JP7349879B2 - Motor control device, magnet temperature estimator, and magnet temperature estimation method - Google Patents

Description

The present invention relates to a motor control device including a magnet temperature estimator for estimating the temperature of a permanent magnet attached to a rotor of a motor, a magnet temperature estimator thereof, and a magnet temperature estimating method.

As a main motor in an electric vehicle, an embedded permanent magnet synchronous motor (PM motor) having a rotor equipped with a permanent magnet is frequently used.

It is generally known that permanent magnets demagnetize when exposed to high temperatures, and irreversible demagnetization occurs when the temperature exceeds a predetermined temperature. For this reason, there is a need for technology to detect the temperature of permanent magnets, but since the permanent magnets are embedded in the rotor, it is not possible to attach a temperature sensor to measure the temperature. Therefore, there is a need for a technology to estimate the temperature of a permanent magnet.

As a technique for estimating the temperature of a permanent magnet, there is a technique for estimating the temperature of a permanent magnet from the temperature of a PM motor coil or cooling oil (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2018-102102

In order to estimate the temperature of a permanent magnet, it is required to be able to estimate the temperature with high accuracy regardless of the operating state of the PM motor, and to be able to estimate the temperature using a simple method.

In the prior art described in Patent Document 1 mentioned above, the temperature of the permanent magnet is estimated by switching the estimation formula according to the operating state of the PM motor (rotation speed and torque of the PM motor). Therefore, it is necessary to adjust the constants of a plurality of estimation formulas in advance, which increases development cost and software processing load. Further, by reducing the number of estimation formulas, it is possible to suppress an increase in cost and an increase in software processing load, but there is a possibility that the temperature cannot be estimated with high accuracy.

The present invention has been made in view of the above problems, and its object is to provide a motor equipped with a magnet temperature estimator that can accurately estimate the temperature of the permanent magnet of the motor, although it has a simple configuration. An object of the present invention is to provide a control device, a magnet temperature estimator thereof, and a magnet temperature estimation method.

In order to solve the above problems, a motor control device according to the present invention includes a motor having a rotor to which a permanent magnet is attached, a stator to which a coil is wound, and a coil temperature detection unit for detecting the temperature of the coil. a cooling oil temperature detection section that detects the temperature of cooling oil that cools the motor; and a detection value of the coil temperature detection section and the detection value of the cooling oil temperature detection section to detect the temperature of the permanent magnet of the motor. a magnet temperature estimator for estimating a magnet temperature, the magnet temperature estimator having a first coefficient that changes according to a detection value of the coil temperature detection section, and a detection value of the cooling oil temperature detection section. The magnet temperature is estimated using a second coefficient that changes according to .

According to the present invention, although the configuration is simple, it is possible to estimate the magnet temperature of the motor with high accuracy.

Problems, configurations, and effects other than those described above will be made clear by the following description of the embodiments.

FIG. 1 is a configuration diagram of a motor control device in a first embodiment according to the present invention. FIG. 2 is a configuration diagram of a magnet temperature estimator in FIG. 1. FIG. FIG. 3 is a thermal circuit diagram showing a thermal equivalent circuit of the motor in this embodiment. FIG. 4 is a diagram showing the heat flow when the coil in FIG. 3 has a large calorific value and the temperature of the cooling oil is low. FIG. 4 is a diagram showing the heat flow when the coil in FIG. 3 has a large calorific value and the temperature of the cooling oil is high. FIG. 4 is a thermal circuit diagram showing the thermal resistance Roc in FIG. 3 by changes in Rom and Rcm. FIG. 3 is a configuration diagram of another example of the magnet temperature estimator of the first embodiment in which the input of the coil temperature function and cooling oil temperature function in FIG. 2 is the temperature difference between the coil and the cooling oil. FIG. 2 is a configuration diagram of a motor control device according to a second embodiment of the present invention. 9 is a configuration diagram of the magnet temperature estimator in FIG. 8. FIG. 10 is a configuration diagram of another example of the magnet temperature estimator of the second embodiment in which the input of the coil temperature function and cooling oil temperature function in FIG. 9 is the temperature difference between the coil and the cooling oil. FIG.

Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same reference numbers indicate the same components or components with similar functions.

[First embodiment]
FIG. 1 shows the configuration of a motor control device 800 in a first embodiment according to the present invention.

