Electronic oil pump control method and system of vehicle oil cooling electric drive system

Abstract

The invention relates to an electronic oil pump control method and system of a vehicle oil cooling electric drive system. The electronic oil pump control method of the vehicle oil cooling and electric driving system comprises the following steps that at least two operation parameters of the vehicle oil cooling and electric driving system are obtained, and the operation parameters comprise a temperature parameter and a parameter related to a load; comprehensively determining the required flow of the electronic oil pump based on the at least two operation parameters; inquiring pre-stored flow and rotating speed MAP data according to the required flow to obtain a corresponding target rotating speed of the electronic oil pump; based on the target rotating speed, the control current of the electronic oil pump is adjusted to control the actual rotating speed of the electronic oil pump, and then the required flow is provided; the electronic oil pump control method of the vehicle oil-cooling electric drive system can solve the problem that the electronic oil pump control strategy of a heavy truck electric drive system is not fine, and is high in efficiency.

Description

Technical Field

[0001] This invention belongs to the field of oil pump control technology, specifically relating to an electronic oil pump control method and system for vehicle oil-cooled electric drive systems. Background Technology

[0002] The oil-cooled electric drive system is a core power component of new energy commercial vehicles, and its reliability directly affects the performance and lifespan of the entire vehicle. This system generates a significant amount of heat during operation, especially under high load and high speed conditions, where the heat generation of the drive motor and transmission system becomes particularly prominent. Therefore, an efficient cooling and lubrication system is required to ensure that it operates within a safe temperature range.

[0003] Currently, the technical problem in this field is that the flow supply of traditional cooling and lubrication systems does not match the real-time demands of electric drive systems, leading to challenges to system reliability. Specifically, most existing technologies use mechanically driven oil pumps, whose pumping volume is only proportional to the engine or motor speed, and cannot be intelligently adjusted according to the actual thermal load of the electric drive system. This results in a double drawback: under low-speed, high-torque conditions, the system generates a lot of heat, but the oil pump speed is low, resulting in insufficient cooling and lubrication flow, which can easily cause overheating of the motor coils, bearing burnout, and gear wear; while under high-speed, low-torque conditions, the system requires a small flow, but the oil pump speed is high, providing excessive and unnecessary flow, which not only wastes energy and reduces the overall system efficiency, but also exacerbates unnecessary energy loss due to the unnecessary increase in pumping power.

[0004] While some solutions attempt to replace mechanical pumps with electronic oil pumps, their control strategies are often relatively simple, typically relying on a single parameter (such as coolant temperature) for switching or linear adjustment. This fails to comprehensively consider the real-time, dynamic heat load demands represented by multiple dimensions such as motor coil temperature, torque, and speed. Consequently, control precision and responsiveness are insufficient, and accurate matching of flow rate to demand remains impossible. Therefore, developing an electronic oil pump control strategy capable of precise on-demand flow supply based on multi-parameter collaborative decision-making is crucial for improving the reliability, efficiency, and lifespan of heavy-duty truck oil-cooled electric drive systems. Summary of the Invention

[0005] The purpose of this invention is to provide an electronic oil pump control method for a vehicle oil-cooled electric drive system that is simple in structure and reasonably designed in order to solve the above-mentioned problems.

[0006] The present invention achieves the above objectives through the following technical solutions: The first aspect of this invention provides an electronic oil pump control method for a vehicle oil-cooled electric drive system, comprising the following steps: Obtain at least two operating parameters of the vehicle's oil-cooled electric drive system, including temperature parameters and load-related parameters; Based on the at least two operating parameters, the required flow rate of the electronic oil pump is determined comprehensively. Based on the required flow rate, query the pre-stored flow rate and speed MAP data to obtain the corresponding target speed of the electronic oil pump; Based on the target rotational speed, the control current of the electronic oil pump is adjusted to control the actual rotational speed of the electronic oil pump, thereby providing the required flow rate.

[0007] As a further optimization of the present invention, the temperature parameters include motor coil temperature and / or motor lubricating oil temperature; the load-related parameters include one or more of motor torque, motor speed and motor power.

[0008] As a further optimization of the present invention, the required flow rate of the electronic oil pump is determined comprehensively based on the at least two operating parameters, specifically as follows: The at least two operating parameters are compared with preset thresholds respectively; When any operating parameter exceeds its corresponding threshold, a target speed is determined based on that parameter, and the maximum value among all determined target speeds is taken as the final target speed of the electronic oil pump.

[0009] As a further optimization of the present invention, the step of adjusting the control current of the electronic oil pump adopts a closed-loop control method, including: Real-time acquisition of the actual rotational speed of the electronic oil pump; Calculate the difference between the actual rotational speed and the target rotational speed; When the absolute value of the difference is greater than the first set tolerance, the control current is adjusted by step increase or decrease according to the sign of the difference with a preset step size.

[0010] As a further optimization of the present invention, a flow calibration step is also included: Real-time acquisition of the actual oil temperature of the electric drive system; Calculate the difference between the actual oil temperature and a preset base oil temperature; When the absolute value of the temperature difference is greater than the second set tolerance, the control current is adjusted according to the sign of the temperature difference to correct the deviation of the oil pump output flow caused by the change in oil temperature.

[0011] As a further optimization of the present invention, the specific method for compensating and adjusting the control current is as follows: querying a pre-stored three-dimensional MAP data table of speed, current, and flow rate that takes into account the influence of oil temperature.

[0012] As a further optimization of the present invention, the specific method for compensating and adjusting the control current is as follows: based on the temperature difference value, the current control current value determined by the speed closed-loop control is adjusted by additional step increment or step decrement according to a preset rule.

[0013] A second aspect of the present invention provides an electronic oil pump control system for a vehicle oil-cooled electric drive system, the system comprising: The sensor module is used to collect the at least two operating parameters; The controller is electrically connected to the sensor module and the electronic oil pump, and stores the flow-speed MAP data internally. The controller is configured to: Receive the operating parameters; Based on the at least two operating parameters, the required flow rate of the electronic oil pump is determined comprehensively. Query the flow-speed MAP data to obtain the corresponding target speed of the electronic oil pump; Based on the target rotational speed, a control signal is output to adjust the control current of the electronic oil pump.

[0014] As a further optimization of the present invention, the controller is also configured to perform speed closed-loop control: real-time acquisition of the actual speed of the electronic oil pump; Calculate the difference between the actual rotational speed and the target rotational speed; When the absolute value of the difference is greater than the first set tolerance, the control current is adjusted so that the actual rotational speed approaches the target rotational speed.

[0015] As a further optimization of the present invention, the controller is also configured to perform flow calibration control: Real-time acquisition of the actual oil temperature of the electric drive system; Calculate the difference between the actual oil temperature and a preset base oil temperature; When the absolute value of the temperature difference is greater than the second set tolerance, the control current is adjusted to compensate for the deviation in oil pump output flow caused by oil temperature changes.

[0016] The beneficial effects of this invention are as follows: By comprehensively collecting multiple operating parameters directly related to thermal load, such as motor coil temperature, oil temperature, torque, speed, and power, and making coordinated decisions, this invention can accurately identify the cooling and lubrication requirements of the system under different operating conditions in real time. Through querying MAP data and closed-loop control, the speed and flow rate of the electronic oil pump are precisely adjusted, completely solving the problems of insufficient flow rate leading to motor overheating, bearing erosion, and gear wear caused by insufficient flow rate under low-speed, high-torque conditions, and the inefficiency caused by excessive flow rate under high-speed, low-torque conditions, thus greatly improving the reliability and durability of the entire electric drive system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a flowchart of the electronic oil pump speed control logic of the present invention; Figure 3 This is a flowchart of the electronic oil pump flow control logic based on oil temperature according to the present invention. Detailed Implementation

[0018] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0019] Example 1

[0020] refer to Figure 1 , Figure 2 and Figure 3 As shown in the diagram, this embodiment provides an electronic oil pump control method for a vehicle oil-cooled electric drive system. The core of the control method provided by this embodiment lies in achieving on-demand adaptive control of the electronic oil pump flow rate through multi-parameter collaborative decision-making and precise table lookup based on MAP data.

