JPH01291685A - Operation controller for dc motor - Google Patents

Abstract

PURPOSE:To suppress the rotational fluctuation of a rotor by controlling the input voltage of a DC motor in accordance with the amplitude of the output signal of a vibration pickup. CONSTITUTION:A frequency/voltage conversion circuit 18 generates a feedback signal Vf on the voltage level in proportion to the frequency of the output signal Va of a vibration pickup 15. A subtractor 20 supplies the deviated voltage between the reference signal Vs and the feedback signal Vf to a stator coil 3 through a DC amplification circuit 22. On the other hand, an amplitude detection circuit 23 detects the amplitude of the output signal Va of the vibration pickup 15 and gives it to an amplification factor regulation circuit 24. The amplification factor regulation circuit 24 changes the amplification factor of the DC amplification circuit 22 so that the larger the detected amplitude by the amplitude detection circuit 23 is, the less will the amplification factor be. In this way, cogging torque can automatically be reduced and the rotational fluctuation of a rotor can be suppressed accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an operation control device for a DC motor that improves the rotational characteristics of the DC motor.

(Prior Art) As an example of a DC motor operation control device, the input voltage of a DC motor is made to follow the deviation voltage between a feedback voltage signal corresponding to the rotational speed of the DC motor and a reference voltage signal corresponding to a set speed. There is a known system equipped with a constant speed control system that changes the speed by changing the speed.

In this case, the feedback voltage signal is obtained by obtaining a frequency signal proportional to the rotational speed of the DC motor by using a frequency generator, a magnetoresistive element, an optical encoder, etc., and converting this frequency signal into a voltage signal. That's what I do.

(Problems to be Solved by the Invention) -1; According to the conventional configuration described above, it is possible to rotate the DC motor at a constant speed at a set speed, but due to the cogging torque generated between the rotor magnet and the stator coil. There is a problem in that uneven rotation of the rotor cannot be avoided. In order to solve such problems,
Conventionally, an auxiliary circuit has been installed that suppresses the rotational unevenness described above by adjusting the input voltage of the DC motor, but in this case, a new element is required to detect rotational unevenness. This brings about a new problem in that the configuration of the auxiliary circuit becomes complicated.

The present invention has been made in view of the above circumstances, and its purpose is to suppress uneven rotation of the rotor caused by cogging torque, and to simplify the configuration for obtaining the effect of suppressing such uneven rotation. An object of the present invention is to provide a DC motor operation control device that makes it possible to do this.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides vibrations on the stator side of the flow motor so as to detect vibrations accompanying rotation of the rotor. In addition to fixing the pickup, an amplitude detection circuit for detecting the amplitude of the output signal of the vibration pickup is provided, and the input voltage of the DC motor is adjusted to increase the vibration of the DC motor in accordance with an increase in the detected amplitude by the amplitude detection circuit. A control circuit is provided to change the value in the direction of decreasing (
It consists of one component.

Also in this case, vibration pickup.

In addition to the amplitude detection circuit and the control circuit, there is also a speed setting circuit that generates a reference voltage signal corresponding to the set speed of the DC motor, and a feedback voltage signal that indicates the rotational speed of the DC motor based on the output signal of the vibration pickup. speed detection circuit,
Amplify the deviation voltage of the reference voltage signal and feedback voltage signal.
A constant speed control system is constructed by respectively providing a DC amplifier circuit that drives the DC motor by the amplified output thereof, and the control circuit adjusts the amplification factor of the DC amplifier circuit according to an increase in the detected amplitude by the amplitude detection circuit. may be configured to change in a direction that reduces vibrations of the DC motor.

(Function) When cogging torque is generated in the DC motor, the rotor vibrates due to the cogging torque.

Then, the amplitude detection circuit detects the amplitude of the vibration as described above through the vibration pickup fixed to the stator side, and the control circuit detects the inlet cuff of the DC motor according to the increase in the detected amplitude. 1 pressure is changed in a direction that reduces the vibration of the DC motor, thereby suppressing uneven rotation of the rotor.

Furthermore, even when a constant speed control system consisting of a speed setting circuit, a speed detection circuit, and a DC amplifier circuit is provided, the control circuit adjusts the amplification factor of the DC amplifier circuit (i.e., It changes the DC motor's input voltage (corresponding to the input voltage of the DC motor) in a direction that reduces the vibration of the DC motor, while suppressing uneven rotation of the rotor. Since the vibration pickup can also be used as an element for generating a signal (feedback voltage signal) indicating the rotational speed of the motor necessary for the constant speed control system, the configuration can be simplified.

