JP2000037058A - Motor controller using variable magnetoresistive position detector and temperature sensitive switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller which can detect the position of a motor and the temperature in the motor without increasing the number of signal lines for temperature detection, by collectively processing signals from a temperature-sensitive switch which detects the temperature in the motor and a position detector for rotor. SOLUTION: A motor controller 21 controls the position of a motor 22 by detecting the position of the rotor of the motor 22 by means of a demodulator 32 and a variable magnetoresistive position detector 23 to which high-frequency power is supplied. A temperature-sensitive switch 24 is set up in the main body of the motor 22 and, at the same time, connected in series with one side of the high-frequency power supplied to the detector 23 and the controller 21 protects the motor 22 from overheating by controlling the power supply to the motor 22 by detecting the actuation of the switch 24 from the level fluctuation of the output signal of the position detector 23.

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 using a variable reluctance type position detector and a temperature-sensitive switch, and more particularly, to controlling the position of a motor by detecting the position of a rotor by the position detector. And a device for arranging a temperature-sensitive switch on the motor body to monitor a temperature rise of the motor and protect the motor from overheating.

[0002]

2. Description of the Related Art FIG. 5 shows a block diagram of a conventional motor control device 1 of this type. According to FIG. 5, the position detector 3 of the rotor and the temperature-sensitive switch 4 are mounted on the motor 2, respectively. The position detector 3 and the position detection circuit 5 in the motor control device 1 The position of the rotor is detected, the position detection signal 6 is output to a control circuit 7 including a motor drive circuit in the control device 1, and the temperature-sensitive switch 4 and the temperature detection circuit 8 in the control device 1 are detected. With this, the motor 2
And outputs a temperature detection signal 9 to the control circuit 7 in the control device 1. The position detection signal 6 and the temperature detection signal 9 are separately processed by the control device 1 to control the position of the motor 2, and the motor 2 is protected from abnormal temperature rise. .

As the position detector 3, for example, there is a variable magnetic resistance type position detector, that is, a VR type resolver. The resolver 3 is coupled to the rotor of the motor 2 and supplied with high-frequency power to its winding, and outputs a two-phase sine wave signal (voltage) 3 having a 90 ° phase shift with respect to each other as rotor position information. Output.

On the other hand, as a motor with a built-in position detecting unit of the rotor, there is, for example, a two-phase DC motor 10 having a built-in position detecting unit shown in the sectional view of FIG. According to FIG. 6, the motor 10 includes a stator 11, a rotor 12,
A plurality (20 in the figure) of generating torque in the rotor 12
Motor winding portions 13 wound around the salient poles 15 respectively.
And a variable magnetoresistive position detector 14 composed of coils wound around a plurality of (four in the figure) salient poles 15 for detecting the rotor position of the rotor 12.

[0005] The stator 11 has a plurality (24 in the figure) of salient poles 15 arranged radially inward at an equal pitch angle. The rotor 12 is disposed on the central axis of the stator 11 such that an outer peripheral surface thereof faces the salient pole 15 via an air gap with an inner peripheral surface of the stator 11. 16 are rotatably supported by brackets and bearings (not shown). A plurality of (9 pairs, ie, 18 in the figure) permanent magnets 17 are provided on the outer peripheral surface.
However, the polarity is alternately repeated along the outer peripheral surface so as to face the salient pole 15.

[0006] Out of the 24 salient poles 15 of the stator 11, a winding for torque generation is wound around 20 salient poles 15, and two phases, ie, A phase, reverse A phase, and B phase are used. The motor winding portion 13 is formed so as to be connected to the phase B and the reverse B phase. The remaining four salient poles 15 of the stator 11 have
The rotor position detection coil is wound, and the position detection unit 14 is formed of two pairs of salient poles 15 connected to two sets of detection coil circuits.

The detecting section 14 is configured such that one of the two sets of detecting coil circuits is connected to the coils Sa and Sd wound around the first pair of the two pairs of salient poles 15, and the other is connected to the two sets of detecting coil circuits. Coils Sb and Sc wound around the second pair of the pair of salient poles 15
And each of the coils Sa, Sb, Sc, S
d is 75 degrees between the coils Sa and Sc (pitch angle for 5 salient poles), 90 degrees between the coils Sc and Sb (pitch angle for 6 salient poles), and 105 degrees between the coils Sb and Sd (7 pitch angles). The pitch between the coils Sd and Sa is 90 degrees (pitch angle for 6 salient poles), and is disposed on the stator 11. (JP
No. 62-244265 or Japanese Patent Publication No. 8-15387)

The position detecting section 14 comprises two sets of detecting channels, and the pair of coils Sa,
The rotor position detection signal is generated from the change in inductance of Sd and Sb, Sc.