The motor control device 800 is mounted, for example, in a drive system of an electric vehicle, and includes a motor 300, a motor drive device 100, and a magnet temperature estimator 400.

Although not shown, the motor drive device 100 includes a computer (microcomputer) that includes a CPU (Central Processing Unit) that performs arithmetic processing, a memory that stores data, programs, and the like. In this embodiment, the motor drive device 100 includes a current detection section 120, a current control section 110, an inverter 130, and a current command generation section 140.

Battery 200 is a DC voltage source for motor drive device 100. The DC power stored in the battery 200 is converted by the inverter 130 of the motor drive device 100 into three-phase AC power of variable voltage and variable frequency. Inverter 130 supplies this three-phase AC power to motor 300.

The motor 300 is a synchronous motor that is rotationally driven by the supply of three-phase AC power. Note that as the motor 300, a permanent magnet synchronous motor is applied in this embodiment. The motor 300 includes a rotor 310, a rotation angle sensor 320, a stator 330, a coil 380 wound around the stator 330, a cooling oil 340, and a cooling oil temperature detection section that detects the temperature of the cooling oil 340. 350 and a coil temperature detection section 360 that detects the temperature of the coil 380.

A permanent magnet (hereinafter sometimes simply referred to as a magnet) is attached to the rotor 310, and is, for example, a neodymium magnet. Further, the motor 300 may be a surface magnet type motor in which permanent magnets are installed on the surface of the rotor, or may be an embedded magnet type motor in which permanent magnets are embedded in the rotor.

Furthermore, a resolver 320 is attached to the motor 300 as the rotation angle sensor in order to control the phase of the three-phase AC voltage in accordance with the phase of the induced voltage of the motor 300. Since the resolver 320 is composed of an iron core and a winding, it has excellent environmental resistance, but a GMR sensor or a sensor using a Hall element may be used as the rotation angle sensor.

A copper wire is wound around the stator 330 as a coil 380, and a temperature sensor is provided as a coil temperature detection section 360 for detecting the temperature of the coil 380. Although the temperature of the coil 380 is used in this embodiment, the temperature of the stator 330 may be detected and used as another method.

Motor 300 has cooling oil 340 to cool motor 300. The cooling oil 340 is circulated by a cooling oil pump 370 or the like to cool the motor 300. Further, a temperature sensor or the like is provided as a cooling oil temperature detection section 350 that detects the temperature of this cooling oil 340.

The motor drive device 100 has a current control function for controlling the output of the motor 300, but in this embodiment, so-called vector control is applied as follows.

The current detection unit 120 converts three-phase motor current values (Iu, Iv, Iw) detected by a current sensor (for example, CT (Current Transformer)) according to the rotation angle θ of the motor 300 detected by the resolver 320. and performs dq conversion, and outputs the dq-axis current detection values (Id, Iq). The current control unit 110 adjusts the dq-axis voltage so that the detected dq-axis current value (Id, Iq) matches the dq-axis current command value (Id*, Iq*) created by the current command generation unit 140. Create and output commands (Vd*, Vq*). Current command generation unit 140 receives a torque command for driving motor 300 from a higher-level control unit (not shown), and calculates dq-axis current commands (Id*, Iq*).

The inverter 130 converts the dq-axis voltage commands (Vd*, Vq*) into three-phase motor voltage commands (Vu*, Vv*, Vw*) according to the rotation angle θ, and converts the three-phase motor voltage commands into three-phase motor voltage commands (Vu*, Vv*, Vw*). A drive signal is created using pulse width modulation (PWM) as a modulated wave. By using this drive signal to turn on/off the semiconductor switching elements that constitute the main circuit in inverter 130, inverter 130 supplies three-phase voltages (Vu, Vv, Vw) to motor 300 in accordance with the motor voltage command. Output.

The magnet temperature estimator 400 receives the temperature of the coil 380 detected by the coil temperature detection section 360 and the temperature of the cooling oil 340 detected by the cooling oil temperature detection section 350, and attaches it to the rotor 310 based on these. Estimate the temperature of the permanent magnet (magnet temperature). In this embodiment, the estimated magnet temperature (hereinafter also referred to as an estimated magnet temperature value) is transmitted to the current command generation unit 140, for example. When the estimated magnet temperature is higher than a predetermined temperature, the current command generation unit 140 adjusts the torque command or current command to suppress the mechanical output (torque x rotation speed) of the motor 300 in order to prevent the temperature of the magnet from rising. The current command values (Id*, Iq*) are sent to the current control unit 110.

