Protection control device and current control method using same

Abstract

The present invention relates to a protection control device which protects a high-power component, electrically connected to a battery, from overtemperature. The protection control device comprises: a reference temperature acquisition unit which acquires, as a reference temperature, a temperature measured on a first component to which the heat generated in the high-power component by a current flowing through the high-power component is transferred; a first temperature estimation unit which estimates, as a component-to-be-protected temperature, the temperature of the high-power component; and a current control unit which controls, on the basis of the estimated component-to-be-protected temperature, the current that flows through the high-power component. In addition, the first temperature estimation unit estimates, according to a first temperature estimation function, the component-to-be-protected temperature on the basis of the cumulative value of a temporal temperature change amount of the difference between a heat generation amount of the high-power component calculated on the basis of the current and a heat radiation amount of the high-power component calculated on the basis of the reference temperature.

Description

Protection and control device and current control method using the same

[0001] The present invention relates to a protection control device and a current control method using the same, and more particularly to a protection control device that protects high-voltage components electrically connected to a battery mounted on a vehicle from overheating, and a current control method using the same.

[0002] Vehicles such as electric vehicles (EVs) and hybrid vehicles (HVs) are equipped with large-capacity, high-output batteries. Electricity output from the battery is supplied to a drive motor via several high-voltage components, such as switches, relays, and fuses. In such vehicles, depending on the driving conditions, a large current (over 1000 A) may flow through the high-voltage components, which may burn or melt due to Joule heat.

[0003] The following Patent Document 1 discloses a technology for calculating the actual heat generation amount (temperature change amount) over time from the difference between the heat generation amount due to the current supplied to the motor and the heat dissipation amount, and controlling the motor output so that the motor current value converges to a target current value corresponding to the estimated motor temperature indicated by the cumulative value of the accumulated heat generation amount.

[0004] Japanese Patent Application Laid-Open No. 2007-253735

[0005] The technology disclosed in Patent Document 1 calculates the heat dissipation amount used to calculate the temperature change amount based on the difference between the current estimated motor temperature and the ambient temperature (environmental temperature), so it is not possible to accurately estimate the motor temperature. In other words, the technology disclosed in Patent Document 1 does not take into account the amount of heat dissipation that occurs when heat accumulated in the motor is transferred to other surrounding components (high-voltage components), so the accuracy of temperature estimation is insufficient.

[0006] Furthermore, when protecting high-voltage components arranged around the battery from overheating, it has been difficult to measure the temperature of the high-voltage components using a sensor due to structural problems, etc. On the other hand, although the temperature of the battery is generally measured, even if an attempt is made to estimate the temperature of the high-voltage components using the measured battery temperature, the large difference between the heat capacity of the high-voltage components and that of the battery makes it impossible to accurately estimate the temperature of the high-voltage components.

[0007] Therefore, an object of the present invention is to provide a protection control device and a current control method using the same that can more accurately estimate the temperature of components that should be protected from overheating (hereinafter referred to as "protected components").

[0008] The present invention, which aims to solve the above problems, comprises the following invention-specifying matters and technical features.

[0009] According to one aspect, the present invention provides a protection and control device for protecting a high-voltage component electrically connected to a battery from overtemperature. The protection and control device includes a reference temperature acquisition unit that acquires, as a reference temperature, a temperature measured for a first component to which heat generated in the high-voltage component due to a current flowing through the high-voltage component is transferred. A first temperature estimation unit that estimates the temperature of the high-voltage component as a protected-component temperature. The first temperature estimation unit estimates the protected-component temperature based on a cumulative value of a time-dependent temperature change in the difference between the heat generation amount of the high-voltage component calculated based on the current and the heat dissipation amount of the high-voltage component calculated based on the reference temperature, in accordance with a first temperature estimation function.

[0010] Another aspect of the present invention is a current control method for a protection control device that controls a current flowing through a high-voltage component due to charging and discharging of a battery. The current control method includes acquiring a temperature measured for the battery as a reference temperature, estimating the temperature of the high-voltage component as a protected-component temperature, and controlling the current flowing through the high-voltage component based on the estimated protected-component temperature. Estimating the temperature of the high-voltage component as the protected-component temperature includes estimating the protected-component temperature based on a cumulative value of a time-dependent temperature change of a difference between a heat generation amount of the high-voltage component calculated based on the current and a heat dissipation amount of the high-voltage component calculated based on the reference temperature, in accordance with a first temperature estimation function.

