JPH08191587A - Method and equipment for controlling brushless motor - Google Patents

Abstract

PURPOSE: To make the rotation of a brushless motor smooth and to suppress the generation of vibration or noise by making the impression voltage of each armature winding variable in conformity with the fluctuation pattern of a load torque for each of a plurality of sections obtained by dividing one period of a rotor of the brushless motor, on the occasion of controlling the rotation of the rotor. CONSTITUTION: One period (one revolution) of the rotor 1a of a brushless motor is divided into a plurality of sections on the basis of detection signals Ub, Vb and Wb of positions of the rotor 1a outputted by a position detecting part 3, and the PWM ON time of a control signal for driving an inverter part 2 is corrected in conformity with a load torque for each section. In other words, the impression voltage of the armature winding of the brushless motor 1 is made large for the section wherein the load torque is large, while the impression voltage of the armature winding of the brushless motor 1 is made small for the section wherein the load torque is small. Thereby the rotation of the brushless motor 1 can be made smooth and the generation of vibration or noise can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control technology of a commutatorless motor (hereinafter referred to as a brushless motor) used in a compressor of an air conditioner, and more specifically, it relates to a load torque during one rotation. TECHNICAL FIELD The present invention relates to a brushless motor control method and apparatus for smooth rotation regardless of fluctuations.

[0002]

2. Description of the Related Art When a brushless motor is used as a motor of a compressor or the like, for example, a control device shown in FIG. 4 is required. In the figure, this control device includes an inverter unit 2 that switches a DC power supply and applies it to a brushless motor 1, and when the brushless motor 1 is sensorless, terminal voltages U and V of the armature winding of the brushless motor 1. , W, and a position detector 3 for detecting the position of the rotor 1a and outputting position detection signals Ub, Vb, Wb,
A control unit 4 which outputs a control signal for controlling the rotation of the brushless motor 1 based on the position detection signals Ub, Vb, Wb, and a chopping signal for chopping a predetermined control signal of the control signal, and the chopping unit. The control signal (for example, H level) is chopped by the signal, and the switching element U of the inverter unit 2
and a driver unit 5 for driving a, Va, Wa, Xa, Ya, and Za.

In the controller for the brushless motor 1, the energization of a plurality of armature windings of the brushless motor 1 is switched based on the position detection signals Ub, Vb, Wb of the rotor 1a, and the same applied voltage is applied. The rotor of the brushless motor is variably controlled to rotate at a predetermined rotation speed.

The voltage applied to each armature winding of the brushless motor 1 also changes depending on the ON / OFF ratio (command PWM ON time and command PWM OFF time) of the chopping signal from the control unit 4, that is, PWM control. The rotation speed of the brushless motor 1 in the method also varies depending on its command PWM on-time (and command PWM off-time).

Therefore, the rotation speed of the brushless motor 1 is calculated based on the position detection signal, and when the calculated rotation speed is different from the target rotation speed, the command PWM ON time (and the command PWM OFF time) is changed, that is, The on / off ratio of the chopping signal can be varied to adjust the rotation speed of the brushless motor 1 to the target rotation speed.

[0006]

However, when the brushless motor 1 is used as a compressor motor of an air conditioner, the load torque of the compressor fluctuates periodically as shown in FIG. There is a problem that the rotation of No. 1 during one rotation is not smooth, and thus periodical vibration and noise are generated, and the piping of the air conditioner is adversely affected.

In this structure, the compressor sucks the refrigerant, compresses it, and discharges it. The load torque is maximum during compression during one cycle of suction, compression, and discharge, and the compressed refrigerant is discharged. This is because the torque of the brushless motor 1 is linear, while the load torque becomes the smallest at the moment.

The present invention has been made in view of the above problems, and an object thereof is to smooth the rotation of a brushless motor, suppress vibrations and noises, and adversely affect the piping of an air conditioner. It is an object of the present invention to provide a brushless motor control method and an apparatus therefor capable of suppressing the above.

[0009]

To achieve the above object, in the present invention, the position of the rotor of a brushless motor is detected and the brushless motor is detected based on the detected position signal (position detection signal). When controlling the rotation of the rotor of the brushless motor by switching the energization of a plurality of armature windings of the motor, the load torque of each section of a plurality of sections obtained by dividing one cycle (one rotation) of the rotor The voltage applied to each armature winding is corrected according to the variation pattern, and the voltage applied to each armature winding can be adjusted.