Next, the operation of the magnet temperature estimator 400 in this embodiment will be explained with reference to FIG. 2.

FIG. 2 shows the configuration of the magnet temperature estimator 400 in this embodiment. The magnet temperature estimator 400 includes a coil temperature function 410, a cooling oil temperature function 420, a first multiplier 430, a second multiplier 440, and an adder 450.

The coil temperature function 410 inputs the coil temperature detected by the coil temperature detection section 360 (detected value of the coil temperature detection section 360), and outputs a first coefficient.

The cooling oil temperature function 420 inputs the cooling oil temperature detected by the cooling oil temperature detection section 350 (detected value of the cooling oil temperature detection section 350), and outputs a second coefficient.

A first multiplier 430 multiplies the first coefficient by the coil temperature. A second multiplier 440 multiplies the second coefficient by the cooling oil temperature. The adder 450 adds the output (multiplication value) of the first multiplier 430 and the output (multiplication value) of the second multiplier 440 and outputs the result as an estimated magnet temperature.

Next, the coil temperature function 410 and the cooling oil temperature function 420 will be explained with reference to FIGS. 3 to 6. As in this embodiment, the magnet temperature of the permanent magnet attached to the rotor 310 is determined based on the temperature of the coil 380 wound around the stator 330 and the temperature of the cooling oil 340 as shown in FIG. Determined from the thermal circuit. The thermal circuit shown in FIG. 3 includes a coil, a magnet, and cooling oil connected through thermal resistances (Roc, Rom, and Rcm). When determining the magnet temperature using the thermal circuit shown in FIG. 3, it can be determined if the three thermal resistances, the coil temperature, and the cooling oil temperature are known, but it is difficult to accurately determine the thermal resistance. Therefore, as in Patent Document 1, for example, it is determined by changing the estimation formula or changing the thermal resistance depending on the operating state (rotation speed/torque) of the motor 300. However, how to change the three thermal resistances according to the operating state of the motor 300 is often determined experimentally, which requires experimental work and thermal resistance identification work, which increases development costs and increases the cost of magnets. This led to the complexity of the temperature estimator. This embodiment prevents such an increase in development cost and complication of the magnet temperature estimator.

FIG. 4 shows the operation of the thermal circuit (same shape as FIG. 3) in the motor 300 according to the present embodiment when the amount of heat generated by the coil 380 is large and the temperature of the cooling oil 340 is low. When the amount of heat generated by the coil 380, which is the heat source, is large and the temperature of the cooling oil 340 is low, the temperature difference between the coil 380 and the cooling oil 340 is large, so the heat generated by the coil 380 is easily transmitted to the cooling oil 340, and the cooling is carried out from the coil 380. The heat flow to oil 340 increases. Since the heat flow to the cooling oil 340 is large, the heat flow from the coil 380 to the magnet is small.

On the other hand, as shown in FIG. 5, when the amount of heat generated by the coil 380, which is the heat source, is large and the temperature of the cooling oil 340 is high, the temperature difference between the coil 380 and the cooling oil 340 is small, so the heat generated by the coil 380 is absorbed by the cooling oil. 340, and the flow rate of heat from the coil 380 to the cooling oil 340 becomes small. As a result, the heat flow from the coil 380 to the magnet increases.

