Temperature Estimation System

Abstract

To provide a temperature estimation system that, based on the temperature of a first object to be monitored detected by a temperature sensor, can accurately estimate the temperature of a second object to be monitored different from the first object to be monitored.SOLUTION: A control unit 20 of a temperature estimation system 1 derives the quantity of heat transferred from an intelligent power module (IPM) 11 being a first object to be monitored to a cooling route 13a of a cooling device 13 based on a first temperature estimation value being a temperature estimation value of the IPM 11 when assuming that the quantity of heat transferred from the IPM 11 to the cooling route 13a of the cooling device 13 is zero, and the temperature of the IPM 11 detected by a temperature sensor 14, and estimates a second temperature estimation value being the temperature of a capacitor 12 being a second object to be monitored based on the derived quantity of heat transferred from the IPM 11 to the cooling route 13a, and a calorific value according to the current operating state of the capacitor 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a temperature estimation system. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have been gaining momentum as a concrete measure against global climate change. As part of these efforts, research and development is being conducted on electric vehicles (EVs) and hybrid EVs (HEVs), which use motors as their drive source, in order to reduce CO2 emissions and improve energy efficiency from automobiles and other vehicles.

[0003] Some systems equipped with multiple electronic components monitor the temperature of each electronic component and, if the temperature of any electronic component exceeds a predetermined temperature, limit the output to prevent the electronic components from overheating.

[0004] For example, Patent Document 1 listed below discloses a technology in which the temperature of the element among multiple switching elements with the smallest "grace temperature," calculated by subtracting the current temperature of the element from the output limit temperature set for each element, is estimated as the "restriction target temperature," and output restriction of the power conversion circuit is initiated when the restriction target temperature reaches the output limit temperature of that element.

[0005] Furthermore, Patent Document 2 listed below discloses a technology in which the capacitor temperature, which is the temperature of a capacitor connected in parallel to a battery, is estimated based on the capacitor current, which is the current flowing through the capacitor, and the current flowing from the battery to an inverter is limited based on the capacitor temperature. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-169260 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-148695 Summary of the Invention [Problem to be solved by the invention]

[0007] If a temperature sensor is provided for each monitored object whose temperature is to be monitored, a large number of temperature sensors would be required, which may complicate the system configuration. Therefore, it is conceivable to estimate the temperature of a second monitored object, which is different from the first monitored object, based on the temperature of the first monitored object detected by the temperature sensor. However, in the prior art, there is room for improvement in terms of accurately estimating the temperature of the second monitored object.

[0008] The present invention provides a temperature estimation system that enables accurate estimation of the temperature of a second monitoring object different from a first monitoring object based on the temperature of the first monitoring object detected by a temperature sensor. [Means for solving the problem]

[0009] One aspect of the present invention is a first monitored object and a second monitored object, each of which is composed of one or more electronic components; a cooling device having a cooling path through which a refrigerant flows to cool the first monitored object and the second monitored object; a temperature sensor for detecting a temperature of the first monitoring object; a control device that estimates the temperature of the second monitored object based on the temperature of the first monitored object detected by the temperature sensor; A temperature estimation system comprising: the first monitored object and the second monitored object are thermally connected; The control device deriving the amount of heat transferred from the first monitored object to the cooling path based on a first temperature estimation value, which is a temperature estimation value of the first monitored object when it is assumed that the amount of heat transferred from the first monitored object to the cooling path is zero, and the temperature of the first monitored object; A second temperature estimation value, which is the temperature of the second monitored object, is estimated based on the amount of heat transferred from the first monitored object to the cooling path and the amount of heat generated according to the current operating state of the second monitored object. death , further estimating the second temperature estimated value based on the amount of heat transferred from the first monitored object to the second monitored object; A temperature estimation system. [Effects of the Invention]

[0010] According to the present invention, a temperature estimation system can be provided that enables accurate estimation of the temperature of a second monitored object, which is different from a first monitored object, based on the temperature of the first monitored object detected by a temperature sensor. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a temperature estimation system 1 according to an embodiment of the present invention. [Figure 2] 2 is a diagram illustrating an example of an electrical or thermal connection relationship between an IPM 11, a condenser 12, and a cooling device 13 in a temperature estimation system 1. FIG. [Figure 3] 10 is a diagram illustrating an example of output control of an IPM 11 based on the result of estimation of the temperature of a capacitor 12 by a control device 20 of the temperature estimation system 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a temperature estimation system of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the following, identical or similar elements will be denoted by identical or similar reference numerals, and their description may be omitted or simplified as appropriate.

