JP2002218789A - Controller of dc brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of, when a DC brushless motor with a large load fluctuation is controlled by the conventional control method, that a current phase is to be constant during one turn, as the current and revolution of the motor are changed during one turn, the current phase is not always properly controlled in one turn and hence the optimum phase control for the efficiency improvement, noise suppression, and vibration suppression of the motor cannot be realized. SOLUTION: This controller of a DC brushless motor, which controls load with large fluctuations during one turn, detects a load fluctuation during one turn and controls the current phase of the motor during one turn, so as to make the current phase of the motor most suitable for the load fluctuations of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a DC brushless motor for driving a load having a large fluctuation during one rotation, for example, a compressor of an air conditioner.

[0002]

2. Description of the Related Art A means for controlling a current phase of a motor with respect to a back electromotive voltage of a rotor, which has been used in a control device of a DC brushless motor, will be described with reference to FIGS.

FIG. 11 shows a DC brushless motor of 120 motors.
Is a voltage / current waveform when controlled by a rectangular wave, where 1 is the back electromotive voltage of the rotor appearing in one phase of the stator winding, and 2 is 1
And the motor current in phase. 3 is the back electromotive voltage of the rotor 1
And the motor current 2 (current phase).

[0004] The magnitude of the current phase 3 of the motor has a great effect on motor efficiency, noise and vibration. For example, when controlling the motor for the purpose of maximum efficiency, it is necessary to control the magnetic flux of the rotor to be always orthogonal to the current phase 3. FIG.
2 shows an example of the current waveform 2 when the current phase 3 of the motor is changed. As shown in FIG.
Is changed, the current waveform 2 also changes. in this way,
Changes in motor efficiency, noise, and vibration depending on the current phase 3 also appear in the motor current waveform 2.

Since the optimum value of the current phase 3 varies depending on the rotation speed and the load, the current phase 3 is controlled according to the conditions. 13 and 14 show examples of controlling the current phase 3 of the motor. FIG. 13 is a control example of the current phase 3 for the rotation speed, and FIG. 14 is a control example of the current phase 3 for the load.

As described above, conventionally, optimal control of motor efficiency, noise, and vibration has been performed by controlling the magnitude of the current phase 3 of the motor.

[0007]

However, in a control device of a brushless motor for controlling a load having a large fluctuation during one rotation using the conventional control method as described above,
There has been a problem that the current phase of the motor cannot always be optimally controlled.

FIG. 15 shows an example of a current waveform when a load having a large fluctuation during one rotation is controlled by using a control method in which the applied voltage and the current phase during one rotation are constant. In the example of FIG. 15, when the load is large during one rotation, the current is large and the rotation speed is low. When the load is small, the current is small and the rotation speed is high. As described above, if the motor current or the rotation speed changes during one rotation, the noise or vibration increases, and the armature reaction also changes under the condition where the current phase is fixed. ,
Vibration cannot be controlled to the optimal current phase.

FIG. 16 shows an example of a current waveform in the case where a conventional load control method in which the current phase during one rotation is constant is used to control a load having a large fluctuation during one rotation. When the load fluctuation is large, torque control is generally used to keep the rotation speed of the motor constant as shown in FIG. As shown in FIG. 16, when the torque control is performed, the speed fluctuation during one rotation can be suppressed, but the current fluctuation is large, and the current phase deviates from the optimum phase (the current waveform is shown in FIG.
(Corresponding to (3)). Thus, when the conventional method is used, it can be seen that the efficiency, noise, and vibration conditions are not at the optimum current phase at all points during one rotation. This is because the influence such as the armature reaction changes with the change of the motor current.

As described above, in a DC brushless motor control device that controls a load having large fluctuations during one rotation, the motor current and the rotation speed change during one rotation due to the load fluctuation, and the armature reaction changes. It is necessary to change the current phase. However, in the conventional control method as described above, the current phase is set to a fixed value according to the average rotation speed or the average load as shown in FIGS. There was a problem that phase control was impossible.

