JPH0654572A - Heat protection apparatus for motor - Google Patents

Abstract

PURPOSE:To enable feeding a controller with protection signals by computing the winding temperature of a motor, detecting the flange temperature, estimating the winding and flange temperatures based on the thermal model of the motor through a state observer, and comparing the resultant values. CONSTITUTION:A parameter identifying device (PD) 32 identifies the winding resistance R of a motor 10 based on the winding voltage Va,k and Vb,k, and winding current ia,k and ib,k of A/D converters 25, 28 and 27, and the rotor angular velocity omegak, using the method of least squares. A parameter temperature converter (PC) 33 computes the winding temperature TR,K based on the identified winding resistance R in relation between winding resistance and winding temperature. A state observer 34 estimates the flange and winding temperatures of the motor 10 based on the thermal model of the motor 10, and subtracts the estimated values from the winding temperature TR,K computed by PC 33 and the flange temperature TC,K detected. A comparator 35 compares the differential temperature estimated by the state observer 34 and the threshold value, and feed a protection signal output device 37 with the result of the comparison.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat protection device for an electric motor.

[0002]

2. Description of the Related Art In heat protection of an electric motor, it is necessary to set an allowable temperature and a temperature rise limit according to a thermal insulator used in the electric motor, and operate the electric motor within the set temperature range. For this reason, as a heat protection device for the electric motor, a protective relay or a device having a temperature sensor installed inside the electric motor has been used.

However, when a heat relay is used, the protection operating point varies depending on the driving conditions and the external environment of the motor.
Further, since the internal temperature of the electric motor is not known, stable and accurate heat protection of the electric motor cannot be achieved. On the other hand, if a temperature sensor is installed inside, there are problems of increased cost and reduced reliability of the motor.

[0004]

DISCLOSURE OF THE INVENTION The first object of the present invention is to provide a thermal protection device for an electric motor, which is capable of performing optimum thermal protection in accordance with the temperature and other conditions of the electric motor.

A heat protection device for an electric motor according to a first aspect of the present invention is a motor control device including a controller for controlling an electric motor in response to a given command, wherein a current sensor for detecting a winding current of the electric motor, A temperature sensor for detecting the flange temperature, an angular velocity sensor for detecting the rotor angular velocity of the electric motor, a winding voltage applied to the electric motor by the controller, winding currents respectively detected by the current sensor and the angular velocity sensor, and Parameter identification means for identifying the winding resistance of the electric motor based on the rotor angular velocity, parameter temperature conversion means for determining the winding temperature of the electric motor based on the winding resistance,
The winding current and the rotor angular velocity respectively detected by the current sensor and the angular velocity sensor are input,
A state observer for estimating a flange temperature and a winding temperature of the electric motor using a thermal model of the electric motor including feedback of a temperature error, a flange temperature of the electric motor detected by the temperature sensor, and a flange estimated by the state observer. Comparison judgment means for judging abnormality of the electric motor based on flange temperature error with temperature, winding temperature error between winding temperature determined by the parameter temperature conversion means and winding temperature estimated by the state observer, And a protection signal output means for outputting a protection signal to the controller based on the judgment result from the comparison judgment means.

In a preferred embodiment of the first aspect of the invention, there is further provided display means for displaying the determination result from the comparison determination means and the winding temperature from the parameter temperature conversion means.

A heat protection method for an electric motor according to the first invention is
A controller for controlling an electric motor in response to a given command, a current sensor for detecting a winding current of the electric motor, a temperature sensor for detecting a flange temperature of the electric motor, and an angular velocity sensor for detecting a rotor angular velocity of the electric motor are provided. In the electric motor control device, the winding resistance of the electric motor is identified based on the winding voltage applied to the electric motor by the controller, the winding current and the rotor angular speed detected by the current sensor and the angular speed sensor, respectively. Then, the winding temperature of the electric motor is determined based on the identified winding resistance, and the winding current and the rotor angular velocity detected by the current sensor and the angular velocity sensor are input, and the estimated temperature error is fed back. The state estimation observer using the thermal model of the motor including The flange temperature and winding temperature of the machine are estimated, the flange temperature error between the flange temperature of the electric motor detected by the temperature sensor and the flange temperature estimated by the state observer, and the winding determined by the parameter temperature conversion means. Based on the winding temperature error between the line temperature and the winding temperature estimated by the state observer, the motor abnormality is judged, and based on the judgment result, a protection signal is output to the controller, and the controller outputs the protection signal. Accordingly, the control for protecting the electric motor is performed.

