Motor control device

Abstract

A motor control device (40) is provided with a drive circuit (41) and a control unit (50). The drive circuit (41) has a drive element that switches energization to the motor (10). The control unit (50) has: a drive state acquisition unit (53) that acquires the drive state of the motor (10); a reference temperature calculation unit (581) that calculates, as a reference temperature, the peripheral temperature of the drive element on the basis of the value detected by the temperature sensor (45); and a temperature estimation unit (582) that estimates an element temperature, which is the temperature of the drive element. The temperature estimation unit (582) estimates a rising temperature on the basis of the driving state of the motor (10) and the reference temperature when it is determined that motor driving is performed, and estimates a falling temperature on the basis of the reference temperature when it is determined that motor driving is not performed. The temperature estimation unit (582) updates the estimated value of the element temperature on the basis of the rising temperature or the falling temperature.

Description

Cross-reference of related applications

[0001] This application is based on Japanese Patent Application No. 2023-064013, filed on April 11, 2023, the contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to motor control devices. Background Technology

[0003] Previously, control devices for gear shifting mechanisms that use a motor as a drive source to switch gears were known. For example, in Patent Document 1, an operation count counter was used to count the number of times the gear shifting operation was performed continuously at short operation intervals of less than a predetermined time. When the count value reached a predetermined value, the control was switched from normal control to heat suppression control, and power to the motor was temporarily prohibited.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 4999395 Summary of the Invention

[0005] However, temperature detection was not performed in Patent Document 1. Therefore, in order to work even in high-temperature environments, a strict upper limit on the number of gear shifts needs to be set, reducing the number of possible shifts compared to the original limit. Furthermore, the temperature of the drive element is sometimes difficult to directly detect when considering its mounting configuration. The object of this disclosure is to provide a motor control device that can appropriately estimate the temperature of the drive element.

[0006] The motor control device disclosed herein includes a drive circuit and a control unit. The drive circuit has a drive element that switches the energization to the motor. The control unit includes: a drive state acquisition unit that acquires the drive state of the motor; a reference temperature calculation unit that calculates the ambient temperature of the drive element as a reference temperature based on the detection value of a temperature sensor; and a temperature estimation unit that estimates the temperature of the drive element, i.e., the element temperature.

[0007] When the temperature estimation unit determines that motor drive is in operation, it estimates the rising temperature based on the motor's drive state and a reference temperature. When it determines that motor drive is not in operation, it estimates the falling temperature based on the reference temperature. The temperature estimation unit updates the estimated component temperature based on the rising or falling temperature. Therefore, the temperature of the drive component can be appropriately estimated. Attached Figure Description

[0008] The foregoing and other objects, features, and advantages of this disclosure will become more apparent from the accompanying drawings and from the detailed description below. The drawings are as follows.

[0009] Figure 1This is a schematic diagram illustrating one embodiment of a drive-by-wire shifting system.

[0010] Figure 2 This is a block diagram illustrating the control unit of one embodiment.

[0011] Figure 3 This is a flowchart illustrating the temperature estimation process of one embodiment.

[0012] Figure 4 This is a timing diagram illustrating the initial value setting of the estimated element temperature in one embodiment.

[0013] Figure 5 This is an explanatory diagram illustrating the sum of values ​​in one embodiment.

[0014] Figure 6 This is an explanatory diagram illustrating the subtraction value of one embodiment.

[0015] Figure 7 This is an explanatory diagram illustrating the subtraction value of one embodiment.

[0016] Figure 8 This is a flowchart illustrating the reference temperature setting process of one embodiment.

[0017] Figure 9 This is a flowchart illustrating the heat generation determination process of one embodiment. Detailed Implementation

[0018] (One implementation method) The motor control device of this disclosure will now be described with reference to the accompanying drawings. Figures 1-9 This describes a motor control device according to one embodiment. For example... Figure 1 As shown, the ECU 40, which serves as a motor control device, is applied, for example, to the shift-by-wire system 1. The shift-by-wire system 1 includes a motor 10, a detent mechanism 20, a parking lock mechanism 30, and the ECU 40, etc.

[0019] Motor 10, for example, is a switched reluctance motor, which rotates by being powered by a battery installed in a vehicle (not shown), and functions as the drive source for the stop mechanism 20. Motor 10 is equipped with a rotation angle sensor, such as an encoder, to detect the rotational position.

[0020] The rotation of motor 10 is output to output shaft 15 via a reducer (not shown). Thus, the rotation of motor 10 is transmitted to stop mechanism 20. An output shaft sensor 16 for detecting the angle of output shaft 15 is provided on output shaft 15.

[0021] The stop mechanism 20 includes a stop plate 21, a stop spring 25, and a stop roller 26, which transmit the rotational driving force output from the reducer to the manual valve 28 and the parking lock mechanism 30.