The present invention is to solve such a conventional problem, and to control a load having a large fluctuation during one rotation.
An object of the present invention is to provide a control device for a C brushless motor that can always control a current phase to an optimum value.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for controlling a load having a large fluctuation during one rotation.
The control device of the C brushless motor detects a load change and controls the current phase of the motor during one rotation so that the current phase of the motor always becomes optimal with respect to the load change.

By controlling the current phase of the motor during one rotation, it is possible to optimize the phase control in order to always increase the efficiency of the motor, or reduce noise and vibration.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a DC brushless motor control device for controlling a load having a large fluctuation during one rotation, the invention according to the first aspect detects a load fluctuation during one rotation and changes the current phase of the motor. To be optimal for load fluctuations,
This is to change the current phase of the motor during one rotation. By performing such control, it is possible to always perform optimal phase control for improving the efficiency of the motor, or reducing noise and vibration.

According to a second aspect of the present invention, there is provided a DC brushless motor control device for controlling a load having a large fluctuation during one rotation, which suppresses a speed fluctuation by using a torque control. The current phase of the motor during one rotation is changed so that the phase becomes optimal with respect to load fluctuation. By controlling in this manner, it is possible to always carry out optimal phase control for increasing the efficiency of the motor, or reducing the noise and vibration, as in the first aspect of the invention.

According to a third aspect of the present invention, in the control device for a DC brushless motor according to the first aspect, for controlling the phase of the motor current, one rotation is divided into a plurality of rotations to detect the rotation speed of the motor. And a device for storing a current phase corresponding to the detected rotation speed of the motor. By performing such control, the invention described in claim 1 can be realized by a simple control method.

According to a fourth aspect of the present invention, in the control apparatus for a DC brushless motor according to the first or second aspect, for controlling the phase of the motor current, one rotation is divided into a plurality of rotations to divide the motor current. A device that detects and stores a current phase corresponding to the detected motor current is used.
By performing such control, the invention described in claims 1 and 2 can be realized by a simple control method.

According to a fifth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, for controlling the phase of the motor current, one rotation is divided into a plurality of rotations to rotate the motor. The apparatus uses a device that detects a speed and a current and stores a current phase corresponding to the detected rotation speed and the current of the motor. By controlling in this way, the invention described in claim 1 or 2 can be realized by a simple control method, similarly to the third and fourth aspects.

According to a sixth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, the current phase of the motor during one rotation is controlled.
It uses a device that stores a change pattern of the current phase corresponding to the average rotation speed of the motor. By performing such control, the invention described in claims 1 and 2 can be realized by a simple control method.

According to a seventh aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, the current phase of the motor during one rotation is controlled.
It uses a device that stores a change pattern of the current phase corresponding to the average current (load) of the motor. By controlling in this way, the invention described in claim 1 or 2 can be realized by a simple control method as in claim 3.

According to an eighth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, the current phase of the motor during one rotation is controlled.
It uses a device that stores a change pattern of the current phase corresponding to the average rotation speed of the motor and the current (load). By controlling in this way, the invention described in claim 1 or 2 can be realized by a simple control method, similarly to the sixth and seventh aspects.

According to a ninth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, the current phase of the motor during one rotation is controlled.
A current phase pattern storage device according to any one of claims 3 to 8 is used in combination. By performing such control, the invention described in claims 1 and 2 can be realized by a relatively simple control method.

According to a tenth aspect of the present invention, in the control device for a DC brushless motor according to any one of the first to ninth aspects, the number of phase changes in the phase control of the motor current during one rotation is determined. Assuming that the number of times of switching the motor phase current is n, the number of times is two or more and n or less. The greater the number of times, the more the invention according to claim 1 or 2 can be realized with better responsiveness of current phase control to load fluctuation. Further, the smaller the number of times, the more the claim 1
In implementing the invention described in (1) or (2), the processing load on the control device can be reduced.

According to an eleventh aspect of the present invention, the number of phase changes in the phase control of the motor current during one rotation according to the tenth aspect is changed according to the rotation speed of the motor. By performing such control, the number of phase changes during one rotation can be optimally controlled according to the margin of the processing speed.

