JPH06165568A - Control method for air-conditioner - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] In an air conditioner, the power supply circuit and control circuit are simplified, and a single microcomputer controls the air conditioner and the brushless motor rotation. [Structure] The AC power supply 2 is converted into a DC power supply by the power supply circuit 3, and the DC voltage from the DC power supply is converted into AC by the drive circuit 5 and applied to a plurality of windings of the brushless motor 1, and the rotation of the motor 1 is performed. The child position detection signal is sent to the microcomputer 11
The microcomputer 11 generates a drive signal for turning on the plurality of switch means of the upper and lower arms 5a and 5b of the drive circuit 5 in a predetermined manner so that the motor 1 rotates based on the vertical position detection signal, Of the signals, at least one of the upper and lower arms of the drive circuit 5 for turning on a plurality of switching means of a predetermined arm is chopped at an ON portion of the signal to control the drive circuit 5 so that a plurality of windings of the motor 1 are provided. The DC voltage is converted into an AC voltage, and at the same time, a predetermined chopped AC voltage is applied to control the motor 8 and the outdoor unit.

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 used in an air conditioner having a brushless motor and controlling the rotation of the brushless motor.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, some air conditioners have a three-phase brushless motor 1 in an indoor fan, for example.

In the figure, the air conditioner of this example has a rectifying circuit 3a for obtaining a DC voltage from an input commercial AC power supply 2.
And a power supply circuit 3 including a smoothing capacitor 3b, etc.
And a transformer 4a for converting the DC voltage from the power supply circuit 3 into a variable DC voltage for driving the brushless motor 1,
Transistor 4b, diode 4c and capacitor 4
a switching power supply 4 composed of d and the like, and six transistors connected in a three-phase bridge to convert the variable DC voltage obtained by the switching power supply 4 into an AC voltage and apply it to the three-phase winding of the brushless motor 1. While outputting the rotational speed command of the configured drive circuit 5 and the brushless motor 1, the microcomputer 6 that controls the indoor side of the air conditioner and the transistor 4b are switched, and the rotation from the microcomputer 6 is performed. In order to set the variable DC voltage supplied to the drive circuit 5 to a predetermined voltage based on the number command, a switching signal for setting the ON / OFF ratio of the switching to a predetermined ON / OFF ratio is output, and the brushless motor 1 The position detection signal that is the output of the Hall element 1a that detects the position of the rotor is input and converted into the same position detection signal. The brushless motor 1 Zui
So as to rotate, each of the transistors of the drive circuit 5 is turned on in a predetermined manner to convert the variable DC voltage output from the switching power supply 4 to the three-phase winding of the brushless motor 1 into an alternating current, and apply a drive signal to the alternating current. And a brushless motor control circuit 7 for outputting.

The brushless motor control circuit 7 is composed of a dedicated IC for controlling the brushless motor or the like, and a position detection signal from a hall element 1a which is a position detection sensor provided inside the brushless motor 1 (see FIG. 7). (A)
To (c)), each of the transistors U, V, and V of the drive circuit 5 is rotated so that the brushless motor 1 rotates.
Drive signals U, V, W, for turning on W, X, Y, Z in a predetermined manner
X, Y, Z (shown in FIGS. 7D to 7I) are output. Each of the transistors of the drive circuit 5 is turned on in a predetermined manner by these drive signals, and the variable output DC voltage of the switching power supply 4 is converted into AC voltages U, V, W (shown in FIGS. 7 (k) to (m)). Brushless motor 1 three-phase winding U,
Applied to V and W, the brushless motor 1 rotates.

In the brushless motor control circuit 7, a switching signal (shown in FIG. 7 (j)) for switching the transistor 4b of the switching power supply 4 is output and the microcomputer 6 is also provided.
So that the brushless motor 1 has a predetermined rotation speed based on the rotation speed command of the brushless motor 1 from
The on / off ratio of the switching signal is set to a predetermined on / off ratio. As a result, the output variable DC voltage of the switching power supply 4 is set to a predetermined voltage based on the rotation speed command, so that an AC voltage of a predetermined voltage is applied to the three-phase winding of the brushless motor 1, and the brushless motor is 1
Is controlled to rotate at a predetermined rotation speed.

The microcomputer 6 inputs / outputs to / from various input / output circuits such as indoor temperature detecting means and wind direction plate controlling means necessary for controlling the inside of the air conditioner. Control the inside of the harmony machine.

