JPS6334377B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type air conditioner having a capacity control compressor, and its purpose is to improve the start-up of the air conditioner during cooling operation, and to reduce the cooling load and The aim is to efficiently control the capacity of the compressor in response to the heating load.

Recently, methods of controlling the capacity of a compressor have been studied in order to control the capacity of the air conditioner according to the cooling or heating load as a means of saving energy in heat pump type air conditioners. For example, in areas where indoor air conditioning is done using heat pump air conditioners, the cooling load is generally lower than the heating load, so the compressor is operated at low capacity during cooling operation and at high capacity during heating operation. There are some systems that control the heating and cooling capacity of air conditioners to correspond to the load and improve efficiency, especially during cooling operation. However, since the compressor operates at low capacity during cooling operation, The drawback was that it was slow.
In order to overcome this drawback, some systems operate the compressor at high capacity for a predetermined period of time when the compressor is started.
In a control system that always operates at high capacity for a predetermined period of time, when the load at startup is low, the capacity of the air conditioner is too large and the air conditioner is forced to operate at low efficiency.

As shown in Fig. 1, which shows the energy efficiency EER of the air conditioner with respect to the compressor capacity Q, as Q becomes smaller, the EER increases and highly efficient operation is possible. In other words, the efficiency of the air conditioner increases by operating the compressor at a low capacity depending on the load.

The present invention is an improvement on the prior art as described above, and provides an air conditioner that starts up quickly and performs highly efficient control.

FIG. 2 shows an embodiment of the air conditioner of the present invention, which is applied to a separate type air conditioner.

1 is an outdoor unit, 2 is an indoor unit,
The outdoor unit 1 includes a compressor 3, a motor 4 for driving the compressor 3, a cooling/heating switching valve 5, an outdoor heat exchanger 6, an outdoor fan 7 for ventilating the outdoor heat exchanger 6, and a pressure reducing device 8. The indoor unit 2 is provided with an indoor heat exchanger 9, an indoor fan 10 for blowing indoor air through the indoor heat exchanger 9, a room temperature detector 10, and a regulator 11. A heat pump type refrigerant circuit is formed by connecting these compressor 3, heating/cooling switching valve 5, outdoor heat exchanger 6, pressure reducing device 8, indoor heat exchanger 9, etc. with piping, and the indoor heat exchanger 9 absorbs or heats heat. This is done to cool or heat the room. This switching is performed by the heating/cooling switching valve 5. The compressor 3
The capacity of the motor 4 can be controlled by changing the rotational speed of the motor 4. The rotational speed of the motor 4 is controlled by changing the voltage and frequency of its power supply, which are controlled by the control device 12. A is a commercial power supply (here, 3-phase), which is the primary power supply, and the control device 12 has six diodes.
D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , D ₆ and Chi York coil
CH ₁ is rectified by a rectifier circuit B consisting of a capacitor C ₁ and converted into a DC power supply, and a chopper control circuit F drives a transistor Tr of a chopper circuit C using a speed signal generated in a speed signal circuit E.
The voltage of the DC power supply is controlled, smoothed by a chiyoke coil CH ₂ and a capacitor C ₂ , and this adjusted and smoothed DC power is input to the bridge inverter control circuit G to generate a frequency corresponding to the DC voltage. The transistors Tr ₂ , Tr ₃ , and transistors of the bridge inverter circuit D connected to the chopper circuit C
Tr ₄ , Tr ₅ , Tr ₆ , and Tr ₇ are driven to generate three-phase rectangular wave power to supply power to the motor 4 . Transistors Tr ₂ , Tr ₃ , Tr ₄ , Tr ₅ , Tr ₆ , Tr ₇ are connected in parallel with diodes D ₇ , D ₈ , D ₉ , D ₁₀ ,
D ₁₁ and D ₁₂ pass the reverse voltage from the motor 4 when each transistor is turned off, and serve to protect each transistor. H is a cooling/heating switching signal, and the signal is sent to the speed signal circuit E.
and input it to the cooling/heating switching valve 5,
Switch between heating and cooling. I is a starting controller which inputs a starting control signal to the speed signal circuit E.
J is a difference signal generator that generates a difference signal ΔE between the room temperature detector 10 that detects the indoor air temperature and the regulator 11 that commands the set temperature of the room temperature, and inputs it to the speed signal circuit E.

