Torque control method, computer device, readable storage medium and motor vehicle

Abstract

The present invention discloses a torque control method, computer equipment, a readable storage medium, and a motor vehicle, relating to the field of automotive technology. The method comprises the following steps: a motor controller calculates the power module junction temperature based on the three-electric operating parameters and the water pump gear position, and calculates a first limiting torque based on the power module junction temperature; the motor controller obtains a current limit value based on the three-electric operating parameters and the water pump gear position, and calculates a second limiting torque based on the current limit value; and the smaller of the first limiting torque and the second limiting torque is used as the output torque. The torque control method provided by the present invention can adjust the torque output and the water pump gear position in real time according to the vehicle's operating conditions.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and in particular to a torque control method, computer equipment, a readable storage medium, and a motor vehicle. Background Art

[0002] Currently, more and more automakers are launching hybrid electric vehicles, plug-in hybrid electric vehicles, extended-range electric vehicles, and pure electric vehicles. These vehicles are equipped with a motor, a battery pack to provide energy to the motor, and a motor controller to control the motor.

[0003] The vehicle control unit (VCU) collects the position signal of the driver's accelerator pedal, analyzes it, and issues a torque command to the motor controller (MCU). The battery pack provides DC power to the motor controller, with the output voltage varying with the SOC. Upon receiving the torque command, the motor controller controls the output of three-phase current to the drive motor, thereby controlling the output torque of the drive motor. At this time, various operating parameters of the vehicle are changing in real time. Therefore, both heat dissipation and torque output need to be adjusted based on the vehicle's real-time conditions. Conventional technology uses a fixed controller output current limit for torque output. Simultaneously, the coolant pump used for heat dissipation also uses a fixed flow rate control mechanism. This approach fails to form a closed-loop linkage between output torque, power module junction temperature, and coolant pump flow control, and therefore cannot be adjusted in real time based on vehicle operating parameters. This not only increases energy consumption when high-level heat dissipation is not required, but also makes it difficult to adjust the heat dissipation level in a timely manner when it is required. This leads to heat accumulation, which can damage components such as IGBTs, diodes, and motors, posing a safety hazard. Summary of the Invention

[0004] To solve the aforementioned problems, the present invention provides a torque control method that adjusts the torque output and water pump gear position in real time according to the operating conditions of the vehicle.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A torque control method, characterized in that the torque control method comprises the following steps:

[0007] The motor controller calculates the power module junction temperature based on the three-electric operation parameters and the water pump gear position, and calculates the first limit torque based on the power module junction temperature. The three-electric operation parameters include the coolant flow rate. The coolant flow rate has several threshold values, and the water pump gear position is divided by the coolant flow rate threshold value.

[0008] The motor controller obtains the current limit value according to the three-electric operation parameters and the water pump gear position, and calculates the second limited torque according to the current limit value;

[0009] The smaller value of the first limit torque and the second limit torque is used as the output torque.

[0010] The technical solution provided by the present invention calculates the junction temperature of the power module in real time according to the operating conditions of the entire vehicle, and calculates the output torque based on it, and compares the torque of the current limit at the same time. The two are compared and outputted, which can avoid vehicle jerking caused by excessive output torque and the resulting heat accumulation, and can also avoid insufficient power caused by small output torque and the resulting waste of heat dissipation energy.

[0011] Optionally, the motor controller calculates the power module junction temperature according to the three-electric operation parameters and the water pump gear position, and calculates the first limiting torque according to the power module junction temperature, including the following steps:

[0012] Critical junction temperature calculation: Calculates the power module junction temperature corresponding to each critical coolant flow rate based on the three-electric operating parameters, including the IGBT switching frequency and motor speed.

[0013] Junction temperature calculation: Calculate the power module junction temperature corresponding to the current coolant flow rate based on the current coolant flow rate, the coolant flow rate cutoff value corresponding to the current water pump gear position, and the power module junction temperature corresponding to the cutoff value;

[0014] Adjustment: Obtain the first limit torque according to the motor speed and the power module junction temperature corresponding to the current coolant flow rate.

[0015] Dynamic estimation of the power module junction temperature enables more effective protection against excessive junction temperatures, improves junction temperature torque limits, and fully utilizes the hardware's current capability. After the junction temperature torque limit is reached, the IGBT switching frequency is proactively adjusted and the vehicle's water pump gear is increased to reduce the junction temperature, avoid junction temperature torque limits, and further enhance hardware safety.

[0016] Optionally, calculate the power module junction temperature corresponding to the current coolant flow rate using the following formula:

[0017] Tj=Tj n +(Tj n+1 -Tj n ) / (L n+1 -L n )*(LL n )

[0018] Among them, Tj is the power module junction temperature corresponding to the current coolant flow, n is the current water pump gear and the corresponding gear demarcation value sequence number, Tj n is the power module junction temperature corresponding to the coolant flow rate cutoff value, L is the current coolant flow rate, and Ln is the coolant flow rate cutoff value.

[0019] The junction temperature of the power module is calculated by interpolation, which improves the accuracy of the junction temperature calculation, avoids the situation where the estimated junction temperature is lower than the actual junction temperature at low flow, and protects the safety of the module.

[0020] Optionally, calculating the power module junction temperature corresponding to each cutoff value of the coolant flow rate includes the following steps:

[0021] Calculate the conduction loss of the IGBT chip for each bridge arm according to the following formula:

[0022]

[0023] Among them, P cond,IGBT is the conduction loss of the IGBT chip, t is the time, T0 is the working cycle of the chip, τ(t) is the duty cycle of the IGBT chip, V ce (t) is the voltage between the collector and emitter of the IGBT, V ce0 IGBT output characteristic curve I c =f(V ce ) The tangent line of the midline segment is extended to V ce The value at the intersection, r ce IGBT output characteristic curve I c =f(V ce ) is the slope of the tangent line of the linear segment, I m is the current amplitude, ω is the angular velocity, m is the modulation ratio, is the phase angle;

[0024] Calculate the switching loss of the IGBT chip for each bridge arm according to the following formula:

[0025]

[0026] Among them, P SW,IGBT is the switching loss of the IGBT chip, f sw is the switching frequency, E on (I nom ,V nom ) is the typical operating condition opening loss, E off (I nom ,V nom ) is the typical operating condition turn-off loss, V dc is the battery voltage;

[0027] Calculate the junction temperature of the IGBT chip for each bridge arm according to the following formula:

[0028]

[0029] Among them, Tj IGBT is the junction temperature of the IGBT chip, P IGBTis the total loss of the IGBT chip, R th,IGBT is the thermal resistance from IGBT chip to coolant, T w is the coolant temperature.