According to the first aspect of the invention, the winding resistance of the electric motor is identified, and the winding temperature is calculated from each of the identified resistances. The flange temperature is detected by a sensor. on the other hand,
Winding temperature and flange temperature are estimated by the state observer using the thermal model of the electric motor. Based on the estimated error between the detected or calculated temperature and the estimated temperature, the motor abnormality is judged and a protection signal is given to the controller.

In a preferred embodiment, the determined temperature is calculated as the abnormality of the motor.

Since the winding temperature of the electric motor can be calculated from the winding resistance, a winding temperature sensor is not required inside the electric motor, which leads to cost reduction and improvement of reliability of the electric motor. Moreover, since the thermal model of the normal state of the motor is used for the state observer, if any abnormality occurs in the motor regardless of the driving conditions and the external environment, one of the constant temperature errors becomes large, and the error at which temperature becomes. An abnormality of the electric motor can be detected depending on whether it has occurred. Therefore, stable and accurate protection of the electric motor is possible, and the electric motor can be used to the maximum extent.

Further, by displaying the abnormality determination result of the electric motor and the winding temperature, the user can know the abnormality of the electric motor.

A second aspect of the present invention, like the first aspect of the invention, aims to provide a thermal protection device for an electric motor, which is capable of optimal thermal protection in accordance with the temperature and other conditions of the electric motor.

A heat protection device for an electric motor according to the second invention is
In a motor controller including a controller that controls a motor in response to a given command, a current sensor that detects a winding current of the motor, a temperature sensor that detects a flange temperature of the motor, and a rotor angular velocity of the motor are set. The winding resistance and torque of the electric motor based on the angular velocity sensor for detecting, the winding voltage applied to the electric motor by the controller, and the winding current and rotor angular speed detected by the temperature sensor and the angular speed sensor, respectively. Parameter identifying means for identifying a constant, parameter temperature converting means for determining a winding temperature and a rotor temperature of the electric motor on the basis of the winding resistance and the torque constant, windings detected by the current sensor and the angular velocity sensor, respectively. Input the line current and rotor angular velocity, and State observer that estimates the flange temperature, winding temperature, and rotor temperature of the electric motor using the thermal model of the electric motor including feedback of the motor, and the flange temperature and the state observer of the electric motor detected by the temperature sensor. Flange temperature error from the flange temperature, winding temperature error between the winding temperature determined by the parameter temperature conversion means and the winding temperature estimated by the state observer, and the rotor temperature determined by the parameter temperature conversion means And a comparison judgment means for judging abnormality of the electric motor based on a rotor temperature error between the rotor temperature estimated by the state observer and a protection signal output to the controller based on the judgment result from the comparison judgment means. A protection signal output means is provided.

In a preferred embodiment of the second aspect of the present invention, there is further provided display means for displaying the determination result from the comparison determination means, the winding temperature and the rotor temperature from the parameter temperature conversion means.

