compressor must not be operated at a high frequency due to the low temperature at startup or the outside temperature.
Since the temperature does not approach the set temperature quickly, a pattern is determined to operate at the highest frequency h1.

Conversely, when the outdoor temperature is high or the indoor temperature is low, the pressure of the refrigerant discharged from the compressor 18 increases depending on the outdoor temperature.
The pressure switch 36 is turned on and the frequency is dHz 1
cHz, b) h 2 MHz to prevent abnormalities due to overload.

Effects of the Invention As described above, according to the heat pump type air conditioner of the present invention, the compressor does not have to be controlled depending on the outdoor temperature, and the control according to the indoor temperature and set temperature can be performed quickly. It is.

[Brief explanation of drawings]

Fig. 1 is a diagram of a heat pump type refrigeration cycle according to an embodiment of the present invention, Fig. 2 is a block diagram of the frequency control circuit, Fig. 3 is a diagram of the frequency pattern, and Fig. 4 is a heat pump type refrigeration cycle for explaining a conventional example. FIG. 6 is a block diagram of the conventional frequency control circuit. 18...Compressor, 2o...Outdoor heat exchanger, 21...Air conditioning expansion mechanism, 22...
... Indoor heat exchanger, 23 ... Accumulator, 24- ... Temperature sensor, constant temperature transmitting circuit, 30
...Comparison circuit, 31...Indoor/outdoor communication line, 32...Outdoor control circuit, 33...Pressure detection circuit, 34... Frequency control circuit, 35.
...Inverter, 36...Pressure switch.

Claims (1)

[Claims] Frequency control is controlled by the on/off signal of the pressure switch installed on the high pressure side of the heat pump refrigeration cycle, the digital signal sent from the temperature detection circuit connected to the indoor temperature sensor, and the digital signal oscillated from the indoor set temperature signal circuit. A heat pump air conditioner is equipped with a circuit, an inverter controlled by the output from this frequency control circuit, and a compressor connected to this inverter.