Three-in-one power assembly, coaxial reducer, active lubrication structure and control algorithm

Abstract

This invention discloses a three-in-one powertrain, a coaxial reducer, an active lubrication structure, and a control algorithm. The active lubrication structure includes an oil pan, an electronic oil pump, a main oil passage in the coaxial reducer, a lubrication nozzle assembly, and a return oil passage. The three-in-one powertrain includes a drive motor, a coaxial reducer, a motor controller, and an oil cooler. The three-in-one powertrain also features a thermal management control system, which includes an oil-cooled internal circulation subsystem and a water-cooled external circulation subsystem. The two subsystems exchange heat through the oil cooler. This invention addresses a series of pain points in the new energy vehicle powertrain field, such as poor lubrication, poor dynamic balance, low motor control precision, and poor thermal management efficiency, significantly improving the overall performance of the three-in-one powertrain.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicle powertrain technology, specifically involving a three-in-one powertrain, a coaxial reducer, an active lubrication structure, and a control algorithm. Background Technology

[0002] The powertrain of new energy vehicles is showing a trend towards high integration and coaxiality. The three-in-one powertrain (drive motor + coaxial reducer + motor controller) has become the mainstream solution due to its high space utilization and superior transmission efficiency. International companies such as Schaeffler and ZF have already mass-produced planetary coaxial reducers. However, existing technologies still have many key pain points: 1. Defects in lubrication method: Existing coaxial reducers generally use splash lubrication, which relies on the rotation of gears to throw oil to the lubrication parts. Under low speed / specific working conditions, lubrication is easily insufficient. At high speed, the oil is stirred up, generating a lot of heat and power loss. The lubrication effect is random. Moreover, oil film rupture and tooth surface scuffing are prone to occur when the high speed load is concentrated and the low speed is heavy load. 2. Prominent dynamic balance problem: Traditional coaxial reducers integrate the planetary gear transmission with the differential housing on the same axis. The differential has 2 or 4 bevel planetary gears. With an odd number of planetary gears, it is impossible to achieve a uniform distribution of circumferential mass, resulting in large eccentric mass and causing serious dynamic balance problems. 3. Low motor control precision: Traditional MTPA / MTPV control algorithms have slow dynamic response speed and low control precision, which cannot meet the control requirements of high-speed and high-torque motors; 4. Poor thermal management efficiency: The cooling system of traditional three-in-one powertrains is mostly a single-cycle design, with lubrication and cooling operating independently. This results in low heat utilization efficiency, insufficient waste heat recovery capacity, and a lack of intelligent control for switching between heat dissipation and heating modes, leading to high overall vehicle energy consumption. Summary of the Invention

[0003] The main objective of this invention is to provide a three-in-one powertrain, coaxial reducer, active lubrication structure and control algorithm to solve a series of pain points in the field of new energy vehicle powertrains, such as poor lubrication effect, poor dynamic balance, low motor control precision and poor thermal management efficiency, and to significantly improve the overall performance of the three-in-one powertrain.

[0004] To achieve the above objectives, the present invention provides an active lubrication structure, including an oil pan, an electronic oil pump, a coaxial reducer main oil passage, a lubrication nozzle assembly, and a return oil passage, wherein: The oil pan is used to store lubricating oil. The electronic oil pump is integrated inside the three-in-one powertrain. The oil inlet of the electronic oil pump is connected to the oil pan and the oil outlet is sealed to the main oil passage of the coaxial reducer. The lubrication nozzle assembly includes a first nozzle and a second nozzle disposed on the housing of the coaxial reducer, and a third nozzle and a fourth nozzle disposed on the housing connecting the drive motor and the coaxial reducer. Each nozzle is connected to the main oil passage of the coaxial reducer. The first nozzle is positioned towards the meshing point of the double planetary pinion and the internal gear ring, the third nozzle is positioned towards the meshing area of ​​the double planetary gear and the sun gear, and the second nozzle and the fourth nozzle are positioned towards the front and rear oil collection caps, respectively. The oil return circuit includes multiple oil outlets located under the housing where the drive motor and the coaxial reducer are connected. The oil outlets are connected to the oil pan through the oil return channel between the motor housing and the coaxial reducer housing, forming a closed-loop lubrication circuit.

[0005] The present invention also provides a coaxial reducer, characterized in that it includes the active lubrication structure as described in claim 1, and further includes an integrated NW planetary gear reducer, a differential assembly, and a coaxial reducer housing, wherein: The NW planetary gear reducer includes three tower-type planetary gear assemblies, an internal gear ring, a sun gear, and two front and rear oil collection covers. The oil collection covers have cover holes for collecting oil sprayed from the nozzles and splashed from the gears and flowing into the pins. The tower-type planetary gear assembly consists of tower-type planetary gears, pins, needle roller bearings, and spacers. Each of the three pins throws oil out through two through holes in its inner wall to lubricate the needle roller bearings. The differential assembly includes a differential housing, three bevel-tooth planetary gears and ball bearings, two bevel-tooth half-shaft gears and flat bearings, a coiled pin, a planetary shaft, and a cage. The planetary shaft passes through the inner bore of the bevel-tooth planetary gears and is fixed to the planetary carrier by the coiled pin. Its inner wall has two through holes for throwing out oil to lubricate the inner bore of the planetary gears, the meshing area of ​​the gear teeth, and the ball bearings. The cage is installed at the intersection of the planetary shafts and has three through holes evenly distributed on its side wall for fixing the planetary shafts and achieving precise positioning.

[0006] This invention also provides an active lubrication control algorithm, comprising the following steps: Step S1: Perform parametric modeling and temperature node division on the NW planetary gear reducer and differential assembly, and construct steady-state and transient heat flow balance equations; Step S2: Couple the heat flow balance equation with the thermal network model of the relevant components of the vehicle's three-in-one powertrain, and collect or estimate operating parameters in real time, including motor speed, torque, coaxial reducer oil temperature, oil pressure, gear meshing load, and ambient temperature. Step S3: Based on the coupled thermal network model and combined with the elastohydrodynamic lubrication theory, the minimum oil film thickness of the meshing surface of the bevel planetary gears of the tower planetary gear assembly, internal gear ring, sun gear and differential assembly is predicted in real time, and dynamic calibration is performed through the temperature correction coefficient. Step S4: Determine whether the predicted minimum oil film thickness has reached the preset threshold. If not, dynamically adjust the speed of the electronic oil pump and control the oil injection quantity and oil pressure of the first nozzle, second nozzle, third nozzle, fourth nozzle, and subsequent additional nozzles without limitation in number and position, until the oil film thickness reaches the preset threshold, ensuring that the meshing area of ​​the coaxial reducer gear and the meshing surface of the bevel planetary gear always maintain the best lubrication state. Step S5: Identify the operating conditions of climbing, descending, rapid acceleration, emergency braking, and cornering using the vehicle operating condition identification module. Based on the identification results, optimize the oil injection distribution strategy of each nozzle to ensure that the lubricating oil accurately reaches the target lubrication points.