[0010]

With the above means, the DC power supply is switched by the inverter means and applied to the armature winding of the brushless motor, and when the brushless motor is rotationally controlled by the PWM control method, a control signal for driving the inverter means is supplied. Chopping is performed with a chopping signal of a predetermined cycle, but PW of that cycle is obtained for each section obtained by dividing one cycle (one rotation) of the rotor.
The M on-time (and the PWM off-time) is changed according to the change of the load torque.

As a result, the voltage applied to the armature winding of the brushless motor is adjusted during one rotation according to the variation pattern of the load torque, and the torque of the brushless motor is changed according to the variation pattern of the load torque.

For example, the torque of the brushless motor is increased in the section where the load torque is large, and conversely, the torque of the brushless motor is decreased in the section where the load torque is small. Therefore, the rotation of the brushless motor is smoothed regardless of fluctuations in the load torque, vibration and noise are suppressed, and the piping of the air conditioner is not adversely affected.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A brushless motor control method and apparatus according to the present invention divides one cycle (one rotation) of a rotor of a brushless motor into a plurality of sections based on a detection signal of the position of the rotor of the brushless motor. In addition, the voltage applied to the armature winding of the brushless motor is corrected, that is, the applied voltage of the armature winding is corrected according to the fluctuation of the load torque. With this correction,
The applied voltage is increased to increase the torque of the brushless motor as the load torque increases, and conversely the applied voltage decreases to decrease the brushless motor torque as the load torque decreases.

Therefore, the controller of the brushless motor of the present invention has the structure shown in FIG. In the figure, the same parts as those in FIG.

In FIG. 1, this control device uses data (at least a command) corresponding to a variation in load torque for each section obtained by dividing one cycle (one rotation) of the rotor 1a of the brushless motor 1 into a predetermined number (for example, 12). It has a ROM (storage means) 6a for storing the correction data of the PWM on-time,
Based on the position detection signals Ub, Vb, Wb from the position detection unit 3, one rotation of the rotor 1a is divided into 12, and the data of the ROM (storage means) 6a is read out for each divided section to obtain the current command PWM. A controller (microcomputer) 6 for correcting and setting the on-time (and the current command PWM off-time) and outputting a chopping signal according to the corrected and set PWM on-time (and the PWM off-time) to the driver 5 is provided. There is. The controller 6 has each function of the controller 4 shown in FIG.

Next, the operation and control method of the brushless motor controller having the above-mentioned structure will be described in detail with reference to the flow chart of FIG. 2 and the time chart of FIG.

First, the control unit 6, for example, operates the three-phase brushless motor 1 synchronously, and then rotates the brushless motor 1 to a target rotation speed based on the position detection signals Ub, Vb, Wb of the rotor 1a as in the conventional case. Control. The rotor 1a
The position of may be detected by using a Hall element provided inside the brushless motor 1.

At this time, one revolution of the brushless motor 1 is divided into 12 based on the position detection signals Ub, Vb and Wb (divided into rotation angles of 30 degrees), and the divided section m.
(1 to 12) is determined (step ST1). For example, the timing for each rotation angle of 30 degrees is obtained based on the rising and falling of the position detection signals Ub, Vb, Wb.

Subsequently, the ROM 6 according to the determined section m
The data Ttm of a is read (step ST2). Incidentally. The content of the ROM 6a is, for example, when the variation pattern of the load torque during one rotation of the rotor 1a is periodic as shown in FIG. 3A, the data Ttm of each section m is the periodic variation of the load torque. Corresponding to, and the data Ttm in the section m in which the load torque is large.
Is a positive value, and the data Ttm is a negative value in the section m in which the load torque is small.

Subsequently, the switching elements Ua, Va, Wa, Xa, Ya, Za of the inverter section 2 are turned on in a predetermined manner.
Of the control signals to be turned off, for example, the switching element U
The command PWM on-time Tons (and command PWM off-time) of the chopping signal for chopping the H level of the a, Va, Wa control signals is corrected by the data Ttm read from the ROM 6a.