According to a twelfth aspect of the present invention, the number of phase changes in the phase control of the motor current during one rotation according to the tenth aspect is optimally changed according to the magnitude of a load change. By controlling in this way, the number of phase changes during one rotation can be optimally controlled as needed according to the magnitude of the load fluctuation.

According to a thirteenth aspect of the present invention, the number of phase changes in the phase control of the motor current during one rotation according to the tenth aspect is changed according to the rotation speed and the current of the motor. By performing such control, the number of phase changes during one rotation can be optimally controlled according to the processing speed and the magnitude of load fluctuation.

According to a fourteenth aspect, any one of the first to thirteenth aspects is applied to a DC brushless motor having a compressor as a load. By performing such control, it is possible to optimally control a phase change during one rotation of the DC brushless motor for a compressor having a large load variation during one rotation.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a current waveform of the embodiment 1. In a DC brushless motor control device for controlling a load having a large fluctuation during one rotation, a current phase during one rotation is optimized. FIG. 7 is a current waveform diagram when the control is performed in the following manner.

When the current phase during one rotation is changed as shown in FIG. 1, the current waveform is apparent as compared with the conventional example in which the current phase during one rotation is constant as shown in FIG. Different, different in efficiency, noise and vibration.

When the motor current changes during one rotation due to a load change, the effect of the armature reaction of the current on the magnetic field of the motor increases as the current increases. Therefore, when the load fluctuation is large, the magnetic flux density of the motor stator fluctuates greatly during one rotation of the motor.

For example, when controlling a motor for the purpose of improving efficiency, it is necessary to control the current so that it is always orthogonal.
However, as shown in FIG. 15, when the phase of the current does not change in one rotation, it is impossible to always control the fluctuating magnetic field with the maximum efficiency. Control. On the other hand, in the first embodiment, the current phase is changed during one rotation as shown in FIG.

Therefore, by controlling the current phase during one rotation as in the first embodiment, it becomes possible to control the brushless motor under the optimum conditions of efficiency, noise and vibration.

(Embodiment 2) FIG. 2 shows a current waveform of Embodiment 2 in which a torque control is performed in a DC brushless motor control device for controlling a load having a large fluctuation during one rotation. It is a current waveform controlled so that a current phase becomes optimal.

As is clear from the comparison between the current waveform in FIG. 2 and the current waveform in the conventional example in FIG. 16, it is common that the peak value of the current fluctuates according to the load, but the current phase is different, and the efficiency and noise , The vibrations are also different.

Similarly to the first embodiment, when the motor is controlled for the purpose of improving the efficiency, for example, if the current phase does not change during one rotation as shown in FIG. It is impossible, and a fixed and efficient phase is selected and controlled. On the other hand, in the second embodiment, since the current phase is changed during one rotation as shown in FIG. 2, the control can always be performed with the maximum efficiency.

Therefore, as shown in the second embodiment, even in the case of performing torque control, by controlling the current phase during the above-mentioned one rotation, the efficiency, noise, and vibration of the DC brushless motor can be improved under optimum conditions. Can be controlled.

(Embodiment 3) FIG. 3 is a diagram showing a control method according to Embodiment 3, and is a diagram showing the relationship between the rotation speed of the motor and the current phase when the phase is controlled according to the load fluctuation during one rotation. It is. When the load fluctuates greatly, the rotation speed changes every moment during one rotation as shown in FIG. In the third embodiment, the current phase during one rotation is controlled based on FIG. 3 according to the rotation speed that changes during one rotation.

By controlling the current phase based on the above method, the current phase control during one rotation can be realized by a simple method.

(Embodiment 4) FIG. 4 is a diagram showing a control method according to Embodiment 4, and is a diagram showing the relationship between the motor current and the current phase when the current phase is controlled according to the load fluctuation during one rotation. is there. When the load fluctuates greatly, the motor current changes every moment during one rotation as described above. In the fourth embodiment, the current phase is controlled based on FIG. 4 according to the motor current that changes during one rotation.

By controlling the current phase based on the above method, the current phase control during one rotation can be realized by a simple method.