[0007] The present invention also provides a three-in-one powertrain, including a drive motor, a coaxial reducer as described in claim 2, a motor controller, and an oil cooler. The three-in-one powertrain further includes a thermal management control system, which comprises an oil-cooled internal circulation subsystem and a water-cooled external circulation subsystem. The two subsystems exchange heat through the oil cooler, wherein: The oil-cooled internal circulation subsystem consists of a drive motor, a coaxial reducer, an oil cooler, and an adjustable speed oil pump. It shares the lubrication circuit with the active lubrication structure, and the lubricating oil simultaneously undertakes the functions of lubrication and internal cooling. The water-cooled external circulation subsystem consists of a motor controller, a drive motor, a coaxial reducer, an oil cooler, a low-temperature radiator, a water pump, and a passenger compartment heating air box. Cooling water flows sequentially through the motor controller, the oil cooler, the drive motor housing, and the coaxial reducer housing to achieve external cooling and waste heat recovery.

[0008] As a further preferred technical solution to the above technical solution, the thermal management control system has three operating modes: heat dissipation mode, waste heat recovery mode, and heat preservation mode, wherein: Heat dissipation mode: When there is no heating requirement in the passenger compartment, and the temperature of the motor, electronic control, coaxial reducer, water temperature, or oil temperature reaches the first warning threshold, the low-temperature radiator is turned on, the blower of the heater box is turned off, and the cooling water dissipates heat to the outside environment through the low-temperature radiator. Insulation mode: When the passenger compartment has a heating requirement, and the temperature of the motor, electronic control, coaxial reducer, water temperature, or oil temperature has not reached the first warning threshold, the residual heat meets the heating requirement of the passenger compartment, and the water temperature has not reached the second warning threshold, the low-temperature radiator and blower are disconnected, and the cooling water circulates to absorb the heat of the three-in-one powertrain to achieve insulation. Waste heat recovery mode: When the crew cabin has a heating demand, the waste heat does not meet the crew cabin heating demand, and the water temperature reaches the second warning threshold, the low temperature radiator is disconnected and the blower is turned on. The cooling water will transfer the absorbed heat to the crew cabin heating air box to achieve crew cabin heating.

[0009] As a further preferred technical solution of the above technical solution, the thermal management control system is equipped with a waste heat heating control algorithm. In the waste heat recovery mode, the MTPA control point of the drive motor is switched from point a to point b, keeping the drive torque unchanged, increasing the phase current of the drive motor, and increasing the losses of the motor and the electronic control to generate more heat; point a is the operating point of drive torque T1 and actual phase current ia_ref, and point b is the operating point of the same drive torque T1 and actual phase current ib_ref, and ib_ref ​​is greater than ia_ref; The transfer speed and position from point A to point B are set according to the heating demand of the crew cabin; when the heating demand is high, the transfer rate is high and the phase current at point B is higher than that at point A; when the heating demand is low, the transfer rate is low and the phase current at point B is lower than that at point A.

[0010] As a further preferred technical solution to the above technical solution, the drive motor is controlled using the sliding mode model predictive control (SMMPC) algorithm to improve the dynamic response speed and control accuracy of the motor control. The control process of the SMMPC algorithm includes: The torque command issued by the vehicle controller (VCU) is converted into the command current in the dq coordinate system, and the current limit circle and voltage limit circle are calculated in combination with the real-time parameters of the motor. The motor voltage equation in the dq coordinate system is discretized based on the first-order Euler discretization method to obtain the motor stator current prediction equation at time k+1. Construct d-axis and q-axis control sliding surfaces, and calculate d-axis and q-axis command voltages using exponential approach rates; The command voltage in the dq rotating coordinate system is converted into the voltage in the α and β stationary coordinate systems. Based on the voltage space vector pulse width modulation algorithm (SVPWM), six PWM signals are generated to drive the power devices of the motor controller to control the drive motor.

[0011] The beneficial effects of this invention are as follows: 1. Significantly improved lubrication performance: The active lubrication structure adopts a directional precision injection design, combined with an intelligent control algorithm based on a thermal network model, to achieve real-time prediction of oil film thickness and dynamic adjustment of lubrication parameters. This solves the problems of uneven splash lubrication, insufficient lubrication at low speeds, and high oil loss at high speeds caused by traditional splash lubrication. It effectively prevents tooth surface scuffing and lubrication failure, improving the transmission efficiency and service life of the reducer. At the same time, the dynamic balance optimization design of the coaxial reducer completely solves the dynamic balance problem caused by eccentric mass, reducing vibration and noise during high-speed operation.

[0012] 2. High thermal management efficiency and low energy consumption: The dual-circulation system of oil cooling and water cooling achieves coordinated operation of lubrication and cooling, resulting in high heat exchange efficiency; the intelligent switching of three working modes makes full use of the waste heat of the powertrain to heat the passenger compartment without the need for additional power consumption, which significantly reduces the energy consumption of the whole vehicle and improves the driving range of new energy vehicles; the waste heat heating control algorithm can dynamically adjust the motor loss according to the heating demand, further improving the heating efficiency.

[0013] 3. Excellent motor control accuracy and response speed: The Smooth Mode Model Predictive Control (SMMPC) algorithm combines the robustness of sliding mode control with the accuracy of model predictive control, effectively making up for the shortcomings of traditional MTPA / MTPV control, improving the control accuracy and dynamic response speed of the drive motor, and adapting to the operating requirements of high-speed and high-torque motors.

