Electric drive system control method based on temperature calculation

Abstract

The invention belongs to the technical field of vehicle all-in-one electric driving systems, and particularly relates to an electric driving system control method based on temperature calculation. Wherein the electric driving system is composed of a plurality of electronic components and / or mechanical components serving as working nodes, and any working node can transfer heat with at least one other adjacent working node; the method comprises the following steps: calculating temperature data of each working node at the next moment according to a heat balance equation of the working nodes and temperature data of each working node at the current moment; wherein the temperature data of each working node at the current moment is calculated and obtained based on the initial temperature of the working node and the heat balance equation of the working node; and based on the real-time temperature data of one or more working nodes, a corresponding temperature protection strategy is adopted to control a motor in the electric driving system to work. According to the invention, the temperature of different electronic and mechanical parts in the electric drive system can be accurately detected, the actual cost is reduced, and the manufacturing process is simplified.

Description

Technical Field

[0001] The present invention belongs to the technical field of all-in-one electric drive systems for vehicles, and specifically relates to a control method for an electric drive system based on temperature calculation. Background Art

[0002] Taking the drive motor of new energy vehicles as an example, the higher the motor speed, torque density and power density, the higher the heat it generates. Therefore, the heat dissipation and cooling structure of the bridge are essential for the reliable, stable and efficient operation of the motor. The cooling of the bridge can be divided into air cooling, water cooling and oil cooling. Oil cooling is becoming the first choice for high-performance bridge cooling solutions due to its natural electrical insulation and high degree of freedom in structural design.

[0003] Compared with water-cooled bridges, the cooling oil of oil-cooled bridges can directly cool the heat-generating components of the bridge, with higher cooling efficiency, and is widely used in the field of new energy vehicles. However, the temperature of the oil-cooled bridge changes in real time during operation, and excessive temperature will affect the safety and life of the bridge. Therefore, the main method is to arrange temperature sensors on the bridge to monitor its temperature changes, but due to the influence of the cooling method, this method has a large detection error, which affects the performance output capacity of the motor. At the same time, arranging multiple temperature sensors on the bridge greatly increases the product cost and process complexity. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a temperature detection method that can avoid the deployment of a large number of temperature sensors and accurately detect the temperature changes of different electronic and mechanical components on the oil-cooled bridge with lower cost and simpler process complexity, so as to facilitate the regulation of the output performance of the motor.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a control method for an electric drive system based on temperature calculation, wherein the electric drive system is composed of a plurality of electronic components and / or mechanical components as working nodes, wherein any working node can transfer heat with at least one other adjacent working node; the method comprises: calculating the temperature data of each working node at the next moment according to the thermal balance equation of the working node and the temperature data of each working node at the current moment; wherein the temperature data of each working node at the current moment is obtained by calculation based on the initial temperature of the working node and its thermal balance equation; and adopting a corresponding temperature protection strategy based on the real-time temperature data of one or more working nodes to control the operation of the motor in the electric drive system.

[0006] According to a specific embodiment of the present invention, the electric drive system includes at least: a motor, a motor controller, a reducer, and a cooling module; wherein the motor controller is provided with a temperature sensor for detecting temperature changes, and a current sensor is provided for detecting current changes; the electronic components and / or mechanical components serving as working nodes include: motor windings, motor magnets, motor coolant, motor controller, motor controller coolant, reducer, heat exchanger, and radiator.

[0007] According to a specific embodiment of the present invention, the step of obtaining the initial temperature of the working node includes: after the electric drive system is powered on, calculating the initial temperature of the motor winding according to the resistance value of the motor winding; obtaining the initial temperature of the motor controller through the temperature sensor of the motor controller; and selecting the maximum value from the initial temperature of the motor winding and the initial temperature of the motor controller as the initial temperature of each node.

[0008] According to a specific embodiment of the present invention, the step of obtaining the resistance value of the motor winding includes: sending multiple short-time DC pulse voltages through the motor controller, and collecting the line current corresponding to the motor through the current sensor of the motor controller; calculating multiple resistance values ​​of the motor winding according to the short-time DC pulse voltage and the line current, and after removing the resistance values ​​calculated by the first and last short-time DC pulse voltages, taking the average of the remaining multiple resistance values ​​as the final resistance value of the motor winding.