[0030] Calculate the conduction loss of the diode chip for each bridge arm according to the following formula:

[0031]

[0032] Among them, P cond,Diode is the conduction loss of the diode chip, t is the time, T0 is the working cycle of the chip, τ'(t) is the duty cycle of the diode chip, V F (t) is the forward voltage of the diode, V F0 The diode characteristic curve I F =f(V F ) The tangent line of the midline segment is extended to V F The value at the intersection, r F The diode characteristic curve I F =f(V F ) is the slope of the tangent line of the linear segment, I m is the current amplitude, ω is the angular velocity, m is the modulation ratio, is the phase angle;

[0033] Calculate the switching loss of the diode chip for each bridge arm according to the following formula:

[0034]

[0035] Among them, P sw,Diode is the switching loss of the diode chip, f sw is the switching frequency, E on (I nom ,V nom ) is the typical operating condition opening loss, E off (I nom ,V nom ) is the typical operating condition turn-off loss, V dc is the battery voltage;

[0036] Calculate the junction temperature of the diode chip for each bridge arm according to the following formula:

[0037]

[0038] Among them, Tj DIode is the junction temperature of the diode chip, P Diode is the total loss of the diode chip, R th,IGBT is the thermal resistance from the diode chip to the coolant, T w is the coolant temperature;

[0039] The larger value of the junction temperature of the IGBT chip and the junction temperature of the diode chip in each bridge arm is taken as the junction temperature of the bridge arm;

[0040] Among the junction temperatures of all bridge arms, the maximum junction temperature is taken as the junction temperature of the power module.

[0041] Optionally, after calculating the first limiting torque based on the power module junction temperature, it is determined whether the power module junction temperature corresponding to the current coolant flow exceeds the junction temperature limit, and the amplitude of reducing the switching frequency is selected based on the exceeded junction temperature limit.

[0042] After calculating the first limiting torque based on the power module junction temperature, the IGBT switching frequency is actively adjusted to reduce the junction temperature and avoid further junction temperature torque limiting. This provides additional means to reduce the power module junction temperature and optimizes the power module overtemperature protection strategy.

[0043] Optionally, the motor controller obtains a current limit value according to the three-electric operation parameters, and calculates the second limited torque according to the current limit value, including the following steps:

[0044] Initial setting: Get the current initial output current limit value based on the three-electric operation parameters and the water pump gear position;

[0045] Determination: The three-electric operation parameters include the opening of the accelerator pedal. Whether the current initial output current limit needs to be limited is determined based on the opening of the accelerator pedal. When the opening of the accelerator pedal is greater than or equal to a first preset opening, the current initial output current limit is adopted. When the opening of the accelerator pedal is less than the first preset opening, the current initial output current limit is reduced to form a process output current limit.

[0046] Limitation: The second limiting torque is determined based on the current motor speed and the initial output current limit or the process output current limit.

[0047] The technical solution provided by the present invention can determine

[0048] Based on the vehicle's operating conditions, the system determines the maximum available peak output current under current conditions, dynamically limiting the peak current output by the motor controller and thus controlling the motor's torque. This maximizes the motor controller's capabilities while ensuring system safety and reliability. Furthermore, the accelerator pedal, acting as a proxy for driver intent, further limits the motor controller's current when high power performance is not required, ensuring hardware safety.

[0049] Optionally, the torque control method further includes a thermal management system controlling a coolant pump gear according to three-electric operation parameters, including:

[0050] The three electric operating parameters include VCU requested torque, power module NTC temperature, motor temperature, and water inlet temperature. Obtain the VCU requested torque, power module NTC temperature, motor temperature, water inlet temperature, power module junction temperature, and the required water pump gear position, and take the maximum value among them.

[0051] Determining a driver's required torque based on the motor speed and the accelerator pedal opening, where the driver's required torque is the product of the accelerator pedal opening and a maximum torque limit, where the maximum torque limit is obtained from the motor speed, and determining an adjustment value for the coolant water pump gear based on the required torque;

[0052] The sum of the maximum value and the adjustment value is used as the output pump gear.

[0053] Based on the three-electric operating parameters, such as VCU requested torque, motor temperature, water inlet temperature, power module NTC temperature, power module junction temperature, etc., as well as the required water pump gear, the current required water pump level is dynamically evaluated, and autonomous control of the water pump level is achieved. The response speed of the cooling flow is improved, which is more refined than the thermal management assessment of the whole vehicle. Under the premise of meeting the heat dissipation requirements, the low-power operation of the water pump is achieved as much as possible, saving energy consumption.

[0054] Optionally, if the driver's required torque is greater than or equal to the second limiting torque, the adjustment value of the water pump gear is 1 and the timing is started at the same time, otherwise the adjustment value of the water pump gear is 0. If the timing time is greater than the preset time, the adjustment value of the water pump gear is 2.

[0055] By comparing the driver's required torque and the junction temperature torque limit, it is assessed whether insufficient coolant flow is causing the motor controller's torque limit. The water pump gear is increased to reduce the torque limit, achieving automatic adjustment.

[0056] Optionally, after the sum of the maximum value and the adjustment value is used as the output water pump gear, it is determined whether the opening of the accelerator pedal is greater than a second preset opening. If it is, the lower limit value of the water pump gear is set to 3, otherwise the water pump gear remains unchanged.

[0057] The accelerator pedal's opening is a crucial indicator of driver intent. There's a delay between the driver pressing the accelerator pedal and the VCU outputting the requested torque. The technical solution provided by this invention proactively controls the water pump level, avoiding the risk of overheating due to delayed cooling. It also prevents the water pump from operating at high power when high cooling power isn't needed, saving energy.

