JPH01268488A - Controlling method for drive of compressor by two power sources - Google Patents

Abstract

PURPOSE:To prevent an excess current from flowing to a switch and an excess load from being applied to a compressor by switching a switch connected to an AC power source and a switch connected to a DC power source in a no current state, and reducing the output frequency of a power inverter when the current of the switch exceeds a predetermined value. CONSTITUTION:When a DC power source 3 is not started, its state is judged by a controller 11 to close a switch 2. In this case, the output of an AC power source 1 is supplied to an inverter 6 through a power reactor 5. When the power source 3 is started in this state, the inverter 6 is stopped by the controller 11. After the switch 2 is opened, a switch 4 is closed to supply the output of the power source 3 to the inverter 6. On the other hand, when the detected values of current detectors 12, 14, the output frequency of the inverter 6 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for driving a compressor in an air conditioner.

BACKGROUND OF THE INVENTION Conventionally, when operating an air conditioner, it is often driven solely by an AC power source or a DC power source.

Problems to be Solved by the Invention However, the conventional control that is operated using either an AC or DC power source is limited in the power source that can be used and lacks versatility. In addition, there is a problem in that it cannot be applied when an AC power source is used during normal operation and a DC power source is used for emergency operation.

The present invention aims to clarify a method for driving a compressor when there are two power sources for driving an air conditioner, AC and DC.

Means for Solving the Problems In order to solve the above problems, the present invention provides a control device that receives power from an AC power supply and operates, and a first switch connected in series with the AC power supply. , a forward converter for converting alternating current into direct current, an inverse converter for converting direct current to alternating current, a second switch connected between the DC power supply device and the forward converter, and the first switch. a first current detection device that detects current; a first determination device that determines whether the current exceeds a certain value; and a second current detection device that detects the current of the second switch; a second determining device that determines whether the current exceeds a certain value; and a second determining device that determines whether the current exceeds a certain value;
: A control device is provided that turns on the first or second switch based on the output signal of the power source device, thereby selecting the AC power device or the DC power device and converting the power through the inverter. It drives the compressor of the air conditioner.

According to the present invention, even when there are two systems of drive power sources for an air conditioner, AC and DC, switching of the drive power sources is performed smoothly, and an excessive load is not applied to the refrigeration cycle of the air conditioner. can be prevented.゛Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a basic configuration diagram of the present invention, in which 1 is an AC power supply, 2 is a first switch that opens and closes the AC power supply 1, 3 is a DC power supply, and 4 is a DC power supply. This is a second switch that opens and closes the device 3. Reference numeral 5 denotes a forward conversion device for converting alternating current into direct current, the AC input side of which is connected to the output side of the first switch 2, and the DC output connected to the output side of the second switch 4 and the inverse conversion device described below. Connected to 6. 6 is an inverse converter that converts direct current to alternating current, and its alternating current output side is connected to compressor 7.
connected to. The compressor 7 is connected to the heat exchangers 8 and 9 and the expansion valve 10 through refrigerant piping, and as the compressor 7 operates, the refrigerant circulates and heat is exchanged.

Reference numeral 11 denotes a control device, which is directly connected to the AC power supply device 1 without using a switch or the like, and controls the first switch 2, the second switch 4, and the inverter according to the output state of the DC power supply device 3. Control 6. 12 is a first current detection device that detects the current of the first switch 2, and is connected to a first disconnection device 13 that disconnects 1'lJ to determine whether the current exceeds a certain value. . 14 is a second current detection device that detects the current of the second switch 4, and is connected to a second determination device 15 that determines whether the current exceeds a certain value. 1st
The outputs of the determination device 13 and the second 'l'lJ disconnection device 15 are connected to the control device 11.

These situations will be explained with reference to the timing chart in FIG. In the figure, first, the AC power supply device 1 is activated, and the control device 11 starts operating. At this point, the DC power supply 3
If the is not activated, the control device 11 determines its status! The PIJ is disconnected and the first switch 2 is turned on. After the first switch 2 is turned ON and the DC output voltage of the forward converter 5 is stabilized, an inverter drive signal is sent from the control device 11, and an AC voltage is applied to the compressor 7 via the reverse converter 6. , the compressor 7 is operated.

Next, when the DC power supply device 3 is started in this state, the control device 11 turns off this state, stops sending out the inverter drive signal, and stops the operation of the compressor 7. After that, first the first switch 2 is turned on to 0FFj, and then the second switch 4 is turned on. Furthermore, once the compressor 7 is stopped, the pressure in the refrigeration cycle of the air conditioner is maintained for a certain period of time (approximately 2 to 3 minutes) until the pressure is balanced, and then an inverter drive signal is sent and the The compressor 7 is then restarted.

Similarly, when the DC power supply device 3 further stops, the control device 11 determines the state, stops sending out the inverter drive signal, and stops the operation of the compressor 7. After that, first the second switch 4 is turned on to 0FFI, and then the first switch 2 is turned on. Furthermore, once the compressor 7 is stopped, it takes a certain period of time (
After holding the compressor for about 2 to 3 minutes, an inverter drive signal is sent to restart the compressor 7 via the inverter 6.

The same cycle is repeated thereafter.

Pressure Nje! 7, if the air conditioning load increases,
Since the current of the first switch 2 or the second switch 4 increases, this state is detected by the first current detection device 12 or the second current detection device 14, and these current values are kept constant. If the value is exceeded, the first ¥41 cutting device 13 or the second! The I'lJ disconnection device 15 outputs the output to the control device 11, and based on the result, the control device 11 lowers the frequency of the inverter drive signal and lowers the operating speed of the compressor 7, thereby reducing the amount of refrigerant circulation. can be reduced, and operation under overload can be prevented.

As described in detail, the present invention provides a system in which there are two power sources for an air conditioner, AC and DC, with a simple configuration that prevents excessive current from flowing through the switch when switching the power source. Alternatively, it is possible to prevent an excessive voltage from being applied or an excessive load from being applied to the compressor, and it is possible to smoothly switch the power source and operate the compressor.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of a compressor drive device showing one embodiment of the present invention, and FIG. 2 is a timing chart showing the operation of the compressor drive device. DESCRIPTION OF SYMBOLS 1... AC power supply device, 2... First switch, 3... DC power supply device, 4... Second switch, 5. ...Forward conversion device, 6. Song reverse conversion device, 7... Compressor, 11... Control device, 12. Song first current detection device, 13.・・・・・・
・First judgment device, 14... Song second current detection device, 1
5...Second judgment device.

Claims (1)

[Claims] an AC power supply device, a control device that operates upon receiving power from the AC power supply device, a first switch connected in series with the AC power supply device, and a forward conversion device that converts AC to DC; an inverse converter that converts direct current to alternating current; a direct current power supply; the direct current power supply; a second switch connected between the direct current power supply and the forward converter; and the first switch. a first current detection device that detects the current of the second switch; a first determination device that determines whether the current exceeds a certain value; and a second current detection device that detects the current of the second switch. , comprising a second determination device that determines whether the current exceeds a certain value, and a control device that turns on the first or second switch based on the output signal of the DC power supply device. , the control device selects the AC power supply device or the DC power supply device, drives the compressor of the air conditioner via the inversion device, and the current of the first or second switch is controlled. A drive control method for a compressor using two power sources, wherein when the current exceeds a certain value, the output frequency of the inverse converter is reduced until the current falls below a certain value.