Rotating electric machine control device

Abstract

A control device for a rotating electrical machine includes a rotor, a stator having a stator core and a winding, and a thermistor that detects the temperature of the winding by a portion to be measured, which is a temperature measurement site for measuring the temperature of the winding. The control device includes a first temperature estimation unit that estimates the temperature of the winding, and a second temperature estimation unit that estimates the temperature of the winding. And a first temperature estimation unit that calculates an estimated temperature of a first portion that is a part of the winding, the first temperature estimation unit acquiring a first difference, and calculating a temperature correction value of the first portion on the basis of the acquired first difference, calculating the estimated temperature of the first site on the basis of the calculated temperature correction value of the first site and the temperature detected by the measurement target unit, the first difference indicating the temperature difference between the temperature of the first site and the temperature detected by the measurement target unit; the temperature of the first part is calculated according to the rotating speed of the rotor and the current value input and output to the rotating motor.

Description

TECHNICAL FIELD

[0001] The present application relates to a control device of a rotary electric machine. BACKGROUND

[0002] A water-cooled electric machine has a structure in which heat of a winding is transferred to cooling water flowing in a frame via a stator core and a frame, but the temperature of the winding of a coil end portion away from a cooling source is in a high state. On the other hand, in order to increase maximum torque, the amount of a magnet is increased in the electric machine, and when a large current is passed, the leakage magnetic flux in a slot of the stator core becomes large, and thus the eddy current loss of the winding in the slot increases in addition to the copper loss due to the passage of the current, and the temperature becomes the highest.

[0003] In this case, if the winding temperature in the slot is to be measured in the case where a temperature sensor provided for the purpose of protecting the electric machine from overheating is provided at the coil end portion, the winding temperature in the slot is higher than the winding temperature of the coil end portion, and thus the actual temperature and the measured temperature deviate. Therefore, it is necessary to correct the error of the measured temperature.

[0004] Patent Document 1 below discloses a coil temperature estimation device of a rotary electric machine, which has: a heat discharge amount calculation section that calculates a heat discharge amount from a coil using a temperature of a refrigerant that cools the stator and a thermal resistance of at least a portion between the refrigerant and the coil; a heat generation amount calculation section that calculates a heat generation amount generated by a loss of the coil; and a coil temperature calculation section that calculates a temperature of an axial central portion of a slot coil portion using the heat discharge amount from the coil and the heat generation amount generated by the loss of the coil.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-100323 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In view of the technology of Patent Document 1, an object of the present application is to provide a control device of a rotary electric machine that achieves appropriate temperature protection of the rotary electric machine using one thermistor.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] A control device of a rotary electric machine has a rotor, a stator having a stator core and a winding, a thermistor that detects a temperature of the winding by being disposed at a measured portion that is a temperature measurement site of the winding, the control device of the rotary electric machine having a first temperature estimation portion that calculates an estimated temperature of a first portion that is a part of the winding, the first temperature estimation portion acquiring a first difference that indicates a temperature difference between the temperature of the first portion in an arbitrary operation state of the rotary electric machine and the temperature of the measured portion (thermistor) detected at the measured portion, calculating a temperature correction value of the first portion based on the acquired first difference, calculating the estimated temperature of the measured portion (thermistor) based on the calculated temperature correction value of the first portion and the temperature of the measured portion (thermistor) detected at the measured portion.

[0012] Effects of the Invention

[0013] According to the present application, it is possible to provide a control device of a rotary electric machine that achieves appropriate temperature protection of the rotary electric machine using one thermistor. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a configuration view of a vehicle that mounts the control device of the rotary electric machine of the present application.

[0015] Figure 2 is a sectional view that explains the configuration of the rotary electric machine of one embodiment of the present application.

[0016] Figure 3 is an explanatory view of the stator that explains the disposition site of the thermistor of one embodiment of the present application.

[0017] Figure 4 is a functional block diagram of the control device of the rotary electric machine of one embodiment of the present application.