(Embodiment 5) FIG. 5 is a diagram showing a control method according to Embodiment 5, in which the average rotation speed of the motor and the rotation speed during one rotation are controlled when the phase is controlled according to the load fluctuation during one rotation. It is a relation diagram of a current phase change. In this embodiment, the current phase change during one rotation when the motor is rotating at a certain speed as shown in FIG. 5 is set, and the current phase is controlled based on FIG. 5 according to the rotation speed of the motor. I do.

By controlling the current phase based on the above method, the current phase control during one rotation can be realized by a simple method.

(Embodiment 6) FIG. 6 is a diagram showing a control method according to Embodiment 6, in which the average current value and the current phase change of the motor when the current phase is controlled according to the load fluctuation during one rotation. It is a relation diagram of a value. In this embodiment, a current phase that changes during one rotation when the motor rotates at a certain speed as shown in FIG. 6 is determined, and the current phase is controlled based on FIG. 6 according to the motor current.

By controlling the current phase based on the above method, the current phase control during one rotation can be realized by a simple method.

(Embodiment 7) FIG. 7 is a diagram showing a control method of Embodiment 7. In the seventh embodiment, the three-phase four-pole motor is controlled using the 120 ° conduction method, and the current phase is changed twice during one rotation as shown in FIG.

When the current phase changes twice during one rotation as in this embodiment, the current phase control can be realized by a simple calculation.

(Eighth Embodiment) FIG. 8 is a diagram showing a control method of an eighth embodiment. In the eighth embodiment, a three-phase four-pole motor is controlled by using the 120 ° conduction method. As shown in the figure, the phase is changed 12 times (the number of times of switching of the current direction in the motor) during one rotation. ing.

If the load fluctuation during one rotation is extremely large, it is necessary to increase the current phase change. Therefore, by switching the current phase finely as in the present embodiment, it is possible to realize the optimal current phase control for high efficiency, low noise and low vibration.

(Embodiment 9) FIG. 9 is a diagram showing a control method of Embodiment 9, in which the number of times of switching the current phase during one rotation is changed according to the rotation speed of the motor.

As in this embodiment, when the number of phase switching is changed according to the rotation speed of the motor, the phase change during one rotation can be optimally controlled according to the margin of the processing speed.

(Embodiment 10) FIG. 10 is a diagram showing a control method according to Embodiment 10. In Embodiment 10, the number of switching of the current phase during one rotation is changed according to the magnitude of the motor current. .

When the number of times of switching the current phase is changed according to the motor current as in this embodiment, the phase change during one rotation can be optimally controlled according to the necessity depending on the magnitude of the load fluctuation. .

The present invention is not limited to the above-described embodiment. For example, the following case is also possible.

That is, first, each of the optimal current phase control methods described in the third to sixth embodiments of the present invention may be combined. Second, optimal current phase control may be performed by setting the number of times of switching of the current phase during one rotation to an arbitrary number of times from 2 to n (number of times of switching in the current direction). Thirdly, the control methods of the number of switching of the current phase described in the ninth and tenth embodiments of the present invention may be combined. Fourthly, phase control in which the relationship between the current phase and the rotation speed or current control of the motor described in the embodiment of the present invention is linear, stepped, or curved may be performed. Fifth, the phase control of the present invention may be performed even when the fundamental wave of the voltage applied to the motor is a sine wave or a waveform having a conduction width other than 120 °.

[0056]

As is apparent from the above embodiment, the invention according to claim 1 detects a load change during one rotation in a DC brushless motor control device for controlling a load having a large change during one rotation. The current phase of the motor during one revolution is changed so that the current phase of the motor is optimized with respect to load fluctuations. By controlling in this manner, the efficiency of the motor is constantly improved or the noise is reduced. This has the effect of reducing vibration.

According to a second aspect of the present invention, there is provided a DC brushless motor control device for performing torque control, wherein a load fluctuation is detected, and the motor is rotated during one rotation so that the current phase of the motor is optimized with respect to the load fluctuation. The phase of the current is changed, and by controlling as described above,
As in the invention described in (1), there is an effect that the efficiency of the motor can be always improved, or noise and vibration can be reduced.