[0058] Optionally, determine the junction temperature level range of the power module junction temperature corresponding to the coolant flow rate. If the water pump gear corresponding to the junction temperature level range is lower than the output water pump gear, maintain the current output water pump gear. If the water pump gear corresponding to the junction temperature level range is higher than the output water pump gear, use the water pump gear corresponding to the junction temperature level range as the output water pump gear.

[0059] Optionally, if the water pump gear corresponding to the junction temperature level interval is used as the output water pump gear, the first limiting torque and the second limiting torque are recalculated according to the adjusted water pump gear.

[0060] After adjusting the coolant water pump gear, since the water pump gear changes, the first limiting torque and the second limiting torque are readjusted according to the changed gear, so that the limiting is more accurate, and the entire adjustment method forms a closed loop.

[0061] Optionally, the VCU requested torque, power module junction temperature, power module NTC temperature, motor temperature and water inlet temperature are respectively provided with gear boundary values, and the gear boundary value, the boundary value of the coolant flow rate, the first preset opening, the second preset opening and the second limiting torque are respectively provided with hysteresis coefficients.

[0062] The hysteresis coefficient is used to avoid repeated jumping of the water pump gear position when the aforementioned physical quantities change.

[0063] In addition, the present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements any of the above-mentioned torque control methods when executing the computer program.

[0064] At the same time, the present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, any of the above-mentioned torque control methods is implemented.

[0065] Furthermore, the present invention further provides a motor vehicle having a motor and a motor controller, wherein the motor controller outputs torque to the motor using any one of the torque control methods described above.

[0066] or the motor vehicle has the aforementioned computer device;

[0067] Or the motor vehicle has the aforementioned computer-readable storage medium, and when the computer program is executed by a processor, any one of the aforementioned torque control methods is implemented.

[0068] These features and advantages of the present invention will be further disclosed in the following detailed description and accompanying drawings. The preferred embodiments and means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present in each of the following text and accompanying drawings, they may be labeled with different symbols or numbers for convenience, but all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The present invention will be further described below in conjunction with the accompanying drawings:

[0070] Figure 1 Schematic diagram of a flow chart in an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The following is an explanation and description of the technical solutions of the embodiments of the present invention in conjunction with the drawings of the embodiments of the present invention. However, the following embodiments are only preferred embodiments of the present invention and are not exhaustive. Based on the embodiments in the implementation manner, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0072] Reference throughout this specification to "one embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment itself may be included in at least one embodiment of the present disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0073] Example:

[0074] like Figure 1 As shown, this embodiment provides a torque control method. The torque control method provided in this embodiment is used for hybrid electric vehicles, plug-in hybrid electric vehicles, extended-range electric vehicles and pure electric vehicles. The above types of vehicles are equipped with a motor, a battery pack that provides energy to the motor, and a motor controller that controls the motor. At the same time, it is also equipped with a water pump and a cooling water channel for dissipating heat for the battery, motor and motor controller. The motor controller limits the output torque of the motor through the torque control method provided in this embodiment. In general, the torque control method provided in this embodiment includes the following steps:

[0075] The motor controller calculates the power module junction temperature according to the three-electric operation parameters and the water pump gear position, and calculates the first limit torque according to the power module junction temperature;

[0076] The motor controller obtains the current limit value according to the three-electric operation parameters and the water pump gear position, and calculates the second limited torque according to the current limit value;

[0077] The smaller value of the first limit torque and the second limit torque is used as the output torque.

[0078] Specifically, the three electrics refer to batteries, motors, and electronic controls. In this embodiment, the three electric operating parameters include but are not limited to coolant flow, duty cycle, current, battery voltage, motor speed, coolant inlet temperature, accelerator pedal opening, motor temperature, power module NTC temperature, VCU requested torque, IGBT switching frequency, etc. Those skilled in the art should know that during the actual operation of the vehicle, all physical quantities that can characterize the three electric operating states can be used as three electric operating parameters. The coolant flow has several coolant flow boundary values, and the water pump gear is divided by the boundary value. The current water pump gear can be determined based on the current coolant flow and the coolant flow boundary value, and the first limiting torque is calculated in combination with the power module junction temperature. This step includes the following sub-steps:

[0079] Calculation of junction temperature at critical values: Calculate the power module junction temperature corresponding to each critical value of the coolant flow rate based on the three-electric operating parameters. First, calculate the conduction loss of the IGBT chip for each bridge arm according to the following formula:

[0080]

[0081] Among them, P cond,IGBT is the conduction loss of the IGBT chip, t is the time, T0 is the working cycle of the chip, and each phase of the upper or lower bridge IGBT only works for half a cycle in one cycle. τ(t) is the duty cycle of the IGBT chip conduction, V ce (t) is the voltage between the collector and emitter of the IGBT, where V ce It can also be obtained by looking up the table in the specification or measured data. ce0 IGBT output characteristic curve I c =f(V ce ) The tangent line of the midline segment is extended to V ce The value at the intersection, r ce IGBT output characteristic curve I c =f(V ce ) The slope of the tangent line of the linear segment and the IGBT output characteristic curve are also common technical knowledge known to those skilled in the art and will not be described in detail here. m is the current amplitude, ω is the angular velocity, m is the modulation ratio, is the phase angle;

[0082] Then calculate the switching loss of the IGBT chip for each bridge arm according to the following formula:

[0083]

[0084] Among them, P SW,IGBT is the switching loss of the IGBT chip, f sw is the switching frequency, Eon (I nom ,V nom ) is the typical operating condition opening loss, E off (I nom ,V nom ) is the typical operating condition turn-off loss. The typical operating condition turn-on loss or turn-off loss is a common technical knowledge known to those skilled in the art and will not be described in detail here. dc is the battery voltage. The switching loss of the IGBT chip can also be obtained by looking up the data sheet or measured data.

