JP2001145381A - Controller of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the torque of a brushless DC motor through simple constitution. SOLUTION: A controller 30 is provided with a rotational speed converting portion 32 that obtains the number of revolutions of a motor 10 from rotor positions detected by a resolver 22, and a phase adjusting portion 34 that adjusts the phase (angle of lead or angle of lag) of rectangular-wave signals outputted to the phases u, v, and w of the motor 10 based on the obtained number of revolutions. When the phase of a rectangular-wave signal is made to angularly lead or lag, the torque outputted from the motor 10 of the same number of revolutions is varied. Therefore, the torque of the motor 10 can be controlled by adjusting the phase. The controller only requires the adjustment of the phase of rectangular-wave signals and is simply constituted as compared with those which exercise motor torque control based on sine-wave PWM control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device, and more particularly, to a brushless DC motor using a rectangular wave signal.
The present invention relates to a control device for driving and controlling a motor.

[0002]

2. Description of the Related Art Conventionally, as a control device for a motor of this type, there is a device that estimates a rotor position from a magnetic pole position of a brushless DC motor, and drives and controls the motor by a sine wave PWM control with respect to the estimated rotor position. It has been proposed (for example, Japanese Patent Laid-Open No. 10-201284). In this device, the rotation speed is obtained from the interval between the edge signals of the magnetic poles of the brushless DC motor, and the rotor position is estimated by interpolation using the rotation speed, so that the motor can be driven without a detection sensor such as an encoder for detecting the rotor position. Drive control is possible.

[0003]

However, such a motor control device has a simplified structure in that a sensor for detecting the rotor position such as an encoder is not required, but the motor is driven by sine-wave PWM control. A control circuit is required, and electrical processing for the control is complicated.

As a method for simplifying the drive control of the motor, a method using a predetermined rectangular wave signal with respect to the electrical angle of the rotor has been considered. However, since a patterned rectangular wave signal is used, a pseudo sinusoidal signal is used. There is a problem that the characteristics of the motor cannot be sufficiently brought out as compared with the sine wave PWM control using a wave.

An object of the present invention is to control the motor torque with a simple configuration.

[0006]

Means for Solving the Problems and Their Functions and Effects The motor control device of the present invention employs the following means to achieve the above object.

A motor control device according to the present invention is a control device for driving and controlling a brushless DC motor using a rectangular wave signal, and controls an output characteristic of the motor by adjusting a phase of the rectangular wave signal. The gist of the present invention is to provide control means.

In the motor control apparatus according to the present invention, the output characteristics of the brushless DC motor are controlled by adjusting the phase of the rectangular wave signal by the control means. Since only the phase is adjusted, the configuration can be made simpler than that which performs the sine wave PWM control.

In the motor control device according to the present invention, the motor control device includes a state detecting means for detecting a state of the motor.
The control means may be means for adjusting the phase of the rectangular wave signal based on the state of the motor detected by the state detection means. In this case, the output characteristics of the motor can be controlled according to the state of the motor.

In the motor control apparatus according to the present invention, wherein the output characteristics are controlled based on the state of the motor, the state detecting means is means for detecting a rotational speed of the motor, and the control means is a means for detecting the rotational speed of the motor. Means for adjusting the phase of the rectangular wave signal based on the rotation speed of the motor. In the motor control device according to the aspect of the present invention, when the detected rotation speed of the motor is equal to or higher than a first predetermined rotation speed, the control means may determine a phase of the rectangular wave signal based on the rotation speed of the motor. Or the control means adjusts the rectangular wave signal based on the rotation speed of the motor when the detected rotation speed of the motor is equal to or less than a second predetermined rotation speed. May be a means for adjusting the phase to the retard side.

[0011]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a configuration diagram schematically showing the configuration of a control device 20 for a brushless DC motor according to an embodiment of the present invention. As shown in the drawing, the control device 20 for the brushless DC motor of the embodiment includes a rotor position (electrical angle θ) of the brushless DC motor 10 connected to the DC power supply 12.
And a controller 30 that controls a rectangular wave of a voltage applied to each of the u, v, and w phases of the motor 10 based on the detected rotor position.

