JPS61246537A - Air conditioner - Google Patents

Abstract

PURPOSE:To excellently carry out the control of an indoor side blower at the time of preheating operation and to make it possible to obtain a comfortable space heating operation, by rotating a compressor at a low speed and starting the operation of an indoor side blower when the detected temperature of a heat exchanger becomes greater than the set temperature or when the detected current value exceeds a set current value. CONSTITUTION:When a space heating operation is started, a compressor 31 operates, and a coolant of a high temperature and a high pressure is sent into an indoor side heat exchanger 33. Thus, the indoor side heat exchanger 33 is warmed. Upon this occasion, when the temperature of a temperature sensor 40 of the indoor side heat exchanger 33 is less than the set temperature, an indoor side blower is not operated but the preheating driving is continued. At this time, when the motor of the compressor 31 assumes an overload state and the current value reaches a value I2, a control signal which decreases the rotational speed of the compressor 31 is output from a control circuit 39 to an inverter drive circuit 38, and at the same time, the operation of the indoor side blower 36 is started. As a result, the radiation of the indoor side heat exchanger increases, and the overload condition is released, and the air conditioner continues to operate normally. For this reason, comfortable space heating operation can be carried out.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the control of an air conditioner, and particularly relates to the control of indoor blower operation at the start of heating operation and at the time of restarting heating operation after the end of defrosting operation. It is something.

[Background of the invention]

Generally, a heat pump type air conditioner has a cold air discharge prevention function that operates the indoor fan after the indoor heat exchanger has warmed up at the start of heating operation. Prevention of cold air discharge from a conventional air conditioner will be explained using FIGS. 2 and 3.

In FIG. 2, 31 is a variable capacity rotation speed control compressor, 32 is a four-way switching valve, 33 is an indoor heat exchanger, 34 is a pressure reducing device, and 35 is an outdoor heat exchanger, and these are connected. It consists of a refrigeration cycle.

36 is an indoor fan that blows air to the indoor heat exchanger 33;
37 is an outdoor side blower that blows air to the outdoor side heat exchanger 35. 38 is an inverter drive circuit that drives the compressor 31. 39 is a control circuit for controlling the operation of the air conditioner; 40 is a temperature sensor attached to the indoor heat exchanger 33;
When the temperature exceeds a preset temperature, the control circuit 39 causes the indoor fan 36 to start blowing air. Further, the control circuit 39 controls the temperature sensor 4 after a predetermined period of time has passed after the heating operation.
Even if the temperature of 0 does not reach the set temperature, the indoor fan 3
6, and also has a load reduction function and an overcurrent protection function for the compressor 31, which will be described later.

41 is an operating power source for the air conditioner.

In the above air conditioner, when heating operation is started, the compressor 31 is operated, high temperature and high pressure refrigerant is sent to the indoor heat exchanger 33, and the indoor heat exchanger 33 is warmed. The temperature of the indoor heat exchanger 33 is high (if the temperature sensor 40
When this is sensed, the indoor fan 36 starts operating, and enters a normal heating operation state. If the heating operation is continued, frost will form on the outdoor heat exchanger 35, making it necessary to defrost it. During defrosting operation, the flow of the refrigerant is switched by the four-way switching valve 32, and the high-temperature, high-pressure refrigerant discharged from the positive compressor 31 flows into the outdoor heat exchanger 35 to melt frost. At this time, since the indoor heat exchanger 33 is on the low temperature side, the temperature decreases, and the temperature sensor 40 also becomes low temperature. When the heating operation is restarted after the defrosting is finished, since the temperature sensor 40 is low, the operation of the indoor fan 36 is stopped until the indoor heat exchanger 33 warms up.

When the indoor blower 36 is stopped after the start of heating operation, so-called preheating operation, the high-pressure side blower is stopped, so it is easy to become overloaded, and the load reduction function of the control circuit 39 and the overcurrent protection plate function are not activated. It may work. Here, the load reduction function and overcurrent protection function will be explained using FIG. In the figure, Il is a current that must not be exceeded in order to protect the components of the inverter drive circuit 38, and
When the motor current reaches 11, the operation of the air conditioner is stopped. Here, this function is called an overcurrent protection function. In order to prevent the motor current of the compressor 31 from reaching Il, when I2 reaches I2, the control circuit 39
This is a function that issues a command to the inverter drive circuit 38 to lower the rotation speed of the compressor 31. Here, this function is referred to as a load reduction function. In the figure, when the motor current reaches I2 while the compressor 31 is rotating at the rotational speed Nrrnx during preheating operation, the control circuit 39 controls the rotational speed and N1→
A command is issued to lower the voltage to N2, the motor current is controlled so as not to exceed I2, and the air conditioner continues to operate.