[0085] Then calculate the junction temperature of the IGBT chip for each bridge arm according to the following formula:

[0086]

[0087] Among them, Tj IGBT is the junction temperature of the IGBT chip, P IGBT is the total loss of the IGBT chip, R th,IGBT is the thermal resistance of the coolant to the IGBT chip, T w is the coolant temperature. The thermal resistance R of the coolant of the IGBT chip th,IGBT It is negatively correlated with the coolant flow rate, that is, the greater the coolant flow rate, the greater the thermal resistance R th,IGBT The smaller.

[0088] The junction temperature of the diode chip is calculated in the same way. First, the conduction loss of the diode chip is calculated for each bridge arm according to the following formula:

[0089]

[0090] Among them, P cond,Diode is the conduction loss of the diode chip, t is the time, T0 is the working cycle of the chip, τ'(t) is the duty cycle of the diode chip, V F (t) is the forward conduction voltage of the diode, which can also be obtained from the specification sheet or measured data. V F0 The diode characteristic curve I F =f(V F ) The tangent line of the midline segment is extended to V F The value at the intersection, r F The diode characteristic curve I F =f(V F ) is the slope of the tangent line of the linear segment, I m is the current amplitude, ω is the angular velocity, m is the modulation ratio, is the phase angle;

[0091] Then calculate the switching loss of the diode chip for each bridge arm according to the following formula:

[0092]

[0093] Among them, P sw,Diode is the switching loss of the diode chip, f sw is the switching frequency, E on (I nom ,V nom ) is the typical operating condition opening loss, E off (I nom ,V nom ) is the typical operating condition turn-off loss, V dc is the battery voltage. The switching loss of the diode chip can also be obtained by looking up the data in the specification or measured data.

[0094] Then calculate the junction temperature of the diode chip for each bridge arm according to the following formula:

[0095]

[0096] Among them, Tj DIode is the junction temperature of the diode chip, P Diode is the total loss of the diode chip, R th,Diode is the thermal resistance of the cooling fluid to the diode chip, T w is the coolant temperature. The thermal resistance of the coolant to the diode chip is R th,Diode It is negatively correlated with the coolant flow rate, that is, the greater the coolant flow rate, the greater the thermal resistance R of the diode chip. th,Diode The smaller.

[0097] After calculating the junction temperature of the IGBT chip and the junction temperature of the diode chip in each bridge arm, the larger value of the two is taken as the junction temperature of the bridge arm. Among the junction temperatures of all bridge arms, the maximum junction temperature is taken as the junction temperature of the power module.

[0098] Junction temperature calculation: Based on the current coolant flow rate, the coolant flow rate cutoff value corresponding to the current water pump gear, and the power module junction temperature corresponding to the cutoff value, calculate the power module junction temperature corresponding to the current coolant flow rate according to the following formula:

[0099] Tj=Tj n +(Tj n+1 -Tj n ) / (L n+1 -L n )*(LL n )

[0100] Among them, Tj is the power module junction temperature corresponding to the current coolant flow, n is the current water pump gear and the corresponding gear demarcation value sequence number, Tj nThe power module junction temperature corresponding to the coolant flow rate cutoff value, L represents the current coolant flow rate, and Ln represents the coolant flow rate cutoff value. For example, if n = 2, the current water pump gear is set to gear 2. L2 represents the flow rate at the starting point of gear 2, which is also the second cutoff value for the flow rate. TJ2 represents the power module junction temperature corresponding to the starting flow rate of gear 2. L3 represents the flow rate at the end point of gear 2, which is also the third cutoff value for the flow rate. It is also the flow rate at the starting point of gear 3. TJ3 represents the power module junction temperature corresponding to the ending flow rate of gear 2. By calculating the power module junction temperature through interpolation, the accuracy of the junction temperature calculation is improved, preventing the estimated junction temperature from being lower than the actual junction temperature at low flow rates, thus protecting the module safety.

[0101] Adjustment: The first limiting torque is obtained based on the motor speed and the power module junction temperature corresponding to the current coolant flow rate. The first limiting torque is determined by table lookup combined with interpolation. Specifically in this embodiment, the relationship between the motor speed, the power module junction temperature corresponding to the current coolant flow rate, and the junction temperature torque limit is as follows:

[0102]

[0103] For example, if the current power module junction temperature Tj is 147.8° C. and the motor speed is 4000 r / min, the first limiting torque is calculated to be 317.6 Nm by interpolation after looking up the table.

[0104] It should be noted that this implementation targets compact vehicles, including compact sedans and compact SUVs. When dealing with other vehicle types, such as mid-sized and mid-to-large vehicles, the junction temperature torque limit can be adaptively adjusted by those skilled in the art during commissioning and calibration based on the actual vehicle model. This adjustment method can utilize a general junction temperature estimation method based on models and bench calibration. This is well-known in the art and is not limited here. Those skilled in the art should be aware that the junction temperature torque limit values ​​in this table are merely preferred methods specific to this embodiment and do not limit the technical solution.

[0105] Then, the switching frequency of the IGBT is adjusted according to the obtained first limiting torque, including:

[0106] Determine whether the junction temperature of the power module corresponding to the current coolant flow exceeds the junction temperature limit, and select the amplitude of reducing the switching frequency according to the exceeded junction temperature limit. There are several junction temperature limits, and the switching frequency of the IGBT corresponding to different junction temperatures. Specifically in this embodiment, the relationship between the junction temperature limit and the switching frequency of the IGBT is as follows:

[0107] Junction temperature Switching frequency 140℃ 10kHZ 145℃ 9kHZ 150℃ 8kHZ

[0108] It should also be noted that the vehicle models targeted by this implementation are compact vehicles, including compact sedans and compact SUVs. When faced with other different vehicle models such as mid-sized vehicles and medium-to-large vehicles, the relationship between the junction temperature limit and the IBGT switching frequency, as well as the relationship between the junction temperature level range and the water pump gear position, can be adaptively adjusted by those skilled in the art during debugging and calibration based on the actual vehicle model. The specific adjustment methods are well-known existing technologies in the art and are not limited here. Those skilled in the art should be aware that the maximum torque limit values ​​in this table are only preferred methods specific to this embodiment and do not limit the technical solution.

