JPH0223779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to an improvement in an air conditioner whose capacity is varied using a frequency conversion method.

(2) Conventional techniques and their problems Various conventional methods have been developed to save energy in air conditioners. In particular, the injection system, unloader system, pole change system, multi-comp system, etc. are selected as those that make the capacity of the compressor variable and improve the COP (coefficient of performance). Recently, a variable capacity air conditioner using a frequency conversion method has been developed, which provides a large energy saving effect, significantly improves comfort, and allows efficient control. This is achieved by a combination of a high efficiency inverter for the air conditioner and a capacity proportional control compressor.

To explain further, in this type of air conditioner, the operating frequency can be varied within a range of, for example, 30 to 90 Hz.

By the way, air conditioners are required to check their rated capacity and performance under the internal and external temperature and humidity conditions specified by JIS. The measurement standard for the rated capacity of this type of variable capacity air conditioner is defined as the capacity when the setting is such that the maximum capacity can be demonstrated under the following conditions.

Indoor temperature Outdoor temperature Cooling operation: 27°C 35°C Heating operation: 21°C 7°C Therefore, in such an air conditioner with variable compressor rotation speed, the compressor is normally adjusted based on the difference between the room temperature and the set temperature. Since the rotation speed of the compressor is determined, if you directly measure the rated capacity according to JIS, the room temperature setting of the air conditioner will be set to the highest temperature for heating and the lowest temperature for cooling, and the rotation speed of the compressor will be set to the highest temperature for heating and the lowest temperature for cooling. is the maximum ability measurement.

As a result, when measuring the rated capacity according to JIS, the rated capacity = the maximum capacity of the air conditioner.

However, the rated capacity in JIS is used as a standard to determine the standard size of the room in which the air conditioner is installed (for example, a wooden 6-8 tatami room), so as mentioned above, the rated capacity = air When setting the maximum capacity of the harmonizer, even if it is installed in a standard room, there is a risk that the capacity will be insufficient on a midsummer day or when there are many people living in the room. Also, if you install it in a room that is even slightly larger than the standard room,
This results in a lack of ability.

Therefore, in order to match the capacity of the air conditioner with the standard room size based on the rated capacity measurement in JIS, it is necessary to set the compressor rotation speed to the maximum rotation speed of the compressor when measuring the rated capacity in JIS. It is necessary to set the rated rotation speed between the maximum rotation speed and the minimum rotation speed.

(3) Purpose of the invention The present invention has been made with attention to the above circumstances, and its purpose is to set the measurement result of the rated capacity according to JIS to a value between the maximum capacity and the minimum capacity. The purpose of this project is to provide a variable capacity air conditioner that makes it possible to

(4) Embodiment of the Invention An embodiment of the present invention will be described below based on the drawings. In FIG. 1, 1 is an outdoor unit, 2 is an indoor unit, and the outdoor unit 1 includes a rotary compressor 3, an electric motor 4 for driving the compressor, a four-way valve 5,
It has an outdoor heat exchanger 6 and a blower fan 7.
The indoor unit 2 has a pressure reducing device 8, an indoor heat exchanger 9, and a blower fan 10. 11 is a commercial power supply, which is three-phase 200V here. 12 rectifies the three-phase alternating current supplied from the commercial power supply 11;
This is a power supply circuit that generates variable frequency AC, and the variable frequency AC output from this power supply circuit 12 is supplied to the electric motor 4. As a result, the rotation speed of the electric motor 4 is controlled. Reference numeral 16 denotes a control circuit, which includes a "cool"/"warm" switch 17 for switching between cooling operation and heating operation, and a "quick cooling" switch 18 for rapidly cooling the room. Depending on the operation mode set to 17, the four-way valve 5
Switch the position. In addition, the control circuit 16 is “cold”.
The operation mode command set in the "warm" changeover switch 17 is output to the speed command circuit 13, which will be described later.

The speed command circuit 13 includes a room temperature detection element 14,
Room temperature setting device 15 that can set the temperature between 21℃ and 30℃
and a speed setting voltage V _S that determines the output frequency (90Hz to 30Hz) of the power supply circuit 12 that determines the rotation of the motor 4 based on the difference between the room temperature and the set temperature by inputting the heating or cooling command from the control circuit 16. Output to the power supply circuit 12.

The speed setting voltage V _S output from the speed command circuit 13 is determined as follows.

