JPS5956649A - Air conditioner - Google Patents

Abstract

PURPOSE:To decrease the number of times of interruption of a motor-driven compressor and at the same time contrive to reduce the power consumption by a method wherein the motor-driven compressor is controlled at the minimum speed when detected air conditioning load is within a predetermined range, while being controlled in response to the load in the range from the minimum speed to the maximum speed. CONSTITUTION:During air conditioning drive, both outputs of a room temperature sensor 1 and a target room temperature setter 2 are compared with each other at a temperature deviation sensor 3 in order to obtain the rotational speed of the motor- driven compressor 7 at a speed signal generator 4 in response to the deviation. Furthermore, the level of a temperature deviation signal is compared at an intermittent control signal generator 5, which outputs an operation instruction when the level of the temperature deviation signal is higher than a certain fixed level, while outputs a stop instruction when lower. Said rotational speed signal is sent through a speed control signal comparator-selector 6 to the motor-driven compressor 7 when the operation instruction is generated. Said generator 4 generates a minimum speed signal when the temperature deviation (air conditioning load) lies between loads D1 and D2, while generates a speed signal gradually increasing up to the maximum speed when exceeds the load D2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a compressor for compressing refrigerant, and an air conditioner that drives the compressor to air condition a room, and particularly relates to a control system for a motor for driving the compressor. .

[Background of the invention]

In conventional air conditioners, a constant speed induction motor is often used as the motor for driving the compressor, and the operation and stopping of the motor is controlled according to the difference between the indoor temperature and the target temperature. With this type of control method, the motor frequently starts and stops, a large current flows during startup, shortening the life of the motor, compressor, control equipment, etc., and the room temperature rises and falls significantly between starts and stops. However, since the refrigerant does not flow to the heat exchanger during the period when the electric motor is stopped, there is a drawback that the heat exchanger idles unnecessarily. On the other hand, if the rotation speed of the electric motor is controlled according to the heating and cooling load, and the refrigerant flow rate of the heat exchanger is controlled, the heat exchanger will not play, and the performance of the air training unit 11 will be improved. , low power consumption operation becomes OJ function, and comfortable air conditioning with constant room temperature and small vertical fluctuation can be realized.

Figure 1 d Relationship between the rotation speed of the electric compressor of an air conditioner equipped with a compressor driven by an electric motor whose rotation speed can be controlled (hereinafter referred to as an electric compressor), and the cooling and heating capacity. shows. At a constant rotation speed N1 or higher, the cooling or heating capacity increases as the rotation speed increases, so by controlling the rotation speed of the electric compressor, it is possible to operate the air conditioner according to the heating load while still cooling it. . However, as can be seen from this figure, when the rotation speed of the electric compressor is extremely low, below a certain rotation speed N1-1, the heating capacity is reduced while the cooling capacity is still low, and the power consumption is reduced by operating the air conditioner. It has the disadvantage of being wasted. Moreover, FIG. 2 shows the relationship between the electric compressor rotation speed, cooling scale 1, and heating efficiency.

Here, the cooling or heating efficiency η is defined as 5,
As can be seen from the figure, as the rotation speed decreases from the maximum rotation speed N4, the efficiency improves by 1, but at a constant rotation speed N5 (N
On the contrary, efficiency decreases as it becomes smaller. Therefore, even if the electric compressor is operated at a rotation speed below N2 (Nl incline) that gives the same efficiency as the maximum rotation speed N4, the rotation speed will be the same as that shown in Fig. 3 when the rotation speed of the electric compressor is continuously controlled. As is clear from the relationship with power consumption, this is not a good idea in terms of power consumption.

[Purpose of the invention]

The present invention eliminates the drawbacks of the above-mentioned intermittent control and rotation speed control,
The purpose is to provide an air conditioner that requires less operating power and is more comfortable.

[Summary of the invention]

The basis of the present invention is that the electric compressor is not operated at a rotation speed below N2.

In other words, when the cooling or heating load is above a certain level, the rotation speed of the electric motor for driving the compressor is set to the maximum rotation speed N4.
and the minimum rotation speed N according to the cooling (heating) load,
When the cooling (heating) load is constant and the cooling (warming) load is constant, the cooling (warming)
It is characterized in that it is controlled to operate intermittently between the minimum rotational speed N and a stop depending on the room load. Here, the minimum rotation speed N
shall be selected between N2 and N4, taking into consideration other design conditions and performance conditions of the air conditioner.

According to the implementation of the present invention, when the target controlled by the air conditioner h1, for example, the cooling (heating) load exceeds a certain level, the rotation speed of the compressor driving electric motor is controlled as shown in FIG. First, when the cooling (heating) load is below a certain level, due to the intermittent control of the compressor drive electric motor, a certain level of vertical vibration in the room temperature remains, as shown in Figure 5. , unlike conventional intermittent control, the number of intermittent cycles is extremely reduced, resulting in extremely comfortable air conditioning with a long equipment life. As previously mentioned, since the operating performance within the air conditioner increases to a large rjj, a large amount of operating power can be saved.