[0007]

However, in the above air conditioner control method, two control means, that is, the microcomputer 6 and the brushless motor control circuit 7, are necessary for controlling the air conditioner, and the brushless motor is also provided. Since the switching power supply 4 for obtaining the variable DC voltage required to drive the motor 1 is required, the control circuit and the power supply circuit are complicated, the number of parts is large, the cost is increased, and the size is increased. , Which is an obstacle to cost reduction and miniaturization of the air conditioner.

Further, since the ON / OFF ratio of the switching of the transistor 4b of the switching power source 4 is determined by the rotation speed command, even if the load fluctuates and the rotation speed of the brushless motor 1 changes, the switching ON is performed. ,
There was a problem that the off ratio did not change, the actual number of revolutions did not match the value of the number of revolutions command, and the number of revolutions changed with changes in load.

The present invention has been made in view of the above problems, and an object thereof is to simplify a control circuit and a power supply circuit, and to control the air conditioner with a single microcomputer. As a result, the number of parts can be reduced, the cost and size of the air conditioner can be reduced, and the rotation speed of the brushless motor can be kept constant at a predetermined rotation speed even if the load fluctuates. It is to provide a control method of.

[0010]

In order to achieve the above object, the present invention relates to an air conditioner control method having at least a microcomputer for controlling an air conditioner and a brushless motor, and at least a rotor of the brushless motor. Of position detection means for detecting the position of the brushless motor and a plurality of switch means for switching the connection between the plurality of windings of the brushless motor and the positive terminal of the DC power supply And a drive means provided with a lower arm configured by a plurality of switch means for switching the connection between the plurality of windings and the negative terminal of the same DC power supply, and the microcomputer inputs the position detection signal. Based on the same position detection signal, a plurality of switch means forming the upper arm and the lower arm of the drive means are turned on in a predetermined manner. Then, the connection between the positive terminal and the negative terminal of the DC power supply and the plurality of windings of the brushless motor is switched, and the DC voltage from the same DC power supply is converted to AC and applied to the plurality of windings. Turning on a drive signal for generating a drive signal for rotating a motor and for turning on a plurality of switch means constituting at least one of the upper arm and the lower arm of the drive means in the drive signal in a predetermined manner. A portion is a chopping signal having a predetermined on / off ratio for turning on / off the plurality of switch means at a frequency higher than the frequency of the drive signal, and the drive signal using the on portion as a chopping signal and other drive signals From the microcomputer as a drive signal for driving the plurality of switch means of the upper arm and the lower arm of the drive means. The plurality of switch means of the upper arm and the lower arm of the drive means are turned on by the same drive signal in a predetermined manner, and the plurality of switch means of at least one of the upper arm and the lower arm are turned on by the chopping signal when the plurality of switch means are turned on. The switch means is chopped to convert the DC voltage into an AC voltage and at the same time chop, and the chopped AC voltage is applied to the plurality of windings to control the rotation of the brushless motor. Use as a summary.

The microcomputer calculates the rotation speed of the brushless motor based on the position detection signal, and sets a predetermined ON / OFF ratio of the chopping signal so that the calculated rotation speed becomes a predetermined rotation speed. I am trying to change it.

[0012]

With the above structure, the rotation control of the brushless motor and the control of the air conditioner are performed by the one microcomputer. in this case,
The DC voltage from the DC power supply is used as the input power supply voltage of the brushless motor drive means.

In controlling the rotation of the brushless motor,
In the microcomputer, based on a position detection signal from the position detecting means of the brushless motor, a plurality of switch means of the driving means are turned on in a predetermined manner so that the brushless motor rotates, and a plurality of windings of the brushless motor are wound. A drive signal for converting a direct current voltage from a direct current power source into an alternating current and applying the generated drive signal is generated, and a plurality of switch means of at least one of the upper and lower arms constituting the same drive means are turned on in a predetermined manner among the drive signals. The ON portion of the drive signal is a chopping signal for turning on and off the plurality of switch means at a frequency higher than the drive signal when the plurality of switch means is on, and outputs these drive signals from the microcomputer. At this time, the rotation speed of the brushless motor is calculated from the position detection signal, and the on / off ratio of the chopping signal is changed in a predetermined manner so that the calculated rotation speed becomes a predetermined rotation speed.
That is, when the DC voltage is converted to AC and applied to a plurality of windings of the brushless motor, the applied voltage is chopped by the chopping signal so that the applied voltage is varied in a predetermined manner. Is controlled to rotate.

