JP2995919B2 - Motor speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor speed control device for quickly controlling a motor to a constant speed.

[0002]

2. Description of the Related Art In recent years, multi-functionality of audio equipment has been advanced, and high value-added motors mounted on these equipment have been demanded. In particular, regarding the speed control of the motor, it is required that the speed be controlled quickly and reliably to a constant speed, and various methods have been conventionally proposed. As a conventional technique of such a motor speed control device, for example, a predetermined reference speed is set, a motor speed is compared with a preset reference speed, and a difference between the motor speed control device and an acceleration command or a deceleration command is referred to. An error signal is output, the speed error signal is integrated using an integrating amplifier, and the output of the integrating amplifier is used as a torque command signal for varying the motor torque, so that the motor generates a torque proportional to the speed error. Controlling the speed of the motor by acting on it is one of the general methods. However, in such a speed control device, the DC amplification factor of the integrating amplifier is extremely large due to the configuration of the integrating amplifier, and the speed of the motor is significantly smaller than the reference speed, such as when the motor is started, and the speed that indicates an acceleration command is used. If the error signal continues to be input to the integrating amplifier, the output of the integrating amplifier easily saturates to the maximum or minimum value that the integrating amplifier can output. When the output of the integrating amplifier is saturated, a change in the output of the integrating amplifier with respect to a change in the speed error signal, that is, an input / output response of the integrating amplifier is extremely deteriorated. Since the output of the integrating amplifier is a torque command signal for varying the torque of the motor, if the input / output response of the integrating amplifier deteriorates, the torque generated in the motor can be changed immediately in response to a change in the value of the speed error signal. However, since the response of the motor to the speed error signal deteriorates, the speed of the motor is not easily stabilized at a constant speed equal to a preset reference speed. As a remedy for the above problems,
By providing a diode between the input and output of the integrating amplifier, even if the speed error signal continues to be input to the integrating amplifier and the output of the integrating amplifier decreases or increases, the change in the output does not exceed the ON voltage of the diode. . Since the output of the integrating amplifier is prevented from being saturated by being limited to the ON voltage of the diode, the input / output response of the integrating amplifier is improved, and the torque generated in the motor can be quickly varied in response to changes in the speed error signal. There is a conventional means that makes it possible to quickly stabilize the speed of the motor to a constant speed.

FIG. 3 shows a configuration diagram of a conventional motor speed control device. In FIG. 3, the input terminal of the motor 1 is connected to the output terminal of the motor driving means 2. 3
Is a speed detector, the output side of which is connected to one input side of the speed error signal generator 5. A first output of the speed error signal generator 5 is input to a first timer 9. The output of the first timer 9 is input to the second timer 10. The output of the second timer 10 is connected to the other input of the speed error signal generator 5. Here, the first timer 9
And the second timer 10 constitute the speed reference generator 4, the input of the first timer 9 forms the input of the speed reference generator 4, and the output of the second timer 10 4
Output. A second output of the speed error signal generator 5 is connected to a first input of the charge pump 6,
A third output of the speed error signal generator 5 is connected to a second input of the charge pump 6. Reference numeral 11 denotes a first constant current source, one of which is connected to the positive power supply line, and the other of which is the first constant current source.
Is connected to one of the switches 13. Reference numeral 12 denotes a second constant current source, one of which is grounded and the other is connected to one of the second switches 14. The other of the first switch 13 and the second switch 14 is commonly connected. Here, the components 11 to 14 constitute the charge pump 6, and the other common connection point CPO of the first switch 13 and the second switch 14 is on the output side of the charge pump 6. 15 is an amplifier, one input side of which is the first
And the other input side is connected to the output side of the charge pump 6 and to one of the resistors 17. The other side of the resistor 17 is connected to one side of the capacitor 18, and the other side of the capacitor 18 is
It is connected to the output side of the amplifier 15. Here, the components 15 to 18 constitute the integrating amplifier 7, and the amplifier 1
The other input of 5 forms the input of the integrating amplifier 7 and the output of the amplifier 15 forms the output of the amplifier 7. Reference numeral 19 denotes a diode. The anode of the diode 19 is connected to the input side of the integrating amplifier 7, and the cathode of the diode 19 is connected to the output side of the integrating amplifier 7. The output of the integrating amplifier 7 is input to the motor driving means 2. The output of the motor driving means 2 is input to the motor 1.

