Control device and control system

Abstract

The present invention can obtain a control device that can suppress the decrease in the accuracy of temperature estimation due to aging. The control device (10) includes a correction unit (13) that corrects at least one of thermal resistance, calorific value and thermal capacity as physical quantities representing a thermal circuit model (30-1), the thermal circuit model including a thermal circuit of a rotating electrical machine (1), and the correction unit (13) uses measurement information of a temperature (T31) or a heat flow (U32) corresponding to a measurement position measured by a sensor unit (8) in the rotating electrical machine (1) to correct at least one of the thermal resistance, calorific value and thermal capacity corresponding to a measurement position.

Description

Technical Field

[0001] The present application relates to a control device that estimates the temperature of a rotating electrical machine and a control system using the control device. Background Art

[0002] As a conventional control device, there is a control device including: a temperature detection device that detects the temperature of a stator; and a temperature estimation device that estimates the temperature of the stator of the motor based on a thermal circuit model that represents the thermal characteristics of an actual motor as a rotating electrical machine and is composed of thermal resistance and heat generation inside the motor. In the conventional control device, it is known that the heat generation of the motor is corrected by multiplying the error between the detected temperature of the stator detected by the temperature detection device and the estimated temperature of the stator estimated by the temperature estimation device by a predetermined coefficient (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-82698 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the control device shown in Patent Document 1, the values ​​of thermal resistance and thermal capacity of the thermal circuit model used for temperature estimation need to be determined at the time of writing the control logic to the control device in the production process. Therefore, the values ​​of thermal resistance and thermal capacity of the thermal circuit model will not change after leaving the factory. Therefore, there is a problem that the thermal resistance, calorific value, and thermal capacity in the thermal circuit model cannot be corrected according to the changes in the thermal resistance, calorific value, and thermal capacity of the motor caused by aging, and the accuracy of the temperature estimation of the control device decreases during aging.

[0008] The present application has been made to solve the above-mentioned problems, and an object of the present application is to obtain a control device capable of suppressing a decrease in the accuracy of temperature estimation due to aging.

[0009] Solutions to Solve Problems

[0010] The control device according to the present application includes a correction unit that corrects at least one of thermal resistance, calorific value, and heat capacity as physical quantities representing a thermal circuit model, the thermal circuit model including a thermal circuit of a rotating electrical machine.

[0011] The correction unit corrects at least one of the thermal resistance, calorific value, and heat capacity corresponding to the measurement position using measurement information including temperature or heat flow corresponding to the measurement position measured by the sensor unit in the rotating electrical machine.

[0012] Effects of the Invention

[0013] In the control device configured as described above, it is possible to suppress a decrease in the accuracy of temperature estimation due to aging. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a block diagram showing a control system in Embodiment 1 of the present application.

[0015] Figure 2 It is a diagram showing the hardware configuration of the control system in the first embodiment of the present application.

[0016] Figure 3 This is a block diagram showing a part of the control device in the first embodiment of the present application.

[0017] Figure 4 This is a diagram showing a thermal circuit model of the entire electric motor used for temperature estimation by the control device in the first embodiment of the present application.

[0018] Figure 5 Yes means Figure 4 Diagram of a portion of the thermal loop model.

[0019] Figure 6 This is a partial diagram of a thermal circuit model used when correcting thermal resistance in the control device in the first embodiment of the present application.

[0020] Figure 7 This is a partial diagram of a thermal circuit model used when correcting the heating value in the control device in Embodiment 1 of the present application.

[0021] Figure 8 This is a partial diagram of a thermal circuit model used when correcting the heat capacity in the control device in the first embodiment of the present application.

[0022] Fig. 9 This is a flowchart of control by the control device in Embodiment 1 of the present application.

[0023] Fig.10 This is a flowchart of control of the control device in Embodiment 2 of the present application.

[0024] Fig.11 This is a diagram showing the output of the electric motor with respect to time in the control device in the second embodiment of the present application.

[0025] Fig.12 This is a diagram showing estimated temperatures with respect to time in the control device in the second embodiment of the present application.

[0026] Fig.13 This is a diagram showing the output of the electric motor with respect to time in the control device in the second embodiment of the present application.

[0027] Fig.14 This is a diagram showing estimated temperatures with respect to time in the control device in the second embodiment of the present application. DETAILED DESCRIPTION

[0028] Hereinafter, a drive control device according to an embodiment of the present application will be described in detail with reference to the drawings.

[0029] Implementation method 1.

[0030] Figure 1 This is a block diagram showing a control system in Embodiment 1 for implementing the invention according to the present application.

[0031] like Figure 1 As shown, the control system 100 includes: a motor 1 as a rotating electrical machine, an inverter 9 as a power converter, a control device 10 for controlling the inverter 9, a sensor 8 as a sensor unit, a rotation position detector 14, and a current detector 15. Figure 1 In the figure, the control system 100 as the motor system is a control system that drives the motor mounted on the electric vehicle using an inverter and a control device, for example. It should be noted that the control device 10 may be mounted inside the inverter 9 and integrated.

[0032] The motor 1 includes a stator 2 and a rotor 3 rotatably disposed facing the stator 2 with a gap therebetween. The stator 2 includes a stator core 4 and a stator winding 5. The rotor 3 includes a rotor core 6, a rotor winding 7, and a shaft 23. The rotor 3 may include a permanent magnet instead of the rotor winding 7 that generates a magnetic field.

[0033] In the stator 2 and the rotor 3, the sensor 8 as a temperature sensor and a heat flux sensor is arranged near the stator winding 5, the stator core 4, and the rotor winding 7 to measure the local temperature and heat flux in the motor 1. The installation position of the sensor 8 is not limited to the inside of the motor 1, and it can be installed at any position of the motor 1, such as on the surface of the motor 1. In addition, the sensor 8 does not necessarily need to be installed in the motor 1, as long as it can measure the temperature and heat flux on the motor 1 from a position away from the motor 1. It should be noted that the sensor 8 is not limited to a temperature sensor and a heat flux sensor, and it can also be a sensor that indirectly measures information required for measuring temperature or heat flux.