A heat protection method for a motor according to a second aspect of the present invention is a controller for controlling the motor in response to a given command,
In a motor controller including a current sensor for detecting a winding current of the electric motor, a temperature sensor for detecting a flange temperature of the electric motor, and an angular velocity sensor for detecting a rotor angular velocity of the electric motor, the controller applies the electric current to the electric motor. Identifying means for identifying winding resistance and torque constant of the electric motor based on the winding voltage, the winding current and the rotor angular velocity detected by the current sensor and the angular velocity sensor, respectively, and the identified winding The winding temperature and the rotor temperature of the motor are determined based on the resistance and the torque constant, and the winding current and the rotor angular velocity detected by the current sensor and the angular velocity sensor are input, and the feedback of the temperature error is performed. Including a state observer using the thermal model of the above motor Flange temperature, winding temperature and rotor temperature of the electric motor are estimated, the flange temperature error between the flange temperature of the electric motor detected by the temperature sensor and the flange temperature estimated by the state observer, and the parameter temperature conversion means. The winding temperature error between the winding temperature determined by the above and the winding temperature estimated by the state observer, the rotor temperature determined by the parameter temperature conversion means, and the rotor temperature estimated by the state observer. Of the motor temperature is determined based on the rotor temperature error, the protection signal is output to the controller based on the determination result, and the controller controls the protection of the motor according to the protection signal. .

According to the second invention, the winding resistance of the electric motor,
The torque constant is identified, and the winding temperature and rotor temperature are calculated from the identified values. The flange temperature is detected by a sensor. On the other hand, the winding temperature, rotor temperature, and flange temperature are estimated by a state observer using a thermal model of the motor. Based on the error between the detected or calculated temperature and the estimated temperature, the motor abnormality is judged and a protection signal is given to the controller.

In a preferred embodiment, the determined motor abnormality and the calculated temperature are displayed.

Since the winding temperature and the rotor temperature of the electric motor can be calculated based on the winding resistance and the torque constant, the winding temperature sensor and the rotor temperature sensor are not required inside the electric motor. Therefore, the cost of the motor is reduced and the reliability is improved. In addition, since the state observer uses a thermal model of the normal state of the motor regardless of the driving conditions and the external environment, when an abnormality occurs in the motor, one of the temperature errors becomes large, and which temperature error occurs. The abnormality of the electric motor can be detected depending on whether it is done. Therefore, stable and accurate protection of the electric motor is possible, and the electric motor can be used to the maximum extent.

Further, by displaying the abnormality determination result of the electric motor and the internal temperature, the user can know the abnormality of the electric motor.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 shows a block diagram of a heat protection device for a motor according to a first invention having a controller for controlling the motor.

The heat protection device for this electric motor comprises a current sensor 2
1, angular velocity sensor 22, temperature sensor 23, temperature detection circuit 24,
A / D converters 25, 26, 27 and 28, parameter identification device
32, a parameter temperature conversion device 33, a state observer 34, a comparison / determination device 35, a protection signal output device 37, and a display device 36. The parameter identification device 32, the parameter temperature conversion device 33, the state observer 34, the comparison and determination device 35, etc. are realized by a programmed computer. The electric motor 10 is a three-phase motor, and each phase is represented by a, b and c. That is, each representing a phase current i _a, i _b and i _c, each phase voltage v _a, v _b and v _c. In FIG. 1, the estimated value is used by adding “hat” to the sign, but in the specification, it is used by adding () to the sign.

The controller 20 controls the electric motor 10 in response to a given command value according to a predetermined control algorithm. The controller 20 also controls the motor 10 to stop or perform a specific operation based on a protection signal from a protection signal output device 37 described later.

The heat protection device for the electric motor will be described below. The angular velocity ω of the rotor of the electric motor 10 is detected by the angular velocity sensor 23 and converted into a discrete value ω _k by the A / D converter 27. Further, the flange temperature T _C is detected by the temperature sensor 22 via the temperature detection circuit 24 and converted into a discrete value T _{C, k} by the A / D converter 26. A tacho generator or the like is used as the angular velocity sensor 23, and a thermocouple or the like is used as the temperature sensor 22. The winding voltages v _a and v _b applied to the electric motor 10 and the winding currents i _a and i _b detected by the current sensor 21 are the A / D converter 2 respectively.
5, 28 are converted into discrete values v _{a, k} and v _{b, k} , i _{a, k} and i _{b, k} . The subscript k indicates that the value is at the sample time k.

