Control device and control method

Abstract

Provided is a control device and a control method that can accurately estimate the temperature of a temperature estimation site without relying on detection information from sensors other than temperature sensors, even when a temperature sensor is installed at a position remote from the temperature estimation site. The control device (30) includes a sensor temperature detection unit (32) that detects the temperature of a sensor based on an output signal from a temperature sensor (3) installed on a temperature estimation target object (10), and a temperature estimation unit (33) that calculates an estimated temperature (T2e) of the temperature estimation site based on a detected value of the current sensor temperature or a corrected value of the current sensor temperature, a detected value of the sensor temperature or a corrected value of the sensor temperature at a time step before the current time step, and a thermal time constant.

Description

TECHNICAL FIELD

[0001] The present application relates to a control device and a control method. BACKGROUND

[0002] In order to avoid damage to the device due to temperature rise, a structure in which a temperature sensor is attached to the device is widely known. Using one method, a temperature sensor is attached near a part having the highest temperature or a part requiring overheat protection, and the output of the device is limited or stopped when a predetermined temperature is exceeded.

[0003] However, temperature deviation occurs between the temperature monitoring part of the device and the sensor part in the temperature sensor for the following reasons. The first reason is that the temperature detection value has a response delay due to the heat capacity of the temperature sensor and the sensor part itself. The second reason is that there is thermal resistance between the temperature monitoring part and the sensor part, and a temperature difference occurs even in a steady state. Due to the restrictions on the structure of the device, sometimes it is not possible to arrange the temperature sensor near the temperature monitoring part of the device. In addition, when measuring the temperature of a coil that generates high voltage such as a rotating electric machine, the thermal resistance increases because an electrically insulating member having a small thermal conductivity is arranged between the temperature sensor and the coil.

[0004] When temperature deviation occurs between the temperature monitoring part and the sensor part, it can lead to a decrease in the reliability of the device. Therefore, it is necessary to set the temperature at which the output is limited or stopped to a temperature lower than the heat resistance temperature of the device, but when the margin increases, it can lead to the device becoming large. In particular, in a rotating electric machine for vehicle use, a higher reliability is assumed as a premise, and a small size and high output are required, so the coexistence of reliability and small size and high output becomes a problem.

[0005] In order to solve these problems, in the technology of Patent Literature 1, the accuracy of the estimated temperature is improved by (1) calculation of loss, (2) condition determination of whether the temperature is in a rising state or a falling state, (3) selection of a thermal time constant based on a speed command value and a current command value, (4) temperature estimation based on information of the above (1) to (3), and the like.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent Laid-Open No. 2017-63540 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, in the technology of Patent Literature 1, in order to perform the condition determination, more sensors are required in addition to the temperature sensor, and thus the cost increases, and a physical space for disposing the more sensors is required, and thus there is a problem of device upsizing. In addition, there is a problem that the number of input signals to the control device increases, and the load of the operation processing of the temperature estimation increases, and thus the cost of the control device increases.

[0011] In addition, in the technology of Patent Literature 1, in the temperature estimation, the loss needs to be calculated, and since various assumptions are included in the calculation, a difference between the actual loss and the calculated loss occurs, and becomes an error factor of the temperature estimation. In particular, when heat generation other than the expected heat generation such as short circuit occurs, a large deviation between the actual loss and the calculated loss occurs, and the error of the temperature estimation becomes large. Therefore, in consideration of the abnormal heat generation, a temperature much lower than the heat resistance temperature of the device needs to be set as the determination value of the limited output, and thus the device upsizes.

[0012] Therefore, an object of the present application is to provide a control device and a control method that can estimate the temperature of a temperature estimation site with high precision without depending on detection information of sensors other than a temperature sensor even when the temperature sensor is installed at a position far from the temperature estimation site.

[0013] Technical means for solving the technical problem

[0014] The control device according to the present application includes:

[0015] a sensor temperature detection section that detects a sensor temperature based on an output signal of a temperature sensor installed on a temperature estimation target; and

[0016] a temperature estimation section that calculates an estimated temperature of a temperature estimation site provided inside the temperature estimation target, based on a detected value of the sensor temperature at present, or a correction value of a sensor temperature at present calculated based on the detected value of the sensor temperature at present, a detected value of the sensor temperature at a time step before, or a correction value of the sensor temperature at the time step before, and a thermal time constant from the temperature of the temperature estimation site to the sensor temperature.

[0017] The control method according to the present application includes:

[0018] a sensor temperature detection step of detecting a sensor temperature based on an output signal of a temperature sensor installed on a temperature estimation target; and

[0019] a temperature estimation step in which an estimated temperature of a temperature estimation site is calculated based on a detected value of the current sensor temperature or a corrected value of the current sensor temperature calculated based on the detected value of the current sensor temperature, a detected value of the sensor temperature before a time step or a corrected value of the sensor temperature before the time step, and a thermal time constant from a temperature of the temperature estimation site set inside the temperature estimation target to the sensor temperature.

[0020] Effects of Invention

[0021] According to the control device and the control method of the present application, using only the detected value of the sensor temperature, the temperature of the temperature estimation site can be estimated including transient response by the change of the sensor temperature or the corrected value of the sensor temperature before and after the time step and the thermal time constant from the temperature of the temperature estimation site to the sensor temperature, and since the thermal time constant from the temperature of the temperature estimation site to the sensor temperature is taken into account, the temperature can be estimated with high precision even if there is a distance between the temperature estimation site and the temperature sensor. Therefore, even if the temperature sensor cannot be disposed near the temperature estimation site, the estimation precision can be maintained. Thus, the degree of freedom of the installation position of the temperature sensor can be improved.

[0022] In addition, since the heat generation amount does not need to be estimated using information other than the detected value of the sensor temperature, such as the current value, etc., the temperature estimation error can be suppressed in the case where the heat generation amount estimation error due to various deviation factors such as manufacturing deviation, annual change, condition change, etc., and the heat generation amount estimation error due to unexpected heat generation such as short circuit, etc. Therefore, even in the case where the heat generation amount variation due to various deviation factors occurs, or the unexpected heat generation such as short circuit, etc. occurs, the temperature can be estimated with high precision based on the detected value of the sensor temperature that shows the variation of the heat generation amount, thereby improving the reliability of the system.

[0023] Since the detected value of the sensor temperature is used, other information such as the current value, etc. does not need to be used, the number of input signals input to the control device can be reduced, and the device can be simplified. In addition, since the detected value of the sensor temperature is used for the operation, a complex operation using a plurality of parameters such as the current value, etc. does not need to be performed, and the operation processing load can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic configuration diagram of the temperature estimation target, the temperature sensor, and the control device according to Embodiment 1.

[0025] Figure 2 is a schematic hardware configuration diagram of the control device according to Embodiment 1.

[0026] Figure 3is a diagram illustrating a thermal circuit model related to Embodiment 1.

[0027] Figure 4 is a flowchart illustrating a control method related to Embodiment 1.

[0028] Figure 5 is a timing chart illustrating a temperature estimation behavior related to Embodiment 2.

[0029] Figure 6 is a flowchart illustrating a control method related to Embodiment 2.

[0030] Figure 7 is a schematic configuration diagram of a rotating electric machine, an inverter, and a control device related to Embodiment 3.

[0031] Figure 8 is a cross-sectional view of a rotating electric machine related to Embodiment 3.

[0032] Figure 9 is a circuit diagram of an inverter related to Embodiment 3.

[0033] Figure 10 is a schematic configuration diagram of a rotating electric machine, an inverter, and a control device related to Embodiment 4. DETAILED DESCRIPTION

[0034] 1. Embodiment 1

[0035] Hereinafter, a control device 30 related to Embodiment 1 will be described with reference to the drawings. Figure 1 is a schematic configuration diagram of a temperature estimation target object 10, a temperature sensor 3, the control device 30, and the like.

[0036] The temperature sensor 3 is attached to the temperature estimation target object 10 provided on the device 1. The temperature sensor 3 has a sensor portion 4 and a sensor protection portion 5 that covers and protects the periphery of the sensor portion 4. The sensor portion 4 uses a thermistor or the like. The sensor protection portion 5 is made of resin, a metal case, or the like. The temperature sensor 3 has a heat capacity C. In particular, the heat capacity of the sensor protection portion 5 is large and cannot be ignored. The surface of the sensor protection portion 5 abuts against the surface of the temperature estimation target object 10 and is attached. The temperature of the sensor portion 4 changes in accordance with the temperature of the periphery of the sensor protection portion 5. The output signal of the temperature sensor 3 is input to the control device 30.