However, rather than the number of rotations decreasing, the motor current increases significantly (as indicated by the broken line in the figure), and when it reaches 11, the operation of the air conditioner is temporarily stopped and the refrigerant pressure in the refrigeration cycle is balanced. Wait and restart after 3 minutes.For this reason,
Conventional control methods do not take into account the fact that if the overcurrent protection function is activated during preheating operation, the heating start-up time will be delayed and comfort will be lost. Also, this kind of thing.

For example, Utility Model Publication No. 46-36299 can be mentioned.

[Purpose of the invention]

An object of the present invention is to provide an air conditioner that improves control of an indoor fan during preheating operation and performs comfortable heating operation.

[Summary of the invention]

That is, in order to achieve the above objective, we have developed a function that starts the operation of the indoor blower based on the current value of the compressor motor during preheating operation at the start of heating operation in an air conditioner using a variable capacity rotation speed controlled compressor. This prevents the air conditioner from shutting down due to overcurrent in the compressor.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIG.

The configuration diagram of the air conditioner is the same as the conventional example shown in FIG. 2. In Figure 1, ■! , I2 is 1 in FIG.
1. Same flow value as Step 2, Nmax %NI N2 is the same rotational speed as Nmax%NIN in FIG.

The operation of the air conditioner of the present invention will be explained. When the heating operation is started, the compressor 31 is operated, high temperature and high pressure refrigerant is sent to the indoor heat exchanger 33, and the indoor heat exchanger 33 is heated. At this time, if the temperature of the temperature sensor 40 attached to the indoor heat exchanger 33 is below a preset temperature, the indoor blower 36 is not operated and the preheating operation is continued. At this time, when an overload condition occurs due to the ambient temperature condition and the current value detected by the motor current value detection means (not shown) of the compressor 31 reaches I2 in FIG. A control signal to lower the rotation speed of the compressor 31 is output to the inverter drive circuit 38, and at the same time, as shown in FIG. 1, the operation of the indoor fan 36 is started. The heat dissipation of the inner heat exchanger increases, the overload condition is released, and the air conditioner continues to operate normally.For this reason, as in the past, the motor current of the compressor 3 increases, causing the air conditioner to It does not have to start or stop (it can perform a comfortable heating operation).

Furthermore, when the indoor blower 36 is operated, the compressor 31
The motor current value must not be exceeded to protect the components of the inverter drive circuit! As long as it is 1 or less, it may be set to 12 or more.

〔Effect of the invention〕

According to the present invention, even if the compressor 31 becomes overloaded and the motor current value increases during preheating operation at the start of heating operation, when the current value reaches a preset value, the indoor blower to reduce the load by driving the
This prevents the air conditioner from shutting down due to overcurrent.
It is possible to provide an air conditioner that can continuously perform comfortable heating operation.

[Brief explanation of drawings]

FIG. 1 is an operational diagram of an air conditioner according to the present invention, FIG. 2 is a block diagram of a conventional air conditioner, and FIG. 3 is an operational diagram. 31... Compressor, 32... Four-way switching valve, 33...
Indoor heat exchanger, 35...Outdoor heat exchanger, 36...
・Indoor blower. B＋″Seki

Claims (1)

[Claims] an indoor blower, a temperature detection means attached to an indoor heat exchanger, a current value detection means for a motor of a rotation speed control compressor, and a control circuit connected to the temperature detection means and the current value detection means; and an inverter drive circuit that inputs a control signal of the control circuit to drive the compressor, and the control circuit controls the temperature detected by the temperature detection means to be lower than a preset temperature after the start of heating operation. or when the current value detected by the current detection means exceeds a preset current value, the compressor is set to low rotation speed and the indoor blower is started to operate. air conditioner.