[0034] Furthermore, the motor 1 is provided with a rotation position detector 14 that detects the rotation position of the rotor 3 and a current detector 15 that detects the current flowing through the motor 1 as a detection current.

[0035] The control device 10 includes: a control unit 11, which controls the motor 1 using a thermal circuit model including a thermal circuit of the motor 1 as a rotating electrical machine; a calculation unit 12, which estimates the temperature of the rotating electrical machine as an estimated temperature using the thermal circuit model; and a correction unit 13, which corrects at least any one of thermal resistance, calorific value and heat capacity as physical quantities representing the thermal circuit model.

[0036] The calculation unit 12 and the correction unit 13 receive measurement information measured by the sensor 8 provided in the motor 1 and perform calculations described later.

[0037] The control unit 11 receives the corrected information, i.e., the correction information, from the correction unit 13, receives the rotational position of the motor 1 from the rotational position detector 14, and receives the detected current detected by the current detector 15, and uses the detected current and the current command generated based on the correction information and the rotational position to calculate the voltage command and output it to the inverter 9.

[0038] The inverter 9 applies a voltage to the motor 1 based on a voltage command. For example, the inverter 9 applies a voltage of a PWM waveform generated based on the voltage command to the motor 1 to drive the motor 1.

[0039] As a result, the control device 10 can control the voltage applied to the motor 1 so that the detected current detected by the current detector 15 follows the current command. Furthermore, the control device 10 changes the operation of the motor 1 to control the torque or rotation speed of the motor 1 and control the output of the motor 1.

[0040] Figure 2 FIG. 1 is a diagram showing the hardware structure of the control system in this embodiment. Figure 2 In the control system 100, the control device 10 includes a processor 90 and a storage device 91. The processor 90 executes a program stored in the storage device 91 to perform processing of the control device 10.

[0041] The processor 90 is constituted by a processor having a logical structure as a hardware circuit, such as a microcomputer, a DSP (Digital Signal Processor), or an FPGA.

[0042] Although not shown, the storage device 91 includes a volatile storage device such as a random access memory and a nonvolatile auxiliary storage device such as a flash memory. In addition, although not shown, the storage device 91 may also include a volatile storage device such as a random access memory and an auxiliary storage device such as a hard disk instead of the nonvolatile auxiliary storage device.

[0043] The processor 90 executes the program input from the storage device 91. Since the storage device 91 includes an auxiliary storage device and a volatile storage device, the program is input from the auxiliary storage device via the volatile storage device to the processor 90. In addition, the processor 90 can output data such as calculation results to the volatile storage device of the storage device 91, and can also store the above data in the auxiliary storage device via the volatile storage device.

[0044] Figure 1 The control unit 11, the calculation unit 12, and the correction unit 13 are implemented by the processor 90 executing the program stored in the storage device 91, or a processing circuit such as a system LSI not shown. In addition, the above functions may be performed by a plurality of processors 90 and a plurality of storage devices 91 in cooperation, or by a plurality of processing circuits in cooperation. In addition, the above functions may be performed by a combination of a plurality of processors 90 and a plurality of storage devices 91 and a plurality of processing circuits in cooperation.

[0045] Next, the operation of this embodiment will be described.

[0046] Figure 3 1 is a block diagram showing a part of the control device in the present embodiment. In the control device 10, the calculation unit 12 includes a temperature calculation unit 30, which estimates the temperature distribution of the motor 1 based on the thermal circuit model and outputs it as an estimated temperature T33 using the measured temperature T31 as one of the measurement information measured by the temperature sensor 31 as the sensor 8, the measured heat flux U32 as one of the measurement information measured by the heat flux sensor 32 as the sensor 8, and the correction information Cc output by the correction unit 13. The thermal circuit model is a model composed of a thermal circuit network including a thermal circuit using a thermal circuit equation established by Ohm's law.

[0047] In this embodiment, the measured temperature T31 indicates the measured temperature of the temperature sensor st2, and the measured heat flow U32 indicates the measured heat flow of the heat flux sensors sf1 and sf3. It should be noted that the measured temperature T31 and the measured heat flow U32 may also be multiple values ​​measured by multiple sensors 8, respectively.

[0048] The correction unit 13 includes a correction determination unit 34 that determines whether to correct the thermal circuit model, and a correction calculation unit 35 that outputs correction information Cc of a partial thermal circuit model that is a part of the thermal circuit model required for correction.

[0049] The correction determination unit 34 uses the estimated temperature T33 output by the temperature calculation unit 30 and the measured temperature T31 or the measured heat flow rate U32 to determine whether to make a correction, and outputs a correction instruction Dc if correction is necessary. Here, the temperature sensor 31 as the sensor 8 measures the temperature of the measurement position corresponding to the estimated temperature T33 as the measured temperature. In addition, the heat flux sensor 32 as the sensor 8 measures the heat flow rate at the measurement position corresponding to the estimated temperature T33 as the measured heat flow rate.

[0050] The correction calculation unit 35 uses the correction command Dc, the measured temperature T31, and the measured heat flow U32, that is, uses the measurement information of the temperature or heat flow corresponding to the measurement position measured by the sensor 8 in the motor 1, and corrects at least one of the thermal resistance, calorific value, and heat capacity corresponding to the measurement position based on the partial thermal circuit model, and outputs it as correction information Cc. Here, the partial thermal circuit model includes the measurement position where the sensor 8 performs measurement.

[0051] Furthermore, the correction unit 13 may correct at least any one of the thermal resistance, calorific value, and heat capacity corresponding to the measurement positions where the sensors 8 measure the measurement temperatures T31 using the measurement temperatures T31 measured by the sensors 8 provided in the motor 1 .

[0052] Next, use Figure 4 The thermal circuit model is explained.