[0037] The temperature estimation target object 10 has a circuit, and the temperature increases and decreases in accordance with an increase and decrease in the amount of heat generated by the circuit. The amount of heat generated by the circuit increases and decreases in accordance with the amount of power consumption. Coils, circuit elements, wiring, and the like are used for the circuit. The power consumption of the circuit is controlled by the control device 30. Inside the temperature estimation target object 10, a temperature estimation site 11, which is estimated by a temperature estimation section 33 described later, is provided. For example, the temperature estimation site 11 is provided at a site where the temperature is highest or a site where overheat protection is required.

[0038] 1-1. Control device 30

[0039] As shown in FIG. 1, the control device 30 includes a device control section 31, a sensor temperature detection section 32, and a temperature estimation section 33, and the like. Each function of the control device 30 is realized by a processing circuit included in the control device 30. Specifically, as shown in FIG. 2, the control device 30 includes an arithmetic processing device 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 that exchanges data with the arithmetic processing device 90, an input circuit 92 that inputs an external signal to the arithmetic processing device 90, and an output circuit 93 that outputs a signal from the arithmetic processing device 90 to the outside, and the like, as the processing circuit. Figure 1 Figure 2

[0040] As the arithmetic processing device 90, an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, various signal processing circuits, and the like can be included. In addition, as the arithmetic processing device 90, a plurality of arithmetic processing devices of the same kind or different kinds can be provided to share the execution of each process. As the storage device 91, various storage devices such as a RAM (Random Access Memory), a ROM (Read Only Memory), and an EEPROM (Electrically Erasable Programmable Read-Only Memory) are included. The input circuit 92 is connected to various sensors such as the temperature sensor 3, and includes an A / D converter or the like that inputs an output signal of each sensor to the arithmetic processing device 90. The output circuit 93 is connected to an electric load such as the circuit of the temperature estimation target object 10, and includes a drive circuit or the like that outputs a control signal from the arithmetic processing device 90 to each electric load.​​

[0041] Moreover, each function of each control section 31 to 33 and the like possessed by the control device 30 is realized by executing software (program) stored in a storage device 91 such as a ROM by the arithmetic processing device 90, and in cooperation with other hardware of the control device 30 such as the storage device 91, an input circuit 92, and an output circuit 93. In addition, the setting data of the thermal time constant τ, the determination value, and the like used by each control section 31 to 33 and the like are stored in the storage device 91 such as a ROM as a part of the software (program). Hereinafter, each function of the control device 30 will be described in detail.

[0042] 1-1-1. Device Control Section 31

[0043] The device control section 31 controls the power consumption of the temperature estimation target object 10. In the present embodiment, the device control section 31 changes the amount of energization to the circuit of the temperature estimation target object 10. The device control section 31 suppresses the heat generation of the temperature estimation target object 10 based on the estimation temperature T2e of the temperature estimation site estimated by the temperature estimation section 33. For example, in the case where the estimation temperature T2e of the temperature estimation site exceeds the determination value, the device control section 31 reduces the power consumption of the temperature estimation target object 10, thereby reducing the temperature of the temperature estimation site 11.

[0044] 1-1-2. Sensor Temperature Detection Section 32

[0045] The sensor temperature detection section 32 detects the sensor temperature T1 based on the output signal of the temperature sensor 3. For example, the sensor temperature detection section 32 detects the sensor temperature T1det at each predetermined operation cycle.

[0046] The sensor temperature detection section 32 stores the detected value T1det of the sensor temperature at each time in the storage device 91 such as a RAM. The temperature estimation section 33 described later reads the detected value T1detold of the sensor temperature detected at a time step ΔT ahead of the present time from the storage device 91.

[0047] 1-1-3. Temperature Estimation Section 33

[0048] <Thermal Circuit Model>

[0049] Figure 3 A thermal circuit model is shown. Here, T2 is the temperature of the temperature estimation site 11, T1 is the temperature of the sensor section 4, and T0 is the temperature of the surroundings of the temperature sensor 3. The temperature T0 of the surroundings of the temperature sensor is the temperature of a gas such as air around the temperature sensor 3 or the temperature of a liquid refrigerant such as water or oil around the temperature sensor 3.

[0050] R21 is a thermal resistance [K / J-s] between the temperature estimation site 11 and the sensor portion 4, and R10 is a thermal resistance [K / J-s] between the sensor portion 4 and the surroundings of the temperature sensor. The thermal resistance is a value indicating the easiness of temperature transfer, and means the amount of temperature change [K] per unit time per heat flow [J / s].

[0051] The heat capacity C of the temperature sensor 3 is the heat capacity [J / K] of the entire member of the temperature sensor 3 integrated with the sensor portion 4, and in the present example, is the heat capacity of the sensor portion 4 and the sensor protection portion 5. The heat capacity C of the temperature sensor 3 is a value obtained by multiplying the mass m of the temperature sensor 3 by the specific heat capacity c.

[0052] For example, the temperature estimation site 11 of the temperature estimation object 10 is set at a site where the temperature is the highest or a site where overheat protection is required, and is located at or near a heat generation source.

[0053] Derivation of the estimation method when R21 < R10

[0054] The temperature estimation method when the thermal resistance R10 between the sensor portion 4 and the surroundings of the temperature sensor is sufficiently large with respect to the thermal resistance R21 between the temperature estimation site 11 and the sensor portion 4 will be described. For example, the surface of the temperature sensor 3 other than the contact portion with the temperature estimation object 10 is thermally insulated from the gas or liquid of the surroundings. Alternatively, the entire temperature sensor 3 can be surrounded by the temperature estimation object 10 and cut off from the gas or liquid of the surroundings.

[0055] In this case, the temperature T1 of the sensor portion does not change depending on the temperature T0 of the surroundings of the temperature sensor, but changes depending on the temperature T2 of the temperature estimation site. Therefore, the temperature T0 of the surroundings of the temperature sensor can not be considered.

[0056] In a steady state, T1 « T2, and in a transient state, with respect to the change in the temperature T2 of the temperature estimation site, the change in the temperature T1 of the sensor portion has a time delay. The time constant τ [s] (hereinafter referred to as a thermal time constant τ) of the time delay from the temperature T2 of the temperature estimation site to the sensor temperature T1 is a multiplication value of the heat capacity C [J / K] of the temperature sensor and the thermal resistance R21 [K / J-s] between the temperature estimation site 11 and the sensor portion 4, as shown in the following equation.

[0057] τ = R21 x C...(1)

[0058] C = m x c

[0059] A temperature change from a sensor temperature T1old [K] before a time step ΔT to a current sensor temperature T1now [K], and a heat flow rate Wdt [J / s] per unit time flowing into the temperature sensor 3 during this period, between which the heat capacity C [J / K] of the temperature sensor 3 and the time step ΔT [s] are used, satisfy the following equation.

[0060] (T1now - T1old) x C / ΔT = Wdt... (2)

[0061] In addition, a temperature difference between the current temperature T2now [K] of the temperature estimation site and the current sensor temperature T1now [K], and a heat flow rate Wdt [J / s] per unit time input to the thermal resistance R21, between which the thermal resistance R21 [K / J-s] is used, satisfy the following equation.

[0062] (T2now - T1now) / R21 = Wdt... (3)

[0063] Substituting equation (1) and equation (2) into equation (3), the temperature T2now of the current temperature estimation site is obtained as the following equation.

[0064] T2now = T1now + τ x (T1now - T1old) / ΔT... (4)

[0065] As shown in equation (2) based on equation (4), it is possible to estimate the equivalent value of the heat flow rate Wdt flowing into the temperature sensor 3 from the temperature estimation object 10 based on a value obtained by dividing the amount of change in the sensor temperature (T1now - T1old) between the time steps ΔT by the time step ΔT. In addition, in the case of a method of estimating the heat generation amount using a current value or the like, since the estimation error of the heat generation amount due to various deviation factors such as manufacturing deviation, annual change, condition change, and the estimation error of the heat generation amount due to unexpected heat generation such as short circuit, it is possible to cause a temperature estimation error. On the other hand, since it is possible to estimate the equivalent value of the fluctuating heat flow rate Wdt from the amount of change in the sensor temperature between the time steps ΔT, even in the case where the fluctuation of the heat generation amount due to various deviation factors occurs, or the case where unexpected heat generation such as short circuit occurs, it is possible to maintain the estimation accuracy.

