A wheel hub motor dual-mode driving control method, system and storage medium

Abstract

The application relates to the field of electric vehicle driving control, in particular to a wheel hub motor dual-mode driving control method and system and a storage medium, which solve the problem that a single control mode is difficult to balance power and smoothness. According to the application, six-step square wave and SVPWM sine wave control are intelligently switched according to vehicle speed, square waves are used in the starting stage to meet the demand for large torque, and sine waves are used in the running stage to ensure running smoothness; the sine wave control is based on an improved FOC architecture, a segmented cubic function improved sliding mode algorithm is used to replace the traditional PI algorithm to optimize the speed loop and the torque loop, and a vehicle stability judgment module is integrated, linear smooth switching of the speed / torque control is realized, and the posture of an unstable vehicle can be adjusted through additional yaw moment. The application also designs a matching driving control system and a hardware storage medium, and the hardware is integrated and supports online debugging and configuration. The application improves motor control precision and vehicle stability, realizes full-condition performance optimization, and has strong adaptability.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle drive control technology, specifically to a dual-mode drive control method, system, and storage medium for a hub motor. Background Technology

[0002] In-wheel motors have become an important development direction for electric vehicles due to their compact structure, high efficiency, and ease of distributed drive. Currently, mainstream square wave control offers high starting torque but noticeable low-speed pulsation; sine wave control provides smooth and efficient operation but has relatively limited starting and overload capabilities. Existing single control modes struggle to balance power and smoothness across all operating conditions. Furthermore, in distributed drive systems, dynamically adjusting control targets (speed / torque) based on vehicle stability to achieve active attitude control is crucial for improving safety. Therefore, a refined in-wheel motor drive solution capable of intelligently switching control modes and integrating vehicle stability criteria is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a dual-mode drive control method, system, device, and storage medium for in-wheel motors. This method can intelligently switch between square wave and sine wave control modes according to the vehicle's operating status, balancing starting performance and smooth operation. Simultaneously, in sine wave control mode, an advanced in-wheel motor controller based on an improved sliding mode algorithm and a vehicle stability determination module are integrated to achieve adaptive switching between speed control and torque control, thereby comprehensively improving the vehicle's dynamic response and handling stability.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The traditional field-oriented control architecture is referred to as FOC, and the space vector pulse width modulation technology is referred to as SVPWM.

[0006] Based on the characteristics of high output power under square wave control and low torque fluctuation and smooth operation under sine wave control, the hub motor adopts a dual-mode drive control method using both square wave and sine wave, with the specific rules as follows:

[0007] (1) Monitor the rotational speed of the hub motor and calculate the vehicle speed based on the rotational speed; determine the current state of the vehicle based on the rotational speed and vehicle speed, the state including the stopped state, the starting stage and the running stage; when the vehicle is determined to be in the starting stage, control the hub motor to drive in square wave control mode; when the vehicle is determined to be in the running stage, control the hub motor to switch to sine wave control mode.

[0008] (2) If the rotation speed is zero and continues for a first preset duration, the vehicle is determined to be in a stopped state. The preset duration can be set to a time point or a time range, such as 3s or 2-5s. If the vehicle speed starts to rise from zero and is lower than the preset speed threshold, the vehicle is determined to be in the starting stage. The speed threshold can be set to a speed value or a speed range, such as 10km / h or 10-20km / h. If the vehicle speed reaches or exceeds the preset speed threshold, the vehicle is determined to be in the running stage.

[0009] (3) The square wave control mode is a six-step square wave control, and the sine wave control mode is implemented through SVPWM control technology.

[0010] Furthermore, during vehicle operation, the hub motor adopts sinusoidal wave control, which is based on the traditional field-oriented control (FOC) architecture and has been improved. This architecture includes a signal acquisition module, an improved sliding mode speed loop controller, an improved sliding mode torque loop controller, a coordinate transformation and drive module, and a vehicle stability determination and control module.

[0011] The signal acquisition module is used to acquire and store the actual rotational speed of the hub motor. Rotating coordinate system Shaft actual current , Shaft actual current and vehicle operating status parameters; the vehicle operating status parameters include yaw rate. , centroid side slip angle Vehicle speed Steering angle .

