Parameter setting device for setting model parameters of a motor

Abstract

The model of the motor includes a model of the stator coil and a model of the temperature detector for detecting the temperature of the coil. Parameters such as heat capacity are included in the model of the motor. The parameter setting section has a parameter calculation section that calculates parameters so that the temperature change of the model of the temperature detector corresponds to the actual temperature change. The parameter calculation section includes an evaluation section that evaluates the temperature of the model of the temperature detector calculated using the parameters set temporarily. The evaluation section evaluates the temperature of the model of the temperature detector without evaluating variables other than the temperature of the model of the temperature detector.

Description

TECHNICAL FIELD

[0001] The present application relates to a parameter setting device that sets model parameters of an electric motor. BACKGROUND

[0002] Generally, it is known that an electric motor temperature rises by driving. If the electric motor temperature becomes excessively high, there is a case where the electric motor cannot accurately operate or a constituent component is damaged.

[0003] The actual temperature at the time of driving the electric motor can be detected by a temperature detector installed to the constituent component. Alternatively, in the related art, an analog device that estimates a machine temperature is known. An operator generates a CAD (Computer Aided Design) model of a machine, and sets material properties or thermal movement properties and the like to the constituent components. Furthermore, by calculation of a finite element method or the like that calculates each minute region of the device, the temperature of each constituent component can be estimated (for example, refer to Japanese Patent Application Laid-Open No. 2020-12654).

[0004] However, the material properties and the thermal movement properties of the constituent components depend on the surface properties and the like of the constituent components. Therefore, there is a problem that the operator cannot easily input correct values. In addition, there is a problem that it is difficult to predict the temperature with sufficient accuracy. In addition, in the finite element method, in order to improve the accuracy of the estimated temperature, the region in which the constituent component is divided can be reduced. However, if the region in which the constituent component is divided is reduced, the amount of calculation for calculating the thermal movement increases.

[0005] In order to estimate the machine temperature, a method of using a thermal model that takes into account the heat capacity of the constituent components and the heat transfer between the constituent components is known (for example, Japanese Patent Application Laid-Open No. 2014-36475, Japanese Patent Application Laid-Open No. 2016-55657, and Japanese Patent Application Laid-Open No. 2018-527019). In the thermal model, a heat transfer coefficient or a thermal resistance is set between each of the constituent components, and the heat transfer between the constituent components is calculated, whereby the temperature of each of the constituent components can be calculated.

[0006] In the electric motor, a device that estimates the temperature at the time of driving the electric motor using a thermal model including a stator core, a coil, and a rotor core and the like is also known (for example, Japanese Patent Application Laid-Open No. 2008-109816).

[0007] PRIOR ART DOCUMENTS

[0008] PATENT DOCUMENTS

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-12654

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-36475

[0011] Patent Literature 3: Japanese Patent Application Laid-Open (JP A) No. 2016-55657

[0012] Patent Literature 4: Japanese Patent Application Laid-Open (JP A) No. 2018-527019

[0013] Patent Literature 5: Japanese Patent Application Laid-Open (JP A) No. 2008-109816 SUMMARY

[0014] PROBLEMS TO BE SOLVED BY THE INVENTION

[0015] When the motor is driven, heat is generated in the stator core, the coil fixed to the stator core, the bearing, and the like. Among them, there is a case where the temperature of the coil composed of the winding wound around the stator core is the highest. The temperature detector for detecting the temperature of the motor can be configured to detect the temperature of the coil, for example.

[0016] If the temperature output by the temperature detector exceeds the temperature determination value, the control device of the motor can determine that the motor has generated overheating. At this time, it is not possible to maintain the operating state of the motor. The control device implements control to stop the motor or reduce the motor speed.

[0017] In a machine including a motor, it is preferable to implement simulation of driving the machine in a desired operating mode, so that it is possible to estimate whether the operating mode is allowed. The temperature change of the motor can be estimated according to the operating mode, and thus the operating state of the motor is determined. Alternatively, the operator can change the operating mode of the machine when the temperature of the motor is overheated. The operator can generate the operating mode of the machine so that overheating does not occur in the motor. In this way, it is preferable that the operator can determine whether the motor can operate normally even if the machine is not actually driven.

[0018] MEANS FOR SOLVING THE PROBLEMS

[0019] The parameter setting device of this disclosure sets parameters included in a model of an electric motor, which are used to estimate the temperature of a temperature detector that detects the temperature of a component constituting the electric motor. The parameter setting device includes a status acquisition unit that acquires the operating command of the electric motor generated by actually driving the motor and the temperature output from the temperature detector. The parameter setting device also includes a parameter calculation unit that calculates parameters such that the temperature change of the temperature detector model calculated from the electric motor model corresponds to the actual temperature change. The electric motor model includes a rotor model, a stator core model, a coil model, and a temperature detector model as models of the components of the electric motor. The parameters include the heat capacity set for the models of the components and coefficients related to heat transfer between the models of the components. The parameter calculation unit includes a loss calculation unit that calculates the heat generated by the primary copper loss of the coil and the heat generated by the iron loss of the stator core based on the operating command. The parameter calculation unit also includes a temperature calculation unit that calculates the temperature of the temperature detector model using the electric motor model based on the heat generated by the coil and the heat generated by the stator core. The parameter calculation unit includes an evaluation unit that evaluates the temperature of the temperature detector model by comparing the temperature of the model with the temperature of the temperature detector obtained by the state acquisition unit. The parameter calculation unit also includes a parameter modification unit that modifies the parameter values ​​based on the evaluation results from the evaluation unit. The evaluation unit evaluates the temperature of the temperature detector model but not variables other than the temperature of the model.

[0020] Invention Effects

[0021] According to the present disclosure, a parameter setting device can be provided for setting parameters of an electric motor model, which are used to estimate the temperature of the components of the electric motor. Attached Figure Description

[0022] Figure 1 This is a block diagram of the machine and temperature estimation device in the implementation method.

[0023] Figure 2 This is a schematic cross-sectional view of the first electric motor in the embodiment.

[0024] Figure 3 This is a model of the first electric motor in the implementation method.

[0025] Figure 4 This is a graph illustrating the first operating mode of the motor when the parameters in the motor model are set.

[0026] Figure 5 This is a graph illustrating the second operating mode of the motor when the parameters in the motor model are set.

[0027] Figure 6is a model of the second electric motor in the embodiment.

[0028] Figure 7 is a first graph that illustrates a current flowing in the second electric motor.

[0029] Figure 8 is a second graph that illustrates a current flowing in the second electric motor.

[0030] Figure 9 is a graph of a simulation result using a parameter set by the parameter setting section.

[0031] Figure 10 is a graph that shows a relationship between a rotor temperature and a coefficient for correcting iron loss.

[0032] Figure 11 is a graph that shows a relationship between a coil temperature and a primary resistance.

[0033] Figure 12 is a graph that shows a relationship between a temperature difference between constituent parts and a constant for correcting a coefficient related to heat transfer.

[0034] Figure 13 is a graph that shows a relationship between a temperature of a constituent part and a constant for correcting a heat capacity. DETAILED DESCRIPTION

[0035] REFERENCE Figures 1 to 13 A parameter setting device that sets parameters of a model of an electric motor, which are used in a temperature estimation device, is described in the embodiment. When the electric motor is driven, the temperature of a constituent part that constitutes the electric motor rises. The temperature estimation device of the present embodiment estimates the temperature of an output of a temperature detector mounted to one of the constituent parts included in the electric motor. In the present embodiment, an example of estimating the temperature of an output of a temperature detector that detects the temperature of one of the constituent parts of the electric motor, i.e., a stator coil, is described. At this time, the temperature detector is mounted to the coil fixed to the stator core.

[0036] The temperature estimation device estimates the temperature of the temperature detector using a model of the electric motor. The model of the electric motor of the present embodiment is a thermal model that represents heat movement of the constituent parts to each other. The parameter setting device of the present embodiment sets parameters such as a heat capacity of a constituent part and a coefficient related to heat transfer between the constituent parts in the model of the electric motor. As the coefficient related to heat transfer, a heat transfer coefficient or a coefficient obtained by multiplying the heat transfer coefficient by a contact area of the constituent parts to each other, etc. can be adopted.

[0037] Figure 1is a block diagram of a machine and a temperature estimation device that estimates a temperature output from a temperature detector of a motor according to the present embodiment. The machine 1 according to the present embodiment has a motor 10 that drives constituent components of the machine 1 and a control device 41 that controls the motor 10. The control device 41 according to the present embodiment is constituted by an arithmetic processing device (computer). The control device 41 includes a CPU (Central Processing Unit) as a processor. The control device 41 has a RAM (Random Access Memory) and a ROM (Read Only Memory) and the like connected to the CPU via a bus.