The controller 30 is a hardware CPU.
And a plurality of switching elements (for example, switching elements forming a six-step inverter) for applying voltages of each phase of u, v, w, and are functionally functional. As shown in FIG. 1, a rotation speed conversion unit 32 for obtaining the rotation speed of the motor 10 from the rotor position detected by the resolver 22,
A phase adjusting unit 34 for advancing or retarding the phase of a rectangular wave signal as a standard output pattern based on the rotation speed obtained by the rotation speed conversion unit 32 is provided.

Next, the operation of the control device 20 for the brushless DC motor according to the embodiment configured as described above will be described. FIG. 2 is a flowchart illustrating an example of a motor control processing routine executed by the controller 30 of the control device 20 for the brushless DC motor according to the embodiment. This routine is repeatedly executed every predetermined time (for example, every 5 μsec) immediately after the start of driving of the motor 10.

When this routine is executed, the controller 30 first operates the motor 1 detected by the resolver 22.
Is read out (step S10).
0), the rotational speed Rev of the motor 10 is calculated by the following equation (1) using the read electrical angle θ (step S10).
2). Here, “Pole” in Equation (1) is the number of poles of the rotor.

[0015]

(Equation 1)

Subsequently, the calculated rotation speed R of the motor 10 is calculated.
A process of determining the phase of the rectangular wave signal based on ev is executed (Step S104). In the embodiment, the relationship between the rotation speed Rev and the phase of the motor 10 is obtained in advance through experiments and stored as a map, and the rotation speed Re of the motor 10 is stored.
Given v, a phase (leading angle or retarding angle with respect to the standard) corresponding to the rotation speed Rev is derived. FIG.
3 shows an example of a map illustrating the relationship between the rotation speed Rev of the motor 10 and the phase. FIG. 4 shows the rotation speed Re of the motor 10.
FIG. 4 is an explanatory diagram illustrating an example of a relationship between v, torque, and phase.
In FIG. 4, a solid line A shows the relationship between the rotation speed Rev and the torque when the standard output pattern illustrated in FIG. 1 is output without advancing or retarding the phase, and a solid line B shows the standard output pattern in FIG.
Is a relationship between the rotation speed Rev and the torque when a control output pattern (see FIG. 1) obtained using the phase determined by the map exemplified in FIG. ) Is the relationship between the rotation speed Rev and the torque when the phase is advanced by an angle and the torque is output. A broken line D indicates the rotation when the standard output pattern is output with the phase delayed by a predetermined angle (for example, 10 degrees). This is the relationship between the number Rev and the torque.

As shown in FIG. 4, when the rotation speed Rev is higher than the rotation speed R1, the motor 10 used in the embodiment obtains a larger torque than the case of outputting the standard output pattern by advancing the phase. Can be. Conversely, when the rotation speed Rev is less than the rotation speed R1, a larger torque can be obtained by retarding the phase than when outputting the standard output pattern. Therefore, by outputting the control output pattern obtained by advancing or retarding the phase using the map illustrated in FIG. 3, a larger torque can be obtained as compared with the case where the standard output pattern is always output. It is. Note that the relationship between the rotation speed Rev, the torque, and the phase is different depending on the motor used, and the torque control of the motor is determined by what kind of device the motor is used. It is determined according to the characteristics of the motor and the device using the motor.

When the phase (advance angle or retard angle with respect to the standard) is determined in step S104, the standard output pattern is set as the determined phase as a control output pattern, which is output (step S106). finish. When such a control output pattern is output, the switching elements corresponding to the u, v, and w phases are switched in this pattern, and the DC power supply 12 applies the voltage of this pattern to the u, v, and w phases of the motor 10. Is applied to control the torque of the motor 10.

According to the brushless DC motor control device 20 of the embodiment described above, the torque of the motor 10 can be controlled by adjusting the phase of the rectangular wave signal. In addition, since the phase of the rectangular wave signal is only advanced or retarded, the configuration can be simplified as compared with the case where the motor torque is controlled by the sine wave PWM control.