The parameter identification device 32 includes an A / D converter 25,
Winding voltage v _{a, k} and v _{b, k} from 28 and 27, winding current i
motor 10 based on _{a, k} and i _{b, k} and rotor angular velocity ω _k
The winding resistance R of is identified using the least squares method. In the least-squares method, the winding currents va _{, k} and vb _{, k} and the winding currents ia _{, k} and _{ib, k} are each converted into a rectangular coordinate transformation system of a two-phase stator, and then dq ( direct quadrature
) Converted winding voltage v _{d, k} and v _{q, k} , winding current i
_{d, k} and i _{q, k} are used.

When the winding voltage and the winding current of the electric motor 10 are dq converted, the relationship of the equation (1) is established in a steady state.

[0026]

[Equation 1]

Here, L _d and L _q are dq converted winding inductances of the motor.

From the equation (1), for the winding resistance R, time k =
It can be expressed by Eqs. (2) to (5) using the winding voltage, winding current, and rotor angular velocity detected from 1 to time k. However, ε is the error when Eq. (1) is expressed by Eqs. (2) to (5).

[0029]

[Equation 2]

The winding resistance R is calculated so as to minimize the error ε. That is, the winding resistance R is identified by the least squares method represented by the equation (5). The winding resistance R is identified at each time.

[0031]

[Equation 3]

Where Q is a weighting matrix.

The identified winding resistance R is given to the parameter temperature converter 33.

The parameter temperature conversion device 33 calculates the winding temperature T _R based on the winding resistance R identified by the parameter identification device 32 using the relationship between the winding resistance and the winding temperature. Equation (6) shows the relationship between winding resistance and winding temperature.

[0035]

[Equation 4]

Here, R ₀ is the resistance value at the temperature T _R0 .

Therefore, the resistance value R _{0 at the} temperature T _R0
If T is measured in advance, the temperature T _R can be calculated from the resistance value R using the equation (6).

Since the winding resistance R is identified by the parameter identifying device 32 at each time, the winding temperature T _R is also calculated at each time. The winding temperature T _{R, k} calculated at time k is given to the state observer 34.

The state observer 34 estimates the flange temperature and winding temperature of the electric motor 10 using the thermal model of the electric motor 10.
The state observer 34 is a motor heat model 34a and a subtraction circuit 34.
b, a gain circuit 34c. The thermal model of the motor can be expressed by Eqs. (7) to (9) when expressed in a continuous system. This allows the state observer to be expressed as in equation (10).

[0040]

[Equation 5]

Where A ₂ and B ₂ are constant matrices, λ _d and λ _q
Is the dq-converted magnetic flux. H ₂ is the feedback gain.

The input u ₂ of the thermal model of the equation (9) is Joule heat as the first element, eddy current loss as the second element, and friction heat due to motor shaft rotation as the third element.

The feedback gain H ₂ is calculated by the equations (11) to (1
Determined by 3).

[0044]

[Equation 6]

Here, σ ₁ and σ ₂ are predetermined poles.

From the equations (7) to (13), the estimation error e ₂ can be described by the following state equation.

[0047]

[Equation 7]

For example, when a cooling failure occurs, [1
The estimation error of the 0] ^T direction, that is, the flange temperature becomes large, and when the thermal insulation failure occurs, the estimation error of the [01] ^T direction, that is, the winding temperature becomes large.

The state observer 34 is realized by converting the equation (10) into a discrete value system. Parameter temperature converter
Winding temperature T _R from _{33, k} and the detected flange temperature T _C, estimated by the motor thermal model 34a from _k the winding temperature (T _{R, k)} and the flange temperature (T _{C, k)} is the subtraction circuit
Subtracted by 34b. The result of this subtraction, that is, the estimated temperature error e _{2, k} is fed back to the motor heat model 34a via the gain circuit 34c having a feedback gain. The estimated temperature error is also given to the comparison and determination device 35.