The speed of the conventional motor configured as described above is
The operation of the degree control device will be described with reference to the operation diagram of FIG.
Will be described. First, the speed of the motor is determined by the speed detector 3.
Detects and has a frequency proportional to the motor speed.
FG signal to be output. On the other hand, the speed reference generator 4
The first timer 9 and the second timer 10 that constitute
To generate a speed reference time T. A first timer 9 and
The second timer 10 runs from the start to the end of the timer.
Operating time at T₁, T_TwoThen T ₁+ T_TwoBut
The speed reference time T is set.

[0005] In FIG. 4, the speed detector 3 detects the time t =
t₀Input the falling signal to the speed error signal generator 5.
Power. The speed error signal generator 5 immediately generates the speed reference.
The first timer 9 constituting the container 4 is started. Times of Day
t = t₁, The first timer 9 ends and the second timer
Of the timer 10 is started. Time t = t_TwoTo become and
The second timer 10 ends. The second timer 10 operates
Immediately after the operation is completed, an acceleration command is sent to the speed error signal generator 5.
Outputs the desired speed error signal. Time t = t _Threebecome
And again the FG signal is the falling signal and the speed error signal generator
5, and the speed error signal generator 5 receives an acceleration command.
Stop the output of the desired speed error signal. That is, t =
t_TwoFrom t = t_ThreeUntil the speed error signal generator 5
Calculates a speed error signal indicating an acceleration command from the second output.
Output. Time t = t_ThreeThen, the first timer 9 is restarted.
And t = t_FourAnd the first timer 9 is terminated.
The second timer 10 starts, but the second timer 10
Before ending t = t_FiveThe FG signal indicates a falling signal
And the speed error signal generator 5 outputs a deceleration command from the third output.
Is output. And time t = t
₆When the second timer 10 ends, a speed error signal is generated.
Unit 5 stops outputting the speed error signal indicating the deceleration command
I do. That is, t = t_FiveFrom t = t₆Until the speed
The degree error signal generator 5 indicates a deceleration command from the third output.
Output a speed error signal. In this way, the speed error signal
Signal is output, the charge pump 6
Outputs a constant current in the reverse direction. That is, the speed error signal
When the generator 5 outputs a signal indicating an acceleration command,
Switch 1 which is one of the components of the energy pump 6
3 closes and outputs a constant current in the forward direction, meaning a deceleration command
When a signal is output, one of the components of the charge pump 6
The second switch 14 is closed and the constant current in the reverse direction is
Output. As described above, the period of the FG signal and the speed reference
Operation of first timer 9 and second timer 10 of creature 4
Time T = T₁+ T_TwoAnd output the time difference as a speed error signal
This method is generally widely known as a dual mono multi system.
Have been.

[0006] The speed error signal converted into a current by the charge pump 6 is integrated by an integrating amplifier 7. The output of the integrating amplifier 7 is used as a torque command as the motor driving means 2
The motor drive means 2 controls the torque generated by the motor 1 by varying the torque command in proportion to the magnitude of the speed error, and as a result, the time T generated by the speed reference generator 4 is obtained. = T ₁ + T ₂ and motor 1
The speed of the motor is controlled so that the cycle with the FG signal representing the speed of the motor coincides, that is, the speed error becomes zero.
That is, the speed of the motor 1 is equal to the reference speed N ₀ determined by the time T = T ₁ + T ₂ generated in the speed reference generator 4.
To be stabilized. The reference speed N ₀ is determined by the speed reference generator 4
Can be set arbitrarily by changing the time T = T ₁ + T ₂ that occurs in.