[0021] See Figure 1 The schematic diagram of the control system structure shown in this embodiment mainly includes: Sensor group: used to collect operating parameters of the vehicle's oil-cooled electric drive system, including at least a motor coil temperature sensor, a motor oil temperature sensor, a torque sensor (or a torque signal calculated by the motor controller), and a motor speed sensor.

[0022] System controller (such as VCU or dedicated motor controller): It has pre-stored basic flow-speed MAP data of the electronic oil pump. This controller receives signals from the sensor array and executes the control method of this invention.

[0023] Electronic oil pump: Receives control current signal from system controller and feeds back its actual speed signal.

[0024] The control method of this embodiment specifically includes the following steps: S101. Obtain at least two runtime parameters: The system controller collects multiple operating parameters of the vehicle's oil-cooled electric drive system in real time. In this embodiment, the operating parameters include: Temperature parameters: Motor coil temperature (T) coil ), motor lubricating oil temperature (T) oil ); Load-related parameters: Motor torque (M) torque ), motor speed (RPM) motor ); S102. Determine the required flow rate of the electronic oil pump based on at least two operating parameters: This step is a specific implementation of "comprehensive determination" of demand flow. The system controller compares the collected operating parameters with preset safety thresholds. Preset motor coil temperature threshold: T coilmax (e.g., 180℃); Preset motor oil temperature threshold: T oilmax (e.g., 100℃); Preset motor torque threshold: M torquemax (e.g., 2000 N·m); Preset motor speed threshold: RPM motormax (e.g., 3000 rpm); The logic of the integrated decision-making process is as follows: when any operating parameter exceeds its corresponding threshold, the system queries its individual corresponding "parameter-demand flow rate" mapping relationship (which can be pre-calibrated through bench testing) to calculate a temporary demand flow rate value. The system controller then selects the maximum value from all calculated temporary demand flow rate values ​​as the final electronic oil pump demand flow rate (Q). demand ).

[0025] This "maximum value" strategy is a reliable and effective comprehensive decision-making method that ensures that the cooling and lubrication flow rate can meet the most pressing needs under any harsh operating conditions.

[0026] S103. Based on the required flow rate, query the pre-stored flow rate-speed MAP data to obtain the target speed: The system controller internally stores basic flow-speed MAP data for the electronic oil pump. This MAP data describes the flow rate at a specific oil temperature (e.g., base oil temperature T). base The relationship between the speed of an electronic oil pump and its output flow rate under the following conditions; The controller uses the final demand flow Q determined in step S102. demand By performing lookup and interpolation on the MAP data table, the target speed (RPM) of the electric oil pump required to achieve this flow rate can be obtained. target ); S104. Based on the target speed, adjust the control current to control the actual speed: The system controller outputs a control signal (usually a PWM signal) to regulate the control current (I) of the electronic oil pump. control The aim is to increase the actual speed (RPM) of the electronic oil pump.actual approaching the target rotational speed (RPM target ); This embodiment adopts a closed-loop speed regulation strategy, which specifically includes: Obtaining the actual rotational speed RPM feedback by the electronic oil pump in real time actual .

[0027] Calculating the absolute value of the deviation between the actual rotational speed and the target rotational speed |ΔRPM| = |RPM actual - RPM target |; Comparing |ΔRPM| with a preset rotational speed tolerance M (such as 50 RPM); If |ΔRPM| < M, it is considered that the rotational speed control has met the accuracy requirements, and the current control current remains unchanged; If |ΔRPM| ≥ M, then according to a preset current step value N (such as 0.05 A), the control current is adjusted step by step up or down (if RPM actual < RPM target , the current is increased step by step; otherwise, the current is decreased step by step), until |ΔRPM| < M; Through the above steps, the present invention realizes the precise on-demand control of the electronic oil pump flow based on multi-parameter feedback, effectively solves the problems of insufficient low-speed cooling, excessive high-speed flow, inaccurate control, etc. described in the background art, and significantly improves the system reliability and efficiency.

[0028] It should be further noted that: The temperature parameter includes the motor coil temperature (T coil ) and / or the motor lubricating oil temperature (T oil ). Those skilled in the art can understand that the meaning of "and / or" includes only using the motor coil temperature, only using the motor lubricating oil temperature, or using both at the same time.

[0029] Among them, for the acquisition of the motor coil temperature (T coil ): In an oil-cooled motor, the motor coil (stator winding) is the direct key heat source. Its temperature is usually directly measured by a temperature sensor (such as a PT100 platinum resistance or an NTC thermistor) embedded in the motor stator slot or on the end winding. The sensor signal is transmitted to the analog / digital input port of the system controller (such as the motor controller MCU or the vehicle controller VCU) through a wire harness, and the controller samples and performs A / D conversion to obtain the real-time motor coil temperature value. This parameter directly reflects the working temperature of the hottest point inside the motor and is the most direct and crucial parameter to prevent the motor insulation from overheating and damage.

[0030] Among them, for the acquisition of the motor lubricating oil temperature (T oilThe acquisition of motor lubricating oil temperature reflects the overall thermal state of the oil in the entire cooling and lubrication circuit. It is typically measured using a temperature sensor installed in the motor's lubrication channels or oil pan. The signal is then transmitted to the system controller for processing. Oil temperature is crucial because it affects not only the motor's heat dissipation efficiency but also the viscosity of the lubricating oil, which in turn affects the output characteristics (flow rate and load) of the electronic oil pump. For example, during low-temperature starts, the oil is viscous, and the pump's output flow rate at the same speed will be lower than the calibrated value in the MAP (usually calibrated at standard oil temperature), while the load is greater; the opposite is true at high temperatures. Therefore, oil temperature is an indispensable parameter for accurate flow rate compensation control.

[0031] Among them, the acquisition of load-related parameters includes motor torque (M). torque ), motor speed (RPM) motor ) and motor power (P) motor One or more of the following parameters. These parameters collectively characterize the real-time load and operating intensity of the electric drive system and are closely related to the system's heat generation.

[0032] Among them, for motor torque (M) torque Obtaining torque: Motor torque is a key parameter that directly reflects the load magnitude. There are generally two methods to obtain it: First, direct measurement using a torque sensor, i.e., installing a torque sensor on the drive shaft to directly acquire the real-time torque signal; second, calculation by the motor controller, which is the more common and cost-effective method. In permanent magnet synchronous motor (PMSM) or induction motor (IM) drive systems, the motor controller (MCU) calculates the motor's output torque in real time based on its output q-axis current (Iq) and the motor's electromagnetic parameters (such as the torque constant Kt) (the calculation formula is: Mtorque ≈ Kt). Iq). This calculated value is sent via the Controller Area Network (CAN bus) to the system controller (VCU or standalone controller) that executes this control strategy.

[0033] Among them, for motor speed (RPM) motor Acquisition of motor speed: Motor speed is one of the most fundamental operating parameters of a motor. The motor controller (MCU) can obtain the real-time position and speed of the motor rotor with extremely high precision by analyzing the signals from the motor's built-in resolver or encoder. This speed information is also shared with the system controller via the CAN bus.

[0034] Among them, for motor power (P) motor The acquisition of motor power (P): Motor power is a comprehensive reflection of torque and speed. motor ≈M torque RPMmotor / 9550). Its acquisition method is usually not direct measurement, but rather the system controller obtains it based on the received motor torque (M). torque ) and motor speed (RPM) motor The signal is calculated in real time. High power usually means high heat generation, and is therefore a strongly correlated parameter that triggers high-level cooling requirements.