[0009]

In the case of the motor control device 1, the motor 2 and the motor control device 1
As the number of signal lines between the motor 2 and the control device 1 decreases, the number of disconnection of the signal lines decreases, and the cost of the connection cable between the motor 2 and the control device 1 can be reduced and the reliability can be improved. However, in such a conventional motor control device 1, when a variable magnetoresistive position detector such as the rotor position detector 3 or the position detector 14 is used, four signal lines are used. In addition, there is a problem that a total of six signal lines are required for temperature detection.

Further, a position detection signal output from a position detector 3 connected to the rotor or a position detection unit 14 built in the motor 10 and a temperature-sensitive switch 4 for detecting the internal temperature of the motors 2 and 10 are used. There is a problem that the output temperature detection signal is not signal-processed in relation to the signal.

[0011] The present invention has been made in view of such a point,
The object of the present invention is to solve the above-mentioned problems, and to provide a signal from a temperature switch as a means for detecting the motor internal temperature and a position detector connected to the rotor or a position built into the motor as a position detection means for the rotor. A variable magnetoresistive position detector and temperature switch that can perform signal processing simultaneously with the position detection signal output from the detection unit and that can detect position and temperature without increasing the number of signal lines associated with temperature detection. It is to provide a motor control device to be used.

[0012]

In order to achieve the above object, the present invention provides a variable magnetoresistive position detector in which high-frequency power is supplied to a winding, and a demodulator. A motor control device that detects and controls the position of the motor is as follows.

A temperature-sensitive switch is provided on the motor body, and the temperature-sensitive switch is connected in series to one side of a high-frequency power supply to be supplied to the position detector, so that the operation of the temperature-sensitive switch is adjusted to the position. Sensing is performed based on a change in the output signal level from the detector, and the control device controls the power supply of the motor to protect the motor from overheating.

Also, a stator having a plurality of salient poles radially arranged inward at an equal pitch angle, a motor winding wound around each of the salient poles, and Disposed to face the salient pole via a peripheral surface and a gap,
A rotor having a plurality of permanent magnets whose polarity is alternately repeated along the outer peripheral surface, and a rotatably supported rotor,
A position (rotation angle) detection unit for the rotor, the detection unit having two sets of detection coil circuits, one of the circuits being:
The other circuit is connected to a coil wound around a first pair of salient poles, and the other circuit is connected to a coil wound around a second pair of salient poles. The magnetoresistive change (inductance change) has a phase difference of 180 degrees in electrical angle, and the two coils are arranged on the stator so that the phase difference of the rotor position (angle) signal is 90 degrees. A motor having a built-in rotor position detection unit comprising two sets of detection channels for generating a detection signal of the rotor position (rotation angle) from a change in magnetic resistance (change in inductance) of each of the paired coils. There, the position detection unit supplied with high-frequency power to the detection coil circuit, by a demodulator, to detect the position of the rotor,
In a motor control device for controlling the position of the motor,
It is as follows.

A temperature-sensitive switch is disposed on the motor body, and the temperature-sensitive switch is connected in series to one side of a high-frequency power supply to be supplied to the position detecting section, so that the operation of the temperature-sensitive switch is controlled by the position. Sensing is performed based on a change in the output signal level from the detection unit, and the control device controls the power supply of the motor to protect the motor from overheating.

Since the present invention is configured as described above, the temperature detecting switch for detecting the temperature inside the motor is connected to the rotor, or is included in the detection circuit of the position detecting unit built in the motor. And the signals from the temperature-sensitive switches are collectively or associated with the position detection signal and signal-processed, thereby enabling position detection and temperature detection without increasing the number of signal lines involved in temperature detection. Also,
Since a variable magnetoresistive resolver can be used as the position detector, it is inexpensive, has a small number of signal lines, and is easy to handle.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of a motor control device using a variable magnetoresistive position detector and a temperature-sensitive switch according to the present invention, and FIG.
FIG. 3 is a detailed control block diagram of the motor control device.