The comparison / determination device 35 compares the estimated temperature error from the state observer with the threshold value and gives the comparison result to the protection signal output device 37. In FIG. 2, the estimated value (T _{C, k} ) and the detected value T _{C, k} of the flange temperature are shown in (A1), and the estimated value (T _{R, k} ) and the calculated value T _R, of the winding temperature are shown in (A2) _. Examples of _k are shown respectively, and the corresponding flange temperature estimation error e _{C, k} is shown in (B1), and winding temperature estimation error e is shown in (B2).
_{R and k} are shown respectively. The same figure (A1), (A2)
In, the estimated value is shown by a broken line and the detected value or calculated value is shown by a solid line. The comparison / determination device 35 uses the estimation errors e _{C, k} , e
_{R, k} are compared with thresholds e _{C, th} and e _{R, th} , respectively. Figure 2
In section I of (B2), thermal insulation failure occurs, and during this period, the comparison / determination device 35 supplies a comparison output to the protection signal output device 37.

The protection signal output device 37 outputs a protection signal to the controller 20 based on the comparison output from the comparison / determination device 35. When this protection signal is given, the controller 20 stops the electric motor 10 or reduces the load factor to protect the electric motor.

On the other hand, the winding temperature TR _{, k} from the parameter temperature converter 33 and the comparison output of the estimation error from the comparison / determination device 35 are input to the display device. The display device 36 displays the winding temperature as the internal temperature and the abnormality of the electric motor 10 due to the cooling failure or the thermal insulation failure based on the comparison output. These displays include those shown in FIG.

In FIG. 3, an indicator 101 for displaying a winding temperature on a package 100 of a heat protection device for an electric motor, and an LED 102 for displaying a cooling failure or a thermal insulation failure, respectively.
, 103, and a connector 110 for connecting to a controller, a motor sensor, and the like. LED102
, 103 emit light when the estimation error exceeds a threshold and a comparison output is generated from the comparison and determination device 35, so that the user can know the abnormality of the electric motor.

Second Embodiment FIG. 4 is a block diagram of a heat protection device for an electric motor according to the second aspect of the invention, which is provided with a controller for controlling the electric motor.

The heat protection device for this electric motor comprises a current sensor 2
1, angular velocity sensor 22, temperature sensor 23, temperature detection circuit 24,
A / D converters 25, 26, 27, 28, parameter identification device 42,
A parameter temperature conversion device 43, a state observer 44, a comparison / determination device 45, a protection signal output device 47, and a display device 46 are provided. Parameter identification device 42, parameter temperature conversion device 4
3, the state observer 44, the comparison and determination device 45, etc. are realized by a programmed computer.

In FIG. 1, the same parts are designated by the same reference numerals and the description thereof will be omitted.

The heat protection device for the electric motor will be described below.

The parameter identifying device 42 identifies parameters such as winding resistance and torque constant based on the dq-converted winding voltage and winding current and rotor angular velocity by using the least square method. In the steady state of the motor, the relation of equation (1) is established, and as a result, from time k = 1 to time k
It can be expressed by Eqs. (16) to (19) using the winding voltage, winding current, and rotor angular velocity detected up to.

[0059]

[Equation 8]

As a result, the parameter P can be identified using the least squares method represented by the equation (20).

[0061]

[Equation 9]

The identified parameter P, that is, the winding resistance R and the torque constant K are given to the parameter temperature converter 43. The parameter P is identified at each time when the detected value is input.

The parameter temperature conversion device 43 calculates each temperature from the relationship between the parameter P identified by the parameter identification device 42 and the winding temperature T _R and the rotor temperature T _K. The relationship between parameters and temperature is expressed by equations (21) to (22).

[0064]

[Equation 10]

Here, f ₁ and f ₂ are functions of R and K, respectively.

For example, the winding temperature T _R can be calculated by transforming the equation (6) into the equation (21). Further, since the parameters are identified at each time, the temperature is also calculated at each time.