[0009] According to a specific embodiment of the present invention, before obtaining the thermal balance equation, it also includes: fitting the thermal power value of each working node under different working conditions through preset test data, and building a corresponding database based on it; fitting the equivalent thermal resistance between adjacent working nodes and the equivalent thermal capacity of each working node through preset test data, and building a corresponding database based on them.

[0010] According to a specific embodiment of the present invention, the thermal balance equation is obtained as follows: for each working node, the product of the temperature rise rate between the current moment and the previous moment of the working node and the equivalent heat capacity corresponding to the working node is calculated as the first temperature change; the quotient of the temperature difference between the working node and the adjacent working node at the current moment and the equivalent thermal resistance between the working node and the adjacent working node is calculated as the second temperature change; based on the first temperature change, the second temperature change, and the thermal power value corresponding to the current working condition of the working node, an equation for energy conservation is established to form the thermal balance equation.

[0011] According to a specific embodiment of the present invention, the formula of the heat balance equation is as follows:

[0012]

[0013] in, represents the temperature of the nth working node at the i-th moment, Δt represents the time interval between the i-th moment and the i+1-th moment, It represents the temperature of the jth working node adjacent to the nth working node at the i-th moment, R j,n represents the equivalent thermal resistance between the nth working node and the jth adjacent working node, P n Represents the thermal power value of the nth working node, C n Represents the equivalent heat capacity of the nth working node.

[0014] According to a specific embodiment of the present invention, the step of obtaining the temperature data of the working node at the current moment includes: taking the time corresponding to the initial temperature of the working node as the initial moment, and calculating the temperature data of the working node at the next moment of the initial moment based on the thermal balance equation of the working node and the initial temperature of the adjacent working nodes; based on the working condition changes of the working node, calculating in chronological order to obtain the temperature data of the working node at the current moment.

[0015] According to a specific embodiment of the present invention, the step of taking a corresponding temperature protection strategy to control the operation of the motor based on the real-time temperature data of one or more working nodes includes: adjusting the output performance of the motor in the electric drive system according to the temperature data of the working node at the current moment.

[0016] According to a specific embodiment of the present invention, the method further includes: diagnosing whether the temperature data calculated by each working node is convergent and reliable.

[0017] According to a specific embodiment of the present invention, the step of diagnosing whether the temperature data of the working node converges reliably includes: identifying through the motor controller whether the electric drive system is currently operating in a high torque load condition range: if so, calculating the temperature rise rate of a specific working node based on the temperature data of each working node within the high torque load condition range, and comparing it with the standard value of the temperature rise rate under the same condition in a preset database to identify whether the temperature data currently calculated by the working node converges reliably.

[0018] The present invention provides a method for detecting the temperature of an oil-cooled bridge, which can reduce the layout cost of the temperature sensor, thereby reducing the process complexity of installing the temperature sensor on the oil-cooled bridge. The operating temperature of key electronic or mechanical components such as motor windings and magnetic steel can be obtained in real time during vehicle operation, so as to control the performance output of the motor accordingly and avoid temperature runaway, thereby improving the reliability of the oil-cooled bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A flow chart of a specific embodiment of a method for controlling an electric drive system based on temperature calculation provided by the present invention;

[0020] Figure 2 A flow chart of another specific embodiment of a method for controlling an electric drive system based on temperature calculation provided by the present invention;

[0021] Figure 3 A schematic diagram of the structure of a specific embodiment of an equivalent node network of an electric drive system provided by the present invention;

[0022] Figure 4 A waveform diagram of a specific embodiment of a short-time pulse voltage sent by a motor controller provided by the present invention;

[0023] Figure 5 A curve diagram of a specific embodiment of adjusting the output performance of a motor according to temperature changes provided by the present invention;

[0024] Figure 6 A schematic structural diagram of a specific embodiment of an electric drive system control system based on temperature calculation provided by the present invention;

[0025] Figure 7 The present invention provides a structural block diagram of a specific embodiment of an electronic device. DETAILED DESCRIPTION

[0026] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0027] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0028] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0029] First of all, it should be explained that in order to enable people in this technical field to better understand the present application scheme, the technical background of this application is explained accordingly.