As described in the operation of FIGS. 4 and 5, the heat flow rate transferred to the magnet changes depending on the temperature of the coil 380 and the temperature of the cooling oil 340. That is, as shown in FIG. 6, the thermal resistance Rom between the cooling oil 340 and the magnet changes with the temperature of the cooling oil 340 (depending on the temperature of the cooling oil 340), and the thermal resistance Rom between the coil 380 and the magnet changes with the temperature of the cooling oil 340 (depending on the temperature of the cooling oil 340). If Rcm is set to vary with the temperature of the coil 380 (depending on the temperature of the coil 380), the magnet temperature can be estimated without considering the thermal resistance Roc between the coil 380 and the cooling oil 340. Since the configuration can be simplified, complexity can be prevented. The coil temperature function 410 and cooling oil temperature function 420 in FIG. 2 are configured to reflect the operations in FIGS. 4 and 5. The coil temperature function 410 in this embodiment is expressed, for example, as shown in the following <Equation 1>, and the cooling oil temperature function 420 is expressed, for example, as shown in the following <Equation 2>. By using these coil temperature function 410 and cooling oil temperature function 420, the magnet temperature can be expressed, for example, as shown in the following <Equation 3>. As a result, the first coefficient, which is the output of the coil temperature function 410, changes depending on the temperature of the coil 380, which is the detected value of the coil temperature detection section 360, and the second coefficient, which is the output of the cooling oil temperature function 420. changes depending on the temperature of the cooling oil 340, which is the detected value of the cooling oil temperature detection unit 350, and the magnet temperature (estimated magnet temperature) is calculated using those coefficients that reflect the operations shown in FIGS. 4 and 5. Since it can be estimated, the magnet temperature can be estimated with a simple configuration without complication.
<Number 1>
F1 = A x Tc + B
F1: Coil temperature function, A, B: Constant, Tc: Coil temperature <Math. 2>
F2 = C×To + D
F2: Cooling oil temperature function, C, D: Constant, To: Cooling oil temperature <Math. 3>
Tm = F1 x Tc + F2 x To
Tm: magnet temperature

To determine the coil temperature function 410 and the cooling oil temperature function 420, the coil temperature, magnet temperature, and cooling oil temperature are measured in advance. An estimated magnet temperature value is calculated from the measured coil temperature and cooling oil temperature using <Equation 3>, and the coil temperature function 410 and cooling oil temperature function 420 are All you have to do is decide. At this time, the coil temperature function 410 and the cooling oil temperature function 420 can be determined by using an optimization algorithm such as the least squares method. By performing these series of operations under various operating conditions (rotation speed, torque, ambient temperature), the coil temperature function 410 and the cooling oil temperature function 420 can be determined.

In this embodiment, the coil temperature detection section 360 that detects the temperature of the coil 380 wound around the stator 330 is used, but the temperature of the coil 380 is obtained using (detecting) the temperature of the stator 330. It's okay. Further, the temperature of the cooling oil 340 is obtained by the cooling oil temperature detection section 350, but the temperature of the cooling oil 340 is detected using (detecting) the temperature of the case of the cooling oil 340 or the housing (not shown) of the motor 300. You can also get the temperature.

In addition, the input to the coil temperature function 410 is the temperature of the coil 380, and the input to the cooling oil temperature function 420 is the temperature of the cooling oil 340, but in both cases, the temperature difference between the coil 380 and the cooling oil 340 as shown in FIG. 7 is input. It may be in the form of

In the magnet temperature estimator 400A shown in FIG. 7, the coil temperature function 410A and the cooling oil temperature function 420A input the temperature difference between the coil 380 and the cooling oil 340, and output a first coefficient and a second coefficient, respectively. The first multiplier 430A multiplies the first coefficient by the coil temperature. The second multiplier 440A multiplies the second coefficient by the cooling oil temperature. The adder 450A adds the output (multiplication value) of the first multiplier 430A and the output (multiplication value) of the second multiplier 440A, and outputs the result as an estimated magnet temperature.

In addition, in this embodiment, the above <Equation 1> is used for the coil temperature function 410, and the above <Equation 2> is used for the cooling oil temperature function 420, but a function expressed by a quadratic expression or an exponential function may also be used. Of course.

As explained above, the motor control device 800 of this embodiment includes a motor 300 having a rotor 310 to which a permanent magnet is attached, a stator 330 around which a coil 380 is wound, and a temperature control device for controlling the temperature of the coil 380. A coil temperature detection section 360 detects the temperature of the cooling oil 340 that cools the motor 300, a cooling oil temperature detection section 350 detects the temperature of the cooling oil 340 that cools the motor 300, and the temperature of the coil 380 which is the detected value of the coil temperature detection section 360 and the cooling oil. A magnet temperature estimator 400 that estimates the magnet temperature of the permanent magnet of the motor 300 using the temperature of the cooling oil 340 that is the detected value of the temperature detection section 350, and the magnet temperature estimator 400 includes: Estimating the magnet temperature using a first coefficient that changes depending on the value detected by the coil temperature detection unit 360 and a second coefficient that changes depending on the value detected by the cooling oil temperature detection unit 350. do.