[0038] The machine 1 according to the present embodiment is a numerical control machine. The machine 1 is driven in accordance with an instruction sentence described in an action program 45. The action program 45 is generated in advance by an operator. The control device 41 includes a storage section 42 that stores the action program 45 and an action control section 43 that generates an action instruction of the motor 10 in accordance with the action program 45. The machine 1 includes a drive device 44 that includes a circuit that supplies power to the motor 10 in accordance with the action instruction generated by the action control section 43. The motor 10 is driven by being supplied with power by the drive device 44.

[0039] The storage section 42 can be constituted by a volatile memory, a non-volatile memory, or a hard disk or the like that is a non-transitory storage medium capable of storing information. The action control section 43 corresponds to a processor that drives in accordance with the action program 45. The processor reads in the action program 45 and implements control determined in the action program 45, whereby the action control section 43 functions.

[0040] As such a machine 1, any machine having the motor 10 can be adopted. For example, as the machine 1, a machine tool that processes a workpiece can be exemplified. As the motor 10, a spindle motor that rotates a tool or a workpiece or a feed shaft motor that moves a table or a spindle head along a predetermined coordinate axis can be exemplified.

[0041] Figure 2 is a cross-sectional view of the first motor according to the present embodiment. Referring to Figure 1 and Figure 2 , the first motor 10 is a synchronous motor in which the rotor 11 has a magnet 18. The motor 10 has the rotor 11 and a stator 12. The stator 12 includes a stator core 20 formed of a material having magnetism and a coil 16 fixed to the stator core 20. The stator core 20 is formed of, for example, a plurality of magnetic steel sheets stacked in the axial direction. The coil 16 includes, for example, a winding wound around the stator core 20 and a resin portion that fixes the winding.

[0042] The rotor 11 is fixed to a shaft 13 formed in a bar shape. The rotor 11 includes a rotor core 17 fixed to an outer peripheral surface of the shaft 13 and formed of a material having magnetism, and a plurality of magnets 18 fixed to the rotor core 17. The magnets 18 of the present embodiment are permanent magnets.

[0043] The shaft 13 is coupled to other components in order to transmit a rotational force. The shaft 13 rotates around a rotational axis RA. The axial direction in the present embodiment indicates a direction in which the rotational axis RA of the shaft 13 extends. In the present embodiment, the side of the motor 10 to which the shaft 13 is coupled to other components is referred to as a front side. In addition, the side opposite to the front side is referred to as a rear side. In the present embodiment, the front side is a side on which the temperature detector 31 and the rotational position detector 32 are arranged. In addition, the rear side is a side on which the stator 12 is arranged. Figure 2 In the example shown in the drawing, an arrow 81 indicates the front side of the motor 10.

[0044] The motor 10 includes a housing 21 on the front side and a housing 22 on the rear side as a frame. The rotor 11 is arranged inside the frame. The stator core 20 of the stator 12 is supported to the housings 21 and 22. The housing 21 supports the bearing 14. The bearing support member 26 that supports the bearing 15 is fixed to the housing 22. The housings 21 and 22 support the shaft 13 to be rotatable via the bearings 14 and 15. The rear cover 23 that closes the inside space of the housing 22 is fixed to the rear end portion of the housing 22. In this way, as the components of the motor 10, for example, the rotor 11, the rotor core 17, the magnets 18, the stator 12, the stator core 20, the coil 16, the housings 21 and 22, the shaft 13, the rear cover 23, the bearing support member 26, the bearings 14 and 15, the temperature detector 31, and the rotational position detector 32 can be cited. As the components of the motor 10, it is not limited to this way, but any part constituting the motor 10 can be adopted. For example, a housing that covers the stator can be adopted.

[0045] The rotational position detector 32 for detecting the rotational position or the rotational speed of the shaft 13 is arranged at the rear end portion of the shaft 13. The rotational position detector 32 of the present embodiment is constituted by an encoder. The temperature detector 31 that detects the temperature of the coil 16 is fixed to the coil 16 of the stator 12. The temperature detector 31 of the present embodiment is constituted by a thermistor. The outputs of the temperature detector 31 and the rotational position detector 32 are input to the control device 41.

[0046] When the temperature detected by the temperature detector 31 is higher than a predetermined temperature determination value, the control device 41 can determine that the motor 10 generates an overheat. At this time, the control device 41 can reduce the current value supplied to the motor 10, or stop the motor 10. In addition, the control device 41 can implement feedback control based on the output of the rotational position detector 32. For example, position feedback control that controls the rotational position of the shaft 13 of the motor 10 or speed feedback control that controls the rotational speed of the shaft 13 can be implemented.

[0047] The temperature estimation device 2 of this embodiment estimates the temperature output by the temperature detector 31 disposed in the coil 16 of the stator 12. In particular, in this embodiment, the temperature estimation device 2 estimates the temperature of the temperature detector 31. In addition, the temperature estimation device 2 estimates the change in the temperature of the temperature detector 31 over time.

[0048] The temperature estimation device 2 is constituted by an arithmetic processing device (computer) including a CPU as a processor. The temperature estimation device 2 includes a storage section 51 that stores information related to the temperature estimation of the motor 10. The storage section 51 can be constituted by a volatile memory, a non-volatile memory, or a non-transitory storage medium such as a hard disk that can store information. The temperature estimation device 2 includes a display section 52 that displays information related to the temperature of the motor 10. The display section 52 can be constituted by any display panel such as a liquid crystal display panel.

[0049] The temperature estimation device 2 includes an estimation section 53 that estimates the temperature of the temperature detector 31. The estimation section 53 performs a calculation according to a model (thermal model) of the motor, and thereby estimates the temperature of the temperature detector 31. The estimation section 53 includes a loss calculation section 54 that calculates the amount of heat generated by the primary copper loss of the coil 16 and the amount of heat generated by the iron loss of the stator core 20 according to the operation command of the motor 10. The estimation section 53 includes a temperature calculation section 55 that calculates the temperature of the temperature detector 31 using the model of the motor. The temperature calculation section 55 calculates the temperature of the temperature detector 31 according to the amounts of heat generated by the primary copper loss and the iron loss, the heat capacities of the respective constituent parts of the model of the motor 10, and the coefficients related to the heat transfer between the constituent parts of the model of the motor 10.

[0050] The temperature estimation device 2 of this embodiment has the function of a parameter setting device that sets parameters included in the model of the motor. The parameter setting section 61 of the temperature estimation device 2 functions as the parameter setting device. The parameter setting section 61 sets parameters including the heat capacities of the constituent parts of the motor 10 and the coefficients related to the heat transfer between the constituent parts.

[0051] The parameter setting section 61 includes a state acquisition section 62 that acquires the state of the motor 10 when the motor 10 is actually driven. The state acquisition section 62 acquires the operation command of the motor 10 generated when the motor 10 is actually driven, the rotational speed output from the rotational position detector 32, and the temperature output from the temperature detector 31. The operation command of the motor 10 is generated by the operation control section 43, and thus the operation command of the motor 10 can be acquired from the operation control section 43. In addition, the state acquisition section 62 can acquire the outside air temperature from the outside air temperature detector 33 that detects the temperature of the environment in which the machine 1 is disposed.

[0052] The parameter setting section 61 includes a parameter calculation section 63 that calculates parameters included in the model of the motor. The parameter calculation section 63 calculates the amount of heat generated in the coil 16 and the stator core 20 on the basis of the operation command generated by the operation control section 43 and the rotational speed detected by the rotational position detector 32. Further, the parameter calculation section 63 estimates the temperature of the model 31a of the temperature detector on the basis of the amount of heat generated in the coil 16 and the stator core 20. The parameter calculation section 63 calculates the model parameters of the motor on the basis of the temperature of the model 31a of the temperature detector and the temperature output from the temperature detector 31.

[0053] The parameter calculation section 63 of the present embodiment calculates parameters so that the temperature change of the model of the temperature detector calculated by the model of the motor corresponds to the actual temperature change. The parameter calculation section 63 can set the model parameters of the motor by machine learning. The parameter calculation section 63 estimates the temperature of the temperature detector by using the model of the motor by using the estimation section 53. The parameter calculation section 63 includes an evaluation section 66 that evaluates the temperature of the model 31a of the temperature detector by comparing the temperature of the model 31a of the temperature detector with the temperature of the temperature detector 31 acquired by the state acquisition section 62. The parameter calculation section 63 includes a parameter change section 67 that changes the parameter value on the basis of the evaluation result of the evaluation section 66.

[0054] The above-described estimation section 53, loss calculation section 54, and temperature calculation section 55 each correspond to a processor that is driven in accordance with a program. The parameter setting section 61, state acquisition section 62, and parameter calculation section 63 each correspond to a processor that is driven in accordance with a program. Further, the evaluation section 66 and parameter change section 67 included in the parameter calculation section 63 each correspond to a processor that is driven in accordance with a program. The processor implements control determined in a program, thereby functioning as each section.

[0055] Figure 3 The model of the motor 10a included in the model of the motor 10a in the present embodiment. The model of the motor 10a includes a model 11a of a rotor, a model 20a of a stator core, and a model 16a of a coil wound around the stator core. Further, the model of the motor 10a includes a model 31a of a temperature detector for detecting the temperature of the coil 16.

