JPH0658600A - Controlling method for air conditioner - Google Patents

Abstract

PURPOSE:To contrive cost reduction simplification of the air conditioner by controlling an outdoor unit for the air conditioner by a single microcomputer. CONSTITUTION:An input commercial power source is set to a predetermined constant DC voltage by a power source 20. The constant DC voltage is used as a power source voltage for a switching circuit 23 for a compressor and a switching circuit 24 for a blower. Switching elements of the circuits 23, 24 are turned ON, OFF at a predetermined timing by a microcomputer 32, and an ON signal of the elements of at least one of upper and lower arms of the circuit 24 is chopped by a predetermined frequency. An ON duty ratio by the chopping is variably controlled, DC brushless motors 21, 22 of the compressor and the blower are controlled, and an outdoor unit can be controlled by the microcomputer 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an air conditioner composed of an indoor unit and an outdoor unit, and more specifically, it is possible to share a power supply voltage in the outdoor unit, and the same outdoor unit by one microcomputer. Control
The present invention relates to an air conditioner control method for reducing the cost of outdoor units and making them more compact.

[0002]

[Prior art] Recently, as a fan motor for various home appliances,
DC brushless motors are being used in place of AC motors, and the DC brushless motor control circuit that controls the DC brushless motor is being applied in order to apply the DC brushless motor to various devices and make it easily available. Various proposals have been made.

For example, as shown in FIG. 5, in an outdoor unit of an air conditioner, when a DC brushless motor is used as a motor for an outdoor unit blower, a DC power source for driving the DC motor and a predetermined fixing of the DC brushless motor are fixed. A DC brushless motor control circuit for controlling the DC brushless motor and a switching circuit that supplies a predetermined voltage to the child winding is required. Also, the compressor of the outdoor unit is controlled by an inverter, and the input / output functions required for controlling the outdoor unit are also required. And requires an air conditioner system control microcomputer for controlling the outdoor unit.

In FIG. 5, this outdoor unit includes a DC brushless motor 1 for a blower, a rectifier circuit 3 and a capacitor 3a for rectifying and smoothing an input commercial power source 2, and the rectifier
A voltage conversion circuit 4 (switching power supply) including a transformer 4a, a transistor 4b, a diode 4c and a capacitor 4d for switching the smoothed voltage and smoothing the smoothed voltage, and the smoothed DC voltage. A switching circuit 5 for a blower that supplies a predetermined stator winding (coil) of the DC brushless motor 1, a position detection sensor (for example, a hall element) 6 that detects the position of the rotor of the DC brushless motor 1, and The ON duty ratio of switching of the transistor 4b of the voltage conversion circuit 4 is changed in order to change the DC voltage level supplied to the switching circuit 5 based on the rotation speed information (target rotation speed) of the outdoor unit blower, and The ON / OFF timing of each transistor of the switching circuit 5 should be the same as the above. A DC brushless motor control circuit 7 which determines the position information (position detection signal) of the rotor of the brushless motor 1 and can supply the output voltage of the switching circuit 5 to a predetermined stator winding of the DC brushless motor 1, and Drive for driving each transistor of the switching circuit 5 by a signal from the DC brushless motor control circuit 7 (for example, inverted signals of u, v, w and x, y, z signals shown in FIGS. 7A to 7F). Circuit 8, a motor (AC motor) 9 of a compressor that constitutes a refrigeration cycle of the air conditioner, a rectifier circuit 10a for obtaining a DC power source for driving the motor 9 of the compressor from an input commercial power source 2, a voltage doubler circuit 10b and a smoothing capacitor 10c, etc., and the DC voltage output from the voltage conversion circuit 4 Voltage control circuit 10d for obtaining a power supply voltage of Rashiresumota control circuit 7
And a switching circuit 11 for a compressor for switching a DC voltage output from the power supply circuit to control an inverter of a motor 9 of the compressor, and a DC voltage output from the power supply circuit 10 to a general signal system of the outdoor unit. The voltage control circuit 12 for stepping down to the power supply voltage and the necessary control signals from the indoor unit are input to perform various inputs and outputs necessary for controlling the outdoor unit of the air conditioner to control the outdoor unit and also the above-mentioned rotation speed. In order to output information and to control the inverter motor 9 of the compressor, a PWM signal is output to turn on each transistor of the switching circuit 11.
Air-conditioner system control microcomputer that turns on and off (CP
U) 13 and.