[0035] In a preferred embodiment of the present invention, the system controller simultaneously acquires the following parameters as input for comprehensive decision-making: Temperature parameters: Motor coil temperature (T) coil ), motor lubricating oil temperature (T) oil ); Load-related parameters: Motor torque (M) torque ), motor speed (RPM) motor ); The controller sets independent thresholds for each of the four parameters. When any parameter exceeds its threshold, the controller queries a pre-calibrated data table to calculate a temporary demand flow based on the severity of the exceedance (e.g., the percentage of exceedance). The final system demand flow is the maximum value among all temporary demand flows.

[0036] For example, under heavy-load uphill conditions, the motor torque (M) torque ) and motor coil temperature (T) coil The temperature may rise rapidly and exceed the threshold simultaneously. The controller will calculate two demand flow rates based on the torque and coil temperature respectively, and select the larger one to control the electronic oil pump, thereby ensuring that the cooling and lubrication capacity is sufficient and not excessive under any single or combined operating conditions.

[0037] The specific steps for comprehensively determining the required flow rate (target speed) are as follows: S201. Preset independent thresholds for each operating parameter: The system controller has multiple pre-stored independent trigger thresholds for its operating parameters. These thresholds were calibrated through prior bench testing and vehicle road testing to ensure system reliability under different operating conditions. For example, the following can be set: Motor coil temperature threshold: T coilth = 180°C; Motor lubricating oil temperature threshold: T oilth = 100°C; Motor torque threshold: M torqueth = 2000 N·m; Motor speed threshold: RPM motorth = 3000 rpm; Motor power threshold: P motorth= 300 kW; S202, Real-time Comparison and Independent Decision-Making: The system controller continuously compares the collected real-time operating parameters with their respective thresholds in step S201; When any running parameter exceeds its own specific threshold, an independent decision branch is triggered; For each parameter exceeding the limit, the controller will look up a pre-calibrated "parameter-demand speed" mapping table (or curve) based on the specific value of the parameter exceeding the limit, and calculate a temporary target speed (RPM) corresponding to the current state of that parameter. tempi , where i represents the parameter that triggers the operation.

[0038] The aforementioned "parameter-required speed" mapping relationship can be calibrated by those skilled in the art through routine experiments: For example, the motor torque parameter can be calibrated as follows: When M torque >M torqueth At that time, RPM temptorque = f(M torque ); The function f can be a simple linear relationship: RPM temptorque = K (M torque - M torqueth +RPM base (K is the proportionality coefficient, RPM) base (Base speed).

[0039] Alternatively, it can be a more complex two-dimensional lookup table (MAP), with the horizontal axis representing the motor torque value and the vertical axis representing the corresponding required speed value. This MAP ensures that the higher the torque, the higher the required speed, in order to meet greater cooling and lubrication demands.

[0040] Similarly, establish independent mapping tables f for parameters such as temperature, speed, and power. temp (M torque ), f coil (T coil ), f RPM (RPM motor ), f power (P motor ); S203. Take the maximum value as the final target rotational speed: During each control cycle, the system controller checks all temporary target speeds (RPM) calculated from the out-of-limit parameters. temp1, RPM temp2, ..., RPM tempn; Final target speed of the electric oil pump (RPM) target This was determined to be the maximum value among all these temporary demand target speeds. That is: RPM target = max(RPM temp1 RPM temp2 , ..., RPM tempn ); If no parameters exceed the limit, then RPM target Maintain a preset idle speed or the speed found in the default MAP to provide basic lubrication.

[0041] Application example: Under one working condition: Motor torque M torque = 2200 N·m (exceeding the threshold of 2000 N·m), after consulting the corresponding mapping table, the temporary required speed RPM is obtained. temptorque = 2500 rpm; Motor coil temperature T coil = 170°C (not exceeding the threshold of 180°C), no decision branch is triggered; Motor oil temperature T oil = 105°C (exceeding the 100°C threshold), after consulting the corresponding mapping table, the temporary required speed RPM is obtained. tempoil = 2800 rpm; The system controller will then set the final target speed as follows: RPM target = max(2500, 2800) = 2800 rpm.

[0042] This strategy ensures that the system's cooling and lubrication capabilities always meet the demands of the most demanding operating conditions. In the example above, although the torque is already high, the oil temperature exceeds the limit even more severely, indicating that the cooling system is facing greater pressure. Therefore, a higher oil pump speed is used to prioritize addressing the excessive oil temperature issue, thereby maximizing system reliability.

[0043] Furthermore, this embodiment specifies the step of "adjusting the control current of the electronic oil pump based on the target speed," and elaborates on the speed closed-loop control method employed. This method aims to eliminate speed deviations caused by factors such as changes in oil pump load, power supply voltage fluctuations, and changes in oil viscosity, ensuring that the actual speed of the electronic oil pump accurately tracks the target speed.

[0044] The closed-loop control method specifically includes the following steps: S301. Real-time acquisition of the actual speed of the electronic oil pump: Electric oil pumps typically incorporate a Hall effect sensor or encoder to detect the rotor position of the internal motor. The electric oil pump controller (or system controller) can accurately calculate the actual rotational speed (RP) of the electric oil pump motor in real time by reading the pulse signal frequency emitted by the sensor (for Hall sensors) or analyzing encoder data. Mactual ); S302. Calculate the difference between the actual rotational speed and the target rotational speed: In each control cycle (e.g., a cycle of 1ms or 5ms), the system controller performs the following calculation once: ΔRPM = RPM actual - RPM target And calculate its absolute value as |ΔRPM|.

[0045] Wherein, RPMtarget is the target rotational speed value determined by the aforementioned steps (such as querying MAP and multi-parameter decision-making); S303. Determine and execute step adjustment: The system controller compares the absolute value of the speed deviation, |ΔRPM|, with a preset first set tolerance (M). This tolerance M is an allowable steady-state error in speed control, the value of which can be calibrated experimentally according to the control accuracy requirements, for example, set to M = 50 RPM; Judgment condition 1: If |ΔRPM| <M This indicates that the actual speed of the electric oil pump has entered the acceptable range of the target speed, meeting the control accuracy requirements. At this time, the system controller maintains the current control current ( Icontrol If the output remains unchanged, it signifies the end of control or the entry into a steady-state holding phase. This avoids frequent actions by the control system and improves system stability. Condition 2: If |ΔRPM| ≥ M This indicates a significant deviation between the actual and target speeds, necessitating adjustment. The direction and magnitude of the adjustment are determined by the following rules: Direction determination: The adjustment direction is determined by the sign of the difference ΔRPM.

[0046] If ΔRPM < 0 (i.e. RPM) actual <RPM target If the actual speed is too low, it means that the control current needs to be increased (step increase).

[0047] If ΔRPM>0 (i.e. RPM) actualRPM target If the actual speed is too high, it means that the control current needs to be reduced (step reduction).

[0048] Amplitude control: The control current is changed in units of a preset fixed current step value (N). For example, the step size N is set to 0.05A.

[0049] When step increment is required, the new control current value is: I controlnew = Icontrol old + N; When step reduction is required, the new control current value is: I controlnew = Icontrol old - N; The controller will assign a new current value I controlnew The output is supplied to the electronic oil pump (current regulation is usually achieved by changing the PWM duty cycle). S304, Loop Feedback: The above steps S301 to S303 are executed cyclically in each control cycle, forming a closed-loop feedback control system (its flowchart can be found in [reference needed]). Figure 2 Through this continuous "measurement-comparison-correction" process, the actual speed of the electronic oil pump is dynamically adjusted and eventually stabilized within the target speed tolerance range (RPM). target Within ± M), thus precisely providing the required cooling lubricant flow rate.