[0014] 4. Compact structure and high integration: The active lubrication structure and thermal management system share the lubrication oil circuit, and the coaxial reducer adopts an integrated structural design. The components of the entire three-in-one powertrain are highly integrated, with high space utilization, which meets the requirements of new energy vehicles for powertrain miniaturization and lightweighting. Attached Figure Description

[0015] Figure 1 This is a control block diagram of the SMMPC (Sliding Mode Model Predictive Control) algorithm for the drive motor of the present invention. Figure 2 This is a structural diagram of the drive circuit of the motor controller of the present invention; Figure 3 This is the voltage space vector diagram of the voltage space vector modulation algorithm SVPWM of this invention; Figure 4 This is a schematic diagram of the MTPA control operating point switching in the waste heat recovery mode of the three-in-one powertrain of the present invention. Figure 5 This is a schematic diagram of the structure of the three-in-one powertrain oil-cooled and water-cooled dual-circulation system of the present invention; Figure 6 This is a flowchart illustrating the working mode control of the three-in-one powertrain thermal management system of the present invention. Figure 7 This is a schematic diagram showing the main components and functions of the three-in-one powertrain of the present invention; Figure 8 This is a schematic diagram of the interface of the motor controller and the cooling water flow direction of the present invention; Figure 9 This is a schematic diagram of the internal structure and oil pan arrangement of the three-in-one powertrain of the present invention; Figure 10A This is a schematic diagram of the NW two-stage planetary gear transmission in the coaxial reducer of the present invention; Figure 10B This is a schematic diagram of the NW two-stage planetary gear transmission in the coaxial reducer of the present invention; Figure 11 This is a schematic diagram showing the arrangement of nozzles 1 and 2 in the power output housing of the coaxial reducer of the present invention. Figure 12 This is a schematic diagram showing the arrangement of nozzles 3 and 4 in the housing connecting the drive motor and the reducer of the present invention. Figure 13A This is a schematic diagram of the overall structure of the coaxial reducer of the present invention; Figure 13B This is a schematic diagram of the overall structure of the coaxial reducer of the present invention; Figure 14 This is a schematic diagram showing the arrangement of the oil outlet of the drive motor and reducer connection housing of the present invention. Detailed Implementation

[0016] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0017] In the preferred embodiments of the present invention, those skilled in the art should note that the drive motors and the like involved in the present invention can be considered as prior art.

[0018] Preferred embodiment.

[0019] This invention discloses an active lubrication structure, including an oil pan, an electronic oil pump, a coaxial reducer main oil passage, a lubrication nozzle assembly, and a return oil passage, wherein: like Figure 9 As shown, the oil pan is used to store lubricating oil, the electronic oil pump is integrated inside the three-in-one powertrain, the oil inlet of the electronic oil pump is connected to the oil pan and the oil outlet is sealed to the main oil passage of the coaxial reducer. like Figures 11-12 As shown, the lubrication nozzle assembly includes a first nozzle (i.e., nozzle 1) and a second nozzle (i.e., nozzle 2) disposed on the housing of the coaxial reducer (power output), and a third nozzle (i.e., nozzle 3) and a fourth nozzle (i.e., nozzle 4) disposed on the housing connecting the drive motor and the coaxial reducer. Each nozzle is connected to the main oil passage of the coaxial reducer. The first nozzle is positioned towards the meshing point of the double planetary pinion and the internal gear ring, the third nozzle is positioned towards the meshing area of ​​the double planetary gear and the sun gear, and the second and fourth nozzles are positioned towards the front and rear oil collection covers, respectively. (There is no limitation on the number of nozzles, nozzle diameter, and nozzle position at the interface between the coaxial reducer and the motor housing, and it can be used for all parts inside the coaxial reducer.) like Figure 14As shown, the oil return circuit includes multiple (preferably 3) oil outlets (also referred to as oil return ports relative to the motor) located under the housing connecting the drive motor and the coaxial reducer. The oil outlets are connected to the oil pan through the oil return channel between the motor housing and the coaxial reducer housing, forming a closed-loop lubrication circuit.

[0020] Specifically, as shown in Figures 10-13, this invention also discloses a coaxial reducer, including an active lubrication structure, and further including an integrated NW planetary gear reducer, a differential assembly, and a coaxial reducer housing (which is the same component as the planet carrier of the NW planetary gear reducer, connected to the outer side of the internal gear ring of the NW planetary gear reducer, and internally houses the NW planetary gear reducer and the differential assembly), wherein: The reducer includes an integrated NW planetary gear reducer, a differential assembly, and a reducer housing (which is the same component as the planet carrier of the NW planetary gear reducer, connects to the outer side of the internal gear ring of the NW planetary gear reducer, and houses the NW planetary gear reducer and the differential assembly), wherein: The NW planetary gear reducer includes three tower-type planetary gear assemblies, an internal gear ring, a sun gear, and two oil collection covers (front and rear). Each oil collection cover has a cap hole for collecting oil sprayed from the nozzle and splashed from the gears, which then flows into the pins. Each tower-type planetary gear assembly consists of tower-type planetary gears, pins, needle roller bearings, and spacers. Each of the three pins discharges oil through two through holes in its inner wall to lubricate the needle roller bearings. (The three tower-type planetary gear assemblies consist of tower-type planetary gears, pins, needle roller bearings, and spacers. The tower-type planetary gears have a double-gear structure; the large gear meshes with the rotor shaft (sun gear), and the small gear meshes with a fixed...) The internal gear ring of the reducer meshes, rotating on its own axis while revolving around a central axis, achieving two-stage transmission; the pin shaft: uses riveting to achieve integrated revolution with the planetary carrier, throwing the collected oil through the inner wall through-hole to lubricate the needle rollers and raceways in the needle roller bearing; the needle roller bearing: located between the inner bore of the planetary gear and the planetary gear shaft, responsible for bearing load and allowing the planetary gear to rotate flexibly. Spacer ring: isolates the two needle roller bearings on both sides of the tower-type planetary gear, ensuring axial distance to prevent cross-flow while maintaining rotational balance. Oil collection cap: the NW planetary gear reducer has two oil collection caps (front and rear) to collect oil sprayed from the nozzles and splashed from the gears, flowing into the pin shaft through the cap holes. The differential assembly includes a differential housing, three bevel-tooth planetary gears and ball bearings, two bevel-tooth half-shaft gears and flat bearings, a coiled pin, a planetary shaft, and a cage. The planetary shaft passes through the inner bore of the bevel-tooth planetary gears and is fixed to the planetary carrier by the coiled pin. Its inner wall has two through holes for throwing out oil to lubricate the inner bore of the planetary gears, the meshing area of ​​the gear teeth, and the ball bearings. The cage is installed at the intersection of the planetary shafts and has three through holes evenly distributed on its side wall for fixing the planetary shafts and achieving precise positioning.