During cooling operation, if the room temperature detected by the room temperature detection element 14 is 28°C or less, the 60Hz, 50
One of the four frequencies of Hz, 40Hz, and 30Hz or the OFF width is selected based on the difference between the room temperature and the set temperature, and the speed setting voltage V _S corresponding to the selected frequency is output. In addition, if the detected room temperature is higher than 28℃, 90Hz, 80Hz in Figure 3A
One of seven frequencies (Hz, 70Hz, 60Hz, 50Hz, 40Hz, 30Hz) or OFF is selected based on the difference between the room temperature and the set temperature, and the speed setting voltage V _S corresponding to the selected frequency is output. be done.

On the other hand, when the operation mode command from the control circuit 16 is heating operation, if the room temperature detected by the room temperature detection element 14 is 20°C or higher, the 70Hz, 60Hz,
5 levels of frequency: 50Hz, 40Hz, 30Hz or OFF
One of them is selected based on the difference between the room temperature and the set temperature, and a speed setting voltage V _S corresponding to the selected frequency is output. In addition, if the room temperature is less than 20℃, 90Hz, 80Hz, 70Hz, 60Hz,
7 levels of frequency: 50Hz, 40PH, 30Hz or OFF
One of them is selected based on the difference between the room temperature and the set temperature, and a speed setting voltage V _S corresponding to the selected frequency is output. This speed command circuit 1
The operation of step 3 will be explained based on the flowchart of FIG.

In other words, at F1, the indoor temperature detected by the room temperature sensor
Read the set temperature TS set on TA and temperature setting device.

At F2, it is determined whether the operation is cooling or heating.

If F3 determines that F2 is in cooling mode,
It is determined whether the indoor temperature detected in F1 is higher or lower than 28°C.

At F4, if the detected temperature at F3 is lower than 28℃, the difference between room temperature TA and set temperature TS (TA - TS)
Calculate.

At F5, the maximum value of the inverter's output frequency is the rated value (60Hz) set between the maximum value (90Hz) and the minimum value (30Hz). Select the frequency to which TS) belongs.

At F6, if the detected temperature at F3 is higher than 28℃, the difference between room temperature TA and set temperature TS (TA
-TS).

At F7, the maximum value of the inverter output frequency is calculated from the above figure 3 A between the maximum value (90Hz) and the minimum value (30Hz) at F4 (TA-TS)
Select the frequency to which it belongs.

If F8 is determined to be heating operation at F2,
Determine whether the indoor temperature detected by F1 is higher or lower than 20℃.

At F9, if the detected temperature at F8 is higher than 20℃, the difference between room temperature TA and set temperature TS (TA - TS)
Calculate.

At F10, the rated value (60Hz) is set between the maximum value (90Hz) and the minimum value (30Hz) of the inverter output frequency.From Figure 4B, the (TA-TS) calculated at F4 belongs to Select frequency.

For F11, if the detected temperature at F8 is lower than 20℃, the difference between room temperature TA and set temperature TS (TA
-TS).

In F12, select the frequency to which (TA-TS) calculated in F11 belongs from the maximum value (90Hz) to the minimum value (30Hz) of the inverter output frequency from FIG. 3B.

At F13, the speed setting voltage V _S corresponding to the frequency selected at F5, F7, F10, and F12 is output to the inverter.

Next, the power supply circuit 12 will be explained based on FIG. 2. This power supply circuit 12 varies the voltage and frequency as a method of supplying power to the electric motor 4 configured as an AC induction motor, and a variable frequency power source for variable speed driving of the electric motor 4 is used. 20 is a rectifier circuit that converts commercial power to direct current, and 21 is a voltage V _dc1 output from the rectifier circuit 20, which is the speed setting voltage from the speed command circuit 13.
This is a chopper circuit that controls the output voltage V _dc2 corresponding to V _S. 22 is the output voltage of the chopper circuit 21
V _dc1 is an inverter circuit that generates a three-phase alternating current voltage V _M with a frequency that is related to the voltage, and 23 is a control instruction circuit that controls the chopper circuit 21 and the inverter circuit 22 . The power supply circuit 12 configured in this manner supplies variable voltage and variable frequency power as described above so that the electric motor 4 can output the torque necessary for variable speed operation of the compressor 3, and is used for heating and cooling operation. It is designed to operate stably within the possible operating range.