[0050] Furthermore, a flow calibration step is introduced into the electronic oil pump control method. This step aims to address a key issue: the output flow rate of the electronic oil pump is not only related to the rotational speed but also significantly affected by the viscosity of the lubricating oil, which in turn depends primarily on the oil temperature. At low temperatures, the oil is viscous, resulting in a larger pumped load at the same rotational speed, and the actual flow rate may be lower than expected; at high temperatures, the oil is thinner, and the actual flow rate may be higher than expected. The aforementioned closed-loop speed control cannot completely overcome this deviation caused by changes in physical characteristics, hence the need for this calibration step.

[0051] The flow calibration step specifically includes the following steps: S401. Real-time acquisition of the actual oil temperature of the electric drive system: The actual oil temperature (T) of the motor lubrication system is collected in real time by an oil temperature sensor (such as a PT1000 platinum resistance thermometer or an NTC thermistor) installed in the motor lubrication oil passage or oil tank. oilactual The sensor signal is transmitted to the system controller. S402. Calculate the difference between the actual oil temperature and the preset base oil temperature: The system controller has a preset base oil temperature (T). baseThis temperature is typically the reference oil temperature used for calibrating the flow-speed MAP data of the electronic oil pump (e.g., T). base = 80°C). The system controller calculates the deviation between the actual oil temperature and the base oil temperature: ΔT = T oilactual - T base ; And calculate its absolute value as |ΔT|; S403. Determine and execute current compensation adjustment: The system controller compares the absolute value of the oil temperature difference, |ΔT|, with a preset second set tolerance (M1). This tolerance M1 defines the oil temperature dead zone range that does not require compensation adjustment, and its value can be determined experimentally (e.g., M1 = 5°C or 10°C). Condition 1: If |ΔT| ≤ M1 This indicates that the actual oil temperature is close to the baseline oil temperature at MAP calibration, and the impact of oil viscosity changes on flow rate is within acceptable limits. Therefore, the system controller does not initiate current compensation regulation, and the electronic oil pump is regulated solely by speed closed-loop control. This helps reduce frequent system operations. Judgment condition two: If ΔT>M1 (i.e., the actual oil temperature is significantly higher than the base oil temperature); At this point, the oil viscosity becomes thinner, and at the same rotational speed, the actual output flow rate of the electronic oil pump will be higher than the expected flow rate obtained based on the standard viscosity MAP. To correct this positive deviation, the system controller needs to perform negative compensation (step reduction) on the control current.

[0052] Example of compensation method: The controller adjusts the current control current in steps by a preset current compensation step size (N) (e.g., N = 0.02A). That is: I controlcompensated = I control - N.

[0053] Judgment condition 3: If ΔT < -M1 (i.e., the actual oil temperature is significantly lower than the base oil temperature) At this point, the oil viscosity increases, and at the same rotational speed, the actual output flow rate of the electronic oil pump will be lower than the expected flow rate obtained from the standard viscosity MAP, and the pump's operating load will increase. To correct this negative deviation and ensure starting capability, the system controller needs to perform positive compensation (step-increment) on the control current.

[0054] Example of compensation method: The controller adjusts the current control current in increments according to the preset current compensation step size (N). That is: I controlcompensated = I control + N.

[0055] S404, Integrated Application: The output of this flow calibration step is a compensated control current value (I0). controlcompensated This current value will be used as a new setpoint for the speed closed-loop controller or directly output to the electronic oil pump. This adds a feedforward compensation based on oil temperature to the speed closed-loop control, working together to ensure that the electronic oil pump can output an actual flow rate close to or the same as the target requirement at different oil temperatures. Furthermore, the step of "compensating and adjusting the control current" is specified. Those skilled in the art will understand that both of the following methods can be used independently to achieve oil temperature compensation, and the choice depends on the system's control accuracy requirements, calibration resources, and computing power.

[0056] Method 1: Query the 3D MAP data table: This is a precise compensation method based on feedforward table lookup.

[0057] S501, Pre-stored 3D MAP data table: During the system development phase, extensive bench tests were conducted at different oil temperatures (T). oil ), different control currents (I) control Under these conditions, measure the output speed (RPM) of the electronic oil pump. actual ) and actual flow (Q) actual This allows for the construction and storage of a three-dimensional MAP data table (or flow-current-oil temperature three-dimensional MAP) that establishes the precise control current value required to achieve a target flow rate (or target speed) at any oil temperature and operating point.

[0058] S502, Query and Interpolation: When performing the flow calibration step, the controller knows: The target flow rate (or which can be converted into a target speed in RPM) is determined by the superior control strategy. target ); Real-time collected actual oil temperature (T) oilactual ).

[0059] The controller uses (RPM) target , T oilactual Using the above three-dimensional MAP data table as input, perform two-dimensional lookup and interpolation operations (e.g., bilinear interpolation) to directly output an optimal control current value (I) after oil temperature compensation. compensated ).

[0060] S503, Output Control: The controller directly uses this calculated I compensatedThe output is sent to the electronic oil pump, eliminating the need for additional step adjustments. This method is essentially an open-loop feedforward compensation, the accuracy of which depends on the fineness of the MAP data, and it can very accurately counteract the effects of oil temperature changes.

[0061] Method 2: Step increment / decrement adjustment based on preset rules: This is a simplified compensation method based on feedback rules, which has low computational cost and is easy to implement.

[0062] S511. Set Compensation Rule: Preset a compensation rule that defines the functional relationship between the oil temperature difference (ΔT) and the current compensation amount (ΔI). This rule can be a simple linear relationship or a one-dimensional MAP table calibrated through experiments.

[0063] Example of a linear rule: ΔI = K ΔT (where K is the compensation coefficient, in A / °C); If ΔT>0 (oil temperature is too high), then ΔI is negative, and the current needs to be reduced. If ΔT < 0 (oil temperature is too low), then ΔI is a positive value and the current needs to be increased. Example of MAP representation: Construct a one-dimensional table with ΔT on the horizontal axis and the corresponding ΔI value on the vertical axis.

[0064] S512. Calculate the compensation current: During the flow calibration step, the controller calculates the oil temperature difference ΔT = T. oilactual - T base .

[0065] According to the preset rules in step S511, the required current compensation amount ΔI is calculated.

[0066] S513, Superimposed Output: The controller obtains the current reference control current value (I) from the speed closed-loop control loop. base This value is the current calculated to achieve the target rotational speed.

[0067] The compensation amount is added to the reference current to obtain the final control current output: I compensated = I base + ΔI; This method adds an additional compensation loop to the closed-loop speed control, and the amount of compensation is directly determined by the deviation between the measured oil temperature and the reference oil temperature.

[0068] Method 1 (3D MAP) offers the highest control accuracy, but requires extensive calibration work and places slightly higher demands on the controller's storage and computing capabilities.

[0069] Method 2 (rule adjustment) is simple to implement and requires little computation. It is an efficient and practical engineering optimization method that is sufficient to meet the accuracy requirements of most application scenarios.

[0070] Example 2

[0071] This embodiment describes in detail an electronic oil pump control system for a vehicle oil-cooled electric drive system, which is used to implement the aforementioned electronic oil pump control method.

[0072] The electronic oil pump control system mainly includes the following parts: Sensor module: Used to collect at least two operating parameters of the vehicle's oil-cooled electric drive system. The sensor module specifically includes: Temperature sensor: Used to collect temperature parameters. Including but not limited to: Motor coil temperature sensors (such as PT100 platinum resistance thermometers) are embedded in the motor stator windings to directly measure the coil temperature.