In FIG. 1, reference numeral 22 denotes a motor. The motor 22 has a variable magnetoresistive position detector (hereinafter referred to as a VR resolver) 2 as a position detector of the rotor.
3 is connected to the rotor, and a temperature-sensitive switch 24 is disposed inside the main body of the motor 22. The circuit of the VR resolver 23 includes the temperature-sensitive switch 24.
When the temperature-sensitive switch 24 does not operate (contact point: closed state), the VR type resolver 23 performs one rotation, for example, 50 cycles, and is 90 ° out of phase with each other as rotor position information. Output a two-phase sine wave signal (voltage).

The motor control device 21 uses the VR type resolver 23 and the temperature-sensitive switch 24 together with a detection unit 25 for detecting the rotor position, and the position detection signals Va1 and Vb1 output from the detection unit 25, so that the motor control unit 21 And a control unit 26 for controlling the position of the motor 22.

In the detailed control block diagram of the motor control device 21 shown in FIG. 2, the detection unit 25 of the motor control device 21 comprises a high frequency power supply circuit 31 and a demodulation circuit 32, and the control unit 26 It comprises a D conversion circuit 33, an arithmetic circuit 34, and a motor drive circuit 35.

The position detection coils L1, L2 to L4 in the VR resolver 23 have their sine wave-shaped inductance components depending on their positional relationship with the rotor. The coils L1 and L2, and L3 and L4, which are connected in series, are connected in parallel to each other to form a bridge circuit. Both ends of the bridge circuit are about 100 kHz output from the high-frequency power supply circuit 31. , And the position detection signals Va and Vb of the modulated wave are applied from the respective midpoints of the coils L1 and L2 and L3 and L4.
Is output.

The temperature-sensitive switch 24 is connected in series to one side of the high-frequency voltage supplied from the high-frequency power supply circuit 31 to the position detection coils L1 to L4 of the VR resolver 23. When the temperature of the main body of the motor 22 reaches the detected temperature, the contact is opened.

The rotor position detection signals Va and Vb output from the VR resolver 23 are
The demodulation circuit 32 performs synchronous demodulation together with the high-frequency power supply circuit 31 and outputs signals Va1 and Vb1 serving as sine and cosine functions of the detection position to an A / D conversion circuit 33 of the control unit 26. The position detection signals Va1 and Vb1 of the sine and cosine functions are supplied to the A / D conversion circuit 33.
Thus, the digital signals Va2 and Vb2 are converted into digital signals Va2 and Vb2. The arithmetic circuit 34 outputs a signal calculated as rotation angle information to the motor drive circuit 35. Next, the motor drive circuit 35 drives the motor 22 based on the rotation angle information signal to control the position of the motor.

Therefore, for each of the position detection coils L1 to L4 of the VR resolver 23, the relationship between the rotor position (rotation angle) θ and its inductance is as follows. Inductance of coil L1 = Lc + Lv · SINθ Inductance of coil L2 = Lc−Lv · SINθ Inductance of coil L3 = Lc + Lv · COSθ Inductance of coil L4 = Lc−Lv · COSθ (where Lc: constant inductance component, Lv: inductance change) component)

V output from the high frequency power supply circuit 31
When a high-frequency voltage represented by sinωt is applied to a bridge circuit in the VR resolver 23,
The following modulated wave voltage is output. Va = Vsinωt · (Lv / Lc) SINθ Vb = Vsinωt · (Lv / Lc) COSθ When this is synchronously demodulated, Va1 = KV · SINθ Vb1 = KV · COSθ (where K = Lv / Lc), and Position detection signals Va1 and Vb1 represented by trigonometric functions related to the rotor position are obtained. These signals are A / D-converted by an A / D conversion circuit 33, and then the rotation angle θ is obtained by the arithmetic circuit 34.
, The position of the motor 22 is controlled.

Next, when the temperature of the main body of the motor 22 rises and the temperature-sensitive switch 24 is operated to be in an open state, when the signal Va ', Vb '= Va' =-Vsin [omega] t Vb '=-Vsin [omega] t and a voltage on one side of the high-frequency voltage applied to the bridge circuit is output as it is.

The signal after the synchronous demodulation of the signals Va 'and Vb' is Va1 '=-V Vb1' =-V, and has a constant voltage irrespective of the rotation angle θ. By detecting such a voltage, it can be understood that the temperature of the motor 22 rises and the temperature-sensitive switch 24 operates.