[0018] Figure 5 is a characteristic diagram that indicates the difference between the measured temperature and the actual measured temperature of one embodiment of the present application. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present application will be explained with reference to the drawings. The following description and drawings are provided to explain the present application by way of example, and appropriate omissions and simplifications are made for the sake of clarity. The present application can also be embodied in other various ways. Each component can be singular or plural unless specifically limited otherwise.

[0020] The position, size, shape, range, etc. of each component shown in the drawings are sometimes not actual position, size, shape, range, etc. in order to easily understand the present application. Therefore, the present application is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0021] (One embodiment and overall configuration)

[0022] ( Figure 1 )

[0023] The vehicle 1 has a motor 2, a motor control device 3, a control system 4, a communication line 5, an ECU 6, and a battery pack 7. The motor control device 3 performs control of the motor 2. The control system 4 is configured of the motor 2 and the motor control device 3. The motor control device 3, the ECU 6, and the battery pack 7 are communicatively connected to each other via the communication line 5.

[0024] ( Figure 2 )

[0025] Figure 2 is a schematic view showing the overall configuration of the motor 2 of one embodiment of the present application. In Figure 2 , the inside of the motor 2 is shown by taking a part of the motor 2 as a cross section.

[0026] As shown in Figure 2 , the motor 2 includes a housing 10, a stator 20 having a stator core 21 fixed to the housing 10, and a rotor 30 rotatably disposed inside the stator 20. The frame of the motor 2 is formed of a front bracket 11, the housing 10, a rear bracket 12, and a junction box 13, and the housing 10 has a water passage 15 for cooling water of the motor together with a water jacket 14.

[0027] The rotor 30 is fixed to a shaft 31 supported by a bearing 30A of the front bracket 11 and a bearing 30B of the rear bracket 12, and is rotatably held inside the stator core 21.

[0028] The stator core 21 is fixed to the housing 10 by shrink fitting or the like, and the stator 20 is indirectly cooled by the cooling water in the water passage 15 via the housing 10.

[0029] In a slot portion of the stator core 21, a winding 22 is disposed across a sheet-shaped insulator formed of an insulating resin material.

[0030] The winding 22 is fixed to the stator core 21 across the insulator, with varnish applied thereto during manufacture.

[0031] The winding 22 is formed by inserting a substantially U-shaped copper flat conductor into a slot of the stator core 21 from the axial direction, bending the open side end portion of the flat conductor, and electrically connecting the bent portions of the flat conductors to each other by welding or the like. The coil end portion 23 is a portion where the stator winding is concentrated across the slots, protruding from both ends of the stator core 21.

[0032] The winding 22 is a three-phase Y-connected winding, and a U-phase stator winding, a V-phase stator winding, and a W-phase stator winding are formed by the winding 22 of flat conductors. One end of each phase winding is arranged as a neutral point of a neutral line connecting the U-phase / V-phase / W-phase at the coil end portion 23, and the other end forms an output line.

[0033] The output line receives electric power for connection to the outside of the rotating electric machine, and a wiring portion 24 is arranged from the coil end portion 23, and is connected to a machine control device 3 such as an inverter or the like outside via an output terminal.

[0034] When the machine 2 operates and electric current flows through the winding 22, the winding 22 generates copper loss and generates heat. The coil end portion 23 is dense with the winding 22, and heat due to the copper loss is concentrated, and the temperature becomes high.

[0035] The coil end portion 23 is cooled by heat transfer through the housing 10, the stator core 21, and the insulator by cooling water flowing through the water passage 15 of the housing 10.

[0036] For temperature detection of the winding 22, a thermistor 25 is attached to the winding 22. The thermistor 25 is a temperature sensor having a temperature detecting element composed of a semiconductor whose resistance value greatly changes with temperature. In the machine control device 3 and the control system 4 Figure 1 ), the temperature of the winding 22 is detected by monitoring the resistance value of the thermistor 25.

[0037] In the case where the detected temperature of the winding 22 exceeds a prescribed value, there is concern that the life of the insulating coating of the winding and the varnish applied to the stator will be affected, and therefore the machine control device 3 limits or stops the performance of the machine 2 to prevent abnormal overheating of the winding 22.

