JPH08149899A - Control device for rotating electric machine - Google Patents

Abstract

(57) [Abstract] [Purpose] In a control device for a rotating electric machine, a detection signal of a temperature detector is transmitted as a modulated signal by being superimposed on a DC power supply line. A sine wave output from a sine wave oscillator 17 is amplitude-modulated by a detection signal of a temperature detector 15 that detects the temperature of the motor, and the modulated signal is supplied to a DC power source for an encoder device 11 that detects the rotation state of the motor. Is superposed on the DC power supply lines 12a and 12b for supplying the signal via the pulse transformer 13. The modulated signal thus superimposed is demodulated by the demodulation circuit 17, and the control circuit 9 obtains the detection signal of the temperature detector 15. Further, the control circuit 9 and the encoder device 11
The low-pass filters 10 and 14 are interposed between the two so as not to be influenced by the modulated signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder device that outputs a pulse signal having a frequency proportional to the number of revolutions of a rotating electric machine and a rotating electric machine that performs control according to the output signal of a temperature detector that detects the temperature of the rotating electric machine. Control device.

[0002]

2. Description of the Related Art In the case of vector control of, for example, an induction motor as a rotating electric machine, parameters of the induction motor are obtained based on a pulse encoder device.
Since this parameter changes with temperature, it is necessary to detect and correct the temperature of the induction motor.

A conventional control device for such an induction motor is shown in FIG. The encoder device 1 attached to the rotary shaft of the induction motor (not shown) is supplied with DC power from the control circuit 2 through the DC power supply line 3, and the A-phase signal line 4, at the timing corresponding to the rotation speed of the induction motor. A pulse signal of each phase is output to the control circuit 2 via the B-phase signal line 5 and the Z-phase signal line 6. The control circuit 2 obtains the parameters of the induction motor based on these pulse signals and controls the rotation.

Temperature detector 7 for detecting the temperature of the induction motor
The detection signal of 1 is given to the control circuit 2 via the temperature detection signal line 8. The encoder device 1 and the temperature detector 7 are installed inside the induction motor, and the control circuit 2 that obtains these detection signals is provided.
Is usually installed at a position apart from the induction motor.
Therefore, the DC power supply line 3, the A-phase signal line 4, the B-phase signal line 5, the Z-phase signal line 6 and the temperature detection signal line 8 are laid over a relatively long distance.

[0005]

That is, in such a conventional configuration, in addition to the DC power supply line 3, the phase output signal lines 4, 5 and 6 of the encoder device 1, the temperature detection signal of the temperature detector 7 is detected. Since the wire 8 is required, the number of wires to be laid increases, the wiring work also increases, and there is a problem that the cost becomes high as a whole.

The present invention solves the above problems, and an object thereof is to transmit a detection signal of a temperature detection circuit by using a DC power supply line for supplying a DC power supply to an encoder device, and thereby to detect a temperature detection signal line. It is an object of the present invention to provide a controller for a rotating electric machine that can eliminate the above.

[0007]

In order to achieve the above object, a control device for a rotating electric machine according to claim 1 is an encoder device for outputting a pulse signal having a frequency proportional to the rotation speed of the rotating electric machine, and a rotating electric machine. A temperature detecting means for detecting a temperature, a DC power source to the encoder device via a DC power supply line, and a control means for controlling the rotary electric machine based on the output signal of the encoder device and the detection signal of the temperature detecting means, Modulating means for modulating the carrier wave by the detection signal of the temperature detecting means, superimposing means for superimposing the modulated signal output from the modulating means on the DC power supply line, and the encoder device side and the control means side of the DC power supply line, respectively. A low-pass filter provided to cut off the carrier wave and demodulation means for demodulating the modulated signal superimposed on the DC power supply line to obtain a detection signal of the temperature detection means are provided. It is an feature.

In this case, the modulation means may be configured to perform amplitude modulation (claim 2). In addition, the modulation means,
It may be configured to perform pulse width modulation (claim 3). Further, the modulating means may be provided with a reference signal giving means for giving a reference signal instead of the detection signal of the temperature detecting means (claim 4).

[0009]

According to the controller of the rotary electric machine of claim 1,
The modulated signal obtained by modulating the carrier wave with the detection signal of the temperature detecting means is superimposed on the DC power supply line that supplies the DC power supply to the encoder device. Since the detection signal of the temperature detection means obtained by demodulating the superimposed modulated signal is given to the control means, the conventional temperature detection signal line becomes unnecessary.