[0021] This invention also discloses an active lubrication control algorithm, comprising the following steps: Step S1: Perform parametric modeling and temperature node partitioning on the NW planetary gear reducer and differential assembly, and construct steady-state and transient heat flow balance equations. The specific implementation is as follows: 1. Implementation methods of parametric modeling: Determine the core parameters: First, it is necessary to identify the key geometric and performance parameters of the NW planetary array as variables, which mainly include: 1) Basic parameters: number of teeth, module, pressure angle, helix angle, tooth width, and displacement coefficient of the sun gear, double-tower planetary gear, and ring gear.

[0022] 2) Structural parameters: structural dimensions of the planetary carrier, dimensions of the differential housing, positions of the needle roller bearings and angular contact ball bearings, dimensions of the oil seals, etc.

[0023] 3) Material properties: density, elastic modulus, Poisson's ratio, thermal conductivity, specific heat capacity.

[0024] 2. Temperature node division method: Constructing the thermal equilibrium equation requires discretizing the continuous physical system and using the thermal network method to simplify the complex structure into a network consisting of nodes and thermal resistance.

[0025] 1) Node settings a) Solid nodes: Sun gear node, two nodes for each planetary gear (including the large planetary gear and small planetary gear in a double-tower planetary gear system; these can be considered as two nodes), ring gear node, planet carrier node, differential housing node, left and right half-shaft gear nodes, inner and outer ring nodes of each bearing, input / output shaft nodes, etc.

[0026] b) Fluid nodes: key lubricating oil nodes such as the four oil injection ports, oil pan and oil return port in the coaxial reducer housing, lubricating oil nodes of the oil cooler, water cooling points of the oil cooler, and ambient air nodes.

[0027] 2) Thermal resistance setting: Establish thermal resistance between nodes to simulate the heat transfer path. The main thermal resistances include: a) Contact thermal resistance: between gear meshing surfaces, between the rolling elements and raceways of needle roller bearings, and between the rolling elements and raceways of angular contact ball bearings.

[0028] b) Conductive thermal resistance: The transfer of heat within a component or between components via interference fit surfaces.

[0029] c) Convective heat transfer resistance: Convective heat transfer between rotating parts such as gear end faces, tooth profile surfaces, and housings and lubricating oil, oil cooler water cooling, and ambient air.

[0030] d) Radiative thermal resistance: This is usually negligible when the temperature is not high, but it needs to be considered if the temperature difference is large or natural cooling occurs.

[0031] 3. Construct steady-state and transient thermal equilibrium equations: Based on the law of conservation of energy (Kirchhoff's laws), establish the heat balance equation for each node: a) Steady-state thermal equilibrium equation ; , :node and adjacent nodes temperature, For nodes and The total thermal resistance between them (a combination of conduction, convection, or contact thermal resistance). Apply to node Heat sources on the surface (such as gear meshing friction heat, bearing friction heat, oil churning loss, etc.).

[0032] b) Transient thermal equilibrium equation Transient analysis considers the heat capacity of the node itself, that is, the increase in the internal energy of the node per unit time is equal to the net inflow of heat; ; : It is a node heat capacity, It represents the quality of the region represented by the node. It is the specific heat capacity of the material; : is the rate of change of node temperature over time. A heat source that changes over time.

[0033] Step S2: Couple the heat flow balance equation with the thermal network model of the relevant components (motor, controller) of the vehicle three-in-one powertrain, and collect or estimate in real time a series of operating parameters of the three-in-one powertrain, including motor speed, torque, coaxial reducer oil temperature, oil pressure, gear meshing load and ambient temperature; Step S3: Based on the coupled thermal network model and combined with the elastohydrodynamic lubrication theory, the minimum oil film thickness at the meshing surfaces of the bevel planetary gears in the tower planetary gear assembly, internal gear ring, sun gear, and differential assembly is predicted in real time, and dynamically calibrated using a temperature correction coefficient, wherein: The implementation of real-time prediction of minimum oil film thickness is as follows: Real-time prediction of minimum oil film thickness based on a coupled thermal network model relies on establishing an iterative solution framework that couples thermal, fluid, and solid-state multiphysics fields. The prediction is achieved through a cyclical process of three steps: theoretical model calculation, temperature correction, and dynamic calibration.

[0034] 1: Isothermal film thickness calculation based on elastohydrodynamic lubrication theory; 2: Thermal network model output and temperature correction; 3: Dynamic calibration mechanism; Through the above three steps, the basic temperature data for calculating oil film thickness is obtained from the established coupled thermal network model. Then, through interaction and dynamic calibration with the elastohydrodynamic lubrication model, an accurate prediction system that can reflect the influence of thermal effects on lubrication status in real time is established. The specific implementation of dynamic calibration using a series of optimization methods, such as temperature correction coefficient, is as follows: The purpose of dynamic calibration is to correct the effect of temperature on oil film thickness calculation in real time, ensuring that the theoretical model matches the actual situation as closely as possible. Within the framework of coupling the thermal network model and elastohydrodynamic lubrication theory, dynamic calibration can be understood as an adaptive correction process based on temperature feedback.

[0035] Specific solution: Online calibration based on neural network AI big data model machine learning. For complex nonlinear relationships, a neural network is pre-trained, and the temperature and operating parameters output by the thermal network are used as inputs to directly output the calibrated oil film thickness.

[0036] 1) Training phase: Generate a large number of samples (temperature, load, rotation speed, measured film thickness) using experimental data or high-precision simulation (such as CFD + thermo-elastohydrodynamic coupling) for network training; 2) Online application: The node temperature and operating parameters output by the thermal network are sent into the neural network in real time to directly obtain the calibration film thickness.