[0066] Then, as shown in Equation (3) based on Equation (4), the temperature T2now of the temperature estimation site can be inversely calculated and estimated based on the equivalent value of the estimated heat flow Wdt, the current sensor temperature T1now, and the thermal time constant τ. Also, as shown in Equation (1) based on Equation (4), the thermal time constant τ corresponds to the product of the heat capacity C and the thermal resistance R21 of the temperature sensor, and thus the heat capacity C of Equation (2) and the thermal resistance R21 of Equation (3) are taken into account in the calculation of Equation (4). Also, in the calculation of Equation (4), the response delay caused by the thermal time constant τ is taken into account. Also, in the steady state, (T1now - T1old) = 0, and T2now = T1now. Thus, in the steady state, it is possible to suppress the occurrence of a stable deviation between the temperature T2now of the temperature estimation site and the actual temperature.

[0067] Thus, according to Equation (4), even in the case where a variation in the amount of heat generation caused by various deviation factors occurs, or in the case where unexpected heat generation such as short circuit occurs, it is possible to estimate the estimated temperature T2e of the temperature estimation site with high accuracy in the transient state and the steady state by the change in the sensor temperature (T1detnow - T1detold) between the time steps ΔT and the thermal time constant τ.

[0068] <Structure of the temperature estimation unit 33>

[0069] Thus, the temperature estimation unit 33 calculates the estimated temperature T2e of the temperature estimation site based on the detected value T1detnow of the current sensor temperature, the detected value T1detold of the sensor temperature before the time step ΔT, and the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1.

[0070] According to this structure, it is possible to estimate the temperature T2 of the temperature estimation site including the transient response based on the change in the detected value of the sensor temperature before and after the time step ΔT and the thermal time constant τ only by using the detected value T1det of the sensor temperature. Since the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1 is taken into account, it is possible to estimate the temperature with high accuracy even if there is a distance between the temperature estimation site 311 and the temperature sensor. Thus, it is possible to maintain the estimation accuracy even if the temperature sensor 3 cannot be disposed in the vicinity of the temperature estimation site 11. Thus, it is possible to improve the degree of freedom in the installation position of the temperature sensor 3.

[0071] In addition, since the amount of heat generation is estimated without using information other than the temperature detection value, such as a current value, and the like, a temperature estimation error does not occur due to an estimation error of the amount of heat generation caused by various deviation factors, such as a manufacturing deviation, a change over time, a change in conditions, and the like, and an estimation error of the amount of heat generation caused by unexpected heat generation, such as a short circuit. Therefore, even in a case where the amount of heat generation varies due to various deviation factors, such as a manufacturing deviation, a change over time, a change in conditions, and the like, or unexpected heat generation, such as a short circuit, occurs, the temperature can be estimated with high precision based on the detection value T1det of the sensor temperature that exhibits a variation in the amount of heat generation, and thus the reliability of the system can be improved.

[0072] Since the detection value of the sensor temperature is used, other information, such as a current value, and the like, does not need to be used, the number of input signals input to the control device 30 can be reduced, and simplification of the device can be achieved. In addition, since the detection value of the sensor temperature is used for the operation, a complex operation using a plurality of parameters, such as a current value, and the like, does not need to be performed, and the operation processing load can be reduced.

[0073] In the present embodiment, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site based on the detection value T1detnow of the current sensor temperature and the detection value T1detold of the sensor temperature before the time step ΔT using the following expression corresponding to Expression (4).

[0074] T2e = T1detnow + τ x (T1detnow - T1detold) / ΔT... (5)

[0075] As indicated by Expression (2) based on Expression (5), the equivalent value of the heat flow rate Wdt flowing into the temperature sensor 3 from the temperature estimation object 10 can be estimated based on a value obtained by dividing the amount of change in the sensor temperature (T1detnow - T1detold) between the time steps ΔT by the time step ΔT. Therefore, as described above, even in a case where a variation in the amount of heat generation due to various deviation factors, such as a manufacturing deviation, a change over time, a change in conditions, and the like, occurs, or unexpected heat generation, such as a short circuit, occurs, the equivalent value of the varied heat flow rate Wdt can be estimated from the amount of change in the sensor temperature between the time steps ΔT, and thus the estimation precision can be maintained with respect to the variation in the amount of heat generation.

[0076] Then, as shown in Equation (3) based on Equation (5), the estimated temperature T2e of the temperature estimation site can be inversely calculated and estimated based on the equivalent value of the estimated heat flow Wdt, the detected value T1detnow of the current sensor temperature, and the thermal time constant τ. In addition, as shown in Equation (1) based on Equation (5), the thermal time constant τ corresponds to the product value of the heat capacity C and the thermal resistance R21 of the temperature sensor, and thus the heat capacity C of Equation (2) and the thermal resistance R21 of Equation (3) are taken into account in the calculation of Equation (5). In addition, in the calculation of Equation (5), the response delay caused by the thermal time constant τ is taken into account. Specifically, the detected value T1det of the sensor temperature is subjected to first-order forward processing corresponding to the thermal time constant τ, and the estimated temperature T2e of the temperature estimation site is calculated. In addition, in a steady state, (T1detnow - T1detold) = 0, and T2e = T1detnow. Thus, in a steady state, it is possible to suppress the occurrence of a stable deviation between the estimated temperature T2e of the temperature estimation site and the actual temperature.

[0077] Thus, according to Equation (5), even in a case where a variation in the amount of heat generation caused by various deviation factors occurs, or in a case where unexpected heat generation such as short circuit occurs, it is possible to estimate the estimated temperature T2e of the temperature estimation site with high accuracy in a transient state and a steady state by the change in the sensor temperature between time steps ΔT (T1detnow - T1detold) and the thermal time constant τ.

[0078] The time step ΔT can be set to the detection period of the sensor temperature or the calculation period of the estimated temperature T2e, or can be set to a period longer than the detection period of the sensor temperature or the calculation period of the estimated temperature T2e.

[0079] <Setting of Thermal Time Constant τ>

[0080] The thermal time constant τ is set to a value calculated using the heat capacity C of the temperature sensor and the thermal resistance R21 between the temperature estimation site 11 and the sensor portion 4 by Equation (1). According to this structure, the heat capacity C and the thermal resistance R21 of the temperature sensor can be easily obtained based on the specifications of the components, and thus it is possible to set the thermal time constant τ without performing experiments on the entire device, thereby reducing development costs.

[0081] Alternatively, the thermal time constant τ can be set to a value calculated based on measured data at the time of temperature rise. For example, the thermal resistance R21 sometimes includes a thermal resistance that is difficult to model, such as a contact thermal resistance, and can be set based on measured data. In a case where the amount of heat generation of the temperature estimation target object 10 is allowed to change in steps, the time elapsed after the step change until the detection value T1det of the temperature sensor reaches about 63.2% of the final value is measured, and the measured elapsed time is set as the thermal time constant τ. The temperature estimation section 33 can measure the elapsed time after the step change on-line and set the thermal time constant τ. Alternatively, the elapsed time after the step change can be measured in advance through experiments off-line, and the thermal time constant τ can be set in advance.

[0082] <Overheat Protection>

[0083] Either of the setting of the thermal time constant τ based on the formula (1) and the setting of the thermal time constant τ based on measured data can be used, but temperature estimation using the thermal time constant τ is effective in the case of overheat protection of the temperature estimation target object 10. Specifically, since the temperature changes rapidly in the case where abnormal heat generation due to a short circuit or the like occurs, an overshoot of the temperature of the temperature estimation site 11 occurs even in the case where power consumption is reduced when the estimated temperature of the temperature estimation site 11 estimated with high precision exceeds the determination value. Therefore, in consideration of abnormal heat generation, a temperature much lower than the heat resistance temperature of the device has to be set as the determination value, resulting in a large size of the device.

[0084] In the case where such abnormal heat generation causes a rapid temperature rise, the temperature of the temperature sensor 3 locally rises, the detection value T1det of the sensor temperature is greater than the average temperature of the entire sensor, and the heat capacity becomes small. At this time, the thermal time constant τ used by the temperature estimation section 33 is greater than the actual thermal time constant, and therefore, as in the case of Embodiment 2 described later, Figure 5 , the estimated temperature T2e is greater than the actual value of the temperature T2 of the temperature estimation site 11. Therefore, in the case where the temperature changes greatly, the estimated temperature T2e exceeds the determination value before the actual value of the temperature T2 of the temperature estimation site 11 exceeds the determination value, and power consumption can be reduced. Therefore, even if a temperature corresponding to the heat resistance temperature of the device is set as the determination value, an overshoot of the temperature can be suppressed, and the reliability of the device can be maintained. Therefore, the device can be suppressed from being large-sized.

