JPS59170669A - Motor compressour controller for refrigerator, etc. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electric compressor used in a refrigerator or the like, and is intended to save power.

In conventional refrigerators, the capacity control method by changing the applied frequency of the electric compressor was based on internal temperature control, so when the outside temperature is high, the electric compressor operation rate increases, which does not result in power savings, but instead results in the opposite effect. There was a tendency for power consumption to increase.

The present invention relates to control of an electric compressor of a refrigerator or the like in consideration of the above points.

An embodiment of the present invention will be described below with reference to the drawings. First, the characteristics of the electric motor used in the electric compressor will be explained in
This will be explained with reference to FIG.

Figure 1 shows when the refrigerator is installed under three different outside temperatures.
It shows the change in electric compressor input when the frequency applied to the electric compressor of the refrigerator is lowered from the power supply frequency. Here, the relationship between the outside temperatures l, ■, and ■ is I>It>It, and the rate of decrease in input with respect to frequency reduction is hardly affected by the outside temperature.

In addition, Figure 2 shows the change in electric compressor operating time with respect to changes in frequency, and the outside temperature I, ■, and
Each is similar to the figure. As a result, the operating time of the electric compressor increases as the frequency decreases, that is, the cooling capacity decreases. This is greatly influenced by the outside temperature, and the rate of increase is greater when the outside temperature is high.

The third factor is the change in power consumption with respect to the change in frequency.
As shown in the figure. Here, the outside temperatures I, ■, and l are the same as in FIGS. 1 and 2. From this, when the outside temperature is low, 3, , 1, the power consumption decreases as the frequency is reduced, but when the outside temperature is high, the power consumption increases. Outside temperature 1
1 has the characteristic that power consumption is not affected by changes in frequency.

From the above results, we can see that the amount of power consumed does not change depending on the frequency applied to the electric compressor (in this case, the outside temperature ■)
There is an advantage in performing frequency conversion when the outside temperature is lower, but it is more rational not to perform frequency conversion when the outside temperature is higher.

Next, the operation of one embodiment of the present invention will be described.

1 is a thermostat for controlling the temperature inside the refrigerator (not shown), 2 is an electric compressor, 3 is a frequency converter that generates a certain frequency lower than the power supply frequency, and 3a is the above-mentioned Input side of frequency conversion device 3, 3b
is on the output side. Reference numeral 4 is a thermostat for detecting outside temperature, which is installed at a suitable location outside the refrigerator, and is set so that when the temperature drops below a certain level, the contact point connects to 4a, and when the temperature rises above a certain temperature, the contact point switches to 4b. The temperature is the outside temperature ■ described in FIG.

Now, when the refrigerator is installed in a place where the outside temperature is 11 or higher and the power is turned on, the temperature inside the refrigerator is also high, so the thermostano l-1 operates and voltage is applied to the electric compressor 2, but the outside temperature is (2) Since it is -L, the contact point of the type-mostat 4 is switched to 4b, and the applied frequency is equal to the power supply frequency, thereby preventing an increase in power consumption at high outside temperatures.

When the outside temperature drops below ■, the contact point 4a of the outside temperature detection thermostat 4 is switched, and a voltage with a frequency lower than the power wave frequency provided from the output 3b of the frequency converter 3 is applied to the electric compressor 2. This reduces power consumption.

- As is clear from the above embodiments, the present invention includes a thermostat for detecting outside temperature disposed between the thermostat and the electric compressor in a power supply circuit to the electric compressor that includes a thermostat for controlling the temperature inside the refrigerator. By providing a frequency converter for exchanging the frequency supplied to the electric compressor in parallel with the power supply between this outside temperature detection thermostat and the thermostat, the conventional frequency 5 in the refrigerator is increased. With control, the power consumption can be reduced to the same level as before at high outside temperatures, where the amount of power consumed has increased, and since it contributes to power savings only at low outside temperatures, it can be used without being restricted by external conditions. Cost and manufacturing advantages can also be achieved by using only a thermostat as a means of control.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram of the electric motor, Figure 2 is a characteristic diagram of applied frequency and refrigerator electric compressor operating time, Figure 3 is a characteristic diagram of applied frequency and refrigerator power consumption, and Figure 4 is a characteristic diagram of the present invention. It is an electric circuit diagram of the refrigerator which adopted an example. 1...Thermostat, 2...Electric compressor, 3...Frequency converter, 4...Thermo stand for detecting outside temperature. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] A thermostat for detecting outside temperature is disposed between the thermostat and the electric compressor in a power supply circuit to the electric compressor that is controlled by the thermostat that detects the temperature inside the refrigerator,
An electric compressor control device for a refrigerator or the like, comprising a frequency conversion device for converting a frequency supplied to the electric compressor in parallel with a power source between the outside temperature detection thermostat and the thermostat.