[0012] The improved sliding mode speed loop controller is constructed based on a piecewise cubic function-based improved sliding mode control algorithm. This algorithm replaces the sign function in traditional sliding mode control with a piecewise cubic function, effectively suppressing chattering. The speed loop controller receives the actual speed output by the signal acquisition module. And the expected speed calculated based on the vehicle stability assessment and control module. The improved sliding mode algorithm is used to calculate and output the results. Shaft reference current .

[0013] The improved sliding mode torque loop controller is also built based on the piecewise cubic function improved sliding mode control algorithm, with the input... shaft and The shaft current error signal is calculated using an improved sliding mode torque loop. Shaft control voltage , Shaft control voltage .

[0014] The coordinate transformation and driving module includes a Park inverse transformation unit and a space vector pulse width modulation (SVPWM) unit; the Park inverse transformation unit receives the output of the improved sliding mode torque loop controller. , The SVPWM unit converts the three-phase AC signal into a motor drive signal and outputs it to the hub motor to drive its operation.

[0015] Furthermore, the speed loop controller in the sinusoidal control architecture is designed using an improved sliding mode control algorithm:

[0016] The piecewise cubic function is expressed as follows:

[0017]

[0018] in, The coefficients of a cubic function, .

[0019] The power-law approach law of the sliding mode control algorithm is expressed as follows:

[0020]

[0021] in, This is the control rate coefficient. ; This is the control rate index coefficient. .

[0022] Substituting the piecewise cubic function into the sliding mode control law, the expression is as follows:

[0023]

[0024] The sign function in the sliding mode control law is replaced with a piecewise cubic function to improve the sliding mode algorithm. This improved sliding mode control algorithm then replaces the PI algorithm for the speed loop in the traditional FOC, thus reconstructing the speed loop.

[0025] Define hub motor speed error And simultaneously establish the torque balance equations:

[0026]

[0027] in, This is the reference speed for the hub motor. This refers to the actual rotational speed of the hub motor. For electromagnetic torque, The damping coefficient is... For load torque, Let be the moment of inertia.

[0028] The wheel hub motor speed error was calculated. The derivative:

[0029]

[0030] The hub motor model contains differential terms. To reduce errors and ensure system convergence, an integral sliding surface is designed. :

[0031]

[0032] in, , is the rotational speed slip coefficient.

[0033] Differentiate with respect to the sliding surface:

[0034]

[0035] Substitute the improved sliding mode control law:

[0036]

[0037] in, , This is the coefficient corresponding to the speed slip mode control rate.

[0038] Calculate the output of the speed loop :

[0039]

[0040] Electromagnetic torque equation for hub motor:

[0041]

[0042] in, For extreme logarithms, Rotating coordinate system shaft current, For stator flux linkage.

[0043] Substituting the electromagnetic torque equation into the speed loop The output equation yields the output current of the speed loop. :

[0044]

[0045] Furthermore, the torque loop controller in the sinusoidal control architecture is designed using an improved sliding mode control algorithm:

[0046] Decoupling rotating coordinate systems using Park transformation After shaft current, control is required. The shaft current is 0. Define them separately. Shaft current error and Shaft current error :

[0047]

[0048]

[0049] in, Rotating coordinate system Shaft reference current, Rotating coordinate system Shaft reference current, Rotating coordinate system Actual shaft current.

[0050] Differential equation of current in rotating coordinate system:

[0051]

[0052]

[0053] in, For stator resistance, , They are respectively , shaft voltage, for , The axial inductance components are assumed to be equal on both sides.

[0054] Substituting the derivative of the current error into the current differential equation:

[0055]

[0056]

[0057] Similar to the improved sliding mode algorithm for the same rotational speed loop, it uses an integral sliding surface:

[0058]

[0059]

[0060] in, , Torque loop , Shaft current sliding surface, , , , Torque loop , Shaft current sliding surface coefficient.

[0061] Differentiate with respect to the sliding surface:

[0062]

[0063]

[0064] Substitute the improved sliding mode control law:

[0065]

[0066]

[0067] in, , , , This is the coefficient corresponding to the torque sliding mode control rate.

[0068] Calculate the torque loop output , :

[0069]

[0070]

[0071] Furthermore, the sine wave control includes a vehicle stability determination and control module:

[0072] The vehicle stability determination and control module is used to pre-store vehicle stability criteria, determine whether the current vehicle operating condition is a steady-state condition or an extreme instability condition based on the vehicle operating state parameters, and output an operating condition determination signal. When the condition is determined to be steady-state, a speed control mode command is output, with the FOC architecture primarily using speed loop control; when the condition is determined to be extreme instability, a torque control mode command is output, with the FOC architecture primarily using torque loop control; the vehicle speed and torque control submodules can also achieve linear and smooth conversion between hub motor speed and torque control modes.