[0053] Figure 4 : is a diagram showing a thermal circuit model of the entire motor used for temperature estimation by the control device in this embodiment. Figure 4 In FIG. 1 , the thermal circuit model 30 - 1 represents the heat flux and temperature of the entire space of the motor 1 by means of a thermal circuit, and has one or more nodes 20 , thermal resistances 21 , heat sources 22 , and heat capacitors 24 .

[0054] Node 20 indicates Figure 4 The node 20 b and the like include specific locations inside the motor 1 , and the temperature T of the location corresponding to each node 20 is allocated.

[0055] Thermal resistance 21 indicates the difficulty of heat flow and exists in Figure 4 The thermal resistances Rst1, Rst2, ..., Rro1, Rro2, ..., etc. of the motor 1 are all thermal circuits included in the motor 1. The corresponding heat flow U passes through each thermal resistance 21 respectively.

[0056] For the heat source 22, the following heat amount Q flows from the corresponding heat source 22, and the heat amount Q represents the heat amount Q flowing into the Figure 4The heat Qc1 caused by the copper loss generated by energizing the stator winding 5, the heat Qc2 caused by the copper loss generated by energizing the rotor winding 7, the inflow of heat from the outside of the motor 1, i.e., the heat flow Q3, Q4, and the heat Qst, Qr caused by the iron loss generated in the stator core 4 and the rotor core 6.

[0057] The heat capacitance 24 indicates the ease of temperature rise and is connected to the node 20. The thermal circuit model 30-1 is a combination of multiple nodes 20, multiple thermal resistors 21, multiple heat sources 22, and multiple heat capacitances 24. It is not limited to a two-dimensional model, and a three-dimensional connected model can also be constructed in the same way. In addition, in order to improve the estimation accuracy of the temperature, the node 20 can be further subdivided and connected to the thermal resistor 21, the heat source 22, and the heat capacitance 24.

[0058] exist Figure 4 In FIG. 1 , due to the axial symmetry of the central portion of the motor 1, only the minimum thermal circuit model is recorded, but in fact, the dotted line portion is also connected to the thermal circuit. In addition, Figure 4 The schematic diagram of the thermal circuit model 30-1 is shown, and each node 20, each thermal resistor 21, etc. are arranged in more detail. For a more detailed thermal circuit, use Figure 5 This will be described later. In the thermal circuit model 30-1, a temperature sensor ST2 is provided at the axial center of the stator core, and heat flux sensors SF1 and SF3 are provided near the stator winding 5 and the rotor winding 7. The temperature sensor ST2 measures the temperature at each measurement position, and the heat flux sensors SF1 and SF3 measure the heat flow at each measurement position. Here, the heat flux sensors SF1 and SF3 measure the heat flux at each measurement position, and the product of each measured heat flux and each measurement area of ​​the corresponding heat flux sensors SF1 and SF3 is taken as the measured heat flow and output.

[0059] Here, the measurement position of the sensor 8 is consistent with the position where the sensor 8 is installed. It should be noted that the measurement position and the installation position do not need to be consistent, and the sensor 8 can also be installed at a position away from the measurement position to measure the measurement information of the measurement position in a non-contact manner.

[0060] Next, use Figure 5 as well as Figure 6 A temperature estimation method of the calculation unit 12 using the thermal circuit model 30 - 1 is shown.

[0061] First, use Figure 5 The thermal circuit equation of the thermal circuit model 30 - 1 will be described. Figure 5 Yes means Figure 4 FIG. 3 is a diagram of a partial thermal circuit model 30 - 2 , which is a part of the thermal circuit model 30 - 1 .

[0062] Figure 5 Details include Figure 4 The thermal circuit model 30-1 includes the node 20a, the heat generation Qc1a of the heat source 22, and the value C1 of the heat capacitance 24. Figure 5 In the partial thermal circuit model 30-2, there are four nodes 20a1, 20a2, 20a3, 20a4, three thermal resistors 21a1, 21a2, 21a3, one heat source 22a, and two heat capacitors 24a1, 24a2. The three thermal resistors 21a1 and the four nodes 20a1, 20a2, 20a3, 20a4 are Figure 4 In the partial thermal circuit model 30-2, based on Ohm's law, equations (1), (2), and (3) hold true for thermal resistances R1, R2, and R3.

[0063]

[0064]

[0065]

[0066] In equations (1), (2), and (3), T1, T2, T3, and T4 are the temperatures corresponding to the four nodes 20a1, 20a2, 20a3, and 20a4, R1, R2, and R3 are the values ​​of the thermal resistances corresponding to the three thermal resistors 21, and U1, U2, and U3 are the heat fluxes corresponding to the three thermal resistors 21. Figure 5 The same equation is true for a part of the heat circuit equation that is established in the partial heat circuit model 30-2, and multiple parts of the same equation are established in the entire heat circuit model 30-1. Figure 4 The thermal circuit equation established in the thermal circuit model 30 - 1 of the entire motor 1 is shown as equation (4).

[0067]

[0068] The function F on the right side of the formula (4) is a matrix of functions representing the thermal circuit equation of the thermal circuit model 30-1, and R and Q are the value of the thermal resistance 21 and the heat generation of the heat source 22 contained in the thermal circuit equation, respectively. The left side of the formula (4) is a vertical vector with each of the estimated temperatures T33 as one term. The {T31, U32}T on the right side of the formula (4) is a vertical vector with each of the measured temperature T31 and the measured heat flow U32 as one term. Therefore, the formula (4) represents all the thermal circuit equations established in the thermal circuit model 30-1. Here, the "^" attached to T33, R and Q indicates that it is not a measured value but a pre-set estimated value, which is set as the estimated temperature, estimated resistance value, and estimated heat generation, respectively. The measured temperature T31 and the measured heat flow U32, which are the measurement information of the temperature sensor 31 and the heat flux sensor 32, are input into the formula (4), and the estimated temperature T33^ is calculated by solving the equation of the formula (4). Hereinafter, T33^ will be referred to as T33.

