JPS63251777A - Controller for operation of 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 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.

Conventional technology In recent years, for refrigeration equipment such as refrigerators, for example, Japanese Patent Application Laid-open No. 5
Publication No. 9-178989 and JP-A-59-18192
As shown in Publication No. 6, the compressor is started with commercial power.
It is being considered to be able to change the cooling capacity by switching to an inverter device when necessary.

Problems to be Solved by the Invention However, in the above-mentioned conventional system, when switching the operation of the compressor from the inverter device to the original commercial power source, the output frequency of the inverter device is the same frequency as the commercial power source or the operating frequency. (for example, 5oHz), and switching was performed without considering the power supply phase.

Therefore, in the former case, which switches at the same frequency, even if the phases happen to be synchronized, power is not applied to the compressor motor for a short time at the time of switching, so when the compressor rotation decreases and commercial power is next applied, the power will not be applied to the compressor motor. As shown at the 60 Hz point in Figure 6, a slightly large inrush current flows in the commercial power supply at the work point in Figure 5, which may cause unnecessary beam damage, and the capacity of the switching means that can handle this inrush current must be selected. Therefore, the capacity of the switching means becomes large. Furthermore, when the phases are not synchronized, the phase is 18 as shown in Figure 4.
Because of the 0° deviation, excessive current flows through the compressor motor, causing deterioration of the motor, and excessive current flows through the power supply wiring and switching means, causing adverse effects. In addition, the vibrations applied to the compressor were large at that time, and there was a possibility that not only the compressor would be damaged, but also the cooling system piping would break or leak.

In addition, when switching from the operating frequency (such as 90Hz) to commercial power, the compressor brakes suddenly from high speed to low speed and the motor is not in regeneration mode.
As shown at point z, a large inrush current flows through the commercial power supply, causing problems similar to those described above in mechanical systems such as the switching means, wiring system, and compressor.

Furthermore, when switching the compressor from inverter operation to commercial operation, for example, it is conceivable to stop the compressor and then start it with commercial power, but in this case, if you start it without waiting for the cooling system to stabilize, an overcurrent will flow and the protector will operate. Unfortunately, there was a problem that it took a long time to reboot.

In view of the above-mentioned problems, the present invention suppresses both the current and vibration when switching the operation of the compressor from an inverter device to a commercial power source, and downsizes the switching means. The present invention provides an operation control device.

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 between an inverter device and a commercial power source, and a switch in which the voltage or current of the commercial power source is zero. a zero-crossing detection circuit for detecting a point at which The frequency is set higher than the frequency of the commercial power source.

Effect of the Invention With the above-described configuration, when switching from an inverter device to a commercial power source, the present invention makes it possible to make the output frequency of the inverter higher than the frequency of the commercial power source, match the phase of the power source, and switch at the zero cross point. This suppresses increases in current and vibration during switching, and allows switching without stopping.

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 circuit 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. 2
is a compressor, which is connected to the commercial power source 1 via the 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, and includes bridge-connected diodes D1 to D4, a smoothing capacitor C2, and a bridge-connected transistor 01.
~ Consists of Q4. Reference numeral 6 denotes a switch means arranged between the inverter device 4 and the commercial power supply 1. Reference numeral 6 denotes a temperature detector for detecting the internal temperature of a refrigerator or the like, which compares the temperature with a set temperature by a comparator 7 and sends a signal. 8 is a switch which is operated when it is desired to rapidly cool down the inside of a refrigerator or the like.

9 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. Reference numeral 10 denotes a control circuit, which receives the outputs of the internal temperature comparator 6, rapid cooling switch 7, and zero-cross detection circuit 8 as inputs, and is connected to the inverter device 4 and the switching means 3 so as to output control signals. ing.

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 timing diagram when switching from the commercial power supply 1 to the inverter device 4 output in the configuration of FIG. 1. FIG. 3 shows a timing chart showing changes over time in the frequency input to the compressor 2 in the configuration of FIG. In FIG. 1, 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 to operate the compressor 2 with 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 7 to the control circuit 10, and the control circuit 1o switches the switching means 3 to the inverter device 4 side, thereby stopping the compressor 2. Next, when the temperature inside the refrigerator rises, the operation returns to the normal operation described above, and the compressor 2 is normally operated at 0N10FF using the commercial power supply 1 and the switching means 3 to maintain the temperature inside the refrigerator at a constant temperature. Further, during normal operation, the switch means 5 is OFF and the inverter device 4 is not energized.

Next, when the temperature inside the refrigerator rises abnormally, when the comparator 7 exceeds a predetermined upper limit temperature setting value, an abnormal temperature rise signal is sent to the control circuit 10vC. The control circuit 1o receives this temperature rise signal, first sends a signal to the switch means 6 using the output of the zero cross detection circuit 9 to turn it on, and then sends a signal to the switching means 3 at the subsequent zero cross point to turn on the switching means 3.
After switching to the inverter device 4 side, the inverter device 4
K.

The compressor 2 is operated by the inverter device 4 by sending drive signals of the transistors Q1 to Q4 at a predetermined frequency. After switching to the inverter device 4, the inverter device 4 is operated at a high frequency to operate the compressor 2 at high speed, thereby rapidly cooling the inside of the refrigerator.

Next, when the inside of the refrigerator is cooled and reaches the set temperature, the control circuit 1o receives the change in the output of the comparator 7, stops the inverter device 4, and further turns off the switch means 5.
Compressor 2 is stopped.

Next, when the rapid cooling switch 8 is turned on during normal operation, the switching from the commercial power source 1 to the inverter device 4 is the same as when the temperature inside the refrigerator rises. If this switch 8 is turned on while the compressor 2 is stopped, the control circuit 10 switches the switching means 3 to the commercial power supply 1 side and starts the compressor, and then turns on the switch means 6 in the same way as the above procedure, The power supply 1 is switched to drive by the inverter device 4, and then 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.