[0109] The technical solution provided by this embodiment dynamically estimates the power module junction temperature, providing more effective protection against excessive junction temperatures. This improves the junction temperature torque limit and fully utilizes the hardware's current capability. After calculating the first limiting torque, the switching frequency is actively adjusted to reduce the junction temperature, avoiding junction temperature torque limit and further improving hardware safety.

[0110] The calculation of the second limiting torque specifically includes the following sub-steps:

[0111] Initial determination: The current initial output current limit is obtained based on the water inlet temperature, water pump gear and battery voltage. In this step, the water inlet temperature, water pump gear and battery voltage are also respectively provided with gear boundary values. After obtaining the water inlet temperature, the coolant water pump gear and the battery voltage, the gear interval in which each physical quantity is currently located is determined according to each gear boundary value, and the initial output current limit is determined by looking up the table. Specifically in this embodiment, the relationship between the water inlet temperature, water pump gear and battery voltage and their respective gear boundary values ​​and the initial output current limit is as follows:

[0112]

[0113] For example, if the current water inlet temperature is 45°C, the water pump gear is L3, that is, the coolant flow rate is 12L / min, and the battery voltage is 350V, the initial output current limit is 590A.

[0114] It should be noted that the vehicle model targeted by this implementation is a compact vehicle, including a compact sedan and a compact SUV. When faced with other different vehicle models such as mid-sized vehicles and medium-to-large vehicles, the initial output current limit value can be adaptively adjusted by those skilled in the art according to the actual vehicle model during debugging and calibration. The adjustment method can adopt the current capacity bench calibration method of the comprehensive electrothermal coupling working condition module. This is a prior art known in the art and is not limited here. Those skilled in the art should know that the initial output current limit value in this table is only a preferred method specific to this embodiment, and is not a limitation of the technical solution.

[0115] Through these initial steps, the motor controller's capabilities are maximized while ensuring system safety and reliability. Under favorable vehicle conditions (i.e., low water temperature, high flow rate, and low voltage), a higher current can be output to fully utilize the hardware's characteristics. Under adverse vehicle conditions (i.e., low water temperature, high flow rate, and low voltage), the output current is limited to ensure hardware safety and reliability.

[0116] At the same time, a hysteresis coefficient is set for each gear boundary value. During vehicle operation, the water inlet temperature, water pump gear position, and battery voltage rise and reach the corresponding gear boundary value before the vehicle shifts to the next gear. Since each physical quantity changes in real time, the water inlet temperature, water pump gear position, and battery voltage may all decrease. Once they drop to the gear boundary value, the vehicle shifts back to the previous gear. If the physical quantity fluctuates near the gear boundary value, gear jitter will occur. This will cause the initial output current limit output by the motor controller to fluctuate. In this embodiment, hysteresis coefficients are set for the water inlet temperature, water pump gear position, and battery voltage. This ensures that the gear boundary value reached during a rise and fall differs. Only when the actual value of the gear boundary value reached during a fall is less than the actual value of the gear boundary value reached during a rise can the vehicle shift back to the previous gear. This prevents gear jitter caused by physical quantity fluctuations near the gear boundary value, thereby maintaining the initial output current limit output by the motor controller stable and preventing fluctuations.

[0117] Determination: Obtain the current accelerator pedal opening and, based on this opening, determine whether the current initial output current limit needs to be restricted. When the accelerator pedal opening is greater than or equal to a first preset opening, the current initial output current limit is used. When the accelerator pedal opening is less than the first preset opening, the current initial output current limit is reduced to form a process output current limit. The accelerator pedal opening serves as a proxy for driver intent. When low-power performance is not required, the motor controller output current is further restricted to ensure hardware safety. Specifically, in this embodiment, the first preset opening is 80% of the maximum accelerator pedal opening. In other embodiments, the first preset opening can be flexibly set by those skilled in the art during calibration and adjustment, and is not limited here. When the accelerator pedal opening is less than 80%, the initial output current limit is reduced from 590 Arms to 540 Arms to form the process output current limit. When the accelerator pedal opening is ≥80%, no further reduction is made and the initial output current limit of 590 Arms is maintained. The extent to which the initial output current limit is reduced can be flexibly set by those skilled in the art based on conditions such as the vehicle model, motor model, and battery capacity, and will not be further elaborated herein. In this step, a hysteresis coefficient is also set for the first preset opening. When the accelerator pedal opening decreases back to the first preset opening, the hysteresis coefficient is set. Therefore, when the actual value of the first preset opening reached during the decrease in the accelerator pedal opening is less than the actual value of the first preset opening reached during the increase in the accelerator pedal opening, the initial output current limit value before the decrease is returned. This stabilizes the initial output current limit output by the motor controller and prevents fluctuations.

[0118] Limiting: The second limiting torque is determined based on the current motor speed and the initial output current limit or the process output current limit. After the two physical quantities of speed and current limit are obtained, the interval gear position where the obtained speed and current limit are located is determined based on the interval gear position divided by the two physical quantities, and then the second limiting torque is determined by looking up the table. Because the current output by the motor controller is positively correlated with the torque output by the motor, limiting the maximum torque of the motor controller can limit the output current, thereby protecting the hardware safety. Specifically in this embodiment, the relationship between the gear range of the speed and current limit and the torque limit is as shown in the following table:

[0119]

[0120] It should also be noted that this embodiment targets compact vehicles, including compact sedans and compact SUVs. When dealing with other vehicle types, such as mid-sized and mid-to-large vehicles, the torque limiter can be adaptively adjusted by those skilled in the art during commissioning and calibration based on the actual vehicle model. The specific adjustment methods are well known in the art and are not limited here. Those skilled in the art should be aware that the torque limiters in this table are merely preferred methods specific to this embodiment and do not limit the technical solution.

[0121] It should be noted that there is no specific order in which the calculation of the first and second limiting torques must be performed. The two can be performed in parallel and can be performed simultaneously or one after the other. The calculation of the first or second limiting torque can occur first. The order in which the first and second limiting torques are calculated is not intended to limit the order of the steps.