[0085] In addition, in the case of a temperature change that is generally assumed to be relatively slow, the thermal time constant τ used by the temperature estimation unit 33 coincides with the actual response time constant, so the estimation accuracy is maintained. In the case of such a relatively gentle temperature change, even after the power consumption is reduced, the overshoot amount of the temperature does not become large. Therefore, even if the temperature corresponding to the heat resistance temperature of the device is set as the determination value, the reliability of the device can be maintained, and the device can be suppressed from becoming large.

[0086] As described above, according to the temperature estimation using the thermal time constant τ, by utilizing the physical phenomenon in which the actual thermal time constant is smaller than the thermal time constant τ used by the temperature estimation unit 33 at the time of abnormal heat generation, even if both the abnormal heat generation and the normal heat generation are considered, it is possible to set the determination value to the temperature corresponding to the heat resistance temperature of the device, to maintain the reliability of the device, and to suppress the device from becoming large.

[0087] <Setting of a large thermal time constant τ>

[0088] The larger of the value of the thermal time constant calculated by the formula (1) and the value of the thermal time constant calculated based on the measured data at the time of temperature rise can be set as the thermal time constant τ. If the thermal time constant τ used by the temperature estimation unit 33 is set to be larger than the actual thermal time constant, the phase advances, and even at the time of normal heat generation, the estimated temperature T2e is larger than the actual value of the temperature T2 of the temperature estimation unit 11. Therefore, it is possible to reduce the power consumption in advance, and to further improve the reliability of the device.

[0089] In addition, as a design matter for adjusting the temperature margin of the device, a value obtained by multiplying the thermal time constant calculated according to the formula (1) or the measured data by a coefficient of about 0.5 to 2 is set as the thermal time constant τ. Furthermore, when the heat capacity C has temperature dependency or the like and the thermal time constant changes depending on the temperature or the like operation state, the temperature estimation unit 33 can change the thermal time constant τ depending on the estimated temperature T2e or the like operation state.

[0090] <Control method>

[0091] Figure 4 A flowchart related to the control method of the present embodiment is shown. In step S01, as described above, a time constant setting step in which the thermal time constant τ is set to the value calculated according to the formula (1) is executed. The time constant setting step can be executed by the temperature estimation unit 33, or can be executed by the designer in advance.

[0092] Alternatively, in step S01, the time constant setting step in which the thermal time constant τ is set to a value calculated based on the measured data at the time of temperature rise can be executed as described above. The time constant setting step can be executed by the temperature estimation section 33 or can be executed by the designer in advance.

[0093] In step S02, the sensor temperature detection step in which the sensor temperature detection section 32 detects the sensor temperature Tl based on the output signal of the temperature sensor 3 is executed as described above.

[0094] In step S03, the temperature estimation step in which the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site based on the detected value Tldetnow of the current sensor temperature, the detected value Tldetold of the sensor temperature before the time step ΔT, and the thermal time constant τ from the temperature of the temperature estimation site T2 to the sensor temperature Tl is executed as described above. In the present embodiment, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site based on the detected value Tldetnow of the current sensor temperature and the detected value Tldetold of the sensor temperature before the time step ΔT using Equation (5).

[0095] In step S04, the device control step in which the device control section 31 controls the power consumption of the temperature estimation target object 10 is executed. The device control section 31 suppresses the heat generation of the temperature estimation target object 10 based on the estimated temperature T2e of the temperature estimation site estimated by the temperature estimation section 33.

[0096] Steps S02 to S04 are repeatedly executed for each operation cycle. On the other hand, step S01 is executed at each operation cycle, the design stage, or the time of temperature rise.

[0097] 2. Embodiment 2

[0098] The control device 30 related to Embodiment 2 is described. The same structure as that of Embodiment 1 is omitted from the description. The basic structure of the control device 30 related to the present embodiment is the same as that of Embodiment 1, but the temperature estimation method is different from that of Embodiment 1.

[0099] <Estimation method when R10 cannot be ignored>

[0100] A temperature estimation method when the thermal resistance R10 between the sensor portion 4 and the surroundings of the temperature sensor is sufficiently large and cannot be ignored in relation to the thermal resistance R21 between the temperature estimation site 11 and the sensor portion 4, which is different from Embodiment 1, will be described. For example, the surface of the temperature sensor 3 is not thermally insulated from the gas or liquid of the surroundings, and the heat conduction between the temperature sensor 3 and the surroundings of the temperature sensor cannot be ignored.

[0101] In this case, the sensor temperature T1 varies depending on the temperature of the surroundings of the temperature sensor T0 and the temperature of the temperature estimation site T2. Therefore, the temperature of the surroundings of the temperature sensor T0 needs to be taken into account.

[0102] In this case, even in the steady state, T1≠ T2, and therefore an error occurs in the estimation method using the formula (4) or the formula (5) of Embodiment 1. Therefore, as shown in the following formula derivation, a corrected value T1cr of the sensor temperature is used in place of the detected value T1det of the sensor temperature in the formula (4) or the formula (5).

[0103] In the steady state, the heat flow from the temperature estimation object 10 to the temperature sensor 3 and the heat flow from the temperature sensor 3 to the surroundings of the temperature sensor become constant values. Therefore, as shown in the following formula, the heat flow Wdt [J / s] calculated by dividing the temperature difference between the temperature T2now [K] of the current temperature estimation site and the current sensor temperature T1now [K] by the thermal resistance R21 [K / J·s] between the temperature estimation site 11 and the sensor portion 4 is equal to the heat flow Wdt [J / s] calculated by dividing the temperature difference between the current sensor temperature T1now [K] and the current temperature of the surroundings of the temperature sensor T0now [K] by the thermal resistance R10 [K / J·s] between the sensor portion 4 and the surroundings of the temperature sensor.

[0104] (T2now - T1now) / R21 = (T1now - T0now) / R10 = Wdt... (6)

[0105] The formula (6) is rearranged for the temperature T2now of the current temperature estimation site, and the following formula is obtained.

[0106] T2now = T1now + (T1now - T0now) x R21 / R10 = T1crnow... (7)

[0107] Therefore, using Equation (7), the temperature T2 of the temperature estimation site in the steady state can be estimated based on the sensor temperature T1. Since this temperature T2 of the temperature estimation site in the steady state is interpreted as a temperature obtained by scaling the sensor temperature T1 to an equivalent value of the temperature T2 of the temperature estimation site, this temperature T2 of the temperature estimation site in the steady state is referred to as a correction value T1cr of the sensor temperature. That is, as in the case of Equations (4) and (5), the correction value T1cr of the sensor temperature such as T2 = T1cr is calculated in the steady state. On the other hand, in the transient state, there is a response delay corresponding to the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1, from the actual temperature of the temperature estimation site to the temperature T2 of the temperature estimation site in the steady state.

[0108] Therefore, by using the correction value T1cr of the sensor temperature instead of the sensor temperature T1 of Equation (4) in the following equation, the temperature T2 of the temperature estimation site in the steady state and the transient state can be estimated. In this equation, T1crnow is the correction value of the current sensor temperature, and T1crold is the correction value of the sensor temperature at the time step ΔT ago.

[0109] T2now = T1crnow + τ x (T1crnow - T1crold) / ΔT

[0110] T1crnow = T1now + (T1now - T0now) x R21 / R10... (8)

[0111] According to Equation (8), the thermal resistance R10 cannot be ignored with respect to the thermal resistance R21, and even in the case where T1 ≠ T2 in the steady state, by using the ratio of the thermal resistance R21 to the thermal resistance R10 and using the correction value T1cr of the sensor temperature obtained by scaling the sensor temperature T1 to an equivalent value of the temperature T2 of the temperature estimation site in the steady state, the temperature T2 of the temperature estimation site can be estimated. Therefore, in the steady state, T2 = T1cr, and the estimation accuracy in the steady state can be improved. In addition, since the thermal time constant τ is used, as in Equation (4), the response delay due to the heat capacity C and the thermal resistance R21 can be simulated.