[0011] In this specification, the term "means" does not simply mean physical means, but also includes cases where the functions of the means are realized by software. Furthermore, the functions of one means may be realized by two or more physical means, or the functions of two or more means may be realized by one physical means. Furthermore, the term "system" refers to a logical collection of multiple devices (or functional modules that realize specific functions), regardless of whether each device or functional module is contained within a single housing.

[0012] According to the present invention, the temperature of the protected component can be estimated more accurately, and the current output to the motor can be controlled in accordance with the estimated temperature. Therefore, the current output to the motor is appropriately controlled in accordance with the temperature of the protected component, thereby maintaining good driving performance of the vehicle.

[0013] Other technical features, objects, and operational effects or advantages of the present invention will become apparent from the following embodiments described with reference to the accompanying drawings. The effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be present.

[0014] FIG. 1 is a diagram schematically illustrating an example of a vehicle power system to which a protection control device according to an embodiment of the present invention is applied. FIG. 2 is a diagram illustrating an example of a functional model of a protection control device according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a mapping table in a protection control device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a functional model of a protection control device according to an embodiment of the present invention. FIG. 5 is a graph showing an example of the time progression of the temperature of a protected component due to use of an on-board battery. FIG. 6 is a diagram illustrating an example of a functional model of a protection control device according to an embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a functional model of a protection control device according to an embodiment of the present invention. FIG. 8 is a diagram illustrating an example of a functional model of a protection control device according to an embodiment of the present invention.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are merely examples, and are not intended to exclude various modifications or applications of techniques not explicitly described below. The present invention can be implemented in various modifications (e.g., by combining the various embodiments) without departing from the spirit of the present invention. Furthermore, in the following description of the drawings, identical or similar parts are denoted by identical or similar reference numerals. The drawings are schematic and do not necessarily correspond to actual dimensions, ratios, etc. Parts in the drawings may have different dimensional relationships or ratios.

[0016] <First embodiment> This embodiment is characterized by calculating the heat generation amount of a high-voltage component to be protected from overheating based on the current flowing through the component, calculating the heat dissipation amount of the high-voltage component based on the measured battery temperature, calculating a cumulative value by accumulating the temperature change over time of the difference between the calculated heat generation amount and the heat dissipation amount, and estimating the temperature of the high-voltage component (temperature of the protected component) based on the calculated cumulative value.

[0017] 1 is a diagram schematically illustrating an example of a vehicle power system to which a protection control device according to an embodiment of the present invention is applied. As shown in the diagram, the vehicle power system 1 includes, for example, a motor 10 for driving wheels (not shown), an inverter circuit 20 for controlling the drive of the motor 10, a battery pack 30, and a protection control device 40. Because the motor 10, the inverter circuit 20, and the battery pack 30 are known, they will be described below only insofar as they are relevant to the technology according to the present disclosure.

[0018] The battery pack 30 includes, for example, a battery 32 consisting of a group of battery cells, several high-voltage components 34, and the like. The battery pack 30 may also include a battery management system (BMS). The battery management system BMS measures the temperature of the battery 32 using a temperature sensor S and outputs the measured temperature (battery temperature T_BAT). The battery 32 is electrically connected to the inverter circuit 20 via several high-voltage components 34 and supplies the power required to drive the motor 10. The motor 10 includes a motor 10F for front-wheel drive and a motor 10R for rear-wheel drive. In this example, a switch 341, a relay 342, and a fuse 343 are illustrated as the high-voltage components 34.

[0019] The switch 341 is typically a maintenance switch for disconnecting the battery 32 from the wiring system during maintenance. The switch 341 is an example of a high-voltage component 34 electrically connected to the battery 32 via an intervening component 344 made of a conductive material called a bus bar. When the vehicle repeatedly accelerates and decelerates at full speed, a large current flows from the battery 32 to the switch 341, and the switch 341 may burn or melt due to the resulting Joule heat. Therefore, in the present disclosure, the switch 341 is a component (protected component) for protection from overtemperature, and is the subject of temperature estimation. Furthermore, the estimated temperature of the switch 341 is calculated based on the protected component temperature T ＴＧＴ It is sometimes referred to as.

[0020] The protection and control device 40 estimates the temperature of the switch 341 and controls the upper limit of the current flowing through the inverter circuit 20 according to the estimated temperature. This suppresses excessive current flowing through the switch 341 and prevents the switch 341 from burning or melting.

[0021] As described in other embodiments, the battery pack 30 may include a temperature sensor S that measures the temperature of one of the high-voltage components 34, for example, the relay 342.