Further, the magnet temperature estimator 400 of this embodiment has a first coefficient that changes depending on the temperature of a coil 380 wound around the stator 330 of the motor 300, and a coefficient of the cooling oil 340 that cools the motor 300. The magnet temperature of the permanent magnet attached to the rotor 310 of the motor 300 is estimated using the second coefficient that changes depending on the temperature.

According to this embodiment, the coil temperature function 410 and the cooling oil temperature function 420 (i.e., the first coefficient and the second coefficient) are set so that the thermal resistances Rom and Rcm change according to the coil temperature and the cooling oil temperature. By providing this, the magnet temperature can be estimated without using the thermal resistance Roc, which reduces development costs and prevents the magnet temperature estimator from becoming complicated. It is possible to estimate the magnet temperature with high accuracy.

Further, as in the example shown in FIG. 7, the first coefficient and the second coefficient are the difference between the detection value of the coil temperature detection unit 360 and the detection value of the cooling oil temperature detection unit 380 and the cooling oil 340), it becomes possible to more precisely reflect the operation shown in FIGS. 4 and 5, that is, the operation that reflects the temperature difference between the coil 380 and the cooling oil 340. It is possible to estimate the magnet temperature with higher accuracy.

[Second embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIG. 6 and FIGS. 8 to 10.

FIG. 8 shows the configuration of a motor control device 900 in a second embodiment according to the present invention.

The motor control device 900 includes a motor 300, a motor drive device 100, a rotation speed calculating section 150, and a magnet temperature estimator 500. In the motor control device 900 in this embodiment, the inputs of the magnet temperature estimator 500 are the temperature of the coil 380 detected by the coil temperature detection section 360, the temperature of the cooling oil 340 detected by the cooling oil temperature detection section 350, and the magnet temperature. This differs from the motor control device 800 of the first embodiment in that it is an estimated value and that it includes a rotation speed calculating section 150. The other configurations are the same as those in the first embodiment, so detailed description will be omitted.

The rotation speed calculation unit 150 converts the rotation angle θ of the rotor 310 detected by the resolver 320 into the rotation speed (rpm) of the motor 300 and sends it to the magnet temperature estimator 500.

Further, the torque command transmitted from the host control device (not shown) is not only transmitted to the current command generation unit 140 similarly to the first embodiment, but also inputted to the magnet temperature estimator 500.

FIG. 9 shows the configuration of a magnet temperature estimator 500 in this embodiment. The magnet temperature estimator 500 includes a coil temperature function 510, a cooling oil temperature function 520, a magnet temperature function 530, a loss map 540, a first multiplier 550, a second multiplier 560, and a third multiplier. It includes a multiplier 570, a loss/temperature conversion coefficient 580, and an adder 590.

The functions of the coil temperature function 510, the cooling oil temperature function 520, the first multiplier 550, and the second multiplier 560 are the same as the coil temperature function 410 and the cooling oil temperature function of FIG. 2 in the first embodiment. 420, the first multiplier 430, and the second multiplier 440, detailed description thereof will be omitted here.

In the first embodiment, as shown in FIG. 6, by changing the thermal resistances Rom and Rcm according to the temperature of the cooling oil 340 and the temperature of the coil 380, the magnet temperature can be estimated with high accuracy even though the configuration is simple. Indicated. However, since the magnet (or rotor 310) actually has a heat capacity, the temperature of the coil 380 and the temperature of the cooling oil 340 are not immediately reflected on the magnet. Therefore, in the second embodiment, the heat capacity is taken into consideration by estimating the magnet temperature using the previous value of the estimated magnet temperature (magnet temperature estimation value). As shown in the first embodiment, the heat flow rate transferred to the magnet changes depending on the temperature of the coil 380 and the temperature of the cooling oil 340, so the heat capacity of the magnet (or rotor 310) also changes equivalently. It is regarded. A magnet temperature function 530 is provided as a function of this function.

The magnet temperature function 530 receives the estimated magnet temperature (previous value) output by the magnet temperature estimator 500 and outputs a third coefficient. The third coefficient determined by the estimated magnet temperature (previous value) is input to the third multiplier 570, and the result of multiplication by the estimated magnet temperature (previous value) is input to the adder 590.