[0122] While calculating the first and second limiting torques and minimizing their output, the coolant pump gear is also adjusted in real time according to the changes in the three-electric operating parameters, including the following steps:

[0123] Obtain the VCU requested torque, power module junction temperature, power module NTC temperature, motor temperature, water inlet temperature, and the required water pump gear position.

[0124] Specifically in this embodiment, when the VCU requested torque ≠ 0 Nm, the water pump gear uses L2 gear, that is, the flow rate is 8 L / min. When the VCU requested torque is equal to 0 Nm, the water pump gear uses L2 gear for the first 10 seconds, that is, the flow rate is 8 L / min; after 10 seconds, the water pump gear uses L1 gear, that is, the flow rate is 3 L / min, as shown in the following table:

[0125]

[0126] The relationship between the power module junction temperature range and the water pump gear is as follows:

[0127]

[0128] The relationship between the power module NTC temperature range and the water pump gear is as follows:

[0129]

[0130] The relationship between the motor temperature level range and the water pump gear is as follows:

[0131]

[0132] The relationship between the water inlet temperature range and the water pump gear is as follows:

[0133]

[0134] It should be noted that the vehicle type targeted by this embodiment is a compact vehicle, including a compact sedan and a compact SUV. When faced with other different vehicle types such as mid-sized vehicles and medium-to-large vehicles, the relationship between the level intervals of the above-mentioned various physical quantities and the water pump gear position can be adaptively adjusted by those skilled in the art according to the actual vehicle type during debugging and calibration. The adjustment method is a prior art known in the art and is not limited here. Those skilled in the art should be aware that the relationship between the level intervals of the various physical quantities and the water pump gear position in this table is only a preferred method specific to this embodiment, and is not a limitation of the technical solution.

[0135] As can be seen, the VCU requested torque, power module junction temperature, power module NTC temperature, motor temperature, and water inlet temperature each have a gear threshold. Therefore, each gear threshold for each physical quantity has a hysteresis coefficient. During vehicle operation, the vehicle shifts to the next gear after each operating parameter rises and reaches the corresponding gear threshold. Since each operating parameter changes in real time, the VCU requested torque, power module junction temperature, power module NTC temperature, motor temperature, and water inlet temperature may all decrease. Once they drop to the gear threshold, the vehicle shifts back to the previous gear. If the operating parameters fluctuate around the gear threshold, gear jitter will occur. This will cause the water pump gear to jump continuously. In this embodiment, hysteresis coefficients are set for the gear thresholds for the VCU requested torque, power module junction temperature, power module NTC temperature, motor temperature, and water inlet temperature. This ensures that the gear thresholds reach different values ​​when rising and falling. The system can only return to the previous gear if the actual value of the gear threshold reached during falling is less than the actual value of the gear threshold reached during rising. This prevents gear hopping caused by fluctuations in physical quantities near the gear thresholds, maintains a stable gear position, and prevents gear hopping.

[0136] After obtaining the required water pump gears for each, take the maximum value.

[0137] The driver's required torque is determined based on the current motor speed and the current accelerator pedal opening. The driver's required torque is the product of the accelerator pedal opening and the maximum torque limit. The maximum torque limit is obtained by looking up the motor speed. Specifically in this embodiment, the relationship between the motor speed and the maximum torque limit is as follows:

[0138] Motor speed 1000r / min 2000r / min 3000r / min 4000r / min 5000r / min ……… 16000r / min Maximum torque limit 360Nm 360Nm 360Nm 360Nm 360Nm ……… 40Nm

[0139] It should also be noted that this embodiment targets compact vehicles, including compact sedans and compact SUVs. When dealing with other vehicle types, such as mid-sized and mid-to-large vehicles, the maximum torque limit can be adaptively adjusted by those skilled in the art during commissioning and calibration based on the actual vehicle model. The specific adjustment methods are well known in the art and are not limited here. Those skilled in the art should be aware that the maximum torque limits in this table are merely preferred methods specific to this embodiment and do not limit the technical solution.

[0140] If the driver's requested torque is greater than or equal to the second limit torque, the water pump gear adjustment value is set to 1, and the timer starts. Otherwise, the water pump gear adjustment value is set to 0. If the timer exceeds the preset time, the water pump gear adjustment value is set to 2. In this embodiment, the preset time is 20 seconds. In other embodiments, the preset time can be flexibly selected by those skilled in the art during calibration and adjustment based on specific needs. This is not limited here. Similarly, to prevent fluctuations in the water pump gear, a hysteresis coefficient is also set for the torque limiter.

[0141] By comparing the driver's required torque and the second limited torque, it is evaluated whether insufficient coolant flow causes the torque limit of the motor controller, and the water pump gear is increased to reduce the torque limit, thereby achieving automatic adjustment.

[0142] In this embodiment, the hysteresis coefficients set for various physical quantities and parameters can be flexibly set by those skilled in the art according to conditions such as vehicle type, motor model, battery capacity, etc.

[0143] The sum of the maximum value and the adjustment value is used as the output water pump gear. Specifically in this embodiment, the maximum limit of the water pump gear is L4, that is, 16L / min.

[0144] After the sum of the maximum value and the adjustment value is used as the output water pump gear, it is determined whether the opening of the accelerator pedal is greater than the second preset opening. The opening of the accelerator pedal is an important basis for judging the driver's intention. Specifically in this embodiment, the second preset opening is 80% of the maximum opening of the accelerator pedal. In other embodiments, the second preset opening can be flexibly set by those skilled in the art during calibration and adjustment, and is not limited here. If the opening is greater than the second preset opening, the lower limit of the water pump gear is set to 3, otherwise the water pump gear remains unchanged. There is a certain delay from the driver pressing the accelerator pedal to the VCU outputting the requested torque. The technical solution provided in this embodiment can control the water pump level in advance to avoid the risk of overheating caused by untimely cooling, and also avoid high-power operation of the water pump when high-power cooling is not required, thereby saving energy consumption.