[0022] 2 is a diagram showing an example of a functional model of a protection and control device according to an embodiment of the present invention. As shown in the figure, the protection and control device 40 includes, for example, a reference temperature acquisition unit 410, a protected component temperature estimation unit 420, and a current limiting unit 430.

[0023] The reference temperature acquisition unit 410 acquires the temperature of the switch 341 (protected component temperature T ＴＧＴ In this embodiment, the reference temperature is the battery temperature T ＢＡＴ That is, the reference temperature acquisition unit 410 acquires the temperature of the battery 32 (battery temperature T ＢＡＴ ) is obtained from the battery management system BMS.

[0024] The protected component temperature estimation unit 420 calculates the temperature change amount ΔT / Δt of the switch 341 over time in accordance with a predetermined temperature estimation function, and estimates the current temperature of the switch 341 (i.e., the protected component temperature T ＴＧＴ = T + ΔT ＴＧＴ The protected component temperature estimation unit 420 estimates the estimated protected component temperature T ＴＧＴ is stored in a register (not shown) and output to the current limiting unit 430. ＴＧＴ The next temperature T ＴＧＴ In the present disclosure, the protected component temperature estimator 420 corresponds to a first temperature estimator.

[0025] Generally, the following equation is known as a temperature estimation function for estimating the temperature T of an object that is heated by a flowing current. ...Equation (1) where r is thermal resistance [Ω], I is current [A], C ｐ is the heat capacity [J / K], A is the surface area [m ２ ], and h is the thermal conductivity [W / (m ２ *K)]. T is the current temperature, T ∞ is the current temperature of the heat sink (heat transfer destination; e.g., the ambient environment).

[0026] In the above formula (1), the left side represents the temperature change of the object over time. The first term on the right side is a heat generation term proportional to the square of the current I, and the second term is called the heat dissipation term. From this formula, the temperature T of the object can be calculated as the cumulative value of the temperature change over time.

[0027] In this embodiment, the temperature estimation function of the protected component temperature estimation unit 420 is defined as follows: ...Equation (2) where r is the thermal resistance [Ω] of the switch 341, I is the current [A] flowing through the switch 341, and C ｐ is the heat capacity of the switch 341 [J / K], A is the surface area of ​​the switch 341 [m ２ ], and h is the thermal conductivity of the switch 341 [W / (m ２ *K)]. Also, T ＴＧＴ is the current temperature of the switch 341, T ＢＡＴ is the battery temperature, a is the heat generation coefficient, and b is the heat dissipation coefficient.

[0028] That is, in this embodiment, it is assumed that the battery 32 is the destination (heat dissipation destination) of the heat from the switch 341, and therefore the temperature of the heat dissipation destination in the heat dissipation term of the temperature estimation function shown in equation (2) is the battery temperature T ＢＡＴ Therefore, the temperature of the switch 341 can be estimated more accurately than in the conventional temperature estimation method that uses the ambient temperature as the reference temperature. Furthermore, the heat generation coefficient a and / or the heat dissipation coefficient b can be dynamically adjusted, for example, according to the value of the current current flowing through the switch 341. For example, the protection and control device 40 includes a coefficient adjustment unit (not shown), which adjusts the value of the heat generation coefficient a to be larger when a large current value (for example, 1000 A or more) is detected. Alternatively, the heat generation coefficient a and / or the heat dissipation coefficient b can be adjusted, for example, according to the accumulated value of the temperature change amount ΔT / Δt, the battery temperature T ＢＡＴ , and / or may be dynamically adjusted in response to the environmental temperature measured by an environmental sensor (not shown), thereby enabling more accurate temperature estimation for the high-voltage component 34 (switch 341) and protecting the switch 341 from overheating without excessively limiting the output current.

[0029] The current limiting unit 430 is configured to limit the temperature T ＴＧＴ The current limiting unit 430 determines the upper limit of the output current depending on, for example, the temperature T ＴＧＴ The current limiting unit 430 includes a mapping table 431 that receives the temperature T of the switch 341 as input and outputs an upper limit value of the output current. In the present disclosure, the mapping table 431 includes a Pout mapping table 431a for determining an upper limit value of the output current flowing from the battery 32 to the inverter circuit 20 in the normal running mode, and a Pin mapping table 431b for determining an upper limit value of the output current flowing from the charger to the battery 32 in the charging mode. For example, FIG. 3 shows an example of a mapping table held by the current limiting unit 430. Specifically, FIG. 3A shows an example of the Pout mapping table 431a, and FIG. 3B shows an example of the Pin mapping table 431b. The current limiting unit 430 switches the mapping table 431 depending on whether the mode is the normal running mode or the charging mode. In the normal running mode, the current limiting unit 430 notifies the inverter circuit 20 of an upper limit value of the output current determined depending on the temperature T of the switch 341.