[0069] In equation (4), if the value R and the calorific value Q of the thermal resistance 21 in the thermal circuit model 30 are accurate with respect to the value R and the calorific value Q of the thermal resistance 21 of the motor 1, the temperature T33 can be accurately estimated. However, the value R and the calorific value Q of the thermal resistance 21 of the motor 1 change due to aging or the use of the motor 1. Therefore, it is assumed that an error occurs between the value R and the calorific value Q of the thermal resistance 21 of the motor 1 and the value R and the calorific value Q of the thermal resistance 21 in the thermal circuit model 30, and the estimated temperature T33 cannot be accurately estimated. Therefore, the value R and the calorific value Q of the thermal resistance 21 in the thermal circuit model 30 are set as the initial values ​​at the time of shipment, and the estimated resistance value R ^ and the estimated calorific value Q ^ are corrected by the correction unit 13 using the measurement information sent from the sensor 8 and a part of the thermal circuit equation. At this time, the estimated thermal resistance R ^ can be expressed as (the length of the heat flow path) ÷ (the cross-sectional area of ​​the heat flow path) ÷ (the thermal conductivity of the components of the motor 1) as the initial value.

[0070] When the heat source 22 is a winding, the cause of heat generation is copper loss, so the estimated heat generation Q ^ can be calculated using (resistance value of the winding) x (current value of the winding) ^2 as an initial value.

[0071] When the heat source 22 is the stator core 4 and the rotor core 6, the main component of the heat is the iron loss. In addition, the iron loss is proportional to the square of the magnitude of the magnetic flux density and the square of the frequency of the magnetic flux density. The induced voltage generated by the magnetic flux interlinking with the stator winding 5 is expressed by (magnetic flux density) × (cross-sectional area of ​​the magnetic path through which the magnetic flux passes) × (frequency of the magnetic flux density). Therefore, it can be considered that the iron loss is proportional to the square of the induced voltage of the stator winding 5. Therefore, the estimated heat generation Q^ of the stator core 4 and the rotor core 6 can be calculated by (the value of the induced voltage of the stator winding 5)^2×(proportional coefficient).

[0072] use Figure 6 A method of correcting the thermal resistance in the thermal circuit model 30 - 1 will be described.

[0073] Figure 6 This is a partial diagram of a thermal circuit model used when correcting thermal resistance in the control device according to the present embodiment. Figure 6 This is a partial thermal circuit model 30 - 2 a obtained by extracting a part of the thermal circuit model 30 - 1 . Figure 6 The partial heat circuit model 30-2a is, for example, extracted from Figure 5 The nodes 20a2, 20a4 and the thermal resistance R2 in the partial thermal circuit model 30-2a are partially constituted. In the partial thermal circuit model 30-2a, the temperature sensor 31 and the heat flux sensor 32 measure the temperatures T2, T4 and the heat flux U2 of the nodes 20a2, 20a4. The thermal resistance 21 has a thermal resistance value R2. The temperature sensor 31 and the heat flux sensor 32 can be set at any position of the motor 1, but are preferably located near the thermal resistance 21 to be corrected. The thermal circuit equation is based on Ohm's law, and the above equation (2) holds.

[0074] Here, U2 sets the heat flux flowing from the node 20a4 at the temperature T4 to the node 20a2 at the temperature T2 as positive. The correction unit 13 corrects the value of the thermal resistance R2, which is the value of the thermal resistance 21 between the nodes 20a4 and 20a2, based on the value obtained by solving the equation (2) using the temperatures T2, T4 and the heat flux U2 measured by the temperature sensor 31 and the heat flux sensor 32.

[0075] That is, the sensor 8 measures the temperatures of two different measurement positions in the motor 1, namely, the measurement position 20a4 and the measurement position 20a2, as the measurement temperature T4 and the measurement temperature T2, respectively, and measures the heat flow from the measurement position 20a4 to the measurement position 20a2 as the measurement heat flow U2. Next, the correction calculation unit 35 of the correction unit 13 corrects the thermal resistance R2 between the measurement position 20a4 and the measurement position 20a2 using the difference between the measurement temperature T4 and the measurement temperature T2 and the measurement heat flow U2.

[0076] Thus, if there is measurement information of two temperature sensors 31 and one heat flux sensor 32 located near the thermal resistor 21, the value of the thermal resistor R2 can be corrected at all times.

[0077] use Figure 7 A method of correcting the heat amount in the thermal circuit model 30 - 1 will be described.

[0078] Figure 7 This is a partial diagram of a thermal circuit model used when correcting the heating value in the control device of this embodiment. Figure 7This is a partial thermal circuit model 30 - 2 b obtained by extracting a part of the thermal circuit model 30 - 1 . Figure 7 The partial heat circuit model 30-2b is, for example, extracted from Figure 5 The thermal circuit is composed of three nodes 20a1, 20a2, and 20a4, two thermal resistors 21 having thermal resistance values ​​R1 and R2, respectively, and a heat source 22a. Temperatures T1, T2, and T4 are measured temperatures measured using a temperature sensor 31. The temperature sensor 31 can be set at any position, but is preferably located near the heat source 22a to be corrected. In this thermal circuit, equation (5) holds.

[0079]

[0080] Among them, U1 is a value that sets the direction of flow from node 20a1 at temperature T1 to node 20a4 at temperature T4 to a positive value, and U2 is a value that sets the direction of flow from node 20a4 at temperature T4 to node 20a2 at temperature T2 to a positive value. R1 is the value of thermal resistance 21 between nodes 20a1 and 20a4, and R2 is the value of thermal resistance 21 between nodes 20a4 and 20a2. Qc1a is the calorific value in the heat source 22a, and is a value that sets the direction of flow to node 20a4 at temperature T4 to a positive value. The correction unit 13 corrects the calorific value Qc1a based on the value obtained by solving equation (5) using the measured temperatures T1, T2, T4 and the known thermal resistance values ​​R1, R2. In the correction of the calorific value Qc1a, heat fluxes U1 and U2 may be used instead of using temperatures T1, T2, T4. In this case, the heat fluxes U1 and U2 are measured using a heat flux sensor 32.

