JPS6361864A - Operation controller for refrigerator, etc. - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an operation control device for a refrigerator or the like that controls a compressor by switching between a commercial power source and an inverter device to vary its capacity.

BACKGROUND OF THE INVENTION In recent years, in refrigeration equipment such as refrigerators, it has become possible to start and operate the compressor using commercial power and switch to an inverter when necessary to change its cooling capacity. ing.

However, switching between conventional commercial power supply and inverter equipment is
The connection is simply switched by a relay, and no consideration is given to the voltage phase or current phase between the commercial power source and the inverter device, the switching timing of the relay, and the chattering of the relay.

Problems to be Solved by the Invention However, in the above-mentioned conventional method, the relay is switched even when current is flowing, and chatter occurs in the relay contacts at the time of switching. This has the drawback of inducing high voltage at the contacts of the relay, adversely affecting the life of the relay contacts, destroying the elements of the inverter device, and generating noise.

Means for Solving the Problems In order to solve the above problems, the operation control device for a refrigerator, etc. of the present invention includes a switching means for switching the compressor to be driven by either a commercial power supply or an inverter device; The switching means is equipped with a control circuit that switches the switching means at a point where the voltage or current of the commercial power source becomes zero, and delays the inverter device by half a cycle to start the inverter device at the zero cross point and synchronizes it with the frequency and phase of the commercial power source at the time of starting. be.

Effect of the Invention The present invention, with the above-described configuration, eliminates the above-mentioned drawbacks and can smoothly switch the operation between the commercial power source of the compressor and the inverter device, and furthermore, can switch the compressor operation with the minimum amount of time using only the switching means. This can be achieved by configuration.

Embodiment Hereinafter, an operation control device for a refrigerator or the like according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of an operation control device for a refrigerator or the like in one embodiment of the present invention. The refrigeration cycle part has been omitted to simplify the explanation. In FIG. 1, 1 is a commercial power source. Reference numeral 2 denotes a compressor, which is connected to the commercial power source 1 via a switching means 3 when the compressor 2 is started up and during normal operation. 4 is an inverter device connected to the other terminal of the switching means 3. 5 is a temperature detector that detects the temperature inside the refrigerator, etc.
Comparator e compares the temperature with the set temperature and sends a signal. 7 is a switch which is operated when it is desired to rapidly cool down the inside of a refrigerator or the like.

8 is a zero cross detection circuit that detects the point where the voltage of the commercial power supply 1 becomes zero volts and sends out a signal. 9 is a control circuit, which includes a comparator 6 for internal temperature and a switch 7 for rapid cooling.
and zero-cross detection circuit 8 as inputs, and is connected to inverter device 4 and switching means 3 so as to output control signals.

The operation of the operation control device for a refrigerator or the like configured as described above will be described below with reference to FIGS. 1 to 3.

FIG. 2 shows a control circuit 9 in one embodiment of the present invention shown in FIG.
FIG. 3 shows a timing diagram when switching from the commercial power supply 1 to the output of the inverter device 4 in the configuration of FIG. 1.

In the figure, when the compressor 2 of a refrigerator or the like is started up or in normal operation, a signal is sent from the control circuit 9 to the switching means 3 and connected to the commercial power source 1 side, so that the compressor 2 is operated by the commercial power source 1. When the inside of the refrigerator is cooled down to below the set temperature, a signal is sent from the comparator 6 to the control circuit 9, and the starting circuit 10 of the control circuit 9 sends a stop signal to the inverter device 4 to stop the inverter device 4 and switch output. By operating the switching means 3 in the circuit 11 and switching to the inverter device 4 side, the compressor 2
to stop. Next, when the temperature inside the refrigerator rises, the operation returns to the normal operation described above, and normally the commercial power supply 1 is used to switch the switching means 3.
The compressor 2 is operated at 0N10FF to keep the inside of the refrigerator at a constant temperature.

Next, when the temperature inside the refrigerator rises abnormally, when the comparator 6 exceeds a predetermined upper limit temperature setting value, an abnormal temperature rise signal is sent to the control circuit 9. The control circuit 9 receives this temperature rise signal and first detects the output of the zero cross detection circuit 8 in FIG.
The synchronization setting circuit 12 detects the zero cross point shown in FIG. Next, the control circuit 9
By detecting the rise of the zero-crossing point of the zero-crossing detection circuit 8 with the rising edge detection circuit 13 and operating the switching output circuit 11, the switching means 3 is activated at the point shown in FIG.
make it work. At the next zero cross point, the fall of the output of the zero cross detection circuit 8 is detected by the fall detection circuit 14, and by sending a signal to the starting circuit 10, the inverter device 4 is caused to fall from zero volts at the operating frequency at this output timing. Start with the synchronous operation waveform. As a result, as shown in Fig. 3e, the switching means 3 switches the voltage applied to the compressor 2 at zero volts from the commercial power supply 1, and after half a cycle, the switching waveform of the inverter device 4 is supplied at zero volts and in synchronous phase. becomes. Inverter device 4
After switching to , the compressor 2 is operated at high speed by operating the inverter device 4 at a high frequency, and the inside of the refrigerator is rapidly cooled. When the inside of the refrigerator is cooled and reaches the set temperature, the control circuit 9 receives the output of the comparator 6, stops the inverter device 4, and stops the compressor 2.