[0022] The stop plate 21 is fixed to the output shaft 15 and driven by the motor 10. Four valleys 22 are formed on the stop plate 21 side of the stop spring 25, corresponding to the gear positions P (park), R (reverse), N (neutral), and D (drive).

[0023] A pin 24 protruding parallel to the output shaft 15 is provided on the stop plate 21. The pin 24 is connected to the manual valve 28. The stop plate 21 is driven by the motor 10, thereby causing the manual valve 28 to reciprocate axially. That is, the stop mechanism 20 converts the rotational motion of the motor 10 into linear motion and transmits it to the manual valve 28. The manual valve 28 is located on the valve body 29. By reciprocating axially with the manual valve 28, the hydraulic supply path to the hydraulic clutch (not shown) is switched, the engagement state of the hydraulic clutch is switched, thereby changing the gear position.

[0024] The stop spring 25 is a plate-shaped component capable of elastic deformation, with a stop roller 26 at its front end. The stop spring 25 applies force to the stop roller 26 towards the rotation center of the stop plate 21. When a predetermined or greater rotational force is applied to the stop plate 21, the stop spring 25 elastically deforms, and the stop roller 26 moves between the valleys 22. By the stop roller 26 being embedded in one of the valleys 22, the swing of the stop plate 21 is restricted, the axial position of the manual valve 28 and the state of the parking lock mechanism 30 are determined, and the gear shift position is fixed.

[0025] The parking locking mechanism 30 includes a parking lever 31, a cone 32, a parking lock lever 33, a shaft 34, and a parking gear 35. The parking lever 31 is generally L-shaped, with one end 311 fixed to the stop plate 21. A cone 32 is provided at the other end 312 of the parking lever 31. The cone 32 is formed such that its diameter decreases as it approaches the other end 312.

[0026] The parking lock lever 33 abuts against the conical surface of the cone 32 and is configured to swing about the shaft 34. A protrusion 331, capable of engaging with the parking gear 35, is provided on the parking lock lever 33 side. When the cone 32 moves in the P direction due to the rotation of the stop plate 21, the parking lock lever 33 is pushed upwards, and the protrusion 331 engages with the parking gear 35. Conversely, when the cone 32 moves in a non-P (NotP) direction, the engagement of the protrusion 331 with the parking gear 35 is disengaged.

[0027] The parking gear 35 is mounted on an axle (not shown) and is configured to engage with the protrusion 331 of the parking lock lever 33. When the parking gear 35 engages with the protrusion 331, the rotation of the axle is restricted. When the gear is in a position other than P (Not P), the parking gear 35 is not locked by the parking lock lever 33, and the rotation of the axle is not hindered by the parking lock mechanism 30. However, when the gear is in P, the parking gear 35 is locked by the parking lock lever 33, and the rotation of the axle is restricted.

[0028] The ECU 40 includes a drive circuit 41, a thermistor 45, and a control unit 50. The drive circuit 41 has a drive element (not shown), and the energization of the motor windings is switched by switching the drive element. The thermistor 45 is mounted on the same substrate as the drive element and detects the substrate temperature as the ambient temperature of the drive element.

[0029] The control unit 50 is mainly composed of a microcomputer or the like, and internally includes a CPU, ROM, RAM, I / O, and buses connecting these components (not shown). The processing in the control unit 50 can be software processing performed by the CPU executing programs pre-stored in a physical memory device such as ROM (i.e., a non-temporary tangible recording medium that can be read), or it can be hardware processing based on dedicated electronic circuits.

[0030] The control unit 50 includes a drive control unit 51, a voltage detection unit 52, a motor drive status acquisition unit 53, an ECU status determination unit 54, a fault determination unit 55, and a heat generation determination and processing unit 58. The drive control unit 51 controls the drive of the motor 10 by controlling the on / off operation of the drive elements of the drive circuit 41. The voltage detection unit 52 detects the applied voltage V applied to the drive circuit 41. In this embodiment, the battery voltage detected by a voltage sensor (not shown) is set as the applied voltage V.

[0031] The motor drive status acquisition unit 53 acquires the drive status of the motor 10. The drive status of the motor 10 includes whether the motor 10 is driven or not; if the motor is driven, it includes information related to the drive mode and the gear position before and after the shift. The ECU status determination unit 54 determines the start-up status of the ECU 40. Furthermore, after the termination determination of the ECU 40, the control unit 50 can perform various processes such as termination processing during the termination processing execution time. The fault determination unit 55 detects a fault in the thermistor 45.

[0032] like Figure 2 As shown, the heat generation determination processing unit 58 includes a reference temperature calculation unit 581, a temperature estimation unit 582, and a heat generation determination unit 583. The reference temperature calculation unit 581 calculates the reference temperature Tb based on the detection value of the thermistor 45. In this embodiment, the reference temperature Tb is the substrate temperature. The calculation of the reference temperature Tb will be explained later.