[0112] <Structure of the temperature estimation unit 33>

[0113] Therefore, in the present embodiment, the temperature estimation unit 33 calculates the estimated temperature T2e of the temperature estimation site based on the correction value T1crnow of the current sensor temperature calculated based on the detected value T1detnow of the current sensor temperature, the correction value T1crold of the sensor temperature at the time step ΔT ago, and the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1.

[0114] According to this configuration, even in a case where heat conduction between the temperature sensor 3 and the surroundings of the temperature sensor cannot be ignored, the steady state and transient response of the temperature T2 of the temperature estimation site can be estimated using only the correction value T1cr of the sensor temperature calculated based on the detected value T1det of the sensor temperature, and the correction values T1crnow, T1crold of the sensor temperature before and after the time step ΔT, and the thermal time constant τ. Since the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1 is taken into account, the temperature can be estimated with high precision even if there is a distance between the temperature estimation site 11 and the temperature sensor 3. Therefore, even if the temperature sensor 3 cannot be disposed in the vicinity of the temperature estimation site 11, the estimation precision can be maintained. Therefore, the installation position of the temperature sensor 3 is not limited by the degree of heat conduction from the temperature sensor 3 to the surroundings and the distance between the temperature estimation site 11 and the temperature sensor 3, and the degree of freedom of the installation position can be improved.

[0115] In addition, as with Embodiment 1, since the heat generation amount is not estimated using information other than the detected value of the sensor temperature, such as the current value, and the like, a temperature estimation error does not occur due to an estimation error of the heat generation amount caused by various deviation factors such as manufacturing deviation, secular change, condition change, and the like, and an estimation error of the heat generation amount caused by unexpected heat generation such as short circuit. Therefore, even in a case where variation in the heat generation amount occurs due to various deviation factors such as manufacturing deviation, secular change, condition change, and the like, and unexpected heat generation such as short circuit occurs, the temperature can be estimated with high precision based on the detected value T1det of the sensor temperature that exhibits variation in the heat generation amount, and thus the reliability of the system can be improved.

[0116] Since the detected value of the sensor temperature is used, other information such as the current value is not required, the number of input signals input to the control device 30 can be reduced, and simplification of the device can be achieved. In addition, since the detected value of the sensor temperature is used for the operation, a complex operation using a plurality of parameters such as the current value is not required, and the operation processing load can be reduced.

[0117] In the present embodiment, the temperature estimation unit 33 calculates the estimated temperature T2e of the temperature estimation site using the following equation corresponding to Equation (8), based on the detected value T1crnow of the current sensor temperature and the detected value T1crold of the sensor temperature before the time step ΔT.

[0118] T2e = T1crnow + τ × (T1crnow - T1crold) / ΔT... (9)

[0119] According to formula (9), in the steady state, (T1crnow - T1crold) = 0, and T2e = T1crnow. Thus, in the steady state, it is possible to suppress a situation in which a stable deviation occurs between the estimated temperature T2e of the temperature estimation site and the actual temperature. In addition, in the calculation of formula (9), a response delay caused by the thermal time constant τ is taken into account. Specifically, the correction value T1cr of the sensor temperature is subjected to first-order progression processing corresponding to the thermal time constant τ, and the estimated temperature T2e of the temperature estimation site is calculated.

[0120] Thus, even in a case in which a variation in the amount of heat generation caused by various deviation factors occurs, or a case in which unexpected heat generation such as short circuit occurs, it is possible to estimate the estimated temperature T2e of the temperature estimation site with high accuracy in the transient state and the steady state by the variation (T1crnow - T1crold) in the correction value of the sensor temperature between the time steps ΔT and the thermal time constant τ.

[0121] The temperature estimation section 33 calculates the correction value T1crnow of the current sensor temperature using the following formula and based on the detected value T1detnow of the current sensor temperature.

[0122] T1crnow = T1detnow + (T1detnow - T0) x α... (10)

[0123] The temperature estimation section 33 stores the detected value T1crnow of the sensor temperature at each time detected in the storage device 91 such as a RAM. Also, the temperature estimation section 33 reads the detected value T1crold of the sensor temperature calculated by advancing the current by the time step ΔT from the storage device 91.

[0124] The ambient temperature T0 of the temperature sensor is set in advance to a prescribed temperature. For example, the ambient temperature T0 can be set to a temperature (for example, 25°C) of a standard state of the surrounding gas or liquid. When there is a liquid refrigerant around, the ambient temperature T0 can be set to a rated temperature of the cooling mechanism. Alternatively, the ambient temperature T0 can be set to a temperature detected by a temperature sensor that measures the temperature of the surrounding gas or liquid.

[0125] In addition, in formula (10), α is a coefficient. The coefficient α is set to a value calculated based on the thermal resistance R10 between the sensor section 4 and the ambient of the temperature sensor and the thermal resistance R21 between the temperature estimation site 11 and the sensor section 4 by the following formula.

[0126] α = R21 / R10... (11)

[0127] Alternatively, the coefficient α can also be set to the following expression obtained after using the modified form (6), and a value calculated based on the ambient temperature T0st of the temperature sensor in the steady state, the sensor temperature T1st, and the temperature T2st of the temperature estimation site. The steady-state temperatures are obtained through experiments.

[0128] α = (T2st - T1st) / (T1st - T0st) (12)

[0129] <Setting of thermal time constant τ>

[0130] As with Embodiment 1, the thermal time constant τ is set to a value calculated using the heat capacity C of the temperature sensor and the thermal resistance R21 between the temperature estimation site 11 and the sensor portion 4, and by Expression (1). Alternatively, the thermal time constant τ can be set to a value calculated based on the measured data at the time of temperature rise.

[0131] <Overheat protection>

[0132] As with Embodiment 1, according to the temperature estimation using the thermal time constant τ, by the physical phenomenon that the actual thermal time constant at the time of abnormal heat generation such as short circuit is smaller than the thermal time constant τ used by the temperature estimation portion 33, even if both the abnormal heat generation and the normal heat generation are considered, it is possible to set the determination value to a temperature corresponding to the heat resistance temperature of the device, it is possible to maintain the reliability of the device, and it is possible to suppress the device from becoming large.

[0133] <Setting of larger thermal time constant τ>

[0134] As with Embodiment 1, it is possible to set the larger of the value of the thermal time constant calculated by Expression (1) and the value of the thermal time constant calculated based on the measured data at the time of temperature rise as the thermal time constant τ. In addition, as a matter of design for adjusting the temperature margin of the device, a value obtained by multiplying the thermal time constant calculated according to Expression (1) or the measured data by a coefficient of about 0.5 to 2 is set as the thermal time constant τ. Furthermore, when the heat capacity C has temperature dependence or the like and the thermal time constant changes depending on the temperature or the like operating state, the temperature estimation portion 33 can change the thermal time constant τ depending on the operating state.

[0135] <Estimation behavior>

[0136] Figure 5An example of the estimated behavior of the temperature is shown in FIG. 10. For the experiment, a temperature sensor is mounted on the temperature estimation site 11, and the actual value of the temperature T2 of the temperature estimation site is detected. Before time t01, the temperature estimation object 10 is in a stable state in a state without heat generation, the detected value T1det of the sensor temperature and the actual value of the temperature T2 of the temperature estimation site coincide with the actual value of the ambient temperature T0 of the temperature sensor. At this time, according to the equation (10), the deviation between the detected value T1det of the sensor temperature and the ambient temperature T0 of the temperature sensor is 0, and the correction value T1cr of the sensor temperature coincides with the detected value T1det of the sensor temperature. Therefore, according to the equation (9), the estimated temperature T2e of the temperature estimation site coincides with the detected value T1det of the sensor temperature, and the temperature can be estimated with high accuracy.

[0137] At time t01, the amount of heat generation of the temperature estimation object 10 gradually increases. After time t01, the actual value of the temperature T2 of the temperature estimation site increases with a delay. The detected value T1det of the sensor temperature increases with a delay with respect to the actual value of the temperature T2 of the temperature estimation site with a thermal time constant.