[0073] Oil temperature sensors (such as NTC thermistors) are installed in the motor lubrication circuit or oil pan to measure the temperature of the lubricating oil.

[0074] Load-related parameter sensors: used to collect parameters related to the system load. These parameters typically originate from the electric drive system itself and are shared via the Controller Area Network (CAN bus), including but not limited to: Torque signal: Calculated in real time by the motor controller (MCU) based on its output q-axis current and motor torque constant.

[0075] Speed ​​signal: Obtained by the motor controller (MCU) by analyzing the motor's rotary transformer or encoder signal.

[0076] Power signal: can be calculated in real time by the system controller based on the received torque and speed signals (P = M). n / 9550).

[0077] Controller: The controller is the core processing unit of the system, and can be a vehicle controller (VCU), a motor controller (MCU), or a separate dedicated controller.

[0078] The controller is electrically connected to the sensor module via hardwired lines or a CAN bus to receive the aforementioned operating parameters.

[0079] The controller is electrically connected to the electric oil pump via a control line (such as an output PWM signal) to output a control current signal to it.

[0080] The controller contains a storage unit (such as a Flash memory) that pre-stores the flow-speed MAP basic data, as well as the tolerance values ​​(M, M1), step size values ​​(N), and base oil temperature (T) which will be discussed later. base Calibration parameters such as ( ).

[0081] Electronic oil pump assembly: The electronic oil pump receives a control current signal from the controller and adjusts the speed of its internal motor accordingly.

[0082] The electronic oil pump has a built-in speed feedback device (such as a Hall effect sensor) to detect the actual speed of the pump in real time and feed the actual speed signal back to the controller.

[0083] The controller is configured to execute the following control logic: The controller is configured to perform the following steps in a loop: Receive operating parameters: Receive at least two operating parameters (such as motor coil temperature, motor oil temperature, and motor torque) from the sensor module through its input interface and CAN bus. Determine the required flow rate comprehensively: Based on the at least two operating parameters, comprehensively determine the required flow rate of the electronic oil pump. For example, adopt the "maximum value" strategy as described above: compare each parameter with an independent threshold, calculate a temporary required speed for each parameter exceeding the limit, and take the maximum value as the final demand; To obtain the target speed from the MAP: Using the required flow rate (or directly the required speed) as input, query the pre-stored flow-speed MAP data, and calculate the precise target speed (RPM) of the electronic oil pump through interpolation. target ); Output control signal: based on the target rotational speed (RPM) target The electronic oil pump is driven by the output of the corresponding control signal (adjusting the PWM duty cycle to equivalently adjust the control current) through its output interface (such as a PWM generator). The controller is further configured to initiate speed closed-loop control when executing the above main logic step 4: Real-time acquisition of actual speed: The actual speed (RPM) fed back by the electronic oil pump is read in real time through its input interface. actual ).

[0084] Calculate the difference: Calculate the absolute value of the deviation between the actual speed and the target speed |ΔRPM| = |RPM actual -RPM target |

[0085] Judgment and Adjustment: When |ΔRPM| is less than or equal to the first set tolerance (M, such as 50 RPM), the current control current output remains unchanged; When |ΔRPM| is greater than the first set tolerance (M), the control current is increased in steps according to the sign of the difference, using a preset current step size (N, such as 0.05A). actual <RPM target ) or step reduction (if RPM actual RPM target Adjust and repeat this process until |ΔRPM| is less than M.

[0086] The controller is further configured to perform flow calibration control in parallel while performing control: Real-time acquisition of actual oil temperature: The actual oil temperature (T) of the electric drive system is continuously acquired via an oil temperature sensor. oilactual ); Calculate the oil temperature difference: Calculate the difference between the actual oil temperature and the preset base oil temperature (T). base For example, 80°C, this value is the difference ΔT = T between the flow rate and the rated oil temperature of the speed MAP. oilactual - T base Find the absolute value |ΔT|; Judgment and Compensation Adjustment: When |ΔT| is less than or equal to the second set tolerance (M1, such as 10°C), compensation adjustment is not activated; When |ΔT| is greater than the second set tolerance (M1), the control current is adjusted to compensate for the flow deviation caused by oil temperature. If ΔT>M1 (oil temperature too high), then the current control current will be reduced in steps according to the preset rules (such as a compensation step size); If ΔT < -M1 (oil temperature too low), the current control current will be compensated by step increment according to the preset rules.

[0087] This compensation amount can be superimposed on the current value output by the speed closed-loop control, and together they serve as the final control current output.

[0088] This invention is not a simple single-loop control, but rather a multi-layered intelligent control architecture that includes a multi-parameter decision layer, a speed closed-loop control layer, and an oil temperature compensation layer. The speed closed-loop control ensures rapid and accurate tracking of the target speed command, overcoming interference from load fluctuations and voltage changes. The oil temperature-based flow compensation control further corrects flow deviations caused by changes in oil viscosity, ensuring that the final output flow value remains highly accurate under various ambient temperatures, exhibiting extremely strong control robustness. Thanks to its on-demand control strategy, the electronic oil pump operates at a speed that matches actual demand most of the time, avoiding unnecessary energy loss. Compared to pumps that always run at full speed or are simply controlled, this invention significantly reduces the power consumption of the electronic oil pump, thereby improving the energy efficiency of the entire electric drive system. For new energy heavy trucks, this translates to a longer driving range and has significant economic value.

[0089] The "maximum value" decision logic, step-by-step adjustment method, and two optional oil temperature compensation methods (3D MAP lookup or rule-based compensation) provided by this invention offer flexible options for engineering applications, adaptable to different cost and control accuracy requirements. The strategy has a clear principle, is easy to implement and expand on existing vehicle controller platforms, and has broad prospects for industrial application.

[0090] Example 3

[0091] Based on the above embodiments, in order to continuously ensure the reliability and accuracy of thermal management of the oil-cooled electric drive system under complex and ever-changing external environments and the possibility of internal sensor failure, the following solution is implemented: In this embodiment: Step 1: Multi-dimensional data collection and preprocessing: This step forms the data foundation of the control method, aiming to provide comprehensive and reliable input information for subsequent intelligent decision-making. The system controller receives and preprocesses data signals from three dimensions through its hardware interface and communication network: Collection of internal operating parameters: The internal operating parameters directly reflect the real-time operating status and thermal load of the vehicle's oil-cooled electric drive system. The data collection method is as follows: Motor coil temperature (T) coil Temperature is measured directly using a temperature sensor (such as a PT100 platinum resistance thermometer or an NTC thermistor) embedded in the motor stator windings. The analog voltage or resistance signal generated by this sensor is transmitted via a hardwired connection to the analog-to-digital converter (ADC) interface of the system controller. The controller samples and converts the signal to obtain a digitized temperature value. This parameter is a direct indicator of the temperature of the hottest spot inside the motor. Motor lubricating oil temperature (T) oil This parameter is measured by a temperature sensor installed in the motor's lubrication oil passage, oil pan, or cooling circuit. Its signal transmission and processing are similar to those of a coil temperature sensor, and it is connected to the system controller via an ADC interface. This parameter is used to evaluate the thermal state and viscosity characteristics of the lubricating oil. Motor torque (M) and motor speed (RPM) motorThese two parameters typically do not require additional physical sensors. In a preferred embodiment, the system controller obtains the information in real time from the motor controller (MCU) via a controller area network (CAN bus). The motor controller obtains the precise motor speed (RPM) by resolving the motor resolver or encoder signal. motor The motor torque (M) is calculated in real time based on its output q-axis current (Iq) and motor torque constant (Kt) (the calculation formula is: M ≈ Kt). Iq). These parameters are periodically sent to the bus in the form of CAN messages; Motor power (P) motor This parameter is typically determined by the system controller based on the received motor torque (M) and motor speed (RPM). motor ) signal, through formula (P motor = M RPM motor The load strength of the system is calculated in real time ( / 9550) and used to comprehensively characterize the load strength of the system.