[0056] Further, with reference to Figure 2An air layer is interposed between the rotor 11 and the stator core 20. Also, an air layer is interposed between the rotor 11 and the coil 16. The model 10a of the motor of the present embodiment includes a model 35a of the air layer. Also, the model 10a of the motor includes a model 36a of the outside air as a model of the ambient air of the motor 10. In this way, in the model of the motor of the present embodiment, the air layer and the outside air are generated as models of the components of the motor.

[0057] The temperature detected by the temperature detector 31 is approximately equal to the temperature of the coil 16. However, the inventors have found that, under certain conditions, the temperature detected by the temperature detector 31 differs from the temperature of the coil 16 because the heat capacity of the temperature detector 31 is small. More strictly, the temperature detected by the temperature detector 31 is the temperature of the main body of the temperature detector 31. Therefore, in the present embodiment, a model 31a of the temperature detector is generated as one model of the components with respect to the temperature detector 31. Also, it is possible to calculate the temperature of the model 31a of the temperature detector by setting the temperature of the model 31a of the temperature detector to be the same as the temperature of the model of the component in which the temperature detector 31 is installed, without taking the heat capacity of the temperature detector 31 into account. In the example here, the temperature of the model 31a of the temperature detector can also be calculated by setting the temperature of the model 31a of the temperature detector to be the same as the temperature of the model 16a of the coil.

[0058] In the model 10a of the motor, a plurality of parameters including the heat capacity and the coefficients related to heat transfer are set. The heat capacity is set for each model of the components. For each of the model 16a of the coil, the model 20a of the stator core, the model 35a of the air layer, the model 11a of the rotor, and the model 31a of the temperature detector, the temperatures T1, T2, T3, T4, T5 as variables and the heat capacities C1, C2, C3, C4, C5 as constants are set. Also, for the model 36a of the outside air, the temperature T6 as a variable is set. r .

[0059] The heat of one component of the motor 10 is transferred to other components. In the model 10a of the motor, the movement of heat between the components is calculated. The coefficients related to heat transfer are set between each of the models of the components of the motor 10. In the example here, the coefficient obtained by multiplying the heat transfer coefficient by the contact area is determined.

[0060] A coefficient ha related to heat transfer is set between the model 20a of the stator core and the model 16a of the coil. A coefficient hc1 related to heat transfer is set between the model 35a of the air layer and the model 16a of the coil. A coefficient hc2 related to heat transfer is set between the model 35a of the air layer and the model 20a of the stator core. A coefficient hc3 related to heat transfer is set between the model 35a of the air layer and the model 11a of the rotor. A coefficient hd related to heat transfer is set between the model 16a of the coil and the model 31a of the temperature detector. Also, in order to simulate heat release from the stator core 20 to the outside air, a coefficient hb related to heat transfer is set between the model 20a of the stator core and the model 36a of the outside air.

[0061] In the model 10a of the motor of the present embodiment, as heat generated by the constituent parts, a primary copper loss P c1 generated in the coil 16 of the stator 12 is considered. The amount of heat generated by the primary copper loss is input to the model 16a of the coil. Also, an iron loss P i of the stator core 20 due to the magnetic force of the magnet 18 of the rotor 11 is considered. The amount of heat generated by the iron loss is input to the model 20a of the stator core.

[0062] Heat moves between the respective constituent parts such as the coil and the stator core depending on the magnitude of the coefficient related to heat transfer. Also, the temperature of each constituent part rises or falls depending on the difference between the input heat and the output heat. Figure 3 The temperature change rate of each constituent part of the model 10a of the motor shown can be expressed by the following equations (1) to (5). In each constituent part, the temperature change rate can be calculated by dividing the difference between the input heat and the output heat by the heat capacity.

[0063] [Mathematical Expression 1]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] T1: Temperature of coil C1: Heat capacity of coil

[0070] T2: Temperature of stator core C2: Heat capacity of stator core

[0071] T3: Temperature of air layer C3: Heat capacity of air layer

[0072] T4: temperature of rotor C4: heat capacity of rotor

[0073] T5: temperature of temperature detector C5: heat capacity of temperature detector

[0074] ha, hb, hc1, hc2, hc3, hd: coefficients related to heat transfer

[0075] P c1 : primary copper loss

[0076] P i : iron loss

[0077] The heat capacities C1, C2, C3, C4, C5 of the constituent parts are constants and can be determined in advance. The coefficients ha, hb, hc1, hc2, hc3, hd are coefficients obtained by multiplying the heat transfer coefficient by the contact area. The coefficients ha, hb, hc1, hc2, hc3, hd are constants and can be determined in advance. The loss calculation section 54 of the estimation section 53 calculates the primary copper loss P c1 and the iron loss P i in the stator core as described later. The temperature calculation section 55 of the estimation section 53 can calculate the temperature change amount in a small time dt according to the above-described equations (1) to (5).

[0078] Next, the calculation method of the primary copper loss P c1 and the iron loss P i included in the equations (1) and (2) will be described. The rotation speed of the motor 10 and the load rate (proportion with respect to the maximum load) of the motor 10 can be set in advance by an operator according to the work to be performed by the machine. The loss calculation section 54 of the estimation section 53 calculates the primary copper loss P c1 and the iron loss P i . The loss map for calculating the loss is shown in Table 1.

[0079] [Table 1]

[0080] Table 1 Loss Map

[0081]

[0082] In Table 1, the loss at the maximum output with respect to the rotation speed (rotational speed) of the motor 10, the loss at no load, and the current at the maximum output are shown. The loss P m at the maximum output is the loss when the load rate of the motor is 100%, and is a value determined by the rotation speed of the motor. The loss P n at no load is the loss when the load rate of the motor is zero, and depends on the rotation speed of the motor. The current I mis the current value at the time when the load factor is 100% at each rotational speed. The loss map shown in Table 1 can be made by actually driving the motor. The loss map can be stored in advance in the storage section 51 of the temperature estimation device 2, for example.

[0083] The loss calculation section 54 calculates the total loss P c1 containing the primary copper loss P i and the iron loss P t . The total loss P t can be calculated by the following equation (6) and equation (7).

[0084] [Equation 2]

[0085] P t = k2 · LF 2 + k1 · LF + P n … (6)

[0086] k1 = P m - P n - k2 … (7)

[0087] P t : total loss

[0088] P m : loss at the time of maximum output

[0089] P n : loss at the time of no load

[0090] LF: load factor of the motor

[0091] k1, k2: constants

[0092] The total loss P t can be calculated from the loss at the time of maximum output P m , the loss at the time of no load P n , and the load factor LF of the motor. Since the rotational speed and the load factor of the motor are determined, the loss at the time of maximum output P m and the loss at the time of no load P n are known from Table 1. The constants k1, k2 can be determined in advance by an operator. Next, the primary copper loss P c1 can be calculated by the following equation (8) and equation (9).

[0093] [Equation 3]

[0094] P c1 = r1 · I 2 … (8)

[0095] I = I m · LF … (9)

[0096] Pc1 : One copper loss

[0097] I: Current

[0098] rl: primary resistance

[0099] I m Current at maximum output

[0100] One copper loss P c1 This is equivalent to the Joule heat of the current flowing through coil 16. Furthermore, the current I flowing through coil 16 can be compared to the current I at maximum output. m Calculate by multiplying by the motor's load factor LF. Maximum output current I. m This can be obtained from Table 1. Here, the primary resistance r1 of coil 16 is measured beforehand. Next, the iron loss P... i The iron loss P can be calculated using the following formula (10). i This can be obtained from the total loss P t Subtract one copper loss P c1 To calculate.

[0101] [Mathematical Expression 4]

[0102] P i =P t -P c1 …(10)

[0103] P i Iron loss

[0104] The operator inputs the operating mode of the electric motor, including the rotational speed and load rate used to drive machine 1. The temperature calculation unit 55 of the estimation unit 53 can first set the temperatures T1 to T5 of each component to arbitrary temperatures. For example, the temperature calculation unit 55 sets the temperatures T1 to T5 of the components to the normal outside air temperature T. r The temperature of the outside air, T r The location where machine 1 is configured can be determined in advance.

[0105] The loss calculation unit 54 of the estimation unit 53 calculates the primary copper loss and iron loss based on the rotational speed and motor load rate in the operating mode. Next, the temperature calculation unit 55 calculates the change in temperature T5 of the temperature detector 31 over a small time interval dt by solving equations (1) to (5) above. In this way, the operator can determine the motor's operating mode and estimate the change in temperature of the temperature detector over time when the motor is operating in the operating mode. The operator can adjust the motor's operating mode, including the rotational speed and motor load rate, based on the temperature change of the temperature detector 31. That is, the operator can adjust the operating mode of the machine including the motor.