In the speed control of the motor described above, especially when the motor is started, the speed of the motor is significantly smaller than the reference speed, and a speed error signal indicating an acceleration command is continuously output. Is continuously input, the integrating amplifier 7 has a very large DC impedance in the feedback loop due to the configuration in which a capacitor and a resistor are provided in series between the input and output, that is, in the feedback loop. As a result, the DC amplification factor becomes extremely large. , The output tends to saturate easily to the maximum value or the minimum value that the integrating amplifier 7 can output, but by providing the diode 19 between the input and output of the integrating amplifier 7, the output of the integrating amplifier 7 than V _REF1, becomes a voltage value having a voltage difference drops below than the oN voltage V _bE of the diode da Ord 19 conducts and current output from the charge pump 6 flows into the output of the integrating amplifier 7 via the diode 19, decreasing small the output of the integrating amplifier 7 is stopped. That is, the output of the integrating amplifier 7 is turned on by the diode 19 based on the voltage V _REF1 of the bias power supply 16.
The voltage V _BE does not drop below the reduced value, the speed of the motor is significantly lower than the reference speed at the time of starting the motor, and a speed error signal indicating an acceleration command is continuously output. Even if the current continues to be input from the charge pump 6, the decrease in the output voltage of the integrating amplifier 7 is limited by the ON voltage V _BE of the diode 19, so that the output of the integrating amplifier 7 is not saturated, and to changes in the speed error, quickly torque command V _T by varying, varying the torque generated in the motor 1, the speed of the motor 1 rapidly can be controlled to a constant speed. The above operation is as shown in FIG.

[0008]

However, in the above-described conventional motor speed control device, a diode is used to restrict the reduction of the output voltage of the integrating amplifier, thereby preventing the output of the integrating amplifier from being saturated. The constraint level of the output of the integrating amplifier (hereinafter, the constraint level is referred to as a clamp level and the constraint is referred to as a clamp for simplicity of description) is limited by the ON voltage of the diode. It is difficult to arbitrarily and stably set the output clamp level without variation. In particular, when the motor speed control device is operated with a single dry cell, the potential of the positive power supply line that supplies power to the motor speed control device is extremely small at 1.5 V, and the clamping of the integrating amplifier is performed by the integrating amplifier. It is necessary to set the clamp level to a value obtained by subtracting 0.2 to 0.3 V from the bias power supply voltage. However, the ON voltage of the diode is 0.7V
Therefore, it is impossible to clamp the integrating amplifier using a diode. Therefore, the saturation of the output of the integrating amplifier cannot be prevented, and the input / output response of the integrating amplifier deteriorates, so that it is difficult to quickly stabilize the motor at a constant speed equal to a preset reference speed.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a motor speed control device that can quickly stabilize a motor at a constant speed equal to a preset reference speed even at an extremely low power supply voltage of one dry cell. It is intended for.

[0010]

In order to achieve this object, a motor speed control device according to the present invention comprises a motor, a motor driving means for generating torque to the motor, a speed detector for detecting the speed of the motor, and A speed reference generator that determines the speed reference of the motor, a signal representing the reference speed of the motor generated by the speed reference generator and the speed of the motor detected by the speed detector, and a speed difference, that is, a speed error A speed error signal generator that generates a signal indicating a speed error; a charge pump that outputs a forward or reverse current when the speed error signal generator generates a signal that indicates a speed error; and an integrating amplifier for integrating a current output, and a clamp circuit that constrains the output of the integrating amplifier between the input and output terminals of the integrating amplifier to a constant value, said clamping times The base of the first transistor
A bias power supply is connected, and the emitter is connected to the second transistor.
Connected to one of the emitter and one of the first constant current sources.
And the collector of the first transistor is connected to a third transistor.
With the collector of the transistor and the base of the fifth transistor
Commonly connected, the other of the first constant current sources is grounded,
The transistor 3 has its emitter connected to the positive feeder line.
And the base is the base and collector of the fourth transistor.
And a fourth constant current source.
The emitter of the transistor is connected to the positive feed line,
The other of the two constant current sources is grounded, and the second constant current source
The collector is connected to the positive feeder, and the base is connected to the fifth
At the collector of the transistor and at the output of the integrating amplifier
And the emitter of the fifth transistor is connected to the integration amplifier.
A motor speed control device connected to an input side of the width unit and configured to input an output of the integrating amplifier to the motor driving means.