[0030] As described above, according to this embodiment, the protection and control device 40 ＢＡＴ The current temperature T of the switch 341 is estimated from the cumulative value of the temperature change amount according to a predetermined temperature estimation function with a reference temperature T, and the upper limit value of the current flowing to the inverter circuit 20 is controlled according to the estimated temperature T, thereby suppressing excessive current from flowing to the switch 341 and preventing the switch 341 from burning or melting.

[0031] Second Embodiment This embodiment is a modification of the above embodiment, and the temperature of the high-voltage component (protected component temperature T ＴＧＴ ) is estimated based on the measured battery temperature, the temperature of the intervening component (intervening component temperature) to which the heat generated in the protected component is transferred is estimated, and the heat dissipation amount of the protected component in the temperature estimation function is calculated based on the estimated intervening component temperature.

[0032] In the present disclosure, the intervening component 344 is a component that is interposed between the switch 341, which is the component to be protected, and the battery 32, which is the object of measurement of the reference temperature. The intervening component 344 can transfer heat generated in the switch 341 due to current flowing when the battery 32 is charged or discharged, to the battery 32. In this embodiment, the intervening component 344 is a so-called bus bar that electrically connects the switch 341 and the terminals of the battery 32 (see FIG. 1 ).

[0033] 4 is a diagram showing an example of a functional model of a protection control device according to an embodiment of the present invention. As shown in the figure, the protection control device 40 of this embodiment includes, for example, a reference temperature acquisition unit 410, a protected component temperature estimation unit 420, a current limiting unit 430, and an intervening component temperature estimation unit 440. That is, the protection control device 40 of this embodiment differs from the protection control device 40 of the first embodiment described above in that it includes the intervening component temperature estimation unit 440. In this disclosure, the intervening component temperature estimation unit 440 corresponds to a second temperature estimation unit. Below, descriptions of parts that are the same as those in the first embodiment will be omitted as appropriate.

[0034] The protected component temperature estimator 420 calculates the temperature change amount ΔT / Δt of the switch 341 over time according to the first temperature estimation function, as described above, and estimates the current temperature T of the switch 341 based on the accumulated value of the calculated temperature change amount ΔT / Δt. In this embodiment, the first temperature estimation function of the protected component temperature estimator 420 is the temperature of the intervening component 344 (intervening component temperature T ＩＴＰ ) is used as the reference temperature.

[0035] That is, in this embodiment, the first temperature estimation function is defined as follows: ...Equation (3) where r is the thermal resistance [Ω] of the switch 341, I is the current [A] flowing through the switch 341, and C ｐ is the heat capacity of the switch 341 [J / K], A is the surface area of ​​the switch 341 [m ２ ], and h is the thermal conductivity of the switch 341 [W / (m ２ *K)]. Also, T ＴＧＴis the current temperature of the switch 341, T ＩＴＰ is the temperature of the intervening part 344 (intervening part temperature), a is the heat generation coefficient (first heat generation coefficient), and b is the heat dissipation coefficient (second heat dissipation coefficient).

[0036] As can be seen from the above equation, in this embodiment, it is assumed that the heat of the switch 341 is primarily transferred to the intervening component 344, and the heat dissipation temperature in the heat dissipation term of the first temperature estimation function shown in equation (3) is set to the intervening component temperature T ＩＴＰ The protected component temperature estimation unit 420 estimates the protected component temperature T ＴＧＴ is stored in a register (not shown) and output to the current limiting unit 430. ＴＧＴ The next temperature T ＴＧＴ It is used to estimate.

[0037] The interposed component temperature estimation unit 440 calculates the amount of temperature change over time of the interposed component 344 according to the second temperature estimation function, and calculates the current temperature T ＩＴＰ Estimate.

[0038] The second temperature estimation function is defined as follows: ...Equation (4) where r is the thermal resistance [Ω] of the intervening part 344, I is the current [A] flowing through the intervening part 344, and C ｐ is the heat capacity of the intervening part 344 [J / K], A is the surface area of ​​the intervening part 344 [m ２ ], and h is the thermal conductivity of the intervening part 344 [W / (m ２ *K)]. Also, T ＩＴＰ is the current temperature of the intervening part 344, T ＢＡＴ is the battery temperature. Although not shown in the equation, the heat generation term and the heat dissipation term may include the heat generation coefficient a' (second heat generation coefficient) and the heat dissipation coefficient b' (second heat dissipation coefficient) as described above.