[0030] It is understandable that the oil-cooled bridge is not only provided with a motor, but also with a corresponding water-cooling circuit and an oil-cooling circuit, as well as other electronic and mechanical components, such as a heat exchanger between the water-cooling circuit and the oil-cooling circuit, a reducer that cooperates with the motor mechanically, and a corresponding motor controller. In order to give full play to the performance of the oil-cooled bridge, it is necessary to monitor the temperature changes of different electronic and mechanical components when the oil-cooled motor is working, so as to adjust the performance release of the motor accordingly and make it work in the best state. In this embodiment, the electric drive system refers to the oil-cooled bridge. Of course, the electric drive system control method of the present application is not only applicable to oil-cooled bridges, but can also adapt to bridges with other cooling methods such as water-cooled bridges, and no excessive restrictions are made on this.

[0031] In addition, according to Kirchhoff's laws, we know that in a closed system, energy can neither be created nor destroyed, but can only be converted from one form to another, as well as the transfer process of energy in the system. Therefore, according to Kirchhoff's laws, energy in the system can be expressed in the form of heat regarding energy transfer. Further, according to Kirchhoff's laws, we know that when a thermodynamic system is in thermal equilibrium, the net inflow of heat is equal to zero. In other words, the heat absorbed by an object from another object is equal to the heat released by itself. This means that the transfer of heat within the system and between systems is balanced.

[0032] Based on the above, this embodiment proposes an electric drive system control method based on temperature calculation. Compared with arranging multiple temperature sensors on the oil-cooled electric bridge to detect the temperature, it can not only accurately calculate the temperature changes of different electronic and mechanical components to facilitate the regulation of the performance release of the motor, but also reduce unnecessary costs and reduce process complexity.

[0033] Example 1

[0034] See also Figure 1 , as shown in 2, a method for controlling an electric drive system based on temperature calculation, comprising:

[0035] Step S100, calculating the temperature data of each working node at the next moment according to the thermal balance equation of the working node and the temperature data of each working node at the current moment; wherein the temperature data of each working node at the current moment is calculated based on the initial temperature of the working node and its thermal balance equation.

[0036] Based on the above, it can be known that the oil-cooled bridge includes several electronic and / or mechanical components, such as motors, motor controllers, reducers, and cooling modules, and the following can be regarded as working nodes: motor windings, motor magnets, motor coolants, motor controllers, motor controller coolants, reducers, heat exchangers, and radiators. It can be understood that the electronic and / or mechanical components mentioned above are connected by at least one method that can transfer heat, such as transferring thermal power by electrical connection, or transferring heat by physical means, etc. It can be seen that the network composed of multiple different electronic and / or mechanical components that can be regarded as working nodes is equivalent to the oil-cooled bridge as a whole.

[0037] In a specific embodiment, reference may be made to Figure 3 The schematic diagram of the equivalent node network shown in FIG. 1 shows the temperature of the motor controller coolant, node 2 shows the junction temperature of the field effect tube (MOS tube or IGBT tube) in the motor controller, node 3 shows the temperature of the heat exchanger, node 4 shows the temperature of the radiator, node 5 shows the temperature of the motor coolant (such as cooling oil), node 6 shows the temperature of the motor winding, node 7 shows the temperature of the motor magnetic steel, and node 8 shows the temperature of the reduction box.

[0038] It should be noted that Figure 3 The schematic diagram of the oil-cooled bridge equivalent node network shown is for reference only. In actual applications, due to the differences between different oil-cooled motors, the electronic and mechanical components therein are correspondingly different, and working nodes can be added / deleted accordingly. Without departing from the spirit of the present invention, modifications and embellishments made to the embodiments of the present invention by those skilled in the art still fall within the scope of the invention application of the present invention.