[0106] However, in the model 10a of the motor of the embodiment, it is only necessary to estimate the temperature of one of the plurality of components of the motor with high precision. The temperatures of the components other than the one component can deviate from the actual temperatures. That is, the temperatures of the components other than the one component are temperatures different from the actual temperatures, and can not correspond to the actual temperatures. In the example here, it is only necessary to estimate the temperature T5 of the model 31a of the temperature detector with high precision, and the temperature T1 of the model 16a of the coil, the temperature T2 of the model 20a of the stator core, the temperature T3 of the model 35a of the air layer, and the temperature T4 of the model 11a of the rotor can also greatly deviate from the actual temperatures.

[0107] Further, the heat capacities C1 to C5 set to the model 10a of the motor and the heat transfer-related coefficients ha, hb, hc1 to hc3, hd set between the components have inherent values depending on the materials, shapes, and arrangements of the components, and the like. However, in the model 10a of the motor of the embodiment, at least some of the plurality of heat capacities and the plurality of heat transfer-related coefficients are set to values deviating from the actual heat capacities or the actual heat transfer-related coefficients. In other words, at least some of the parameters are set to values different from the actual heat capacities or the actual heat transfer-related coefficients.

[0108] The respective parameters are set so that the change in the temperature T5 of the model 31a of the temperature detector corresponds to the actual change in the temperature. In the model 10a of the motor of the embodiment, by performing the calculation of the heat transfer between the models of the components, the change in the temperature of the temperature detector 31 corresponds to the actual change in the temperature. For example, the model parameters of the motor are set so that even if the temperatures of the coil, the stator core, and the like deviate from the actual temperatures, the temperature of the temperature detector indicates a value close to the actual temperature. Further, in the parameter setting device described later, the heat capacities and the heat transfer-related coefficients are set, and as a result, even if all of the heat capacities of the components and all of the heat transfer-related coefficients become the same as the actual heat capacities and the actual heat transfer-related coefficients, it is possible. Further, when the temperature of the component is estimated by the estimation unit, even if the temperature of all of the components is the same as the actual temperature of the component, it is possible.

[0109] In this way, the model of the motor in the embodiment is generated in order to estimate the temperature output by the temperature detector mounted to the stator coil that is one component of the motor. Next, a parameter setting device that sets parameters including heat transfer-related coefficients and heat capacities will be described.

[0110] Reference Signs List Figure 1The parameter setting section 61 of the present embodiment sets the heat capacity, the coefficient related to heat transfer, and the constants k1, k2 in the equations (6), (7) included in the model 10a of the motor. An operator actually drives the motor 10 according to a predetermined operation mode. The state acquisition section 62 acquires the load factor of the motor 10, the rotational speed of the motor 10, and the temperature output from the temperature detector 31 as the state of the motor 10. Also, the state acquisition section 62 acquires the temperature of the outside air from the outside air temperature detector 33.

[0111] Figure 4 A graph showing a first operation mode when the motor is driven in order to set the parameters included in the model of the motor of the present embodiment. Figure 4 An operation mode when there is no load. In this operation mode, no load is applied to the motor 10, and the rotational speed of the motor 10 is gradually increased. The load factor of the motor is temporarily increased at predetermined time intervals, whereby the rotational speed of the motor 10 is increased.

[0112] The temperature detected by the temperature detector 31 is gradually increased. At times t1 to t7, the load factor of the motor 10 is temporarily increased, whereby the rotational speed of the motor 10 is increased. The state acquisition section 62 acquires the operation state of the motor 10 and the temperature output from the temperature detector 31 during the period when the rotational speed of the motor 10 is gradually increased. More specifically, the state acquisition section 62 acquires the load factor of the motor 10, the rotational speed of the motor 10, and the temperature output from the temperature detector 31 at predetermined small time intervals, and stores them in the storage section 51. In the present embodiment, the temperature of the outside air is fixed, but the present embodiment is not limited to this. The state acquisition section 62 can also detect the temperature of the outside air at small time intervals from the outside air temperature detector 33.

[0113] Referring to Figure 1 , the state acquisition section 62 acquires the torque command included in the operation command generated by the operation control section 43 of the control device 41. The state acquisition section 62 can calculate the load factor of the motor 10 from the torque command. For example, the operation control section 43 has a position controller and a speed controller. The position controller calculates a speed command from a position command based on an operation program. The speed controller calculates a torque command from the speed command. The current supplied to the motor 10 is determined from the torque command. The operation control section 43 sends the torque command or the current command to the drive device 44, whereby the motor 10 is supplied with power. In order to make the torque command correspond to the load factor of the motor 10, the state acquisition section 62 can calculate the load factor from the torque command.

[0114] The parameter calculation section 63 calculates the parameters of the model 10a of the motor based on the variables acquired by the state acquisition section 62. The parameter calculation section 63 of the present embodiment calculates the parameters including the heat capacities C1, C2, C3, C4, C5 and the coefficients ha, hb, hc1, hc2, hc3, hd related to heat transfer based on the amount of heat generated in the coil 16 and the stator core 20 and the temperature detected by the temperature detector 31. In addition, the parameter calculation section 63 calculates the constants k1, k2 in the equations (6) and (7) as parameters. The parameter calculation section 63 calculates the parameters so that the temperature change of the model 31a of the temperature detector at the time of simulation approaches the actual temperature change.

[0115] The parameter calculation section 63 sets initial values of the respective parameters. The initial values of the parameters can be set by any method. The parameter calculation section 63 includes a loss calculation section that calculates the amount of heat generated by the primary copper loss of the coil 16 and the amount of heat generated by the iron loss of the stator core 20. The function of the loss calculation section of the parameter calculation section 63 is the same as that of the loss calculation section 54 of the estimation section 53. Therefore, the parameter calculation section 63 uses the loss calculation section 54 of the estimation section 53 in the calculation of the amount of heat generated. The loss calculation section 54 calculates the primary copper loss P c1 and the iron loss P i of the motor 10 based on the rotational speed of the motor 10 and the load factor of the motor 10 acquired by the state acquisition section 62 using Table 1 and the equations (6) to (10). In the equations (6) and (7) for calculating the primary copper loss P c1 and the iron loss P i , the constants k1, k2 are included. Also, the loss calculation section 54 calculates the loss in a predetermined small time dt, that is, the amount of heat generated in the small time. In this way, the loss calculation section 54 calculates the primary copper loss P c1 and the iron loss P i in the equations (1) and (2) based on the measured values including the operation command (load factor) of the motor and the output of the rotational position detector 32.

[0116] The parameter calculation section 63 includes a temperature calculation section that estimates the temperature of the temperature detector using the model of the motor. The function of the temperature calculation section of the parameter calculation section 63 is the same as that of the temperature calculation section 55 of the estimation section 53. Therefore, the parameter calculation section 63 uses the temperature calculation section 55 of the estimation section 53 in the estimation of the component temperatures. The temperature calculation section 55 estimates the temperature of the temperature detector 31 based on the model 10a of the motor using the respective parameters and the loss calculated by the loss calculation section 54. That is, the temperature of the model 31a of the temperature detector is estimated by simulation.

[0117] The temperature calculation section 55 can estimate the temperature change over time detected by the temperature detector 31 after the motor 10 is started to be driven, based on the temporarily set parameters. The temperature of each component of the model of the motor 10 can be calculated using the differential equations of the above-described equations (1) to (5). The initial value of the temperature of each component of the model can be set to the outside air temperature, i.e., the room temperature, at the time when the motor 10 is started to be driven, for example.

[0118] The evaluation section 66 of the parameter calculation section 63 performs temperature evaluation of the model 31a of the temperature detector by comparing the temperature of the model 31a of the temperature detector calculated by the temperature calculation section 55 with the temperature actually measured by the temperature detector 31. The evaluation section 66 evaluates the parameters temporarily set in the model 10a of the motor. The evaluation section 66 of the present embodiment does not evaluate variables other than the temperature of the model 31a of the temperature detector, and only evaluates the temperature of the model 31a of the temperature detector. For example, in addition to the temperature detector 31, a temperature detector can be further installed in a component other than the coil 16 to detect the actual temperature. The temperatures of a plurality of temperature detectors can be compared with the simulated temperature. However, in the example here, as long as the temperature change of the model 31a of the temperature detector approaches the actual temperature change, the temperature of at least one of the temperatures of the other components is not evaluated.

[0119] Next, the parameter changing section 67 of the parameter calculation section 63 changes the parameters based on the evaluation result of the evaluation section 66. Then, based on the changed parameters, the loss calculation performed by the loss calculation section 54, the temperature calculation of the model of the temperature detector performed by the temperature calculation section 55, the evaluation performed by the evaluation section 66, and the parameter changing performed by the parameter changing section 67 are repeatedly performed by the same calculations as described above. When the evaluation performed by the evaluation section satisfies a predetermined condition, the final parameters can be determined.

[0120] Here, the number of combinations of the plurality of parameters in the model 10a of the motor is very large. The plurality of parameters can be determined by a method of machine learning. For example, the plurality of parameters can be set by a method of Bayesian optimization.

[0121] In the Bayesian optimization, a target function to be evaluated is generated with respect to an explanatory variable including parameters to be input. Then, the parameter at which the target function is predicted to be minimum or maximum is searched and set. By repeatedly searching for the parameter, an optimal value of the parameter can be set. In addition, the range in which each parameter is set can be determined in advance.