When the DC brushless motor 1 is a three-phase DC brushless motor, the switching circuit 5 is composed of a pnp transistor 5a and an npn transistor 5b, for example, as shown in FIG.

In the rotation control of the DC brushless motor 1, the timings of the inverted signals of u, v, w and the x, y, z signals shown in FIGS. 7A to 7F, that is, the DC brushless motor are controlled. 1 current switching timing is determined by the position detection signal from the position detection sensor 6, and the switching circuit 5 is determined by these signals.
Each of the transistors 5a and 5b is turned on and off.

Further, the voltage conversion circuit 4 is based on the rotation speed information from the microcomputer 13 for controlling the air conditioner system.
Since the ON duty ratio of the transistor 4b is variably controlled, the output DC voltage level of the voltage conversion circuit 4 is varied, and this level-varied DC voltage is supplied to the switching circuit 5.

Further, since the input DC voltage of the switching circuit 5 is supplied to the predetermined stator winding of the DC brushless motor 1 at a predetermined timing based on the position information of the rotor by the position detection sensor 6, the same DC The brushless motor 1 is rotationally controlled, and the DC brushless motor 1 is rotated according to the target rotational speed.

[0009]

However, in the above air conditioner, since it is necessary to change the DC voltage supplied to the predetermined stator winding of the DC brushless motor 1, the DC brushless motor 1 is driven. The power supply for switching (switching power supply), the power supply for driving the compressor, and the power supply for the general signal system (power supply of a constant voltage) such as the DC brushless motor control circuit 7, the microcomputer 13 for controlling the air conditioner system, the actuator, etc., that is, many Since the power supply circuit (complex power supply circuit) must be provided and the DC brushless motor control circuit 7 and the air conditioner system control microcomputer 13 are required as the control device for the outdoor unit, the cost is increased and the outdoor The size of the machine is limited, and the number of revolutions is constant for each target number of revolutions. Speed is a problem that fluctuate.

The present invention has been made in view of the above problems, and an object thereof is to reduce the number of power supply circuits, to control all of the outdoor units with a single microcomputer, and thus to reduce the number of parts. Reduce
An object of the present invention is to provide a control method for an air conditioner, which can reduce the cost and downsize and can keep the rotation speed constant even if the load changes.

[0011]

In order to achieve the above object, the present invention comprises at least an indoor unit and an outdoor unit,
In an air conditioner that controls a compressor that constitutes a refrigeration cycle and that controls an outdoor unit blower, a power supply circuit that inputs an input commercial power supply and outputs a predetermined constant DC voltage,
A DC brushless motor for the blower and a DC brushless motor for the compressor that use a constant DC voltage as a power source, and a blower for driving the DC brushless motor for the blower that allows a constant DC voltage by the power circuit to be input as the power supply voltage. Switching circuit and a compressor switching circuit that drives the DC brushless motor of the compressor, a voltage control circuit that steps down the power supply voltage of the power supply circuit to the general control system power supply voltage of the outdoor unit, and the DC brushless motor of the compressor. In order to rotate at a predetermined number of revolutions, each switching element constituting the switching circuit for the compressor is turned on and off at a predetermined timing, and for the blower, the position information is detected by the position detecting means of the DC brushless motor of the blower. ON the switching elements of the upper and lower arms constituting the switching circuit at a predetermined timing, OF
Based on the rotational speed information (target rotational speed), the ON signal of each switching element of at least one of the upper and lower arms is chopped at a predetermined frequency based on the rotational speed information (target rotational speed), and the ON duty ratio due to this chopping is determined by the position information. A DC brushless motor and a blower for the compressor, which has a control means for variably controlling the obtained current rotation speed and the relevant rotation speed information (target rotation speed) to change the applied voltage of the DC brushless motor for the blower. The DC brushless motor power source and the control system power source of the outdoor unit can be shared, and the control means is included in the microcomputer for controlling the outdoor unit. The same microcomputer controls the outdoor unit of the air conditioner. Has the necessary input / output functions to control the compressor, blower and the outdoor unit. And summarized in that the Noh.