[0013] <Temperature estimation system> The temperature estimation system of this embodiment is a system that can estimate the temperature of a second monitoring object different from the first monitoring object based on the temperature of the first monitoring object detected by a temperature sensor. This makes it possible to acquire the temperature of the second monitoring object without providing a temperature sensor to detect the temperature of the second monitoring object, thereby simplifying the configuration.

[0014] Here, the first monitored object and the second monitored object may each be an object that is composed of one or more electronic components and that may generate heat when operating (in other words, when power is supplied). The first monitored object and the second monitored object are not particularly limited, but in this embodiment, an example will be described in which an IPM (Intelligent Power Module) is the first monitored object and a capacitor connected to the output side of the IPM, which is the first monitored object, is the second monitored object.

[0015] As shown in Fig. 1, the temperature estimation system 1 of this embodiment includes a power conversion device 10 electrically connected to each of a voltage / current source PS and a load EL, and a control device 20 that performs overall control of the temperature estimation system 1. In this embodiment, the temperature estimation system 1 is assumed to be mounted on an electric vehicle (not shown) that has a motor as a drive source, such as an electric vehicle or a hybrid electric vehicle. Hereinafter, the electric vehicle on which the temperature estimation system 1 is mounted will also be simply referred to as a "vehicle."

[0016] The voltage / current source PS is a voltage / current source configured to be able to output a predetermined power to the power conversion device 10, and is, for example, a battery serving as a power storage device mounted on a vehicle. More specifically, the voltage / current source PS can be a high-voltage battery (a so-called drive battery) configured by connecting a plurality of power storage cells, such as lithium-ion batteries or nickel-metal hydride batteries, in series or series-parallel, and capable of outputting a high voltage of 100 to 200 V. Furthermore, the voltage / current source PS is not limited to such a high-voltage battery, and may also be, for example, a low-voltage battery (a so-called auxiliary battery) capable of outputting a low voltage of about 12 V, a fuel cell, a generator, or the like.

[0017] The load EL is an electrically powered device that operates using power supplied from the power conversion device 10, and may be, for example, a motor that is a drive source for the vehicle (hereinafter also referred to as a "drive motor"), or an inverter that converts the power supplied to the drive motor. Furthermore, the load EL is not limited to such a drive motor or inverter, and may be, for example, a motor that drives a fan, pump, or compressor mounted on the vehicle (e.g., a motor for an air conditioner).

[0018] The power conversion device 10 is a device that generates a predetermined power from power supplied from a voltage / current source PS under the control of a control device 20 and outputs the generated power to a load EL. Specifically, the power conversion device 10 is configured to include an IPM 11, which is an example of a first monitored object, a capacitor 12, which is an example of a second monitored object, a cooling device 13, a temperature sensor 14, a voltage sensor 15, and a current sensor 16. For example, the power conversion device 10 is configured by accommodating the IPM 11, the capacitor 12, the cooling device 13, the temperature sensor 14, the voltage sensor 15, and the current sensor 16 in the same housing.

[0019] The IPM 11 has a plurality of switching elements (not shown) realized by MOSFETs (metal oxide semiconductor field effect transistors), IGBTs (insulated gate bipolar transistors), etc. The IPM 11 generates a predetermined amount of power by switching these switching elements according to the control of the control device 20, and outputs the generated power.

[0020] The capacitor 12 is a capacitor connected to the output side of the IPM 11 (more specifically, between the IPM 11 and the load EL), and can function as a smoothing capacitor that smoothes the power output from the IPM 11.

[0021] 2, the IPM 11 and the capacitor 12 are electrically and thermally connected via a first bus bar 19a and a second bus bar 19b made of a copper plate or the like. The power output from the IPM 11 is smoothed by the capacitor 12 and supplied to the load EL. This allows stable power with small ripple to be supplied to the load EL.