The state observer 44 estimates the flange temperature, the winding temperature and the rotor temperature using the thermal model of the electric motor 10. State observer motor thermal model 44a, subtraction circuit
44b and a gain circuit 44c. The thermal model of the motor can be expressed by equation (23) if it is expressed in a discrete value system. A state observer is formed using this thermal model.

[0068]

[Equation 11]

Where Φ ₃ and Γ ₃ are constant matrices, u _{3, k}
Is the heat source of the electric motor.

[0070] the state observer 44, winding temperature T _{R, k} and the rotor temperature T _K from the parameter temperature conversion device _{43, k,}
The detected flange temperature TC _{, k} and the winding temperature (TC _{, k} ), rotor temperature ( _{TK, k} ) and flange temperature (TC _{, k} ) from the motor heat model 44a are subtracted by the subtraction circuit 44b. The subtraction result, that is, the estimated temperature error is subtracted, and the gain circuit 44
It is fed back to the motor heat model 44a via c. The estimated temperature error is also given to the comparison / determination device 45.

The comparison / determination device 45 compares the estimated temperature error from the state observer 44 with a threshold value, and supplies the comparison output to the protection signal output device 47. The protection signal output device 47 outputs a protection signal to the controller 20 when an abnormality of the electric motor is determined by the comparison output from the comparison determination device 45.

On the other hand, the comparison output of the winding temperature and the rotor temperature from the parameter temperature conversion device 45 and the estimated temperature error from the comparison and determination device 45 are input to the display device 46. Display device
46 displays the abnormality of the motor based on the input temperature and comparison output.

[Brief description of drawings]

FIG. 1 is a block diagram showing a heat protection device for an electric motor according to a first embodiment.

FIG. 2 (A1) is an estimated value of flange temperature (T _{C, k} ) and a detected value T _{C, k} , and (A2) is an estimated value of winding temperature (T _{R, k} ).
And calculated values T _{R, k} , respectively, and (B1)
And (B2) are graphs showing the temperature errors corresponding to (A1) and (A2).

FIG. 3 is a diagram showing a package of a heat protection device for an electric motor.

FIG. 4 is a block diagram showing a heat protection device for an electric motor according to a second embodiment.

[Explanation of symbols]

 10 Motor 20 Controller 21 Current sensor 22 Angular velocity sensor 23 Temperature sensor 24 Temperature detection circuit 25, 26, 27, 28 A / D converter 32, 42 Parameter identification device 33, 43 Parameter temperature conversion device 34, 44 State observer 35, 45 Comparison judgment device 36,46 Display device 37,47 Protection signal output device

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G05B 17/02 7531-3H 23/02 302 V 7208-3H

Claims (6)