[0033] The temperature estimation unit 582 estimates the temperature of the drive element based on the reference temperature Tb, the fault determination of the thermistor 45, and the driving state of the motor 10. Hereinafter, the estimated value of the drive element temperature is set as the estimated element temperature Tm. The heat generation determination unit 583 determines the heat generation of the drive element based on the estimated element temperature Tm.

[0034] However, in the online gear shifting system 1, the temperature of the motor 10 and drive components may rise when the driver frequently performs unnecessary gear shifting operations. For example, to suppress the temperature rise, the number of consecutive operations with short intervals is counted, and the system switches from normal control to heat suppression control (e.g., motor energization is disabled) when the count value reaches a predetermined value. However, if the heat suppression control is switched to based on the count value without temperature detection, the number of shifts needs to be strictly set to ensure that it works even in high-temperature environments, reducing the number of possible shifts compared to the originally possible number.

[0035] Furthermore, if the heat generated by the drive element is more severe than that of the motor 10, it is possible to anticipate the heat generated by the drive element and further limit the number of switching operations. However, from an installation perspective, it is difficult to measure the temperature of the drive element itself. Therefore, in this embodiment, the temperature of the drive element is estimated based on the reference temperature Tb, and heat generation is determined based on the estimated element temperature Tm. This allows for setting an appropriate number of switching operations, increasing the number of operations compared to switching to heat suppression control using a count value.

[0036] based on Figure 3 The flowchart below describes the temperature estimation process of this embodiment. This process is performed by the control unit 50 at predetermined cycles. Hereinafter, the "steps" such as step S101 will be omitted and abbreviated as the symbol "S".

[0037] In S101, the control unit 50 determines whether it is the start-up time of ECU 40. If it is determined that it is not the start-up time of ECU 40 (S101: No), the process proceeds to S104. If it is determined that it is the start-up time of ECU 40 (S101: Yes), the process proceeds to S102, and the termination element temperature Tm_f and termination reference temperature Tb_f written in S105 are read.

[0038] In S103, the heat determination processing unit 58 sets the initial value Tm_i of the element temperature. Based on Figure 4 This explains the setting of the initial value Tm_i. Figure 4In this case, the horizontal axis is set as time and the vertical axis is set as temperature. However, the time scale does not necessarily match the actual situation. Additionally, the reference temperature Tb is represented by a solid line, and the estimated component temperature Tm is represented by a single-dot dash line. The reference temperature at the time of disconnecting the power supply of the ECU 40 is set as the reference temperature at termination Tb_f, the reference temperature at the time of turning on the power supply is set as the reference temperature at startup Tb_w, and the value obtained by subtracting the reference temperature at startup Tb_w from the reference temperature at termination Tb_f is set as the reference temperature decrease amount ΔTb (refer to Equation (1)).

[0039] ΔTb = Tb_f - Tb_w ……(1) When the power supply of the ECU 40 is disconnected at time x11 and turned on at time x12, if the reference temperature decrease amount ΔTb is greater than the temperature decrease determination threshold Tb_th, the time elapsed since the previous power disconnection is sufficient to cool the drive component, and the probability that the estimated component temperature Tm that has risen due to power-on has dropped to the same level as the reference temperature Tb is high. Therefore, the initial value Tm_i of the component temperature is set as the reference temperature at startup Tb_w.

[0040] When the power supply of the ECU 40 is disconnected at time x13 and turned on at time x14, if the reference temperature decrease amount ΔTb is below the temperature decrease determination threshold Tb_th, not much time has elapsed since the previous power disconnection, and the probability that the estimated component temperature Tm that has risen due to power-on has not dropped to the reference temperature Tb is high. Therefore, the initial value Tm_i of the component temperature is set as the component temperature at termination Tm_f.

[0041] When the power supply of the ECU 40 is disconnected at time x15 and turned on at time x16, if the reference temperature at startup Tb_w is higher than the reference temperature at termination Tb_f due to an increase in the external air temperature or the like, the higher value between the component temperature at termination Tm_f and the reference temperature at startup Tb_w is set as the initial value Tm_i of the component temperature. In this example, since Tm_f < Tb_w, the initial value Tm_i of the component temperature is set as the reference temperature at startup Tb_w.

[0042] Return Figure 3 In S104, which is transferred to when a negative determination is made in S101, the control unit 50 determines whether it is the termination time of the ECU 40. If it is determined that it is the termination time of the ECU 40 (S104: Yes), it transfers to S105, sets the current component temperature as the component temperature at termination Tm_f, and writes the reference temperature as the reference temperature at termination Tb_f into the temperature storage unit 59 which is a non-volatile memory. If it is determined that it is not the termination time of the ECU 40 (S104: No), it transfers to S106.