In this case, if the modulation means is configured to perform amplitude modulation, the modulation can be easily performed (claim 2). Further, even when the modulating means is configured to perform pulse width modulation, the same operational effect as in claim 2 can be obtained (claim 3).

Further, if the modulating means is provided with a reference signal giving means for giving a reference signal instead of the detection signal of the temperature detecting means, the output of the modulating means when the reference signal is given to the modulating means is demodulated. Demodulation by the control means, and by using the demodulated output as a reference value,
It is possible to eliminate the adverse effect on the signal due to the impedance of the DC power supply line which is the transmission path of the modulated signal (claim 4).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 showing the electrical configuration centering on the DC power source portion, the output terminal of the encoder device DC power source 9a of the control circuit (control means) 9 configured by a microcomputer or the like is provided near the control circuit 9. Via the low pass filter 10, it is connected to DC power supply lines 12 a and 12 b for supplying DC power to the encoder device 11.

The DC power supply lines 12a and 12b are laid so as to extend in the direction in which an induction motor (hereinafter simply referred to as a motor) as a rotating electric machine (not shown) is installed. On the motor side, the DC power supply line 12a is
It is connected to one input terminal of the low-pass filter 14 via the secondary winding 13S of the pulse transformer (superimposing means) 13, and the DC power supply line 12b is directly connected to the other input terminal of the low-pass filter 14. There is. And
The output terminal of the low-pass filter 14 is connected to the power input terminal of the encoder device 11 attached to the rotary shaft of the motor.

The temperature detector (temperature detecting means) 15 attached to the armature winding to detect the temperature of the armature winding as the temperature of the motor is composed of, for example, a thermistor. The terminal of is connected to one terminal of a sine wave oscillator 17 that outputs a sine wave as a carrier wave via a voltage dividing resistor 16. The other terminal of the sine wave oscillator 17 is connected to the other terminal of the temperature detector 15, and the 1
The temperature detector 15 and the voltage dividing resistor 1 are connected through the secondary winding 13P.
6 is connected to the connection terminal Pm.

Further, the other terminal of the sine wave oscillator 17 is
It is also connected to the DC power supply line 12b as a common ground line. The temperature detector 15, the voltage dividing resistor 16 and the sine wave oscillator 17 constitute an amplitude modulation circuit (modulation means) 18, which are arranged near the motor.

The DC power supply lines 12a and 12b are demodulation circuits (demodulation means) 19 provided near the control circuit 9.
Of the demodulation circuit 19, and the output terminal of the demodulation circuit 19 is connected to the input terminal of the control circuit 9. The above constitutes the motor control device 20.

Next, the operation of this embodiment will be described with reference to FIG. The encoder device 11 transmits the A-phase, B-phase, and Z-phase pulse signals to the control circuit 9 through a signal line (not shown) according to the rotation state of the motor, and the control circuit 9
Detects the parameters such as the rotation direction, rotation speed and phase of the motor based on the pulse signal, and performs vector control of the motor.

The sine wave oscillator 17 outputs a sine wave having a constant frequency and a constant amplitude as a carrier, as shown in FIG. 2 (a). The temperature detector 15 detects the temperature of the armature winding of the motor, and the resistance value decreases as the detected temperature rises. If a DC power source is provided instead of the sine wave oscillator 17, the divided voltage Vm detected at the connection terminal Pm is the operating time of the motor as shown in FIG. 2B. The temperature rises as the temperature of the motor rises over time.

That is, when the sine wave oscillator 17 outputs a sine wave, the divided voltage Vm is as shown in FIG.
The waveform of FIG. 2C is obtained by multiplying the voltage waveform of FIG. 2A by the voltage waveform of FIG. 2B, and the sine wave is amplitude-modulated according to the temperature detected by the temperature detector 15. .

The amplitude-modulated modulated signal flows through the primary winding 13P of the pulse transformer 13 and is induced on the secondary side. Therefore, between the DC power supply lines 12a and 12b,
A voltage waveform as shown in FIG. 2D in which the modulated signal is superimposed on the DC power supply voltage Vcc supplied to the encoder device 11 appears. However, since the control circuit 9 and the encoder device 11 have the low-pass filters 10 and 14 interposed therebetween, the modulated signal component thereof is blocked, so that the control circuit 9 and the encoder device 11 are not affected.

