Method and device for estimating junction temperature of power device through thermal resistance parameter compensation

Abstract

The invention discloses a method and device for estimating the junction temperature of a power device through thermal resistance parameter compensation, and the method comprises the steps: calculating the power loss value of the power device according to the operation condition of an electric vehicle cooling system, inputting the power loss value into a thermal resistance model, and obtaining a power consumption thermal resistance parameter value; cooling liquid flow is obtained, and a thermal resistance parameter compensation value is calibrated according to the cooling liquid flow; performing junction temperature estimation on the power device according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value; the invention provides a heat management strategy of a variable cooling condition, and the power consumption of the water pump can be reduced; meanwhile, the current cooling flow can be reversely identified by calculating the loss power and the temperature reported by the NTC / PTC temperature sensor and the like during the operation of the system under the strategy, so that the junction temperature estimation of the power module of the motor controller is compensated, the junction temperature estimation precision is improved, the estimation temperature deviation is reduced, and the reliability of the system is improved. And more reliable temperature protection is provided for a motor controller system.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicle cooling, and in particular to a method and device for estimating the junction temperature of a power device through thermal resistance parameter compensation. Background Art

[0002] With the rapid development of the new energy vehicle industry, power devices in electric vehicle power systems are becoming increasingly important. In order to ensure the reliability and safety of electric vehicles, it is necessary to estimate the junction temperature of power devices to avoid device damage and performance degradation caused by excessive temperature. At the same time, junction temperature estimation can also evaluate the fatigue aging of devices under different working conditions, further improving the reliability and life of devices.

[0003] In practical applications, in order to reduce the noise and power consumption of the cooling water pump, the cooling flow is usually graded. When the cooling zone is in low demand, the cooling flow is reduced to achieve the effect of reducing noise and power consumption. However, the change in cooling flow will affect the thermal resistance in the junction temperature estimation, resulting in poor junction temperature estimation accuracy and affecting the temperature protection effect. The above problems need to be solved urgently. Summary of the invention

[0004] The object of the present invention is to provide a method and device for estimating the junction temperature of a power device through thermal resistance parameter compensation, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for estimating the junction temperature of a power device by thermal resistance parameter compensation, comprising:

[0006] Calculate the power loss value of the power device according to the operating conditions of the electric vehicle cooling system, input the power loss value into the thermal resistance model, and obtain the power consumption thermal resistance parameter value;

[0007] Obtain the coolant flow rate, and calibrate the thermal resistance parameter compensation value according to the coolant flow rate;

[0008] The junction temperature of the power device is estimated based on the power dissipation thermal resistance parameter value and the thermal resistance parameter compensation value.

[0009] Furthermore, the power loss value of the power device is calculated according to the operating condition of the electric vehicle cooling system, and further includes:

[0010] The calculation formula of power device conduction loss is:

[0011]

[0012] The calculation formula for power device switching loss is:

[0013]

[0014] The power loss calculation formula of power device is:

[0015] P total =P cond +P sw ——Formula (3);

[0016] Where, T sw is the switching cycle of the power device, V ce (t) is the saturation voltage of the power device when it is turned on, I c (t) is the collector current when the power device is turned on and switched, V cc (t) is the collector-emitter voltage during the switching process of the power device.

[0017] Furthermore, the coolant flow rate is obtained, including:

[0018] A plurality of continuous initial temperature intervals of the coolant are set, and a plurality of coolant flow intervals are correspondingly obtained according to the plurality of continuous initial temperature intervals, wherein the initial temperature is the temperature of the coolant when the power loss value of the power device is zero.

[0019] Further, collecting device temperature of the power device;

[0020] Through experimental test data, the coolant flow rate corresponding to the device temperature and power loss is obtained;

[0021] A power loss, device temperature and coolant flow relationship table is generated according to the set multiple continuous initial temperature intervals, coolant flow intervals, device temperature and power loss.