[0138] When the detected value T1det of the sensor temperature starts to increase from the ambient temperature T0 of the temperature sensor, according to the equation (10), the correction value T1cr of the sensor temperature starts to increase from the detected value T1det of the sensor temperature by an amount corresponding to the deviation between the detected value T1det of the sensor temperature and the ambient temperature T0. Since the estimated temperature T2e of the temperature estimation site is calculated by performing the first-order progression processing corresponding to the thermal time constant τ on the correction value T1cr of the sensor temperature, the estimated temperature T2e of the temperature estimation site approaches the actual value of the temperature T2 of the temperature estimation site. In Figure 5 In the example of FIG. 10, since the temperature rapidly rises or a large thermal time constant τ is set, the thermal time constant τ becomes larger than the actual thermal time constant. Therefore, the estimated temperature T2e of the temperature estimation site advances in phase compared to the actual value of the temperature T2 of the temperature estimation site, and becomes larger than the actual value of the temperature T2 of the temperature estimation site. Therefore, the temperature rise of the temperature estimation site can be detected as early as possible, and the overheat protection can be performed as early as possible. In addition, if the thermal time constant τ is made to coincide with the actual thermal time constant, the estimated temperature T2e can coincide with the actual value.

[0139] On the other hand, when the actual value of the temperature T2 at the temperature estimation point is close to the steady state, as explained using equations (6) and (7), the correction value T1cr of the sensor temperature, which takes into account the heat flow in the steady state, is consistent with the actual value of the temperature T2 at the temperature estimation point. Therefore, the estimated temperature T2e of the temperature estimation point, which is consistent with the correction value T1cr of the sensor temperature in the steady state, is consistent with the actual value of the temperature T2 at the temperature estimation point. Therefore, the heat conduction between the temperature sensor 3 and the surrounding area of ​​the temperature sensor cannot be ignored, and even when T1det ≠ T2 in the steady state, the temperature of the temperature estimation point in the steady state can be estimated with high accuracy based on the detected value T1det of the sensor temperature.

[0140] <Control Methods>

[0141] Figure 6 The flowchart illustrates the control method of this embodiment. In step S11, as described above, a time constant setting step is performed, in which the thermal time constant τ is set to the value calculated according to equation (1). The time constant setting step can be performed by the temperature estimation unit 33 or pre-executed by the designer.

[0142] Alternatively, in step S11, as described above, a time constant setting step can be performed, in which the thermal time constant τ is set to a value calculated based on the measurement data during temperature rise. The time constant setting step can be performed by the temperature estimation unit 33, or it can be performed in advance by the designer.

[0143] In step S12, as described above, a coefficient setting step is performed, in which the coefficient α is set to the value calculated according to equation (11). The coefficient setting step can be performed by the temperature estimation unit 33 or by the designer in advance.

[0144] Alternatively, in step S12, as described above, a coefficient setting step can also be performed, in which the coefficient α is set to a value calculated using equation (12) based on the ambient temperature T0st, sensor temperature T1st, and temperature T2st of the temperature estimation part under steady-state conditions. The coefficient setting step can be performed by the temperature estimation unit 33 or pre-executed by the designer.

[0145] In step S13, as described above, a sensor temperature detection step is performed. In this sensor temperature detection step, the sensor temperature detection unit 32 detects the sensor temperature T1 based on the output signal of the temperature sensor 3.

[0146] In step S14, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation section based on the correction value T1crnow of the current sensor temperature calculated based on the detected value T1detnow of the current sensor temperature, the correction value T1crold of the sensor temperature before the time step ΔT, and the thermal time constant τ from the temperature of the temperature estimation section T2 to the sensor temperature T1, as described above. In the present embodiment, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation section based on the correction value T1crnow of the current sensor temperature and the correction value T1crold of the sensor temperature before the time step ΔT using Equation (9). In addition, the temperature estimation section 33 calculates the correction value T1crnow of the current sensor temperature based on the detected value T1detnow of the current sensor temperature using Equation (10).

[0147] In step S15, a device control step is executed in which the device control section 31 controls the power consumption of the temperature estimation target object 10, as described above. The device control section 31 suppresses the heat generation of the temperature estimation target object 10 based on the estimated temperature T2e of the temperature estimation section estimated by the temperature estimation section 33.

[0148] Steps S13 to S15 are repeatedly executed for each operation cycle. On the other hand, steps S11 and S12 are executed at each operation cycle, design stage, or temperature rise.

[0149] 3. Embodiment 3

[0150] The control device 30 related to Embodiment 3 will be described. Explanation of the same structural parts as those of Embodiment 1 or 2 will be omitted. The basic structure of the control device 30 related to the present embodiment is the same as that of Embodiment 1 or 2, but the control device 30 controls a rotary electric machine, and the temperature estimation target object 10 is a rotary electric machine, which is different from Embodiment 1 or 2. Figure 7 is a schematic structural view of a rotary electric machine 50, an inverter 51, the control device 30, and the like.

[0151] 3-1. Rotary Electric Machine 50

[0152] Figure 8 A cross-sectional view of the rotary electric machine 50 cut on a plane passing through the rotational axis is shown. The rotary electric machine 50 has a cylindrical stator 100 and a cylindrical rotor 200 disposed on the radially inner side of the stator 100 and rotatably supported by bearings 204, 205. In the present embodiment, the rotary electric machine 50 is a permanent magnet synchronous motor, and a coil 102 is wound around the stator 100, and a permanent magnet 202 is provided on the rotor 200. The rotary electric machine 50 is configured as an oil-cooled type.

[0153] The stator 100 includes a stator core 101 in which annular plate-shaped electromagnetic steel sheets are stacked in the axial direction, and coils 102 wound around the teeth of the stator core 101. A plurality of teeth are provided at uniform intervals in the circumferential direction. The coils 102 have coil portions 104 (core-internal coil portions 104) disposed in the stator core 101 (in slots) and coil end portions 103 protruding from the stator core 101 to both sides in the axial direction. As the coils 102, a plurality of phase coils (in this example, three-phase coils Cu, Cv, and Cw of U phase, V phase, and W phase) are provided, and the end portions of the respective phase coils are connected to the inverter 51. In addition, a plurality of sets (for example, two sets) of three-phase coils can be provided.

[0154] The temperature estimation target object 10 is set to the coils 102, and the temperature sensor 3 is attached to the coils 102. In this embodiment, the temperature sensor 3 is attached to the coil end portions 103 on one side in the axial direction. In addition, the temperature sensor 3 can be attached to a portion of the coils 102 other than the coil end portions 103.

[0155] The rotor 200 includes a rotor core 201 in which annular plate-shaped electromagnetic steel sheets are stacked in the axial direction, permanent magnets 202 attached to the respective slots of the rotor core 201, and a rotation shaft 203 fixed to the inner circumferential surface of the rotor core 201. In addition, the permanent magnets 202 can be fixed to the outer circumferential surface of the rotor core 201. The rotation shaft 203 includes a rotation sensor 53 (not shown in FIG. 1) for detecting the rotation angle of the rotor 200. The rotation sensor 53 uses a resolver, an encoder, an MR sensor, or the like. The output signal of the rotation sensor 53 is input to the control device 30. Figure 8

[0156] The stator 100 and the rotor 200 are housed in a housing and sealed in a liquid-tight state. The housing includes a first housing 300 that is a bottomed cylindrical shape having a deep bottom, and a second housing 301 that is a bottomed cylindrical shape having a shallow bottom, which plugs the opening portion of the first housing 300. The stator 100 (the stator core 101) is fixed to the inner circumferential surface of the peripheral wall of the first housing 300. The bottom wall of the first housing 300 and the bottom wall of the second housing 301 are provided with through-holes through which the rotation shaft 203 penetrates, the inner circumferential surface of the through-hole of the bottom wall of the first housing 300 rotatably supports one side in the axial direction of the rotation shaft 203 via a first bearing 204, and the inner circumferential surface of the through-hole of the bottom wall of the second housing 301 rotatably supports the other side in the axial direction of the rotation shaft 203 via a second bearing 205. The first bearing 204 and the second bearing 205 are seal bearings, and are configured so as not to leak the cooling oil in the housing to the outside.

[0157] ​The housing is provided with a refrigerant supply port 401 for supplying cooling oil from an external refrigerant circulation cooling device into the housing, and a refrigerant discharge port 402 for discharging cooling oil from the housing into the refrigerant circulation cooling device. The cooling oil supplied into the housing is discharged from the housing after cooling the stator 100 and rotor 200. The refrigerant circulation cooling device cools the refrigerant (in this embodiment, cooling oil) used to cool the rotating motor 50 via a radiator or the like, and circulates it.