[0022] Cooling device 13 is a device that cools IPM 11 and condenser 12. Specifically, as shown in FIG. 2 , cooling device 13 includes cooling path 13a through which a refrigerant (e.g., a coolant called "LLC") flows to cool IPM 11 and condenser 12, a radiator (not shown) as a heat dissipation device that dissipates heat of the refrigerant flowing through cooling path 13a to the outside air, and a pump (not shown) that circulates the refrigerant within cooling device 13. IPM 11 and condenser 12 are disposed on cooling device 13 in a state capable of heat exchange with the refrigerant flowing through cooling path 13a, and heat from IPM 11 and condenser 12 is transferred to the refrigerant flowing through cooling path 13a and then dissipated to the outside air by the radiator. In this way, cooling device 13 can cool IPM 11 and condenser 12, which may generate heat, thereby suppressing temperature increases.

[0023] Temperature sensor 14 is a sensor that detects the temperature of IPM 11 and outputs a detection signal indicating the detected temperature of IPM 11 to control device 20. Voltage sensor 15 is a sensor that detects the voltage value of power output from IPM 11 (hereinafter also referred to as "output voltage value") and outputs a detection signal indicating the detected output voltage value to control device 20. Current sensor 16 is a sensor that detects the current value of power output from IPM 11 (hereinafter also referred to as "output current value") and outputs a detection signal indicating the detected output current value to control device 20.

[0024] The control device 20 is a computer that controls the entire temperature estimation system 1, and is realized by, for example, an ECU (Electronic Control Unit) that includes a processor (e.g., a so-called CPU) that performs various calculations, a storage device having a non-transitory storage medium (e.g., a flash memory) that stores various information (e.g., data and programs), and an input / output device that controls input and output of data between the inside and outside of the control device 20. Note that the control device 20 may be realized by one ECU, or may be realized by multiple ECUs operating in cooperation with each other.

[0025] The control device 20 controls the power output from the IPM 11 (in other words, the power supplied to the capacitor 12 and the load EL) by, for example, appropriately outputting a predetermined control signal to the power conversion device 10.

[0026] Although details will be described later, in this embodiment, control device 20 estimates the temperature of capacitor 12 based on the temperature of IPM 11 detected by temperature sensor 14, and when the temperature of capacitor 12 exceeds a predetermined threshold, reduces the power output from IPM 11 compared to when the temperature of capacitor 12 does not exceed the threshold. As a result, when it is estimated that the temperature of capacitor 12 will exceed the predetermined threshold (in other words, capacitor 12 will be in a high-temperature state), the power output from IPM 11 (in other words, the power supplied to capacitor 12) is reduced, thereby suppressing a temperature rise in capacitor 12. Therefore, overheating of capacitor 12 can be suppressed, and deterioration or damage to capacitor 12 due to overheating can be suppressed.

[0027] During operation of temperature estimation system 1, a "cooling abnormality" may occur, in which the cooling performance of cooling device 13 is lower than normal due to some factor, such as a refrigerant leak from cooling device 13 or clogging of cooling path 13a. When such a cooling abnormality occurs, the amount of heat transferred from IPM 11 and condenser 12 to cooling path 13a (i.e., the refrigerant of cooling device 13) may change from normal. For this reason, if control device 20 were to estimate the temperature of condenser 12 assuming that the amount of heat transferred from IPM 11 and condenser 12 to cooling path 13a was always constant, it would be difficult to accurately estimate the temperature of condenser 12 when a cooling abnormality occurred.

[0028] Therefore, in this embodiment, the temperature of condenser 12 is estimated by the estimation method described below, which makes it possible to estimate the temperature of condenser 12 while taking into consideration the amount of heat transferred to cooling path 13a from IPM 11 and condenser 12, which may change due to a cooling abnormality. This makes it possible to accurately estimate the temperature of condenser 12 even if a cooling abnormality occurs.

[0029] <Method for estimating the capacitor temperature> For example, when the temperature estimation system 1 is started by turning on the vehicle's ignition power or accessory power, the control device 20 estimates the temperature of the capacitor 12 at a predetermined timing (for example, at a predetermined period) during the startup using the estimation method described below.

[0030] First, the control device 20 calculates the amount of heat Q transferred from the IPM 11 to the cooling path 13a, which may change due to a cooling abnormality. IW Derive the amount of heat Q IW can be derived, for example, by the following equation (1).