The demodulation circuit 19 is composed of, for example, an envelope demodulation circuit, and receives a DC power supply on which the modulated signal is superimposed as an input and demodulates a signal having a difference from the DC power supply voltage. , Its output is shown in FIG.
As described above, the signal detected by the temperature detector 15 according to the temperature of the motor appears as a DC signal. Then, the DC signal voltage is input to the control circuit 9, A / D-converted and input to the microcomputer, so that the control circuit 9 corrects the vector control according to the detected temperature of the motor.

As described above, according to this embodiment, the sine wave output from the sine wave oscillator 17 is amplitude-modulated by the detection signal of the temperature detector 15, and the control circuit 9 causes the encoder device 11 to operate via the pulse transformer 13. The modulated signal is superposed on the DC power supply lines 12a and 12b for supplying the DC power to and the demodulation circuit 19 demodulates the modulated signal to give the detection signal of the temperature detector 15 to the control circuit 9. The low-pass filters 10 and 14 are interposed between the control circuit 9 and the encoder device 11 so that the modulated signal does not affect them.

Therefore, unlike the prior art, the temperature detector 15
Since it is not necessary to provide a temperature detection signal line for obtaining the detection signal of 1) with the control circuit 9, the number of wirings can be reduced and reliability can be improved, and the time required for wiring work can be shortened. The cost can be reduced. Moreover, since the detection signal of the temperature detector 15 is made to be a modulated signal by the amplitude modulation circuit 18, the modulation can be easily performed with a simple configuration.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. In FIG. 3 showing the electrical configuration of the second embodiment, the connection terminal Pm
Is connected to the collector terminal of the NPN-type short-circuit transistor 21, and the other terminal of the temperature detector 15, that is, the common ground line (DC power supply line 12b) is connected to the emitter terminal of the short-circuit transistor 21. There is. The base terminal of the short-circuit transistor 21 is connected to the collector terminal of the NPN-type control transistor 23 via the base resistor 22.

The collector terminal of the control transistor 23 is connected via a pull-up resistor 24 to a DC power supply line 40 to which a DC power supply voltage Vcc supplied from the output terminal of the low pass filter 14 to the encoder device 11 is applied. Are connected, and their emitter terminals are connected to a common ground line.

The base terminal of the control transistor 23 is connected to the anode of the Zener diode 25, and the cathode of the Zener diode 25 is connected to the common ground line via the timer capacitor 26 and charged. It is connected to the DC power supply line 40 via the resistor 27 for use. A discharging resistor 28 is connected in parallel with the timer capacitor 26. The reference signal application circuit (reference signal application means) 29 is configured as described above, and the configuration in which the reference signal application circuit 29 is added to the configuration of the first embodiment constitutes the motor control device 30.

Next, the operation of the second embodiment will be described. When the control circuit 9 supplies the DC power to the encoder device 11 through the DC power lines 12a and 12b, the timer capacitor 26 is supplied via the charging resistor 27.
The charging starts at. At this time point, the control transistor 23 is in the off state because the potential of the base terminal thereof is at the low level, and therefore the short-circuiting transistor 21 is
Becomes a high level at its base terminal.

That is, the temperature detector 15 is the sine wave oscillator 1
When the sine wave output by 7 is a positive half-wave, a current flows from the collector terminal to the emitter terminal of the short-circuiting transistor 21 to cause a short circuit, and when it is a negative half-wave, the short-circuiting transistor 2
Even when 1 is in the ON state, the current from the emitter terminal to the collector terminal is substantially cut off, so that it is not short-circuited.

As a result, as shown in FIG. 2 (e), the positive half wave of the voltage Vm observed at the connection terminal Pm has a voltage drop due to the voltage dividing resistor 16 due to the amplitude of the sine wave output from the sine wave oscillator 17. The amplitude value of the negative half-wave is an asymmetrical waveform in which the amplitude of the sine wave is divided by the temperature detector 15 and the voltage dividing resistor 16.

At that time, the demodulation circuit 19 operates the DC power supply line 12
Since the signal level is output from the envelope of a positive half-wave obtained by rectifying the signal waveforms superimposed on a and 12b, the signal input to the control circuit 9 is a sine wave signal output from the sine wave oscillator 17 and is divided by a voltage. In addition to the resistance value of the resistor 16, the voltage drops due to the influence of the impedances of the DC power supply lines 12a and 12b, which are the transmission paths of the modulated signal.