[0122] Here, regarding the temperature of the temperature detector 31, the difference between the temperature of the model 31a of the temperature detector estimated by the model 10a of the motor and the temperature detected by the actual temperature detector 31 is set as the objective function. That is, regarding the temperature of the temperature detector 31, the objective function can use the difference between the predicted value calculated based on the temporarily set parameters according to the equations (1) to (5) and the actually measured value actually detected by the temperature detector 31. As the objective function, for example, the average of the difference in a small time or the like can be adopted. Then, the next parameter is searched for to make the objective function smaller.

[0123] In the Bayesian optimization, the search of the parameters and the evaluation of the parameters can be repeated. If the objective function is within a predetermined determination range, the evaluation section 66 can adopt the parameter value at that time. On the other hand, when the objective function deviates from the predetermined determination range, the search of the next parameter can be performed. In the method of the Bayesian optimization, the search is performed while predicting the region in which the solution exists, and thus the processing amount of the calculation can be suppressed.

[0124] Alternatively, in addition to the parameter setting based on the Bayesian optimization, the range in which each parameter is set can be predetermined. The parameter changing section 67 of the parameter calculation section 63 randomly sets a plurality of parameters within the parameter range. The temperature calculation section 55 estimates the temperature of the model 31a of the temperature detector according to the set parameters. The evaluation section 66 can evaluate the set parameters according to the actually measured value of the temperature acquired from the temperature detector 31. Such a parameter setting method is called a random search method.

[0125] Alternatively, the parameter changing section 67 can set the parameters at predetermined intervals within the range in which the parameters are set. The temperature calculation section 55 estimates the temperature of the model 31a of the temperature detector using the set parameters. The evaluation section 66 evaluates all combinations of the parameters set discretely. This method is called a grid search method.

[0126] In the random search method or the grid search method, as with the method of the Bayesian optimization, the evaluation section 66 can take the temperature of the temperature detector 31 as the evaluation object. If the objective function is within a predetermined determination range, the evaluation section 66 can adopt the parameter value at that time. Alternatively, the evaluation section 66 can adopt the parameter at which the objective function is optimal. The evaluation section 66 can determine the parameter that well coincides with the temperature actually detected by the actual temperature detector 31 as the parameter in the model 10a of the motor.

[0127] In the present embodiment, control is implemented in which the setting of the temporary parameters, the temperature estimation of the temperature detector based on the motor model, and the evaluation of the temporary parameters are repeatedly performed. The parameters are set so that the temperature change detected by the temperature detector 31 can be estimated with high accuracy. In the present embodiment, the temperature other than the temperature of the temperature detector can deviate from the actual temperature, and therefore, in the parameter evaluation, the temperature of the temperature detector that detects the temperature of the coil can be evaluated only. Thus, the parameters can be set in a short time with a small amount of calculation.

[0128] In Figure 4 , the operation in the no-load state is shown as the actual operation mode of the motor 10, but the present embodiment is not limited to this mode. When the parameters of the model 10a of the motor are determined, it is preferable to operate the motor 10 in various operation states and acquire the operation states of the motor 10.

[0129] Figure 5 The second operation mode in which the motor is actually driven in order to set the parameters of the model of the motor is shown. In the second operation mode, the increase and decrease of the load factor of the motor 10 are repeatedly performed. The load factor of the motor 10 is greatly changed, and thus the rotational speed of the motor is changed. The temperature detected by the temperature detector 31 is sharply increased or decreased. That is, in the second operation mode, it is an operation mode in which the temperature of the motor is sharply changed.

[0130] In Figure 5 , the load factor of the motor 10 is increased from 0% to 100% at each of the times from time t11 to time t20. The rotational speed of the motor is increased, and the temperature detected by the temperature detector 31 is increased. After a predetermined time elapses, the load factor of the motor 10 is decreased to 0%. The rotational speed of the motor 10 is decreased, and the temperature detected by the temperature detector 31 is decreased. The state acquisition unit 62 can acquire the operation command, the rotational speed, and the temperature output from the temperature detector 31 during the operation in which the increase and decrease of the load factor of the motor 10 are repeatedly performed.

[0131] In Figure 4 , the first operation mode in the no-load state or Figure 5 , the second operation mode in which the temperature is sharply changed, the temperature estimated by the estimation unit 53 is likely to have an error. By driving the motor in the first operation mode or the second operation mode to set the parameters of the model of the motor, the parameters can be adjusted according to the conditions of various loads. As a result, the parameters with which the temperature of the temperature detector can be estimated with high accuracy in various operation modes can be calculated.

[0132] In the above-described embodiment, the coil including the winding is exemplified as the component of the motor for estimating the temperature, but the present application is not limited to this. Any component of the motor can be used as the component for estimating the temperature. Referring to Figure 3 , for example, the stator core, the rotor, or the air layer can be selected as the component for estimating the temperature. At this time, the temperature detector is arranged to detect the actual temperature of the component whose temperature is estimated by the temperature estimation device. For example, when the temperature estimation device estimates the temperature of the stator core, the temperature detector can be attached to the stator core to detect the temperature of the stator core.

[0133] In the temperature estimation device of the present embodiment, it is only necessary to estimate the temperature of one component with high accuracy. Therefore, at least some of the plurality of heat capacities and the plurality of heat transfer-related coefficients can be set to values different from the actual heat capacities and the actual heat transfer-related coefficients. The operator selects one component of the motor, and the temperature detector is attached to the component. The parameter setting device can set the heat transfer-related coefficients and the like by the same method as the above-described parameter setting for detecting the temperature of the coil. The evaluation section of the parameter calculation section evaluates the temperature of the model of the temperature detector by comparing the temperature of the model of the temperature detector with the temperature obtained by the actual temperature detector. Furthermore, the parameter changing section can change the parameters based on the result of the evaluation section. In addition, when the parameters satisfy a predetermined condition, the evaluation section can determine the parameters as final parameters.

[0134] In the above-described embodiment, the synchronous motor having the permanent magnet in the rotor is exemplified, but the present application is not limited to this. The model of the motor in the present embodiment can be applied to the induction motor having no permanent magnet in the rotor.

[0135] Figure 6 A model of a second motor of the present embodiment is shown. The second motor is an induction motor. The rotor of the induction motor includes a cage conductor formed of stainless steel or copper. The rotor of the induction motor includes no permanent magnet. The cage conductor is fixed to the shaft and rotates integrally with the shaft. In the induction motor, an induced current flows in the inside of the cage conductor by the magnetic force generated by the stator coil. A magnetic field is generated around the cage conductor to rotate the rotor.

[0136] In the induction motor, the current flows in the cage conductor, and thus a secondary copper loss P c2 corresponding to Joule heat caused by the current flowing in the cage conductor is generated. In the model 27a of the second motor, heat generation due to the secondary copper loss is generated in the rotor. The heat capacities of the components of the second motor and the heat transfer-related coefficients between the components are the same as those of the model 10a of the first motor.

[0137] The differential equation of the temperature of each component in the model 27a of the second motor is different from the differential equation of the rotor temperature in the model 10a of the first motor. The differential equation of the change in the rotor temperature is the following equation (11).

[0138] [Equation 5]

[0139]

[0140] P c2 : secondary copper loss

[0141] In the equation (11), the equation (4) of the model 11a of the rotor of the first motor is added with the heat generation amount of the secondary copper loss P c2 . The other differential equations of the changes in the temperatures of the coil, the stator core, the air layer, and the temperature detector are the same as those in the thermal model of the first motor.

[0142] Here, the method of calculating the heat generation amount of the secondary copper loss is described. In order to calculate the secondary copper loss generated in the rotor conductor, the current flowing in the conductor needs to be estimated.

[0143] Figure 7 A graph showing the d-axis current and the q-axis current when the vector control of the induction motor is performed. In Figure 7 , the d-axis current and the q-axis current flowing in the stator are indicated by arrows. The d-axis indicates the current for exciting the coil, and the q-axis indicates the current for generating the torque of the motor. The overall current I flowing in the stator core is calculated by vector addition of the d-axis current I 1d and the q-axis current I 1q . Here, when the exciting current is small, the angle θ between the current I and the d-axis current I 1d is 45°.

[0144] Figure 8 A graph showing the d-axis current and the q-axis current when the exciting current is large. Figure 8 is a graph when the exciting current exceeds the maximum current. When the exciting current is large, the angle θ of the current I with respect to the d-axis current I 1d is larger than 45°. In the present embodiment, the equation for calculating the q-axis current of the primary-side coil is changed according to the magnitude of the d-axis current. As shown in the equations (12) and (13), the q-axis current I e is calculated according to the predetermined exciting current I 1q .

[0145] [Equation 6]

[0146] When

[0147] ​I 1q =I…(12)

[0148] when hour

[0149]

[0150] I 1q : q-axis current on the primary side

[0151] I e Magnetizing current

[0152] I: Current

[0153] Here, by measuring the current I at maximum output... m The current I is calculated by multiplying it by the motor's load rate. Then, the q-axis current I of the primary winding can be used as a reference. 1q The secondary copper loss P is calculated using the following equation (14). c2 .