[0039] As can be seen from the above equation, assuming that the heat of the interposed part 344 is transferred to the battery 32, the temperature of the heat transfer destination in the heat transfer term of the second temperature estimation function shown in equation (4) is the battery temperature T ＢＡＴThe interposed component temperature estimation unit 440 estimates the interposed component temperature T ＩＴＰ is stored in a register (not shown) and output to the protected component temperature estimation unit 420. ＩＴＰ is the next intervening part temperature T ＩＴＰ This allows the protected component temperature estimation unit 420 to estimate the estimated intervening component temperature T ＩＴＰ is the reference temperature, and the temperature of the protected part T ＴＧＴ Estimate.

[0040] The second heat generation coefficient a′ and / or the second heat dissipation coefficient b′ may also be dynamically adjusted, for example, according to the value of the current flowing through the switch 341. Alternatively, the second heat generation coefficient a′ and / or the second heat dissipation coefficient b′ may be dynamically adjusted according to, for example, the accumulated value of the temperature change amount ΔT / Δt, the battery temperature T ＢＡＴ , and / or may be dynamically adjusted in accordance with the environmental temperature measured by an environmental sensor (not shown). The coefficient adjustment unit (not shown) of the protection and control device 40 may be dynamically adjusted in accordance with, for example, the current value, the accumulated value of the temperature change ΔT / Δt, the battery temperature T ＢＡＴ and / or the second heat generation coefficient a' and / or the second heat dissipation coefficient b' are adjusted in accordance with the environmental temperature measured by the environmental sensor, thereby enabling more accurate temperature estimation for the high-voltage component 34 (switch 341) and protecting the switch 341 from overheating without excessively limiting the output of current.

[0041] As described above, according to this embodiment, the protection and control device 40 first calculates the battery temperature T ＢＡＴ The intervening component temperature T ＩＴＰ Then, the estimated intervening part temperature T ＩＴＰ The temperature T of the switch 341 is estimated according to the first temperature estimation function with the reference temperature T ＴＧＴ This allows the temperature of the protected component T ＴＧＴSince the upper limit of the current flowing through the inverter circuit 20 is controlled in accordance with the voltage, an excessive current is prevented from flowing through the switch 341, and the switch 341 can be prevented from being burned or melted.

[0042] <Third embodiment> This embodiment is a modification of the above embodiment, and is characterized in that, when estimating the temperature of a high-voltage component (protected component temperature), an initial value of the protected component temperature at the time the vehicle enters an active state is calculated based on the protected component temperature estimated immediately before the vehicle enters a sleep state, the duration of the sleep state, and the current battery temperature.

[0043] For example, as shown in Figure 5(a), the protected components generate heat due to the current flowing from the battery 32 while the vehicle is running (or flowing to the battery 32 while charging), and the temperature of the protected components gradually rises if the amount of heat generated is greater than the amount of heat dissipated.However, when the vehicle stops and the battery 32, protection control device 40, etc. enter a sleep state, it becomes impossible to estimate the temperature using the current.Therefore, when the protection control device 40 subsequently enters an active state again, for example, the temperature T ＢＡＴ is used as the reference temperature to calculate the temperature T ＴＧＴ Therefore, in this embodiment, the temperature of the protected component calculated immediately before the protection and control device 40 goes into the sleep state, the duration of the sleep state, and the current temperature T of the battery 32 are calculated. ＢＡＴ Based on this, the temperature T ＴＧＴ Calculate the initial value of and apply it to the temperature estimation function.

[0044] 6 is a diagram showing an example of a functional model of a protection and control device according to one embodiment of the present invention. As shown in the figure, the protection and control device 40 of this embodiment includes, for example, a reference temperature acquisition unit 410, a protected component temperature estimation unit 420, an intervening component temperature estimation unit 440, a current limiting unit 430, and an initial temperature calculation unit 450. That is, the protection and control device 40 of this embodiment differs from the protection and control device 40 of the second embodiment described above in that it includes the initial temperature calculation unit 450. In the following, descriptions of the same parts as those in the above embodiment will be omitted as appropriate.