Note that the magnet temperature function 530 (that is, the third coefficient) can be determined in the same manner as the coil temperature function 410 and cooling oil temperature function 420 in the first embodiment.

In addition, iron losses such as eddy current loss and hysteresis loss occur in the magnet due to harmonic components of the magnetic flux generated by the current. Therefore, the magnet itself also becomes a heat source. In the second embodiment, a loss map 540 determined by the rotation speed transmitted from the rotation speed calculation unit 150 and the torque transmitted from a host control device (not shown) is provided to obtain the heat generation amount of the magnet. The amount of heat generated by the magnet obtained from the loss map 540 is multiplied by a loss-temperature conversion coefficient 580, converted to a magnet temperature, and input to the adder 590.

The adder 590 outputs the output (multiplication value) of the first multiplier 550, the output (multiplication value) of the second multiplier 560, the output (multiplication value) of the third multiplier 570, and the conversion coefficient 580. The sum of the outputs is output as the estimated magnet temperature.

This embodiment, like the first embodiment, expresses that the heat flow rate changes depending on the temperature difference between the coil 380 and the cooling oil 340. Therefore, as shown in FIG. 10, the input to the coil temperature function 510A and the cooling oil temperature function 520A may be the temperature difference between the coil 380 and the cooling oil 340. Further, the input to the magnet temperature function 530A may be at least one of the difference between the temperature of the coil 380 and the estimated magnet temperature (previous value) or the difference between the temperature of the cooling oil 340 and the estimated magnet temperature (previous value).

In the magnet temperature estimator 500A shown in FIG. 10, the coil temperature function 510A and the cooling oil temperature function 520A input the temperature difference between the coil 380 and the cooling oil 340, and output a first coefficient and a second coefficient, respectively. The magnet temperature function 530A inputs at least one of the difference between the temperature of the coil 380 and the estimated magnet temperature (previous value) or the difference between the temperature of the cooling oil 340 and the estimated magnet temperature (previous value), and outputs a third coefficient. do. The first multiplier 550A multiplies the first coefficient by the coil temperature. The second multiplier 560A multiplies the second coefficient by the cooling oil temperature. The third multiplier 570A multiplies the third coefficient by the estimated magnet temperature (previous value). The loss map 540A inputs the rotation speed and torque to obtain the heat generation amount of the magnet, and the conversion coefficient 580A converts the obtained heat generation amount of the magnet into magnet temperature. The adder 590A outputs the output (multiplication value) of the first multiplier 550A, the output (multiplication value) of the second multiplier 560A, the output (multiplication value) of the third multiplier 570A, and the output of the conversion coefficient 580A. Add and output as estimated magnet temperature.

Note that the loss and temperature conversion coefficients 580 and 580A do not need to be fixed values. For example, it may be a value that changes depending on the rotation speed.

As explained above, in addition to the first embodiment, the motor control device 900 (the magnet temperature estimator 500) of the second embodiment has the advantage that the magnet temperature estimation value output by the magnet temperature estimator 500 is The magnet temperature of the permanent magnet of the motor 300 is estimated using the third coefficient determined by the previous value and the loss of the motor 300 determined by the rotation speed and torque.

According to the present embodiment, in addition to the first embodiment, a magnet temperature function 530 (that is, a third coefficient) that takes into account the heat capacity of the magnet (or stator) and a loss map 540 that takes into account the heat generation of the magnet are provided. By providing this, it is possible to estimate the magnet temperature with higher accuracy.

Further, as in the example shown in FIG. 10, the first coefficient and the second coefficient are the difference between the detection value of the coil temperature detection unit 360 and the detection value of the cooling oil temperature detection unit 350 (that is, the difference between the detection value of the coil temperature detection unit 360 and the detection value of the cooling oil temperature detection unit 350 380 and the cooling oil 340), and the third coefficient is determined from the difference between the detected value of the coil temperature detecting section 360 and the previous value of the magnet temperature estimate, or the detected value of the cooling oil temperature detecting section 350. 4 and 5, that is, the temperature difference between the coil 380 and the cooling oil 340, as in the first embodiment. Since the operation can be reflected more precisely, the magnet temperature of the motor 300 can be estimated with higher accuracy.