[0081] That is, the sensor 8 measures the temperatures of the measurement positions 20a1, 20a4, and 20a2 of three different locations in the motor 1 as the measurement temperature T1, the measurement temperature T4, and the measurement temperature T2, respectively. The correction unit 13 corrects the heat amount Qc1a flowing into or out of the measurement position 20a4 using the measurement temperature T1, the measurement temperature T2, and the measurement temperature T4, the thermal resistance R2 between the measurement position 20a2 and the measurement position 20a4, and the thermal resistance R1 between the measurement position 20a4 and the measurement position 20a1.

[0082] Thus, if there is measurement information of two heat flux sensors 32 located near the heat source 22a, the heat value Qc1a can be corrected at all times.

[0083] In addition, the sensor 8 measures the heat flow at the first measurement position between the nodes 20a1 and 20a4 and the second measurement position between the nodes 20a4 and 20a2, which are two different measurement positions in the motor 1, as the measured heat flow U1, and measures the heat flow at the second measurement position as the measured heat flow U2. The correction unit 13 corrects the heat amount Qc1a flowing in or out between the first measurement position and the second measurement position using the difference between the measured heat flow U1 and the measured heat flow U2.

[0084] Thus, if there is measurement information of two heat flux sensors 32 located near the heat source 22a, the heat value Qc1a can be corrected at all times.

[0085] use Figure 8 The method of correcting the heat capacity in the thermal circuit model is described.

[0086] Figure 8 This is a partial diagram of a thermal circuit model used when correcting the heat capacity in the control device according to the present embodiment. Figure 8 This is a partial thermal circuit model 30 - 2 c obtained by extracting a part of the thermal circuit model 30 - 1 . Figure 8 The partial heat circuit model 30-2c is, for example, extracted from Figure 5 The heat circuit is composed of a node 20a1 and a heat capacity 24a1. There are four heat flow paths from the node 20a1, passing through heat fluxes U1, U4, U5, and U6 respectively. The temperature T1 of the node 20a1 is the measured temperature measured by the temperature sensor 31. In addition, the heat fluxes U1, U5, and U6 are the measured heat fluxes respectively measured by the heat flux sensor 32. In this heat circuit, equation (6) holds.

[0087]

[0088] Here, dT is the temperature rise per unit time of the node 20a1, and C1 is the value of the heat capacity of the heat capacity 24a1. The correction unit 13 corrects the heat capacity C1 based on the values ​​obtained by solving the equation (6) using the measured values ​​U1, U5, and U6 of the heat flux sensor 32.

[0089] That is, the sensor 8 measures the temperature rise per unit time of a measurement position of one part in the motor 1, namely, the measurement position 20a1, as the measured temperature rise dT, and measures three heat flows among the four heat flows U1, U4, U5, and U6 flowing in or out relative to the measurement position 20a1 as the measured heat flow U1, the measured heat flow U5, and the measured heat flow U6. When the heat flow among the four heat flows U1, U4, U5, and U6 that is different from the measured heat flow U1, the measured heat flow U5, and the measured heat flow U6 is set as the heat flow U4, the correction unit 13 uses the measured heat flow U1, the measured heat flow U5, the measured heat flow U6, and the measured temperature rise dT to correct the heat capacity C1 corresponding to the heat flow U4.

[0090] Thus, if there is measurement information of one temperature sensor 31 located near the heat capacitance 24a1 and measurement information of three heat flux sensors 32, the value C1 of the heat capacitance 24a1 can be corrected at all times.

[0091] It should be noted that the correction method for thermal resistance, calorific value and heat capacity is not limited to the correction method using the above-mentioned formula (2), formula (5) and formula (6). As long as the measurement information of the plurality of sensors 8 provided in the motor 1 and the correction information are used, Figure 4 A method for correcting at least a part of the thermal circuit equation established in the thermal circuit model 30-1 is sufficient.

[0092] By the above method, the correction unit 13 outputs information on correction of at least one of the thermal resistance, the calorific value, and the thermal capacity to the calculation unit 12 as the correction information Cc. Fig. 9 The specific steps of the correction method of the control device 10 are described with reference to the flowchart of FIG.

[0093] Fig. 9 This is a flowchart of control by the control device in this embodiment.

[0094] exist Fig. 9 In the initial value setting step S0, the temperature calculation unit 30 of the calculation unit 12 sets a predetermined initial value of at least one of the physical quantities of the thermal circuit model 30-1 used by the temperature calculation unit 30 of the calculation unit 12, namely, thermal resistance, calorific value, and heat capacity. Here, the initial value may be set, for example, when shipped from the factory, or the correction calculation unit 35 of the correction unit 13 may output the predetermined initial value as correction information Cc to the temperature calculation unit 30 for setting.

[0095] Then, in Fig. 9 In the measurement step S1, the temperature sensor 31 as the sensor 8 measures the measurement temperature T31, or the heat flux sensor 32 measures the measurement heat flux U32.

[0096] Then, in Fig. 9 In the temperature estimation step S2, the temperature calculation unit 30 of the calculation unit 12 estimates the estimated temperature T33 based on the thermal circuit model 30-1 using the measured temperature T31 and the measured heat flow U32. In addition, when the correction unit 13 outputs the correction information Cc, the temperature calculation unit 30 of the calculation unit 12 estimates the estimated temperature T33 based on the thermal circuit model 30-1 corrected using the correction information Cc.

[0097] Then, in Fig. 9 In the determination step S3, Figure 3 The correction judgment unit 34 of the correction unit 13 in the correction unit 13 compares the estimated temperature T33 estimated by the calculation unit 12 with the measured temperature T31 corresponding to the estimated temperature T33, and when the error ε between the estimated temperature T33 and the measured temperature T31 is greater than a preset threshold, an instruction for correction, i.e., a correction instruction Dc, is output as a correction trigger. When the error ε is less than the preset threshold, the process returns to the measurement step S1, and the temperature estimation step S2 and the judgment step S3 are repeated in this order until the error ε becomes greater than the preset threshold. It should be noted that the preset threshold is determined according to the accuracy required for the required temperature estimation. In addition, the correction judgment unit 34 is not limited to the stop of the motor 1, and the correction instruction Dc is also output when the motor 1 generates torque.