[0145] The technical solution provided in this embodiment can dynamically evaluate the current required water pump level based on the three-electric operating parameters, realize autonomous control of the water pump level, improve the response speed of the cooling flow, and is more refined than the thermal management evaluation of the entire vehicle. On the premise of meeting the heat dissipation requirements, it can achieve low-power operation of the water pump as much as possible, saving energy consumption.

[0146] Similarly, to prevent the water pump gear from jumping, a hysteresis coefficient is set for the second preset opening. The setting of the hysteresis coefficient can also be flexibly set by those skilled in the art according to conditions such as vehicle model, motor model, battery capacity, etc.

[0147] In this embodiment, the junction temperature of the power module also plays a role in regulating the coolant pump, specifically as follows: the junction temperature level range of the power module junction temperature corresponding to the coolant flow is as follows. The relationship between the junction temperature level range and the water pump gear is as follows:

[0148] Junction temperature (℃) Water pump gear ≤70℃ 3L / min 70℃＜T≤110℃ 8L / min 110℃＜T≤135℃ 12L / min 135℃＜T 16L / min

[0149] It should also be noted that the vehicle models targeted by this implementation are compact vehicles, including compact sedans and compact SUVs. When faced with other different vehicle models such as mid-sized vehicles and medium-to-large vehicles, the relationship between the junction temperature limit and the IBGT switching frequency, as well as the relationship between the junction temperature level range and the water pump gear position, can be adaptively adjusted by those skilled in the art during debugging and calibration based on the actual vehicle model. The specific adjustment methods are well-known existing technologies in the art and are not limited here. Those skilled in the art should be aware that the maximum torque limit values ​​in this table are only preferred methods specific to this embodiment and do not limit the technical solution.

[0150] If the water pump gear corresponding to the current junction temperature range is lower than the output water pump gear, the current output water pump gear is maintained. If the water pump gear corresponding to the current junction temperature range is higher than the output water pump gear, the water pump gear corresponding to the current junction temperature range is used as the output water pump gear. Using the water pump gear corresponding to the current junction temperature range as the output water pump gear allows for dynamic estimation of the power module junction temperature, providing more effective protection against excessive junction temperatures, improving the junction temperature torque limit, and fully utilizing the hardware's current capability. After calculating the first limiting torque, the vehicle's water pump gear is proactively adjusted and increased to lower the junction temperature, avoiding junction temperature torque limitation and further improving hardware safety. If the output water pump gear is a junction temperature-adjusted water pump gear, the first and second limiting torques are recalculated based on the adjusted water pump gear, making the limiting more accurate and forming a closed-loop control method.

[0151] The technical solution provided by this embodiment calculates the junction temperature of the power module in real time according to the operation status of the entire vehicle in a closed-loop manner, and calculates the output torque based on it. At the same time, it compares the torque with the current limit. The comparison of the two outputs can avoid vehicle jerking caused by excessive output torque and the resulting heat accumulation, and can also avoid insufficient power caused by small output torque and the resulting waste of heat dissipation energy.

[0152] At the same time, this embodiment also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above-mentioned point cloud semantic segmentation method.

[0153] It will be understood by those skilled in the art that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program. Accordingly, the computer program can be stored in a non-volatile computer-readable storage medium, and the computer program can implement the method of any of the above-mentioned embodiments when executed. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0154] Furthermore, this embodiment further provides a motor vehicle having a motor and a motor controller, wherein the motor controller outputs torque to the motor through the aforementioned torque control method.

[0155] or the motor vehicle has the aforementioned computer equipment;

[0156] Or the motor vehicle has the aforementioned computer-readable storage medium, and the aforementioned torque control method is implemented when the computer program is executed by a processor.

[0157] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A torque control method, characterized in that: The torque control method comprises the following steps: The motor controller calculates the power module junction temperature based on the three-electric operation parameters and the water pump gear position, and calculates the first limit torque based on the power module junction temperature. The three-electric operation parameters include the coolant flow rate. The coolant flow rate has several threshold values, and the water pump gear position is divided by the coolant flow rate threshold value. The motor controller obtains the current limit value according to the three-electric operation parameters and the water pump gear position, and calculates the second limited torque according to the current limit value; The smaller value of the first limiting torque and the second limiting torque is used as the output torque; The motor controller calculates the power module junction temperature according to the three-electric operation parameters and the water pump gear position, and calculates the first limiting torque according to the power module junction temperature, including the following steps: Critical junction temperature calculation: Calculates the power module junction temperature corresponding to each critical coolant flow rate based on the three-electric operating parameters, including the IGBT switching frequency and motor speed. Junction temperature calculation: Calculate the power module junction temperature corresponding to the current coolant flow rate based on the current coolant flow rate, the coolant flow rate cutoff value corresponding to the current water pump gear position, and the power module junction temperature corresponding to the cutoff value; Adjustment: Obtain the first limit torque according to the motor speed and the power module junction temperature corresponding to the current coolant flow rate.

2. The torque control method according to claim 1, characterized in that: The power module junction temperature corresponding to the current coolant flow rate is calculated using the following formula: Tj=Tj n +(Tj n+1 -Tj n ) / (L n+1 -L n )*(LL n ) Among them, Tj is the power module junction temperature corresponding to the current coolant flow, n is the current water pump gear and the corresponding gear demarcation value sequence number, Tj n is the power module junction temperature corresponding to the coolant flow rate cutoff value, L is the current coolant flow rate, and Ln is the coolant flow rate cutoff value.