[0038] Therefore, the thermistor 25 is preferably arranged at a portion of the winding 22 where the temperature is highest, but the portion where the temperature is highest changes due to structural problems and operating conditions, and therefore the portion where the thermistor 25 is arranged does not necessarily become the portion where the temperature is highest.

[0039] Figure 3

[0040] Figure 3 is a schematic view showing the configuration of the stator 20 of one embodiment of the present application. The stator 20 has a stator core 21, a winding 22, and a thermistor 25 that detects the temperature of the winding 22. The thermistor 25 detects the temperature of the winding 22 by being arranged at a measured portion 26 that is a temperature measurement portion in the winding 22.

[0041] A plurality of windings 22 are inserted into the stator core 21. The winding 22 is inserted from one side of the stator core 21, and both end portions thereof protrude to the outside in the axial direction as coil end portions 23. ​​

[0042] In the stator core 21, a connection portion 24 is provided on one side where the output lines of the U phase / V phase / W phase are configured. A thermistor 25 is provided near the connection portion 24. The thermistor 25 is provided on the measurement portion 26. The measurement portion 26 may also be provided not on a part of the winding 22, but on a part of the busbar connected to the winding 22, thereby enabling the measurement of not only the temperature of the winding 22, but also the temperature of the busbar.

[0043] When the motor 2 is not rotating, a three-phase unbalanced current flows through the U-phase / V-phase / W-phase, increasing the likelihood that the temperature rise of a specific phase's winding 22 will increase. That is, the accuracy of the temperature estimation of the winding 22 (described later) deteriorates depending on whether the phase with the higher temperature is used as the measurement section 26 or the phase with the lower temperature. Therefore, the measurement section 26 is provided in the portion of the wiring section 24 that forms the neutral point of the winding 22. This way, even when the motor 2 is in a three-phase unbalanced energizing state, it is less susceptible to thermal imbalance and reaches a balance point, thus improving the accuracy of the temperature estimation of the winding 22.

[0044] ( Figure 4 )

[0045] The motor control device 3 has a first table 41 and a second table 42 for storing temperature difference constants, a first temperature estimation unit 43, a second temperature estimation unit 44, a maximum value selection unit 45, and a motor control unit 3a.

[0046] First, the control for calculating the estimated temperature value of the basic in-slot winding 22 of the present invention will be explained using the first table 41 and the first temperature estimation unit 43. The motor control device 3 acquires data from the motor 2 ( Figure 2 The rotor speed and the indicated current output by motor 2 are input to the first meter 41. Alternatively, the indicated current can be the current value detected by motor control device 3.

[0047] The first table 41 is related to the temperature measurement of the first part, i.e., the portion of the winding 22 in the slot of the stator 20. The first table 41 stores a temperature difference mapping at temperature equilibrium, which will be measured in the measuring section 26 ( Figure 3 The difference between the detected temperature and the temperature of the first part in any state corresponds to the indicated current and rotor speed of motor 2. Table 41 calculates the thermistor 25 based on this temperature difference mapping, which has a temperature difference constant. Figure 3 The difference between the temperature of the measured part 26 and the temperature of the first part in any state. This calculated difference is set as the first difference 41a.

[0048] The first temperature estimation section 43 acquires the temperature detected at the measured section 26 (thermistor temperature) from the thermistor 25, and acquires the first difference 41a from the first table 41. The first temperature estimation section 43 calculates a temperature correction value that corrects the measured temperature value of the measured section 26 detected at the measured section 26 (thermistor temperature) based on the acquired first difference 41a and the temperature information detected at the measured section 26.

[0049] The first temperature estimation section 43 calculates the estimated temperature value 43a of the first section based on the calculated temperature correction value and the measured temperature value of the measured section 26 (thermistor temperature). By outputting the estimated temperature value 43a thus calculated to the motor control section 3a, the portion of the winding 22 at which the highest temperature is attained can be grasped and controlled, and thus appropriate temperature protection of the motor 2 can be achieved.