[0011]

According to the present invention, not only the clamp level of the output of the integrating amplifier can be stably set arbitrarily without variation but also the speed control device of the motor can be a single dry battery, that is, 1.5V. Even when operating at an extremely low voltage, the integrating amplifier can be clamped, and the motor can be quickly stabilized at a constant speed equal to a preset reference speed.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of a motor speed control device of the present invention. FIG. 1 is the same as the conventional motor speed control device shown in FIG. 3 except that a clamp circuit 8 is provided between the input and output terminals of the integrating amplifier 7 in place of the diode 19 of the conventional example shown in FIG. It is. The configuration of the clamp circuit 8 will be described below. A second bias power supply 27 is connected to the base of the transistor 22, and the emitter is the emitter of the transistor 21 and the third bias power supply 27.
Is connected in common with one of the constant current sources 25. The collector of the transistor 22 is commonly connected to the collector of the transistor 23 and the base of the transistor 20. The other of the third constant current sources 25 is grounded. The emitter of the transistor 23 is connected to the positive supply line 23, and the base is commonly connected to one of the base and the collector of the transistor 24 and the fourth constant current source 26. The emitter of transistor 24 is connected <br/> the positive side feeder line. The other of the fourth constant current sources 26 is grounded. The collector of the transistor 21 is connected to the positive supply line, and the base is connected to the collector of the transistor 20 and the output of the integrating amplifier 7. Transistor 20
Are connected to the input side of the integrating amplifier 7. Here, the components 20 to 27 constitute the clamp circuit 8.

The G of the clamp circuit 8 configured as described above
In the path from the ND to the positive feeder line via the constant current source 26 and the transistor 24, the constant current source 26 is usually composed of a transistor. A corresponding voltage V _CE = 0.1-0.2V is required. Since the base and the collector are connected to the transistor 24, the collector-emitter voltage V _BE = 0.7 V of the transistor 24 is required. That is, the transistor 24 and the constant current source 26 can operate as long as the potential of the positive power supply line is V _CE + V _BE = 0.8 to 0.9 V or more. In other paths from the GND of the clamp circuit 8 to the positive feeder line, V _CE + V _BE = 0.8 to 0.9 V
There is no path that requires a potential that exceeds V. Therefore, the clamp circuit 8 sets the potential of the positive feeder line to V _CE + V _BE = 0.8-0.
Operation is possible with a voltage of 9 V or more. Even if one dry cell, that is, a power supply voltage of 1.5 V is used as the power supply of the positive-side power supply line, no problem occurs. The operation of the thus configured motor speed control device will be described with reference to FIG. First, the operation of the charge pump 6 for outputting a constant current in the forward or reverse direction according to the speed error signal is exactly the same as the operation of the conventional motor speed control device, and a description thereof will be omitted.