3. The torque control method according to claim 2, characterized in that: Calculating the power module junction temperature corresponding to each coolant flow cutoff value includes the following steps: Calculate the conduction loss of the IGBT chip for each bridge arm according to the following formula: Among them, P cond,IGBT is the conduction loss of the IGBT chip, t is the time, T0 is the working cycle of the chip, τ(t) is the duty cycle of the IGBT chip, V ce (t) is the voltage between the collector and emitter of the IGBT, V ce0 IGBT output characteristic curve I c =f(V ce ) The tangent line of the linear segment is extended to V ce The value at the intersection, r ce IGBT output characteristic curve I c =f(V ce ) is the slope of the tangent line of the linear segment, I m is the current amplitude, ω is the angular velocity, m is the modulation ratio, is the phase angle; Calculate the switching loss of the IGBT chip for each bridge arm according to the following formula: Among them, P SW,IGBT is the switching loss of the IGBT chip, f sw is the switching frequency, E on (I nom ,V nom ) is the typical operating condition opening loss, E off (I nom ,V nom ) is the typical operating condition turn-off loss, V dc is the battery voltage; Calculate the junction temperature of the IGBT chip for each bridge arm according to the following formula: Among them, Tj IGBT is the junction temperature of the IGBT chip, P IGBT is the total loss of the IGBT chip, R th,IGBT is the thermal resistance from IGBT chip to coolant, T w is the coolant temperature; Calculate the conduction loss of the diode chip for each bridge arm according to the following formula: Among them, P cond,Diode is the conduction loss of the diode chip, t is the time, T0 is the working cycle of the chip, τ'(t) is the duty cycle of the diode chip, V F (t) is the forward voltage of the diode, V F0 The diode characteristic curve I F =f(V F ) The tangent line of the linear segment is extended to V F The value at the intersection, r F The diode characteristic curve I F =f(V F ) is the slope of the tangent line of the linear segment, I m is the current amplitude, ω is the angular velocity, m is the modulation ratio, is the phase angle; Calculate the switching loss of the diode chip for each bridge arm according to the following formula: Among them, P sw,Diode is the switching loss of the diode chip, f sw is the switching frequency, E on (I nom ,V nom ) is the typical operating condition opening loss, E off (I nom ,V nom ) is the typical operating condition turn-off loss, V dc is the battery voltage; Calculate the junction temperature of the diode chip for each bridge arm according to the following formula: Among them, Tj DIode is the junction temperature of the diode chip, P Diode is the total loss of the diode chip, R th,IGBT is the thermal resistance from the diode chip to the coolant, T w is the coolant temperature; The larger value of the junction temperature of the IGBT chip and the junction temperature of the diode chip in each bridge arm is taken as the junction temperature of the bridge arm; Among the junction temperatures of all bridge arms, the maximum junction temperature is taken as the junction temperature of the power module.

4. The torque control method according to any one of claims 1 to 3, characterized in that: After calculating the first limiting torque according to the power module junction temperature, it is determined whether the power module junction temperature corresponding to the current coolant flow exceeds the junction temperature limit, and the amplitude of reducing the switching frequency is selected according to the exceeded junction temperature limit.

5. The torque control method according to any one of claims 1 to 3, characterized in that: The motor controller obtains the current limit value according to the three-electric operation parameters, and calculates the second limited torque according to the current limit value, including the following steps: Initial setting: Get the current initial output current limit value based on the three-electric operation parameters and the water pump gear position; Determination: The three-electric operation parameters include the opening of the accelerator pedal. Whether the current initial output current limit needs to be limited is determined based on the opening of the accelerator pedal. When the opening of the accelerator pedal is greater than or equal to a first preset opening, the current initial output current limit is adopted. When the opening of the accelerator pedal is less than the first preset opening, the current initial output current limit is reduced to form a process output current limit. Limitation: The second limiting torque is determined based on the current motor speed and the initial output current limit or the process output current limit.

6. The torque control method according to claim 5, characterized in that: The torque control method further includes a thermal management system controlling a coolant pump gear position according to three-electric operation parameters, including: The three electric operating parameters include VCU requested torque, power module NTC temperature, motor temperature, and water inlet temperature. Obtain the VCU requested torque, power module NTC temperature, motor temperature, water inlet temperature, power module junction temperature, and the required water pump gear position, and take the maximum value among them. Determining a driver's required torque based on the motor speed and the accelerator pedal opening, where the driver's required torque is the product of the accelerator pedal opening and a maximum torque limit, where the maximum torque limit is obtained from the motor speed, and determining an adjustment value for the coolant water pump gear based on the required torque; The sum of the maximum value and the adjustment value is used as the output pump gear.

7. The torque control method according to claim 6, characterized in that: If the driver's required torque is greater than or equal to the second limit torque, the adjustment value of the water pump gear is 1 and the timing is started at the same time. Otherwise, the adjustment value of the water pump gear is 0. If the timing time is greater than the preset time, the adjustment value of the water pump gear is 2.

8. The torque control method according to claim 6, characterized in that: After the sum of the maximum value and the adjustment value is used as the output water pump gear, it is determined whether the opening of the accelerator pedal is greater than the second preset opening. If it is, the lower limit value of the water pump gear is set to 3, otherwise the water pump gear remains unchanged.

9. The torque control method according to claim 6, characterized in that: Determine the junction temperature level range of the power module junction temperature corresponding to the coolant flow rate. If the water pump gear corresponding to the junction temperature level range is lower than the output water pump gear, maintain the current output water pump gear. If the water pump gear corresponding to the junction temperature level range is higher than the output water pump gear, use the water pump gear corresponding to the junction temperature level range as the output water pump gear.

10. The torque control method according to claim 9, characterized in that: If the water pump gear corresponding to the junction temperature level range is used as the output water pump gear, the first limiting torque and the second limiting torque are recalculated according to the adjusted water pump gear.

11. The torque control method according to claim 8, characterized in that: The VCU requested torque, power module junction temperature, power module NTC temperature, motor temperature and water inlet temperature are respectively provided with gear boundary values, and the gear boundary value, the boundary value of the coolant flow rate, the first preset opening, the second preset opening and the second limiting torque are respectively provided with hysteresis coefficients.

12. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the torque control method according to any one of claims 1 to 11 is implemented.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the torque control method according to any one of claims 1 to 11 is implemented.

14. A motor vehicle, characterized in that: The motor vehicle comprises a motor and a motor controller, wherein the motor controller outputs torque to the motor using the torque control method according to any one of claims 1 to 11; or the motor vehicle has the computer device according to claim 12; Or the motor vehicle has the computer-readable storage medium according to claim 13, and when the computer program is executed by a processor, the torque control method according to any one of claims 1 to 11 is implemented.

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