[0037] Step S4: Determine whether the predicted minimum oil film thickness has reached the preset threshold. If not, dynamically adjust the speed of the electronic oil pump and control the oil injection quantity and oil pressure of the first nozzle, second nozzle, third nozzle, fourth nozzle, and subsequent additional nozzles without limitation in number and position, until the oil film thickness reaches the preset threshold, ensuring that the meshing area of ​​the coaxial reducer gear and the meshing surface of the bevel planetary gear always maintain the best lubrication state. Step S5: Identify driving conditions such as climbing, descending, rapid acceleration, sudden braking, and cornering using the vehicle operating condition recognition module. Based on the recognition results, optimize the fuel injection distribution strategy for each nozzle to ensure that the lubricating oil accurately reaches the target lubrication points. The specific implementation of the fuel injection distribution strategy is as follows: It can utilize the vehicle's existing sensors (IMU, vehicle speed, wheel speed, pedal travel, etc.) to identify various working conditions such as climbing, descending, rapid acceleration, emergency braking, and cornering. For example, in a cornering situation where the gear tilts to the right: lateral acceleration causes the lubricating oil to be thrown outwards from the corner, resulting in insufficient oil supply to the inner gears. Simultaneously, lubricating oil accumulates inside the differential between the planetary gears and half-shaft gears, increasing oil churning losses. Distribution strategy: appropriately increase the oil injection volume at [nozzle 3: the meshing surface of the sun gear and planetary gears]; appropriately increase the oil injection volume at [nozzle 4: directly spraying the oil collector to lubricate the pins and needle roller bearings]; appropriately decrease the oil injection volume at [nozzle 2: directly spraying the oil collector to lubricate the pins and needle roller bearings]; appropriately decrease the oil injection volume at [nozzle 1: lubricating the tower gear and gear ring meshing surface]; other operating conditions are similar.

[0038] like Figure 7 As shown, this invention also discloses a (vehicle-mounted) three-in-one powertrain, including a drive motor, a coaxial reducer, a motor controller, and an oil cooler. The coaxial reducer includes an active lubrication structure, such as... Figure 5 As shown, the three-in-one powertrain also includes a thermal management control system, which comprises an oil-cooled internal circulation subsystem and a water-cooled external circulation subsystem. The two subsystems exchange heat through an oil cooler. The oil-cooled internal circulation subsystem consists of a drive motor, a coaxial reducer, an oil cooler, and an adjustable speed oil pump. It shares the lubrication circuit with the active lubrication structure of the (vehicle-mounted three-in-one powertrain coaxial reducer), and the lubricating oil simultaneously undertakes the functions of lubrication and internal cooling. The water-cooled external circulation subsystem consists of a motor controller, a drive motor, a coaxial reducer, an oil cooler, a low-temperature radiator, a water pump, and a passenger compartment heating air box. Cooling water flows sequentially through the motor controller, the oil cooler, the drive motor housing, and the coaxial reducer housing to achieve external cooling and waste heat recovery. (The thermal management control system is equipped with temperature, oil pressure, and flow sensors, which can collect the temperature of each component, water temperature, and oil temperature in real time, and automatically switch between heat dissipation mode, heat preservation mode, and waste heat recovery mode according to the heating / cooling needs of the passenger compartment of the vehicle.)

[0039] The three-in-one powertrain integrates the drive motor, coaxial reducer, motor controller, and oil cooler into a single unit. This design not only boasts a compact structure and saves space but also reduces weight and improves efficiency. The structure and function of the main components are as follows: Drive motor: Internally oil-cooled, externally water-cooled; the motor housing has a cast spiral water channel, or, depending on design requirements, oil cooling can be used directly without the spiral water channel; the coolant flows through this channel, carrying away the heat generated by the stator core. Additionally, the motor shaft, oil slinger holes, and oil channels: the internal motor shaft is hollow, and the motor oil channels are connected to the oil cooler. The shaft surface has carefully designed oil spray holes, which, during high-speed rotation, utilize centrifugal force to precisely spray cooling oil onto the stator end windings and bearings, achieving direct and efficient cooling.

[0040] Motor controller: Located to the side of the motor and reducer, making full use of space. There are three external interfaces, such as...Figure 8 As shown: 1) High-voltage harness interface: A robust orange or black interface that connects to the high-voltage DC power from the battery.

[0041] 2) Low-voltage wiring harness interface: A smaller signal interface that connects the vehicle's communication network and sensors.

[0042] 3) Three-phase copper busbar interface: The internal structure is directly connected to the motor through a thick copper busbar to transmit variable frequency AC power.

[0043] Coaxial reducer: It converts the high speed and low torque of the motor into the low speed and high torque required by the wheels, thus realizing power output. Located on one side of the motor, the coaxial reducer housing is tightly integrated with the motor housing to form a single power output end. The meaning of "coaxial" is that the input shaft of the motor and the output shaft of the reducer are on the same axis. This layout makes the axial length of the assembly shorter, which is convenient for vehicle layout.

[0044] Oil cooler: This acts as the "heat exchanger" of the entire system, transferring waste heat carried away by the lubricating oil from high-temperature components to the external cooling circuit. The oil cooler is a multi-layered plate or tubular metal heat exchanger, typically compactly integrated above the motor housing. Water inlet: Connects to the vehicle's coolant circulation lines, allowing the coolant to flow through internal channels. Oil inlet: Connects to the inlet pipe from the motor's oil pan and the outlet pipe leading to the internal oil passages of the motor.

[0045] Lubrication and cooling of the three-in-one powertrain system: 1) The drive motor, motor controller, and coaxial reducer are externally cooled using an active water cooling system. Cooling water enters the controller through the inlet, then passes through the oil cooler, the drive motor and coaxial reducer housing, and finally connects to the water pump through the outlet. In heat dissipation mode, the cooling water passes through the low-temperature radiator; in heat preservation mode, the cooling water does not pass through the low-temperature radiator; in waste heat recovery mode, the cooling water does not pass through the low-temperature radiator but passes through the blower.

[0046] 2) The drive motor and coaxial reducer utilize an active oil cooling system. Cooling oil can directly enter the motor winding surface and permanent magnets, directly cooling localized hot spots without affecting motor performance, resulting in high cooling efficiency. Simultaneously, the coaxial reducer also employs an active oil cooling system. The cooling fluid in the oil cooling circuit uses a specific lubricating oil. After passing through the drive motor and coaxial reducer circuits, the lubricating oil absorbs heat, its temperature rises, and its viscosity decreases. Therefore, the high-temperature lubricating oil can both lubricate the transmission components inside the coaxial reducer and cool the heat-generating components. The oil cooling circuit exchanges heat with the water cooling circuit through an oil cooler. Typically, the temperature of the oil cooling circuit is significantly higher than that of the water cooling circuit, allowing heat to be transferred from the oil cooling circuit to the water cooling circuit, and then dissipated to the external environment or the vehicle's passenger compartment through the radiator in the water cooling circuit.