Therefore, at this time, the signal given to the amplitude modulation circuit 18 serves as a reference signal, and the demodulated signal obtained by demodulating the modulated signal by the demodulation circuit 19 is used by the control circuit 9 for the temperature detector 15 thereafter. By correcting as the reference value when obtaining the detection signal, it is possible to remove the adverse effect of the impedance of the DC power supply lines 12a and 12b.

After that, when time elapses and the charging of the timer capacitor 26 is completed and the potential of the base terminal of the control transistor 23 becomes high level, the control transistor 23 is turned on and the base terminal of the short-circuit transistor 21. Becomes low level, the short-circuit transistor 21 is turned off. Then, the detection signal of the temperature of the motor by the temperature detector 15 in the normal state is superimposed and output on the DC power supply lines 12a and 12b. The subsequent operation is the same as in the first embodiment. The constant time during which the control transistor 21 is in the off state is determined by the time constants of the charging resistor 27 and the timer capacitor 26 and the Zener voltage of the Zener diode 22.

As described above, according to the second embodiment, the short-circuit transistor 21 is turned on for a certain period of time immediately after the control circuit 9 supplies the DC power to the encoder device 11, and the temperature detector is turned on. Short circuit 15 and temperature detector 1
Since the reference signal is supplied to the amplitude modulation circuit 18 instead of the detection signal of No. 5, the control circuit 9 uses the demodulated signal obtained at that time as the reference value, and uses the demodulated detection signal of the temperature detector 15 thereafter. By the correction, it is possible to eliminate the adverse effect on the modulated signal due to the impedance of the DC power supply lines 12a and 12b, which are the transmission paths, and it is possible to detect the temperature of the motor more accurately.

4 and 5 show a third embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. Comparator 31
The non-inverting input terminal of is connected to one output terminal of the triangular wave oscillator 32, and the other output terminal of the triangular wave oscillator 32 is
It is connected to the common ground line (DC power supply line 12b).

The inverting input terminal of the comparator 31 is connected to a connection terminal Pm 'which is a common connection point of the voltage dividing resistors 33 and 34 connected in series. The remaining terminal of the voltage dividing resistor 33 is connected to the DC power supply line 40, and the remaining terminal of the voltage dividing resistor 34 is connected to the common ground line via the temperature detector 15. Further, a Zener diode 35 is connected in parallel to the series circuit of the voltage dividing resistor 34 and the temperature detector 15.

The output terminal of the comparator 31 is connected to one terminal of the primary winding 13P of the pulse transformer 13, and the other terminal of the primary winding 13P is connected to the common ground line. The comparator 31, the triangular wave oscillator 32, the voltage dividing resistors 33 and 34, and the Zener diode 35 are used to form a pulse width modulation circuit (modulation means) 36.
And the demodulation circuit 19 is configured accordingly.
Instead of the above, a demodulation circuit 37 is provided, and a motor control device 38 is configured as described above.

Next, the operation of the third embodiment will be described with reference to FIG. The triangular wave oscillator 32 outputs a triangular wave Vt as shown in FIG. Further, the voltage Vm 'at the connection terminal Pm' shown in FIG. 5 (a) is also reduced when the temperature of the motor rises, so that the resistance value of the temperature detector 15 decreases and the partial pressure resistance value at the connection terminal Pm 'also decreases. As it does, it decreases accordingly.

Since the comparator 31 compares the voltage level of the triangular wave Vt with the voltage Vm 'as a reference and outputs the judgment result of its magnitude, its output waveform is shown in FIG. 5 (b).
The pulse waveform is as shown in. That is, the output waveform has a small pulse width when the temperature of the motor is low and the potential of the voltage Vm ′ is high, and the pulse width is large when the temperature of the motor is high and the potential of the voltage Vm ′ is low. The waveform has a pulse width modulated according to the temperature. The Zener diode 35 has a voltage Vm ′.
By limiting the maximum value of, the pulse width output from the comparator 31 is prevented from becoming a certain value or less.

The pulse-width-modulated signal is superimposed on the DC power supply line 12a via the pulse transformer 13 as in the first embodiment, and is applied to the input of the demodulation circuit 37. Here, in FIG. 5, the change of the voltage Vm ′ is shown extremely for the purpose of explanation, but in practice, the cycle of the triangular wave output from the triangular wave oscillator 32 is set sufficiently short as compared with the inclination of the temperature change of the motor. Therefore, if the pulse width of the modulated signal is detected, the pulse width directly corresponds to the temperature detected by the motor of the temperature detector 15.

