JPS623178A - Air conditioner - Google Patents

Abstract

PURPOSE:To improve the operation efficiency by detecting the case temperature of a compessor or the discharge temperature and restricting the max. revolution speed of the compressor according to the detection temperature, thus permitting the continuous warming operation, suppressing the temperature rise of the compressor. CONSTITUTION:A compressor 1, four-way valve 2, outside-room heat exchanger 3, decompressor 4, and ain interior heat exchanger 5 are allowed to communicate in succession, and a heat pump type refrigeration cycle is constituted. The compressor 1 is driven at variable speed in accordance with the cycle of the output alternating current supplied from an inverter 10. In this case, the output frequency of the inverter 10 is determined by a frequency determining device 13 on the basis of the temperature difference between a room temperature sensor 11 installed at the suction port of the interior heat exchanger 5 and a room-temperature setting device 12. The determined frequency is sent as the frequency instruction (a) into a controller 14. While, the controller 14 restricts the max. frequency according to the detection temperature of a case temperature sensor 15. Therefore, the inverter 10 outputs the frequency corresponding to the instruction of the controller 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an air conditioner equipped with a variable rotation speed compressor.

[Technical background of the invention]

2. Description of the Related Art Conventionally, there is an air conditioner in which the rotational speed of a compressor is operated at a variable speed using an inverter device or the like, and the cooling/heating capacity of the air conditioner can be controlled over a wide range.

As shown in Japanese Patent Application Laid-open No. 58-18046, in this type of air conditioner, the compressor is driven at variable speed depending on the temperature such as room temperature, and the input current of the air conditioner is detected to keep the current within the allowable range of the power supply current. driving .

is configured to do so. Therefore, the upper limit of the compressor rotation speed has been limited by this current value.

Additionally, the compressor case was equipped with a bimetal thermostat, etc., to protect the compressor by stopping power to the compressor if the compressor case temperature rose abnormally.゛ [Problems with conventional technology] However, in the above air conditioner, the room “
If you perform heating operation when the outside temperature is low,
゛The input current is low, so the voltage due to the input current value is low.
'There were cases where the compressor rotational speed was not limited to an upper limit, and operation continued at a high rotational speed. In this case high
・As the rotation speed continues, the temperature of the machine case increases,
The bimetal thermostat was frequently activated. When this bimetal thermostat operates, the compressor cannot be started for a certain period of time, and during this time the user cannot use the air conditioner's heating, causing the room temperature to drop and making it impossible to continue providing comfortable air conditioning.

[Purpose of the invention]

The present invention controls the compressor case temperature within an acceptable range, while
The purpose of the present invention is to provide an air conditioner that can continue heating operation.

[Summary of the invention]

In order to achieve the above object, the present invention includes a temperature detector that detects the case temperature or discharge temperature of the compressor, and a control device that limits the maximum rotation speed of the compressor according to the detected temperature. It is an air conditioner.

[Embodiments of the invention]

An embodiment of the present invention will be described based on FIGS. 1 and 2.

Compressor 1. The four-way valve 2, the outdoor heat exchanger 3, the pressure reducing device 4, and the indoor heat exchanger 5 are sequentially connected to form a heat pump type refrigeration cycle. Further, the outdoor heat exchanger 3 and the indoor heat exchanger 5 are provided with an outdoor fan 6 and an indoor fan 7, respectively.

Compressor 1 is supplied with power from inverter device 10 .

It is driven at variable speed depending on the frequency of the force alternating current. The output frequency of the inverter device 10 is first determined by the frequency determiner 13 based on the temperature difference between the room temperature sensor 11 provided at the indoor heat exchanger suction port and the room temperature setting device 12 arbitrarily set by the user.

The frequency determined by this frequency determiner 13 is sent to the control device 14 as a frequency command a. A compressor case temperature sensor 15 is further connected to the control device 14 . The control device 14 limits the maximum frequency according to the temperature detected by the case temperature sensor 15. The inverter device [10 then outputs a frequency according to the command from the control device 14.

Next, the operation of the control device 14 will be explained based on FIG.

If the compressor case temperature is below 100°C while rising and below 95°C when falling, that is, in zone C in FIG.
14 commands the inverter device 10. In this case, there is no restriction on the maximum frequency (speed).

Next, when the compressor case temperature is 100° C. or higher, that is, in the mu zone, the control device 13 outputs a value obtained by lowering the required frequency of the frequency determiner 13 by a fixed value at fixed time intervals. When the operating state continues for a certain period of time at 9QH2, the command is further decreased by 5H2 and a command of $QH7 is output. This operation reduces the rotational speed of the compressor, allowing operation to continue without the compressor case temperature significantly exceeding 100°C. In addition, the compressor case temperature decreases from over 100°C and falls between 100°C and 95°C (zone C in Figure 2).
In this case, the maximum rotational speed is continued to be limited to the upper limit of the frequency when the temperature is 100°C or less, and the rotational speed is configured so as not to change significantly with 100°C as the boundary. As described above, according to this embodiment, the compressor does not have to be stopped due to an abnormal rise in the compressor case temperature, and the operation can be continued while suppressing the rise in the case temperature, so that the operating efficiency can be significantly improved.

In this example, the maximum rotation speed was limited according to the compressor case temperature, but the same effect can be obtained by restricting the maximum rotation speed according to the compressor discharge temperature, which is approximately proportional to the case temperature. is obtained.

〔Effect of the invention〕

The present invention detects the case temperature or discharge temperature of the compressor,
Since the maximum rotation speed of the compressor was limited according to this temperature,
Pressure! Operation can be continued while suppressing the rise in FM machine temperature, resulting in a significant improvement in operating efficiency.

[Brief explanation of the drawing]

FIG. 1 is an air conditioner according to an embodiment of the present invention, and FIG. 2 is a graph showing changes in compressor case temperature over time to explain the operation of the air conditioner. 1... Compressor 2... Four-way valve 3... Outdoor heat exchanger
4... Pressure reducing device 5;... Indoor heat exchanger 10...
Inverter device 1゜11... Room temperature sensor -2... Room temperature setting device
13... Frequency determiner 14... Control device
□ 15...Compressor case temperature sensor fee: Patent attorney Noriyuki Chika (and 1 other person)
Eda! ! Fight i-ni song

Claims (1)

[Claims] In an air conditioner in which a variable rotation speed compressor, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, etc. are successively connected through cooling piping, a temperature detector for detecting the case temperature or discharge temperature of the compressor; An air conditioner comprising: a control device that limits the maximum rotational speed of the compressor according to the temperature detected by the temperature sensor.