[0098] In the next Fig. 9 In the correction step S4, when the error ε is greater than a preset threshold value, the correction calculation unit 35 receives the correction instruction Dc, calculates the thermal resistance by equation (2), calculates the calorific value by equation (5), or calculates the thermal capacity by equation (6). Then, the correction calculation unit 35 outputs at least one of the calculated thermal resistance, calorific value, and thermal capacity to the calculation unit 12 as correction information Cc. The temperature calculation unit 30 of the calculation unit 12 uses the correction information Cc to correct at least one of the thermal resistance, calorific value, and thermal capacity of the thermal circuit model 30-1.

[0099] Next, the effects of this embodiment will be described.

[0100] As described above, the control device 10 includes: a calculation unit 12 that uses measurement information from the sensor 8 and the thermal circuit model 30-1 to estimate temperature; and a correction unit 13 that corrects at least one of the thermal resistance, calorific value, and heat capacity in the thermal circuit model 30-1.

[0101] At this time, it is assumed that the thermal resistance, calorific value, and thermal capacity are determined in the production process of the motor 1 at the time of writing the logic to the control device 10, and are not changed after leaving the factory. In the conventional control device for estimating the temperature, in the production process of the motor 1, if the same value is set for the thermal resistance, calorific value, and thermal capacity in the thermal circuit model for all products of the motor 1 regardless of the product, the error between the thermal resistance, calorific value, and thermal capacity of the motor 1 and the thermal resistance, calorific value, and thermal capacity in the thermal circuit model becomes larger due to the deviation of the thermal resistance, calorific value, and thermal capacity existing in each product of the motor 1. Therefore, it is assumed that the accuracy of the temperature estimation will be reduced.

[0102] Thermal resistance is expressed by (length of heat flow path) ÷ (cross-sectional area of ​​heat flow path) ÷ (thermal conductivity of components of motor 1). (Thermal conductivity of components of motor 1) is a physical property of components of motor 1 and is assumed to change due to aging.

[0103] In addition, the heat generation is expressed by (winding resistance value) × (winding current value) ^2 in the case of heat generation caused by copper loss of the winding of the motor 1, and by ((magnetic flux density) × (magnetic path cross-sectional area) × (frequency of magnetic flux density)) ^2 × (proportional coefficient) in the case of heat generation caused by iron loss of the rotor core 6 and the stator core 4. (Winding resistance value) and (magnetic flux density) are physical properties of the winding and the core, and are assumed to change due to aging.

[0104] In addition, heat capacity is expressed by (specific heat of component) x (mass). (Specific heat of component) is a physical property of the component and is assumed to change due to aging.

[0105] In the control device 10 of the present embodiment, when at least one of the thermal resistance, calorific value, and thermal capacity of the actual motor 1 changes due to aging, the correction unit 13 can correct the thermal resistance, calorific value, or thermal capacity in the thermal circuit model 30-1 corresponding to the change in at least one of the thermal resistance, calorific value, and thermal capacity of the actual motor 1. Therefore, the accuracy of temperature estimation can be improved compared to a conventional control device that estimates temperature.

[0106] In addition, the correction unit 13 performs correction when the error between the estimated temperature T33 estimated by the calculation unit 12 and the measured temperature corresponding to the estimated temperature T33 is greater than a preset threshold value. The threshold value is set in accordance with the required accuracy of temperature estimation, so that a certain accuracy of temperature estimation can be ensured. In addition, by changing the threshold value as needed, the accuracy of temperature estimation can be adjusted.

[0107] Furthermore, even when the same initial values ​​are set for the thermal resistance, calorific value, and thermal capacity in the thermal circuit model 30-1 in all products of the motor 1 at the time of shipment, the accuracy of temperature estimation can be improved by correcting the thermal resistance, calorific value, or thermal capacity in the thermal circuit model 30-1 in accordance with the deviation of the thermal resistance, calorific value, or thermal capacity of the actual machine of the motor 1 existing for each product. Furthermore, when the operation test of the motor 1 is performed before shipment, the control device 10 corrects the thermal resistance, calorific value, or thermal capacity, thereby correcting the initial value at the time of shipment for each product of the motor 1 to improve the accuracy of temperature estimation.

[0108] In addition, the correction unit 13 corrects the value R of the thermal resistor 21 by solving the equation (2) of the partial thermal circuit model 30-2a using the measured temperatures of the two temperature sensors 31. Thus, if there is only measurement information of the two temperature sensors 31 located near the thermal resistor 21, the correction unit 13 can calculate the correction information Cc for correcting the value R of the thermal resistor 21.

[0109] In addition, the correction unit 13 corrects the calorific value Q by solving the equation (5) of the partial heat circuit model 30-2b, 30-2c using the measured temperatures of the three temperature sensors. Thus, if there is only the measurement information of the three temperature sensors 31 located near the heat source 22, the correction unit 13 can calculate the correction information Cc for correcting the calorific value Q. In addition, even if two heat fluxes are measured, the correction unit 13 can calculate the correction information Cc for correcting the calorific value Q. Therefore, the correction unit 13 can calculate the correction information Cc for correcting the calorific value Q near the sensor 8 based on the measurement information of the two heat flux sensors 32.

[0110] In addition, the correction method of the thermal resistance value, the calorific value, and the heat capacity is not limited to the above method, as long as the method uses the measurement information of the sensor 8 to solve the equation of the partial thermal circuit model including the sensor 8. Therefore, the equation used for correction is not limited to equation (2), equation (5), and equation (6), but may be an equation representing any thermal circuit model.