[0022] Further, the thermal resistance parameter compensation value is calibrated according to the coolant flow rate, which is characterized by comprising:

[0023] Based on the relationship table between power loss, device temperature and coolant flow rate, calibrate the thermal resistance parameter compensation value corresponding to the coolant flow rate;

[0024] The junction temperature of the power device is estimated based on the power dissipation thermal resistance parameter value and the thermal resistance parameter compensation value.

[0025] On the other hand, a device for estimating the junction temperature of a power device by using thermal resistance parameter compensation is provided, and the method for estimating the junction temperature of a power device by using thermal resistance parameter compensation as described in any one of the above items is applied, comprising:

[0026] A calculation module, used to calculate the power loss value of the power device according to the operating conditions of the electric vehicle cooling system, input the power loss value into the thermal resistance model, and obtain the power consumption thermal resistance parameter value;

[0027] A processing module, used for obtaining the coolant flow rate and calibrating the thermal resistance parameter compensation value according to the coolant flow rate;

[0028] The estimation module is used to estimate the junction temperature of the power device according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value.

[0029] Furthermore, the processing module also includes:

[0030] The setting module is used to set multiple continuous initial temperature intervals of the coolant, and obtain multiple coolant flow intervals according to the multiple continuous initial temperature intervals, wherein the initial temperature is the temperature of the coolant when the power loss value of the power device is zero.

[0031] Furthermore, the processing module includes:

[0032] A generation module is used to collect the device temperature of the power device; obtain the coolant flow corresponding to the device temperature and power loss through experimental test data; and generate a power loss, device temperature and coolant flow relationship table according to multiple set continuous initial temperature intervals, coolant flow intervals, device temperature and power loss.

[0033] In another aspect, an electronic device is provided, the electronic device comprising:

[0034] one or more processors;

[0035] a storage device for storing one or more programs,

[0036] When the one or more programs are executed by the one or more processors, the one or more processors implement any of the above-described methods for estimating the junction temperature of a power device through thermal resistance parameter compensation.

[0037] On the other hand, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that when the program is executed by a processor, a method for estimating the junction temperature of a power device by thermal resistance parameter compensation as described above is implemented.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention proposes a method for determining parameters of a cooling flow grading strategy, through which a thermal management strategy with variable cooling conditions is implemented, which can reduce the power consumption of the water pump; at the same time, under this strategy, by calculating the power loss and the temperature reported by temperature sensors such as NTC / PTC when the system is running, the current cooling flow can be reversely identified, thereby compensating for the junction temperature estimation of the motor controller power module, improving the junction temperature estimation accuracy, reducing the estimated temperature deviation, and providing more reliable temperature protection for the motor controller system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a method for estimating the junction temperature of a power device by thermal resistance parameter compensation in an embodiment of the present invention;

[0040] Figure 2 A connection block diagram of a device for estimating junction temperature of a power device through thermal resistance parameter compensation in an embodiment of the present invention;

[0041] Figure 3 Schematic diagram showing the relationship between power loss, device temperature and coolant flow rate in an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the connection structure of an electronic device and a computer-readable storage medium in an embodiment of the present invention;

[0043] In the figure: 10, memory; 11, processor; 12, communication bus; 13, communication interface; 14, computer program; 15, storage medium; 16, calculation module; 17, processing module; 18, estimation module. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] Please refer to the attached drawings of the specification, the present invention provides a technical solution: a method for estimating the junction temperature of a power device by thermal resistance parameter compensation, comprising the following steps:

[0048] S102, calculating the power loss value of the power device according to the operating condition of the electric vehicle cooling system, inputting the power loss value into the thermal resistance model, and obtaining the power consumption thermal resistance parameter value;

[0049] Specifically, the power loss value of the power device is calculated according to the operating conditions of the electric vehicle cooling system, and also includes:

[0050] The calculation formula of power device conduction loss is:

[0051]

[0052] The calculation formula for power device switching loss is:

[0053]

[0054] The power loss calculation formula of power device is:

[0055] P total =P cond +P sw ——Formula (3);

[0056] Where, T sw is the switching cycle of the power device, V ce (t) is the saturation voltage of the power device when it is turned on, I c (t) is the collector current when the power device is turned on and switched, V cc (t) is the collector-emitter voltage during the switching process of the power device.