Note that the present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-described embodiments have been described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

Further, each of the above-mentioned configurations, functions, processing units, processing means, etc. may be partially or entirely realized in hardware by designing, for example, an integrated circuit. Furthermore, each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function. Information such as programs, tables, files, etc. that implement each function can be stored in a memory, a storage device such as a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

Further, the control lines and information lines are shown to be necessary for explanation purposes, and not all control lines and information lines are necessarily shown in the product. In reality, almost all components may be considered to be interconnected.

DESCRIPTION OF SYMBOLS 100... Motor drive device, 110... Current control part, 120... Current detection part, 130... Inverter, 140... Current command generation part, 150... Rotation speed calculation part (2nd embodiment), 200... Battery, 300... Motor , 310... Rotor, 320... Resolver (rotation angle sensor), 330... Stator, 340... Cooling oil, 350... Cooling oil temperature detection section, 360... Coil temperature detection section, 370... Cooling oil pump, 380... Coil, 400... Magnet temperature estimator (first embodiment), 410... Coil temperature function, 420... Cooling oil temperature function, 430... First multiplier, 440... Second multiplier, 450... Adder, 500... Magnet temperature estimator (second embodiment), 510... Coil temperature function, 520... Cooling oil temperature function, 530... Magnet temperature function, 540... Loss map, 550... First multiplier, 560... Second multiplication 570...Third multiplier, 580...Conversion coefficient, 590...Adder, 800...Motor control device (first embodiment), 900...Motor control device (second embodiment)

Claims (8)

A motor having a rotor having a permanent magnet attached thereto and a stator having a coil wound thereon;
a coil temperature detection section that detects the temperature of the coil;
a cooling oil temperature detection unit that detects the temperature of cooling oil that cools the motor;
A motor control device comprising: a magnet temperature estimator that estimates a magnet temperature of the permanent magnet of the motor using a detection value of the coil temperature detection unit and a detection value of the cooling oil temperature detection unit,
The magnet temperature estimator uses a first coefficient that changes according to the detection value of the coil temperature detection section and a second coefficient that changes according to the detection value of the cooling oil temperature detection section, estimating the magnet temperature ;
A motor control device characterized in that the first coefficient and the second coefficient are determined from a difference between a detection value of the coil temperature detection section and a detection value of the cooling oil temperature detection section. The motor control device according to claim 1,
The motor control device is characterized in that the magnet temperature estimator estimates the magnet temperature using a third coefficient determined by a previous value of the magnet temperature estimation value output by the magnet temperature estimator. The motor control device according to claim 1,
A motor control device characterized in that the magnet temperature estimator estimates the magnet temperature using loss of the motor. The motor control device according to claim 2 ,
The third coefficient is one of the differences between the detection value of the coil temperature detection section and the previous value of the magnet temperature estimation value, or the difference between the detection value of the cooling oil temperature detection section and the previous value of the magnet temperature estimation value. A motor control device characterized in that the determination is made from at least one side. The motor control device according to claim 1,
The magnet temperature estimator adds the multiplication value of the first coefficient and the detection value of the coil temperature detection section and the multiplication value of the second coefficient and the detection value of the cooling oil temperature detection section to estimate the magnet temperature. A motor control device characterized by estimating temperature. The motor control device according to claim 1,
A motor control device characterized in that when the estimated magnet temperature value outputted by the magnet temperature estimator is higher than a predetermined temperature, the motor is controlled to suppress the mechanical output of the motor. A magnet temperature estimator for estimating the magnet temperature of a permanent magnet attached to a rotor of a motor,
Using a first coefficient that changes depending on the temperature of a coil wound around the stator of the motor, and a second coefficient that changes depending on the temperature of cooling oil that cools the motor, the magnet Estimate the temperature,
The magnet temperature estimator , wherein the first coefficient and the second coefficient are determined from a difference between the temperature of the coil and the temperature of the cooling oil . A magnet temperature estimation method for estimating the magnet temperature of a permanent magnet attached to a motor rotor, the method comprising:
Using a first coefficient that changes depending on the temperature of a coil wound around the stator of the motor, and a second coefficient that changes depending on the temperature of cooling oil that cools the motor, the magnet Estimate the temperature,
The first coefficient and the second coefficient are obtained from a difference between the temperature of the coil and the temperature of the cooling oil .

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