JPH0819910B2 - Air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air conditioner, and more particularly to an air conditioner suitable for controlling the capacity of a compressor whose rotation speed can be controlled.

[Background of the Invention]

In a conventional air conditioner, a compressor is provided with a discharge gas temperature detecting thermostat, and is configured to cut off the power supply to the compressor when the discharge gas temperature exceeds a certain value.

However, according to this configuration, although the compressor can be protected, the rise in discharge gas temperature cannot be suppressed, and the operation may be intermittent, especially in an overloaded state.

Japanese Patent Application Laid-Open No. 54-88642 discloses a patent for the purpose of stabilizing the operation, improving the service life, and expanding the operating range by performing so-called compressor capacity control by varying the capacity of the compressor according to the load. There is one described in the official gazette.

According to the publication, an inverter is used as a power source of a driving motor of a compressor, and a pressure detector for continuously detecting the pressure of refrigerant on the suction side and the discharge side of the compressor is provided, and a signal from the pressure detector is provided. According to the above, there is described a technique for varying the output voltage and output frequency of the inverter to perform variable operation or start / stop of the compressor, but it is different from the input means and the capacity control means of the compressor of the present invention. It was

In addition, Japanese Utility Model Laid-Open No. 54-166048 is equipped with a control device for performing a stepwise capacity control of the compressor, and the compressor is operated at the high speed side when the cooling and heating load is large and at the low speed side when the cooling and heating load is small. In an air conditioner in which operation control is performed, a timer is provided in the control device, and only activation is performed to forcibly control the operation of the compressor at a low speed for a predetermined time by the operation of the timer, while the control device includes a compressor. An overload detector for the load on the motor (for example, a switch that operates when the coil temperature of the compressor motor reaches a predetermined temperature) is provided, and the detector is operated to forcibly control the operation of the compressor at low speed. Disclosed is an air conditioner characterized by what it has been done. However, this air conditioner detects overload and switches the compressor to low speed operation, and is not designed to prevent overload.

[Object of the Invention]

The present invention has been made in view of the above-mentioned conventional state of the art, and suppresses an increase in motor coil temperature of a compressor, maintenance of the equipment is made, and provision of an air conditioner capable of continuous air conditioning operation is provided. Its purpose is.

[Outline of Invention]

An air conditioner according to the present invention is an air conditioner comprising a compressor whose rotation speed is controllable and a control circuit which outputs a compression function force signal corresponding to an air conditioning load. A temperature sensor that detects a temperature that is correlated with the coil temperature is provided, and the temperature range of the temperature detected by the temperature sensor is divided in stages, and the higher the temperature range becomes, the lower the temperature range becomes. The maximum permissible rotation speed of the compressor motor corresponding to the temperature detected by the temperature sensor is provided with the upper limit table for storing the maximum permissible rotation speed of the compressor motor set in the above in comparison with the temperature range. The maximum allowable rotation speed read from the table is compared with the compressor rotation speed specified by the compression function force signal, and a signal indicating the smaller rotation speed is output. In which sea urchin constituted the control circuit.

 The concept of developing the present invention will be described below.

In an air conditioner capable of capacity control, the number of revolutions of the compressor motor is increased / decreased according to the air conditioning load determined in relation to the room temperature and the set temperature, and the load fluctuation is reduced by continuously operating the compressor. The main purpose is to improve comfort and save energy, but the compressor must be stopped when the coil temperature of the compressor motor rises abnormally.

The present invention incorporates the following capacity control for such contradictory events, without stopping the compressor, and minimizing load fluctuations.

That is, when the coil temperature of the compressor motor reaches a certain constant value (for example, 112 ° C.), the rotation speed of the compressor motor is changed to
It is suppressed to 82% or less of the maximum speed, and 69%, 51%, 42% of the maximum speed each time a constant value (for example, 2 ° C) rises.
%, 33% or less, the capacity control is performed.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing the configuration of a compression functional force control unit of an air conditioner according to an embodiment of the present invention, and FIG. 2 is a time chart diagram of the compression functional force control.

As shown in FIG. 1, the indoor unit 1 includes an indoor sensor 2 for detecting an indoor temperature, a room temperature setting device 3 for setting a desired room temperature, a room temperature detected by the indoor sensor 2 and a set temperature set by the room temperature setting device 3. And a control circuit 5 for converting the output ΔT of the differential amplifier 4 into a predetermined compression function signal HZR.

Here, the compression function force signal HZR may be considered as a signal for instructing the rotation speed of the compressor motor corresponding to the air conditioning load.

On the other hand, the outdoor unit 6 includes a temperature sensor 7 for detecting a temperature correlated with a coil temperature of a compressor motor in the compressor 9, for example, a discharge gas temperature, a temperature signal of a temperature θ detected by the temperature sensor 7 and the indoor unit. The control circuit 8 for inputting the compression function force signal HZR output from 1 and outputting the compression function force control signal HZO to the compressor 9, and the compressor 9
It consists of

The control circuit 8 stores an upper limit table that defines the upper limit of the compression function force corresponding to the temperature θ.

That is, this upper limit table is a set value indicating what percentage of the maximum rotation speed the rotation speed of the compressor motor is controlled with respect to the temperature θ detected by the temperature sensor 7 that is correlated with the coil temperature of the compressor motor. Table, for example, 82% at 112 ° C, 69% at 114 ° C, 51% at 116 ° C
%, 42% at 118 ° C and 33% at 120 ° C are the upper limits of compressive force.

Next, the operation of controlling the capacity of the compressor of such an air conditioner will be described with reference to FIG. 2 in addition to FIG.