In the control device 20 for the brushless DC motor according to the embodiment, as shown in the map illustrated in FIG.
When the rotation speed Rev of 0 is larger than the rotation speed R1, the phase is advanced, and when the rotation speed Rev is smaller than the rotation speed R1, the phase is retarded.
Is larger than the rotation speed R1, the phase is advanced. However, when the rotation speed Rev is smaller than the rotation speed R1, the phase is not retarded.
Is smaller than the rotation speed R1, the phase is retarded. However, when the rotation speed Rev is larger than the rotation speed R1, the phase may not be advanced.

In the control device 20 for the brushless DC motor of the embodiment, the phase is advanced or retarded to increase the torque. However, the target torque of the motor 10 is set, and the set target torque is The phase may be advanced or retarded so as to be output from.

In the control device 20 for the brushless DC motor of the embodiment, the rotor position (electrical angle θ) is controlled by the resolver 22.
Can be directly detected, but may be a sensor capable of intermittently detecting the rotor position, such as a hall sensor installed at intervals of 60 degrees or 120 degrees. In this case, the interval time of the rise or fall of the signal detected by the Hall sensor is measured, the rotational speed Rev of the motor is calculated based on the measured interval time, and the electrical angle θ of the rotor is obtained complementarily. I just need.
FIG. 5 shows an example of the relationship between the Hall sensor output and the electrical angle.
As shown in the figure, the rotation speed Rev of the motor when the interval time is Tint is obtained by the following equation (2).
The rotor position when the time elapsed since the absolute position of each degree is determined is Tt is obtained by Expression (3).

[0023]

(Equation 2)

In the brushless DC motor control device 20 of the embodiment, the phase of the standard output pattern of the rectangular wave signal by the six-step inverter is advanced or retarded to control the motor 10.
The torque control of the motor is performed by advancing or retarding the phase of a pattern in which a part of a rectangular wave is duty-controlled in a comb-like manner as in the standard output pattern of the modification illustrated in FIG. May be performed.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically illustrating a configuration of a control device 20 for a brushless DC motor according to an embodiment of the present invention.

FIG. 2 is a control device 2 of the brushless DC motor according to the embodiment.
7 is a flowchart illustrating an example of a motor control processing routine executed by a controller 30 of No. 0.

FIG. 3 is an explanatory diagram showing an example of a map illustrating the relationship between the rotation speed Rev of the motor 10 and the phase;

FIG. 4 is an explanatory diagram showing an example of a relationship between a rotation speed Rev of the motor 10, a torque, and a phase.

FIG. 5 is an explanatory diagram illustrating a relationship between a Hall sensor output and an electrical angle.

FIG. 6 is an explanatory diagram illustrating a standard output pattern of a modified example.

[Explanation of symbols]

10 brushless DC motor, 12 DC power supply, 20
Control device for brushless DC motor, 22 resolver, 3
0 controller, 32 rotation speed converter, 34 phase adjuster.

Continued on the front page F term (reference) 5H560 BB04 DA02 DA10 DB20 EB01 EC02 RR10 SS01 TT15 UA10 XA06 XA12 XA15 5H575 BB10 DD06 DD10 HB02 HB20 JJ03 JJ25 LL01 LL31

Claims (5)

[Claims] 1. A control device for driving and controlling a brushless DC motor using a rectangular wave signal, the control device comprising: a control unit for controlling an output characteristic of the motor by adjusting a phase of the rectangular wave signal. apparatus. 2. The control device for a motor according to claim 1, further comprising: a state detection unit that detects a state of the motor, wherein the control unit is configured to detect a state of the motor based on the state of the motor detected by the state detection unit. A controller for controlling the phase of the rectangular wave signal. 3. The motor control device according to claim 2, wherein the state detection means is means for detecting a rotation speed of the motor, and the control means is configured to detect the rotation speed of the motor. A motor control device for adjusting a phase of the rectangular wave signal based on the control signal. 4. When the detected rotation speed of the motor is equal to or higher than a first predetermined rotation speed, the control means adjusts the phase of the rectangular wave signal to the advanced side based on the rotation speed of the motor. The motor control device according to claim 3, which is a means. 5. The control means, when the detected rotation speed of the motor is equal to or lower than a second predetermined rotation speed, adjusts the phase of the rectangular wave signal to a retard side based on the rotation speed of the motor. The motor control device according to claim 3 or 4, which is means.