[0039] Further, how to obtain the heat balance equation between a working node and its adjacent working nodes can be referred to as follows:

[0040] First, the thermal power values ​​of each working node of the oil-cooled bridge under different working conditions can be fitted through preset test data. Specifically, since the working parameters of the oil-cooled bridge under different working conditions will be different, for example, the values ​​of parameters such as speed, torque, bus voltage, etc. will be adjusted before and after the working conditions change. Therefore, the working parameters of the oil-cooled bridge under different working conditions can be pre-planned, and the heating power of each working node under the working condition can be calculated based on the preset working parameters of the oil-cooled bridge under a working condition, that is, the thermal power value, so as to construct a database of thermal power values ​​of each working node under different working conditions, so that the thermal power value of each working node can be obtained according to the current working condition of the oil-cooled bridge. For example, the thermal power value of a certain working node in the oil-cooled bridge under a certain working condition can be extracted from the database, and the temperature data of the working node at this moment can be calculated based on the thermal power value.

[0041] It should be added here that any working condition of the oil-cooled motor may last for a certain period of time, and the components in the oil-cooled bridge will still cause some losses during the period of a working condition, which will cause the thermal power value of a working node to change over time. Therefore, it is also necessary to fit the thermal power values ​​of each working node that change over time under the same working condition to build a complete database.

[0042] Secondly, based on the thermal power value obtained by the above fitting, the equivalent thermal resistance between two adjacent working nodes and the equivalent thermal capacity of each working node can also be fitted, and a corresponding database can be constructed so that the corresponding parameters can be extracted from the database when the temperature data of a certain working node is subsequently calculated. This will not be described in detail.

[0043] Therefore, after having the thermal power value, equivalent heat capacity, and equivalent thermal resistance between the working node and the adjacent nodes, the thermal balance equation between the working node and the adjacent working nodes can be constructed accordingly, as shown in the following formula:

[0044]

[0045] in, represents the temperature of the nth working node at the i-th moment, Δt represents the time interval between the i-th moment and the i+1-th moment, It represents the temperature of the jth working node adjacent to the nth working node at the i-th moment, R j,n represents the equivalent thermal resistance between the nth working node and the jth adjacent working node, P n Represents the thermal power value of the nth working node, C n It indicates the equivalent heat capacity of the nth working node. It should be noted that the order number of the working node can be customized and is only used as the identification name corresponding to the working node. It will not affect the temperature data of other working nodes calculated, and there are no excessive restrictions on this.

[0046] Based on the formula of the heat balance equation, it can be seen that since heat will be transferred between different working nodes, the left side of the formula corresponds to the quotient of the temperature difference between the working node and the adjacent working node at the current moment for the temperature data to be calculated and the equivalent thermal resistance between the two working nodes, that is, the second temperature change, and the heat transfer between the working node and the adjacent working node and the thermal power value of the current working condition of the working node for which the temperature data needs to be calculated are represented by summing up all the second temperature changes, while the right side of the formula corresponds to the product of the temperature rise rate between the current moment and the previous moment of the working node for which the temperature data needs to be calculated and the corresponding equivalent heat capacity, to represent the temperature change before and after the working node, that is, the first temperature change. In addition, based on the conservation of heat, the first temperature change, the second temperature change, and the thermal power value of the current working condition of the working node are established to establish the equation of energy conservation, and finally form a heat balance equation as shown in the above formula.

[0047] In addition, based on the above heat balance equation, if you need to calculate the temperature data of a working node at the current moment, you also need its temperature data at the previous moment for calculation. To this end, the temperature data at any moment can be calculated in chronological order based on the initial temperature of each working node. How to obtain the initial temperature of the working node can be referred to as follows:

[0048] When the motor is not working, that is, under zero speed condition, Figure 4 As shown, the motor controller continuously sends multiple (for example, ≥3) short-term 12V DC pulse voltages with a duration of about 2ms, and the current sensor of the motor controller collects the current flowing through the motor winding, and then calculates the resistance value of the motor winding at this time based on the voltage and current values. The average of three times can be taken as the final resistance value. It should be noted here that if multiple short-term DC pulse voltages are set, the resistance values ​​calculated by the first and last short-term DC pulse voltages can be eliminated, and the average of the remaining resistance values ​​can be calculated as the final resistance value.

[0049] Finally, the initial temperature of the working node of the motor winding can be calculated based on the resistance value of the motor winding at this time and the actual current flowing through it. It can be understood here that Figure 4 The short-duration DC pulse voltage shown is only a preferred embodiment for reference only and is not intended to limit the protection scope of the present application.