[0158] The cooling oil is agitated by the rotation of rotor 200 and supplied to various parts of rotor 100 and rotor 200. Cooling oil is also supplied around temperature sensor 3, and the ambient temperature T0 of the temperature sensor becomes the temperature of the cooling oil. Therefore, the ambient temperature T0 of the temperature sensor can be set to the rated temperature of the refrigerant circulation cooling system, or it can be set to the temperature detected by the temperature sensor installed in the refrigerant circulation cooling system. Alternatively, in the case of air cooling, the ambient temperature T0 of temperature sensor 3 is the temperature of the air.

[0159] 3-2. Inverter 51

[0160] like Figure 9 As shown, the inverter 51 is provided with three sets of series circuits (legs) corresponding to each of the three phases. Each series circuit is connected in series with a positive-side switching element SP connected to the positive side of the DC power supply 52 and a negative-side switching element SN connected to the negative side of the DC power supply 52. ​​Moreover, the connection point of the two switching elements in the series circuit of each phase is connected to the coil of the corresponding phase.

[0161] For the switching elements, FETs (Field Effect Transistors) with diodes connected in reverse parallel, IGBTs (Insulated Gate Bipolar Transistors) with diodes connected in reverse parallel, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), and bipolar transistors with diodes connected in reverse parallel are used. The gate terminals of each switching element are connected to the control device 30 via gate drive circuits, etc. Each switching element is turned on or off by a switching signal output from the control device 30.

[0162] The direct-current power supply 52 outputs a direct-current voltage Vdc to the inverter 51. As the direct-current power supply 52, any device that outputs a direct-current voltage, such as a battery, a DC-DC converter, a diode rectifier, a PWM rectifier, and the like, can be used. The direct-current power supply 52 is provided with a voltage sensor 55 that detects the direct-current voltage Vdc of the direct-current power supply 52, and an output signal of the voltage sensor 55 is input to the control device 30.

[0163] A current sensor 54 that detects a current flowing through each phase coil is provided. The current sensor 54 is provided on an electric wire that connects a series circuit of two switching elements of each phase and each phase coil. An output signal of the current sensor 54 is input to the control device 30. In addition, the current sensor 54 can also be provided on the series circuit of the two switching elements of each phase.

[0164] 3-3. Control Device 30

[0165] In the present embodiment, the device control section 31 controls the rotary electric machine 50 via the inverter 51. The rotary sensor 53, the current sensor 54, the voltage sensor 55, the temperature sensor 3, and the like are connected to an input circuit 92, and output signals of these sensors are A / D-converted and input to an arithmetic processing device 90. An electric load such as a gate drive circuit that performs on-off driving of the switching elements is connected to an output circuit 93.

[0166] The device control section 31 controls an applied voltage applied to the three-phase coils of the rotary electric machine 50 based on detection signals of each sensor, and controls a torque of the rotary electric machine 50. For example, the device control section 31 calculates a current command value based on a torque command value, a rotational speed detected by the rotary sensor 53, and a direct-current voltage Vdc detected by the voltage sensor 55. The device control section 31 changes a voltage command value so that a current detection value detected by the current sensor 54 approaches the current command value. The device control section 31 performs on-off driving of the switching elements based on the voltage command value, and applies a voltage to the three-phase coils.

[0167] The device control section 31 suppresses heating of the coils based on the estimated temperature T2e of the temperature estimation site estimated by the temperature estimation section 33. For example, in a case where the estimated temperature T2e of the temperature estimation site exceeds a determination value, the device control section 31 reduces an output torque of the rotary electric machine 50, and reduces power consumption.

[0168] The coil is insulated by resin or the like, and in order to ensure insulation, it is necessary to suppress overheating. Therefore, in the present embodiment, the temperature estimation site 11 is set at a site within the coil at which the temperature is highest or at which overheating protection is required. The site at which overheating protection is required is set at a site within the coil at which cooling is not easy and the temperature is particularly likely to rise. For example, the temperature estimation site is set at the inner core coil portion 104 (for example, the axial center portion) disposed within the stator core. The temperature sensor 3 is not easily installed directly to the inner core coil portion 104 disposed within the stator core. Therefore, the temperature sensor 3 is installed to the coil end portion 103 away from the inner core coil portion 104. Furthermore, since resin for insulation and fixation exists between the temperature sensor 3 and the coil, thermal resistance is generated. Therefore, a deviation occurs between the detected value T1det of the sensor temperature and the temperature T2 of the temperature estimation site, and it is necessary to estimate the temperature with high precision.

[0169] In a case where the surface of the temperature sensor 3 at the contact portion with the coil is thermally insulated from the surrounding refrigerant by a thermal insulation material or the like, as with Embodiment 1, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site on the basis of the detected value T1detnow of the current sensor temperature, the detected value T1detold of the sensor temperature before the time step ΔT, the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1.

[0170] On the other hand, in a case where the heat conduction between the temperature sensor 3 and the surroundings of the temperature sensor cannot be ignored, as with Embodiment 2, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site on the basis of the correction value T1crnow of the current sensor temperature calculated on the basis of the detected value T1detnow of the current sensor temperature, the correction value T1crold of the sensor temperature before the time step ΔT, and the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1.

[0171] In either method, each of the set values of the thermal time constant τ, the coefficient α, the heat capacity C, the thermal resistances R21, R10, and the determination value is set on the basis of the rotating electric machine 50. The estimation method itself is the same as in Embodiment 1 or 2, and therefore the description is omitted.

[0172] 4. Embodiment 4

[0173] The control device 30 related to Embodiment 4 is described. The description of the same structural portions as in the above-described Embodiment 3 is omitted. The basic structure of the control device 30 related to the present embodiment is the same as in Embodiment 3, but differs from Embodiment 3 in that the temperature estimation object 10 is a power conversion device (in the present example, the inverter 51). Figure 10 is a schematic structural view of the rotating electric machine 50, the inverter 51, the control device 30, and the like.

[0174] The temperature estimation target 10 is provided as the inverter 51, and the temperature sensor 3 is attached to the inverter 51. In the present embodiment, the temperature estimation site 11 is set at a site in the inverter 51 at which the temperature is highest or at which overheat protection is required. For example, the temperature estimation site 11 is provided as a switching element. However, since the temperature sensor 3 is not easily attached directly to the switching element, the temperature sensor 3 is attached to a position away from the switching element. Therefore, a deviation occurs between the detected value T1det of the sensor temperature and the temperature T2 of the temperature estimation site, and it is required to estimate the temperature with high accuracy.

[0175] As with the rotating electric machine 50, the inverter 51 is also cooled by a liquid of cooling oil or cooling water or air.

[0176] In a case where the surface of the temperature sensor 3 that contacts the inverter 51 is thermally insulated from the surrounding refrigerant by a thermal insulation material or the like, as with Embodiment 1, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site on the basis of the detected value T1detnow of the current sensor temperature, the detected value T1detold of the sensor temperature before the time step ΔT, and the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1.

[0177] On the other hand, in a case where the heat conduction between the temperature sensor 3 and the surroundings of the temperature sensor cannot be ignored, as with Embodiment 2, the temperature estimation section 33 calculates the estimated temperature T2e of the temperature estimation site on the basis of the correction value T1crnow of the current sensor temperature calculated on the basis of the detected value T1detnow of the current sensor temperature, the correction value T1crold of the sensor temperature before the time step ΔT, and the thermal time constant τ from the temperature T2 of the temperature estimation site to the sensor temperature T1.

[0178] In either method, each of the set values of the thermal time constant τ, the coefficient α, the heat capacity C, the thermal resistances R21, R10, and the determination value is set on the basis of the inverter 51. The estimation method itself is the same as in Embodiment 1 or 2, and thus the description is omitted.

[0179] The device control section 31 suppresses the heat generation of the inverter 51 on the basis of the estimated temperature T2e of the temperature estimation site estimated by the temperature estimation section 33. For example, in a case where the estimated temperature T2e of the temperature estimation site exceeds the determination value, the device control section 31 reduces the output torque of the rotating electric machine 50, and reduces the power consumption of the inverter 51.

[0180]

[0181] ​(1) In each of the above-described embodiments, the case where one temperature estimation site 11 is set has been described as an example. However, the temperature estimation site can be set to a plurality of sites, the estimation processing of each of the above-described embodiments can be executed for each temperature estimation site, and the temperature of each temperature estimation site can be estimated.

[0182] (2) In each of the above-described embodiments, the case where one temperature sensor 3 is provided and the temperature of one temperature estimation site is estimated by one temperature sensor 3 has been described as an example. However, a plurality of temperature sensors 3 can be provided, and the temperature of one or a plurality of temperature estimation sites can be estimated from each temperature sensor 3.