[0057] Among them, the power device loss mainly includes the conduction loss and switching loss of IGBT or MOSFET, the conduction loss and reverse recovery loss of the diode. According to different calculation methods, it is mainly conduction loss and switching loss (the reverse recovery loss of the diode can be considered as its turn-off loss). These losses directly affect the chip junction temperature of the power device.

[0058] S104, obtaining the coolant flow rate, and calibrating the thermal resistance parameter compensation value according to the coolant flow rate;

[0059] Among them, the loss estimation model parameters need to be calibrated during the estimation process to accurately calculate the device loss and obtain the junction temperature.

[0060] Specifically, obtaining the coolant flow rate includes:

[0061] A plurality of continuous initial temperature intervals of the coolant are set, and a plurality of coolant flow intervals are correspondingly obtained according to the plurality of continuous initial temperature intervals, wherein the initial temperature is the temperature of the coolant when the power loss value of the power device is zero.

[0062] In the above embodiment, an electric vehicle cooling flow classification strategy is used as an example. The strategy uses the coolant temperature as the classification flow reference, sets three classification reference temperatures, and divides four continuous initial temperature intervals. The initial temperatures are, respectively, T A , T B , T C , where T A >T B >T C The corresponding coolant flow rates are Q A , Q B , Q C , divided into four coolant flow intervals, where Q A >Q B >Q C , set the initial coolant temperature to T A At this time, the device temperature measured is the initial temperature of the NTC, which is also T A , the coolant flow rate is Q A ; Set the initial coolant temperature to T B , at this time the initial temperature of NTC is also T B , the coolant flow rate is Q B ; Set the initial coolant temperature to T C , at this time the initial temperature of NTC is also T C , the coolant flow rate is Q C .

[0063] Specifically, collecting device temperature of power devices;

[0064] Through experimental test data, the coolant flow rate corresponding to the device temperature and power loss is obtained;

[0065] A power loss, device temperature and coolant flow relationship table is generated according to the set multiple continuous initial temperature intervals, coolant flow intervals, device temperature and power loss.

[0066] Meanwhile, we set the device temperature of the power device as the NTC temperature, and the relationship between the NTC temperature and the coolant temperature. The coolant temperature can also be calculated using the calculated power device loss and the sampled NTC temperature.

[0067] like Figure 3 As shown, in the embodiment of the present invention, the test process is set according to the corresponding working conditions and data is collected; the influence of temperature on the power module loss is ignored, and the maximum power module loss is P max , measure P max Under the corresponding working conditions, at the coolant temperature T A , cooling flow Q A NTC temperature T NTCA , at the coolant temperature TB , cooling flow Q B NTC temperature T NTCB , at the coolant temperature T C , cooling flow Q C NTC temperature T NTCC ; Determine T A , T B , T C After that, test 0, 25%·P max , 50%·P max 、75%·P max 、100%·P max The NTC temperature under different cooling conditions under the corresponding working conditions generates a relationship table between power loss, device temperature and coolant flow.

[0068] The junction temperature of the power device is estimated based on the power dissipation thermal resistance parameter value and the thermal resistance parameter compensation value.

[0069] Specifically, based on the relationship table of power loss, device temperature and coolant flow rate, the thermal resistance parameter compensation value corresponding to the coolant flow rate is calibrated; and the junction temperature of the power device is estimated according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value.

[0070] Among them, the thermal resistance parameter compensation value corresponding to the coolant flow rate is calibrated according to the test calibration, which can be set as the compensation coefficient of the power consumption thermal resistance parameter value. The power consumption thermal resistance parameter value is adjusted according to the change of the calibrated compensation coefficient, and the thermal resistance parameter in the junction temperature estimation model is compensated to improve the junction temperature estimation accuracy.