[0050] At the same time, the initial temperature of the working node of the motor controller can be collected through the temperature sensor provided by the motor controller, and the maximum value can be selected from the initial temperature of the motor controller node and the initial temperature of the motor winding node to be equivalent to the initial temperature of each node, and the values ​​are assigned accordingly.

[0051] In summary, after obtaining the initial temperature of the working node, the temperature data at any time can be calculated accordingly according to the heat balance equation.

[0052] In a specific embodiment, Figure 3 The oil-cooled motor equivalent node network shown is taken as an example, and the initial time corresponding to the initial temperature is set to i=0.

[0053] At this time, according to Figure 2 It can be seen that the nodes adjacent to node 1 include node 2, node 3, and node 4. Therefore, the heat balance equation of node 1 is as follows:

[0054]

[0055] And the initial temperatures of nodes 2, 3, and 4 are known, so the temperature data of node 1 at the next moment after the initial moment, i.e., at moment i=1, can be calculated accordingly.

[0056] Similarly, the heat balance equation of node 2 is as follows:

[0057]

[0058] The temperature data T2 of node 2 when i=1 can be calculated accordingly 1 .

[0059] By analogy, the temperature data of each working node where i=1 can be calculated based on the initial temperature of the working node and the corresponding heat balance equation.

[0060] Similarly, when the temperature data of each working node at time i=1 is known, the temperature data of each working node at time i=2 can be calculated accordingly, thereby calculating the temperature data of each working node at different times in chronological order until the temperature data at the current time is obtained.

[0061] It should be noted that after calculating the temperature data of a certain working node at time i=1, and Re-iterate and calculate the thermal power value P of the working node n .

[0062] Furthermore, in order to verify whether the calculated initial temperature is reliable, a working node with a temperature sensor is selected, such as a working node of a motor controller, and after the initial temperature is calculated, the calculated initial temperature can be verified according to the actual temperature sampling value. If the calculated initial temperature is greater than the actual temperature sampling value, the verification is considered successful, and the temperature data at the next moment is calculated based on the calculated initial temperature; if the calculated initial temperature is less than the actual temperature sampling value, the verification is considered to have failed, and the initial temperature of the working node may be abnormal, and the actual temperature sampling value is assigned to the initial temperature of each working node, and the temperature data at the next moment is calculated based on the temperature data. In a specific embodiment, the junction temperature of the MOS tube or IGBT tube in the motor controller can be used.

[0063] Step S200: Based on the temperature data of one or more working nodes at the next moment, a corresponding over-temperature protection strategy is adopted to control the operation of the motor.

[0064] After calculating the temperature data of all working nodes, the output performance of the motor can be adjusted according to the temperature data of one working node or the temperature data of multiple working nodes, so that the oil-cooled bridge can work in the best state. Specifically, the corresponding temperature change is calculated according to the temperature data of the working node at the current moment and the temperature data at the next moment, and the output performance of the motor is adjusted according to the temperature change.

[0065] Preferably, Figure 3 Taking the oil-cooled motor equivalent node network shown in the figure as an example, the temperature change of node 6 can be used as the motor rating increase or decrease standard. Figure 5 As shown, corresponding to different temperature change ranges, the output performance of the motor can be increased or decreased according to a preset functional relationship, such as a linear proportional relationship or a nonlinear proportional relationship, such as controlling the maximum output power of the motor, and there are no excessive restrictions on this.

[0066] It should be noted that, in practical applications, there are no excessive restrictions on which temperature change amount of one or more working nodes is used to adjust the output performance of the motor. The above embodiments are for reference only and are not used to limit the scope of protection of this application. Those skilled in the art, without departing from the spirit of the present invention, the modifications and improvements made to the embodiments of the present invention still fall within the scope of the invention application of the present invention.