[0045] In the figure, an initial temperature calculation unit 450 calculates the initial temperature T ｉｎｉ That is, the initial temperature calculation unit 450 calculates the initial temperature T ｉｎｉ When starting the estimation, the temperature T ＴＧＴ and a sleep time t indicating the time during which the protection and control device 40 was in a sleep state. Ｓｌｅｅｐ and battery temperature T ＢＡＴ Based on this, the initial temperature T of the switch 341 is calculated according to the initial temperature calculation function. ｉｎｉ＿ＳＷ The sleep time t is calculated using time information acquired from an on-board control device (not shown), for example.

[0046] In this embodiment, the initial temperature calculation function is defined as follows: ...Equation (5) where T ＢＡＴ is the battery temperature, T ＴＧＴ０ is the temperature of the switch 341 calculated immediately before the protection and control device 40 goes into the sleep state, t Ｓｌｅｅｐ is the sleep time, and τ is a predetermined time constant.

[0047] When the power system 1 is started, the initial temperature calculation unit 450 acquires the temperature of the protected component stored in the register and the battery temperature from the battery management system BMS, and further acquires the sleep time t Ｓｌｅｅｐ and calculate the initial temperature T according to the above initial temperature calculation function. ｉｎｉ＿ＳＷ and outputs this to the protected component temperature estimation unit 420. As a result, even when the protection and control device 40 changes from the sleep state to the active state, as shown in FIG. 7(b), for example, the protected component temperature estimation unit 420 can estimate the initial protected component temperature T ｉｎｉ＿ＳＷ is used to more accurately determine the temperature T ＴＧＴ It becomes possible to estimate the following.

[0048] The initial temperature calculation unit 450 calculates the initial temperature of the intervening component 344 after the power system 1 is started (intervening component initial temperature T ｉｎｉ＿ＩＴＰ ) may be calculated. ｉｎｉ＿ＩＴＰFor example, in the above-mentioned initial temperature calculation function, T ＴＧＴ０ Instead, the temperature T of the intervening part 344 immediately before the protection and control device 40 goes into the sleep state is ＩＴＰ０ The initial temperature calculation unit 450 calculates the initial temperature T ｉｎｉ＿ＩＴＰ to the intervening component temperature estimating unit 440. As a result, even when the protection and control device 40 changes from the sleep state to the active state, the intervening component temperature estimating unit 440 can estimate the intervening component initial temperature T ｉｎｉ＿ＩＴＰ Using this, the intervening part temperature T ＩＴＰ Therefore, the protected component temperature estimation unit 420 estimates the protected component temperature T ＴＧＴ can be estimated more accurately.

[0049] As described above, according to this embodiment, when the protection and control device 40 goes into a sleep state and then goes into an active state, the protection and control device 40 calculates the temperature T ＴＧＴ０ and the sleep time t and the current battery temperature T ＢＡＴ Based on this, the temperature T of the protected component at the time when the protection and control device 40 becomes active is calculated. ＴＧＴ The initial temperature of the switch 341 is calculated and used in a predetermined temperature estimation function. ＴＧＴ Similarly, the protection and control device 40 can estimate the estimated intervening component temperature T just before entering the sleep state. ＩＴＰ０ and the sleep time t and the current battery temperature T ＢＡＴ Based on this, the temperature T of the protected component at the time when the protection and control device 40 becomes active is calculated. ＴＧＴ The initial temperature of the switch 341 is calculated and used in a predetermined temperature estimation function. ＴＧＴ The temperature T of the intervening part 344 for estimating ＩＴＰ The temperature of the protected component T ＴＧＴSince the upper limit of the current flowing through the inverter circuit 20 is controlled in accordance with the voltage, an excessive current is prevented from flowing through the switch 341, and the switch 341 can be prevented from being burned or melted.

[0050] <Fourth embodiment> This embodiment is a modification of the above embodiment, and is characterized in that the temperature of the protected component is estimated using a predetermined temperature estimation function configured in multiple stages based on the structural relationship of the intervening components between the battery and the high-voltage component to be protected.

[0051] 7 is a diagram showing an example of a functional model of a protection control device according to one embodiment of the present invention. As shown in the figure, the protection control device 40 of this embodiment includes, for example, a reference temperature acquisition unit 410, a protected component temperature estimation unit 420, a current limiting unit 430, a first intervening component temperature estimation unit 440a, and a second intervening component temperature estimation unit 440b. That is, the protection control device 40 of this embodiment differs from the protection control device 40 of the above embodiment in that it includes multiple intervening component temperature estimation units 440. Below, descriptions of parts that are the same as those in the above embodiment will be omitted as appropriate.