[0050] In addition, as shown in Figure 4 the present application further has, as functional blocks, a second table 42, a second temperature estimation section 44, and a maximum value selection section 45 in addition to the first table 41 and the first temperature estimation section 43, and thus the accuracy of temperature estimation can be further improved. Hereinafter, the motor control device 3 having the first table 41 and the first temperature estimation section 43, the second table 42 and the second temperature estimation section 44, and the maximum value selection section 45 will be described. In addition, the description of the calculation of the estimated temperature value 43a of the first section of the winding 22 using the first table 41 and the first temperature estimation section 43 will be omitted below because it is the same as described above.

[0051] The motor control device 3 acquires the rotational speed of the rotor from the motor 2 and the command current output to the motor 2, and inputs them to the second table 42. In addition, the command current can also be the current value detected by the motor control device 3. The second table 42 is related to the temperature measurement of the portion of the winding 22 of the coil end portion 23 of the stator 20, i.e., the second section. The second table 42 stores a temperature difference map at the time of temperature balance that maps the difference between the temperature detected at the measured section 26 and the temperature of the second section in an arbitrary state with the command current to the motor 2 and the rotational speed of the rotor.

[0052] The second table 42 calculates the difference between the temperature of the measured section 26 detected by the thermistor 25 (thermistor temperature) and the temperature of the second section in an arbitrary state based on the temperature difference map. This difference is set as a second difference 42a.

[0053] The second temperature estimation section 44 acquires the temperature detected by the temperature detection section 26 (thermistor temperature) from the thermistor 25, and acquires the second difference 42a from the second table 42. The second temperature estimation section 44 calculates a temperature correction value that corrects the measured temperature value detected by the temperature detection section 26 (thermistor temperature) based on the acquired second difference 42a and the temperature information detected by the temperature detection section 26. The second temperature estimation section 44 calculates the estimated temperature value 44a of the second portion based on the calculated temperature correction value and the measured temperature value of the temperature detection section 26.

[0054] The maximum value selection section 45 is a selection section that selects the estimated temperature value, acquires the estimated temperature value 43a of the first portion and the estimated temperature value 44a of the second portion, and outputs the larger one of the estimated temperature value 43a and the estimated temperature value 44a to the motor control section 3a.

[0055] Thus, even in a case where the portion that becomes the highest temperature of the winding 22 differs depending on the operating point of the motor 2, it is possible to map and store the temperature difference in advance in the motor control device 3 based on the rotational speed of the rotor and the command current to the motor 2, and thus it is possible to correspond to an arbitrary temperature difference that differs depending on the amount of heat generation (loss), and to select the maximum temperature within a range that does not exceed the heat resistance temperature of the motor 2 in order to control in such a manner that the output is limited when an arbitrary temperature is exceeded, and it is possible to achieve stable coil temperature estimation that does not diverge due to accumulation of errors. Thus, it is possible to achieve appropriate temperature protection of the motor 2. In addition, it is not necessary to take an excessive safety rate for temperature protection of the motor 2 compared to the past, and it is possible to increase the temperature protection start temperature to the limit of the constituent components of the motor 2.

[0056] In addition, the estimation of the highest temperature does not need to be limited to the portion of the winding 22, and for example, in a case where the terminal block, which is not illustrated, is the highest temperature, it is also possible to estimate the temperature of the terminal block.

[0057] In addition, the motor control device 3 can acquire information of the temperature of the refrigerant (water temperature) supplied to the motor 2 in addition to the rotational speed of the rotor and the command current, and input to the first table 41 and the second table 42 to calculate the temperature correction value, and in this case, the first difference 41a and the second difference 42a are calculated in correspondence with the command current, the rotational speed of the rotor, and the temperature of the refrigerant. Thus, even in a case where the temperature of the constituent components differs depending on the water temperature at the same operating point, and the amount of heat generation changes, it is possible to improve the accuracy of the temperature estimation value of the winding 22 by changing the temperature difference constant for estimation depending on the water temperature.