[0154] [Mathematical Expression 7]

[0155]

[0156] P c2 Secondary copper loss

[0157] r2: Secondary resistor

[0158] M: Mutual inductance

[0159] L2: Secondary inductor

[0160] Here, inductance L2 is the inductance of the squirrel-cage conductor, and mutual inductance M is the mutual inductance between the squirrel-cage conductor and the stator coil. These inductances L2 and M, as well as the secondary resistance r2 of the conductor, can be determined beforehand. The total loss P in the induction motor... t and a single copper loss P c1 It can be calculated in the same way as the total loss and primary copper loss in a synchronous motor. Furthermore, the iron loss P... i It can be calculated using the following formula (15).

[0161] [Mathematical Expression 8]

[0162] P i =P t -P c1 -P c2 …(15)

[0163] P i Iron loss

[0164] Thus, in the second motor, the primary copper loss, the iron loss, and the secondary copper loss can also be calculated. In addition, the temperature of the temperature detector for detecting the temperature of the stator coil and the like constituent part can be estimated using the model 27a of the second motor. Further, the parameter setting unit 61 can set the parameter values such as the heat capacity included in the model of the second motor, similarly to the setting of the parameter values included in the model of the first motor.

[0165] Figure 9 A graph showing the temperature of the temperature detector estimated by the estimation unit using the parameters set by the parameter setting unit of the present embodiment is shown in FIG. 8. In FIG. 8, the horizontal axis represents time, and the vertical axis represents temperature. In FIG. 8, the temperature of the temperature detector estimated using the parameter group A is shown by a solid line, and the temperature of the temperature detector estimated using the parameter group B is shown by a broken line. Figure 9 Graphs at the time of simulation using the parameter group A and the parameter group B, which are different from each other, are shown in FIG. 9. Here, an example of the second motor is shown. The parameter group A and the parameter group B are set by the parameter setting unit 61. Table 2 shows the parameters included in the parameter group A and the parameter group B.

[0166] [Table 2]

[0167] Table 2 Parameters

[0168] Unit of the coefficient related to heat transfer: [W / K]

[0169] Unit of mass: [kg]

[0170]

[0171]

[0172] The parameter group A and the parameter group B are obtained by driving the second motor in mutually different operation modes. In Table 2, the coefficient related to heat transfer obtained by multiplying the heat transfer coefficient between each constituent part of the motor by the contact area is shown. In addition, the heat capacity is calculated by multiplying the specific heat of the material of each constituent part by the mass. The specific heat of each material can be determined in advance, and thus, in Table 2, the mass m of the constituent part used for calculating the heat capacity is shown. If the parameter group A and the parameter group B are compared, it is found that the values of some of the parameters such as the coefficient related to heat transfer hc2, hd, and the mass m4 of the rotor are greatly different between the two parameter groups A and B.

[0173] On the other hand, if Figure 9 it is found that the temperature of the temperature detector estimated using the parameter group B and the temperature of the temperature detector estimated using the parameter group A are in good agreement. In particular, the temperature change is in good agreement in both the period during which the temperature rises and the period during which the temperature fluctuates within a predetermined range. Further, the temperature change estimated by the estimation unit 53 is in good agreement with the temperature change detected by the temperature detector 31 when the motor 10 is actually driven. Figure 9 The temperature change shown in FIG. 9 is in good agreement with the temperature change detected by the temperature detector 31 when the motor 10 is actually driven.

[0174] There are parameters whose values differ greatly between the parameter group A and the parameter group B. Therefore, it is known that the values of at least one of the parameter group A and the parameter group B are different from the parameter group in the actual motor. In particular, it is known that at least a part of the plurality of heat capacities and the plurality of heat transfer-related coefficients are set to values different from the actual heat capacities or the actual heat transfer-related coefficients. For example, it is known that at least one of the heat transfer-related coefficients of the coefficient hc2 of the parameter group A and the coefficient hc2 of the parameter group B deviates from the actual heat transfer-related coefficient.

[0175] Thus, in the temperature estimation device of the present embodiment, even if at least a part of the plurality of parameters is different from the actual values, the temperature of the temperature detector can be estimated with high accuracy. In addition, the parameter setting device of the present embodiment can set the parameters of the model of the motor. Furthermore, as described above, the parameter setting device calculates the heat capacities and the heat transfer-related coefficients, and as a result, all of the heat capacities and all of the heat transfer-related coefficients can be the same as the actual heat capacities and the actual heat transfer-related coefficients. Also, when the temperatures of the constituent parts are estimated by the estimation unit, the temperatures of all of the constituent parts can correspond to the actual temperatures of the constituent parts with high accuracy.

[0176] The model of the motor in the above-described embodiment is constituted by the model of the coil, the model of the stator core, the model of the temperature detector, the model of the air layer, the model of the rotor, and the model of the external air, but is not limited to this. The model of the motor can also include models of other constituent parts. For example, the model of the motor can include a model of a frame that supports the stator and the rotor, a model of a bearing, and a model of a shaft that supports the rotor, and the like. Alternatively, the model of the motor can not include a part of the models. For example, the model of the motor can not include the model of the air layer.

[0177] By excluding the model of the frame and the model of the shaft and the like from the model of the motor, the amount of calculation for estimating the temperature of the temperature detector or the amount of calculation for setting the parameters can be reduced. The model of the motor of the present embodiment does not include the model of the frame and the model of the shaft, which have relatively large heat capacities, but as described above, the temperature simulation of the temperature detector can be performed with high accuracy. Figure 9

[0178] ​However, in the temperature estimation device described above, when the estimation unit estimates the temperature of the temperature detector using the model of the motor, the copper loss, the iron loss, the coefficient related to heat transfer, and the heat capacity are adopted as fixed values regardless of the temperature of the constituent part of the motor. However, these losses and parameters sometimes change in value as the temperature of the constituent part of the motor changes. Next, an embodiment in which at least one of the copper loss, the iron loss, the coefficient related to heat transfer, and the heat capacity in the model of the motor is corrected according to the temperature of the constituent part of the motor will be described. The correction of each parameter is performed according to a correction value. Here, the model 10a of the first motor (refer to Figure 3 ) and the model 27a of the second motor (refer to Figure 6 ) will be described as examples.

[0179] First, the correction of the iron loss generated in the stator core will be described. The loss at no load of the motor is generated due to the iron loss in the stator core. The iron loss is generated due to the change in magnetic flux generated in the stator core. Here, if the rotor temperature of the motor rises, the temperature of the magnet included in the rotor rises. The magnet has a characteristic in which the magnetic force becomes weaker if the temperature rises. Therefore, if the temperature of the magnet rises, the magnetic flux generated in the stator core becomes smaller. That is, if the rotor temperature rises, the iron loss becomes smaller.

[0180] Figure 10 A graph showing a correction value for correcting the loss at no load with respect to the rotor temperature is shown. In the iron loss correction, the correction is performed in such a manner that the higher the rotor temperature, the smaller the iron loss. In the present embodiment, the loss at no load is corrected depending on the rotor temperature. Referring to Figure 1 , the loss calculation unit 54 of the estimation unit 53 performs the correction in such a manner that the higher the rotor temperature, the smaller the loss at no load of the motor. The loss calculation unit 54 decides the coefficient sn according to the rotor temperature. Also, the loss calculation unit 54 multiplies the loss at no load by the coefficient sn.

[0181] In the example shown in Figure 10 , the rotor temperature T4 is shown as ranging from 20°C, which is room temperature, to 130°C, which is the maximum value. The coefficient sn when the rotor temperature is 20°C is 100%, and the coefficient sn when the rotor temperature is the maximum value is snx%. The coefficient snx corresponds to a correction value for correcting so that the higher the rotor temperature, the smaller the iron loss. The magnitude of the coefficient snx when the rotor temperature is the maximum value depends on the shape and the material and the like of the characteristics in the rotor core and the magnet. The coefficient snx can be determined in advance by an operator. Alternatively, as will be described later, the coefficient snx when the rotor temperature is the maximum value can be set by a parameter setting device.

[0182] Referring to Figure 1 , Figure 3 , and Figure 10, the loss calculation section 54 of the estimation section 53 calculates the coefficient sn based on the rotor temperature T4 calculated in the model 10a of the motor. Table 1 is a loss map indicating a loss that becomes a reference and a current. Table 1 is, for example, a loss map when the rotor temperature is 20°C and the coefficient sn is 100%.

[0183] The loss calculation section 54 can calculate the loss at no load P n obtained by multiplying the loss at no load P n obtained from the loss map of Table 1 by the coefficient sn as the corrected loss at no load. The loss calculation section 54 calculates the iron loss using the corrected loss at no load. According to Equation (6), if the rotor temperature rises, the loss at no load P t becomes smaller. As a result, according to Equation (10), the iron loss P i becomes smaller. The temperature calculation section 55 can calculate the temperature of the constituent part including the temperature detector based on the corrected iron loss. In this way, it is possible to take into account the magnitude of the iron loss that changes depending on the rotor temperature.