[0052] In the figure, the first intervening component temperature estimating unit 440a and the second intervening component temperature estimating unit 440b are basically the same as the intervening component temperature estimating unit 440 shown in the above embodiment, but the coefficients of the temperature estimation function differ depending on the component or part to be subjected to temperature estimation. In this example, the second intervening component temperature estimating unit 440b estimates the battery temperature T ＢＡＴ The intervening part temperature T ＩＴＰ２ Then, the first intervening component temperature estimator 440a estimates the estimated intervening component temperature T ＩＴＰ２ The intervening part temperature T ＩＴＰ１ Then, the protected component temperature estimation unit 420 estimates the estimated intervening component temperature T ＩＴＰ１ The temperature T of the switch 341 is estimated according to a temperature estimation function with a reference temperature T = 1 , and is output to the current limiting unit 430 .

[0053] As described above, when the protection and control device 40 enters a sleep state and then enters an active state, the initial temperature calculation unit 450 calculates the initial temperature of each component or part to be subjected to temperature estimation and outputs the calculated temperature to the corresponding temperature estimation unit.

[0054] As described above, according to this embodiment, the protection and control device 40 uses a predetermined temperature estimation function configured in multiple stages, taking into account the structural relationship between the battery 32 and the switch 341. ＴＧＴ This allows the estimated temperature T ＴＧＴ Since the upper limit of the current flowing to the inverter circuit 20 via the switch 341 is controlled according to the voltage, excessive current is prevented from flowing to the switch 341, and the switch 341 can be prevented from burning or melting.

[0055] <Fifth embodiment> This embodiment is a modification of the above embodiment, and is characterized in that when estimating the temperature of the protected component (protected component temperature), the temperature of the protected component (protected component temperature) is estimated based on temperatures measured for other related high-voltage components (related high-voltage components).

[0056] As described above, the temperature of the switch 341, which is the target of temperature estimation, is structurally difficult to actually measure using a temperature sensor, so it is estimated according to a predetermined temperature estimation function that uses the temperature of the battery 32, whose temperature can be measured, as a reference temperature. On the other hand, some of the other related high-voltage components 34 around the switch 341 are structurally capable of actually measuring their temperatures using a temperature sensor. Therefore, in this embodiment, when estimating the temperature T of the switch 341, the battery temperature T ＢＡＴ Instead, the temperatures of the other high electric power components 34 are estimated according to a predetermined temperature estimation function that uses the temperature of the related high electric power component 34 measured by the temperature sensor S as a reference temperature, and the temperature of the protected component is estimated based on the estimated related high electric power component temperature. For example, the relay 342 is an example of the other related high electric power component 34.

[0057] FIG. 8 is a diagram showing an example of a functional model of a protection and control device according to one embodiment of the present invention. As shown in the figure, the protection and control device 40 of this embodiment includes, for example, a reference temperature acquisition unit 410, a protected component temperature estimation unit 420, a current limiting unit 430, and an intervening component temperature estimation unit 440. That is, the protection and control device 40 of this embodiment is the same as that of the above-described embodiment, except that the reference temperature acquisition unit 410 acquires the temperatures of other related high-voltage components 34 measured by a temperature sensor S. In the figure, the protection and control device 40 of this embodiment is shown as a modified example of the protection and control device 40 (see FIG. 4) shown in the second embodiment. However, the present invention is not limited to this and may be a modified version of the protection and control device 40 shown in the other embodiments.

[0058] As described above, according to this embodiment, the protection control device 40 estimates the current temperature T of the switch 341 from the cumulative value of the temperature change amount in accordance with a predetermined temperature estimation function that uses the temperature of the related high-voltage component as the reference temperature, and controls the upper limit value of the current flowing to the inverter circuit 20 in accordance with the estimated temperature T, thereby suppressing excessive current from flowing to the switch 341 and preventing the switch 341 from burning or melting.

[0059] The above-described embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be embodied in various forms without departing from the spirit of the present invention.

[0060] For example, in the methods disclosed herein, steps, operations, or functions may be performed in parallel or in a different order unless the results are inconsistent. The steps, operations, and functions described are provided merely as examples, and some of the steps, operations, and functions may be omitted or combined into one, or other steps, operations, or functions may be added, without departing from the spirit of the invention.

[0061] Furthermore, although various embodiments are disclosed in this specification, specific features (technical matters) in one embodiment can be added to or substituted for specific features in other embodiments, with appropriate modifications, and such forms are also included in the spirit of the present invention.