(Example) An example of the present invention will be described below with reference to the drawings.

Figure 2 shows a brushless motor A, which is an example of a DC motor.
The configuration of the main parts is shown. In this figure 2, 1
1 is a stator support, which has a shape in which a shaft cylindrical portion 1b is integrally formed protruding from the center portion of a base portion 1a. Reference numeral 2 denotes an annular stator core fitted around the shaft cylindrical portion 1b, and a stator 4 is constructed by winding an IM 1i phase stator coil 3 around the annular stator core. Reference numeral 5 denotes a screw for fixing the stator core 2, and the screw 5 passes through the stator core 2 in the axial direction and is screwed onto the base portion 1a. In this case, the screw 5 is
It is configured to pass through a spacer 6 and a printed wiring board 7 arranged around the shaft cylinder portion 1b, and the stator core 2 is positioned in the axial direction by these spacers 6 and printed wiring board 7. Reference numeral 8 denotes a rotary shaft supported in the shaft cylindrical portion 1b via a bearing 9, and a rotor yoke 10 having a flat bottomed cylindrical shape is attached to the rotor yoke 10 by a screw 11.
are connected via etc. 12 is an annular rotor magnet that constitutes the rotor 13 together with the rotor yoke 10;
This is magnetized into multiple poles, and the rotor yoke 10
It is adhesively fixed to the inner surface of the peripheral wall of the stator core 2 so as to face the outer peripheral surface of the stator core 2 with a predetermined gap lj. 1
4 is 1 for the rotation of the rotor 13. This Hall element is arranged on the printed wiring board 7 so as to face the rotation locus of the rotor magnet 1-12.

Note that the number of Hall elements 14 corresponding to the number of phases of the stator coil 3 is provided. Although not shown, an energization control circuit including a Hall element 14 is provided on the printed wiring board 7'2, and this energization control circuit applies electricity to the stator coils 3 of each phase in a predetermined order. By energizing, rotational torque is generated between the stator coil 3 and the rotor magnet 12.

Now, reference numeral 15 denotes a vibration pickup using, for example, a piezoelectric element, which is fixed on the printed wiring board 7 provided on the stator 4 side, and is installed to detect vibrations accompanying the rotation of the rotor 13. It is being

Figure 1 shows a brushless motor A configured as described above.
The configuration of the energization control circuit shown in FIG. 1 is shown by combining only the parts related to the gist of the present invention using functional blocks. In FIG. 1, the output signal of the vibration pickup 15 is
It is outputted as a voltage signal Va via the amplifier circuit 16 and the waveform shaping circuit 17, and the frequency of the voltage signal Va changes in accordance with the rotational speed of the rotor 13. 1
8 is a frequency-voltage conversion circuit which is a speed detection circuit, and this is designed to generate a feedback voltage signal Vf having a voltage level proportional to the frequency of the -2 voltage signal Va (that is, the rotational speed of the rotor 3). , the feedback voltage signal Vf is applied to a subtracter 20 via a phase compensation circuit 19. 21 is a speed setting circuit that generates a reference voltage signal Vs of a voltage level corresponding to the set speed of the rotor 13;
s is provided to a subtractor 20. Here, the subtracter 20 calculates a deviation voltage (Vs
-Vf), and its deviation voltage (
Vs-Vf) is applied to the DC amplifier circuit 22. The stator coil 3 is energized by the amplified output of the DC amplifier circuit 22, and the stator coil 3 is energized.
As the input terminal of rotor 3 becomes higher, the rotational speed of rotor 3 also becomes higher.

In other words, the vibration pickup 15. A well-known constant speed control system that rotates the rotor 13 at a constant speed set by the speed setting circuit 21 is configured by a closed loop including the DC amplifier circuit 22, the stator coil 3, and the like. still,
The amplification factor of the DC amplifier circuit 22 is determined by an external signal: J3
It is configured so that it can be adjusted.

On the other hand, 23 is an amplitude detection circuit that detects the amplitude of the voltage signal Va, which is the output signal of the vibration pickup 15, and provides the detection result to the amplification factor adjustment circuit 24, which is a control circuit. This amplification factor adjustment circuit 24 adjusts the amplification factor of the DC amplification circuit 22 by
If the amplitude detected by the amplitude detection circuit 23 is large, it is configured to be changed so that it becomes smaller. Here, the amplitude of the voltage signal Va increases when the vibration of the rotor 13 is large. Therefore, when the vibration of the rotor 13 increases, the amplification factor of the DC amplifier circuit 22 is reduced and the amplitude of the stator coil 3 increases. Input terminal becomes low.