[0043] In S106, the heat determination processing unit 58 determines whether the motor 10 has been driven. If it is determined that the motor 10 has not been driven (S106: No), the process proceeds to S108. If it is determined that the motor 10 has been driven (S106: Yes), the process proceeds to S107.

[0044] In S107, the heat determination processing unit 58 reads the sum value AD, adds the sum value AD to the previous value of the estimated element temperature Tm, and uses it as the current value of the estimated element temperature Tm (refer to formula (2)). The subscript (n) represents the current value, and (n-1) represents the previous value.

[0045] The sum value AD is a value set based on the temperature rise of the drive element during a single drive of motor 10, such as a gear shift. For example... Figure 5 As shown, the sum value AD is calculated using the applied voltage V, the temperature deviation ΔT obtained by subtracting the reference temperature Tb from the estimated element temperature Tm (refer to equation (3)), and the driving state of the motor 10 as independent variables. Figure 5 The mapping is one example, and the threshold value can be set appropriately. Figure 6 and Figure 7 The same applies.

[0046] Tm （n） =Tm （n-1） +AD ……(2) ΔT=Tm-Tb ……(3) When the applied voltage V is less than the voltage threshold Vth, the upper mapping segment is used, setting the sum of values ​​AD=UPWL1 for wall-hitting drive and AD=UPCP1 for switching drive. When the applied voltage V is greater than the voltage threshold Vth, the lower mapping segment is used, setting the sum of values ​​AD=UPWL2 for wall-hitting drive and AD=UPCP2 for switching drive. When the applied voltage V is large, the estimated component temperature Tm is more likely to rise, therefore UPWL2 is relatively larger than UPWL1, and UPCP2 is relatively larger than UPCP1.

[0047] The magnitude relationship of the thresholds a, b, and c related to the temperature deviation ΔT is a < b < c. That is, when ΔT < a, the difference between the estimated component temperature Tm and the reference temperature Tb is relatively small, and when ΔT ≥ c, the difference between the estimated component temperature Tm and the reference temperature Tb is relatively large. For example, when the applied voltage V < Vth and the driving state of the motor 10 is hitting the wall, the added value AD = UPWL1_1 is the largest when ΔT < a, followed by UPWL1_2 and UPWL1_3, and the value UPWL1_4 when ΔT ≥ c is the smallest. That is, when the ambient temperature is lower than the driving component temperature, it is difficult for the driving component to heat up due to energization, so the added value AD is relatively reduced. The same applies when the applied voltage V ≥ Vth and in cases other than hitting-the-wall driving.

[0048] The driving state of the motor 10 includes hitting-the-wall driving and switching driving for each gear position. In hitting-the-wall driving, the stopper roller 26 is moved to the driving limit on the P side or the D side, and learning is performed with the wall position as the reference position. In hitting-the-wall driving, torque suppression control is performed to suppress the impact when the stopper roller 26 abuts against the wall, so the heat generation amount is larger than that in normal gear position switching driving. Therefore, if the applied voltage V and the temperature deviation ΔT are the same, the added value AD = UPLW during hitting-the-wall driving is relatively larger than the added value AD = UPCP during switching.

[0049] In the switching driving for each gear position, an added value corresponding to the gear position switching angle is set. For example, the switching angle during P-D switching is larger than that during other gear position switchings, and the energization time is longer, so the added value during P-D switching makes the added value AD relatively larger compared to other gear position switchings. Additionally, for example, when the R-N switching angle is equal to the N-D switching angle, the values can be equal, such as UPCP1_5 = UPCP1_9. Furthermore, since the larger the switching angle, the longer the switching time, it can also be understood that the added value AD is set according to the gear position switching time. Additionally, instead of the mapping operation, the added value AD can be determined by mathematical formula operations using the gear position switching angle, gear position switching time, etc.

[0050] Return Figure 3 , in S108 where a negative determination is made in S106 and the process transfers, the heat generation determination processing unit 58 determines whether the elapsed time Xstop from the stop of driving the motor 10 is less than the first stop determination time Xth1. When it is determined that the elapsed time Xstop from the stop of driving is less than the first stop determination time Xth1 (S108: Yes), the process transfers to S109. In S109, the heat generation determination processing unit 58 reads the subtracted value SU1, and subtracts the subtracted value SU1 from the previous value of the estimated component temperature Tm to obtain the current value of the estimated component temperature Tm (Equation (4)).