Next, an explanation will be given of the operation when the rapid cooling switch 8 is turned on during normal operation and the rapid cooling is immediately canceled (the switch 8 is turned on again).

As shown in FIG. 3, the compressor 2 is driven by the inverter device 4 at a frequency f3 until time t. When the rapid cooling switch 8 is pressed at time t, the transistors Q1 to Q4 are connected from the control circuit 10 to the inverter device 4.
When the driving frequency signal is gradually lowered and reaches a frequency f2 (for example, 61 Hz) higher than the frequency f1 (for example, 60 Hz) of the commercial power supply 1, the control circuit 1o is reached at point A as shown in FIG. reaches a predetermined frequency f2.

The control circuit 10 detects the rise of the output of the zero cross detection circuit 9 after point A, and detects the rise of the output of the zero cross detection circuit 9 after point A, and
If the above rising signal falls within the predetermined range (phase range where the rising zero cross occurs) of the signal that drives 1 to Q4, -WE
2 [iS! At the same time, the drive signal of the inverter device 4 is stopped.

Furthermore, there is a delay operation of the switching means 3 itself, and after a delay of time TA, the switching of the switching means 3 is completed at point C, and the connection is made to the commercial power source 1 side. Therefore, the switching means 3 starts switching at the voltage zero-crossing point (four points) of the inverter device 4, and after the TA waiting time, the switching of the phase-synchronized commercial power supply 1 VC is completed (point C). When the load of the motor 2 and the motor L is turned off, that is, when switching starts, the voltage becomes zero cross, and the spark generated at the contact point of the switching means 3 is extremely small. Therefore, after t2 (point C) in FIG. 3, the commercial power supply 1 is used for operation.

As described above, according to this embodiment, the compressor 2 is connected to the commercial power supply
and an inverter device 4, a zero-cross detection circuit 9 detects the point at which the voltage or current of the commercial power supply 1 becomes zero, and a signal from the zero-cross detection circuit 9. A control means 10 for controlling the switching means 3 is provided so that the output frequency of the inverter device 4 is made higher than the frequency of the commercial power source 1 when the operation of the compressor 2 is switched from the inverter device 4 to the commercial power source 1 VC. Therefore, even if power is not applied to the compressor motor for a short time during switching and the rotation of the compressor 2 decreases, the original rotation speed of the inverter device 4 is still high, so when switching to the commercial power supply 1, the rotation speed of the compressor 2 decreases. In addition, inrush current can be reduced, the capacity of the switching means 3 can be minimized, and unnecessary radiation of radio waves can be prevented.

In addition, since the operating frequency of the inverter device 4 (such as 90Hz) is not suddenly switched to the commercial power source 1, the speed of the compressor 2 is not suddenly lowered, and the power supply wiring, switching means 3, and mechanism of the compressor 2 are not changed suddenly. No inrush current or shock is applied to the system, and reliability can be improved with minimum capacity.

Furthermore, since the phases are synchronized and the switching is performed at the zero cross point, no contact surge or inrush current flows in the switching means 3, so that the switching means 3 can be made with a small capacity and its reliability can be improved. Furthermore, the reliability of the compressor 2 motor and power supply wiring can be improved.

In addition, even if the quick freezing suit 8 is turned on or off in the middle of the day, the inverter device 4 can be switched to the commercial power source 1 without stopping the compressor 2, so you can wait for a reboot in the middle of the day. The temperature inside the refrigerator does not rise even in the case of the above mischievous operation, and the quality of the refrigerator can be ensured.

Note that the zero-cross detection circuit 9 is not limited to the above-mentioned 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 in the same procedure as in the above-mentioned embodiment. It's okay.

Furthermore, in the above embodiment, a case has been described in which the compressor 2 is operated at high rotation speed, but when the cooling capacity is not required, such as when the outside temperature is low, the compressor 2 may be operated at low rotation speed to reduce power consumption. Good too.

Effects of the Invention As described above, the present invention provides a switching means for switching a compressor to be driven by either a commercial power source or an inverter device, and a zero-cross detection device for detecting a point where the voltage or current of the commercial power source becomes zero. A circuit and a control means for controlling the switching means according to the signal from the zero-crossing detection circuit are provided so that when switching from the inverter to commercial power, the output frequency of the inverter is higher than the frequency of the commercial power. Sometimes, power is not applied to the compressor motor for a short period of time, causing the compressor rotation to drop and the original rotation speed of the inverter to operate to be high. The capacity of the switching means can be minimized, and unnecessary radiation of radio waves can be prevented.

Furthermore, since the phases are synchronized and switching is performed at the zero cross point, inrush current caused by contact sparks does not flow through the switching means, so the switching means can be made with a small capacity and reliability can be improved. Furthermore, the reliability of the compressor motor and power supply wiring can be improved.

[Brief explanation of drawings]

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 timing diagram for the configuration shown in Fig. 1, and Fig. 3 shows changes over time in the input frequency of the compressor. A timing diagram, FIG. 4 is a characteristic diagram of voltage and current at the time of switching, and FIG. 5 is a characteristic diagram of switching frequency and current. 1...Commercial power supply, 2...Compressor, 3.
...Switching means, 4...Inverter device,
9...Zero cross detection circuit, 1o...
control means. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure I Donkey Figure 3 t + t2 Bay tatami mi y! Figure 4 Figure 5

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 point where the voltage or current of the commercial power source becomes zero. a zero-crossing detection circuit; and a control means for controlling the switching means using a signal from the zero-crossing detection circuit, the output frequency of the inverter device being higher than the frequency of the commercial power source when switching from the inverter device to the commercial power source. An operation control device for a refrigerator, etc.