The VR resolver 2 used in this embodiment
The ratio between the change component Lv of the inductance of each of the position detection coils L1 to L4 and the constant component Lc is 1
At approximately / 5, the signal level when the temperature-sensitive switch 24 is open is about five times larger than the signal level when the temperature-sensitive switch 24 is closed.

At the time of A / D conversion, the temperature-sensitive switch 24
Since it is more advantageous to improve the position detection accuracy when the signal amplitude when the switch is closed is full scale, the signal amplitude when the temperature sensitive switch 24 is open is limited by the full scale value. . Further, the signal level V between the closed state and the open state of the temperature-sensitive switch 24 after the A / D conversion.
When a2 is plotted on the horizontal axis and signal level Vb2 is plotted on the vertical axis, FIG.
It becomes as shown in.

In FIG. 3, the signals Va2 and Vb2 when the temperature-sensitive switch is closed are drawn as a sine function and a cosine function of the rotation angle θ, so that a circle is drawn, and the distance from the center is always constant. Va2 ', V2 when the signal is in the open state
b2 'becomes a limited value at full scale.

The signal V when the temperature-sensitive switch is closed
Assuming that the radius of the circle drawn by a2 and Vb2 is 1, the signals Va2 'and Vb2' when the switch is in the open state are at the position of √2 from the center. In order to determine whether or not the temperature-sensitive switch 24 has been operated, the determination value 設定 is set to 1 <χ <√2, and when √ (Va2 ² + Vb2 ² ) <χ, θ = t
Based on an ^-1 (Vb2 / Va2), the angle θ is obtained and position detection is performed. If {(Va2 ² + Vb2 ² )> χ, it is determined that the temperature-sensitive switch 24 is operating and appropriate overheating is performed. Provide protection.

FIG. 4 is a detailed control block diagram of the motor control device 21 showing a second embodiment of the present invention.
In FIG. 4, a conventional two-phase DC motor 10 and a variable magnetoresistive position detector 14 incorporated in the motor 10 as shown in FIG.
The same members as those in FIGS. 2 and 6 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 4, reference numeral 10 denotes a motor. The motor 10 has a built-in variable magnetoresistive type position detector 14 as a position detector of the rotor, and has a temperature-sensitive switch 24 connected to the motor. 10 are provided inside the main body.
In the circuit of the position detecting section 14, the temperature sensitive switch 24 is provided.
When the temperature-sensitive switch 24 does not operate, the position detection unit 14 performs a two-phase sine wave signal as rotor position information, which is rotated by 90 ° in one rotation, for example, in 18 cycles. (Voltage) is output.

Each pair of coils S of the position detector 14
a, Sd and Sb, Sc are called a sine coil pair and a cosine coil pair, respectively, and these coils Sa, S
d and between Sb and Sc, there is a phase difference of 180 degrees in electrical angle so that the inductance change becomes a differential coupling, and the two coil pairs Sa, Sd and Sb, Sc
Are formed such that the phase difference of the rotation angle voltage signal becomes 90 degrees. The position detection unit 14 is formed of two sets of detection channels for generating the detection signal of the rotor rotation angle from the inductance change of the pair of coils Sa, Sd and Sb, Sc.

The sine coil pair S of the position detector 14
The connection between a, Sd and the cosine coil pair Sb, Sc is as shown in FIG. 2 and is excited by a high frequency voltage of about 100 kHz output from the high frequency power supply circuit 31 of the position detection unit 25 in the motor control device 21. ing. The position detection signals Va and Vb at the middle points of the coil pairs Sa and Sd and Sb and Sc have the rotation angle θ of the motor rotor as one variable, and are given in the form of sine and cosine functions of the rotation angle θ, respectively. ing. Output from this midpoint,
The modulated wave position detection signals Va and Vb are output as described above.

The temperature-sensitive switch 24 is connected in series to one side of the high-frequency voltage supplied from the high-frequency power supply circuit 31 to the position detection coils Sa to Sd of the position detection section 14 in a normally closed state in which the switch is not operated. When the temperature of the main body of the motor 22 reaches the detected temperature, the contact is opened.

The rotor position detection signals Va and Vb output from the position detector 14 are signal-processed in the same manner as in the first embodiment.