As described above, the variable DC power supply is not required to drive the brushless motor of the air conditioner, and thus the switching power supply is not necessary, and one microcomputer is sufficient as means for controlling the air conditioner. Therefore, the power supply circuit and the control circuit can be simplified and the number of components can be reduced.

Further, since the rotation speed of the brushless motor is controlled so that the rotation speed of the brushless motor is calculated and the rotation speed of the brushless motor becomes a predetermined rotation speed, the rotation speed of the brushless motor is changed to the predetermined rotation speed even if the load changes. It can be constant in number.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the air conditioner of the present invention will be described with reference to FIGS. In the figure, the same parts as those in FIG. 6 and the parts corresponding to the same parts are designated by the same reference numerals, and a duplicate description thereof will be omitted.

In FIG. 1, this air conditioner uses a brushless motor 1 as a motor for driving an indoor blower, and a DC voltage obtained by a power supply circuit 3 for converting a commercial AC power supply 2 into a DC power supply. (For example, 140 V) is converted into an AC voltage by the drive circuit 5 which is a drive means and applied to a plurality of windings of the brushless motor 1. Therefore, a high voltage is used as the brushless motor (for example, three-phase brushless motor; hereinafter referred to as brushless motor) A high voltage type transistor (for example, rated voltage 140V) is used as a plurality of switching means transistors of the drive circuit 5.

The air conditioner also receives a position detection sensor (hall element) 1a inside the brushless motor 1 for detecting the position of the rotor of the brushless motor 1 and an output signal from the hall element 1a. Position detecting circuit configured of a position detecting circuit 10 including a comparing unit and an amplifying unit for outputting a position detecting signal, and an input / output function necessary for indoor control of the air conditioner. To control the rotation of the brushless motor 1 and to control the rotation of the brushless motor 1, a microcomputer 11 that receives a position detection signal from the position detection circuit 10 and outputs a drive signal that controls a plurality of transistors of the drive circuit 5; And a drive circuit 12 for driving a plurality of transistors of the drive circuit 5 by an output drive signal from the microcomputer 11. .

The drive circuit 5 is composed of three transistors U and V which are a plurality of switch means for connecting the positive terminal of the power supply circuit 3 which is a DC power supply and the three-phase winding which is a plurality of windings of the brushless motor 1. , W, the upper arm 5a and the negative terminal of the power supply circuit 3, which is the same DC power supply, and the three transistors X, which are a plurality of switch means for connecting the three-phase windings, which are a plurality of windings of the brushless motor 1. , Y, Z, which is composed of a lower arm 5b, switches the connection between the positive and negative terminals of the power supply circuit 3 which is the same DC power supply and the same three-phase winding to supply the power supply circuit 3 which is the same DC power supply. The DC voltage from is converted into AC voltage and applied to the three-phase winding.

Next, the control method applied to the air conditioner having the above structure will be described with reference to the time chart of FIG. 2. In order to detect the position of the rotor of the brushless motor 1 in the position detecting means. The output signal from the Hall element 1a (shown in FIGS. 2A to 2C) is the position detection circuit 1.
0, the position detecting signal (shown in FIGS. 2D to 2F) is output by the comparing unit and the amplifying unit, and is input to the microcomputer 11.

The microcomputer 11 has a structure in which the respective transistors U of the upper and lower arms 5a and 5b of the drive circuit 5 are arranged so that the brushless motor 1 is rotated based on the same position detection signal inside the microcomputer 11.
V, W, X, Y, Z are turned on in a predetermined manner, and the connection between the positive terminal and the negative terminal of the power supply circuit 3 and the three-phase winding of the brushless motor 1 is switched to the same power supply circuit 3 in the same three-phase winding. Drive signals U, V, W, X, Y, and Z for converting the DC voltage from the AC voltage to the AC voltage and applying the DC voltage are generated, and among the generated drive signals, the upper arm 5a or the lower arm of the drive circuit 5 is generated. At least one arm of the arm 5b, for example, the ON portion of the drive signal for turning on the transistors X, Y, Z of the lower arm 5b at a predetermined frequency is used to turn on the transistors X, Y, Z at a frequency higher than the frequency of the drive signal. Drive signals X, Y, Z (shown in FIGS. 2 (j) to (l)), which are chopping signals having a predetermined on / off ratio for turning on / off, and whose on portions are chopping signals, and other drive signals U. , V, W (Fig. 2 (g) Shown in Itaru (i)) is outputted from the microcomputer 11.