[0012]

With the above structure, the one microcomputer controls the compressor, the DC brushless motor of the blower, and the outdoor unit.

In this case, the power supply voltage (constant DC voltage) from the power supply circuit is input to the switching circuit for the compressor and the switching circuit for the blower, and the constant DC voltage is supplied by the voltage control circuit. It is stepped down to the voltage of the microcomputer and actuator of the outdoor unit.

In controlling the rotation of the DC brushless motor of the blower, each transistor of the switching circuit for the blower is switched based on the position information by the position detection sensor of the DC brushless motor, and the DC voltage is changed to DC by the switching circuit. It is supplied to a predetermined stator winding of a brushless motor. At this time, the number of rotations of the DC brushless motor is calculated from the position information, and the transistors that form at least one of the upper and lower arms of the switching circuit for the blower are calculated based on the calculated rotation speed and the rotation speed information. ON base signal of
Since the time is chopped and the ON duty ratio of the chopping is variably controlled, the rotation speed of the DC brushless motor is matched with the rotation speed information (target rotation speed).

As described above, in the outdoor unit, a single power supply circuit for driving the compressor and the blower is sufficient, and a single microcomputer is used as the control means for the outdoor unit. The power supply system and control system of the machine can be simplified and the number of parts can be reduced.

Further, since the DC brushless motor is controlled to detect the rotation speed of the DC brushless motor so as to reach the target rotation speed, the rotation speed is kept constant at the target rotation speed even if the load varies. Can be

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the air conditioner of the present invention, the motors of the outdoor unit blower and the compressor are both DC brushless motors, and the power source for driving the blower and the compressor can be shared. The general signal system power supply voltage for microcomputers and actuators has been obtained, the power supply circuit of the outdoor unit can be simplified, and all of the outdoor units can be controlled by one microcomputer, and the DC brushless motor of the blower can be controlled. The rotation speed is detected and the control is performed so as to reach the target rotation speed, and the rotation speed is kept constant at the target rotation speed even if the load changes.

Next, one embodiment of the outdoor unit of the air conditioner of the present invention will be described with reference to FIGS. 1 to 4. In the figure, the same parts as those in FIG.

Referring to FIG. 1, in the outdoor unit of this air conditioner, a rectifier circuit 20a for rectifying the input commercial power source 2, a voltage doubler circuit 20b for converting the rectified voltage into a voltage doubler, and this voltage doubled voltage are used. Smoothing circuit 20c for smoothing
DC brushless motors (three-phase DC brushless motors) 21 and 22 are used as the motors of the compressor and the blower in order to share the power supply circuit 20 by the compressor and the blower. , 22 are high voltage type (for example, rated voltage 280 V), and high voltage type transistors (for example, rated voltage) are used as the transistors of the compressor switching circuit 23 and the blower switching circuit 24 that drive the DC brushless motors 21 and 22. 28
0V) is used.

In this outdoor unit, a position detection circuit 25 for detecting the position of the rotor of the DC brushless motor 21 of the compressor, a position detection signal from the position detection sensor 6 of the DC brushless motor 22 of the blower, and a reference. Comparing circuit 26 and amplifying circuit 27 for comparing and outputting the value
A compressor drive circuit 28 for driving each transistor of the compressor switching circuit 23; an upper arm drive circuit 29 for driving each transistor 24a (shown in FIG. 2) of the upper arm 24A of the blower switching circuit 24; Lower arm 2 for switching circuit 24
4B of the lower arm drive circuit 30 for driving each transistor 24b, and for chopping the base signal (when ON) for driving each transistor 24b at a predetermined frequency, and the lower arm drive circuit 30 for chopping the base signal. Drive voltage control circuit 3 for chopping control of power supply
1 and the necessary control signal and position detection circuit 25 from the indoor unit
The output signal from the controller is input, the signal for controlling the compressor is output to the compressor drive circuit 28, and the timings of the base signals are adjusted in the same manner as in the prior art according to the position information from the position detection sensor 6. For example, the inverted signals of u, v, and w and the x, y, and z signals shown in FIGS. 7A to 7F are output to the upper arm drive circuit 29 and the lower arm drive circuit 30, and FIG.
The chopping signal shown in FIG.
To the ON duty ratio of the chopping according to the rotation speed information (target rotation speed), and has an input / output function necessary for controlling the outdoor unit, and controls the actuator of the outdoor unit. And a microcomputer 32 for controlling the outdoor unit.