[0183] (3) In each of the above-described embodiments, the case where one temperature estimation target object 10 is provided has been described as an example. The temperature estimation target object 10 can be provided as a plurality of different objects, a temperature sensor 3 can be attached to each temperature estimation target object 10, and the temperature of a temperature estimation site set in the inside of each temperature estimation target object 10 can be estimated by each temperature sensor 3.

[0184] (4) In each of the above-described embodiments 3, the case where the temperature estimation site 11 is set to the coil of the rotary electric machine 50 has been described as an example. However, the temperature estimation site 11 can be set to a portion other than the coil of the rotary electric machine 50 (for example, a permanent magnet of a rotor).

[0185] (5) In each of the above-described embodiments 4, the case where the temperature estimation target object 10 is set to the inverter 51 has been described as an example. However, the temperature estimation target object 10 can be set to various power conversion devices other than the inverter 51 (for example, a DC-DC converter).

[0186] Although various exemplary embodiments and examples are described in the present application, the various features, modes, and functions described in one or more embodiments are not limited to the application of the specific embodiments, and can be applied to the embodiments individually or in various combinations. Therefore, it can be considered that an infinite number of modifications not exemplified are also included in the technical scope disclosed in the present application specification. For example, a case where at least one constituent element is modified, added, or omitted, and a case where at least one constituent element is extracted and combined with the constituent elements of other embodiments are included.

[0187] Explanation of Reference Signs

[0188] 3 Temperature sensor

[0189] 4 Sensor portion

[0190] 10 Temperature estimation target object

[0191] 11 Temperature estimation site

[0192] 30 control device

[0193] 31 device control section

[0194] 32 sensor temperature detection section

[0195] 33 temperature estimation section

[0196] 50 rotating electric machine

[0197] 51 inverter (power conversion device)

[0198] C heat capacity of temperature sensor

[0199] R10 thermal resistance between sensor section and surroundings of temperature sensor

[0200] R21 thermal resistance between temperature estimation section and sensor section

[0201] TO ambient temperature of temperature sensor

[0202] T1 sensor temperature

[0203] T1cr correction value of sensor temperature

[0204] T1crnow correction value of current sensor temperature

[0205] T1crold correction value of sensor temperature before time step

[0206] T1det detected value of sensor temperature

[0207] T1detnow detected value of current sensor temperature

[0208] T1detold detected value of sensor temperature before time step

[0209] T2 temperature of temperature estimation section

[0210] T2e estimated temperature of temperature estimation section

[0211] ΔT time step

[0212] α coefficient

[0213] τ thermal time constant

Claims

1. A control device, characterized in that, include: The sensor temperature detection unit detects the sensor temperature based on the output signal of a temperature sensor installed on the object to be temperature predicted. as well as The temperature estimation unit calculates the estimated temperature of the temperature estimation location based on the current sensor temperature detection value or a correction value of the current sensor temperature calculated based on the current sensor temperature detection value, the sensor temperature detection value or the correction value of the sensor temperature before the time step, and the thermal time constant from the temperature of the temperature estimation location set inside the temperature estimation object to the sensor temperature. The current sensor temperature detection value or the current sensor temperature correction value is set as T1now, the sensor temperature detection value or the sensor temperature correction value before the time step is set as T1old, the thermal time constant is set as τ, the time step is set as ΔT, and the predicted temperature of the temperature prediction part is set as T2e. The temperature prediction part uses the calculation formula T2e=T1now+τ×(T1now-T1old) / ΔT to calculate the predicted temperature of the temperature prediction part.

2. The control device as described in claim 1, characterized in that, The ambient temperature of the temperature sensor is set as T0, the detected temperature value of the sensor is set as T1det, the coefficient is set as α, and the correction value of the sensor temperature is set as T1cr. The temperature estimation unit calculates the correction value of the sensor temperature using the formula T1cr=T1det+(T1det-T0)×α.

3. The control device as described in claim 2, characterized in that, The thermal resistance between the sensor part of the temperature sensor and the surrounding area of ​​the temperature sensor is set to R10, and the thermal resistance between the temperature estimation part and the sensor part is set to R21. The coefficient is set to the value calculated by the formula α = R21 / R10.

4. The control device as described in claim 2, characterized in that, The ambient temperature of the temperature sensor in a steady state is set as T0st, the sensor temperature is set as T1st, and the temperature of the temperature estimation part is set as T2st. The coefficient is set as the value calculated by the formula α = (T2st - T1st) / (T1st - T0st).

5. The control device as described in any one of claims 1 to 4, characterized in that, The thermal time constant is set as τ, the thermal capacity of the temperature sensor is set as C, and the thermal resistance between the temperature estimation part and the sensor part of the temperature sensor is set as R21. The thermal time constant is set as the value calculated by the formula τ = C × R21.

6. The control device as described in any one of claims 1 to 4, characterized in that, The thermal time constant is set to a value calculated based on measurement data during temperature rise.

7. The control device as described in any one of claims 1 to 4, characterized in that, It includes a heat suppression unit that suppresses the heating of the object whose temperature is being predicted, based on the predicted temperature from the temperature prediction unit. The thermal time constant is set as τ, the thermal capacity of the temperature sensor is set as C, the thermal resistance between the temperature estimation part and the sensor part of the temperature sensor is set as R21, and a value greater than either the value of the thermal time constant calculated by the formula τ=C×R21 or the value of the thermal time constant calculated based on the measurement data when the temperature rises is set as the thermal time constant.

8. The control device as described in any one of claims 1 to 4, characterized in that, It includes a device control unit that controls the power consumption of the object being measured for temperature. The device control unit controls the heating of the object whose temperature is being predicted based on the predicted temperature from the temperature prediction unit.

9. The control device as described in any one of claims 1 to 4, characterized in that, It includes a device control unit that controls the rotating motor. The temperature estimation unit calculates the estimated temperature of the temperature estimation part located inside the temperature estimation object, which is located in the rotary motor. The device control unit suppresses the heating of the rotating motor based on the predicted temperature from the temperature prediction unit.

10. The control device according to any one of claims 1 to 4, characterized in that, This includes a device control unit that controls the power conversion device. The temperature estimation unit calculates the estimated temperature of the temperature estimation part located inside the temperature estimation object, which is located in the power conversion device. The device control unit suppresses the heating of the power conversion device based on the predicted temperature from the temperature prediction unit.

11. A control method, characterized in that, Includes the following steps: The sensor temperature detection step involves detecting the sensor temperature based on the output signal of a temperature sensor installed on the object to be temperature predicted. as well as The temperature estimation step involves calculating the estimated temperature of the temperature estimation location based on the current sensor temperature detection value or a corrected value calculated based on the current sensor temperature detection value, the sensor temperature detection value or the corrected value before the time step, and the thermal time constant from the temperature of the temperature estimation location set inside the object to be estimated to the sensor temperature. In the temperature estimation step, the ambient temperature of the temperature sensor is set as T0, the detected temperature value of the sensor is set as T1det, the coefficient is set as α, and the correction value of the sensor temperature is set as T1cr. The correction value of the sensor temperature is calculated using the formula T1cr=T1det+(T1det-T0)×α.

12. The control method as described in claim 11, characterized in that, The method includes a coefficient setting step, in which the thermal resistance between the sensor part of the temperature sensor and the surrounding area of ​​the temperature sensor is set to R10, the thermal resistance between the temperature estimation part and the sensor part is set to R21, and the coefficient is set to the value calculated using the formula α = R21 / R10.

13. The control method as described in claim 11, characterized in that, The method includes a coefficient setting step, in which the ambient temperature of the temperature sensor in a stable state is set as T0st, the sensor temperature is set as T1st, the temperature of the temperature estimation part is set as T2st, and the coefficient is set as the value calculated by the formula α = (T2st - T1st) / (T1st - T0st).

14. The control method according to any one of claims 11 to 13, characterized in that, The method includes a time constant setting step, in which the thermal time constant is set to τ, the thermal capacity of the temperature sensor is set to C, the thermal resistance between the temperature estimation part and the sensor part of the temperature sensor is set to R21, and the thermal time constant is set to the value calculated by the formula τ = C × R21.

15. The control method according to any one of claims 11 to 13, characterized in that, The method includes a time constant setting step, in which the thermal time constant is set to a value calculated based on the measurement data during temperature rise.

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