[0092] Collection of external environmental parameters: The external environmental parameters are used to assess the impact of the vehicle's external climate and geographical conditions on its heat dissipation efficiency.

[0093] Ambient temperature (T) env The ambient temperature is measured by an ambient temperature sensor installed near the vehicle's front grille or in the engine compartment ventilation area to avoid interference from engine heat radiation. The signal is then connected to the system controller via an ADC interface. Atmospheric pressure (P) env It can be obtained in two alternative ways: Method 1 (Direct Measurement): Measurement is taken directly using an atmospheric pressure sensor installed on the vehicle body. This is the most accurate method. Method 2 (Indirect Calculation): Altitude information is obtained from other vehicle controllers (such as the engine ECU or network management system) via the CAN bus. The system controller calculates an approximate atmospheric pressure value (P) based on the correspondence between altitude and atmospheric pressure (using pre-stored empirical formulas or lookup tables). env This method can reuse existing vehicle signals, reducing costs.

[0094] System status parameter acquisition: The system status parameters are used to provide feedback on the operation of the electronic oil pump itself and are the basis for achieving closed-loop control.

[0095] Actual speed of electronic oil pump (RPM) actualThe electronic oil pump assembly integrates a speed feedback device, such as a Hall effect sensor. This sensor generates a pulse frequency signal (FG signal) as the oil pump motor rotor rotates. This signal is transmitted via hardwire to the digital input interface or dedicated frequency capture interface of the system controller, which can calculate the accurate actual speed by measuring the pulse frequency. Electronic oil pump control current (I) control The system controller generates a control signal through its pulse width modulation (PWM) output interface to drive the electric oil pump. The control current (I0) control The value of the current is proportional to the duty cycle of the PWM signal. The controller can obtain or calculate the current output control current value in real time by querying the correspondence between the PWM duty cycle and the output current, or by sampling the voltage on the current sampling resistor in the ADC drive circuit. Signal preprocessing: Before using the raw signals acquired above, the system controller can perform necessary software preprocessing to improve the reliability and stability of the data, for example: Software filtering: Algorithms such as first-order low-pass filtering (Infinite Impulse Response, IIR) or moving average filtering are used to smooth the acquired signal in order to eliminate high-frequency noise interference; Validity verification: Perform CRC verification on the data received via the CAN bus to ensure the integrity and correctness of the data frames; Through the above steps, the system controller obtains all the input information necessary to achieve environmental adaptation and fault-tolerant intelligent control, laying a solid data foundation for the execution of subsequent steps.

[0096] Step 2: Multi-level sensor fault diagnosis and reliability assessment: This step is crucial for ensuring the robustness of the control system. The system controller performs parallel checks on key sensors (such as the motor coil temperature T). coil and motor lubricating oil temperature T oil Taking [example] as an example, real-time fault diagnosis and reliability assessment are performed, and the output results provide a basis for subsequent fault-tolerance decisions. The diagnosis is conducted at two levels: Physical rationality diagnosis: The controller compares the raw sensor values ​​it acquires with a pre-stored physical range in its internal memory. This range is determined based on the theoretical limits of the device, the limits of the vehicle's operating environment, and engineering experience. For motor coil temperature (T) coil): Determine if the value exceeds reasonable limits. For example, if Tcoil > 250°C (far exceeding the common heat resistance rating of motor insulation materials, such as Class H 180°C) or Tcoil < -40°C (below the lowest ambient temperature at which the vehicle may operate), then immediately determine that the sensor has suffered a permanent failure (Flag). Tcoil = "fault"); For motor lubricating oil temperature (T) oil ): Determine whether its value exceeds the reasonable boundary, for example: if T oil >150°C (the oil may severely deteriorate or boil) or T oil If the temperature is below -40°C, the sensor is immediately considered to have suffered a permanent failure (Flag). Toil = "fault"); This diagnostic layer is used to capture obviously absurd data generated due to sensor short circuits, open circuits, or complete failure.

[0097] Relevance logic diagnosis: For data that passes the physical plausibility check, the controller further performs a logical relevance check based on the system's operating principles. This check is automatically activated after the system has been running for a period of time (e.g., 2 minutes after engine start). For motor coil temperature sensor (T) coil Diagnosis of ) A simplified temperature rise estimation model is established: the controller utilizes real-time collected motor torque (M) and motor speed (RPM) data. motor Calculate motor power (P) motor Based on thermodynamic principles, the temperature rise of the motor coil is related to the motor's heat output (primarily dependent on P). motor There is a certain relationship between them, while also considering basic heat dissipation. A simplified, diagnostic, first-order discrete estimation model can be expressed as: T coilestimated (k)=T coilestimated (k-1)+[α P motor (k)-β (T coilestimated (k-1)-T env (k))] ΔT; Where k is the current sampling time, ΔT is the sampling period, α is the heating coefficient related to motor efficiency, β is the heat dissipation coefficient, and T is the heat dissipation coefficient. env The ambient temperature is used. Coefficients α and β can be obtained through bench testing. Deviation Comparison and Judgment: The controller continuously calculates the measured value T. coil Compared with the model estimate T coilestimated The absolute value of the deviation |ΔTcoil | = |T coil - T coilestimated |; Fault determination: If |ΔT coil If a system continuously exceeds a set reasonable deviation threshold (e.g., 15°C) for a period of time (e.g., 30 seconds), and this deviation cannot be explained by a sudden change in system operating conditions (e.g., rapid acceleration), then T is determined. coil When a sensor's reliability decreases, its status is marked as "suspicious". Tcoil = "Suspicious"). If the deviation is extremely large (e.g., consistently exceeding 40°C), it can be directly determined as a "malfunction"; For motor lubricating oil temperature sensor (T) oil Diagnosis of ) Establish trend correlation logic: Oil temperature changes should have a logical correlation with motor load and ambient temperature. The controller continuously monitors T. oil The changing trend.

[0098] Fault diagnosis: Under sustained high load (such as P) motor After running at more than 60% of the rated power for a period of time (e.g., 5 minutes), T oil There should be a clear upward trend. If the Toil reading remains unchanged or even decreases at this point, its reliability is considered reduced (Flag). Toil = "suspicious"); Compare T oil With T env After the vehicle has been cold started, T oil It should gradually approach and eventually exceed T. env If T occurs for a long time oil Significantly and unreasonably lower than T env In such cases, its credibility is reduced (Flag). Toil = "suspicious").

[0099] Output reliability indicators: The controller maintains a confidence status flag for each critical sensor being diagnosed. This flag is updated in each control cycle and output to the subsequent decision-making module.

[0100] Flag states: typically include three states: "Normal": This indicates that the sensor data has passed all diagnostics and is highly reliable. "Suspicious": This indicates that the sensor data failed the physical plausibility diagnosis, but an anomaly was found in the relevance logic diagnosis. The reliability of the data is questionable, and a downgrade strategy is recommended. "Fault": This indicates that the sensor data is seriously abnormal, and it can be basically determined that the sensor has failed. Its data is unreliable, and a fault-tolerant control strategy must be activated.

[0101] Example: Flag Tcoil and Flag Toil These two variables will be set to one of the three states mentioned above.

[0102] Through the above multi-level diagnostics, the system can promptly identify soft faults (such as drift and performance degradation) or hard faults in sensors, providing crucial decision-making basis for the system to smoothly transition from "precise control" to "safe and fault-tolerant control", and greatly improving the reliability of the entire control system.