However, the modulated signal induced on the secondary side of the pulse transformer 13 and transmitted by the DC power supply lines 12a and 12b includes the inductance of the secondary winding 13S and the line impedance of the DC power supply lines 12a and 12b. Causes the waveform to have a dullness as shown in FIG. Therefore, the demodulation circuit 37 shapes the waveform of the input modulated signal at a certain threshold value via an input buffer or the like, and then inputs the next pulse as a voltage value corresponding to the detected pulse width, for example. A circuit that holds and outputs the signal may be configured to demodulate the detection signal of the temperature detector 15. The subsequent operation is the same as in the first embodiment.

As described above, according to the third embodiment, the pulse width modulated signal is obtained by comparing the detection signal of the temperature detector 15 and the triangular wave output from the triangular wave oscillator 32 by the comparator 31. Since the width-modulated signal is superimposed on the DC power supply lines 12a and 12b via the pulse transformer 13 and demodulated by the demodulation circuit 37, the same effect as that of the first embodiment can be obtained.

FIG. 6 shows a fourth embodiment of the present invention.
The same parts as those in FIGS. 3 and 5 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. In FIG. 6, which shows the electrical configuration, a short-circuit for forming a reference signal application circuit 29 of the second embodiment in parallel with the temperature detector 15 incorporated in the pulse width modulation circuit 36 of the third embodiment. The collector terminal and the emitter terminal of the transistor 21 are connected to each other to form a motor control device 39.

Next, the operation of the fourth embodiment will be described. When the control circuit 9 supplies DC power to the encoder device 11 through the DC power supply lines 12a and 12b, the control transistor 23 is turned off for a certain period of time and the short-circuit transistor 21 is turned on, as in the second embodiment. Is turned on.

During the fixed time, the temperature detector 15 is short-circuited, and the inverting input terminal of the comparator 31 receives the divided voltage obtained by dividing the DC power supply voltage Vcc by the voltage dividing resistors 33 and 34. The divided voltage applied is
It becomes the minimum value because the voltage division resistance value shows the minimum. Therefore, the pulse width of the pulse width modulation signal output from the comparator 31 at that time shows the maximum value.

By the way, as described in the third embodiment, the modulated signal input to the demodulation circuit 37 includes the inductance of the winding of the pulse transformer 13 and the line impedance of the DC power supply lines 12a and 12b which are transmission lines. As a result, the waveform becomes dull, so that the pulse width is detected after the waveform is shaped by the input buffer. The degree to which the waveform is blunt varies depending on the impedance of the transmission path that is individually installed. Therefore, in order to accurately demodulate the detection signal of the temperature detector 15 from the pulse width of the modulated signal, the reference signal is the demodulation circuit 37. It is necessary to know how much the pulse width detected when input to is.

Therefore, while the above-mentioned short-circuiting transistor 21 is in the ON state, the signal supplied as the reference signal to the pulse width modulation circuit 36 instead of the detection signal of the temperature detector 15 is the DC power supply voltage Vcc divided. The divided voltage is divided by the resistors 33 and 34. Therefore, the control circuit 9
By using the signal demodulated from the modulated signal having the pulse width input to the demodulation circuit 37 at this time as a reference value,
The adverse effect on the modulated signal due to the impedance of the transmission path can be removed, and the detection signal of the temperature detector 15 can be detected thereafter. The operation after the short-circuiting transistor 21 is turned off after a certain time has passed is the same as in the third embodiment.

As described above, according to the fourth embodiment, by incorporating the reference signal giving circuit 29 into the pulse width modulation circuit 36, the control circuit 9 keeps constant power immediately after the DC power is turned on to the encoder device 11. During the time, the short-circuiting transistor 21 is turned on to short-circuit the temperature detector 15,
Since the reference signal is supplied to the pulse width modulation circuit 36 instead of the detection signal of the temperature detector 15, the modulated signal due to the inductance of the pulse transformer 13 and the impedance of the DC power supply lines 12a and 12b, which is the transmission path, is transmitted. The adverse effect can be removed and the detection signal of the temperature detector 15 can be detected, and the same effect as the second embodiment can be obtained.