[Claims] 1. A motor controller including a controller for controlling a motor in response to a given command, comprising: a current sensor for detecting a winding current of the motor; a temperature sensor for detecting a flange temperature of the motor; and the motor. An angular velocity sensor for detecting the rotor angular velocity of the motor, the winding voltage applied to the electric motor by the controller, the winding current and the rotor angular velocity detected by the current sensor and the angular velocity sensor, respectively. Parameter identifying means for identifying winding resistance, parameter temperature converting means for determining winding temperature of the motor based on the winding resistance, winding current and rotor angular velocity detected by the current sensor and the angular velocity sensor, respectively. As input,
A state observer that estimates a flange temperature and a winding temperature of the electric motor by using a thermal model of the electric motor including feedback of a temperature error, a flange temperature of the electric motor detected by the temperature sensor, and a flange estimated by the state observer. A comparison judgment means for judging an abnormality of the electric motor based on a flange temperature error with respect to the temperature, a winding temperature error between the winding temperature determined by the parameter temperature conversion means and the winding temperature estimated by the state observer, and A heat protection device for an electric motor, comprising: a protection signal output means for outputting a protection signal to the controller based on a judgment result from the comparison judgment means. 2. The heat protection device for an electric motor according to claim 1, further comprising display means for displaying the determination result from the comparison determination means and the winding temperature from the parameter temperature conversion means. 3. A controller for controlling an electric motor in response to a given command, a current sensor for detecting a winding current of the electric motor, a temperature sensor for detecting a flange temperature of the electric motor, and a rotor angular velocity of the electric motor. In a motor control device including an angular velocity sensor, the motor based on a winding voltage applied to the motor by the controller, a winding current and a rotor angular velocity detected by the current sensor and the angular velocity sensor, respectively. The winding resistance of the motor is determined based on the identified winding resistance, and the winding current and rotor angular velocity detected by the current sensor and the angular velocity sensor are input. ，
The flange temperature and winding temperature of the electric motor are estimated by the state estimation observer using the thermal model of the electric motor including the feedback of the temperature error, and the flange temperature of the electric motor detected by the temperature sensor and the state observer are estimated. The abnormality of the electric motor is judged based on the flange temperature error with the flange temperature, the winding temperature error between the winding temperature determined by the parameter temperature conversion means and the winding temperature estimated by the state observer, and Based on the judgment result, a protection signal is output to the controller, and the controller controls the protection of the electric motor according to the protection signal. 4. A motor controller including a controller for controlling an electric motor in response to a given command, wherein a current sensor for detecting a winding current of the electric motor, a temperature sensor for detecting a flange temperature of the electric motor, and the electric motor. An angular velocity sensor for detecting the rotor angular velocity of the motor, based on the winding voltage applied to the electric motor by the controller, the winding current and the rotor angular velocity detected by the temperature sensor and the angular velocity sensor, respectively. Parameter identifying means for identifying winding resistance and torque constant, parameter temperature converting means for determining winding temperature and rotor temperature of the electric motor based on the winding resistance and torque constant, the current sensor and the angular velocity sensor, respectively. The detected winding current and rotor angular velocity respectively As input,
A state observer that estimates the flange temperature, the winding temperature, and the rotor temperature of the motor using the thermal model of the motor including the feedback of the temperature error, and the flange temperature and the state observer of the motor detected by the temperature sensor Flange temperature error from the measured flange temperature, winding temperature error between the winding temperature determined by the parameter temperature conversion means and the winding temperature estimated by the state observer, and the rotation determined by the parameter temperature conversion means. Comparison and determination means for determining abnormality of the electric motor based on a rotor temperature error between the child temperature and the rotor temperature estimated by the state observer,
And a protection signal output means for outputting a protection signal to the controller based on the judgment result from the comparison and judgment means. 5. The heat protection device for an electric motor according to claim 4, further comprising display means for displaying the determination result from the comparison determination means, the winding temperature and the rotor temperature from the parameter temperature conversion means. 6. A controller for controlling an electric motor in response to a given command, a current sensor for detecting a winding current of the electric motor, a temperature sensor for detecting a flange temperature of the electric motor, and a rotor angular velocity of the electric motor. In an electric motor control device including an angular velocity sensor, the controller of the electric motor based on the winding voltage applied to the electric motor by the controller, the winding current and the rotor angular velocity detected by the current sensor and the angular velocity sensor, respectively. Parameter identifying means for identifying the winding resistance and the torque constant, determining the winding temperature and the rotor temperature of the electric motor based on the identified winding resistance and the torque constant, respectively detected by the current sensor and the angular velocity sensor. Input winding current and rotor angular velocity
The flange temperature, winding temperature and rotor temperature of the motor are estimated by the state observer using the thermal model of the motor including the feedback of the temperature error, and the flange temperature of the motor and the state observer detected by the temperature sensor are used. Flange temperature error from the estimated flange temperature, winding temperature error between the winding temperature determined by the parameter temperature converting means and the winding temperature estimated by the state observer, and the parameter temperature converting means Based on the rotor temperature error between the rotor temperature and the rotor temperature estimated by the state observer, an abnormality of the electric motor is determined, and a protection signal is output to the controller based on the determination result, and the controller is protected. The heat protection of the motor, which controls to protect the motor according to the signal. Protection method.