In this correction, data Ttm is added to the command PWM on-time Tons of the current chopping cycle to obtain PW.
While the M on time Ton is calculated, Ton is subtracted from the current chopping cycle Tc to calculate the PWM off time Toff (step ST3). The calculated PWM on time Ton and PWM off time Toff are set as data of the chopping cycle (step ST4). In addition,
The PWM on time Ton and the PWM off time Tof
The method of calculating f may be calculated in the previous section.

For example, section 3 where the load torque is the largest
(Rotation angle 60 to 90 degrees) and section 9 (rotation angle 240
(Degrees to 270 degrees), since the data Ttm read from the ROM 6a has the largest positive value, the PWM on time Ton of the chopping cycle becomes the largest and the PWM off time Toff becomes the smallest. As a result, the on time of chopping Ua, Va, Wa of the inverter unit 2 becomes long, so that the brushless motor 1
The voltage applied to the armature winding is increased, that is, the torque of the brushless motor 1 is increased.

On the contrary, the section 6 (rotational angle 150 ° to 180 degrees) and the section 12 (rotational angle 33) where the load torque is the smallest.
0 ° to 360 °), since the data Ttm read from the ROM 6a is the largest negative value,
The PWM on-time Ton of the chopping cycle is the shortest, and the PWM off-time Toff is the longest.
As a result, the on-time for chopping Ua, Va, Wa of the inverter unit 2 is shortened, so that the voltage applied to the armature winding of the brushless motor 1 is reduced, that is, the torque of the brushless motor 1 is reduced.

As for the other section m, the chopping cycle command P is adjusted in accordance with the variation of the load torque as described above.
WM on time Tons, command PWM off time is corrected,
The PWM on time Ton and the off time Toff are obtained, and the obtained PWM on time Ton and PWM off time Toff are set as the values of the current chopping cycle.

As described above, the control unit 6 controls the sections 1 to 1
PWM on time Ton, PW of chopping cycle for every 2
The M off-time Toff is varied according to the variation of the load torque, that is, the applied voltage of the armature winding of the brushless motor 1 is increased in a section where the load torque is large, and the applied voltage of the armature winding is set in a section where the load torque is small. Lower.

Therefore, the rotation during one rotation becomes smooth, and vibration and noise are suppressed, and when used as a compressor motor of an air conditioner, for example, during one cycle of refrigerant suction, compression and discharge operations. Rotation becomes smooth, periodic vibration and noise are suppressed, and adverse effects on piping etc. are suppressed.

Further, according to the brushless motor control method and the apparatus thereof of the present invention, the data for changing the PWM on-time of the control signal for driving the inverter means according to the variation pattern of the load torque is stored in the microcomputer. Since it is stored in a unit and realized by the microcomputer, there is an effect that no hardware is required, the cost is low, and the quality is good.

In the above embodiment, one rotation of the brushless motor 1 is divided into 12, but the number of divisions is not limited to this. For example, if the load torque changes intricately, the load torque is divided more, and if the load torque simply changes, the number of divisions (the number of sections) is decreased, and the data for each section is set to the complicated load torque. It may be determined in accordance with the fluctuation pattern of the above or a simple fluctuation pattern of the load torque.

As shown in FIG. 3, the load torque is 1
If repeated during rotation, the data T of the ROM 6a
The tm may be set to 6 (for example, the section m = 1 to 6) and repeatedly used.

[0030]

As described above, according to the present invention, the DC power is chopped by the inverter means and applied to the armature winding of the brushless motor, and the armature winding is energized based on the position detection of the rotor. A control method and apparatus for a brushless motor that performs switching to control the rotation of the brushless motor, wherein a cycle (one rotation) of the rotor is divided into a plurality of sections based on a detection signal of the position of the rotor of the brushless motor. The PWM on-time of the control signal for driving the inverter means is corrected for each section in accordance with the fluctuation of the load torque, and the larger the load torque is, the larger the applied voltage of the armature winding of the brushless motor is, On the contrary, since the applied voltage is made smaller in the section where the load torque is smaller, the rotation can be smoothed. In this case, the load torque fluctuates during one cycle of suction, compression, and discharge of the refrigerant, but smoothness of rotation can be achieved regardless of the fluctuation of the load torque, which in turn results in periodic vibration and noise of the compressor. This has the useful effect of suppressing the adverse effect on the piping and the like of the air conditioner.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a brushless motor control device according to an embodiment of the present invention.