[0103] Step 3: Calculation of the environmental adaptive compensation factor: This step is crucial for achieving the adaptive capability of the control system. The system controller calculates a comprehensive environmental compensation factor (K) based on the collected external environmental parameters. env This is used to adjust the basic cooling requirements to offset the impact of changes in the external environment on the heat dissipation capacity of the electric drive system.

[0104] High temperature compensation factor (K) temp Calculation of ) Ambient temperature (T) env An increase in the temperature difference between the radiator and the outside air will reduce the temperature difference, leading to a decrease in heat dissipation efficiency. To compensate for this effect, the cooling demand needs to be increased; Set trigger threshold: Define a base ambient temperature threshold T envbase This value indicates that at this temperature and below, ambient temperature has no significant negative impact on heat dissipation efficiency, and no compensation is required. For example, T can be set. envbase = 25°C.

[0105] Define a computation function f1: Function f1 is a monotonically increasing function (increasing function) with input T. env The output is the high temperature compensation factor K. temp .

[0106] When T env ≤ T envbase At that time, K temp = 1.0; When T env >T envbase At that time, K temp Follow T env It increases as it rises.

[0107] Example of specific implementation: Method A (linear function): K temp = 1.0 + Kt (T env - T envbase ), where K t This is the high-temperature compensation factor (unit: 1 / °C), whose value is calibrated through bench testing of the heat dissipation system (e.g., K). t = 0.02 / °C, meaning that for every 1°C increase in ambient temperature, the required flow rate increases by 2%.

[0108] Method B (Table Lookup Method): A one-dimensional MAP table is pre-stored, with the horizontal axis representing the ambient temperature T. env The vertical axis represents the corresponding K. temp The compensation factor is obtained through table lookup and interpolation. This MAP table, calibrated experimentally, can more accurately describe nonlinear relationships.

[0109] Low pressure (high altitude) compensation factor (K pressure Calculation of ) Atmospheric pressure (P) env The decrease in altitude (corresponding to increased altitude) leads to a decrease in air density, which reduces the efficiency of cooling fans and the convective heat transfer coefficient of radiators, resulting in decreased heat dissipation efficiency. To compensate for this effect, cooling demand needs to be increased.

[0110] Set trigger threshold: Define a standard atmospheric pressure threshold P envbase (e.g., 101.325 kPa, corresponding to sea level pressure) or an altitude threshold H base (e.g., 1500 meters). Compensation is activated when the pressure is below this threshold (or the altitude is above this threshold).

[0111] Define the computation function f2: function f2 is a monotonically decreasing function (decreasing function) whose input is P. env The output is the low-pressure compensation factor Kpressure.

[0112] When P env ≥ P envbase (or H ≤ H) base When K pressure = 1.0; When P env <P envbase (or H>H) base When K pressure With P env It decreases and then increases.

[0113] Example of specific implementation: Method A (based on pressure ratio): K pressure = (P envbase / P env)^n. Where n is an empirical exponent, calibrated experimentally (e.g., n = 0.5~0.7). This formula is simplified based on the fan law and heat transfer relationships; Method B (based on altitude): If the altitude H is obtained, the formula can be used: K pressure = 1.0 + K h (H - H base (For H>H) base ), where K h Altitude compensation coefficient (unit: 1 / m); Method C (Table Lookup Method): Pre-store a one-dimensional MAP table, with P as the horizontal axis. env (or H), with the vertical axis corresponding to K. pressure value.

[0114] Comprehensive Environmental Compensation Factor (K) env Calculation of ) The effects of two environmental factors, high temperature and low air pressure, are combined into a total compensation factor.

[0115] Calculation formula: Comprehensive environmental compensation factor K env Synthesis is performed using a multiplicative model: K env = K temp K pressure ; Physical meaning: The multiplicative model implies that the negative effects of the two environments are superimposed and may be amplified. For example, in a high-altitude (low-pressure) region encountering high temperatures, heat dissipation efficiency will decrease sharply, requiring a larger compensation.

[0116] Lower limit: To ensure system security, K is set. env The lower limit is 1.0. That is, under extremely favorable conditions (theoretically calculated K), env (<1.0), the original required flow rate will still be executed, and the flow rate will not be reduced, in order to ensure the reliability of basic lubrication and cooling.

[0117] K env = max(K temp K pressure , 1.0); Based on the above calculations, the system obtains a compensation factor greater than or equal to 1.0. The more severe the environmental conditions (higher temperature, lower air pressure), the greater the compensation factor K. envA larger value will be used to amplify the basic cooling requirements in subsequent steps, thereby dynamically adapting to changes in the external environment and ensuring that the electric drive system maintains a reliable thermal balance under various geographical and climatic conditions. All thresholds, coefficients, and MAP data used in the calculations are pre-stored in the controller and calibrated through sufficient prior bench and road tests.

[0118] Step 4: Demand Flow Decision Based on Reliability and Environmental Compensation: This step is the core integration point of the entire control strategy. Here, the system controller integrates the sensor reliability indicators and environmental compensation factors obtained from previous steps to make the final demand flow decision. First, the controller obtains the basic demand flow (Q). demandbase This process follows the strategy outlined in the handover document: that is, real-time monitoring of various internal operating parameters (such as motor coil temperature T). coil Motor oil temperature T oil Motor torque (M), motor speed (RPM) motor (etc.) Each parameter is compared with its independent preset safety threshold. When any parameter exceeds the threshold, the system queries its specific preset "parameter-demand flow" mapping table or curve based on the specific value of the parameter exceeding the limit, calculates a corresponding temporary demand flow value, and finally selects the maximum value from all calculated temporary values ​​as Q. demandbase This strategy ensures that the base flow rate responds to the most pressing cooling demand. Following this, the controller applies environmental compensation to Q... demandbase The comprehensive environmental compensation factor K calculated in step three env Multiply to obtain the adaptive demand flow Q. demandenv =Q demandbase K env This operation aims to proportionally amplify cooling requirements based on the severity of external ambient temperature and pressure to compensate for decreased heat dissipation efficiency. Subsequently, the controller enters the fault-tolerant decision-making phase: if all critical sensors (such as T...) fail to meet the requirements... coil ,T oil Reliability flags Tcoil FlagT oil If all are "normal", then directly set Q to "normal". demandenv As the final demand flow Q demandfinal Output; if a key sensor (e.g., T) coil If a value is diagnosed as "faulty" or "suspected," a degradation strategy is initiated. Strategy one (model estimation) involves using its alternative estimate (e.g., the coil temperature estimate calculated from real-time motor power) to re-participate in the aforementioned basic flow decision process to calculate a new Q. demandbase Then environmental compensation is performed. Strategy two (conservative strategy) ignores the input of the faulty sensor and uses a preset fixed safety compensation coefficient K greater than 1.0.safe (e.g., K) safe =1.2) for Q demandenv To amplify it again, i.e., Q demandfinal = Q demandenv K safe This ensures that the system still receives sufficient cooling and lubrication even in the conservative scenario of sensor failure; if the faulty sensor is an oil temperature sensor (T... oil If the fault condition is not addressed in this step, it will be recorded and used in the subsequent flow calibration control in step six, at which time oil temperature-based compensation adjustment will be paused. The final output Q demandfinal It is a robust and adaptive cooling requirement command that fully considers real-time heat load, external environmental conditions, and sensor health status.