[0047] Specifically, such as Figure 6 As shown, the thermal management control system has three operating modes: heat dissipation mode, waste heat recovery mode, and heat preservation mode, wherein: Heat dissipation mode: When there is no heating requirement in the passenger compartment, and the temperature of the motor, electronic control, coaxial reducer, water temperature, or oil temperature reaches the first warning threshold (i.e., warning threshold 1), the low-temperature radiator is turned on, the blower of the heater box is turned off, and the cooling water dissipates heat to the outside environment through the low-temperature radiator. Insulation mode: When the passenger compartment has a heating requirement, and the temperature of the motor, electronic control, coaxial reducer, or water and oil temperature has not reached the first warning threshold, the residual heat meets the heating requirement of the passenger compartment, and the water temperature has not reached the second warning threshold (i.e., warning threshold 2), the low-temperature radiator and blower are disconnected, and the cooling water circulates to absorb the heat of the three-in-one powertrain to achieve insulation. Waste heat recovery mode: When the crew cabin has a heating demand, the waste heat does not meet the crew cabin heating demand, and the water temperature reaches the second warning threshold, the low temperature radiator is disconnected and the blower is turned on. The cooling water will transfer the absorbed heat to the crew cabin heating air box to achieve crew cabin heating.

[0048] More specifically, such as Figure 4 As shown, the thermal management control system is equipped with a waste heat heating control algorithm. In waste heat recovery mode, the MTPA control point of the drive motor switches from point a to point b, keeping the drive torque constant, increasing the phase current of the drive motor, and increasing the losses of the motor and electronic control to generate more heat. Point a is the operating point of drive torque T1 and actual phase current ia_ref, and point b is the operating point of the same drive torque T1 and actual phase current ib_ref, and ib_ref ​​is greater than ia_ref (leading to losses of the motor and electronic control in the three-in-one powertrain, with Loss_a less than Loss_b). The transfer speed from point A to point B and the position at point B (i.e., the current magnitude at point B) are set according to the heating demand of the passenger compartment; when the heating demand is high, the transfer rate is high, and the phase current at point B is higher than that at point A; when the heating demand is low, the transfer rate is low, and the phase current at point B is lower than that at point A; the command current for the drive motor's d-axis... and q-axis command current The calculation method is as follows: Point A: ; Point b: ; in, , These are the leading phase angles of the motor phase currents at points a and b, respectively. V_am: Maximum permissible stator phase voltage limit for the drive motor; I_am: Maximum allowable stator phase current limit for the drive motor; Additionally, the MTPV (Maximum Torque Per Voltage) curve shown in the figure is the maximum torque-voltage ratio control curve, and the characteristic current is expressed by the following formula: .

[0049] Furthermore, the drive motor is controlled using the sliding mode model predictive control (SMMPC) algorithm to improve the dynamic response speed and control accuracy of the motor. The control process of the SMMPC algorithm includes: The torque command issued by the vehicle controller (VCU) is converted into the command current in the dq coordinate system, and the current limit circle and voltage limit circle are calculated in real time in combination with the motor parameters. The motor voltage equation in the dq coordinate system is discretized based on the first-order Euler discretization method to obtain the motor stator current prediction equation at time k+1. Construct d-axis and q-axis control sliding surfaces, and calculate d-axis and q-axis command voltages using exponential approach rates; The command voltage in the dq rotating coordinate system is converted into the voltage in the α and β stationary coordinate systems. Based on the voltage space vector pulse width modulation algorithm SVPWM (Space Vector Pulse Width Modulation) or DSVPMW (Distributed Space Vector Pulse Width Modulation), six PWM signals are generated to drive the power devices of the motor controller to control the drive motor.

[0050] The specific implementation of the Sliding Mode Model Predictive Control (SMMPC) algorithm is as follows: Step 1: Set the torque of the drive motor in the three-in-one powertrain: The vehicle control unit (VCU) issues torque commands to the drive motors. To meet these torque requirements, the drive motors in the three-in-one powertrain are converted into command currents for the d-axis and q-axis, which then control the drive motors. The electromagnetic torque of the drive motor is expressed by the following formula: (1) ; Number of rotor pole pairs; The magnetic flux of the air gap magnetic field generated by the rotor magnet is the magnetic field generated by the magnet itself. d-axis motor inductance; q-axis motor inductance; , Commands for the d-axis and q-axis currents in the dq coordinate system; Step 2: Set the amplitude of the stator current vector of the drive motor. (2) ; : Amplitude of the stator current vector of the drive motor The maximum allowable stator phase current vector value for the drive motor; Step 3: Calculate the current values ​​for the d-axis and q-axis; (3) ; : The magnitude of the stator current vector of the drive motor; The leading phase angle of the motor phase current; Step 4: When performing MTPA (Max Torque Per Ampere) control on the drive motor, the lead phase angle of the motor phase current can be calculated using the following formula: (4) ; Step 5: Calculate the d-axis command current in the dq coordinate system: (5) ; Step 6: Calculate the q-axis command current in the dq coordinate system: (6) ; Step 7: Perform MTPA (Max Torque Per Ampere) control on the drive motor: (7) ; : The maximum permissible stator phase voltage limit for the drive motor; Phase voltage limit value without considering the phase resistance of the drive motor; Step 8: Calculate the drive current limiting circle and voltage limiting circle: (8) ; (9) ; (10) ; Terminal voltage in steady state; Voltage limit value; d-axis motor voltage; : q-axis motor voltage; Simplified limiting equation for motor voltage: (11) ; = - ; : The maximum permissible stator phase current limit value for the drive motor; (12) ; Step 9: Calculate d - q coordinate system d shaft and q Axis voltage equation: (13) ; The magnetic flux of the air gap magnetic field generated by the rotor magnet is the magnetic field generated by the magnet itself.

[0051] d-axis motor current; q-axis motor current; d-axis motor inductance; q-axis motor inductance; Motor rotor magnetic pole deviation angle ( ); Motor phase resistance; Angular velocity of the motor rotor; d-axis motor current, ; q-axis motor current, ; Peak value of motor phase current; ; The leading phase angle of the motor current starting from the q-axis.