[0058] ( Figure 5 )

[0059] The temperatures associated with winding 22 differ at the slot, at the coil ends, at the busbar, and as detected by the thermistor 25. For example... Figure 5 As shown, the temperature difference between the two parts of the motor 2 when the motor 2 is in a temperature equilibrium state is caused by the difference in their respective heat generation, heat dissipation, thermal resistance, and heat capacity, exhibiting a roughly one-time delay characteristic.

[0060] like Figure 4 As shown, the first temperature estimation unit 43 and the second temperature estimation unit 44 can calculate the temperature correction value required for calculating the temperature estimation value of the winding 22, for example, using the following mathematical formula 1, as the temperature correction value Tdelta(n) at time n. Furthermore, let the first difference 41a or the second difference 42a at time n be ΔTsteady(n), and the constant be τc.

[0061] [Formula 1]

[0062]

[0063] The above formula is a difference equation that adds the difference between the correction value (target value) and the correction value Δt seconds ago to the correction value Δt seconds ago. Therefore, no temperature error accumulation occurs, and the value will not exceed the target value input into the temperature difference mapping (the estimated temperature value does not diverge). Furthermore, the temperature can be estimated even during short-term (transitional) conditions.

[0064] According to the embodiments of the present invention described above, the following effects are achieved.

[0065] (1) The control device 3 of the rotary electric machine 2 includes: a rotor, a stator 20 having a stator core 21 and windings, and a thermistor 25 that detects the temperature of the windings 22 by means of a measuring part 26 disposed as a temperature measuring section for measuring the temperature of the windings 22. The control device 3 of the rotary electric machine 2 includes: a first temperature estimation part 43 that calculates an estimated temperature of a first part that is part of the windings 22; the first temperature estimation part 43 acquires a first difference 41a; calculates a temperature correction value for the first part based on the acquired first difference 41a; and calculates an estimated temperature 16a of the first part based on the calculated temperature correction value of the first part and the temperature (thermistor) detected by the measuring part 26. The first difference 41a represents the temperature difference between the temperature of the first part and the temperature detected by the measuring part 26 in any operating state based on the rotor speed and the current value input to and output to the rotary electric machine 2. Thus, a control device for a rotary electric machine 2 that achieves appropriate temperature protection using a thermistor 25 can be provided.

[0066] (2) A first table 41 is provided, which stores a mapping between the first difference 41a and the temperature difference corresponding to the current value and the rotor speed. The first difference 41a is calculated based on the temperature difference mapping, and the first temperature estimation unit 43 obtains the first difference 41a from the first table 41. As a result, the temperature of the winding 22 in the part where the thermistor 25 is not provided can be estimated.

[0067] (3) When the first temperature estimation unit 43 sets the first difference 41a at time n to ΔTsteady(n) and the constant to τc, it calculates the temperature correction value Tdelta(n) at time n using the above formula 1. As a result, the temperature estimation value of the winding 22 does not diverge.

[0068] (4) The stator 20 has a connection portion that connects to the winding 22, and the measurement portion 26 is provided on the portion of the connection portion 24 that forms the neutral point of the winding 22. As a result, the estimation accuracy is improved even when three-phase unbalanced current is applied.

[0069] (5) Table 41 calculates the first difference 41a in correspondence with the indicated current, the rotor speed, and the temperature of the refrigerant supplied to the rotating motor 2. As a result, the estimation accuracy of the temperature of the winding 22 is improved.

[0070] (6) It includes: a second temperature estimation unit 44 that calculates the estimated temperature 17a of a second part of the winding 22 that differs from the first part; and a temperature selection unit 18 that selects the higher of the estimated temperature 16a of the first part and the estimated temperature 17a of the second part. The second temperature estimation unit 44 acquires a second difference 42a, calculates a temperature correction value for the second part based on the acquired second difference 42a, and calculates the estimated temperature 17a of the second part based on the calculated temperature correction value of the second part and the temperature (thermistor) detected by the measuring unit 26. The second difference 42a represents the temperature difference between the temperature of the second part of the winding in any operating state based on the rotor speed and the current value and the temperature of the winding 22 detected by the measuring unit 26. Thus, appropriate temperature protection of the motor 2 can be achieved.