According to a third aspect of the present invention, in the control device for a DC brushless motor according to the first aspect, a current phase corresponding to a rotation speed of the motor that changes during one rotation is used for controlling a phase of the motor current. Since the storage device is used, the invention described in claim 1 can be easily realized.

According to a fourth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, a current corresponding to the motor current that changes during one rotation is used for phase control of the motor current. Since a device for storing a phase is used, the invention described in claim 1 or 2 can be easily realized.

According to a fifth aspect of the present invention, in the control device for a DC brushless motor according to the first aspect, for controlling the phase of the motor current, the DC brushless motor corresponds to the motor speed and motor current that change during one rotation. Since a device for storing a current phase is used, an effect that the invention described in claim 1 or 2 can be easily realized, similarly to the third and fourth aspects.

According to a sixth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, since the current phase of the motor during one rotation is controlled, it corresponds to the average rotation speed of the motor. The present invention uses a device for storing the current phase change pattern, and has an effect that the invention according to claim 1 or 2 can be easily realized.

According to a seventh aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, the average current (load) of the motor is controlled to control the current phase of the motor during one rotation. 2. An apparatus for storing a change pattern of a current phase corresponding to the above-mentioned method.
Or 2 can be easily realized.

According to an eighth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, since the current phase of the motor during one rotation is controlled, the average rotation speed of the motor and the motor are controlled. A device for storing a change pattern of a current phase corresponding to the average current (load) of the present invention is used.
Or 2 can be easily realized.

According to a ninth aspect of the present invention, in the control device for a DC brushless motor according to the first or second aspect, the current phase of the motor during one rotation is controlled. The present invention has an effect that the invention according to claim 1 or 2 can be easily realized.

According to a tenth aspect of the present invention, in the control device for a DC brushless motor according to any one of the first to ninth aspects, the number of phase changes in performing the phase control of the motor current during one rotation is one. Assuming that the number of times of switching of the motor phase current during rotation is n, the number is changed from 2 times to n times. The greater the number of times, the better the responsiveness of the current phase control with respect to the load fluctuation is to improve the effect of the invention of claim 1 or 2, and the less the number of times, the greater the effect of the invention of claim 1 or 2. In the implementation, there is an effect that the processing time of the CPU used in the control device can be reduced.

According to an eleventh aspect of the present invention, the number of phase phase changes of the motor current during one rotation according to the tenth aspect is changed in accordance with the average rotation speed of the motor. (1) The number of phase changes during one rotation can be optimally controlled according to the margin of the processing speed of the CPU used in the control device.

According to a twelfth aspect of the present invention, the number of phase changes of the motor current during one rotation according to the tenth aspect is optimally changed according to the magnitude of the load fluctuation. As a result, the number of phase changes during one rotation can be optimally controlled according to the necessity due to load fluctuation.

According to a thirteenth aspect of the present invention, the number of phase changes of the motor current during one rotation according to the tenth aspect is changed according to the average rotation speed and the current of the motor. As a result, the number of phase changes during one rotation can be optimally controlled with respect to the processing speed of the CPU used in the control device and the magnitude of load fluctuation.

According to a fourteenth aspect of the present invention, any one of the first to thirteenth aspects is applied to a DC brushless motor having a compressor as a load. This has the effect that the phase change during one rotation of the DC brushless motor for a compressor having a large load fluctuation during rotation can be optimally controlled.

[Brief description of the drawings]

FIG. 1 is a diagram showing a current waveform according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a current waveform according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a control method according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a control method according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a control method according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a control method according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing a control method according to a seventh embodiment of the present invention.

FIG. 8 is a diagram showing a control method according to an eighth embodiment of the present invention.

FIG. 9 is a diagram showing a control method according to a ninth embodiment of the present invention.

FIG. 10 is a diagram showing a control method according to a tenth embodiment of the present invention.

FIG. 11 is a diagram showing a 120-degree conduction control waveform showing a conventional example.