[0052] Step 10: Transforming the above equation, we get: (14) ; Discretizing the above equation using the first-order Euler discretization method yields: (15) ; Based on Model Predictive Control (MPC), the above equation is transformed to obtain k Prediction equation for motor stator current at +1 time: (16) ; Deformation k Prediction equations for the stator command voltage of the d-axis and q-axis motors at time +1: (18) ; d-axis drive motor command current; q-axis drive motor command current; : Command voltage for the d-axis drive motor; : Command voltage for the q-axis drive motor; Inventing the Sliding Mode Model Predictive Control (SMMPC) algorithm: ; ; Step 11: Calculate the control sliding surface: (19) ; , Two sliding surfaces, d-axis and q-axis; , Commands for the d-axis and q-axis currents in the dq coordinate system; , : dq coordinate system k The actual d-axis and q-axis predicted currents at time +1 are calculated using formula (16) for the first derivatives of the two sliding surfaces: (20) ; Exponential convergence rate: (twenty one) ; and For the approach rate parameter, , ; Step 12: Calculate the d-axis control sliding surface: (twenty two) ; (twenty three) ; Step 13: Calculate the q-axis control sliding surface: (twenty four ; (25) ; Step 14: Stator voltage equations in the dq rotating coordinate system: (26) ; (27) ; Forgetting factor, used to weaken the cumulative effect of aperiodic disturbances; >0. Learning gain factor >0.

[0053] Relative to the q-axis, (28) ; ; ; ; Step 15: Transform into Stator voltage equation in stationary coordinate system: (29) ; Motor rotor angle; Step 16: Based on the space vector pulse width modulation (SVPWM) algorithm, the drive motor is controlled by the motor controller.

[0054] Space Vector Pulse Width Modulation (SVPWM) algorithm: Based on the discrete switching state combinations of 6 IGBT or SiC power devices in a three-phase motor controller, it generates a specific pulse width modulation waveform. The 6 switching devices have 8 switching states: This includes six active vectors V1

[100] , V2

[110] , V3

[010] , V4

[011] , V5

[001] , and V6

[100] , and two zero vectors V0

[100] and V7

[110] . These eight voltage space vectors are plotted on... , In a stationary coordinate system, they divide the coordinate plane into 6 regions, which are called sectors.

[0055] At any time t, V 0_ref Let V be a sector located in sector 1-6. 0_ref Located in sector 1, if the switching period T s Small enough that it can be approximated as T s V within a time period 0_ref If it remains unchanged, then based on the volt-second balance principle, V 0_refIn a switching cycle T s The result of the action can be equivalent to the combined action of two adjacent non-zero vectors V1 and V2, and zero vectors V0 and V7 in the sector, over a certain period of time. Or, in other words... , Any rotating spatial vector on the stationary coordinate plane at any given moment can be considered as the result of two adjacent stationary spatial vectors and the zero vector, which can be expressed as: (28) ; In the formula, They are respectively , , , From the duration of action, we can obtain: (29) ; Similarly, we can obtain V 0_ref The voltage vector action time at sectors 2, 3, 4, 5, and 6; generating 6-phase PWM signals to drive 6 groups of IGBTs or SiC power devices to control the drive motor.

[0056] Figure 1 Control block diagram of the electric drive system for the drive motor: A sliding mode model predictive control (SMMPC) algorithm was invented to control the drive motor in the three-in-one powertrain. The specific control block diagram is shown below. The front end uses a boost control algorithm, which, based on the commanded torque, vehicle speed, and battery voltage signals, controls the motor via MTPV (Maximum Torque Per Voltage) and MPTA (Maximum Torque Per Ampere). The new SMMPC control algorithm then generates six drive PWM signals to turn the motor controller's drive circuit on and off, thereby controlling the main drive motor. The SMMPC control algorithm features high performance, including high response, high precision, and high robustness.

[0057] Figure 2 The drive circuit diagram for the electric drive system of the motor: The controller uses a three-phase two-level controller, powered by the vehicle battery, a boost converter circuit, and the main controller. The front end of the controller consists of a boost converter circuit, which comprises two power devices, a reactor, and a filter film capacitor. It adaptively boosts the battery voltage to the optimal level based on the required output torque and power of the drive motor, combined with the battery voltage, further improving efficiency and reducing losses. Additionally, the boost converter circuit, also composed of two power devices and a reactor, adaptively boosts the battery voltage to the optimal level based on the required output torque and power of the drive motor, combined with the battery voltage, further improving efficiency and reducing losses.

[0058] The main motor controller's stator winding control consists of a power module with six IGBTs or MOSFETs and six freewheeling diodes (FWD), thin-film capacitors, and control circuitry, performing real-time control of the stator three-phase current. The main controller's three-phase currents Iu_act, Iv_act, and Iw_act are obtained from current sensors, while the rotor angle signal is obtained from a resolver. Vdc is the vehicle battery voltage. The two-level controller has 2³=8 switching states.

[0059] Figure 3 This is a voltage space vector diagram based on the voltage space vector modulation algorithm SVPWM (Space Vector Pulse Width Modulation). The voltage space vector modulation algorithm SVPWM is based on the discrete switching state combination of 6 IGBT or SiC MOSFE power devices of a three-phase motor controller to generate a specific pulse width modulation waveform.

[0060] It is worth mentioning that the technical features such as the drive motor involved in this patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial arrangement of these technical features can be adopted by conventional choices in the field, and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0061] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. An active lubrication structure, characterized in that, This includes the oil pan, electronic oil pump, coaxial reducer main oil passage, lubrication nozzle assembly, and return oil passage, among which: The oil pan is used to store lubricating oil. The electronic oil pump is integrated inside the three-in-one powertrain. The oil inlet of the electronic oil pump is connected to the oil pan and the oil outlet is sealed to the main oil passage of the coaxial reducer. The lubrication nozzle assembly includes a first nozzle and a second nozzle disposed on the housing of the coaxial reducer, and a third nozzle and a fourth nozzle disposed on the housing connecting the drive motor and the coaxial reducer. Each nozzle is connected to the main oil passage of the coaxial reducer. The first nozzle is positioned towards the meshing point of the double planetary pinion and the internal gear ring, the third nozzle is positioned towards the meshing area of ​​the double planetary gear and the sun gear, and the second nozzle and the fourth nozzle are positioned towards the front and rear oil collection caps, respectively. The oil return circuit includes multiple oil outlets located under the housing where the drive motor and the coaxial reducer are connected. The oil outlets are connected to the oil pan through the oil return channel between the motor housing and the coaxial reducer housing, forming a closed-loop lubrication circuit.