[0067] In addition, in the present embodiment, the calculated temperature data is also diagnosed to determine whether the data converges reliably. Specifically, in practical applications, the temperature data of any two adjacent moments of a certain working node can be selected, and the temperature data can be diagnosed whether the convergence is reliable based on the temperature change corresponding to the temperature data of the two adjacent moments and the pre-stored standard value. In a specific embodiment, node 6 can be selected, that is, the temperature data currently calculated by the motor winding is diagnosed. First, the motor controller determines whether the oil-cooled bridge is currently operating in the high-torque load condition interval, for example, it is identified whether the high torque is greater than or equal to the product of the motor peak torque and the fac coefficient (for example, fac takes 0.6). If this condition is met, it can be considered that the oil-cooled bridge is currently operating in the high-torque load condition interval, and the corresponding temperature rise rate can be calculated based on the temperature data of the working node of the motor winding in the middle 2 / 3 of the time within the high-torque load condition interval. It can be understood here that the temperature data used to calculate the temperature rise rate is calculated based on the thermal balance equation of the motor winding, so that the temperature data calculated using the thermal balance equation can be diagnosed. Finally, the calculated temperature rise rate is compared with the standard value of the temperature rise rate pre-stored in the database to diagnose whether the calculated temperature data is convergent and reliable, and an alarm response can be given for abnormal temperature data without restriction. Of course, other working nodes or multiple working nodes can also be selected for diagnosis, and the adjustment of the output performance of the oil-cooled motor can be stopped when the temperature data error is large, thereby improving the reliability of motor control management.

[0068] It should be noted that the step division of the above methods is only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they contain the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0069] Example 2

[0070] See also Figure 6 As shown, the embodiment of the present application also provides an electric drive system control system based on temperature calculation, including:

[0071] The temperature calculation module 10 is used to calculate the temperature data of each working node at the next moment according to the heat balance equation of the working node and the temperature data of each working node at the current moment; wherein the temperature data of each working node at the current moment is calculated based on the initial temperature of the working node and its heat balance equation;

[0072] The over-temperature protection module 20 is used to control the operation of the motor by adopting a corresponding temperature protection strategy based on the real-time temperature data of one or more working nodes.

[0073] It should be noted that the electric drive system control system based on temperature calculation provided in the above embodiment and the electric drive system control method based on temperature calculation provided in the above embodiment 1 belong to the same concept, wherein the specific manner in which each module and unit performs the operation has been described in detail in the method embodiment, and will not be repeated here. In practical applications, the electric drive system control method based on temperature calculation provided in the above embodiment 1 can allocate the above functions to different functional modules as needed, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0074] Example 3

[0075] See also Figure 7 As shown, an embodiment of the present application further provides an electronic device, comprising a memory 2, a processor 1, and a program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the program.

[0076] Among them, the memory includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (for example: SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. The memory can be an internal storage unit of an electronic device in some embodiments, such as a mobile hard disk of the electronic device. The memory can also be an external storage device of an electronic device in other embodiments, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Further, the memory can also include both an internal storage unit of the electronic device and an external storage device. The memory can be used not only to store application software and various types of data installed in the electronic device, but also to temporarily store data that has been output or is to be output.

[0077] In some embodiments, the processor may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and a combination of various control chips. The processor is the control core (Control Unit) of the electronic device, and uses various interfaces and lines to connect the various components of the entire electronic device, and executes various functions of the electronic device and processes data by running or executing programs or modules stored in the memory, and calling data stored in the memory.

[0078] The processor executes the operating system of the electronic device and various installed application programs. The processor executes the application programs to implement the steps in the above method embodiment.

[0079] Exemplarily, the program may be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of program instruction segments capable of completing specific functions, which are used to describe the execution process of the program in the vehicle terminal.

[0080] The above-mentioned integrated unit implemented in the form of a software function module can be stored in a computer-readable storage medium. The above-mentioned software function module is stored in a storage medium, and includes a number of instructions for enabling a computer device (which can be a personal computer, a computer device, or a network device, etc.) or a processor to perform part of the functions of the electric drive system control method based on temperature calculation in various embodiments of the present invention.

[0081] In summary, the present invention provides a method for detecting the temperature of an oil-cooled bridge, which can reduce the layout cost of the temperature sensor, thereby reducing the process complexity of installing the temperature sensor on the oil-cooled bridge. The operating temperature of key electronic or mechanical components such as motor windings and magnets can be obtained in real time during vehicle operation, so as to control the performance output of the motor accordingly and avoid temperature runaway, thereby improving the reliability of the oil-cooled bridge.

