JPS6166038A - Defrosting control unit of air conditioner - Google Patents

Abstract

PURPOSE:To improve the space heating ability of the air conditioner at the time of a low temperature space heating by detecting the temperature of an outdoor heat exchanger at the time of space heating and controlling the operational frequency of a compressor so that an outdoor heat exchanger does not frosted. CONSTITUTION:At the time of starting the space heating operation, a timer circuit contained in an LS 19 is turned ON, and counts the pulse of the frequency of a frequency oscillator 10 to compare a detected temperature (t) detected from a thermistor 6 with a set temperature T set by a resistor 8. If t>=T, a compressor 1 is operated at a frequency f1 by an output de ice using a power transistor 11, and a timer n becomes n + 1. Thus, counting advances. When the external air temperature is lowered and the outdoor heat exchanger becomes frosting and t<T, the compressor 1 is operated at a low frequency f2 to suppress the ability of the compressor 1 and increase the evaporation pressure. As a result, frost attached to the outdoor heat exchanger is molten.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating operation control device for a frequency-controlled air conditioner, in which the operation Fli+ control device is equipped with a microcomputer.

Structure of a conventional example and its problems FIG. 6 is a refrigeration cycle diagram of a heat pump type air conditioner, which consists of a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an outdoor heat exchanger 4, and the like. During heating, the refrigerant discharged from the compressor 1 passes through the four-way valve 2 as shown by the arrow, radiates heat in the indoor heat exchanger 3, is depressurized in the pressure reducer 5, absorbs heat in the outdoor heat exchanger 4, and is released in all directions. Returns to compressor 1 via valve 2.

During heating, if the outside air temperature is low, the outdoor heat and condensed water condensed in the exchanger 4 will gradually start to form frost on the outdoor heat exchanger 4, so the heating capacity will gradually decrease as shown in Figure 7. However, when the operating time reaches a certain time N after the start of operation, it enters defrosting operation (10 hours) (normally the minimum time for N is about 1 hour).
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Conventionally, the air A3 compressor, which is a heresy to the frequency-controlled compressor, continues to operate at the highest frequency when the outside air temperature is high or the indoor temperature is low. Demonstrates d6 warming ability until frost forms. However, when frost begins to form on the single-stage outdoor heat exchanger 4, the compression ratio is higher than that of an air conditioner equipped with a constant frequency compressor, so if the low pressure is low, the frost will progress extremely quickly. ,
The drawback was that the heating capacity was significantly reduced. Here, the broken line indicates the capacity of an air conditioner equipped with a constant frequency compressor. Moreover, even though the heating operation is in progress, cold air is blown out, which gives a bad feeling, and furthermore, it has the disadvantage that it is easy to enter the defrosting operation.

Purpose of the Invention The present invention solves the conventional drawbacks mentioned in 1. When the outdoor heat exchanger starts to form frost during heating operation, the operating frequency of the compressor is changed so that the frost on the outdoor heat exchanger melts. The purpose of this is to lower the frequency once and raise the frequency again once the frost has melted, thereby improving the heating capacity at low heating temperatures.

Structure of the Invention In order to achieve this object, the present invention detects the temperature of the outdoor heat exchanger with a temperature detection means provided in the outdoor heat exchanger, as shown in FIG. and a transition means for sequentially shifting the operating frequency of the compressor using an electrical signal from the comparing means, and a variable frequency output mode for controlling the operating frequency of the compressor step by step using the electrical signal from the shifting means. Consists of a storage means for storing information and an output means for operating the compressor at a frequency specified by the electrical signal of the storage means, and controls the frequency of the compressor according to the temperature of the outdoor heat exchanger in the case of low-temperature heating conditions, etc. This is what we do.

With this configuration, even when the outside air temperature is low during heating, the outdoor heat exchanger is less likely to be frosted, so that the heating capacity can be improved.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings. Here, since the refrigeration cycle is the same as the conventional example, illustration and explanation will be omitted, and here, the content of compressor frequency control during heating at low temperature will be explained.