[Embodiments of the invention]

Hereinafter, a method for controlling the rotational speed of a motor for driving a compressor in an air conditioner according to the present invention will be explained using examples. FIG. 6 is a block diagram illustrating an embodiment of controlling the room temperature in the air conditioner of the present invention, in which 1 is an indoor temperature detector such as a thermistor, 2 is an indoor target temperature setting device, and 3 is a temperature deviation. A detector, 4 is a speed signal generator, 5 is an intermittent control signal generator, and 6 is a speed control signal comparison and selection device, and is equipped with these to issue an operation stop E command and a rotational speed control command for the electric compressor 7, which will be described later. A control command means 8 for generating is configured. 1 to 3 constitute the ¥ adjustment load detection means 9. Electric compressor 71t-J consists of a compressor section, an electric motor section, and a speed control drive section that receives the above control command and controls the electric motor. Next, the control operation will be explained. First, the indoor temperature detected by the indoor temperature detector 1 is compared with the target temperature set in the indoor target temperature setting device 2 in the temperature deviation detector 3 to determine the temperature deviation corresponding to the air conditioning load, and the speed signal is The generator 4 determines the rotational speed of the electric compressor 7 according to the temperature deviation based on the relationship shown in FIG. 7. Also, the intermittent control signal generator 5 compares the levels of the multiple temperature deviation signals, and if they exceed a certain level as in the -1 vs. old example shown in FIG.
If there is any twisting, a stop command will be issued. The speed control signal comparison selector speed signal output is sent to the electric compressor 7, and the above-mentioned intermittent control (if the output signal of the M generator 5 is a stop command, the speed signal generator 4 is frozen; the dynamic compressor rotation speed signal output is At cut 1~, a stop signal is sent to the electric compressor 7, and in this way, the electric compressor 7 receives the speed control signal comparison selector 6.
It is operated according to the output signal of.

FIG. 7 shows an example of how the speed signal corresponds to the temperature deviation of the speed signal generator 4 in FIG. ] 2, the minimum rotation speed N and maximum rotation speed N
A value between 4 and ■) 2 or less indicates that the minimum number of rotations N is given. In Fig. 7, coordinate points N-)2, N), (
])4. N4) do not necessarily need to be connected in a straight line, and may be connected in a line other than a straight line depending on the operating characteristics and control objectives of the air conditioner.

FIG. 8 shows an example of how the operation command corresponds to the temperature deviation of the intermittent 1■ control signal generator 5 in FIG.
) 2, a run command is issued, and when the temperature deviation gradually decreases to Dl, a stop command is issued at that moment. This indicates that the operation command will be issued the moment D2 is exceeded.

〔Effect of the invention〕

As described above, according to the present invention, the rotational speed of the electric compressor is changed to the minimum speed N or higher for good operating efficiency of the air conditioner, and in an area where the air conditioning load is small, the rotation speed of the electric compressor is changed to the minimum speed N of the 1° dynamic compressor. Since the air conditioner is operated intermittently by starting and stopping, it is possible to extend the life of the air conditioner by increasing its operation rate, improve comfort by reducing the frequency of interruptions, and significantly reduce operating power.

[Brief explanation of the drawing]

Figure 1 is a diagram of the relationship between electric compressor rotation speed and cooling (heating) capacity.
Figure 2 is a diagram of the relationship between electric compressor rotation speed and cooling (heating) efficiency.
Figure 3 is a diagram of the relationship between electric compressor rotation speed, consumption box, and force;
5 and 5 are diagrams showing an example of room temperature control according to the present invention and the conventional method, FIG. 6 is a block diagram illustrating an embodiment of the air conditioner according to the present invention, and FIG. is an example of the correspondence between the temperature deviation of the speed signal generator and the rotation speed of the 5-shaft compressor in Fig. 6, and Fig. 8 is an example of the correspondence between the temperature deviation of the speed signal generator in Fig. An example of the correspondence between the 7 product differences and the operation stop command. ... Speed signal generator, 5... Intermittent control signal generator, 6... Speed control signal ratio axis selector, 7... Electric compressor, 8... Control command means, 9... Empty 1st Figure 51 θ //, Ha, /z
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Continuation of the first page of the first page 0 Inventor: Yasuo Hosoda 800 Tomita, Ohira-cho, Shimoga-gun, Tochigi Prefecture Hitachi, Ltd. Tochigi Factory Procedures Amendment 1982 IIII Hanging Alignment Rumor Romo÷□-di-2 Akira, 9 people f+' 2ki, Fang. Device...j. Pa″
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4 to 6 VC, the speed signal generating means 10 makes a correction. 3. Revise Figure 6 of the drawings as shown in the attached sheet. Above 229

Claims (1)

[Claims] Air conditioning indoors by means of a refrigeration cycle that includes a compressor for compressing refrigerant, an electric motor that drives the compressor, an outdoor heat exchanger, and an indoor heat exchanger;
! , In the summation device, the air conditioning load detection means detects the air conditioning %j and the load, and when the air conditioning load is greater than 1)2, the operation signal, and the idle load is 1) + (', 1) 2 > D+
) When playing a smaller role, a stop Shingetsu is generated to cure the prescribed hysteresis mentioned above ↑11. The intermittent control signal generating means for the motor generates a minimum speed signal for the electric motor when the air conditioning load is between 1)+ and a speed signal generating means for generating a speed signal in which the speed signal of the electric motor does not decrease and increases at a maximum speed change; An air conditioner characterized by being provided with a control command means for supplying a control command to a speed control drive section of the air conditioner.