In FIG. 2, during a period from time t = t ₂ to t ₃ , a speed error signal generator 5 generates a speed error signal indicating an acceleration command and inputs the speed error signal to a charge pump 6. The charge pump 6 closes the first switch 13 and outputs a constant current I _AC generated by the first constant current source 11. The current I _AC output from the charge pump 6 is input to the integrating amplifier 7. Although the integrating amplifier 7 immediately reduces its output voltage because the DC amplification factor is extremely large,
Transistors 21 and 22 emitters are commonly connected to the base of the transistor 21 is input the torque command V _T is the output of the integrating amplifier 7, to the base of the transistor 22, the voltage V _REF2 of the second bias power supply 27 input When the value of V _T is larger than the value of V _REF2 , the transistor 21 is turned on and the transistor 22 is turned on.
Is turned off, so that transistor 20 is turned off. Further continuously input the I _AC to integrating amplifier 7, the value of V _T is smaller than the value of V _REF2, the transistor 21 is made from a conductive state to a non-conducting state, transistor 22 is rendered conductive from non-conductive state When a current larger than the current supplied from the collector of the transistor 23 is drawn into the collector of the transistor 22,
Current will be drawn from the base of transistor 20 so that transistor 20 will begin to conduct. When the transistor 20 is turned on, the I _AC input to the integrating amplifier 7 is immediately passed through the integrating amplifier 7 via the transistor 20.
And the output V _T of the integrating amplifier 7 decreases as
It will stay at V _REF2 . That minimum value of the output V _T of integrating amplifier 7 will be clamped to the value of the voltage V _REF2 of the second bias power supply 27 which is a component of the clamp circuit 8. Accordingly, the speed of the motor is significantly lower than the reference speed when the motor is started, and the speed error signal generator 5 inputs a signal indicating an acceleration command to the charge pump 6, and the charge pump 6 integrates the current I _AC . The torque command V _T, which is the output of the integrating amplifier 7,
Is without Waru falls below the V _REF2, the result integrating amplifier 7 saturation of the output is prevented, compared changes in the speed error, changing the torque generated quickly torque command V _T to the motor 1 to the variable Thus, the speed of the motor 1 can be quickly stabilized at a constant speed.

[0015]

As is apparent from the above description, the motor speed control device of the present invention is provided with a clamp circuit between the input and output terminals of the integrating amplifier, which is one of the components.
The output of the integrating amplifier is clamped to prevent the output from saturating, the torque command _VT is quickly changed in response to a change in the speed error signal, and the torque generated in the motor is quickly changed, so that the The speed can be quickly stabilized at a constant speed. Further, not only can the clamp level of the output of the integrating amplifier be arbitrarily and accurately set in advance, but also when the motor speed control device is operated with a single dry cell, that is, an extremely low voltage of 1.5 V, To realize a motor speed control device capable of quickly controlling the speed of the motor.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a motor speed control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of the motor speed control device according to the embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a conventional motor speed control device.

FIG. 4 is a diagram illustrating the operation of a conventional motor speed control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Motor drive means 3 Speed detector 4 Speed reference generator 5 Speed error signal generator 6 Charge pump 7 Integral amplifier 8 Clamp circuit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromitsu Nakano 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-61-228782 (JP, A) JP-A-63- 283484 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02P 5/00 G05B 11/42 G05D 13/62

Claims (1)

(57) [Claims] 1. A motor, motor driving means for generating a motor torque, a speed detector for detecting a speed of the motor, a speed reference generator for determining a reference speed of the motor, and a motor generated by the speed detector A speed error signal generator that compares a signal representing the speed of the motor and a signal representing the reference speed of the motor generated by the speed reference generator to generate a signal representing a speed error; and the speed error signal generator. Generates a signal representing a speed error, outputs a forward or reverse current, an integrating amplifier that integrates the current output by the charge pump, and the integration amplifier between the input and output terminals of the integrating amplifier. A clamp circuit for constraining the output of the amplifier to a constant value, wherein the clamp circuit has a bias power supply connected to the base of the first transistor and the emitter connected to the second transistor. The emitter of the transistor and one of the first constant current sources are commonly connected, and the collector of the first transistor is commonly connected to the collector of the third transistor and the base of the fifth transistor.
The other of the constant current sources is grounded, the emitter of the third transistor is connected to the positive power supply line, the base is commonly connected to one of the base and the collector of the fourth transistor, and the second constant current source. Emitter of transistor 4
It is connected to the positive side power supply line, the other of the second constant current source is grounded, the collector of the second transistor is connected to the positive side power supply line, based out of the collector and the integrating amplifier of the fifth transistor 5th transformer
The emitter of the transistor is connected to the input of the integrating amplifier.
Is, the speed control device for a motor that constitutes the output of the integrating amplifier to enter into the motor drive means.