[0062] DESCRIPTION OF SYMBOLS 1...Power system 10...Motor 20...Inverter circuit 30...Battery pack 32...Battery 34...High-voltage component 341...Switch 342...Relay 343...Fuse 344...Intervening component 40...Protection and control device 410...Reference temperature acquisition unit 420...Protected component temperature estimation unit 430...Current limiting unit 431...Mapping table 440...Intervening component temperature estimation unit 450...Initial temperature calculation unit S...Temperature sensor

Claims

1. A protection control device that protects a high-voltage component electrically connected to a battery from overtemperature, a reference temperature acquisition unit that acquires, as a reference temperature, a temperature measured for a first component to which heat generated in the high voltage component due to a current flowing through the high voltage component is transferred; a first temperature estimation unit that estimates the temperature of the high voltage component as a temperature of the component to be protected; a current control unit that controls a current flowing through the high-voltage component based on the estimated temperature of the protected component, the first component to which heat generated in the high-voltage component is transferred is the battery; the first temperature estimation unit estimates the temperature of the protected component based on a cumulative value of a time-varying temperature difference between the heat generation amount of the high voltage component calculated based on the current and the heat dissipation amount of the high voltage component calculated based on the reference temperature in accordance with a first temperature estimation function; Protection and control equipment.

2. the first temperature estimation function includes a first heat generation coefficient and a first heat dissipation coefficient; a coefficient adjusting unit that adjusts the first heat generation coefficient and the first heat dissipation coefficient according to the value of the current flowing through the high-voltage component; A protection and control device according to claim 1.

3. the first temperature estimator adjusts the first heat generation coefficient and the first heat dissipation coefficient in accordance with the accumulated value, the reference temperature, and an environmental temperature output by an environmental sensor. A protection and control device as claimed in claim 2.

4. a second temperature estimator configured to estimate, as an intermediate component temperature, a temperature of an intermediate component that is interposed between the battery and the high-voltage component and to which heat generated in the high-voltage component is transferred; the second temperature estimator estimates the temperature of the intervening component based on a cumulative value of a time-varying temperature difference between the heat generation amount calculated based on the current and the heat radiation amount of the intervening component calculated based on the reference temperature in accordance with a second temperature estimation function; the first temperature estimation unit calculates the heat radiation amount of the high voltage component based on the estimated temperature of the interposed component. A protection and control device according to claim 1.

5. an initial temperature calculation unit that calculates an initial temperature of the protected component temperature; The initial temperature calculation unit When starting to estimate the temperature of the protected component, the initial temperature is calculated based on a sleep time indicating the time during which the protection control device was in a sleep state, the temperature of the unprotected component calculated immediately before the protection control device went into a sleep state, and the temperature of the battery. The protection and control device according to claim 4.

6. a plurality of the second temperature estimation units; each of the plurality of second temperature estimators calculates the heat generation amount and the heat radiation amount of the intervening component in accordance with the second temperature estimation function based on a structural relationship of the intervening component between the battery and the high voltage component; The protection and control device according to claim 4.

7. the second temperature estimation function includes a second heat generation coefficient and a second heat dissipation coefficient; a coefficient adjusting unit that adjusts the second heat generation coefficient and the second heat dissipation coefficient according to the value of the current flowing through the high-voltage component, The protection and control device according to claim 4.

8. the coefficient adjustment unit adjusts the second heat generation coefficient and the second heat dissipation coefficient in accordance with the accumulated value, the reference temperature, and an environmental temperature output by an environmental sensor. A protection and control device according to claim 7.

9. the first component to which heat generated in the high-voltage component is conducted includes other related high-voltage components other than the battery; The protection and control device according to claim 4.

10. A current control method using a protection control device that controls a current flowing through a high-voltage component due to charging and discharging of a battery, acquiring, as a reference temperature, a temperature measured with respect to the battery to which heat generated in the high-voltage component due to a current flowing through the high-voltage component is transferred; estimating the temperature of the high voltage component as a temperature of the component to be protected; and controlling a current flowing through the high-voltage component based on the estimated temperature of the protected component; Estimating the temperature of the high voltage component as the protected component temperature includes estimating the protected component temperature based on a cumulative value of a time-varying temperature change of a difference between a heat generation amount of the high voltage component calculated based on the current and a heat dissipation amount of the high voltage component calculated based on the reference temperature in accordance with a first temperature estimation function. Current control method.