Next, when the rapid cooling switch 7 is turned on during normal operation, the procedure for switching from the commercial power source 1 to the drive by the inverter device 4 is the same as when the temperature inside the refrigerator increases. If this switch 7 is turned on while the compressor 2 is stopped, the control circuit 9 switches the switching means 3 to the commercial power supply 1 side, and after starting the compressor 2, the switch 7 is turned on from the commercial power supply 1 to the inverter device 4 in the same way as the above-mentioned procedure. After that, the compressor 2 is operated at high speed to rapidly cool the inside of the refrigerator. After a predetermined period of time has elapsed, the inverter device 4 is stopped by a signal from the control circuit 9, the compressor 2 is stopped, and the rapid cooling operation in the refrigerator is completed.

Note that the zero-cross detection circuit 8 is not limited to the above embodiment, but is assumed to detect the current in one line of the commercial power supply 1, detect the point where the value becomes zero, send out a signal, and control according to the same procedure as in the above embodiment. You may do so.

Furthermore, regarding switching from the inverter device 4 to the commercial power source 1, the operation frequency and phase of the inverter device 4 are synchronized with the commercial power source 1, and the inverter device 4 is stopped and the switching means 3 is switched after half a cycle. It is easily possible with an example.

As described above, according to this embodiment, the compressor 2 is connected to the commercial power supply
and an inverter device 4, the switching device 3 is switched at a point where the voltage or current of the commercial power supply 1 becomes zero, and the inverter device 4 is delayed by half a cycle. By providing a control circuit that synchronizes with the frequency 3 and phase of the commercial power supply at the time of starting, switching from the commercial power supply 1 to the inverter device 4 can be performed by switching the high voltage caused by the motor inductance of the motor 2 to the switching means 3 and the inverter device 4. Since this can be done without inducing the elements (not shown) of the inverter device 4, the switching can be done without damaging the elements of the inverter device 4 and the switching means 3. Furthermore, even when a relay is used as the switching means 3, the chattering period of the relay (approximately 3
~6m5), the inverter device 4 is started (after 8.3ms or 10m5) after the chatter stops without current flowing through the contacts, so the inverter element and relay contacts can be easily handled without damaging the inverter element and the relay contacts as described above. , noise generation during switching can also be reduced. Further, switching from operation using the inverter device 4 to the commercial power source 1 can be similarly smoothly performed.

Furthermore, the configuration of the switching part of the large current circuit through which the current of the compressor 2 flows can be changed to the minimum configuration of only the switching means 3.
Switching between the commercial power source 1 and the inverter device 4 during operation, and high/low speed operation using the 0N10FF of the compressor 2 and the inverter device 4 are possible.

Effects of the Invention As described above, the present invention provides a switching means for switching the compressor to be driven by either a commercial power supply or an inverter device, and a switching means for switching the compressor to be driven by either a commercial power supply or an inverter device, and a switching means for switching the compressor to be driven by either a commercial power supply or an inverter device. Switching from the commercial power source to the inverter device during compressor operation is provided by providing a control circuit that delays the inverter device by half a cycle, starts it at the next zero cross point, and synchronizes it with the frequency and phase of the commercial power source at the time of startup. However, since the current can be applied at zero cross after the switching means is stabilized, switching can be performed without inducing a high voltage due to the inductance of the motor and without damaging the elements of the inverter device and the switching means.

Furthermore, desired control can be achieved with a minimum configuration of only the switching portion of the large current circuit through which the current of the compressor flows and the switching means.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of an operation control device for a refrigerator or the like according to an embodiment of the present invention, FIG. 2 is a functional block diagram of the control circuit of FIG. 1, and FIG. 3 is a timing diagram of the configuration of FIG. 1. be. 1...Commercial power supply, 2...Compressor, 3.
...Switching means, 4...Inverter device,
8... Zero cross detection circuit, 9... Control circuit. /-m-commercial source 2-e! JII Machine 3 - Prevention means 4 - Inverter device 8 - Zero cross detection C] Paths 9 to f control passage Figure 1 3 - Cutting means 4 - Inverter device 8 - Zero cross detection circuit 9 - Control circuit Figure 2

Claims (1)

[Claims] an inverter device that converts the frequency of a commercial power source; a switching device that switches the compressor to be driven by either the inverter device or the commercial power source; and a zero-cross detection that detects a point where the voltage or current of the commercial power source becomes zero. The circuit and the output of this zero-cross detection circuit switch the switching means at the zero-crossing point where the voltage or current of the commercial power supply becomes zero, and also start the inverter device at the next zero-crossing point to determine the frequency and frequency of this inverter device at the time of starting. An operation control device for a refrigerator, etc., including a control circuit that synchronizes the phase with the commercial power source.