[0031]

number

[0032] In the above formula (1), T' IPMis an estimated temperature value of the IPM 11 when it is assumed that the amount of heat transferred from the IPM 11 to the cooling path 13a is zero (in other words, when it is assumed that the cooling effect of the cooling device 13 on the IPM 11 is zero), and is an example of a first estimated temperature value. Hereinafter, the estimated temperature value of the IPM 11 will also be referred to as the "estimated IPM temperature value," and further, the estimated IPM temperature value when it is assumed that the amount of heat transferred from the IPM 11 to the cooling path 13a is zero will be referred to as the "estimated IPM temperature value T' IPM "It is also called ".

[0033] In this embodiment, the estimated IPM temperature value T' IPM It is assumed that an IPM temperature estimation map for deriving the estimated IPM temperature value T' is stored in advance in the control device 20. This IPM temperature estimation map derives the estimated IPM temperature value T' for each output voltage value and output current value that the IPM 11 can take. IPM The controller 20 then refers to the output voltage value detected by the voltage sensor 15, the output current value detected by the current sensor 16, and the IPM temperature estimation map to determine the IPM temperature estimation value T' corresponding to the current output voltage value and output current value of the IPM 11. IPM Derive T' in the above equation (1). IPM The estimated IPM temperature T' according to the current output of the IPM 11 is calculated as follows: IPM is used.

[0034] In the above formula (1), T IPM is the actual measurement value of the temperature of the IPM 11 detected by the temperature sensor 14. Hereinafter, the actual measurement value of the temperature of the IPM 11 detected by the temperature sensor 14 will be referred to as the "IPM temperature T IPM "It is also called ".

[0035] In the above formula (1), R w is the thermal resistance from the IPM 11 to the cooling path 13a. w For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20 as the temperature.

[0036] When no cooling abnormality occurs, the IPM temperature T IPMis the estimated IPM temperature T' IPM Since the heat quantity Q calculated by the above formula (1) is smaller than IW On the other hand, when a cooling abnormality occurs, the IPM temperature T IPM is the estimated IPM temperature T' IPM Therefore, the heat quantity Q calculated by the above formula (1) IW becomes smaller than in the normal state, and can become, for example, approximately zero.

[0037] Next, the control device 20 calculates the amount of heat Q calculated by the above formula (1). IW and the amount of heat generated according to the current operating state of the capacitor 12 (for example, the amount of heat generated Q C ) and estimate the temperature of the capacitor 12.

[0038] In this embodiment, the capacitor 12 is thermally connected to the IPM 11 via the first bus bar 19a and the second bus bar 19b. Therefore, in order to accurately estimate the temperature of the capacitor 12, it is preferable to consider not only the heat generated by the capacitor 12 itself, but also the amount of heat transferred from the IPM 11 to the capacitor 12 via the first bus bar 19a and the second bus bar 19b.

[0039] Therefore, the control device 20 determines the IPM temperature T IPM Based on this, the temperature of the first bus bar 19a (hereinafter referred to as the “first bus bar temperature T Bus1 ") is derived, and the first busbar temperature T Bus1 Based on this, the temperature of the second bus bar 19b (hereinafter referred to as the “second bus bar temperature T Bus2 ") is derived, and the second busbar temperature T Bus2 This allows the temperature of the capacitor 12 to be estimated taking into consideration the amount of heat transferred from the IPM 11 to the capacitor 12 via the first bus bar 19a and the second bus bar 19b, and therefore makes it possible to estimate the temperature of the capacitor 12 with high accuracy.

[0040] Specifically, the first busbar temperature T Bus1 can be derived, for example, by the following equation (2).

[0041]

number

[0042] In the above formula (2), T IPM is the IPM temperature T in the above equation (1). IPM It is the same as T'. Bus1 is, for example, the most recently (i.e., last) derived first busbar temperature T Bus1 It can be expressed as R th1 is the thermal resistance from the IPM 11 to the first bus bar 19a. th1 For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20 as the temperature.

[0043] In the above equation (2), Q I is the heat generation amount of the IPM 11 according to the current output of the IPM 11 (in other words, the current operating state of the IPM 11). I For example, the IPM temperature T IPM and the heat capacity of IPM11, C IPM In this case, the heat capacity C IPM For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20 as the temperature.

[0044] Further, for example, a map that defines the heat generation amount of the IPM 11 for each output voltage value and output current value that the IPM 11 can have is stored in advance in the control device 20, and the control device 20 refers to this map, the output voltage value detected by the voltage sensor 15, and the output current value detected by the current sensor 16, and calculates the heat generation amount Q corresponding to the current output voltage value and output current value of the IPM 11. I may be derived.

[0045] In the above equation (2), Q IW is the heat quantity Q calculated by the above equation (1) IW As mentioned above, when there is no cooling abnormality and normal operation is performed, the heat quantity QIW On the other hand, when a cooling abnormality occurs, the heat quantity Q IW becomes smaller than in the normal state, and can become, for example, approximately zero.

[0046] In the above formula (2), C Bus1 is the heat capacity of the first bus bar 19a. Bus1 For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20 as the temperature.

[0047] In the above formula (2), t is a parameter representing a time, and represents, for example, a time specified by the elapsed time since the temperature estimation system 1 was most recently started. As an example, by substituting a value corresponding to the elapsed time from the most recent start of the temperature estimation system 1 to the present for t in the above formula (2), the current first busbar temperature T Bus1 As another example, by substituting a value corresponding to a time after the present for t in the above equation (2), the future first busbar temperature T Bus1 can also be derived.

[0048] Second busbar temperature T Bus2 can be derived, for example, by the following equation (3).

[0049]

number

[0050] In the above formula (3), T Bus1 is the first busbar temperature T derived from the above equation (2). Bus1 T' Bus2 is, for example, the most recently (i.e., last) derived second busbar temperature T Bus2 It can be expressed as R th2 is the thermal resistance from the first bus bar 19a to the second bus bar 19b. th2 For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20. Bus2is the heat capacity of the second bus bar 19b. Bus2 For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20. t is the same as t in the above equation (2).

[0051] The estimated capacitor temperature T is an estimate of the temperature of the capacitor 12. C is an example of a second temperature estimate value, and can be derived, for example, by the following equation (4).

[0052]

number

[0053] In the above formula (4), T Bus2 is the second busbar temperature T derived from the above equation (3). Bus2 T' C is, for example, the most recently (i.e., last) derived capacitor temperature estimate T C It can be expressed as R th3 is the thermal resistance from the second bus bar 19b to the capacitor 12. th3 For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20 as the temperature.

[0054] In the above equation (4), Q C is the amount of heat generated by the capacitor 12 according to the current operating state of the capacitor 12 (i.e., the power currently supplied to the capacitor 12; in other words, the current output of the IPM 11).

[0055] In this embodiment, the heat generation amount Q CIt is assumed that a capacitor heat generation amount map for deriving the value Q is stored in advance in the control device 20. This capacitor heat generation amount map is a map that specifies the heat generation amount of the capacitor 12 for each output voltage value and output current value that the IPM 11 can have. Then, the control device 20 refers to the output voltage value detected by the voltage sensor 15, the output current value detected by the current sensor 16, and the capacitor heat generation amount map to calculate the heat generation amount of the capacitor 12 corresponding to the current output voltage value and output current value of the IPM 11 as the heat generation amount Q C Q in the above equation (4) C The calorific value Q thus derived is C is used.

[0056] In the above formula (4), C C is the thermal capacity of the capacitor 12. C For example, a predetermined value determined by an experiment or the like is stored in advance in the control device 20. t is the same as t in the above equation (2) and the like.

[0057] In the above equation (4), Q CW is the amount of heat transferred from the condenser 12 to the cooling path 13a, which may change due to a cooling abnormality. CW is the amount of heat transferred from the IPM 11 to the cooling path 13a. IW and the heat generation amount Q of IPM11 I and the heat generation amount Q of the capacitor 12 C More specifically, the amount of heat Q IW and the heat generation amount Q I The ratio of k to the amount of heat Q IW / heat generation amount Q I ), the amount of heat transferred from the condenser 12 to the cooling path 13a is Q CW can be derived, for example, by the following equation (5).

[0058]

number

[0059] As mentioned above, when a cooling abnormality occurs, the amount of heat Q IW In other words, if it is assumed that a cooling abnormality occurs and the cooling effect of the cooling device 13 on the IPM 11 becomes zero, the heat quantity Q calculated by the above formula (5) CW can be considered to be zero. In other words, the heat quantity Q in the above equation (4) CW If we set it to zero, the estimated condenser temperature T C can be derived.

[0060] As described above, the control device 20 calculates the estimated IPM temperature value T', which is the estimated temperature value of the IPM 11 when it is assumed that the amount of heat transferred from the IPM 11, which is the first object to be monitored, to the cooling path 13a is zero. IPM and the IPM temperature T IPM Based on this, the amount of heat Q transferred from the IPM 11 to the cooling path 13a is IW Then, the control device 20 calculates the amount of heat Q IW and the heat generation amount Q according to the current operating state of the capacitor 12, which is the second monitoring object. C and the estimated capacitor temperature T C is derived.

[0061] That is, since the IPM 11 and the condenser 12 are cooled by the common cooling path 13a, the amount of heat transferred from the IPM 11 to the cooling path 13a is Q IW If this can be understood, the amount of heat Q transferred from the condenser 12 to the cooling path 13a can be calculated. CW Therefore, the amount of heat Q IW and the amount of heat generated by the capacitor 12 according to its current operating state Q C and the estimated capacitor temperature T CBy deriving the above equation, it becomes possible to estimate the temperature of condenser 12 taking into consideration the approximate amount of heat transferred from condenser 12 to cooling path 13a, which may change due to a cooling abnormality, and it becomes possible to accurately estimate the temperature of condenser 12 even if a cooling abnormality occurs.

[0062] More specifically, for example, the control device 20 calculates the amount of heat Q transferred from the IPM 11 to the cooling path 13a. IW and the heat generation amount Q according to the current operating state of the IPM11 I k, which is the ratio of C Based on this, the amount of heat Q transferred from the condenser 12 to the cooling path 13a is CW Then, the control device 20 calculates the amount of heat Q CW and the amount of heat generated by the capacitor 12 according to its current operating state Q C and the estimated capacitor temperature T C As a result, the amount of heat transferred from the condenser 12 to the cooling path 13a, Q CW Therefore, even if a cooling abnormality occurs, the temperature of the condenser 12 can be estimated with high accuracy.

[0063] Furthermore, the control device 20 calculates the condenser temperature estimated value T C This makes it possible to more accurately estimate the temperature of the condenser 12 by taking into consideration the amount of heat transferred from the IPM 11 to the condenser 12 (in the example of this embodiment, the amount of heat transferred from the IPM 11 to the condenser 12 via the first bus bar 19a and the second bus bar 19b). IW By taking this into consideration (see, for example, the above equation (2)), it becomes possible to estimate the temperature of the capacitor 12 with higher accuracy.

[0064] <Example of IPM output control using a control device> Each of the above equations (2) to (4) includes a parameter t that represents a time. Therefore, the control device 20 can estimate the future temperature of the condenser 12 by substituting a value corresponding to a time after the present for t in each of the above equations (2) to (4).

[0065] Therefore, in this embodiment, the control device 20 estimates the future temperature of the capacitor 12, and when it is predicted that the temperature of the capacitor 12 will exceed a predetermined threshold, it reduces the power output from the IPM 11 compared to when the temperature of the capacitor 12 does not exceed the threshold. This makes it possible to suppress a rise in the temperature of the capacitor 12 and to suppress the occurrence of an overshoot (hereinafter simply referred to as "overshoot") in which the temperature of the capacitor 12 exceeds the threshold.

[0066] An example of output control of the IPM 11 based on the results of estimating the future temperature of the capacitor 12 will be described below with reference to Fig. 3. In the upper and lower diagrams in Fig. 3, the vertical axis on the left represents the temperature [°C] of the capacitor 12, the vertical axis on the right represents the output (i.e., power) [W] of the IPM 11, and the horizontal axis represents time.

[0067] As shown in the upper diagram of Fig. 3, at time t1 when the output of the IPM 11 is set to P1 [W], the control device 20 estimates the future temperature of the capacitor 12 if the output of the IPM 11 is maintained at the current P1 [W]. As a result, the estimated temperature of the capacitor 12 is calculated based on the temperature T TH It is assumed that the temperature exceeds T TH is determined by the manufacturer of the temperature estimation system 1 in consideration of the heat resistance performance of the capacitor 12, and is set in the control device 20 in advance.

[0068] In this way, if the current output (P1 [W] in the example described here) is maintained, the temperature of the capacitor 12 will rise to temperature T THIf it is predicted that the output voltage will exceed P1 [W], the control device 20 reduces the output of the IPM 11 to less than P1 [W] from time t1, for example, as shown in the lower diagram of Figure 3. This makes it possible to suppress the temperature rise of the capacitor 12 after time t1, and to suppress the occurrence of overshoot.

[0069] More specifically, for example, the control device 20 reduces the output of the IPM 11 in stages over time, such as P2 [W], P3 [W], and P4 [W] (where P1 [W]>P2 [W]>P3 [W]>P4 [W]). This enables the control device 20 to perform appropriate power saving control, such as finely controlling the output of the IPM 11 based on the accurately estimated future temperature of the capacitor 12 and gradually reducing the output of the IPM 11 so as not to cause overshoot.

[0070] On the other hand, if the control device 20 cannot accurately estimate the temperature of the capacitor 12, it will be forced to limit the output of the IPM 11 with a sufficient safety margin in order to reliably protect the capacitor 12 from overheating. As a result, excessive output limitation tends to be implemented, and the output performance of the IPM 11 may not be effectively exhibited.

[0071] As described above, according to this embodiment, it is possible to provide a temperature estimation system 1 that enables accurate estimation of the temperature of the condenser 12, which is a second object to be monitored that is different from the first object to be monitored, based on the temperature of the IPM 11, which is a first object to be monitored, detected by the temperature sensor 14. This also contributes to improving the energy efficiency of the vehicle.

[0072] Although one embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiment may be combined in any manner without departing from the spirit of the invention.

[0073] For example, in the above-described embodiment, an example was described in which the temperature estimation system 1 was applied to an electric vehicle, but the temperature estimation system 1 is not limited to electric vehicles and can also be applied to various types of equipment equipped with multiple electronic components.

[0074] This specification etc. describes at least the following items. The components etc. that correspond to those in the above-mentioned embodiment are shown in parentheses, but the present invention is not limited to these.

[0075] (1) a first monitored object (IPM 11) and a second monitored object (capacitor 12), each of which is composed of one or more electronic components; a cooling device (cooling device 13) having a cooling path (cooling path 13a) through which a refrigerant for cooling the first monitored object and the second monitored object flows; a temperature sensor (temperature sensor 14) that detects the temperature of the first monitoring object; a control device (control device 20) that estimates the temperature of the second monitored object based on the temperature of the first monitored object detected by the temperature sensor; A temperature estimation system (temperature estimation system 1) comprising: The control device a first temperature estimate (IPM temperature estimate T') that is an estimate of the temperature of the first monitored object when the amount of heat transferred from the first monitored object to the cooling path is assumed to be zero; IPM ) and the temperature of the first monitored object (IPM temperature T IPM ) based on the amount of heat transferred from the first monitored object to the cooling path (amount of heat Q IW ) is derived, The amount of heat transferred from the first monitored object to the cooling path and the amount of heat generated according to the current operating state of the second monitored object (heat generation amount Q C ) and a second temperature estimate (condenser temperature estimate T C ) is estimated, Temperature estimation system.

[0076] According to (1), it is possible to estimate the temperature of the second monitored object by taking into account the approximate amount of heat transferred from the second monitored object to the cooling path, which may change due to a cooling abnormality, and it is possible to accurately estimate the temperature of the second monitored object even if a cooling abnormality occurs.

[0077] (2) The temperature estimation system according to (1), The control device deriving the amount of heat transferred from the second monitored object to the cooling path based on a ratio between the amount of heat transferred from the first monitored object to the amount of heat generated according to the current operating state of the first monitored object and the amount of heat generated according to the current operating state of the second monitored object; estimating the second temperature estimated value based on the amount of heat transferred from the second monitoring object to a cooling path and the amount of heat generated according to a current operating state of the second monitoring object; Temperature estimation system.