[0111] In addition, the sensor 8 used for correction only needs to measure the temperature or heat flow required to solve the equation of the partial thermal circuit model used in the correction. Therefore, the sensor 8 can also be any combination of the temperature sensor 31 and the heat flux sensor 32. For example, in the case of correcting the calorific value, the measurement information used in the formula (5) can be a combination of (T1, T4, T2) and (U1, U2) in addition to the combination of (T1, T4, U2). Thus, any thermal resistance, calorific value or heat capacity can be corrected by changing the type and measurement position of the sensor 8.

[0112] In addition, as described above, the correction of thermal resistance, calorific value or heat capacity is not limited to when the motor 1 is stopped, and the correction is also performed during the period when the motor 1 generates torque. In the motor 1, during the period when the torque is generated, the temperature of the entire motor 1 rises and the thermal conductivity changes. Therefore, the value of thermal resistance represented by (length of heat flow path) ÷ (cross-sectional area of ​​heat flow path) ÷ (thermal conductivity of components of the motor 1) changes.

[0113] In addition, during the period of generating torque, the overall temperature of the motor 1 rises due to the winding current flowing in the stator winding 5, and for example, the value of the resistance of the stator winding 5, that is, the winding resistance value changes. Therefore, the heat generation of the stator winding 5 represented by (winding resistance value)×(winding current value)^2 also changes.

[0114] In addition, since heat capacity also has temperature dependence, heat capacity also changes in accordance with temperature changes. Therefore, when the temperature of the entire motor 1 rises during the period of generating torque, the accuracy of estimating the temperature of the motor 1 decreases.

[0115] Even in the case assumed as described above, by correcting the thermal resistance, calorific value, or heat capacity while the motor 1 is generating torque, it is possible to improve the accuracy of temperature estimation when the temperature of the motor 1 rises.

[0116] Implementation method 2.

[0117] Fig.10 This is a flowchart for implementing control of the control device in Embodiment 2 of the invention according to the present application. Fig.11 This is a diagram showing the output of the motor with respect to time in the control device according to the present embodiment. Fig.12 : is a diagram showing estimated temperatures with respect to time in the control device according to the present embodiment. Fig.13 This is a diagram showing the output of the motor with respect to time in the control device according to the present embodiment. Fig.14 : is a graph showing estimated temperature with respect to time in the control device of this embodiment. Fig.10 , Fig.11 , Fig.12 , Fig.13 as well as Fig.14 The control device 10a in this embodiment is different from the control device 10 in Embodiment 1 in the following points.

[0118] exist Fig.10 After the temperature estimation step S2 is performed in the control step S5, the temperature is estimated according to the temperature of the Fig. 9In the same temperature estimation step S2, the controller 11 estimates the estimated temperature T33 of the motor 1 as in the first embodiment, and sends a control command to the inverter 9 to change the output of the motor 1. Then, in the control step S5, the controller 11 controls the output of the motor 1, and then changes the output of the motor 1 to the estimated temperature T33 of the motor 1 estimated by the calculation unit 12. Fig. 9 In the same determination step S3, as in the first embodiment, the correction determination unit 34 of the correction unit 13 compares the estimated temperature T33 estimated by the calculation unit 12 with the measured temperature T31 corresponding to the estimated temperature T33, and outputs a correction instruction Dc as a correction trigger when the error ε between the estimated temperature T33 and the measured temperature T31 is greater than a preset threshold. When the error ε is less than the preset threshold, the process returns to the measurement step S1, and the temperature estimation step S2 and the determination step S3 are repeated in this order until the error ε becomes greater than the preset threshold. The processing after the correction step S4 is the same as in the first embodiment.

[0119] Next, the control of the output of the electric motor 1 in the control step S5 will be described.

[0120] exist Fig.11 In FIG. 1 , the horizontal axis represents time t, and the vertical axis represents the output of the motor 1. Fig.12 In FIG. 1 , the horizontal axis represents time t, and the vertical axis represents the estimated temperature T33 of the motor 1. Fig.11 as well as Fig.12 As shown, when the estimated temperature T33 exceeds the preset threshold value Tth at time t1, the control unit 11 reduces or stops the output of the motor 1 so that the estimated temperature T33 decreases. This control can reduce the estimated temperature T33 to below the threshold value Tth.

[0121] In addition, Fig.13 In FIG. 1 , the horizontal axis represents time t, and the vertical axis represents the output of the motor 1. Fig.14 In FIG. 1 , the horizontal axis represents time t, and the vertical axis represents the estimated temperature T33 of the motor 1. Fig.13 as well as Fig.14 As shown, the control unit 11 may limit the output of the motor 1 to be equal to or less than Plim and operate the motor 1 within a range equal to or less than Plim so as to maintain the estimated temperature T33 equal to or less than the threshold value Tth.

[0122] Next, the effects of this embodiment will be described.

[0123] The control device 10 of the motor system 100 of the present embodiment includes a control unit 11 that changes the operation of the motor 1 according to the estimated temperature T33 estimated by the calculation unit 12. That is, the control unit 11 controls the voltage applied to the motor 1 by the inverter 9 according to the estimated temperature. Thus, when the estimated temperature T33 is high, the overheat protection of the motor 1 can be performed by controlling to reduce or stop the output of the motor 1 so that the temperature corresponding to the estimated temperature T33 does not rise above the threshold value Tth. In addition, the output of the motor 1 is limited in a manner to maintain the estimated temperature T33 within the vicinity of the threshold value Tth, and the motor 1 is operated within this range, so that the estimated temperature T33 can be suppressed within the threshold value Tth and the output of the motor 1 can be maximized.

[0124] In addition, when the motor 1 generates torque, the control unit 11 controls the voltage applied to the motor 1 by the inverter 9 according to the estimated temperature T33 to control the output of the motor 1. Thus, as in the first embodiment, during the period when the torque is generated in the motor 1, by correcting the thermal resistance, calorific value, or heat capacity, the accuracy of the temperature estimation when the temperature of the motor 1 rises can be improved.