[0051] When it is determined that the elapsed time Xstop since the drive stop of the slave motor 10 is equal to or longer than the first stop determination time Xth1 (S108: No), the process proceeds to S110. In S110, the heat generation determination processing unit 58 determines whether the elapsed time Xstop since the drive stop of the slave motor 10 is less than the second stop determination time Xth2. The second stop determination time Xth2 is set to a value larger than the first stop determination time Xth1. When it is determined that the elapsed time Xstop since the drive stop is equal to or longer than the first stop determination time Xth1 and less than the second stop determination time Xth2 (S110: Yes), the process proceeds to S111. In S111, the heat generation determination processing unit 58 reads the phase subtraction value SU2, and subtracts the phase subtraction value SU2 from the previous value of the estimated element temperature Tm to obtain the current value of the estimated element temperature Tm (Equation (5)). When it is determined that the elapsed time Xstop since the drive stop is equal to or longer than the second stop determination time Xth2 (S110: No), the process proceeds to S112, and the estimated element temperature Tm is set to the reference temperature Tb.

[0052] Tm （n） =Tm （n-1） -SU1 …… (4) Tm （n） =Tm （n-1） -SU2 …… (5) The phase subtraction values SU1 and SU2 are values set according to the elapsed time Xstop since the drive stop of the slave motor 10. Immediately after the drive stop of the slave motor 10, the rate of decrease in the estimated element temperature per unit time Xi (for example, 0.5 [s]) is relatively large, and the rate of decrease becomes smaller as time elapses since the drive stop. Therefore, in the present embodiment, according to the elapsed time Xstop since the drive stop of the slave motor 10, it is set such that the smaller the elapsed time Xstop since the drive stop, the larger the phase subtraction value. That is, when the temperature deviation ΔT is equal, SU1 > SU2. Here, the phase subtraction value SU is set in two stages, but it may be set in three or more stages, or the phase subtraction value SU may be determined by mathematical formula operations using the elapsed time Xstop.

[0053] Figure 6 represents the phase subtraction value SU1, Figure 7 represents the phase subtraction value SU2. The magnitude relationship of the thresholds d, e, f, and g related to the temperature deviation ΔT is d < e < f < g. That is, when ΔT < d, the difference between the estimated element temperature Tm and the reference temperature Tb is relatively small, and when ΔT ≥ g, the difference between the estimated element temperature Tm and the reference temperature Tb is relatively large.

[0054] As Figure 6As shown, when ΔT < d, the subtraction value SU1 is set to 0. In addition, in ascending order are DWN1_1, DWN1_2, DWN1_3, and the value DWN1_4 when ΔT ≥ g is the largest. As Figure 7 shown, when ΔT < d, the subtraction value SU2 is set to 0. In addition, in ascending order are DWN2_1, DWN2_2, DWN2_3, and the value DWN2_4 when ΔT ≥ g is the largest. That is, when the ambient temperature is lower than the temperature of the drive element, the temperature is likely to decrease in the non-powered state, so the subtraction value SU is made relatively large.

[0055] Based on Figure 8 the flowchart of is used to explain the reference temperature setting process. In S201, the reference temperature calculation unit 581 obtains the detection value from the thermistor 45. In S202, the reference temperature calculation unit 581 determines whether the detection value of the thermistor 45 is normal. If it is determined that the detection value of the thermistor 45 is normal (S202: Yes), the process proceeds to S203. If it is determined that the detection value of the thermistor 45 is abnormal (S202: No), the process proceeds to S204.

[0056] In S203, the reference temperature calculation unit 581 calculates the reference temperature Tb based on the detection value of the thermistor 45. When the thermistor 45 includes multiple (for example, two) detection elements, the average value is set as the reference temperature Tb. Additionally, an operation value other than the average value or a representative value can also be set as the reference temperature Tb.

[0057] In S204, the reference temperature calculation unit 581 does not use the detection value of the thermistor 45 and sets the reference temperature Tb to a predetermined value. In this embodiment, the highest temperature Tb_max (for example, 90°C) detected when the thermistor 45 is normal is set as the reference temperature Tb. Thus, even when the thermistor 45 fails, the temperature of the drive element can be estimated. Additionally, assuming the worst-case scenario, by setting the reference temperature Tb to the highest temperature Tb_max, thermal damage to the drive element can be prevented. The set reference temperature Tb is used for the calculation of estimating the element temperature Tm.

[0058] Based on Figure 9The flowchart illustrates the heat generation determination process. In S301, the heat generation determination unit 583 determines whether the estimated element temperature Tm is higher than the protection temperature Tg. The protection temperature Tg is set based on the temperature at which thermal damage to the drive element occurs, to prevent thermal damage to the drive element. It then determines whether the estimated element temperature Tm is higher than the protection temperature Tg. If it is determined that the estimated element temperature Tm is higher than the protection temperature Tg (S301: Yes), the process proceeds to S302, and the heat generation determination flag Flg_h is set to ON. If it is determined that the estimated element temperature Tm is lower than the protection temperature Tg (S301: No), the process proceeds to S303, and the heat generation determination flag Flg_h is set to OFF.