[0073] The vehicle stability assessment and control module receives the vehicle's yaw rate. , centroid side slip angle Speed Steering angle Vehicle status parameters, based on phase plane or Stability is determined by considering phase plane stability conditions. When the yaw rate... and centroid side slip angle All conditions are within the stability range, the vehicle is stable, the hub motors use speed control, and the speed of the distributed drive hub motors needs to meet the Ackermann steering model; when the yaw rate and centroid side slip angle When at least one parameter is outside the stability condition range, the vehicle becomes unstable. The hub motors use torque control to generate an additional yaw moment by controlling the torque output of each distributed hub motor. To adjust the vehicle's posture.

[0074] When the hub motor uses speed control, the speed loop of the FOC architecture is controlled first, and the torque control submodule only transmits the torque control information. Value, that is The vehicle stability assessment and control module calculates the desired speed of each motor. The speed control submodule will control the desired speed. The reference speed is input to the comparison stage at the front end of the speed loop. , and actual speed By performing a difference comparison, the actual speed of the hub motor is ensured to track the desired speed in real time.

[0075] When the hub motor uses torque control, the torque loop of the FOC architecture is controlled first, and the speed control submodule only transmits the torque. Value, that is The vehicle stability assessment and control module uses an additional yaw moment. And the torque distribution rules calculate the desired torque of each motor. The torque control submodule will control the desired torque. Signal converted into current The signal is transmitted to the front end of the torque loop. Shaft current comparison circuit, input reference current , with actual current By performing a difference comparison, we can ensure that the actual torque of the hub motor tracks the desired torque in real time.

[0076] When the speed control switches to torque control instantaneously, the output value at a certain moment of the speed loop front end... With the desired current There is a difference, at this time by Instantly switch to This will cause the torque loop front end Shaft input reference current A step change occurs, affecting the accuracy and effectiveness of torque control. At this time, the torque control submodule will linearize the input reference current during the transition.

[0077]

[0078] in, This is the transition period for switching torque between speed and speed.

[0079] When torque control switches to speed control instantaneously, speed control changes from secondary control to primary control. The actual input speed at this moment is compared in the front-end comparison circuit of the speed loop. With the desired speed There may be a difference, which could cause the input speed reference value in the front-end comparison circuit of the speed loop to be affected. A sudden abrupt change occurs, affecting the accuracy and effectiveness of speed control. In this situation, the speed control submodule will linearize the input reference speed during the transition.

[0080]

[0081] in, This is the transition period for switching speed from torque to torque.

[0082] This invention provides a dual-mode drive control system for a hub motor, used to implement the method described in the first aspect, the system comprising:

[0083] The monitoring unit is used to monitor the rotational speed and rotor angle of the hub motor in real time.

[0084] The mode determination unit, connected to the monitoring unit, is used to calculate the vehicle speed based on the rotation speed signal and determine whether the vehicle is in a stopping phase, starting phase, or running phase according to a preset determination rule. When the mode determination unit determines that the vehicle is in the starting phase, it controls the drive unit to output a six-step square wave drive signal; when it determines that the vehicle is in the running phase, it controls the drive unit to output an SVPWM drive signal.

[0085] The square wave control unit includes a memory, software program, processor, and internal bus / communication interface. The memory stores the square wave control program, the processor loads and executes the square wave control program, and the processor transmits the square wave drive signal to the communication interface through the internal bus. The drive signal is then sent to the hub motor body through an external signal line, driving the hub motor to operate according to the six-step square wave method. At the same time, the hub motor feeds back the back EMF, Hall element, or resolver encoder signal to the control system communication interface in real time through the signal line. The processor receives the feedback signal through the internal bus, further tunes the drive algorithm, and outputs a more accurate square wave drive control signal.