Note that the technology of the present invention is not limited to the technology in the above-described embodiment, but may be implemented by means of other modes that perform the same function. Can be changed or added.
Further, in addition to the motor described in the embodiment of the present invention,
It is also applicable to linear (linear motion) motors and linear (linear motion) sensors.

[0039]

As is clear from the above description, according to the motor control apparatus using the variable magnetoresistive position detector and the temperature switch of the present invention, the temperature sensitive switch is disposed on the motor body, and A temperature switch is connected in series to one side of a high-frequency power supply that supplies the position detector, and the operation of the temperature-sensitive switch is sensed based on a change in the output signal level from the position detector, and the control device controls the temperature switch. Since the power of the motor is controlled to protect the motor from overheating, the output signal from the temperature switch is collectively output together with the output signal from the rotor position detector or the motor built-in rotor position detector. Performs signal processing without increasing the number of signal lines associated with temperature detection.
Position detection and temperature detection can be performed.

Therefore, even when an overheat protection function using a temperature detection switch is added to a motor having a position detection function, the number of signal lines and signal processing circuits need not be added.
Overheat protection can be performed, and an increase in cost and a decrease in reliability of the device due to the number of signal lines and addition of a signal processing circuit can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a motor control device using a variable magnetoresistive position detector and a temperature-sensitive switch according to the present invention.

FIG. 2 is a detailed control block diagram of the motor control device of FIG. 1;

FIG. 3 shows a state when a temperature-sensitive switch is not operated (closed state).
FIG. 9 is a diagram illustrating a Lissajous waveform of a position detection signal after A / D conversion, and also illustrates a state when a temperature-sensitive switch is operated (open state).

FIG. 4 is a detailed control block diagram showing a second embodiment of the motor control device of the present invention.

FIG. 5 is a configuration diagram showing a conventional motor control device using a position detector and a temperature-sensitive switch.

FIG. 6 is a configuration sectional view of a conventional motor with a built-in position detection unit.

[Explanation of symbols]

 1, 21 Motor control device 2, 22 Motor 3, 23 VR type resolver (position detector) 4, 24 Temperature sensitive switch 6, Va, Vb, Va1, Vb1 Position detection signal 10 Two-phase DC motor 14 Variable magnetoresistive position Detection unit 25 detection unit 26 control unit 31 high-frequency power supply circuit 32 demodulation circuit 33 A / D conversion circuit 34 arithmetic circuit 35 motor drive circuit

Claims (2)

[Claims] 1. A motor control device for detecting the position of a rotor and controlling the position of a motor by a variable magnetoresistive position detector in which high-frequency power is supplied to a winding and a demodulator, A switch is disposed on the motor body, and the temperature-sensitive switch is connected in series to one side of a high-frequency power supply for supplying the position detector, and the operation of the temperature-sensitive switch is output from the position detector. Sensing based on the change in signal level, controlling the power supply of the motor by the control device,
A motor control device using a variable magnetoresistive position detector and a temperature-sensitive switch, which protects the motor from overheating. 2. A stator having a plurality of salient poles radially inwardly arranged at an equal pitch angle, a motor winding wound around each of the salient poles, and A rotor, which is disposed so as to face the salient pole via a peripheral surface and a gap, has a plurality of permanent magnets whose polarity is alternately repeated along the peripheral surface, and is rotatably supported. And a position detection unit for the rotor, the detection unit having two sets of detection coil circuits, one of the circuits being a first of the salient poles.
Connected to a coil wound in pairs, the other said circuit
The coils wound around the second pair of salient poles are connected to each other, and each of the paired coils has a phase difference of 180 degrees in electrical angle in magnetoresistance change. Two sets of detection channels arranged on the stator so that the phase difference of the rotor position signal is 90 degrees, and generating the detection signal of the rotor position from the change in the magnetoresistance of the paired coils. A motor having a built-in rotor position detection unit consisting of: a position detection unit to which high-frequency power is supplied to the detection coil circuit; and a demodulator. In a motor control device for performing position control, a temperature-sensitive switch is provided in the motor body, and the temperature-sensitive switch is connected in series to one side of a high-frequency power supply to be supplied to the position detection unit, and the temperature-sensitive switch is switch The operation of is sensed based on a change in the output signal level from the position detection unit, and the control device controls the power of the motor,
A motor control device using a variable magnetoresistive position detector and a temperature-sensitive switch, which protects the motor from overheating.