[0059] The overheating determination flag Flg_h is sent to the drive control unit 51. In the drive control unit 51, gear shifting is performed under normal control when the overheating determination flag Flg_h is off, and overheating suppression control is implemented when the overheating determination flag Flg_h is on. In this embodiment, gear shifting is prohibited as overheating suppression control.

[0060] As described above, the ECU 40 includes a drive circuit 41 and a control unit 50. The drive circuit 41 has a drive element that switches the power supply to the motor 10. The control unit 50 includes a motor drive state acquisition unit 53 that acquires the drive state of the motor 10, a reference temperature calculation unit 581 that calculates the ambient temperature of the drive element as a reference temperature Tb based on the detection value of the thermistor 45, and a temperature estimation unit 582 that estimates the temperature of the drive element, i.e., the element temperature.

[0061] When the temperature estimation unit 582 determines that a motor drive is in progress, it estimates the rising temperature based on the motor's driving state and a reference temperature Tb. When it determines that no motor drive is in progress, it estimates the falling temperature based on the reference temperature Tb. The temperature estimation unit 582 updates the estimated value of the component temperature, i.e., the estimated component temperature Tm, based on an addition value AD or a subtraction value SU. Specifically, the estimated component temperature Tm is calculated by adding the addition value AD or subtracting the subtraction value SU.

[0062] Therefore, the temperature of the drive components can be appropriately estimated. For example, when the ECU 40 is applied to the shift-by-wire system 1, compared to setting the upper limit of the number of gear shifts in a short period of time by assuming the worst-case scenario without estimating the component temperature, the number of shifts that can be performed in the normally used temperature range can be increased.

[0063] The summation value AD used in estimating the component temperature when a motor drive is in operation is based on the temperature deviation ΔT, which is the difference between the estimated component temperature Tm and the reference temperature Tb. Here, the estimated component temperature Tm used in the calculation of the summation value AD is a previous value or an initial value; it can also be understood as using the summation value AD to calculate the current value of the estimated component temperature Tm. In this embodiment, the summation value AD is the value for each drive of the intermittently driven motor 10, and in the wired shifting system 1, it is the value for each gear shift or each collision. Therefore, the estimated component temperature Tm during motor drive can be calculated relatively simply without using current detection values, etc.

[0064] The control unit 50 includes a voltage detection unit 52 that detects the applied voltage applied to the drive circuit 41. The sum value AD is estimated based on the applied voltage V. As a result, the estimated element temperature Tm during motor drive can be calculated more appropriately.

[0065] The driving state of motor 10 includes gear shift angle or gear shift time. The sum value AD is estimated based on the gear shift angle or gear shift time in this gear shift. Additionally, the driving state of motor 10 includes gear shift drive and wall-collision drive. The sum value AD is estimated based on whether the driving state of motor 10 is gear shift drive or wall-collision drive. Therefore, the temperature of the drive element in the drive-by-wire system 1 can be estimated with high accuracy, thus increasing the number of shifts.

[0066] The subtraction value SU used in estimating the component temperature when it is determined that no motor drive has been implemented is based on the difference between the estimated component temperature Tm and the reference temperature Tb. Here, the estimated component temperature Tm used in the calculation of the subtraction value SU is a previous value or an initial value; it can also be understood that the current value of the estimated component temperature Tm is calculated using the subtraction value SU. Furthermore, the subtraction value SU is estimated based on the elapsed time Xstop from the termination of motor 10's drive, with a larger subtraction value SU the shorter the elapsed time Xstop. Therefore, the estimated component temperature Tm when no motor drive has been implemented can be calculated appropriately.

[0067] The control unit 50 includes a fault determination unit 55 for determining a fault in the thermistor 45. In the event of a fault in the thermistor 45, the temperature estimation unit 582 sets a reference temperature Tb to a predetermined value. In this embodiment, the predetermined value is set based on worst-case conditions, specifically the maximum temperature Tb_max. Therefore, even in the event of a fault in the thermistor 45, gear switching can continue while preventing thermal damage to the drive element.

[0068] Motor 10 is an actuator related to gear shifting. Gear shifting is prohibited when the estimated element temperature Tm is higher than the protection temperature Tg. This prevents thermal damage to the drive element.

[0069] The control unit 50 has a temperature storage unit 59, which stores the component temperature Tm_f when the power supply to the ECU 40 is disconnected, i.e., the termination component temperature, and the reference temperature Tb_f when the power supply is disconnected, i.e., the termination reference temperature.