[0086] The sine wave control unit includes a memory, software program, processor, and internal bus / communication interface. The memory stores the sine wave control program and the vehicle stability judgment and control program. The processor loads and executes the sine wave control program and the vehicle stability judgment and control program. The processor transmits the sine wave drive signal to the communication interface through the internal bus and sends the drive signal to the wheel hub motor body through the external signal line. The drive signal controls the speed or torque of the wheel hub motor in SVPWM mode. At the same time, the wheel hub motor feeds back the back EMF, Hall element, or resolver encoder signal to the control system communication interface in real time through the signal line. The processor receives the feedback signal through the internal bus, further judges the vehicle stability state, selects the speed control mode or torque control mode, tunes the sine wave control algorithm, and drives the wheel hub motor to run.

[0087] The vehicle features distributed in-wheel motors, which drive the vehicle in various configurations including front-wheel drive, rear-wheel drive, and four-wheel drive. Front-wheel drive uses two in-wheel motors, rear-wheel drive uses two in-wheel motors, and four-wheel drive uses four in-wheel drive. Each in-wheel motor can receive square wave or sine wave control signals and correspondingly employs a six-step square wave or sine wave control mode for driving. In sine wave control mode, it can switch between speed control and torque control modes based on the vehicle's stability. The in-wheel motors are configured to simultaneously receive drive signals and feed back their own operating status signals in real time to the corresponding square wave / sine wave drive module for program updates and precise control of the motor itself.

[0088] This invention provides an electronic device and a storage medium, comprising the following components:

[0089] The programmable memory device, which is an FPGA chip or an erasable flash memory chip, is integrated on the printed circuit board of the electronic device by on-board soldering. The programmable memory device is connected to the processor via an SPI bus or an I2C bus and is located in an independent anti-static protection area inside the device housing. Its grounding pin is connected to the device grounding system.

[0090] The programmable storage device stores computer programs, including square wave control programs, sine wave control programs, and vehicle stability determination and control programs.

[0091] A processor, connected to the programmable memory device via a board-level bus, is used to load and execute the computer program to implement the dual-mode drive control method for the hub motor as described in the first aspect and the speed and torque control method in the sine wave control mode; the processor is configured as follows:

[0092] It receives the hub motor speed and rotor angle signals from the monitoring unit, and controls the drive unit to switch between the six-step square wave drive signal and the SVPWM drive signal through an electronic switch according to the preset judgment rules;

[0093] During the startup phase, a six-step square wave control is executed, and a six-step square wave drive signal is output based on the feedback signal.

[0094] During operation, sinusoidal wave control and vehicle stability determination are performed. Based on the feedback signal, the speed or torque control mode is selected, the algorithm is tuned, and the SVPWM drive signal is output.

[0095] A debugging interface, connected to the programmable storage device, is used to update or adjust the stored computer program online to adapt to hub motors of different specifications.

[0096] The electronic device is a motor controller for vehicle drive.

[0097] The beneficial effects of this invention are as follows:

[0098] 1. Optimized performance under all operating conditions: By intelligently switching between square wave and sine wave control modes based on vehicle speed threshold, the high output characteristics of square wave control are used during the start-up phase to meet the high torque requirements during vehicle acceleration; during the operation phase, the smooth and efficient characteristics of sine wave control are used to reduce torque pulsation, achieving the best balance between vehicle power and smoothness under all operating conditions, and significantly improving the operating efficiency of the hub motor.

[0099] 2. Improved Control Accuracy and Robustness: In the FOC architecture of sinusoidal wave control, an improved sliding mode control algorithm based on piecewise cubic functions is adopted to replace the traditional PI controller, applied to both the speed and torque loops. The piecewise cubic function replaces the sign function in traditional sliding mode control, effectively suppressing system chattering while retaining the strong robustness of sliding mode control. This enhances the adaptability to parameter changes and external disturbances, improves dynamic response speed and tracking accuracy, and makes motor control more precise and operation more stable.

[0100] 3. Integrated Vehicle Stability Control: The system innovatively integrates the vehicle stability assessment module deeply into the motor drive control. It can determine stability based on real-time vehicle conditions (yaw rate, sideslip angle, etc.) and autonomously switch between speed control and torque control modes. When the vehicle is stable, speed control is performed based on the Ackermann steering model to ensure steering accuracy. Under unstable conditions, yaw correction torque is generated by distributing torque to each wheel hub motor, achieving active stability control at the chassis level and improving vehicle safety limits. This is particularly suitable for attitude control in distributed drive vehicles.