[0125] Description of Reference Numerals

[0126] 1 motor (rotating electric machine), 2 stator, 3 rotor, 4 stator core, 5 stator winding, 6 rotor core, 7 rotor winding, 8 sensor, 9 inverter (power converter), 10, 10a control device, 11 control unit, 12 calculation unit, 13 correction unit, 14 rotation position detector, 15 current detector, 20, 20a, 20b, 20c, 20d, 20e, 20f, 20g node, 21 thermal resistance, 22, 22a heat source, 23 axis, 24, 24a1, 24a2 heat capacity, 30 temperature calculation unit, 30-1 thermal circuit model, 30-2, 30-2a, 30-2b, 30-2c partial thermal circuit model, 31, st2 temperature sensor, 32, sf1, sf3 heat flux sensor, 34 correction judgment unit, 35 correction calculation unit, 90 processor, 91 storage device, 100 control system (motor system).

Claims

1. A control device, wherein: The control device includes a correction unit that corrects at least one of thermal resistance, calorific value, and heat capacity as physical quantities representing a thermal circuit model, the thermal circuit model including a thermal circuit of the rotating electrical machine. The correction unit corrects at least one of the thermal resistance, the calorific value, and the heat capacity corresponding to the measurement position using measurement information including a temperature or a heat flow rate corresponding to the measurement position measured by a sensor unit in the rotating electrical machine. The sensor unit measures temperatures of two different measurement positions in the rotating electrical machine, namely, a first measurement position and a second measurement position, as first measurement temperatures and second measurement temperatures, respectively, and measures the heat flow from the first measurement position to the second measurement position as a first measurement heat flow, The correction unit corrects the thermal resistance between the first measurement position and the second measurement position using a difference between the first measurement temperature and the second measurement temperature and the first measured heat flow rate.

2. A control device, wherein: The control device includes a correction unit that corrects at least one of thermal resistance, calorific value, and heat capacity as physical quantities representing a thermal circuit model, the thermal circuit model including a thermal circuit of the rotating electrical machine. The correction unit corrects at least one of the thermal resistance, the calorific value, and the heat capacity corresponding to the measurement position using measurement information including a temperature or a heat flow rate corresponding to the measurement position measured by a sensor unit in the rotating electrical machine. The sensor unit measures the heat flow at the first measurement position as a first measurement heat flow and measures the heat flow at the second measurement position as a second measurement heat flow, among the measurement positions at two different locations in the rotating electrical machine, namely, a first measurement position and a second measurement position. The correction unit corrects the heat amount flowing in or out between the first measurement position and the second measurement position using a difference between the first measured heat flow rate and the second measured heat flow rate.

3. A control device, wherein: The control device includes a correction unit that corrects at least one of thermal resistance, calorific value, and heat capacity as physical quantities representing a thermal circuit model, the thermal circuit model including a thermal circuit of the rotating electrical machine. The correction unit corrects at least one of the thermal resistance, the calorific value, and the heat capacity corresponding to the measurement position using measurement information including a temperature or a heat flow rate corresponding to the measurement position measured by a sensor unit in the rotating electrical machine. The sensor unit measures the temperatures of the three different measurement positions in the rotating electrical machine, namely, a first measurement position, a second measurement position, and a third measurement position as a first measurement temperature, a second measurement temperature, and a third measurement temperature, respectively. The correction unit corrects the heat amount flowing into or out of the second measurement position using the first measurement temperature, the second measurement temperature, and the third measurement temperature, a first thermal resistance between the first measurement position and the second measurement position, and a second thermal resistance between the second measurement position and the third measurement position.

4. A control device, wherein: The control device includes a correction unit that corrects at least one of thermal resistance, calorific value, and heat capacity as physical quantities representing a thermal circuit model, the thermal circuit model including a thermal circuit of the rotating electrical machine. The correction unit corrects at least one of the thermal resistance, the calorific value, and the heat capacity corresponding to the measurement position using measurement information including a temperature or a heat flow rate corresponding to the measurement position measured by a sensor unit in the rotating electrical machine. The sensor unit measures a temperature rise per unit time at a first measurement position, which is one of the measurement positions in the rotating electrical machine, as a measured temperature rise, and measures three of the four heat flows flowing into or out of the first measurement position as a first measured heat flow, a second measured heat flow, and a third measured heat flow, When the heat flow rate different from the first measured heat flow rate, the second measured heat flow rate, and the third measured heat flow rate among the four heat flow rates is set as the first heat flow rate, The correction unit corrects the heat capacity corresponding to the first heat flow rate using the first measured heat flow rate, the second measured heat flow rate, the third measured heat flow rate, and the measured temperature rise.

5. The control device according to any one of claims 1 to 4, wherein: The correction unit corrects at least any one of the thermal resistance, the calorific value, and the heat capacity corresponding to the measurement position by using the thermal circuit model including the measurement position and the measurement information.

6. The control device according to any one of claims 1 to 4, wherein: The control device further includes a calculation unit that estimates the temperature of the rotating electrical machine as an estimated temperature using the thermal circuit model. the sensor unit measures the temperature of the measurement position corresponding to the estimated temperature as the measurement temperature, The correction unit corrects at least one of the thermal resistance, the calorific value, and the heat capacity corresponding to the measurement position when an absolute value of a difference between the estimated temperature and the measured temperature is equal to or larger than a predetermined threshold value.

7. The control device according to claim 6, wherein: The control device further includes a control unit configured to control the rotating electrical machine using the thermal circuit model. The control unit controls a voltage applied to the rotating electric machine through the power converter according to the estimated temperature.

8. The control device according to claim 6, wherein: The control device further includes a control unit configured to control the rotating electrical machine using the thermal circuit model. The control unit controls the output of the rotating electric machine by controlling a voltage applied to the rotating electric machine through a power converter according to the estimated temperature when the rotating electric machine generates torque.

9. A control system, wherein: The control system comprises: The control device according to any one of claims 1 to 8; and The sensor portion.

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