[0119] Step 5, Target Speed ​​Inquiry and Closed-Loop Control: This step follows the output of Step 4, and its target is the comprehensive demand flow Q, which is finally determined after environmental adaptive compensation and fault-tolerant decision-making. demandfinal First, the system controller uses Q... demandfinal As input, the system queries its internally stored electronic oil pump flow-speed MAP (Map of Flow Rates and Speeds). This MAP data, calibrated through prior bench tests, establishes the correspondence between flow rate and speed at a specific reference oil temperature. The controller then uses a lookup table and interpolation to obtain a precise target electronic oil pump speed (RPM) corresponding to the current final required flow rate. target Subsequently, the system enters the speed closed-loop control stage, the core purpose of which is to drive the actual speed (RPM) of the electronic oil pump. actual Precisely track the target rotational speed (RPM) target The closed-loop control logic is as follows: the controller reads the actual rotational speed (RPM) fed back by the electronic oil pump in real time. actual And calculate its ratio with the target speed in RPM. target The absolute value of the deviation |ΔRPM| = |RPM actual - RPM target The deviation is compared with a preset first tolerance M (e.g., 50 RPM). If |ΔRPM| is less than M, the speed control accuracy is deemed to meet the requirements, and the current control current output remains unchanged. If |ΔRPM| is greater than or equal to M, the control current output to the electronic oil pump is adjusted according to the direction of the deviation, using a preset fixed current step value N (e.g., 0.05A). If the actual speed is too low (RPM... actual <RPM target Then step-increment adjustment (I) is performed. controlnew = I controlold + N), if the actual speed is too high, then perform step reduction adjustment (I).controlnew = I controlold -N). This "measurement-comparison-correction" process is executed cyclically within each control cycle (e.g., 1ms), thus forming a dynamic feedback closed loop to ensure that the actual speed of the electronic oil pump remains stable within the target speed tolerance range (RPM). target Within ± M), it ultimately provides a precise and stable supply of cooling and lubricating oil to the vehicle's oil-cooled electric drive system.

[0120] Step Six: Fault-Aware Flow Calibration Control: This step serves as a fine-tuning process after the speed closed-loop control. Its execution relies on judging the reliability status of the oil temperature sensor, aiming to correct flow output deviations caused by changes in oil viscosity with temperature. The system controller first checks the reliability flag from Step Two. Toil If the flag displays "Normal", it indicates that the oil temperature sensor data is reliable and the controller will execute normally as per the instructions. Figure 3 The oil temperature compensation steps shown are as follows: The specific process involves real-time reading of the motor lubricating oil temperature T. oilactual Calculate its relationship with the pre-stored flow-speed MAP calibration base oil temperature T. base Temperature difference ΔT = T oilactual - T base The controller sets the absolute value of the current, |ΔT|. When |ΔT| is less than the second set tolerance M1, the current control current remains unchanged. When ΔT is significantly greater than M1, the control current is adjusted by decreasing the preset step size to compensate for the excessive flow caused by the thinning of the oil. When ΔT is significantly less than -M1, the control current is adjusted by increasing the step size to compensate for the excessive flow caused by the thickening of the oil. This ensures that the actual output flow of the electronic oil pump at different oil temperatures can accurately match the target flow requirement. If the controller detects a Flag... Toil If the flag is set to "Fault," the oil temperature sensor is deemed to have failed, and fault-tolerant operation is immediately initiated: the entire dynamic compensation adjustment based on oil temperature is skipped, and an alarm message is sent to the instrument panel or diagnostic system via the CAN bus to alert the driver or maintenance personnel. At this point, the system degrades to relying solely on the speed closed-loop control from step five to maintain flow. Although it cannot correct for the viscosity effects caused by oil temperature changes, the accuracy of speed control still provides a basically reliable flow guarantee. As an optional enhanced fault-tolerant strategy, the system can also use a fixed default oil temperature value (e.g., 80°C) in the compensation calculation process for lookup and adjustment to provide an approximate compensation effect. This step ensures that the flow calibration function can provide accurate compensation when the sensor is healthy, and gracefully degrade when the sensor fails, maximizing the system's continuous operational capability.

[0121] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method of controlling an electric oil pump of a vehicle oil-cooled electric drive system, characterized by, The method comprises the following steps, acquiring at least two operating parameters of a vehicle oil-cooled electric drive system, the operating parameters including a temperature parameter and a load-related parameter; determining a required flow rate of an electronic oil pump based on the at least two operating parameters; querying pre-stored flow rate and speed MAP data according to the required flow rate to obtain a corresponding target speed of the electronic oil pump; adjusting a control current of the electronic oil pump based on the target speed to control an actual speed of the electronic oil pump, thereby providing the required flow rate.

2. The electronic oil pump control method of a vehicle oil-cooled electric drive system according to claim 1, characterized by: The temperature parameter includes a motor coil temperature and / or a motor lubricating oil temperature; and the load-related parameter includes one or more of a motor torque, a motor speed and a motor power.

3. The electronic oil pump control method of the vehicle oil-cooled electric drive system according to claim 1 or 2, characterized in that: determining a required flow rate of an electronic oil pump based on the at least two operating parameters, specifically: comparing the at least two operating parameters with preset threshold values respectively; when any operating parameter exceeds its corresponding threshold value, determining a demand target speed according to the parameter, and taking the maximum value of all determined demand target speeds as a final target speed of the electronic oil pump.

4. The electronic oil pump control method of the vehicle oil-cooled electric drive system according to claim 1, characterized in that: the step of adjusting the control current of the electronic oil pump adopts a closed-loop control mode, comprising: real-time acquisition of an actual speed of the electronic oil pump; calculation of a difference between the actual speed and the target speed; when an absolute value of the difference is greater than a first set tolerance, step-up or step-down adjustment of the control current is performed according to a positive or negative of the difference by a preset step size.

5. The electronic oil pump control method of a vehicle oil-cooled electric drive system according to claim 4, characterized by: further comprising a flow rate calibration step: real-time acquisition of an actual oil temperature of the electric drive system; calculation of a difference between the actual oil temperature and a preset base oil temperature; when an absolute value of the temperature difference is greater than a second set tolerance, compensation adjustment of the control current is performed according to a positive or negative of the temperature difference to correct an output flow rate deviation of the oil pump caused by a change in the oil temperature.

6. The electronic oil pump control method of a vehicle oil-cooled electric drive system according to claim 4, characterized by: The compensation adjustment of the control current is specifically performed by querying a pre-stored speed, current and flow rate three-dimensional MAP data table that takes into account the influence of the oil temperature.

7. The electronic oil pump control method of a vehicle oil-cooled electric drive system according to claim 4, characterized by: The compensation adjustment of the control current is specifically performed by performing additional step-up or step-down adjustment of a current control current value determined by the speed closed-loop control according to the temperature difference and a preset rule.

8. An electronic oil pump control system for a vehicle oil-cooled electric drive system, the system comprising: The system for implementing the method according to any one of claims 1-7 comprises: a sensor module for collecting the at least two operating parameters; a controller electrically connected to the sensor module and the electronic oil pump, and internally storing the flow rate and speed MAP data; the controller is configured to: receive the operating parameters; determine a required flow rate of an electronic oil pump based on the at least two operating parameters; query the flow rate and speed MAP data to obtain a corresponding target speed of the electronic oil pump; and output a control signal based on the target speed to adjust a control current of the electronic oil pump.

9. The electronic oil pump control system of a vehicle oil-cooled electric drive system of claim 8, wherein: The controller is further configured to perform speed closed-loop control by real-time acquisition of an actual speed of the electronic oil pump; calculation of a difference between the actual speed and the target speed; When the absolute value of the difference is greater than a first set tolerance, the control current is adjusted to make the actual rotation speed approach the target rotation speed.

10. The electronic oil pump control system of a vehicle oil-cooled electric drive system of claim 9, wherein: The controller is further configured to perform flow calibration control: An actual oil temperature of the electric drive system is acquired in real time; A difference between the actual oil temperature and a preset base oil temperature is calculated; When the absolute value of the temperature difference is greater than a second set tolerance, the control current is adjusted to compensate for the deviation of the oil pump output flow caused by the change of the oil temperature.

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