[0070] When the temperature drop of the reference temperature during the period after the power to the ECU 40 is disconnected and then reconnected is greater than a determination threshold (i.e., the reference temperature drop ΔTb > Tb_th), the temperature estimation unit 582 sets the initial value Tm_i of the component temperature at the time of power-on to the reference temperature at the time of power-on, i.e., the start-up reference temperature Tb_w. Conversely, when the temperature drop of the reference temperature during the period after the power to the ECU 40 is disconnected and then reconnected is less than or equal to the determination threshold (i.e., 0 ≤ ΔTb ≤ Tb_th), the temperature estimation unit 582 sets the initial value Tm_i of the component temperature at the time of power-on to the termination component temperature Tm_f.

[0071] Furthermore, since the component temperature will not fall below the reference temperature, if the reference temperature Tb_w at startup is higher than the component temperature Tm_f at termination, the temperature estimation unit 582 sets the initial value Tm_i of the component temperature at power-on to the reference temperature Tb_w at startup. Therefore, the initial value Tm_i of the component temperature at power-on can be appropriately set, and the estimated component temperature Tm can be appropriately calculated.

[0072] Alternatively, the initial value of the component temperature Tm_i at power-on can be set to the component temperature Tm_f at termination, independent of the reference temperature drop ΔTb. This prevents thermal damage even if the ECU 40 is immediately restarted.

[0073] In this implementation, ECU 40 corresponds to "motor control device", thermistor 45 corresponds to "temperature sensor", and motor drive status acquisition unit 53 corresponds to "drive status acquisition unit". Additionally, the sum value AD corresponds to "rising temperature", the subtraction value SU corresponds to "falling temperature", the temperature decrease determination threshold Tb_th corresponds to "determination threshold (related to the determination of the amount of temperature decrease)", the protection temperature Tg corresponds to "high temperature determination threshold", and the wall collision drive corresponds to "reference position learning drive".

[0074] (Other implementation methods) In the above embodiment, an SR motor is exemplified as the motor. In other embodiments, the motor may be a motor other than an SR motor, such as a brushless DC motor. In the above embodiment, the temperature sensor is a thermistor. In other embodiments, the temperature sensor may be a sensor other than a thermistor. Furthermore, in the above embodiment, the temperature sensor and the drive element are mounted on the same substrate. In other embodiments, as long as the ambient temperature of the drive element can be detected, the temperature sensor may be located in a location other than the same mounting substrate as the drive element. Additionally, temperature information used in other devices can be acquired through communication or the like.

[0075] In the above embodiment, the stop plate has four valleys corresponding to each gear position. In other embodiments, the number of valleys on the stop plate is not limited to four, and can be any number of two or more. Furthermore, the configuration and arrangement of the stop mechanism and parking lock mechanism can differ from the above embodiment.

[0076] In the above embodiments, the motor control device is applied to a shift-by-wire system involved in gear shifting. In other embodiments, the motor control device can also be applied to vehicle-mounted devices other than shift-by-wire systems. Additionally, it can be applied to devices outside of vehicles.

[0077] The disclosure of "the motor is an actuator related to gear shifting, the driving state of the motor includes gear shifting drive and reference position learning drive, and the rising temperature is inferred based on whether the driving state of the motor is gear shifting drive or reference position learning drive" can also be combined with various disclosures related to motor control devices.

[0078] The disclosure of "estimating the temperature drop based on the difference between the component temperature and the reference temperature" can also be combined with various disclosures related to motor control devices.

[0079] The disclosure that “the control unit has a fault determination unit (55) for determining the fault of the temperature sensor, and the temperature estimation unit sets the reference temperature to a predetermined value when the temperature sensor malfunctions” can also be combined with various disclosures related to motor control devices.

[0080] The disclosure that "the motor is an actuator related to gear shifting, and gear shifting is prohibited when the estimated temperature of the component is higher than the high temperature determination threshold" can also be combined with various disclosures related to motor control devices.

[0081] The disclosure that “the control unit has a temperature storage unit (59) for storing the element temperature at the time of termination, wherein the element temperature at the time of termination is the element temperature when the power is disconnected, and the temperature estimation unit sets the initial value of the element temperature when the power is turned on as the element temperature at the time of termination” can also be combined with various disclosures related to motor control devices.

[0082] The disclosure that “the control unit has a temperature storage unit (59) that stores the component temperature at termination and the reference temperature at termination, wherein the component temperature at termination is the component temperature when the power is disconnected and the reference temperature at termination is the reference temperature when the power is disconnected, and the temperature estimation unit sets the initial value of the component temperature at the time of power-on as the reference temperature when the temperature drop of the reference temperature during the period from power-off to power-on is greater than a determination threshold, and sets the initial value of the component temperature at the time of power-on as the component temperature at termination when the temperature drop of the reference temperature during the period from power-off to power-on is less than the determination threshold” can also be combined with various disclosures related to motor control devices.

[0083] The disclosure that “the control unit has a temperature storage unit (59) for storing the component temperature at the time of termination, wherein the component temperature at the time of termination is an estimated value of the component temperature when the power is disconnected, and the temperature estimation unit sets the initial value of the component temperature at the time of termination to the reference temperature at the time of power connection when the reference temperature at the time of power connection is higher than the component temperature at the time of termination” can also be combined with various disclosures related to motor control devices.