In short, according to the above (114), in a state where cogging torque is generated due to magnetic fluctuations between the stator coil 3 and the rotor magnet 12, the amplitude of the vibration of the rotor 13 due to the cogging torque is detected by the amplitude detection circuit 23 through the pickup 15. If the detected amplitude is large, the input voltage of the stator coil 3 is changed in the direction of lowering.As a result of this, the cogging torque and the vibration of the rotor 13 are reduced, and the cogging is reduced. The uneven rotation of the rotor 13 due to torque is suppressed. In this case, the output signal (voltage signal Va) of the vibration pickup 15 necessary for reducing the vibration of the rotor 13 described above is Since the speed signal originally required for the control system is also used, the overall configuration is simplified.

It should be noted that the present invention is not limited to the embodiment shown in the drawings, and may be modified in various ways without departing from the gist thereof, such as being applicable to DC motors other than brushless motors. It can be implemented by

[Effects of the Invention] As is clear from the above description, according to the present invention, the following effects can be achieved.

According to the DC motor operation control device of claim 1, a vibration pickup for detecting vibration accompanying rotation of the rotor and an amplitude detection circuit for detecting the amplitude of the output signal of the rotor detected by the vibration pickup are provided. The present invention has a configuration in which a control circuit is provided that changes the input voltage of the DC motor in a direction that reduces the vibration of the DC motor in accordance with an increase in the amplitude detected by the amplitude detection circuit, so that the cogging torque can be automatically reduced. As a result, uneven rotation of the rotor caused by cogging torque can be suppressed.

According to the DC motor operation control device of claim 2, in addition to the vibration pickup, amplitude detection circuit, and control circuit,
A speed setting circuit that generates a base voltage signal corresponding to the set speed of the DC motor, a speed detection circuit that generates a feedback voltage signal indicating the rotational speed of the DC motor based on the output signal of the vibration pickup, and the reference voltage signal. and a DC amplifier circuit that amplifies the deviation voltage of the feedback voltage signal and drives the DC motor with the amplified output thereof to constitute a constant speed control system, and the control circuit is configured to increase the detected amplitude by the amplitude detection circuit. Accordingly, the amplification factor of the DC amplification circuit is changed to an fM configuration in which the vibration of the DC motor is reduced, so that the vibration pickup used for suppressing uneven rotation of the rotor as described above can be used in a constant speed control system. The element can also be used as an element for generating a signal (feedback voltage signal) indicative of the rotational speed of the motor necessary for the operation, thereby simplifying the overall configuration.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention.
The figure is a block diagram showing the electrical configuration, and FIG. 2 is a longitudinal sectional view of the main parts of the DC motor. In the figure, A is a brushless motor (DC motor), 2 is a stator core, 3 is a stator coil, 4 is a stator, 7 is a printed wiring board, 12 is a rotor magnet, 13 is a rotor, 15 is a vibration hub, and 18 is a frequency - Voltage conversion circuit (speed detection circuit), 21 is a speed setting circuit, 22 is a DC amplifier circuit, 23 is an amplitude detection circuit, and 24 is an amplification factor adjustment circuit (control circuit). Applicant: Toshiba Co., Ltd. 11 Toshiba A blood flow motor Figure 2

Claims (1)

[Claims] 1. A vibration pickup fixed to the stator side of a DC motor so as to detect vibrations accompanying rotation of the rotor;
an amplitude detection circuit that detects the amplitude of the output signal of the vibration pickup; and a control circuit that changes the input voltage of the DC motor in a direction that reduces the vibration of the DC motor in accordance with an increase in the detected amplitude by the amplitude detection circuit. A DC motor operation control device comprising: 2. A vibration pickup fixed to the stator side of the DC motor to detect vibrations accompanying rotation of the rotor;
a speed setting circuit that generates a reference voltage signal corresponding to the set speed of the DC motor; a speed detection circuit that generates a feedback voltage signal indicating the rotational speed of the DC motor based on the output signal of the vibration pickup; and the reference. a DC amplifier circuit that amplifies the deviation voltage of the voltage signal and the feedback voltage signal and drives the DC motor with the amplified output; an amplitude detection circuit that detects the amplitude of the output signal of the vibration pickup; and a detected amplitude by the amplitude detection circuit. A control circuit for changing the amplification factor of the DC amplifier circuit in a direction that reduces vibrations of the DC motor in accordance with an increase in the DC motor.