The drive signals U, V, W, X, Y and Z output from the microcomputer 11 are applied to the drive circuit 1.
2 and the drive circuit 12 inputs the upper and lower arms 5a, 5a of the drive circuit 5 according to the input drive signal.
b, each of the transistors U, V, W, X, Y, Z of b is turned on in a predetermined manner, and the transistors X, 5
When Y and Z are turned on, the same transistor is chopped by the chopping signal, so that the DC voltage from the power supply circuit 3 is converted into an AC voltage in the three-phase windings U, V and W of the brushless motor 1. At the same time, the chopped predetermined AC voltages U, V, W (shown in (m) to (o) of FIG. 2) are applied to control the rotation of the brushless motor 1.

The operation of controlling the rotation speed of the brushless motor 1 in the microcomputer 11 will be described in detail with reference to the flow chart of FIG. 3. First, in the microcomputer 11, based on the position detection signal input through the input port. Then, the rotation speed of the brushless motor 1 is calculated (step ST1). This rotation speed is calculated, for example, by inputting three position detection signals (Fig. 2 (d)).
(Shown in (f)) and the time between rising and falling are measured.

Subsequently, the calculated rotation speed is compared with the predetermined rotation speed of the brushless motor 1 (steps ST2 and ST).
4) When the calculated rotation speed is lower than the predetermined rotation speed (step ST2), the ON time of the chopping signal of the ON portion of the drive signal of each transistor of the lower arm 5b forming the drive circuit 5 is increased (OFF time is decreased. The ON / OFF ratio is changed (step ST3), and thereby the voltage applied to the three-phase winding of the brushless motor 1 is increased and the rotation speed of the brushless motor 1 is increased.

On the other hand, when the calculated rotation speed is higher than the predetermined rotation speed (step ST4), the ON time of the chopping signal of the ON portion of the drive signal of each transistor of the lower arm 5b decreases (OFF time increases, ON, OFF). The ratio is varied) (step ST5), whereby the voltage applied to the three-phase winding of the brushless motor 1 is lowered, and the rotation speed of the brushless motor 1 is lowered.

By repeating the steps ST1 to ST5, the rotation speed of the brushless motor 1 is variably controlled to approach a predetermined rotation speed, and the brushless motor 1 is rotationally controlled at a predetermined rotation speed.

In the above embodiment, the hall element of the position detecting sensor 1a and the comparing means and amplifying means of the position detecting circuit 10 are used as the position detecting means of the brushless motor 1, but the comparing means and amplifying means are used. Means may be provided inside the microcomputer 11, the Hall element may serve as position detecting means, and the output signal of the Hall element may serve as a position detecting signal. Further, the Hall element and the comparing means and amplifying means may be provided inside. It is also possible to use the Hall ICs that it has as position detecting means and use the output of this Hall IC as the position detection signal. Further, the stator winding of the brushless motor 1 may be shared as a position detecting sensor, and the terminal voltage of this stator winding may be input to the position detecting circuit by the integrating means and the comparing means to obtain the position detecting signal. In this case, the position detecting means is the stator winding and the position detecting circuit. Further, the integrating means and the comparing means may be provided inside the microcomputer 11, the stator winding may serve as the position detecting means, and the terminal voltage may serve as the position detecting signal. In addition, brushless motor 1
Any means for detecting the position of the rotor and outputting a position detection signal may be used.

In the above embodiment, the brushless motor 1 has been described as a motor for driving the indoor blower, but the present invention is not limited to this, and it drives a motor or a compressor for driving the outdoor blower. A motor may be used, and any other motor used in an air conditioner may be used. Further, regarding the microcomputer 11 as well,
The control of the indoor side is not limited to the one described in the above embodiment, but may be the control of the outdoor side or the control of the indoor side and the outdoor side, as long as it controls the air conditioner. .

By the way, as shown in FIG. 4, the microcomputer 11 has an air conditioner control means 1 having an input / output function and the like necessary for controlling the air conditioner.
1a and brushless motor control means 11b for generating a drive signal to be output to control the rotation of the brushless motor 1 used in the air conditioner.

The brushless motor control means 11b is
Drive signal generating means 11c for generating a drive signal for turning on a plurality of transistors of the upper and lower arms 5a and 5b of the drive circuit 5 in a predetermined manner so that the brushless motor 1 rotates based on the position detection signal of the brushless motor 1; A chopping signal generating means 11d for generating a chopping signal having a predetermined ON / OFF ratio at a frequency higher than the frequency of the drive signal generated by the drive signal generating means 11c, and for generating ON / OFF timing by the timer means.
The generated drive signal and the generated chopping signal are input, and the drive circuit 5 among the input drive signals is input.
At least one of the upper and lower arms 5a and 5b, for example, a chopping means 11e for chopping the ON portion of the drive signal for turning on the transistor of the lower arm 5b in a predetermined manner by the chopping signal. The chopping signal generation means 11d is the comparison means 1
1f, memories 11g and 11h, and timer counter 11
i.