2. A coaxial reducer, characterized in that, Including the active lubrication structure as described in claim 1, it further includes an integrated NW planetary gear reducer, differential assembly, and coaxial reducer housing, wherein: The NW planetary gear reducer includes three tower-type planetary gear assemblies, an internal gear ring, a sun gear, and two front and rear oil collection covers. The oil collection covers have cover holes for collecting oil sprayed from the nozzles and splashed from the gears and flowing into the pins. The tower-type planetary gear assembly consists of tower-type planetary gears, pins, needle roller bearings, and spacers. Each of the three pins throws oil out through two through holes in its inner wall to lubricate the needle roller bearings. The differential assembly includes a differential housing, three bevel-tooth planetary gears and ball bearings, two bevel-tooth half-shaft gears and flat bearings, a coiled pin, a planetary shaft, and a cage. The planetary shaft passes through the inner bore of the bevel-tooth planetary gears and is fixed to the planetary carrier by the coiled pin. Its inner wall has two through holes for throwing out oil to lubricate the inner bore of the planetary gears, the meshing area of ​​the gear teeth, and the ball bearings. The cage is installed at the intersection of the planetary shafts and has three through holes evenly distributed on its side wall for fixing the planetary shafts and achieving precise positioning.

3. An active lubrication control algorithm, applied to the coaxial reducer of claim 2, characterized in that, Includes the following steps: Step S1: Perform parametric modeling and temperature node division on the NW planetary gear reducer and differential assembly, and construct steady-state and transient heat flow balance equations; Step S2: Couple the heat flow balance equation with the thermal network model of the relevant components of the vehicle's three-in-one powertrain, and collect or estimate operating parameters in real time, including motor speed, torque, coaxial reducer oil temperature, oil pressure, gear meshing load, and ambient temperature. Step S3: Based on the coupled thermal network model and combined with the elastohydrodynamic lubrication theory, the minimum oil film thickness of the meshing surface of the bevel planetary gears of the tower planetary gear assembly, internal gear ring, sun gear and differential assembly is predicted in real time, and dynamic calibration is performed through the temperature correction coefficient. Step S4: Determine whether the predicted minimum oil film thickness has reached the preset threshold. If not, dynamically adjust the speed of the electronic oil pump and control the oil injection quantity and oil pressure of the first nozzle, second nozzle, third nozzle, fourth nozzle, and subsequent additional nozzles without limitation in number and position, until the oil film thickness reaches the preset threshold, ensuring that the meshing area of ​​the coaxial reducer gear and the meshing surface of the bevel planetary gear always maintain the best lubrication state. Step S5: Identify the operating conditions of climbing, descending, rapid acceleration, emergency braking, and cornering using the vehicle operating condition identification module. Based on the identification results, optimize the oil injection distribution strategy of each nozzle to ensure that the lubricating oil accurately reaches the target lubrication points.

4. A three-in-one powertrain, characterized in that, The three-in-one powertrain includes a drive motor, a coaxial reducer as described in claim 2, a motor controller, and an oil cooler. It also includes a thermal management control system comprising an oil-cooled internal circulation subsystem and a water-cooled external circulation subsystem. The two subsystems exchange heat through the oil cooler. The oil-cooled internal circulation subsystem consists of a drive motor, a coaxial reducer, an oil cooler, and an adjustable speed oil pump. It shares the lubrication circuit with the active lubrication structure, and the lubricating oil simultaneously undertakes the functions of lubrication and internal cooling. The water-cooled external circulation subsystem consists of a motor controller, a drive motor, a coaxial reducer, an oil cooler, a low-temperature radiator, a water pump, and a passenger compartment heating air box. Cooling water flows sequentially through the motor controller, the oil cooler, the drive motor housing, and the coaxial reducer housing to achieve external cooling and waste heat recovery.

5. A three-in-one powertrain according to claim 4, characterized in that, The thermal management control system has three operating modes: heat dissipation mode, waste heat recovery mode, and heat preservation mode. Heat dissipation mode: When there is no heating requirement in the passenger compartment, and the temperature of the motor, electronic control, coaxial reducer, water temperature, or oil temperature reaches the first warning threshold, the low-temperature radiator is turned on, the blower of the heater box is turned off, and the cooling water dissipates heat to the outside environment through the low-temperature radiator. Insulation mode: When the passenger compartment has a heating requirement, and the temperature of the motor, electronic control, coaxial reducer, water temperature, or oil temperature has not reached the first warning threshold, the residual heat meets the heating requirement of the passenger compartment, and the water temperature has not reached the second warning threshold, the low-temperature radiator and blower are disconnected, and the cooling water circulates to absorb the heat of the three-in-one powertrain to achieve insulation. Waste heat recovery mode: When the crew cabin has a heating demand, the waste heat does not meet the crew cabin heating demand, and the water temperature reaches the second warning threshold, the low temperature radiator is disconnected and the blower is turned on. The cooling water will transfer the absorbed heat to the crew cabin heating air box to achieve crew cabin heating.

6. A three-in-one powertrain according to claim 5, characterized in that, The thermal management control system is equipped with a waste heat heating control algorithm. In waste heat recovery mode, the MTPA control point of the drive motor is switched from point a to point b. While keeping the drive torque constant, the phase current of the drive motor is increased, thereby increasing the losses of the motor and the electronic control to generate more heat. Point a is the operating point of drive torque T1 and actual phase current ia_ref, and point b is the operating point of the same drive torque T1 and actual phase current ib_ref, where ib_ref ​​is greater than ia_ref. The transfer speed from point A to point B and the position at point B are set according to the heating requirements of the crew cabin. When the heating demand is high, the transfer rate is high, and the phase current at point b is higher than that at point a; when the heating demand is low, the transfer rate is low, and the phase current at point b is lower than that at point a.

7. A three-in-one powertrain according to claim 6, characterized in that, The drive motor is controlled using the sliding mode model predictive control (SMMPC) algorithm to improve the dynamic response speed and control accuracy of the motor. The control process of the SMMPC algorithm includes: The torque command issued by the vehicle controller (VCU) is converted into the command current in the dq coordinate system, and the current limit circle and voltage limit circle are calculated in combination with the real-time parameters of the motor. The motor voltage equation in the dq coordinate system is discretized based on the first-order Euler discretization method to obtain the motor stator current prediction equation at time k+1. Construct d-axis and q-axis control sliding surfaces, and calculate d-axis and q-axis command voltages using exponential approach rates; The command voltage in the dq rotating coordinate system is converted into the voltage in the α and β stationary coordinate systems. Based on the voltage space vector pulse width modulation algorithm (SVPWM), six PWM signals are generated to drive the power devices of the motor controller to control the drive motor.

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