[0084] The control unit and method described in this disclosure can also be implemented using a dedicated computer, which is provided by comprising a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and method described in this disclosure can also be implemented using a dedicated computer provided by a processor composed of one or more dedicated hardware logic circuits. Alternatively, the control unit and method described in this disclosure can also be implemented using one or more dedicated computers composed of a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. Furthermore, the computer program can also be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. The present disclosure is not limited to the above embodiments and can be implemented in various ways without departing from its spirit.

[0085] This disclosure is based on embodiments. However, this disclosure is not limited to these embodiments and constructions. This disclosure also includes various modifications and equivalent variations. In addition, various combinations and methods, as well as other combinations and methods that include only one element or more of them, also fall within the scope and spirit of this disclosure.

Claims

1. A motor control device, characterized in that, have: The drive circuit (41) has a drive element that switches the energization of the motor (10); and The control unit (50) includes a drive state acquisition unit (53) for acquiring the drive state of the motor, a reference temperature calculation unit (581) for calculating the ambient temperature of the drive element as a reference temperature based on the detection value of the temperature sensor (45), and a temperature estimation unit (582) for estimating the temperature of the drive element, i.e., the element temperature. If it is determined that motor drive has been implemented, the temperature estimation unit estimates the rising temperature based on the motor drive state and the reference temperature. If it is determined that no motor drive is being implemented, the temperature estimation unit estimates the temperature drop based on the reference temperature. The temperature estimation unit updates the estimated value of the element temperature based on the rising temperature or the falling temperature.

2. The motor control device according to claim 1, characterized in that, The rising temperature is estimated based on the difference between the component temperature and the reference temperature.

3. The motor control device according to claim 2, characterized in that, The control unit includes a voltage detection unit (52) for detecting the applied voltage applied to the drive circuit. The temperature rise is estimated based on the applied voltage.

4. The motor control device according to any one of claims 1 to 3, characterized in that, The motor is an actuator related to gear shifting. The driving state of the motor includes the gear shift angle. The temperature rise is estimated based on the gear shift angle during this gear shift.

5. The motor control device according to any one of claims 1 to 3, characterized in that, The motor is an actuator related to gear shifting. The driving state of the motor includes gear shifting time. The temperature rise is estimated based on the gear shifting time in this gear shift.

6. The motor control device according to any one of claims 1 to 3, characterized in that, The motor is an actuator related to gear shifting. The motor's driving states include gear shifting drive and reference position learning drive. The rising temperature is estimated based on whether the motor's driving state is gear shifting drive or reference position learning drive.

7. The motor control device according to claim 1, characterized in that, The temperature drop is estimated based on the difference between the component temperature and the reference temperature.

8. The motor control device according to claim 7, characterized in that, The temperature drop is estimated based on the elapsed time since the motor's drive was terminated, with a shorter elapsed time indicating a greater temperature drop.

9. The motor control device according to claim 1, characterized in that, The control unit includes a fault determination unit (55) for determining the fault of the temperature sensor. In the event of a malfunction of the temperature sensor, the temperature estimation unit sets the reference temperature to a predetermined value.

10. The motor control device according to claim 1, characterized in that, The motor is an actuator related to gear shifting. If the estimated temperature of the component is higher than the high temperature threshold, gear switching is prohibited.

11. The motor control device according to claim 1, characterized in that, The control unit has a temperature storage unit (59) that stores an estimated value of the component temperature when the power is disconnected, i.e., the component temperature at termination. The temperature estimation unit sets the initial value of the component temperature when the power is turned on as the component temperature when the power is terminated.

12. The motor control device according to claim 1, characterized in that, The control unit has a temperature storage unit (59) that stores the estimated value of the component temperature when the power is disconnected, i.e., the component temperature at termination, and the reference temperature when the power is disconnected, i.e., the reference temperature at termination. If the temperature drop of the reference temperature during the period from power-off to power-on exceeds a determination threshold, the temperature estimation unit sets the initial value of the component temperature at the time of power-on as the reference temperature at the time of power-on. If the temperature drop of the reference temperature during the period from power disconnection to power reconnection is below the determination threshold, the temperature estimation unit sets the initial value of the component temperature at the time of power connection as the component temperature at the time of termination.

13. The motor control device according to claim 1, characterized in that, The control unit has a temperature storage unit (59) that stores an estimated value of the component temperature when the power is disconnected, i.e., the component temperature at termination. If the reference temperature at the time of power-on is higher than the component temperature at the time of power-off, the temperature estimation unit sets the initial value of the component temperature at the time of power-on as the reference temperature at the time of power-on.

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