This example will be described with reference to the time chart of FIG. 5. The brushless motor control means 1 is described above.
1b is a brushless motor 1 shown in FIGS.
Is input to the drive signal generation means 11c, and the drive signal generation means 11c causes the transistors U, V, V of the drive circuit 5 to rotate the brushless motor 1 based on the input position detection signal. The drive signals U, shown in FIGS. 3D to 3I, which turn on W, X, Y, and Z in a predetermined manner.
V, W, X, Y, Z are generated. On the other hand, the chopping signal generating means 11d generates a chopping signal shown in FIG. 9 (j) having a predetermined ON / OFF ratio at a frequency higher than the frequency of the generated drive signal.

When the chopping signal is generated,
The periods Tf of the chopping signal are stored in the memories 11g and 11h.
The predetermined on-time Ton of the chopping signal is set, the timer counter 11i is reset and started, and the output chopping signal is set to the H level (ON). Next, the comparison means 11f compares the count value of the timer counter 11i with the predetermined on-time Ton of the chopping signal of the memory 11h,
When they match, the output chopping signal is set to the L level (off). Then, when the count value of the timer counter 11i and the cycle Tf of the chopping signal of the memory 11g match, the timer counter 11i is reset and started again. The output chopping signal is set to the H level (ON) again.

Since the same processing as described above is repeated thereafter, the chopping signal is generated by the chopping signal generating means. The generated chopping signal and the generated drive signals U, V, W, X, Y and Z are input to the chopping means 11e, and the drive circuit 5 of the drive signals input by the chopping means 11e is input. The on portions of the drive signals X, Y, Z for turning on the transistors X, Y, Z of the lower arm 5b in a predetermined manner are chopped by the chopping signal. This is because the drive signals X, Y, Z (shown in FIGS. 9 (g) to 9 (i)) for turning on the transistors X, Y, Z of the lower arm 5b and the chopping signal (j) in FIG. Drive signal X, Y, Z obtained by performing a logical product with a chopping signal in the chopping means 11e. As shown in FIG. 4B, the ON amount is used as the chopping signal shown in FIG. 7J and is output from the chopping means 11e. Incidentally, the generation drive signals U, V, shown in (d) to (f) of FIG.
W is as it is from the chopping means 11e in the same figure (k).
To (m), the transistor U of the upper arm 5a,
It is output as a drive signal for turning on V and W in a predetermined manner. The microcomputer 11 obtains the drive signals U, V, W, X, Y, shown in (k) to (p) of FIG.
Z is output and, as shown in the flow chart of FIG. 3, the memory 1 of the chopping signal generating means 11d.
On time Ton of chopping signal set to 1h
By changing the ON / OFF ratio of the generated chopping signal according to the calculated rotation speed of the brushless motor 1 and the predetermined rotation speed, and outputting the chopping signal of the ON portion of the drive signals X, Y, Z to be output. Rotation speed control is performed by changing the on / off ratio. Further, the cycle Tf of the chopping signal may be changed as necessary.

As described above, as a means for controlling the air conditioner and a means for controlling the rotation of the brushless motor 1 used in the air conditioner, instead of the brushless motor control circuit 7 and the microcomputer 6 of the conventional example, one is used. It can be done with the microcomputer 11, and since a switching power supply is not required as a power supply circuit,
The control circuit and the power supply circuit can be simplified, the number of parts can be reduced, and the cost and size of the air conditioner can be reduced. Further, since the rotation speed of the brushless motor 1 is calculated and the rotation control is performed so as to reach the predetermined rotation speed, even if the load changes, the rotation speed of the brushless motor 1 does not change, It is made constant at a predetermined rotation speed.

[0035]

As described above, according to the air conditioner control method of the present invention, the rotation of the brushless motor used in the air conditioner can be controlled by one microcomputer controlling the air conditioner. Since a DC power supply for driving the brushless motor is not required, the control circuit and power supply circuit can be simplified, the number of parts can be reduced, and the cost and size of the air conditioner can be reduced. In addition, the rotation speed of the brushless motor is calculated, and the control is performed so that the rotation speed becomes a predetermined rotation speed. Therefore, even if the load changes, the rotation speed can be kept constant at the predetermined rotation speed. It has a useful effect that

[Brief description of drawings]

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

FIG. 2 is a time chart diagram illustrating a method of controlling a brushless motor used in the air conditioner shown in FIG.