Next, the operation will be explained. During heating operation, the heating/cooling switching valve 5 is set to heating operation by a signal from the heating/cooling switching signal device H, and a heating operation signal is input to the speed signal circuit E. Further, a difference signal ΔE between the indoor air temperature and the set room temperature is input from the difference signal generator J to the speed signal circuit E. Figure 3 shows this difference signal ΔE
The relationship between the speed signal Vs and the speed signal Vs from the speed signal circuit E is shown. That is, during heating operation, the speed signal Vs outputs a value from Vs _L to V _SH in response to a change in the difference signal ΔE. The difference signal ΔE increases as the difference between the set value and the room temperature increases, and on the other hand, the speed signal _{V S} = V _SH constant, and in the region where the difference signal ΔE is small, V _S = V _SL
It is constant or zero and has hysteresis characteristics. This speed signal V _S sets the rotational speed of the motor 4 and the compressor 3, and defines the maximum and minimum speeds to solve mechanical strength noise vibration and efficiency problems, and also to improve the compression due to the hysteresis characteristic. This prevents the machine from starting and stopping frequently. Figure 4 shows _the characteristics of the compression force Q due to changes in the rotational speed of the compressor with respect to the speed signal V _S.
As Q increases, Q increases almost proportionally. Due to these characteristics, at the start of heating operation and during normal operation, the capacity of the compressor 3 increases from the minimum capacity Q _L to the maximum capacity Q _H due to the difference signal ΔE between the room temperature and the room temperature set temperature.
Operation is controlled by the range up to or by stopping the compressor.

Generally, at the time of startup, the difference between the room temperature and the set temperature is large, so the compressor is operated at the maximum capacity Q _H or a capacity close to the maximum capacity Q _H. From then on, the difference between the room temperature and the set temperature, in other words, the load The capacity of the compressor 3 is controlled accordingly. The high-temperature, high-pressure refrigerant discharged from the compressor 3 controlled as described above flows into the indoor heat exchanger 9 via the cooling/heating switching valve 5, radiates heat, heats the room, is depressurized by the pressure reducing device 8, and is expanded outside. It absorbs heat and evaporates in the heat exchanger 6 and returns to the compressor 3 via the cooling/heating switching valve 5.

Next, cooling operation will be explained.

A cooling operation signal is input from the cooling/heating switching signal device H to the cooling/heating switching valve 5, and the cooling/heating switching valve 5 is activated to switch the refrigerant circuit to cooling operation, and the signal is input to the speed signal circuit E. The difference signal generator J detects the difference between the indoor air temperature and the set room temperature, and the difference signal ΔE is input to the speed signal circuit E, as in the heating operation. At this time, the sign of ΔE is opposite to that during heating operation, but the sign is reversed in the speed signal circuit E, and as in heating operation, if the difference signal ΔE between the room temperature and the room temperature set value increases, the speed signal V _S However, in the region where ΔE is large enough, the value of V _SM where the speed signal V _S is lower than V _SH ,
It is controlled to be constant. As a result, the maximum capacity of the compressor 3 during cooling operation becomes the third capacity _QM , which is lower than the maximum capacity _QH during heating operation. In this way, the maximum capacity of the compressor 3 is defined in response to the difference in load during heating operation and cooling operation, thereby improving efficiency during cooling operation. At the start of cooling operation, the speed signal V _S is controlled for a predetermined period of time by a signal from the start controller I so that it can generate a signal up to V _SH which is higher than the maximum value V _SM during normal operation. As a result, the compressor 3 at startup can exhibit its maximum capacity up to the maximum capacity Q _H during the heating operation. As a result, it is possible to control the range from the minimum value Q _L to the maximum value Q _H using the difference signal ΔE between the room temperature and the room temperature set value, and when the load is high, the compressor 3 is operated at the maximum capacity Q _H. Therefore, it is possible to create an air conditioner with very good start-up.If the load at startup is low, the capacity of the compressor 3 will decrease in response to the load, or if the load is even lower. The compressor is stopped and controlled to enable efficient operation. During cooling operation, the refrigerant discharged by the compressor 3 controlled in this manner passes through the cooling/heating switching valve 5, radiates heat and condenses in the outdoor heat exchanger 6, is depressurized and expanded in the pressure reducing device 8, and cools the indoor air in the indoor heat exchanger 9. Then, it returns to the compressor 3 via the cooling/heating switching valve 5.