[0101] 4. Smooth and Uninterrupted Mode Switching: A dedicated linear transition algorithm is designed for the instantaneous switching between speed and torque control modes within the sinusoidal wave control. By linearizing the reference current or reference speed, abrupt changes in the reference signal are avoided, ensuring the smoothness of the switching process and the continuity of control. This eliminates the impact of switching shocks on the motor and vehicle, improving ride comfort and system reliability.

[0102] 5. Highly Integrated and Configurable Hardware: By employing programmable memory devices (FPGA / Flash) to store the core algorithm, combined with a dedicated processor, debugging interface, and anti-static protection design, the control system achieves hardware integration, algorithm reconfigurability, and adaptability flexibility. The debugging interface supports online program updates and parameter adjustments, facilitating product upgrades and rapid matching with different specifications of hub motors, reducing engineering application costs, and demonstrating excellent practicality and scalability. Attached Figure Description

[0103] Figure 1 This is a schematic diagram of the dual-mode drive control method for a hub motor provided in an embodiment of the present invention.

[0104] Figure 2 A flowchart of a dual-mode drive control method for a hub motor provided in an embodiment of the present invention;

[0105] Figure 3 This is a block diagram illustrating the principle of the sine wave control architecture in an embodiment of the present invention.

[0106] Figure 4 A comparison graph of the sign function and the piecewise cubic function;

[0107] Figure 5 This is a flowchart illustrating the algorithm principle of the improved sliding mode speed loop controller in an embodiment of the present invention.

[0108] Figure 6 This is a flowchart illustrating the algorithm principle of the improved sliding mode torque loop controller in an embodiment of the present invention.

[0109] Figure 7 This is a flowchart illustrating the working principle of the vehicle stability determination and control module in this embodiment of the invention.

[0110] Figure 8 This is a schematic diagram illustrating the linear transition during the switching of speed and torque control modes in the sinusoidal control process of this invention, wherein... Figure 8 (a) is a schematic diagram of the linear transition from speed control to torque control. Figure 8 (b) is a schematic diagram of the linear transition from torque control to speed control;

[0111] Figure 9This is a schematic diagram of the structure of the dual-mode drive control system for a hub motor provided in an embodiment of the present invention. Detailed Implementation

[0112] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0113] Figure 1 This diagram illustrates the principle of the dual-mode drive control method for a hub motor provided in this embodiment of the invention, showing the overall framework of the method. Based on the characteristics of high output power from square wave control and low torque fluctuation and smooth operation from sine wave control, the hub motor adopts a dual-mode drive control method using both square wave and sine wave. Specifically, during vehicle startup, the mode switching switch in the control system is connected to the six-step square wave control module, and the hub motor uses the six-step square wave control mode. During vehicle operation, the mode switching switch in the control system is connected to the sine wave control module, and the hub motor uses the sine wave control mode.

[0114] Figure 2 This is a flowchart illustrating the dual-mode drive control method for a hub motor provided in an embodiment of the present invention. After the system is powered on, it continuously monitors the hub motor speed and calculates the vehicle speed. First, it determines whether the vehicle speed is 0 and the duration is greater than [a certain value]. ( The settings can be adjusted according to actual working conditions (e.g., set to 3 seconds). If the judgment condition is met, the vehicle is determined to be in a stopped state, the wheel hub motor does not start, and it is in standby mode; if the judgment condition is not met, it further judges whether the vehicle speed is greater than 0 and lower than the preset value. ( The settings can be adjusted according to actual working conditions (e.g., set to 10km / h). If the vehicle speed is within the preset range, the vehicle is determined to be in the starting phase, and the hub motors adopt a six-step square wave control mode. If the vehicle speed exceeds the preset range, the vehicle is determined to be in the running phase, and the hub motors adopt a sine wave control mode. Further, the vehicle's stability is assessed. If the vehicle is stable, the desired speed of the distributed hub motors is calculated based on the Ackerman steering model, and the hub motor speed is controlled accordingly. If the vehicle is in a state of extreme instability, the desired torque of the distributed hub motors is calculated and allocated according to the hub motor vehicle stability control strategy, and the hub motor torque is controlled accordingly.

[0115] Figure 3The sine wave control architecture is described in detail. This architecture is an improvement on the FOC control architecture and is the core of the invention to achieve high-performance operation. The improved sine wave control architecture includes a signal acquisition module, an improved sliding mode speed loop controller, an improved sliding mode torque loop controller, a coordinate transformation and drive module, and a vehicle stability determination and control module.