12A is a diagram showing characteristics in the case of a current phase advanced from FIG. 12B under a constant load in the conventional example, and FIG. 12B is a diagram showing characteristics in the case of an optimal current phase under a constant load in the conventional example. FIG. 4C is a diagram showing characteristics of a conventional example at a constant load and a current phase delayed from that of FIG.

FIG. 13 is a diagram showing a phase rotation speed control method of a conventional example.

FIG. 14 is a diagram showing a conventional phase load control method.

FIG. 15 is a diagram showing a current waveform (constant voltage control) of a conventional example.

FIG. 16 is a diagram showing a current waveform (torque control) of a conventional example.

[Explanation of symbols]

 1 Back electromotive voltage of rotor 2 Motor current 3 Current phase

Claims (14)

[Claims] 1. A control device for a DC brushless motor for controlling a load having a large fluctuation during one rotation, wherein the control device includes a phase difference between a back electromotive voltage generated by rotation of the motor and a motor current (hereinafter, referred to as a motor current). Means for controlling current phase), means for detecting load fluctuation during one rotation, and changing the current phase of the motor during one rotation so that the current phase of the motor is always optimal with respect to the load fluctuation. A control device for a DC brushless motor, characterized by comprising means. 2. A control device for a DC brushless motor which controls a load having a large fluctuation during one rotation, controls a voltage applied to the motor in order to suppress a rotation speed fluctuation during one rotation (hereinafter referred to as torque control). A control unit for controlling a current phase of the motor, a unit for detecting a load change during one rotation, and a control unit for making the current phase of the motor always optimal for the load change. Means for changing the current phase of the motor during one rotation of the motor. 3. The control device according to claim 1, wherein, as means for determining a current phase of the motor that changes during one rotation, one rotation is divided into a plurality of parts and a rotation speed of the motor is detected. 2. The DC brushless motor control device according to claim 1, wherein a device that stores a set value of a current phase is used. 4. The control device according to claim 1, wherein one of the rotations is divided into a plurality of parts, a motor current is detected, and a current phase corresponding to the value of the motor current is determined. 3. The control device for a DC brushless motor according to claim 1, wherein a device for storing the set value of the DC brushless motor is used. 5. The controller according to claim 1, wherein one rotation is divided into a plurality of parts, and the rotation speed and the motor current of the motor are detected. 2. The DC brushless motor control device according to claim 1, wherein a device for storing a set value of a current phase corresponding to the motor current is used. 6. The control device according to claim 1, wherein a means for storing a set value of a current phase corresponding to an average rotation speed of the motor is used as means for determining a current phase of the motor that changes during one rotation. D according to claim 1 or 2
Control device for C brushless motor. 7. The control device according to claim 1, wherein a device that stores a set value of a current phase corresponding to an average current of the motor is used as means for determining a current phase of the motor that changes during one rotation. Item 3. A control device for a DC brushless motor according to item 1 or 2. 8. The control device according to claim 1, wherein a means for storing a set value of a current phase corresponding to an average rotation speed and an average current of the motor is used as means for determining a current phase of the motor that changes during one rotation. The control device for a DC brushless motor according to claim 1 or 2, wherein: 9. The controller according to claim 3, wherein the controller determines a current phase of the motor that changes during one rotation.
A control device for a DC brushless motor according to claim 1 or 2, wherein the phase storage device according to any one of (1) to (8) is used in combination. 10. The controller according to claim 1, wherein the number of times of changing the current phase of the motor during one rotation is n times, where n is the number of switching of each phase current of the motor during one rotation. The control device for a DC brushless motor according to any one of claims 1 to 9, wherein: 11. The control device according to claim 1, wherein the number of times of changing the current phase of the motor during one rotation is determined in accordance with the average rotation speed of the motor.
A control device for the DC brushless motor according to the above. 12. The DC according to claim 1, wherein the control device determines the number of times of changing the current phase of the motor during one rotation in accordance with the motor current.
Control device for brushless motor. 13. The DC brushless motor according to claim 1, wherein the control device determines the number of times of changing the current phase of the motor during one rotation according to the average rotation speed and the current of the motor. Control device. 14. The DC brushless motor control device according to claim 1, wherein the motor is a compressor motor.