That is, the power supply circuit 12 drives the electric motor 4 according to the speed setting voltage V _S from the speed command circuit 13,
Control the rotation speed. The compressor 3 directly connected to the electric motor 4 compresses the refrigerant according to its rotational speed, absorbs heat or heats the refrigerant in the indoor heat exchanger 9, and performs a cooling operation or a heating operation. When the rotational speed of the electric motor 4 is changed, the amount of refrigerant compressed by the compressor 3 changes, so the amount of heat absorbed or the amount of heating in the indoor heat exchanger 9 changes. The cooling capacity or heating capacity will change accordingly. Therefore, the speed setting voltage V _S outputted from the speed command circuit 13 based on the difference between the room temperature and the set temperature controls the rotational speed of the electric motor 4 and the compressor 3 to maintain the room temperature almost constant.

Here, when measuring the JIS rated capacity during cooling operation in the air conditioner of this example, first, the room temperature setting is set to the state with the highest cooling capacity according to the measurement conditions of the JIS rated capacity. The lowest temperature setting of the room temperature setting device 15 is set to 20°C, and the indoor temperature is fixed at 27°C.

When operating in this state, first the speed command circuit 13
is 27°C when the room temperature is below 28°C from the room temperature detection element 14.
.

Then, the difference between the room temperature and the set temperature is calculated as 7°C from 27°C - 20°C, a frequency of 60Hz corresponding to this is selected from FIG. 4A, and a speed setting voltage V _S corresponding to 60Hz is output.

As a result, in the air conditioner of this embodiment, the JIS rated capacity for cooling operation is the capacity of the air conditioner when the compressor is driven at 60 Hz.

Also, even during normal use, if the room temperature is below 28℃, the speed setting voltage V _S will be between 60Hz and 30Hz.
The maximum frequency is controlled to 60Hz, but in this case, the room temperature is 28℃ or less and the indoor cooling load is light.
Since such a large air conditioning capacity is not required, there is no problem in actual use. And the room temperature on a midsummer day is 28℃.
In a higher indoor cooling load state, the speed command circuit 13 operates as shown in FIG. 3A based on the difference between the room temperature and the set temperature.
By selecting a frequency between 90Hz and 30Hz and making effective use of a wide variable range of capacity, you can obtain air conditioning capacity that matches the indoor cooling load and quickly cool the room.

Similarly, when measuring the JIS rated capacity during heating operation, the room temperature setting is set at 30°C, which is the maximum temperature setting of the room temperature setting device 15, and the indoor temperature is fixed at 21°C. Therefore, the speed command circuit 13 is controlled when the room temperature is 20
℃ or higher, calculate the difference between the room temperature and the set temperature by 9℃ from 21℃ - 30℃, select the corresponding frequency of 70Hz from Figure 4B, and set the temperature to 70℃.
Outputs the speed setting voltage V _S corresponding to Hz.

As a result, in the air conditioner of this embodiment, the JIS rated capacity for heating operation is the capacity of the air conditioner when the compressor is driven at 70 Hz.

Therefore, in this embodiment, during cooling operation, the room temperature is
When the temperature is 28℃ or below, including the 27℃ condition that is the measurement condition for the JIS rated capacity, the maximum rotation speed of the compressor is reduced to a predetermined value between the maximum rotation speed and the minimum rotation speed, and the JIS
The rated capacity of can be set to an intermediate value between the maximum capacity and the minimum capacity.

In addition, when the room temperature is 20℃ or higher during normal use, the speed setting voltage V _S is selected from 70Hz to 30Hz, and the maximum frequency is limited to 70Hz. It is in a light condition, does not require a large air conditioning capacity, and poses no problem in actual use. And the room temperature on a midwinter day is 20 degrees Celsius.
When the indoor heating load is heavy, the speed command circuit 13 selects a frequency between 90Hz and 30Hz from FIG. It is possible to obtain air conditioning capacity commensurate with the amount of air conditioning and rapidly heat the room.

The specifications of the air conditioner of this embodiment described above are summarized as follows.

1 Operating range: 30 to 90Hz for both cooling and heating 2 Operating Hz at rated capacity operation: 60Hz for cooling, 70Hz for heating 3 Variable capacity control: The operating Hz is determined based on the temperature difference between the room temperature and the set temperature (3rd Figure A shows variable capacity control for cooling, and Figure B shows variable capacity control for heating).

4. Room temperature adjustment range (adjustment range of the room temperature setting device 15): 21 to 30°C for both cooling and heating. 5. Rated capacity operation command... memorized by a microcomputer, etc.