[0184] In addition, the correction of the iron loss generated in the stator core is not limited to the above-described manner. The iron loss can be corrected depending on the rotor temperature by any method. For example, the following correction can be performed: the iron loss calculated using the temperature of the rotor that becomes a reference is multiplied by a coefficient based on the rotor temperature.

[0185] Next, the correction of the primary copper loss generated in the coil will be described. The primary copper loss of the motor corresponds to the Joule heat generated in the winding of the stator coil. As indicated by Equation (8), the primary copper loss is calculated by the product of the primary resistance r1 in the stator coil and the square of the current I. Here, the winding of the coil has a characteristic that the resistance becomes larger if the temperature rises. Therefore, if the coil temperature rises, the primary copper loss becomes larger.

[0186] Figure 11 a graph indicating the value of the primary resistance with respect to the coil temperature. Referring to Figure 1 , Figure 3 , and Figure 11 , in the correction of the primary copper loss, the correction is performed in such a manner that the primary copper loss becomes larger as the coil temperature is higher. In the present embodiment, the primary resistance is corrected depending on the coil temperature. The loss calculation section 54 determines the primary resistance r1 based on the coil temperature. Also, the loss calculation section 54 calculates the primary copper loss based on the primary resistance.

[0187] In Figure 11In the example shown, the coil temperature T1 is indicated as ranging from 20°C, which is room temperature, to 130°C, which is the maximum value. The primary resistance rla at the coil temperature of room temperature can be measured in advance to determine. In addition, the primary resistance rlb at the coil temperature of the maximum value can be measured in advance to determine. The primary resistances rla, rlb depend on the material, shape, and length of the winding of the coil, and the like. Alternatively, the primary resistances rla, rlb can be set by the parameter setting device, as described later. The primary resistances rla, rlb correspond to correction values for correcting the primary copper loss to be larger as the coil temperature is higher.

[0188] The loss calculation section 54 of the estimation section 53 calculates the corrected primary resistance r1 based on the coil temperature T1 calculated in the model 10a of the motor. The loss calculation section 54 calculates the primary copper loss based on Equation (8) using the corrected primary resistance r1. If the coil temperature rises, the primary resistance r1 becomes larger, and thus the primary copper loss becomes larger. The temperature calculation section 55 can calculate the temperature of the constituent part including the temperature detector based on the corrected primary copper loss.

[0189] In addition, the correction of the primary copper loss generated in the coil is not limited to the above-described manner. Any correction method of correcting the primary copper loss based on the coil temperature can be employed. For example, a correction of multiplying the calculated copper loss by a coefficient based on the coil temperature can be performed.

[0190] Next, the correction of the coefficient related to the heat transfer between the constituent parts will be described. The heat transfer coefficient generally has a characteristic that the heat transfer coefficient becomes larger as the temperature difference between the constituent parts becomes larger. In addition, the contact area between the constituent parts is fixed. Therefore, in the correction of the coefficient related to the heat transfer, the correction can be performed in a manner that the coefficient related to the heat transfer becomes larger as the temperature difference between the constituent parts becomes larger.

[0191] Figure 12 A graph showing a constant for correcting the coefficient related to the heat transfer based on the temperature difference between the constituent parts of the motor is shown. The horizontal axis shows the temperature difference between the constituent parts of the motor as ranging from 0°C, which is the minimum value, to 130°C, which is the maximum value. The vertical axis shows the constant sh for correcting the coefficient related to the heat transfer as a reference. The coefficient related to the heat transfer as the reference can be determined in advance. Here, the coefficient related to the heat transfer at the temperature difference of 0°C between the constituent parts is determined as the coefficient related to the heat transfer as the reference. The constant sh at the temperature difference of 0°C between the constituent parts is 1. At the maximum temperature difference between the constituent parts, the constant sh is shx.

[0192] Referring to Figure 1 , Figure 3 and Figure 12The temperature calculation unit 55 of the estimation unit 53 calculates the corrected heat transfer correlation coefficient h' by multiplying the reference heat transfer correlation coefficient h by a coefficient based on the constant sh, as shown in the following formula (16).

[0193] [Mathematical Expression 9]

[0194]

[0195] h': Corrected heat transfer correlation coefficient

[0196] h: The coefficient related to the heat transfer of the reference.

[0197] (T a -T b Temperature difference between components

[0198] According to equation (16), when the temperature difference between the constituent parts is 0°C, the corrected heat transfer correlation coefficient is set as the baseline heat transfer correlation coefficient. The constant shx when the temperature difference between the constituent parts is at its maximum corresponds to the correction value of the heat transfer correlation coefficient, which is adjusted according to the temperature difference between the constituent parts. Figure 12 In the example shown, the constant shx is greater than 1, and the greater the temperature difference between the constituent parts, the larger the coefficient multiplied by the reference heat transfer correlation coefficient. That is, Figure 12 The constant shx shown corresponds to a correction value used to adjust the coefficient of heat transfer as the temperature difference between the constituent parts increases. The constant shx is, for example, a value greater than 0 and less than approximately 3. The constant shx can be predetermined. Alternatively, as described later, the constant shx can be set using a parameter setting device.

[0199] The temperature calculation unit 55 of the estimation unit 53 calculates the temperature difference between each component. The temperature calculation unit 55 obtains the baseline heat transfer correlation coefficient between the components. The temperature calculation unit 55 calculates the corrected heat transfer correlation coefficient according to equation (16). The temperature calculation unit 55 uses the corrected heat transfer correlation coefficient to calculate the temperature of each component.

[0200] For example, the temperature calculating section 55 calculates a temperature difference between the temperature Tl of the model of the coil and the temperature T2 of the model of the stator core in the model 10a of the motor. A coefficient related to heat transfer between the coil and the stator core is determined in advance. The temperature calculating section 55 calculates a corrected coefficient related to heat transfer according to Equation (16). Also, the temperature calculating section 55 calculates the amount of change in the temperature Tl of the model of the coil and the amount of change in the temperature T2 of the model of the stator core in a small time in the above-mentioned Equations (1) and (2) using the corrected coefficient related to heat transfer. In this way, the temperature of the constituent part can be calculated taking into account the coefficient related to heat transfer that changes depending on the temperature difference between the constituent parts.

[0201] Further, in the above-mentioned manner of correcting the coefficient related to heat transfer, the correction is made such that the larger the temperature difference between the constituent parts, the larger the coefficient related to heat transfer, but is not limited to this manner. In the parameter setting device described later, when the constant shx as the correction value is calculated, there is a case where the larger the temperature difference between the constituent parts, the smaller the coefficient related to heat transfer. That is, there is a case where the constant shx is less than 1. At this time, the estimating section can correct the coefficient related to heat transfer such that the larger the temperature difference between the constituent parts, the smaller the coefficient related to heat transfer. In this way, the estimating section can perform correction that changes the coefficient related to heat transfer depending on the temperature difference between the constituent parts.

[0202] Next, correction of the heat capacity of the constituent part will be described. The heat capacity generally has a characteristic that the higher the temperature of the constituent part, the larger the heat capacity. Therefore, in the correction of the heat capacity of the constituent part, the correction can be made such that the higher the temperature of the constituent part, the larger the heat capacity.

[0203] Figure 13 A graph showing a constant for correcting the heat capacity of the constituent part with respect to the temperature of the constituent part is shown. The horizontal axis shows the temperature of the constituent part of the motor from the minimum value of 0°C to the maximum value of 130°C. The vertical axis shows the constant sc for correcting the heat capacity as a reference. The heat capacity as a reference can be determined in advance. In the example here, the heat capacity when the temperature of the constituent part is 0°C is the reference heat capacity. The constant sc when the temperature of the constituent part is 0°C is 1. The constant sc when the temperature of the constituent part is the maximum is scx.

[0204] Referring to Figure 1 , Figure 3 and Figure 13 , the temperature calculating section 55 of the estimating section 53 calculates the corrected heat capacity C' by multiplying the reference heat capacity C by a coefficient based on the constant sc as shown in the following Equation (17).

[0205] [Equation 10]

[0206]

[0207] C': corrected heat capacity

[0208] C: reference heat capacity

[0209] T c : temperature of the constituent

[0210] According to the equation (17), the corrected heat capacity is set to the reference heat capacity when the temperature of the constituent is 0°C. The constant scx at the maximum temperature of the constituent corresponds to a correction value for changing the heat capacity according to the temperature of the constituent. In the example shown in FIG. 8, the constant scx is greater than 1, and the higher the temperature of the constituent, the greater the coefficient multiplied by the reference heat capacity. That is, the higher the temperature of the constituent, the greater the heat capacity. Figure 13 The constant scx shown in FIG. 8 corresponds to a correction value for correcting the heat capacity to be greater as the temperature of the constituent is higher. The constant scx is, for example, a value greater than 0 and less than about 3. The constant scx can be determined in advance. Alternatively, as described later, the constant scx can be set by the parameter setting device. Figure 13

[0211] The temperature calculation section 55 of the estimation section 53 acquires the temperature of the constituent and the reference heat capacity. The temperature calculation section 55 calculates the corrected heat capacity of each constituent according to the equation (17). The temperature calculation section 55 can calculate the temperature of each constituent using the corrected heat capacity using the equations (1) to (5) described above. In this way, the temperature of the constituent can be estimated taking into account the heat capacity that changes according to the temperature of the constituent.