The operation of the outdoor unit of the air conditioner having the above structure will be described with reference to the switching circuit diagram of FIG. 2 and the time chart diagram of FIG. The outdoor unit operates and the microcomputer 32 of the outdoor unit controls the rotation speed of the outdoor unit blower based on a necessary control signal from the indoor unit side.

In this case, the microcomputer 32
According to the rotation speed information, for example, as shown in FIG.
The chopping signal shown in FIG. 7A is output, and the inverted signals of u, v, and w and x, y shown in FIGS. 7A to 7F are output in accordance with the position detection signal (position information) from the position detection sensor 6. , Z signal is output, while a signal for controlling the compressor at a predetermined rotation speed is output according to the signal from the position detection circuit 25.

The power supply circuit 20 converts the input commercial power supply 2 into a power supply voltage (constant DC voltage) supplied to the compressor switching circuit 23, and the converted constant DC voltage is supplied to the blower switching circuit 24. Is also being supplied.

Further, as in the conventional case, the constant DC voltage output from the power supply circuit 20 is converted by the voltage control circuit 12 into a general signal system power supply voltage such as the microcomputer 32 or a power supply voltage such as an actuator.

Here, in the microcomputer 32, the base signals of the respective transistors 24a and 24b of the blower switching circuit 24 are the position detection sensor 6 as described above.
7A to 7F based on the position information of the above, the signals are output to the upper arm drive circuit 29 and the lower arm drive circuit 30 at the timings shown in FIGS. Further, the chopping signal shown in FIG. 3A is output to the drive voltage control circuit 31,
The lower arm drive circuit 3 is controlled by the drive voltage control circuit 31.
Since the power source of 0 is controlled according to the chopping signal, as shown in FIGS. 3B to 3D, when the base signal driving each transistor 24b of the lower arm 24B is at the "H" level (when ON). ) Is chopped, and O in the period T of the chopping (shown in FIG. 3A) is performed.
The N duty ratio is variably controlled by the microcomputer 32 based on the rotation speed information.

As a result, the output DC voltage of the blower switching circuit 24, that is, the DC voltage (three-phase voltage) supplied to the predetermined stator winding of the DC brushless motor 22 of the blower is variably controlled. The rotation speed information of the DC brushless motor 22 (target rotation speed)
Can be

In the microcomputer 32, a signal for controlling the compressor at a predetermined rotation speed is output to the compressor drive circuit 28 based on a control signal from the indoor unit, an output signal from the position detection circuit 25, and the like. To do.

Each transistor of the compressor switching circuit 23 is turned on and off by a signal from the microcomputer 32, whereby a constant DC voltage output from the power supply circuit 20 is converted into a three-phase voltage for use in the compressor. It is applied to the DC brushless motor 21 and the compressor is controlled.

In this case, the position of the rotor of the DC brushless motor 21 of the compressor is detected by the position detection circuit 25, and this position detection signal is inputted to the microcomputer 32. The timing for turning on and off each transistor of the switching circuit 23, that is, the switching timing of the motor current is determined, and the rotation speed of the compressor DC brushless motor 21 is calculated from the position information. The calculated rotation speed and the target of the compressor. Based on the rotation speed, control is performed to set the compressor to the target rotation speed.

The operation of the microcomputer 32 will be described in detail with reference to the flowchart of FIG. 4. First, it is assumed that the outdoor unit is operating in response to a necessary control signal from the indoor unit of the air conditioner. At this time, the microcomputer 32 performs the input / output control necessary for controlling the outdoor unit of the air conditioner, and controls the outdoor unit.

Then, in the microcomputer 32, in order to control the blower based on the rotation speed information (target rotation speed), the chopping signal shown in FIG. 3A is output through the output port and input. According to the position information input through the port, for example, FIG.
The inverted signals of u, v, w and the x, y, z signals shown in (a) to (f) are output through the output port.