[0071] The power module temperature sensors applicable to the present invention include but are not limited to NTC, PTC, and diodes; the power module types applicable to the present invention include but are not limited to IGBT and MOSFET; the power electronic topologies applicable to the method include but are not limited to DC-DC, DC-AC, AC-DC, etc.

[0072] S106 , estimating the junction temperature of the power device according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value.

[0073] On the other hand, a device for estimating the junction temperature of a power device by using thermal resistance parameter compensation is provided, and the method for estimating the junction temperature of a power device by using thermal resistance parameter compensation as described in any one of the above items is applied, comprising:

[0074] A calculation module 16 is used to calculate the power loss value of the power device according to the operating conditions of the electric vehicle cooling system, input the power loss value into the thermal resistance model, and obtain the power consumption thermal resistance parameter value;

[0075] Among them, the power loss value of the power device is calculated according to the operating conditions of the electric vehicle cooling system, and also includes:

[0076] The calculation formula of power device conduction loss is:

[0077]

[0078] The calculation formula for power device switching loss is:

[0079]

[0080] The power loss calculation formula of power device is:

[0081] P total =P cond +P sw ——Formula (3);

[0082] Where, T sw is the switching cycle of the power device, V ce (t) is the saturation voltage of the power device when it is turned on, I c (t) is the collector current when the power device is turned on and switched, V cc (t) is the collector-emitter voltage during the switching process of the power device.

[0083] The processing module 17 is used to obtain the coolant flow rate and calibrate the thermal resistance parameter compensation value according to the coolant flow rate;

[0084] Optionally, the processing module 17 further includes:

[0085] The setting module is used to set multiple continuous initial temperature intervals of the coolant, and obtain multiple coolant flow intervals according to the multiple continuous initial temperature intervals, wherein the initial temperature is the temperature of the coolant when the power loss value of the power device is zero.

[0086] Optionally, the processing module includes:

[0087] A generation module is used to collect the device temperature of the power device; obtain the coolant flow corresponding to the device temperature and power loss through experimental test data; and generate a power loss, device temperature and coolant flow relationship table according to multiple set continuous initial temperature intervals, coolant flow intervals, device temperature and power loss.

[0088] The estimation module 18 is used to estimate the junction temperature of the power device according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value.

[0089] Among them, based on the relationship table of power loss, device temperature and coolant flow rate, the thermal resistance parameter compensation value corresponding to the coolant flow rate is calibrated; and the junction temperature of the power device is estimated according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value.

[0090] On the other hand, Figure 4As shown, an electronic device is provided, the electronic device comprising:

[0091] One or more processors 11;

[0092] a storage device for storing one or more programs,

[0093] When the one or more programs are executed by the one or more processors 11, the one or more processors 11 implement any of the above-mentioned methods for estimating the junction temperature of a power device through thermal resistance parameter compensation.

[0094] Specifically, the storage device is a memory 10, a processor (CPU) 11 and a computer program 14, the computer program 14 is stored in the memory 10, and the processor 11 executes the computer program 14 to implement any one of the above-mentioned methods for estimating the junction temperature of a power device through thermal resistance parameter compensation. The control system also includes: a communication interface 13 and a communication bus 12, the processor 11, the communication interface 13, and the memory 10 communicate through the communication bus 12, wherein the communication bus 12 is an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc., and if the memory 10, the processor 11 and the communication interface 13 are integrated on a chip, the memory 10, the processor 11 and the communication interface 13 can communicate with each other through an internal interface.

[0095] The processor 11 may also be a specific integrated circuit or multiple integrated circuits.

[0096] On the other hand, Figure 4 As shown, a computer-readable storage medium 15 is provided, on which a computer program 14 is stored. When the program is executed by a processor 11, a method for estimating the junction temperature of a power device by thermal resistance parameter compensation as described above is implemented.

[0097] Specifically, the computer program 14 may include a program code, which includes a computer operation instruction; a memory 10, which is used to store the computer program 14. The memory 10 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory; a communication interface 13, which is used to communicate with other devices such as a client or other servers.