[0082] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for controlling an electric drive system based on temperature calculation, characterized in that: The electric drive system is composed of a plurality of electronic components and / or mechanical components as working nodes, wherein any working node can transfer heat with at least one other working node adjacent thereto; the method comprises: Calculate the temperature data of each working node at the next moment according to the heat balance equation of the working node and the temperature data of each working node at the current moment; wherein the temperature data of each working node at the current moment is calculated based on the initial temperature of the working node and its heat balance equation; Based on the real-time temperature data of one or more working nodes, a corresponding temperature protection strategy is adopted to control the operation of the motor in the electric drive system.

2. The electric drive system control method based on temperature calculation according to claim 1, characterized in that: The electric drive system at least includes: a motor, a motor controller, a reducer, and a cooling module; wherein the motor controller is provided with a temperature sensor for detecting temperature changes, and a current sensor for detecting current changes; The electronic components and / or mechanical components serving as working nodes include: motor windings, motor magnets, motor coolant, motor controller, motor controller coolant, reducer, heat exchanger, and radiator.

3. The electric drive system control method based on temperature calculation according to claim 2, characterized in that: The steps of obtaining the initial temperature of the working node include: After the electric drive system is powered on, the initial temperature of the motor winding is calculated according to the resistance value of the motor winding; Acquiring an initial temperature of the motor controller through a temperature sensor of the motor controller; A maximum value is selected from the initial temperature of the motor winding and the initial temperature of the motor controller as the initial temperature of each node.

4. The electric drive system control method based on temperature calculation according to claim 3, characterized in that: The step of obtaining the resistance value of the motor winding comprises: Sending multiple short-time DC pulse voltages through the motor controller, and collecting the line current corresponding to the motor through the current sensor of the motor controller; A plurality of resistance values ​​of the motor winding are calculated based on the short-time DC pulse voltage and the line current, and after removing the resistance values ​​calculated based on the first and last short-time DC pulse voltages, an average of the remaining plurality of resistance values ​​is taken as the final resistance value of the motor winding.

5. The electric drive system control method based on temperature calculation according to claim 1, characterized in that: Before obtaining the heat balance equation, it also includes: The thermal power values ​​of each working node under different working conditions are fitted by pre-set test data, and the corresponding database is constructed based on it; The equivalent thermal resistance between adjacent working nodes and the equivalent thermal capacity of each working node are obtained by fitting the preset test data, and the corresponding database is constructed based on them.

6. The electric drive system control method based on temperature calculation according to claim 1, characterized in that: The heat balance equation is obtained as follows: For each working node, Calculate the product of the temperature rise rate between the current moment and the previous moment of the working node and the equivalent heat capacity corresponding to the working node as the first temperature change; Calculating a quotient of a temperature difference between the working node and an adjacent working node at a current moment and an equivalent thermal resistance between the working node and an adjacent working node as a second temperature variation; An equation for energy conservation is established based on the first temperature change, the second temperature change, and the thermal power value corresponding to the current operating condition of the working node to form the thermal balance equation.

7. The electric drive system control method based on temperature calculation according to claim 1, characterized in that: The steps of obtaining the temperature data of the working node at the current moment include: The time corresponding to the initial temperature of the working node is taken as the initial moment, and the temperature data of the working node at the next moment after the initial moment is calculated according to the heat balance equation of the working node and the initial temperature of the adjacent working node; Based on the change in the working condition of the working node, the temperature data of the working node at the current moment is calculated in chronological order.

8. The electric drive system control method based on temperature calculation according to claim 1, characterized in that: Based on the real-time temperature data of one or more working nodes, the steps of taking corresponding temperature protection strategies to control the operation of the motor include: According to the temperature data of the working node at the current moment, the output performance of the motor in the electric drive system is adjusted.

9. The electric drive system control method based on temperature calculation according to claim 2, characterized in that: Also includes: Diagnose whether the temperature data calculated by each working node is convergent and reliable.

10. The electric drive system control method based on temperature calculation according to claim 9, characterized in that: The steps for diagnosing whether the temperature data of the working node is convergent and reliable include: Identify by the motor controller whether the electric drive system is currently operating in a high torque load condition range: If so, the temperature rise rate of a specific working node is calculated based on the temperature data of each working node within the large torque load condition range, and compared with the standard value of the temperature rise rate under the same condition in the preset database to identify whether the temperature data currently calculated at the working node is convergent and reliable.

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