When cooling: Operates at 60Hz or lower when the indoor temperature is 28℃ or lower.

When heating: Operates at 70Hz or lower when the indoor temperature is 20℃ or higher.

In addition, during the above-mentioned cooling, it is also possible to perform this control after a certain period of time after the room temperature drops to 28 degrees Celsius or less.
During the above-mentioned heating, it is also conceivable to carry out this control after a predetermined period of time when the room temperature reaches 20° C. or higher.

FIG. 6 is a graph showing the relationship between the rotational speed N of the motor of the air conditioner of this embodiment and the air conditioning capacity Q for cooling and heating, respectively. Here Nc is
NH is the compressor rotation speed (60Hz) when measuring the rated capacity of JIS cooling operation, and NH is the compressor rotation speed (70Hz) when measuring the rated capacity of JIS heating operation.

Therefore, the compressor rotation speed variable range during cooling operation of an air conditioner is from NMAX (90Hz) to NMIN (30Hz).
Hz), and the cooling capacity at this time is QCMAX~
Although it is QCMIN, the JIS cooling operation rated capacity is QCT, which is between QCMAX and QCMIN.

In addition, the compressor rotation speed variable range during heating operation is
From NMAX (90Hz) to NMIN (30Hz), the cooling capacity at this time is QHMAX ~ QHMIN, but JIS
The rated capacity for heating operation is this QHMAX and
It is QHT which is between QHMIN.

(5) Effects of the Invention As explained above, according to the present invention, the detected room temperature is used as the rated capacity measurement standard in an air conditioning system in which the air conditioning capacity can be varied between the maximum capacity and the minimum capacity based on the difference between the room temperature and the set temperature. When the temperature is within a predetermined temperature range including We can provide an air conditioner with variable capacity that allows you to

In addition, the control circuit can change the maximum capacity to a predetermined rated capacity between the maximum capacity and the minimum capacity when the room temperature detected during cooling operation is below a predetermined value including the rated capacity measurement reference temperature, and the control circuit can change the maximum capacity to a predetermined rated capacity between the maximum capacity and minimum capacity, and Since the maximum capacity can be changed to a predetermined rated capacity between the maximum capacity and the minimum capacity when the room temperature exceeds a predetermined value including the rated capacity measurement reference temperature, there is no problem in actual use. Enjoy comfortable air conditioning.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a refrigeration cycle and electrical block diagram of an air conditioner, Fig. 2 is a block diagram of a power supply circuit, and Fig. 3 is a diagram showing the air conditioner during cooling operation and B during heating operation. Capacity variable control diagram, respectively.
Figure 4A is a variable capacity control diagram for cooling operation with settings changed differently from Figure 3A, B is a variable capacity control diagram for heating operation with settings changed different from Figure 3B, and Figure 5 is a speed command diagram. The operation flowchart of the circuit, FIG. 6, is a characteristic diagram of the cooling and heating capacity with respect to the rotation speed. 16...Control circuit, 13...Speed command circuit, 12...
Power supply circuit, 4... electric motor, 3... compressor.

Claims (1)

[Claims] 1. A temperature sensor that detects the room temperature and a temperature setting device that sets the temperature in the room, and the room temperature of the air-conditioned room detected by the temperature sensor and the set temperature set in the temperature setting device. In an air conditioner that can vary the air conditioning capacity between the maximum capacity and the minimum capacity based on the difference between An air conditioner characterized by comprising a control circuit that changes the rated capacity to a predetermined rated capacity during the period of time. 2. The control circuit changes the maximum capacity to a predetermined rated capacity between the maximum capacity and the minimum capacity when the temperature detected by the temperature sensor is below a predetermined value including the rated capacity measurement reference temperature during cooling operation. An air conditioner according to claim 1, characterized in that: 3. The control circuit changes the maximum capacity to a predetermined rated capacity between the maximum capacity and the minimum capacity when the temperature detected by the temperature sensor is equal to or higher than a predetermined value including the rated capacity measurement reference temperature during heating operation. An air conditioner according to claim 1, characterized in that: 4. The control circuit changes the maximum capacity to a predetermined rated capacity between the maximum capacity and the minimum capacity after a predetermined period of time after the temperature detected by the temperature sensor reaches a predetermined range that includes the rated capacity measurement reference temperature. An air conditioner according to claim 1, characterized in that: