JP2023160416A - temperature estimation system - Google Patents

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

The present invention relates to a temperature estimation system.

In recent years, efforts toward the realization of a low-carbon or decarbonized society have become active as concrete measures against global climate change. As one of these initiatives, in order to reduce CO ₂ emissions and improve energy efficiency in vehicles such as cars, electric vehicles such as electric vehicles or hybrid electric vehicles that use a motor as a drive source are being developed. Research and development is underway.

For systems with multiple electronic components, overheating of electronic components can be suppressed by monitoring the temperature of each electronic component and limiting the output if the temperature of any electronic component exceeds a predetermined temperature. There is something to do.

For example, Patent Document 1 below states that among a plurality of switching elements, the temperature of the element with the minimum "grace temperature", which is obtained by subtracting the current temperature of the element from the output limit temperature set for each element, is set as the "limiting target temperature". A technique is disclosed in which the output limit of the power conversion circuit is started when the limit target temperature reaches the output limit temperature of the element.

Further, in Patent Document 2 below, the capacitor temperature, which is the temperature of the capacitor, is estimated based on the capacitor current, which is the current flowing in the capacitor connected in parallel to the battery, and the temperature of the capacitor is estimated based on the capacitor temperature. A technique has been disclosed that limits the current flowing through an inverter.

JP2017-169260A Japanese Patent Application Publication No. 2018-148695

If a temperature sensor is provided for each object whose temperature is to be monitored, a large number of temperature sensors will 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 conventional technology, there is room for improvement from the viewpoint of accurately estimating the temperature of the second monitored object.

The present invention provides a temperature estimation system that makes it possible to accurately estimate the temperature of a second monitoring target, which is different from the first monitoring target, based on the temperature of the first monitoring target detected by a temperature sensor. provide.

One aspect of the present invention is
a first monitoring object and a second monitoring object, each of which is composed of one or more electronic components;
a cooling device having a cooling path through which a refrigerant for cooling the first monitoring object and the second monitoring object flows;
a temperature sensor that detects the temperature of the first monitoring object;
a control device that estimates the temperature of the second monitoring target based on the temperature of the first monitoring target detected by the temperature sensor;
A temperature estimation system comprising:
The control device includes:
Based on the temperature of the first monitored object and a first temperature estimate that is an estimated temperature of the first monitored object assuming that the amount of heat transmitted from the first monitored object to the cooling path is zero. deriving the amount of heat transmitted from the first monitoring object to the cooling path,
a second temperature estimate, which is the temperature of the second monitoring target, based on the amount of heat transmitted from the first monitoring target to the cooling path and the amount of heat generated according to the current operating state of the second monitoring target; estimate,
It is a temperature estimation system.

According to the present invention, temperature estimation makes it possible to accurately estimate the temperature of a second monitoring target different from the first monitoring target based on the temperature of the first monitoring target detected by a temperature sensor. system can be provided.

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. 1 is a diagram showing an example of an electrical or thermal connection relationship between an IPM 11, a capacitor 12, and a cooling device 13 in the temperature estimation system 1. FIG. FIG. 2 is a diagram showing an example of output control of the IPM 11 based on a result of estimating the temperature of the capacitor 12 by the control device 20 of the temperature estimation system 1. FIG.

Hereinafter, one embodiment of the temperature estimation system of the present invention will be described in detail with reference to the accompanying drawings. In addition, below, the same or similar code|symbol may be attached|subjected to the same or similar element, and the description may be abbreviate|omitted or simplified suitably.

<Temperature estimation system>
The temperature estimation system of this embodiment is a system that makes it possible to estimate the temperature of a second monitoring target different from the first monitoring target, based on the temperature of the first monitoring target detected by a temperature sensor. It is. Thereby, the temperature of the second monitoring object can be obtained without providing a temperature sensor for detecting the temperature of the second monitoring object, and the configuration can be simplified.

Here, the first monitoring object and the second monitoring object are each made up of one or more electronic components, and are objects that can generate heat when operating (in other words, being supplied with electric power). I can do it. Although the articles as the first monitoring object and the second monitoring object are not particularly limited, in this embodiment, an IPM (Intelligent Power Module) is the first monitoring object, and the output side of the IPM, which is the first monitoring object, is An example will be described in which a capacitor connected to the second monitoring target is a capacitor connected to the second monitoring target.

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 that centrally controls the entire temperature estimation system 1. 20. In this embodiment, it is assumed that the temperature estimation system 1 is installed in an electric vehicle (not shown) that includes a motor as a drive source, such as an electric vehicle or a hybrid electric vehicle. Hereinafter, the electric vehicle equipped with the temperature estimation system 1 will also be simply referred to as a "vehicle".

The voltage and current source PS is a voltage and current source configured to be able to output a predetermined amount of power to the power conversion device 10, and is, for example, a battery as a power storage device mounted on a vehicle. More specifically, the voltage and current source PS is configured by connecting a plurality of energy storage cells realized by lithium ion batteries, nickel metal hydride batteries, etc. in series or in series and parallel, and outputs a high voltage of 100 to 200 [V]. A high voltage battery (so-called driving battery) can be used. Further, the voltage and current source PS is not limited to such a high voltage battery, but may be, for example, a low voltage battery (so-called auxiliary battery) capable of outputting a low voltage of about 12 [V], a fuel cell, a generator, etc. It may be.

The load EL is an electric device that operates using electric power supplied from the power conversion device 10, and is, for example, a motor that is a drive source of a vehicle (hereinafter also referred to as a "drive motor"), or electric power supplied to a drive motor. It can be an inverter that performs the conversion. Further, the load EL is not limited to such a drive motor or inverter, but may be, for example, a motor that drives a fan, a pump, or a compressor (for example, a motor of an air conditioner) mounted on a vehicle.

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

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), and the like. The IPM 11 generates predetermined power by switching these plurality of switching elements under the control of the control device 20, and outputs the generated power.

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.

Specifically, as shown in FIG. 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 configured using a copper plate or the like. . The power output from the IPM 11 is smoothed by a capacitor 12 and then supplied to the load EL. Thereby, stable power with small ripple can be supplied to the load EL.

The cooling device 13 is a device that cools the IPM 11 and the condenser 12. Specifically, as shown in FIG. 2, the cooling device 13 has a cooling path 13a through which a refrigerant (for example, cooling water called "LLC") that cools the IPM 11 and the condenser 12 flows; It includes a radiator (not shown) as a heat radiator that radiates heat of the refrigerant to the outside air, and a pump (not shown) that circulates the refrigerant within the cooling device 13. The IPM 11 and the condenser 12 are arranged on the cooling device 13 in a state where they can exchange heat with the refrigerant flowing through the cooling path 13a, and the heat of the IPM 11 and the condenser 12 is transferred to the refrigerant flowing through the cooling path 13a. , the heat is radiated to the outside air by a radiator. Thereby, the IPM 11 and the capacitor 12, which can generate heat, can be cooled by the cooling device 13, and a rise in their temperatures can be suppressed.

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

The control device 20 is a computer that centrally controls the entire temperature estimation system 1, and includes, for example, a processor (for example, a so-called CPU) that performs various calculations, and a non-transitory storage medium (for example, a so-called CPU) that stores various information (for example, data and programs). For example, it is realized by an ECU (Electronic Control Unit) that includes a storage device having a flash memory (for example, a flash memory), an input/output device that controls input/output of data between the inside and outside of the control device 20, and the like. Note that the control device 20 may be realized by one ECU, or may be realized by a plurality of ECUs working together.

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 appropriately outputting a predetermined control signal to the power conversion device 10, for example.

Although details will be described later, in this embodiment, the control device 20 estimates the temperature of the capacitor 12 based on the temperature of the IPM 11 detected by the temperature sensor 14, and if the temperature of the capacitor 12 exceeds a predetermined threshold, , the power output from the IPM 11 is made smaller than when the temperature of the capacitor 12 does not exceed the threshold. As a result, when the temperature of the capacitor 12 is estimated to exceed a predetermined threshold (in other words, the capacitor 12 is in a high temperature state), the power output from the IPM 11 (in other words, the power supplied to the capacitor 12) is By making it small, the temperature rise of the capacitor 12 can be suppressed. Therefore, overheating of the capacitor 12 can be suppressed, and deterioration and damage of the capacitor 12 due to overheating can be suppressed.

By the way, during operation of the temperature estimation system 1, a "cooling abnormality" may occur in which the cooling performance of the cooling device 13 is lower than normal due to some factor such as refrigerant leakage from the cooling device 13 or clogging of the cooling path 13a. There is. When such a cooling abnormality occurs, the amount of heat transmitted from the IPM 11 and the condenser 12 to the cooling path 13a (that is, the refrigerant of the cooling device 13) may change from normal. Therefore, if the control device 20 estimates the temperature of the capacitor 12 by keeping the amount of heat transmitted from the IPM 11 and the capacitor 12 to the cooling path 13a constant at all times, the temperature of the capacitor 12 will be accurately estimated when a cooling abnormality occurs. It becomes difficult to estimate well.

Therefore, in this embodiment, the temperature of the capacitor 12 is estimated by estimating the temperature of the capacitor 12 using the estimation method described below, taking into account the amount of heat transmitted from the IPM 11 and the capacitor 12 to the cooling path 13a, which may change due to cooling abnormality. Allows you to estimate. This makes it possible to accurately estimate the temperature of the capacitor 12 even if a cooling abnormality occurs.

<How to estimate capacitor temperature>
For example, when the temperature estimation system 1 is started by turning on the ignition power source or the accessory power source of the vehicle, the control device 20 performs the following operation at a predetermined timing (for example, at a predetermined cycle) during the startup. The temperature of the capacitor 12 is estimated using the following estimation method.

First, the control device 20 derives the amount of heat Q _IW transmitted from the IPM 11 to the cooling path 13a, which may change due to a cooling abnormality. The amount of heat Q _IW can be derived, for example, by the following equation (1).

In the above equation (1), T' _IPM is the temperature estimation of the IPM 11 when the amount of heat transmitted from the IPM 11 to the cooling path 13a is assumed to be zero (in other words, when the cooling effect on the IPM 11 by the cooling device 13 is assumed to be zero). This is an example of the first temperature estimate. Hereinafter, the estimated temperature value of the IPM 11 is also referred to as the "estimated IPM temperature value", and the estimated value of the IPM temperature when the amount of heat transmitted from the IPM 11 to the cooling path 13a is assumed to be zero is also referred to as the "estimated IPM temperature value T' _IPM ". .

In this embodiment, it is assumed that an IPM temperature estimation map for deriving the IPM temperature estimation value T' _IPM is stored in advance in the control device 20. This IPM temperature estimation map is a map (information) that defines the IPM temperature estimation value T' _IPM for each output voltage value and output current value that the IPM 11 can take. 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 IPM temperature estimation map, and determines the current output voltage value and output of the IPM 11. An estimated IPM temperature value T' _IPM corresponding to the current value is derived. As T' _IPM in the above equation (1), the IPM temperature estimated value T' _IPM corresponding to the current output of the IPM 11 derived in this way is used.

In the above equation (1), T _IPM is the actual value of the temperature of the IPM 11 detected by the temperature sensor 14. Hereinafter, the actual value of the temperature of the IPM 11 detected by the temperature sensor 14 will also be referred to as "IPM temperature _TIPM ."

In the above equation (1), R _w is the thermal resistance from the IPM 11 to the cooling path 13a. As the thermal resistance _Rw , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20.

In a normal state when no cooling abnormality occurs, the IPM temperature T _IPM is smaller than the estimated IPM temperature T' _IPM , so the amount of heat Q _IW derived from the above equation (1) becomes larger than zero. On the other hand, when a cooling abnormality occurs, the IPM temperature T _IPM approaches the estimated IPM temperature value T' _IPM . Therefore, the amount of heat Q _IW derived from the above equation (1) becomes smaller than in normal times, and may become approximately zero, for example.

Next, the control device 20 determines whether _the capacitor ₁₂ Estimate the temperature of

In the example of 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 transmitted from the IPM 11 to the capacitor 12 via the first bus bar 19a and the second bus bar 19b.

Therefore, the control device 20 derives the temperature of the first bus bar 19a (hereinafter also referred to as "first bus bar temperature T _Bus1 ") based on the IPM temperature T _IPM , and derives the temperature of the second bus bar 19 b based on the first bus bar temperature T _Bus1 . (hereinafter also referred to as "second bus bar temperature T _Bus2 "), and the temperature of the capacitor 12 is estimated based on the second bus bar temperature T _Bus2 . Thereby, the temperature of the capacitor 12 can be estimated taking into consideration the amount of heat transmitted from the IPM 11 to the capacitor 12 via the first bus bar 19a and the second bus bar 19b, and it becomes possible to estimate the temperature of the capacitor 12 with high accuracy.

To explain specifically, the first bus bar temperature T _Bus1 can be derived by, for example, the following equation (2).

In the above equation (2), T _IPM is the same as the IPM temperature T _IPM in the above equation (1). T' _Bus1 can be, for example, the first bus bar temperature T _Bus1 derived most recently (that is, the previous time). R _th1 is the thermal resistance from the IPM 11 to the first bus bar 19a. As the thermal resistance R _th1 , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20.

In the above equation (2), Q _I is the amount of heat generated by the IPM 11 according to the current output of the IPM 11 (in other words, the current operating state of the IPM 11). The calorific value Q _I can be derived, for example, based on the IPM temperature T _IPM and the heat capacity C _IPM of the IPM 11. In this case, as the heat capacity C _IPM , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20.

Further, for example, a map that defines the amount of heat generated by the IPM 11 for each output voltage value and output current value that the IPM 11 can take is stored in advance in the control device 20, and the control device 20 uses this map and the voltage sensor 15 to detect The amount of heat generated Q _I corresponding to the current output voltage value and output current value of the IPM 11 may be derived by referring to the output voltage value detected by the current sensor 16 and the output current value detected by the current sensor 16.

In the above equation (2), Q _IW is the amount of heat Q _IW derived from the above equation (1). Note that, as described above, during normal conditions when no cooling abnormality occurs, the amount of heat Q _IW is greater than zero. On the other hand, when a cooling abnormality occurs, the amount of heat Q _IW becomes smaller than when it is normal, and may become approximately zero, for example.

In the above equation (2), C _Bus1 is the heat capacity of the first bus bar 19a. As the heat capacity C _Bus1 , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20.

In the above equation (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 activated. As an example, the current first bus bar temperature T _Bus1 can be derived by inserting a value corresponding to the elapsed time from when the temperature estimation system 1 was most recently activated to the present time into t in the above equation (2). Further, as another example, the future first bus bar temperature T _Bus1 can be derived by inserting a value corresponding to a period after the present time into t in the above equation (2).

The second bus bar temperature T _Bus2 can be derived, for example, by the following equation (3).

In the above equation (3), T _Bus1 is the first bus bar temperature T _Bus1 derived from the above equation (2). T' _Bus2 can be, for example, the second bus bar temperature T _Bus2 derived most recently (that is, the previous time). R _th2 is the thermal resistance from the first bus bar 19a to the second bus bar 19b. As the thermal resistance R _th2 , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20. C _Bus2 is the heat capacity of the second bus bar 19b. As the heat capacity C _Bus2 , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20. t is the same as t in the above equation (2).

The capacitor temperature estimated value _TC , which is the estimated value of the temperature of the capacitor 12, is an example of the second temperature estimated value, and can be derived, for example, by the following equation (4).

In the above equation (4), T _Bus2 is the second bus bar temperature T _Bus2 derived from the above equation (3). T' _C can be, for example, the most recently (ie, previous) derived capacitor temperature estimate T _C. R _th3 is the thermal resistance from the second bus bar 19b to the capacitor 12. As the thermal resistance R _th3 , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20.

In the above equation (4), _QC is the amount of heat generated by the capacitor 12 according to the current operating state of the capacitor 12 (that is, the power currently supplied to the capacitor 12; in other words, the current output of the IPM 11).

In this embodiment, it is assumed that a capacitor heat generation map for deriving the heat generation amount _QC is stored in advance in the control device 20. This capacitor heat generation amount map is a map that defines the heat generation amount of the capacitor 12 for each output voltage value and output current value that the IPM 11 can take. 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 map, and determines the current output voltage value and output value of the IPM 11. The amount of heat generated by the capacitor 12 corresponding to the current value is derived as the amount of heat generated _QC . The calorific value Q _C derived in this way is used as Q _C in the above equation (4).

In the above equation (4), C _C is the heat capacity of the capacitor 12. As the heat capacity _C , for example, a predetermined value determined through experiments or the like is stored in advance in the control device 20. t is the same as t in the above equation (2), etc.

In the above equation (4), Q _CW is the amount of heat transmitted from the condenser 12 to the cooling path 13a, which can change due to a cooling abnormality. The amount of heat Q _CW can be derived based on the ratio of the amount of heat Q _IW transmitted from the IPM 11 to the cooling path 13 a and the amount of heat generated Q _I of the IPM 11 and the amount of heat generated Q _C of the capacitor 12 . More specifically, if the ratio between the amount of heat Q _IW and the amount of heat generated Q _I is k (that is, k = amount of heat Q _IW / amount of heat generated Q _I ), then the amount of heat Q _CW transmitted from the capacitor 12 to the cooling path 13a is, for example, It can be derived by the following equation (5).

Note that, as described above, when a cooling abnormality occurs, the amount of heat Q _IW can be approximately zero, and therefore k can also be approximately zero. 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 amount of heat Q _CW derived from the above equation (5) can be regarded as zero. That is, by setting the amount of heat Q _CW in the above equation (4) to zero, it is possible to derive the estimated capacitor temperature value T _C when it is assumed that a cooling abnormality has occurred and the cooling effect of the cooling device 13 on the IPM 11 has become zero.

As explained above, the control device 20 calculates the IPM temperature estimate T' _IPM , which is the temperature estimate of the IPM 11 assuming that the amount of heat transmitted from the IPM 11, which is the first monitoring object, to the cooling path 13a is zero; Based on the IPM temperature T _IPM , which is the actual measured value of the temperature of the IPM 11 detected by the temperature sensor 14, the amount of heat Q _IW transmitted from the IPM 11 to the cooling path 13a is derived. Then, the control device 20 determines the capacitor temperature, which is the estimated value of the temperature of the capacitor 12, based on this heat amount _QIW and the heat value _QC corresponding to the current operating state of the capacitor 12, which is the second monitoring target. Derive the estimated value _TC .

That is, since the IPM 11 and the condenser 12 are cooled by the common cooling path 13a, if the amount of heat Q IW transferred from the IPM _{11 to the cooling path 13a can be determined, the amount of heat Q CW transferred} from the condenser 12 to the cooling path 13a can also be roughly determined. Therefore, by deriving the estimated capacitor temperature T C based on the amount of heat Q _IW and the amount of heat generated Q _C according to the current operating state of the capacitor 12, the estimated temperature value T _C of the capacitor can be calculated based on the amount of heat Q IW and the amount of heat generated Q C according to the current operating state of the capacitor 12. It becomes possible to estimate the temperature of the capacitor 12 by taking into consideration the approximate amount of heat transmitted to the capacitor 12, and even if a cooling abnormality occurs, it becomes possible to estimate the temperature of the capacitor 12 with high accuracy.

More specifically, for example, the control device 20 calculates k, which is the ratio of the amount of heat _QIW transferred from the IPM 11 to the cooling path 13a, and the amount of heat generated _QI according to the current operating state of the IPM 11, and the current amount of the capacitor 12. The amount of heat Q _CW transmitted from the capacitor 12 to the cooling path 13a is derived based on the amount of heat generated Q _C according to the operating state. Then, the control device 20 derives the estimated capacitor temperature value T _C based on this amount of heat Q _CW and the amount of heat generated Q _C according to the current operating state of the capacitor 12 . This makes it possible to estimate the temperature of the capacitor 12 by taking into account the amount of heat Q _CW transferred from the capacitor 12 to the cooling path 13a, and even if a cooling abnormality occurs, it is possible to estimate the temperature of the capacitor 12 with high accuracy. Become.

Further, the control device 20 can further derive the estimated capacitor temperature value T _C based on the amount of heat transmitted from the IPM 11 to the capacitor 12 . As a result, the temperature of the capacitor 12 can be estimated more accurately by taking into account the amount of heat transferred from the IPM 11 to the capacitor 12 (in the example of this embodiment, 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). It becomes possible to do so. By setting the amount of heat transferred from the IPM 11 to the capacitor 12 in consideration of the amount of heat _QIW transferred from the IPM 11 to the cooling path 13a (see, for example, equation (2) above), the temperature of the capacitor 12 can be estimated with higher accuracy. It becomes possible.

<Example of IPM output control by control device>
Each of the above equations (2) to (4) includes t as a parameter representing time. Therefore, the control device 20 can estimate the future temperature of the capacitor 12 by inserting a value corresponding to a time after the present time into t in each of the above equations (2) to (4). .

Therefore, in the present embodiment, the control device 20 estimates the future temperature of the capacitor 12, and if the temperature of the capacitor 12 is predicted to exceed a predetermined threshold, if the temperature of the capacitor 12 does not exceed the threshold, The power output from the IPM 11 is made smaller than that of the IPM 11. Thereby, it is possible to suppress the temperature rise of the capacitor 12, and it is possible to suppress the occurrence of an overshoot (hereinafter also simply referred to as "overshoot") in which the temperature of the capacitor 12 exceeds a threshold value.

Hereinafter, an example of output control of the IPM 11 based on the estimation result of the future temperature of the capacitor 12 will be described with reference to FIG. In the upper and lower diagrams in FIG. 3, the left vertical axis represents the temperature [°C] of the capacitor 12, the right vertical axis represents the output (i.e. power) [W] of the IPM 11, and the horizontal axis represents the time. shall be expressed.

As shown in the upper diagram of FIG. 3, the control device 20 determines the future value of the capacitor 12 when the output of the IPM 11 is maintained at the current P1 [W] at a time t1 when the output of the IPM 11 is set to P1 [W]. Estimate temperature. Assume that as a result, the estimated temperature of the capacitor 12 exceeds a predetermined threshold temperature _TTH , as shown in the upper diagram of FIG. Note that the temperature _TTH is determined by the manufacturer of the temperature estimation system 1, etc., taking into consideration the heat resistance performance of the capacitor 12, etc., and is set in the control device 20 in advance.

In this way, if it is predicted that the temperature of the capacitor 12 will exceed the temperature _TTH in the future if the current output (P1 [W] in the example described here) is maintained, then For example, the control device 20 makes the output of the IPM 11 smaller than P1 [W] from time t1. Thereby, it is possible to suppress the temperature rise of the capacitor 12 after time t1, and it is possible to suppress the occurrence of overshoot.

More specifically, for example, the control device 20 changes the output of the IPM 11 to P2[W], P3[W], P4[W] (where P1[W]>P2[W]>P3 [W]>P4[W]). As a result, the control device 20 finely controls the output of the IPM 11 based on the accurately estimated future temperature of the capacitor 12, and gradually reduces the output of the IPM 11 to prevent overshoot from occurring. This makes it possible to perform power-saving control.

On the other hand, if the control device 20 is unable to accurately estimate the temperature of the capacitor 12, the output of the IPM 11 should be limited by taking into account a generous safety margin in order to reliably protect the capacitor 12 from overheating. I have no choice but to do it. As a result, excessive output restrictions tend to be implemented, and the output performance of the IPM 11 may not be effectively demonstrated.

As explained above, according to the present embodiment, based on the temperature of the IPM 11, which is the first monitored object, detected by the temperature sensor 14, the second monitored object is different from the first monitored object. It is possible to provide a temperature estimation system 1 that makes it possible to accurately estimate the temperature of the capacitor 12. This also contributes to improving the energy efficiency of the vehicle.

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 this embodiment. It is clear that those skilled in the art can come up with various changes or modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood. Further, each component in the embodiments described above may be arbitrarily combined without departing from the spirit of the invention.

For example, in the embodiment described above, an example was explained in which the temperature estimation system 1 is applied to an electric vehicle, but the temperature estimation system 1 is not limited to electric vehicles, but can also be applied to various devices including multiple electronic components. It is.

This specification etc. describes at least the following matters. Corresponding components in the above-described embodiment are shown in parentheses, but the present invention is not limited thereto.

(1) A first monitoring object (IPM 11) and a second monitoring 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 monitoring object and the second monitoring 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 monitoring object based on the temperature of the first monitoring object detected by the temperature sensor;
A temperature estimation system (temperature estimation system 1) comprising:
The control device includes:
a first temperature estimate (IPM temperature estimate T' _IPM ) which is an estimated temperature value of the first monitored object when the amount of heat transmitted from the first monitored object to the cooling path is assumed to be zero; Deriving the amount of heat (amount of heat Q _IW ) transmitted from the first monitoring object to the cooling path based on the temperature of the first monitoring object (IPM temperature T _IPM ),
The temperature of the second monitored object is determined based on the amount of heat transmitted from the first monitored object to the cooling path and the amount of heat generated (heat amount Q _C ) according to the current operating state of the second monitored object. estimating a certain second temperature estimate (capacitor temperature estimate T _C );
Temperature estimation system.

According to (1), it is possible to estimate the temperature of the second monitoring object by taking into account the approximate amount of heat transferred from the second monitoring object to the cooling path, which can change due to a cooling abnormality, and it is possible to estimate the temperature of the second monitoring object when a cooling abnormality occurs. Even in this case, it is possible to estimate the temperature of the second monitored object with high accuracy.

(2) The temperature estimation system according to (1),
The control device includes:
a ratio between the amount of heat transferred from the first monitoring object to the cooling path and the amount of heat generated according to the current operating state of the first monitoring object; and the amount of heat generated depending on the current operating state of the second monitoring object. Deriving the amount of heat transmitted from the second monitoring object to the cooling path based on
estimating the second temperature estimate based on the amount of heat transmitted from the second monitoring object to the cooling path and the amount of heat depending on the current operating state of the second monitoring object;
Temperature estimation system.

According to (2), it is possible to estimate the temperature of the second monitored object by considering the amount of heat transferred from the second monitored object to the cooling path, and even if a cooling abnormality occurs, the temperature of the second monitored object can be estimated. It becomes possible to estimate the temperature with high accuracy.

(3) The temperature estimation system according to (1),
The control device further estimates the second temperature estimate based on the amount of heat transferred from the first monitoring object to the second monitoring object.
Temperature estimation system.

According to (3), it is possible to estimate the temperature of the second monitored object by taking into account the amount of heat transferred from the first monitored object to the second monitored object, and the temperature of the second monitored object can be estimated with high accuracy. It becomes possible to estimate.

(4) The temperature estimation system according to (2),
The control device further estimates the second temperature estimate based on the amount of heat transferred from the first monitoring object to the second monitoring object.
Temperature estimation system.

According to (4), it is possible to estimate the temperature of the second monitored object by also taking into account the amount of heat transferred from the first monitored object to the second monitored object, and the temperature of the second monitored object can be estimated with high accuracy. It becomes possible to estimate.

(5) The temperature estimation system according to any one of (1) to (4),
The first monitoring target is a power conversion device capable of outputting a predetermined power,
The second monitoring target is connected to the output side of the first monitoring target,
The control device is further configured to be able to control power output from the first monitored object, and when the second temperature estimate exceeds the threshold, the second temperature estimate does not exceed the threshold. reducing the power output from the first monitored object compared to the case where
Temperature estimation system.

According to (5), it is possible to suppress the occurrence of an overshoot in which the temperature of the second monitoring object exceeds the threshold value.

(6) The temperature estimation system according to (5),
The control device step-by-step reduces the power output from the first monitoring object when the second temperature estimate exceeds the threshold.
Temperature estimation system.

According to (6), appropriate power save control (output limitation) is carried out to gradually reduce the output of the first monitored object so that the temperature of the second monitored object does not overshoot beyond the threshold. It becomes possible to do so.

1 Temperature estimation system 1
11 IPM (first monitoring object)
12 Capacitor (second monitoring object)
13 Cooling device 13a Cooling path 14 Temperature sensor 20 Control device

Claims (6)

a first monitoring object and a second monitoring object, each of which is composed of one or more electronic components;
a cooling device having a cooling path through which a refrigerant for cooling the first monitoring object and the second monitoring object flows;
a temperature sensor that detects the temperature of the first monitoring object;
a control device that estimates the temperature of the second monitoring target based on the temperature of the first monitoring target detected by the temperature sensor;
A temperature estimation system comprising:
The control device includes:
Based on a first temperature estimate, which is an estimated temperature of the first monitoring object, assuming that the amount of heat transmitted from the first monitoring object to the cooling path is zero, and the temperature of the first monitoring object. deriving the amount of heat transmitted from the first monitoring object to the cooling path,
a second temperature estimate, which is the temperature of the second monitored object, based on the amount of heat transmitted 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; estimate,
Temperature estimation system. The temperature estimation system according to claim 1,
The control device includes:
a ratio between the amount of heat transferred from the first monitoring object to the cooling path and the amount of heat generated according to the current operating state of the first monitoring object; and the amount of heat generated depending on the current operating state of the second monitoring object. Deriving the amount of heat transmitted from the second monitoring object to the cooling path based on
estimating the second temperature estimate based on the amount of heat transmitted from the second monitoring object to the cooling path and the amount of heat depending on the current operating state of the second monitoring object;
Temperature estimation system. The temperature estimation system according to claim 1,
The control device further estimates the second temperature estimate based on the amount of heat transferred from the first monitoring object to the second monitoring object.
Temperature estimation system. The temperature estimation system according to claim 2,
The control device further estimates the second temperature estimate based on the amount of heat transferred from the first monitoring object to the second monitoring object.
Temperature estimation system. The temperature estimation system according to any one of claims 1 to 4,
The first monitoring target is a power conversion device capable of outputting a predetermined power,
The second monitoring target is connected to the output side of the first monitoring target,
The control device is further configured to be able to control power output from the first monitored object, and when the second temperature estimate exceeds the threshold, the second temperature estimate does not exceed the threshold. reducing the power output from the first monitored object compared to the case where
Temperature estimation system. The temperature estimation system according to claim 5,
The control device step-by-step reduces the power output from the first monitoring object when the second temperature estimate exceeds the threshold.
Temperature estimation system.

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