The present invention is not limited to the embodiments described above and shown in the drawings, but the following modifications are possible. An induction motor is given as an example of the rotating electric machine, but other AC motors or DC motors may be used.
It can be a generator. Although the temperature of the armature winding is detected, the temperature of the field winding or the iron core, or the temperature of the refrigerant according to the ambient temperature or various cooling methods may be measured.

A thermistor is used as the temperature detector 15,
It may be a thermocouple. Although amplitude modulation and pulse width modulation are performed as the modulation means, the present invention is not limited to this, and frequency modulation or pulse phase modulation may be performed. Although the envelope detection is performed as the demodulation circuit 19, square detection may be used, and any point may be used as long as it demodulates the amplitude modulation signal.

[0050]

Since the present invention is as described above,
The following effects are obtained. According to the controller of the rotating electric machine of the first aspect, the modulated signal obtained by modulating the carrier wave by the detection signal of the temperature detecting means is superimposed on the DC power supply line for supplying the DC power to the encoder device. Since the detection signal of the temperature detection means obtained by demodulating from the superimposed modulated signal is given to the control means, the detection signal of the temperature detection means is transmitted to the control means by using the DC power supply line, Unlike the above, there is no need to separately provide a temperature detection signal line for obtaining the detection signal of the temperature detection means between the control means and the encoder device, the number of wiring lines can be reduced and the reliability is improved, and the time required for wiring work. Since it can be shortened, it is possible to reduce the cost as a whole.

According to the rotating electric machine control device of the present invention, the modulating means is configured to perform amplitude modulation.
The modulation can be easily performed. According to the control device for a rotating electric machine described in claim 3, since the modulation means is configured to perform pulse width modulation, the same operational effect as in claim 2 can be obtained.

According to the rotating electric machine control device of the present invention, the modulating means is provided with the reference signal giving means for giving the reference signal instead of the detection signal of the temperature detecting means.
By demodulating the output of the modulating means when the reference signal is given to the modulating means by the demodulating means and using the demodulated output as the reference value, the impedance of the DC power supply line that is the transmission path to the modulated signal The adverse effect can be removed, and the temperature of the rotating electric machine can be detected more accurately.

[Brief description of drawings]

FIG. 1 is a block diagram of an electrical configuration showing a first embodiment of the present invention.

[Fig. 2] Signal waveform diagram

FIG. 3 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 4 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 5 is a view corresponding to FIG.

FIG. 6 is a view corresponding to FIG. 1 showing a fourth embodiment of the present invention.

FIG. 7 is a diagram corresponding to FIG. 1 showing a conventional technique.

[Explanation of symbols]

9 is a control circuit (control means), 10 is a low-pass filter,
Reference numeral 11 is an encoder device, 12a and 12b are DC power supply lines, 13 is a pulse transformer (superimposing means), 14 is a low-pass filter, 15 is a temperature detector (temperature detecting means), 18
Is an amplitude modulation circuit (modulation means), 19 is a demodulation circuit (demodulation means), 20 is a control device, 29 is a reference signal application circuit (reference signal application means), 30 is a control device, and 36 is a pulse width modulation circuit (modulation means). ), 37 is a demodulation circuit (demodulation means), 38
Reference numerals 39 and 39 represent control devices.

Claims (4)

[Claims] 1. An encoder device for outputting a pulse signal having a frequency proportional to the rotation speed of a rotating electric machine, a temperature detecting means for detecting the temperature of the rotating electric machine, and a DC power supply to the encoder device via a DC power supply line. Control means for controlling the rotary electric machine based on the output signal of the encoder device and the detection signal of the temperature detection means, a modulation means for modulating a carrier wave by the detection signal of the temperature detection means, and the modulation means Superimposing means for superimposing the modulated signal output by the DC power supply line, a low-pass filter for blocking the carrier wave provided on the encoder device side and the control means side of the DC power supply line, and the DC power supply And a demodulation means for demodulating a modulated signal superimposed on the line to obtain a detection signal of the temperature detection means. Place. 2. The control device for a rotary electric machine according to claim 1, wherein the modulation means performs amplitude modulation. 3. The control device for a rotary electric machine according to claim 1, wherein the modulation means performs pulse width modulation. 4. The control device for a rotary electric machine according to claim 1, further comprising a reference signal giving means for giving a reference signal to the modulating means instead of the detection signal of the temperature detecting means. .