[0078] According to (2), it is possible to estimate the temperature of the second monitored object by taking into account the amount of heat transferred from the second monitored object to the cooling path, and it is possible to accurately estimate the temperature of the second monitored object even if a cooling abnormality occurs.

[0079] (3) The temperature estimation system according to (1), The control device further estimates the second temperature estimated value based on the amount of heat transferred from the first monitored object to the second monitored object. Temperature estimation system.

[0080] According to (3), it is possible to estimate the temperature of the second monitored object taking into account the amount of heat transferred from the first monitored object to the second monitored object, thereby making it possible to accurately estimate the temperature of the second monitored object.

[0081] (4) The temperature estimation system according to (2), The control device further estimates the second temperature estimated value based on the amount of heat transferred from the first monitored object to the second monitored object. Temperature estimation system.

[0082] According to (4), it is possible to estimate the temperature of the second monitored object taking into account the amount of heat transferred from the first monitored object to the second monitored object, thereby making it possible to accurately estimate the temperature of the second monitored object.

[0083] (5) A temperature estimation system according to any one of (1) to (4), the first monitoring object is a power conversion device capable of outputting a predetermined power, the second monitored object is connected to the output side of the first monitored object; the control device is further configured to be able to control the power output from the first monitored object, and when the second temperature estimation value exceeds a threshold, the control device reduces the power output from the first monitored object compared to when the second temperature estimation value does not exceed the threshold. Temperature estimation system.

[0084] According to (5), it is possible to prevent the temperature of the second monitored object from overshooting above the threshold.

[0085] (6) The temperature estimation system according to (5), the control device, when the second temperature estimation value exceeds the threshold, gradually reduces the power output from the first monitored object; Temperature estimation system.

[0086] According to (6), it is possible to perform appropriate power saving control (output limitation) such as gradually reducing the output of the first monitored object so as to prevent an overshoot in which the temperature of the second monitored object exceeds the threshold. [Explanation of symbols]

[0087] 1 Temperature Estimation System 1 11 IPM (First Monitoring Object) 12 Capacitor (second monitored object) 13 Cooling device 13a Cooling path 14 Temperature Sensor 20 Control device

Claims

1. a first monitored object and a second monitored object, each of which is configured by one or more electronic components; a cooling device having a cooling path through which a refrigerant flows to cool the first monitored object and the second monitored object; a temperature sensor for detecting a temperature of the first monitoring object; a control device that estimates a temperature of the second monitored object based on the temperature of the first monitored object detected by the temperature sensor; A temperature estimation system comprising: the first monitored object and the second monitored object are thermally connected to each other, The control device deriving the amount of heat transferred from the first monitored object to the cooling path based on a first temperature estimation value, which is a temperature estimation value of the first monitored object when it is assumed that the amount of heat transferred from the first monitored object to the cooling path is zero, and the temperature of the first monitored object; estimating a second temperature estimation value, which is the temperature of the second monitoring object, based on the amount of heat transferred from the first monitoring object to a cooling path and the amount of heat generated according to the current operating state of the second monitoring object; further estimating the second temperature estimated value based on the amount of heat transferred from the first monitored object to the second monitored object; Temperature estimation system.

2. 2. The temperature estimation system according to claim 1, The control device deriving the amount of heat transferred from the second monitored object to the cooling path based on a ratio between the amount of heat transferred from the first monitored object to the amount of heat generated according to the current operating state of the first monitored object and the amount of heat generated according to the current operating state of the second monitored object; estimating the second temperature estimated value based on the amount of heat transferred from the second monitoring object to a cooling path and the amount of heat generated according to a current operating state of the second monitoring object; Temperature estimation system.

3. 3. The temperature estimation system according to claim 1, the first monitoring object is a power conversion device capable of outputting a predetermined power, the second monitored object is connected to the output side of the first monitored object; the control device is further configured to be able to control the power output from the first monitored object, and when the second temperature estimation value exceeds a threshold, the control device reduces the power output from the first monitored object compared to when the second temperature estimation value does not exceed the threshold. Temperature estimation system.

4. 4. The temperature estimation system according to claim 3, the control device, when the second temperature estimation value exceeds the threshold, gradually reduces the power output from the first monitored object; Temperature estimation system.

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