FIG. 3 is a flowchart illustrating a method of controlling a brushless motor used in the air conditioner shown in FIG.

FIG. 4 is a schematic block diagram of a microcomputer that controls the air conditioner shown in FIG. 1.

5 is a time chart diagram for explaining the operation of the microcomputer shown in FIG.

FIG. 6 is a schematic block diagram of a control circuit of a conventional air conditioner.

7 is a time chart diagram illustrating a method of controlling a brushless motor used in the air conditioner shown in FIG.

[Explanation of symbols]

 1 Brushless Motor 1a Position Detection Sensor (Hall Element) 2 AC Power Supply 3 Power Supply Circuit 5 Drive Circuit 5a Upper Arm (Drive Circuit) 5b Lower Arm (Drive Circuit) 10 Position Detection Circuit 11 Microcomputer 11a Air Conditioner Control Means 11b Brushless Motor control means 11c Drive signal generation means 11d Chopping signal generation means 11e Chopping means 11f Comparison means 11g, 11h Memory 11i Timer counter 12 Drive circuit

Claims (4)

[Claims] 1. A method of controlling an air conditioner having a microcomputer for controlling at least an air conditioner and a brushless motor, comprising: position detecting means for detecting a position of at least a rotor of the brushless motor and outputting a position detection signal. And an upper arm constituted by a plurality of switch means for switching the connection between the plurality of windings of the brushless motor and the positive terminal of the DC power supply, and the connection between the plurality of windings of the brushless motor and the negative terminal of the DC power supply. And a driving means having a lower arm configured by a plurality of switching means for switching, wherein the microcomputer inputs the position detection signal and based on the position detection signal, the upper arm and the lower arm of the driving means. A plurality of switch means forming the arm are turned on in a predetermined manner, and the positive terminal and the negative terminal of the DC power source and the bra The connection of the windingless motor to the plurality of windings is switched, and the DC voltage from the same DC power source is converted to AC and applied to the plurality of windings to generate a drive signal for rotating the same brushless motor. Of the drive signals, a plurality of ON portions of the drive signal for turning ON a plurality of switch means constituting at least one of the upper arm and the lower arm of the drive means at a frequency higher than the frequency of the drive signal. Is used as a chopping signal having a predetermined on / off ratio for turning the switch means on and off in a predetermined manner, and a drive signal using the on portion as a chopping signal and other drive signals are output to a plurality of upper and lower arms of the drive means. The signal is output from the microcomputer as a drive signal for driving the switch means, and the upper and lower arms of the drive means are output by the drive signal. The plurality of switch means of the arm is turned on in a predetermined manner, and when the plurality of switch means of at least one of the upper arm and the lower arm is turned on, the plurality of switch means are chopping-driven by the chopping signal, and the DC voltage is changed. A method of controlling an air conditioner, comprising: converting to an AC voltage, chopping the same, and applying the chopped AC voltage of a predetermined voltage to the plurality of windings to control the rotation of the brushless motor. 2. The microcomputer calculates the number of rotations of the brushless motor based on the position detection signal, and the chopping signal is turned on and off in a predetermined manner so that the calculated number of rotations becomes a predetermined number of rotations. The method for controlling an air conditioner according to claim 1, wherein the ratio is made variable. 3. The microcomputer has at least brushless motor control means for generating the output drive signal for controlling the rotation of the brushless motor, and the brushless motor control means receives the position detection signal of the brushless motor. Drive signal generating means for generating a drive signal for turning on a plurality of switch means of the upper arm and the lower arm of the drive means in a predetermined manner so that the brushless motor rotates based on the same; and a frequency higher than the frequency of the generated drive signal. , A chopping signal generating means for generating a chopping signal having a predetermined on / off ratio, and a timer means for generating on / off timing of the chopping signal; and among the generated drive signals, the upper arm of the driving means. Or multiple switches on at least one of the lower arms 3. An air conditioner control method according to claim 1, further comprising chopping means for chopping the ON portion of the drive signal for turning on the means in a predetermined manner by the generated chopping signal. 4. The air conditioner according to claim 3, wherein the chopping means calculates a logical product or a logical sum of a drive signal for chopping the on portion and the generated chopping signal, and chops the on portion of the drive signal. Control method.