In FIG. 1, the control circuit controls the temperature t of the outdoor heat exchanger 4.
a thermistor 6 that detects the detected temperature t, a temperature detection device 7 that converts the detected temperature t into an electrical signal and outputs it, a resistance device 8 that provides an electrical signal of the temperature set value T, and a microcomputer (hereinafter referred to as L).
An oscillator device 10 which provides pulses of a constant frequency to 9 (referred to as SI). A comparison circuit that compares and determines the electric signal from the temperature detection device 7 and the electric signal of the temperature set value T, a timer circuit that provides timing for this comparison, and a frequency oscillator 100 counts the frequency of the compressor 1 in stages. The LSI 9 has a built-in variable frequency output circuit that makes the operating frequency of the compressor 1 variable, and a transition circuit that outputs an electrical signal that sequentially shifts the operating frequency of the compressor 1 based on the electrical signal of the comparison circuit.
The compressor 1 is equipped with an output device using a power transistor 11 that operates the compressor 1 at a frequency specified by an electric signal output from the SI 9, a power supply device 12 that supplies the operating voltage of the compressor 1 to the power transistor 11, and the compressor 1. Here, the relationship between the block diagram shown in FIG. 2 and the control circuit diagram shown in FIG. 1 will be explained. The thermistor 6 serves as a temperature detection means, the resistor 8 serves as a temperature setting value, and the comparison circuit, timer circuit transfer circuit, and variable frequency output circuit built in the LSI 9 serve as comparison means, time measurement means, transfer means, and storage means, respectively. The power transistor 11 corresponds to the output means.

Next, the operation of the control circuit having the above configuration will be explained with reference to FIGS. 3 and 4.

At the start of operation, a timer circuit built into the LSI 9 is turned on, and the detected temperature t detected by the thermistor 6 installed in the outdoor heat exchanger 4 is compared with the set temperature T. If t≧T, the operation I ( The compressor 1 is operated at a high frequency of 11), and the timer becomes n = n + 1 and continues counting. When the outside air temperature decreases and the outdoor heat exchanger 4 begins to frost, it operates at operation mode (operates the compressor 1 at a low frequency f2) to suppress the capacity of the compressor 1 and reduce the evaporation pressure. Thorn it out,
As a result, the frost that has formed on the outdoor heat exchanger is thawed.

The flowchart in FIG. 3 and the time chart in FIG. 4 show the flow of operations to the north.

The time chart in Figure 5 shows two temperature settings (Ti
≦T2), and when the detected temperature t falls below T2, the operating frequency of the compressor is lowered by one step, and conversely, when t exceeds T1, the operating frequency is increased by one step. This is designed to ensure that the maximum heating capacity can be obtained while controlling the temperature of the exchanger 4. The same effect can be obtained even if the operating frequency of the compressor is changed in multiple stages using a plurality of constant temperature settings and time control in this way.

Effects of the Invention As is clear from the above embodiments, the heating operation control device for a frequency-controlled air conditioner according to the present invention detects the temperature of the outdoor heat exchanger during heating, and prevents frost formation on the outdoor heat exchanger. By controlling the operating frequency of the compressor, the range of continuous operation at low temperatures for heating can be expanded, and the heating capacity can be increased rapidly without continuing to operate at the highest frequency even if the outdoor heat exchanger becomes frosted. There is no significant deterioration, so it has a good feeling, and it also has various advantages such as being difficult to enter defrosting operation.

[Brief explanation of drawings]

Fig. 1 is a control circuit diagram of an operation control device equipped with a microcomputer according to the present invention, Fig. 2 is a block diagram expressing the same operation control device as a function realizing means, and Figs. Flow chart and time chart of the control device, FIG. 5 is a time chart related to another embodiment of the present invention (-1) FIG.
Each figure is a heating capacity change diagram at low outside temperature showing a conventional example. 1...Compressor, 4...Outdoor heat exchanger, 6...Therminuta, 7...Temperature detection device, 9...Microcomputer . Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
N Figure 5 Figure 4 Figure 7 LI nr? J 7L++2
ntt3 rLrf4 waiting room Figure 6 Time Leap

Claims (1)

[Claims] A compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger are connected in a ring to constitute a heat pump type refrigeration cycle, and a temperature detection means for detecting the temperature of the outdoor heat exchanger. a comparison means for comparing the electric signal from the temperature detection means with a plurality of temperature settings determined by the time measurement means; inputting the electric signal from the comparison means during heating operation;
A transition means for sequentially shifting the operating frequency of the compressor, a storage means for storing a variable frequency output mode for controlling the operating frequency of the compressor in stages according to the electric signal of the transition means, and specification by the electric signal of the storage means. A defrosting control device for an air conditioner, comprising an output means for operating the compressor at a frequency of .