Signals from the output ports of the microcomputer 32 are input to the upper arm drive circuit 29 and the lower arm drive circuit 30, respectively, and the drive voltage control circuit 3 is also provided.
1 performs chopping control of the power supply of the lower arm drive circuit 30 in accordance with the input chopping signal, and therefore the inverted signals of u, v, w shown in FIGS. 7A to 7C from the upper and lower arm drive circuits 29, 30 and 3 (b) to 3 (d)
The x, y, and z signals shown in are output to the transistors 24a and 24b of the switching circuit 24 as base signals (step ST1).

As a result, the DC brushless motor 1 described above is used.
Is rotationally driven. At this time, the current rotation speed of the DC brushless motor 22 of the blower is calculated based on the position information by the position detection sensor 6 (step ST2), and this calculated rotation speed is compared with the target rotation speed. (Step ST
3, ST5).

When the present rotational speed is lower than the target rotational speed, the lower arm 2 of the blower switching circuit 24.
When the base signal of each transistor 24b of 4B is chopped, the chopping ON duty ratio is increased (step ST4), that is, the current drive voltage (three-phase DC voltage) of the DC brushless motor 22 of the blower. Will be raised.

On the other hand, when the current speed is higher than the target speed (step ST5), the transistors 2 are turned on.
Although the chopping is performed when the base signal of 4b is ON, the ON duty ratio of the chopping is reduced (step ST6), that is, the current drive voltage of the DC brushless motor 22 of the blower is lowered.

By repeating steps ST1 to ST6, the rotation speed of the DC brushless motor 22 of the blower is variably controlled to approach the target rotation speed, and the DC brushless motor 22 of the blower is driven at the target rotation speed. .

The microcomputer 32, which drives the DC brushless motor 22 of the blower and controls the rotational speed thereof, also serves as the DC brushless motor control circuit 7 and the air-conditioning system control microcomputer 13 of the conventional example, that is, The DC brushless motor control circuit 7 is omitted.

In this way, the motors of the compressor and the blower are DC brushless motors, and the DC brushless motors 21 and 22 of the compressor and the blower are used.
The power supply voltage (constant DC voltage) supplied to each of the switching circuits 23 and 24 for driving the power supply circuit is obtained by one power supply, that is, the power supply circuit 20, and the constant DC voltage by the power supply circuit 20 is reduced by the voltage control circuit 12. Since the general signal system control power supply voltage of the outdoor unit is obtained as described above, the power supply of the outdoor unit can be reduced.

In other words, the power source for the outdoor unit is 1
Since only a set of power supply circuits is required, the power supply circuit of the indoor unit can be simplified and the number of parts can be reduced, which can further reduce the cost and size of the indoor unit.

Further, since it is possible to use only one microcomputer 32 instead of the DC brushless motor control circuit 7 and the air-conditioning system control microcomputer 13 of the conventional example, the control system of the outdoor unit is simplified and the number of parts is reduced. It is possible to achieve cost reduction and size reduction. Further, since the rotational speed of the DC brushless motor is detected and controlled so as to reach the target rotational speed, the rotational speed can be kept constant at the target rotational speed even if the load changes.

[0041]