[0212] Further, in the above-described manner of correcting the heat capacity, the correction is performed in a manner that the heat capacity is greater as the temperature of the constituent is higher, but is not limited to this manner. In the parameter setting device described later, when the constant scx as a correction value is calculated, there is a case where the heat capacity is smaller as the temperature of the constituent is higher. That is, there is a case where the constant scx is less than 1. At this time, the estimation section can correct the heat capacity to be smaller as the temperature of the constituent is higher. In this way, the estimation section can perform correction that changes the heat capacity according to the temperature of the constituent.

[0213] The above-described correction of the iron loss, the correction of the copper loss, the correction of the coefficient related to heat transfer, and the correction of the heat capacity can be implemented in combination with each other. Alternatively, any one of the corrections can be implemented. At least one of the iron loss, the primary copper loss, the coefficient related to heat transfer, and the heat capacity can be corrected according to the temperature of each constituent. As a result, the temperature of the temperature detector can be estimated more accurately.

[0214] Further, regarding the Figure 6 ​The correction of the secondary copper loss in the model 27a of the second electric motor shown can be performed in the same manner as the correction of the primary copper loss. Also, the temperature of the temperature detector installed in an arbitrary constituent part can be calculated using the corrected secondary copper loss.

[0215] In this way, in the model of the electric motor, at least one of the thermal capacity, the coefficient related to heat transfer, the iron loss, and the copper loss can be corrected according to the correction value. The correction value for correcting the thermal capacity and the like can be set by the parameter setting device described above, as with the setting of the parameters such as the thermal capacity and the coefficient related to heat transfer. As with the coefficient related to heat transfer, the correction value can be set by the parameter setting device described above by treating the correction value as an unknown parameter.

[0216] Referring to Figure 1 The parameter setting section 61 of the temperature estimation device 2 can set the correction value, for example, by a method such as Bayesian optimization. The parameter setting section 61 can calculate the respective correction values in the same manner as the setting of the coefficient related to heat transfer and the thermal capacity. For example, the parameter setting section 61 sets the parameters such as the coefficient related to heat transfer and the correction value to temporary initial values. The state acquisition section 62 acquires the driving state of the electric motor. The loss calculation section 54 of the estimation section 53 calculates the loss according to the driving state such as the rotational speed of the electric motor 10 acquired by the state acquisition section 62. The temperature calculation section 55 of the estimation section 53 estimates the temperature of the model 31a of the temperature detector using the model of the electric motor according to the loss calculated by the loss calculation section 54. At this time, the loss and the thermal capacity and the like corrected according to the correction value are used.

[0217] The evaluation section 66 of the parameter calculation section 63 evaluates the temperature of the model 31a of the temperature detector calculated using the parameters and the correction value set temporarily. The evaluation section 66 evaluates the temperature of the model 31a of the temperature detector, but does not evaluate variables other than the temperature of the model 31a of the temperature detector. If the temperature of the model 31a of the temperature detector is within a predetermined determination range, the parameter calculation section 63 can adopt the parameters and the correction value at this time. For example, the parameter calculation section 63 can adopt the parameters and the correction value at this time when the difference between the temperature of the model 31a of the temperature detector and the temperature output from the actual temperature detector 31 is small. On the other hand, when the temperature of the model 31a of the temperature detector deviates from the predetermined determination range, the parameter changing section 67 changes the parameters and the correction value according to the evaluation result of the evaluation section 66. In this way, the setting of the parameters and the correction value and the evaluation of the temperature of the model of the temperature detector can be repeatedly performed.

[0218] The parameter calculation unit 63 can set a plurality of heat capacities and a plurality of heat transfer-related coefficients, and can set the correction value. The parameter calculation unit 63 can set the correction value in the same manner as the setting method of the heat capacity and the heat transfer-related coefficient. The correction value set by the parameter calculation unit 63 can be set to the same value as the actual correction value, or can be set to a different value from the actual correction value. That is, the correction value set by the parameter calculation unit 63 can be a value deviating from the actual correction value. For example, with reference to Figure 11 , the primary resistance r1a, r1b as the correction value for calculating the primary resistance that changes depending on the coil temperature can be set to a different value from the actual primary resistance value, or can be set to the same value. As for the correction value, it is only necessary to be able to accurately estimate the temperature of the temperature detector.

[0219] The above-described embodiments can be appropriately combined. In the above-described respective drawings, the same symbols are attached to the same or equivalent portions. Further, the above-described embodiments are examples, and do not limit the invention. In addition, in the embodiments, modifications of the embodiments shown in the claims are included.

[0220] Symbol Explanation

[0221] 2 Temperature Estimation Device

[0222] 10 Motor

[0223] 10a Model of Motor

[0224] 11 Rotor

[0225] 11a Model of Rotor

[0226] 12 Stator

[0227] 16 Coil

[0228] 16a Model of Coil

[0229] 20 Stator Core

[0230] 20a Model of Stator Core

[0231] 27a Model of Motor

[0232] 31 Temperature Detector

[0233] 31a Model of Temperature Detector

[0234] 32 Rotation Position Detector

[0235] 35a Model of Air Layer

[0236] 43 Motion Control Unit

[0237] 54 Loss Calculation Unit

[0238] 55 temperature calculation section

[0239] 61 parameter setting section

[0240] 62 state acquisition section

[0241] 63 parameter calculation section

[0242] 66 evaluation section

[0243] 67 parameter change section

Claims

1. A parameter setting device that sets a parameter included in a model of a motor, the parameter being used to estimate a temperature of a temperature detector that detects a temperature of a component that constitutes the motor, characterized by comprising: a state acquisition section that acquires an operation command of the motor generated while actually driving the motor and a temperature output from the temperature detector; and a parameter calculation section that calculates the parameter so that a temperature change of a model of the temperature detector calculated by the model of the motor corresponds to an actual temperature change, wherein the model of the motor includes a model of a rotor, a model of a stator core, a model of a coil, and a model of the temperature detector as models of components of the motor, wherein only the model of the temperature detector is determined in the model of the motor, wherein the parameter includes a heat capacity set for the models of the components and a coefficient related to heat transfer between the models of the components, wherein the parameter calculation section includes: a loss calculation section that calculates a heat generation amount of the coil due to a primary copper loss and a heat generation amount of the stator core due to an iron loss, according to the operation command; a temperature calculation section that calculates a temperature of the model of the temperature detector using the model of the motor, according to the heat generation amount of the coil and the heat generation amount of the stator core; an evaluation section that evaluates the temperature of the model of the temperature detector by comparing the temperature of the model of the temperature detector with the temperature of the temperature detector acquired by the state acquisition section; and a parameter changing section that changes a value of the parameter according to an evaluation result of the evaluation section, wherein the evaluation section evaluates the temperature of the model of the temperature detector without evaluating a variable other than the temperature of the model of the temperature detector, and wherein the parameter calculation section sets a part of the plurality of heat capacities and the plurality of coefficients related to heat transfer to values different from actual heat capacities or actual coefficients related to heat transfer, and sets other parameters other than the part of the parameters to values substantially the same as the actual heat capacities or the actual coefficients related to heat transfer.

2. The parameter setting device according to claim 1, wherein the state acquisition section acquires the operation command and the temperature output from the temperature detector during a period in which an operation in which a load factor of the motor is repeatedly increased and decreased is performed.

3. The parameter setting device according to claim 1 or 2, wherein the state acquisition section acquires the operation command and the temperature output from the temperature detector during a period in which an operation in which the motor speed is gradually increased in a no-load state is performed.

4. The parameter setting device according to claim 1 or 2, wherein the parameter calculation section calculates the parameter by machine learning that sets a difference between a temperature of the model of the temperature detector estimated by the model of the motor and a temperature detected by an actual temperature detector as an objective function.

5. The parameter setting device according to claim 1, wherein the model of the motor is formed so as to correct at least one of the heat capacity, the coefficient related to heat transfer, the iron loss of the stator core, and the primary copper loss of the coil according to a correction value. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The correction value includes at least one of a correction value for correcting that the iron loss becomes smaller as the rotor temperature becomes higher, a correction value for correcting that the primary copper loss becomes larger as the coil temperature becomes higher, a correction value for correcting that a coefficient related to heat transfer varies depending on a temperature difference between the constituent parts, and a correction value for correcting that a heat capacity varies depending on a temperature of the constituent parts, The parameter changing section changes the correction value in accordance with the evaluation result of the evaluation section.

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