[0071] (7) The first part is a portion of the winding 22 disposed in the slot of the stator 20 on the stator core 32, and the second part is a portion of the coil end 23 of the winding 22 protruding outward from the stator core 21 in the axial direction. Thus, the maximum temperature of the winding 22 can be estimated.

[0072] Furthermore, the present invention is not limited to the embodiments described above, and various modifications and other configurations can be combined without departing from its spirit. Additionally, the present invention is not limited to the structure having all the configurations described in the above embodiments, but also includes structures in which a portion of the configuration has been removed.

[0073] Explanation of symbols

[0074] 1: Vehicle, 2: Motor, 3: Motor control device, 3a: Motor control unit, 4: Control system, 5: Communication line, 6: ECU, 7: Battery pack, 10: Housing, 11: Front bracket, 12: Rear bracket, 13: Junction box, 14: Water jacket, 15: Water passage, 20: Stator, 21: Stator core, 22: Winding, 23: Coil end, 24: Wiring part, 25: Thermistor, 26: Measured part, 30: Rotor, 30A: Bearing, 30B: Bearing, 31: Shaft, 41: First meter, 41a: First differential, 42: Second meter, 42a: Second differential, 43: First temperature estimation part, 43a: Estimated temperature of the first part, 44: Second temperature estimation part, 44a: Estimated temperature of the second part, 45: Maximum value selection part.

Claims

1. A control device for a rotating electric machine, comprising: a rotor, a stator having a stator core and windings, and a thermistor for detecting the temperature of the windings by means of a measuring portion disposed at a temperature measuring section serving as a temperature measuring point for measuring the temperature of the windings, characterized in that the control device for the rotating electric machine includes: The first temperature estimation unit calculates the estimated temperature of a first portion that is part of the winding. The first temperature estimation unit acquires a first difference, calculates a temperature correction value for the first part based on the acquired first difference, and calculates an estimated temperature for the first part based on the calculated temperature correction value for the first part and the temperature detected by the measuring unit. The first difference represents the temperature difference between the temperature of the first part and the temperature detected by the measuring unit. The temperature of the first part is calculated based on the rotational speed of the rotor and the current value input and output to the rotating motor.

2. The control device for a rotating electric motor according to claim 1, characterized in that, The system has a first table that stores a temperature difference mapping, which maps the first difference to the current value and the rotor speed. The first difference is calculated based on the temperature difference mapping. The first temperature estimation unit obtains the first difference from the first table.

3. The control device for a rotating electric motor according to claim 1, characterized in that, When the first temperature estimation unit sets the first difference at time n as ΔTsteady(n) and the constant as τc, it calculates the temperature correction value Tdelta(n) at time n using the following formula. 。 4. The control device for a rotating electric motor according to claim 1, characterized in that, The stator has a wiring portion that connects to the winding. The part to be measured is located on the portion of the wiring section that forms the neutral point of the winding.

5. The control device for a rotating electric motor according to claim 2, characterized in that, The first table calculates the first difference in correspondence with the indicated current, the rotational speed of the rotor, and the temperature of the refrigerant supplied to the rotating motor.

6. The control device for a rotating electric motor according to claim 1, characterized in that, It has a second temperature estimation unit that calculates an estimated temperature for a second portion of the winding that differs from the first portion; and a temperature selection unit that selects the higher of the estimated temperature of the first portion and the estimated temperature of the second portion. The second temperature estimation unit acquires a second difference, calculates a temperature correction value for the second part based on the acquired second difference, and calculates the estimated temperature of the second part based on the calculated temperature correction value of the second part and the temperature detected by the measuring unit. The second difference represents the temperature difference between the temperature of the second part of the winding and the temperature of the winding detected by the measuring unit. The temperature of the second part of the winding is calculated based on the rotor speed and the current value.

7. The control device for a rotating electric motor according to claim 6, characterized in that, The first part is a portion of the winding disposed in the slot of the stator on the stator core. The second part is a portion of the coil end of the winding that protrudes axially outward from the stator core.

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