As described above, according to the present invention, a control method for an air conditioner, which comprises at least an indoor unit and an outdoor unit, controls a compressor that constitutes a refrigeration cycle, and controls an outdoor unit blower. In, a power supply circuit for inputting an input commercial power supply and outputting a predetermined constant DC voltage,
A DC brushless motor for the blower and a DC brushless motor for the compressor that use a constant DC voltage as a power source, and a blower for driving the DC brushless motor for the blower that allows a constant DC voltage by the power circuit to be input as the power supply voltage. Switching circuit for driving the DC brushless motor of the compressor and each switching element constituting the switching circuit for the compressor to rotate the DC brushless motor of the compressor at a predetermined rotation speed at a predetermined timing. ON, OFF,
Further, each switching element of the upper and lower arms constituting the blower switching circuit is turned on at a predetermined timing based on the position information obtained by the position detection sensor of the DC motor of the blower.
N, OFF, the ON signal of each switching element of at least one of the upper and lower arms is chopped at a predetermined frequency based on the rotational speed information (target rotational speed), and the ON duty ratio by this chopping is used as the position information. A DC brushless motor for the compressor, and a microcomputer for variably controlling the current speed and the speed information (target speed) obtained by DC brushless motor power supply for blower,
The power supply of the control system of the outdoor unit can be shared, and the microcomputer including the control means has the input / output function necessary for controlling the outdoor unit of the air conditioner, and controls the compressor, the blower, and the outdoor unit. Therefore, it is possible to reduce the power supply circuit of the outdoor unit, and it is possible to control all of the outdoor unit by one microcomputer, which simplifies the power supply circuit and the control circuit of the outdoor unit. , The number of parts can be reduced, the cost of the outdoor unit can be reduced, the outdoor unit can be made more compact, and the rotational speed of the DC brushless motor can be detected to reach the target rotational speed. Since the control is performed in this manner, the rotation speed can be kept constant at the target rotation speed even if the load changes.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an outdoor unit of an air conditioner showing an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram of a blower switching circuit used in the outdoor unit shown in FIG.

FIG. 3 is a time chart illustrating the operation of the DC brushless motor for the blower of the outdoor unit shown in FIG.

FIG. 4 is a flowchart illustrating a method for controlling the air conditioner shown in FIG.

FIG. 5 is a schematic block diagram of an outdoor unit of a conventional air conditioner.

6 is a schematic circuit diagram of a blower switching circuit used in the outdoor unit shown in FIG.

7 is a time chart diagram for explaining the operation of the DC brushless motor of the blower of the outdoor unit shown in FIG.

[Explanation of symbols]

 2 Commercial power supply 6 Position detection sensor (position detection means; Hall element) 12 Voltage control circuit 20 Power supply circuit 20a Rectifier circuit 20b Double voltage circuit 20c Smoothing circuit 21 DC brushless motor (compressor) 22 DC brushless motor (outdoor fan) 23 Compressor Switching Circuit 24 Blower Switching Circuit 25 Position Detection Circuit 26 Comparison Circuit 27 Amplification Circuit 28 Compressor Drive Circuit 29 Upper Arm Drive Circuit 30 Lower Arm Drive Circuit 31 Drive Voltage Control Circuit 32 Microcomputer

Claims (1)

[Claims] 1. At least an indoor unit and an outdoor unit,
In an air conditioner that controls a compressor that constitutes a refrigeration cycle and that controls an outdoor unit blower, a power supply circuit that inputs an input commercial power supply and outputs a predetermined constant DC voltage, and a constant DC voltage by the power supply circuit as a power supply. A DC brushless motor for the blower and a DC brushless motor for the compressor, and a constant DC voltage from the power supply circuit that can be input as a power supply voltage, and a switching circuit for a blower that drives the DC brushless motor for the blower and a DC brushless motor for the compressor. A switching circuit for driving the compressor, a voltage control circuit for stepping down the power supply voltage by the power supply circuit to a general control system power supply voltage of the outdoor unit, and the DC brushless motor of the compressor for rotating at a predetermined rotation speed. Switch for compressor O the switching elements constituting the grayed circuit at a predetermined time
N, OFF, and each switching element of the upper and lower arms constituting the blower switching circuit is turned on and off at a predetermined timing based on the position information by the position detecting means of the DC brushless motor of the blower, and the rotation speed information (target rotation) The ON signal of each switching element of at least one of the upper and lower arms is chopped at a predetermined frequency based on the number), and the ON duty ratio due to the chopping is obtained by the position information. (Target rotation speed) and control means for making it possible to vary the applied voltage of the DC brushless motor of the blower, the DC brushless motor of the compressor and the power supply of the DC brushless motor of the blower, the outdoor unit The control system power source can be shared, and The stage includes a microcomputer for controlling the outdoor unit, and the same microcomputer has an input / output function necessary for controlling the outdoor unit of the air conditioner, and enables control of the compressor, the blower, and the outdoor unit. A method for controlling an air conditioner, which is characterized by the above.