In the above embodiment, when the cooling operation is started, the compressor 3 is controlled by expanding the control range to the maximum capacity Q _H during the heating operation, but the compressor 3 is controlled by expanding the control range to the maximum capacity Q _H during the _{heating operation .} It may be possible to increase the voltage to an appropriate value that is sufficient for the start-up during startup.
Further, in the above embodiment, the capacity of the compressor was continuously controlled, but if continuous control is not performed, at least the compressor should be stopped, the capacity controlled in three stages of capacity Q _L , capacity Q _M , capacity Q _H , or more. Any device that controls the capacity of a compressor in multiple stages may be used.

As is clear from the above embodiments, the heat pump air conditioner of the present invention includes a compressor whose capacity can be controlled in at least three stages, a cooling/heating switching valve, a heat source side heat exchanger, a pressure reducing device, and a user side heat exchanger. It has a heat pump type refrigerant circuit connected by piping, and a heating/cooling switching signal that activates the cooling/heating switching valve to switch between heating and cooling operation, and a heating/cooling switching signal that operates the compressor from minimum capacity Q _L to maximum capacity Q _H during heating operation. During cooling operation, the control range is from the minimum capacity Q _L to the third capacity Q _M (Q _M
A capacity control circuit that controls the _capacity within _the control range up to <Q _H This system is equipped with a capacity control device consisting of a capacity control signal generator that outputs to a capacity control circuit, and controls the capacity of the compressor in both cooling and heating operation states, and moreover, it controls the capacity of the compressor in both cooling and heating operation states. To provide a heat pump type air conditioner that has a lower maximum capacity and has a capacity commensurate with the load of the heat pump type air conditioner, which is highly efficient with less energy loss and has a good start-up of the air conditioner during cooling operation. be able to.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram showing the relationship between compression function and energy efficiency, Fig. 2 is a circuit diagram of an embodiment of the heat pump type air conditioner of the present invention, and Fig. 3 is a speed signal circuit of the heat pump type air conditioner described above. Characteristic diagram, 4th
The figure is a characteristic diagram showing the relationship between the speed signal and the compression function of the heat pump type air conditioner. 3...Compressor (capacity control compressor), 5...Cooling/heating switching valve, 6...Outdoor heat exchanger (heat source side heat exchanger),
8... Pressure reduction device, 9... Indoor heat exchanger (user side heat exchanger), 12... Control device.

Claims (1)

[Claims] 1. A heat pump refrigerant circuit in which a compressor whose capacity can be controlled in at least three stages, a cooling/heating switching valve, a heat source side heat exchanger, a pressure reducing device, and a user side heat exchanger are connected via piping, A heating/cooling switching signal that operates a switching valve to switch between heating operation and cooling operation, and a minimum capacity Q _L of the compressor during heating operation.
The capacity is controlled within the control range from to the maximum capacity Q _H ,
During cooling operation, the third capacity from the minimum capacity Q _L
A capacity control circuit that controls the capacity within a control range up to Q _M (Q _M < Q _H ), and a third capacity Q _M of the compressor is set to the maximum capacity Q _H for a predetermined period of time when the compressor starts cooling operation.
1. A heat pump type air conditioner equipped with a capacity control device comprising a capacity control signal generating section that outputs a signal to the capacity control circuit to increase the capacity to an appropriate capacity.