In FIG. 2, the horizontal axis represents time t, and the vertical axis represents the discharge gas temperature correlated with the coil temperature of the compressor motor in FIG. 2 (a), that is, the temperature θ detected by the temperature sensor 7,
In FIG. 2B, the compression function force signal, that is, the rotation speed of the compressor motor is taken.

The solid line in FIG. 2 (a) shows the change in the detected temperature θ, the solid line in FIG. 2 (b) shows the change in the compression function force signal HZR corresponding to the air conditioning load, and the broken line outputs from the control circuit 8. Line showing the change of the compression function force control signal HZO
The alternate long and short dash line is a line indicating the upper limit value HZM of the rotation speed of the compressor motor set in the above-mentioned upper limit table.

When the rotation number (solid line) of the compressor motor related to the compression function force signal HZR corresponding to the air conditioning load is less than or equal to the upper limit value HZM (dashed line), the compression function force control signal HZO output from the control circuit 8 is output. The controlled rotational speed of the compressor motor (broken line) coincides with the HZR line (solid line).

When HZR> HZM, the line of the upper limit value HZM (dashed line) matches the controlled rotation speed (broken line) of the compressor motor.

Specifically, referring to FIG. 2, when θ <θ ₀ ,
The upper limit compression function force is HZ0 ', the upper limit compression function force is HZ0 when θ ₀ ≦ θ <θ ₁ , and the upper limit compression function force is HZ ₄ when θ ≧ θ ₄ .

Further, a differential is provided between θ ′ _{0 to} θ ₀ , θ _{0 to} θ ₁ , ... θ _{3 to} θ ₄ , and when the upper limit capacity is once lowered, θ is one step lower temperature. If it does not fall, the maximum capacity does not rise.

In FIG. 2, initially, the compression function force signal HZR (solid line) output from the indoor unit 1 and the compression function force control signal HZO (broken line) output from the control circuit 8 to the compressor 9 match, When the temperature signal of the detected temperature θ of the temperature sensor 7 rises and becomes θ ₁ <θ <θ ₂ , it is limited to HZ0 ≦ HZ1,
When θ further rises and θ ₂ <θ <θ ₃ , HZ0 = HZ2,
When θ ₃ <θ <θ ₄ , HZ0 = HZ3.

The temperature signal of the detected temperature θ of the temperature sensor 7 decreases and θ ₁
<Θ <θ ₂ to become the Hz0 = HZ2 becomes further theta when descends Hz0 = HZR, and the compressor 9 in the same value as the compression force signal HZR outputted from the indoor unit 1 is operated.

If this is explained using specific numerical values, for example,
Temperature sensor 7 that correlates with the compressor motor coil temperature
When the detected temperature θ is 112 ° C or more, the rotation speed of the compressor motor is controlled to 82% or less of the maximum rotation speed, and when it reaches 114 ° C, it reaches 69%, when it reaches 116 ° C, it reaches 51%, and when it reaches 118 ° C, it reaches 42%. 120 ° C
When it becomes above, it will be controlled to 33% or less.

When the coil temperature of the compressor motor drops,
When θ is 118 ° C or less, the rotation speed of the compressor motor is controlled to 42% or less of the maximum rotation speed, and when 116 ° C, it is 51%, 114%.
69% at ℃, 82% at 112 ℃, below 110 ℃
Controlled below 100%.

As described above, according to the present embodiment, the compression function force can be automatically limited when the coil temperature of the compressor motor rises. Therefore, even when the air conditioner is operated in the overloaded state, the compressor is not overloaded, continuous air conditioning operation is possible, and both energy saving and comfort can be improved.

In addition, in the above-described embodiment, an example of the air conditioner in which one indoor unit is connected to one outdoor unit equipped with a compressor whose rotation speed can be controlled has been described, but the present invention is not limited to this. Instead, it can be applied to an air conditioner in which a plurality of indoor units are connected to one outdoor unit.

Further, the air conditioner is not limited to the separate type in which the indoor unit and the outdoor unit are separated, and is also applicable to an air conditioner in which each device of the refrigeration cycle is integrated into a unit.

Further, although specific numerical examples of the capacity control have been described in the above-mentioned embodiments, it goes without saying that this is merely an example and the present invention is not limited to these numerical values.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent the motor coil temperature of the compressor from becoming an overloaded temperature,
It is possible to provide an air conditioner that can prevent a decrease in motor life and can perform continuous air conditioning operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a compression functional force control unit of an air conditioner according to an embodiment of the present invention, and FIG. 2 is a time chart diagram of the compression functional force control. 2 ... Room temperature sensor, 3 ... Room temperature setting device, 5 ... Control circuit, 7 ...
Temperature sensor, 8 ... Control circuit, 9 ... Compressor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriaki Horiuchi 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Hitachi Shimizu Plant (72) Inventor Naoki Suzuki, 390 Muramatsu, Shimizu City, Shizuoka Hitachi, Ltd. 56) References JP-A-59-132779 (JP, A)

Claims (1)

[Claims] 1. An air conditioner comprising a compressor whose rotation speed can be controlled and a control circuit which outputs a compression function force signal corresponding to an air conditioning load, and is correlated with a coil temperature of a compressor motor of the compressor. A temperature sensor that detects a certain temperature is provided, and the temperature range of the temperature detected by the temperature sensor is divided in stages, and the compression is set so that the higher the temperature range becomes, the lower the temperature range becomes. An upper limit table for storing the maximum permissible rotation speed of the machine motor in comparison with the temperature range is stored, and the maximum permissible rotation speed of the compressor motor corresponding to the temperature detected by the temperature sensor is read from the upper limit table and read. The control speed is controlled so as to compare the maximum allowable rotational speed output with the compressor rotational speed specified by the compression function force signal, and output a signal indicating the smaller rotational speed. An air conditioning apparatus characterized by being configured to.