FIG. 2 is a flow chart for explaining the operation of the control device shown in FIG.

FIG. 3 is a time chart type diagram for explaining the operation of the control device shown in FIG.

FIG. 4 is a schematic block diagram of a conventional brushless motor control device.

FIG. 5 is a load torque characteristic graph of a compressor when a brushless motor is used for the compressor.

[Explanation of symbols]

1 Brushless Motor (Brushless Motor) 1a Rotor 2 Inverter Section 3 Position Detection Section 4 Control Section 5 Driver Section 6 Control Section (Microcomputer) U, V, W Armature Winding Terminal Voltages Ua, Va, Wa Switching Elements ( Inverter part 2
Of) Ub, Vb, Wb position detection signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Ohara 1116 Suenaga, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Fujitsu General Limited

Claims (4)

[Claims] 1. A position of a rotor of a brushless motor is detected and a signal of the detected position (position detection signal) is detected.
When controlling the rotation of the rotor of the brushless motor by switching energization to a plurality of armature windings of the brushless motor based on the above, each section of a plurality of sections obtained by dividing one cycle (one rotation) of the rotor A method for controlling a brushless motor, wherein the applied voltage of each armature winding is corrected according to a variation pattern of load torque for each, and the applied voltage of each armature winding can be adjusted. 2. A DC power source is chopped by an inverter means and applied to a brushless motor, and current is applied to a plurality of armature windings of the brushless motor based on position detection (position detection signal) of a rotor of the brushless motor. A method of controlling a brushless motor that performs rotation control of the brushless motor by performing switching, wherein the rotation is performed for each of a plurality of sections obtained by dividing one cycle (one rotation) of the rotor based on the position detection signal. Child 1
Data for varying the command PWM on-time (and command PWM off-time) of the chopping cycle of the control signal for driving the inverter means during a cycle (one rotation) is stored. A storage means is provided, and the command PWM on-time of the chopping cycle is corrected in accordance with the variation of the load torque based on the data of the storage means for each section, and the applied voltage of each armature winding is adjusted. A method of controlling a brushless motor, which is characterized in that it is possible. 3. A DC power source is chopped by an inverter means and applied to a brushless motor, and current is applied to a plurality of armature windings of the brushless motor based on position detection (position detection signal) of a rotor of the brushless motor. In a controller for a brushless motor that performs switching to control the rotation of the brushless motor, the rotor of the rotor is divided into each of a plurality of sections obtained by dividing one cycle (one rotation) of the rotor based on the position detection signal. The command PWM on-time (and the command PWM off-time) of the chopping cycle of a predetermined control signal of at least the control signal for driving the inverter means is varied according to the variation pattern of the load torque during one cycle (one rotation). For storing the data for storing the command PWM on / off by the data in the storage means for each section. A control means for correcting the time according to the fluctuation of the load torque and driving the inverter means by a control signal including the corrected control signal is provided, and the applied voltage of each armature winding is adjusted. A brushless motor control device. 4. A microcomputer inputting a detection signal (position detection signal) of the position of a rotor of the brushless motor when controlling the rotation of the brushless motor by chopping a DC power supply by an inverter means and applying it to the brushless motor. Is a controller for a brushless motor that outputs a control signal for driving the inverter means to switch the energization of a plurality of armature windings of the brushless motor, wherein the microcomputer controls the rotor of the rotor based on the position detection signal. For each section of a plurality of sections obtained by dividing one cycle (one rotation), a command of the chopping cycle of a predetermined control signal of at least the control signal for driving the inverter means during one cycle (one rotation) of the rotor. PW
The storage unit internally stores data for varying the M on-time (and the command PWM off-time) in accordance with the variation pattern of the load torque, and the command is provided for each section by the data of the storage unit. The PWM on-time is corrected according to the fluctuation of the load torque, the inverter means is driven by the control signal including the corrected control signal, and the applied voltage of each armature winding during one rotation of the rotor is changed. A brushless motor control device characterized by being adjusted.