[0098] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for estimating the junction temperature of a power device by thermal resistance parameter compensation, characterized in that: include: Calculate the power loss value of the power device according to the operating conditions of the electric vehicle cooling system, input the power loss value into the thermal resistance model, and obtain the power consumption thermal resistance parameter value; Obtain the coolant flow rate, and calibrate the thermal resistance parameter compensation value according to the coolant flow rate; The junction temperature of the power device is estimated based on the power dissipation thermal resistance parameter value and the thermal resistance parameter compensation value.

2. A method for estimating junction temperature of a power device by thermal resistance parameter compensation according to claim 1, characterized in that: Calculate the power loss value of the power device according to the operating conditions of the electric vehicle cooling system, including: The calculation formula of power device conduction loss is: The calculation formula for power device switching loss is: The power loss calculation formula of power device is: P total =P cond +P sw ——Formula (3); Where, T sw is the switching cycle of the power device, V ce (t) is the saturation voltage of the power device when it is turned on, I c (t) is the collector current when the power device is turned on and switched, V cc (t) is the collector-emitter voltage during the switching process of the power device.

3. The method for estimating the junction temperature of a power device by thermal resistance parameter compensation according to claim 1, characterized in that: Get coolant flow, including: A plurality of continuous initial temperature intervals of the coolant are set, and a plurality of coolant flow intervals are correspondingly obtained according to the plurality of continuous initial temperature intervals, wherein the initial temperature is the temperature of the coolant when the power loss value of the power device is zero.

4. The method for estimating the junction temperature of a power device by thermal resistance parameter compensation according to claim 3, characterized in that: include: Collect device temperature of power devices; Through experimental test data, the coolant flow rate corresponding to the device temperature and power loss is obtained; A power loss, device temperature and coolant flow relationship table is generated according to the set multiple continuous initial temperature intervals, coolant flow intervals, device temperature and power loss.

5. According to the method for estimating the junction temperature of a power device by thermal resistance parameter compensation according to claim 4, the thermal resistance parameter compensation value is calibrated according to the coolant flow rate, characterized in that: include: Based on the relationship table between power loss, device temperature and coolant flow rate, calibrate the thermal resistance parameter compensation value corresponding to the coolant flow rate; The junction temperature of the power device is estimated based on the power dissipation thermal resistance parameter value and the thermal resistance parameter compensation value.

6. A device for estimating the junction temperature of a power device by using thermal resistance parameter compensation, using a method for estimating the junction temperature of a power device by using thermal resistance parameter compensation as claimed in any one of claims 1 to 4, characterized in that: include: A calculation module, used to calculate the power loss value of the power device according to the operating conditions of the electric vehicle cooling system, input the power loss value into the thermal resistance model, and obtain the power consumption thermal resistance parameter value; A processing module, used for obtaining the coolant flow rate and calibrating the thermal resistance parameter compensation value according to the coolant flow rate; The estimation module is used to estimate the junction temperature of the power device according to the power consumption thermal resistance parameter value and the thermal resistance parameter compensation value.

7. The device for estimating junction temperature of a power device by thermal resistance parameter compensation according to claim 6, characterized in that: The processing module also includes: The setting module is used to set multiple continuous initial temperature intervals of the coolant, and obtain multiple coolant flow intervals according to the multiple continuous initial temperature intervals, wherein the initial temperature is the temperature of the coolant when the power loss value of the power device is zero.

8. The device for estimating junction temperature of a power device by thermal resistance parameter compensation according to claim 7, characterized in that: The processing modules include: The generation module is used to collect the device temperature of the power device; obtain the coolant flow corresponding to the device temperature and power loss through experimental test data; and generate a power loss, device temperature and coolant flow relationship table according to multiple set continuous initial temperature intervals, coolant flow intervals, device temperature and power loss.

9. An electronic device, characterized in that: The electronic device comprises: one or more processors; a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement a method for estimating the junction temperature of a power device by thermal resistance parameter compensation as described in any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, a method for estimating the junction temperature of a power device by thermal resistance parameter compensation as described in any one of claims 1 to 5 is implemented.

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