[0116] The signal acquisition module obtains the motor speed. Rotor position Rotating coordinate system Shaft actual current , Shaft actual current and yaw rate , centroid side slip angle Vehicle speed Steering angle Vehicle status parameters provide data support for vehicle stability assessment and control modules.

[0117] The improved sliding mode speed loop controller is constructed based on a piecewise cubic function-based improved sliding mode control algorithm. This algorithm replaces the sign function in traditional sliding mode control with a piecewise cubic function, such as... Figure 4 As shown, the piecewise cubic function significantly reduces chattering of the control signal without sacrificing the strong robustness of sliding mode control.

[0118] The piecewise cubic function is expressed as follows:

[0119]

[0120] in, The coefficients of a cubic function, (For example, take) ).

[0121] The power-law approach law of the sliding mode control algorithm is expressed as follows:

[0122]

[0123] in, This is the control rate coefficient. (For example, take) ); This is the control rate index coefficient. (For example, take) ).

[0124] Substituting the piecewise cubic function into the sliding mode control law, the expression is as follows:

[0125]

[0126] The improved sliding mode speed loop controller employs an improved sliding mode control algorithm design. It replaces the sign function in the sliding mode control law with a piecewise cubic function, and replaces the PI algorithm in the traditional FOC speed loop with the improved sliding mode algorithm, thus reconstructing the speed loop. Figure 5 The algorithm principle and flow of the improved sliding mode speed loop controller in the embodiments of the present invention are demonstrated.

[0127] Define hub motor speed error And simultaneously establish the torque balance equations:

[0128]

[0129] in, This is the reference speed for the hub motor. This refers to the actual rotational speed of the hub motor. For electromagnetic torque, For example, take the damping coefficient (e.g., take...). ), This is the load torque (calculated in real time based on actual road conditions). For the moment of inertia (e.g., take...) ).

[0130] The wheel hub motor speed error was calculated. The derivative:

[0131]

[0132] The hub motor model contains differential terms. To reduce errors and ensure system convergence, an integral sliding surface is designed. :

[0133]

[0134] in, , For the rotational speed slip coefficient (e.g., taking respectively) , ).

[0135] Differentiate with respect to the sliding surface:

[0136]

[0137] Substitute the improved sliding mode control law:

[0138]

[0139] in, , The coefficients corresponding to the speed slip mode control rate (e.g., taking the following values ​​respectively) , ).

[0140] Calculate the output of the speed loop :

[0141]

[0142] Electromagnetic torque equation for hub motor:

[0143]

[0144] in, For extreme logarithms (e.g., taking...) ), Rotating coordinate system shaft current, For stator flux linkage (e.g., take) ).

[0145] Substituting the electromagnetic torque equation into the speed loop The output equation yields the output current of the speed loop. :

[0146]

[0147] The torque loop controller in the sinusoidal wave control architecture is designed using an improved sliding mode control algorithm. Figure 6 This is the algorithm principle flow of the improved sliding mode torque loop controller in this embodiment of the invention. First, the Park transformation is used to decouple the rotating coordinate system. After shaft current, control is required. The shaft current is 0. Define them separately. Shaft current error and Shaft current error :

[0148]

[0149]

[0150] in, Rotating coordinate system Shaft reference current (value is output by speed loop) Or desired current ), Rotating coordinate system Shaft reference current (set to 0). Rotating coordinate system Actual shaft current.

[0151] Differential equation of current in rotating coordinate system:

[0152]

[0153]

[0154] in, For the stator resistance (e.g., take...) ), , They are respectively , shaft voltage, for , Axial inductance components (assuming the two axial inductance components are equal, for example, take...) ).

[0155] Substituting the derivative of the current error into the current differential equation:

[0156]

[0157]

[0158] Similar to the improved sliding mode algorithm for the same rotational speed loop, it uses an integral sliding surface:

[0159]

[0160]

[0161] in, , Torque loop , Shaft current sliding surface, , , , Torque loop , Shaft current sliding surface coefficient (e.g., taking respectively) , , , ).

[0162] Differentiate with respect to the sliding surface:

[0163]

[0164]

[0165] Substitute the improved sliding mode control law:

[0166]

[0167]

[0168] in, , , , The corresponding coefficients for torque slip mode control rate (e.g., taking...) , , , ).

[0169] Calculate the torque loop output , :

[0170]

[0171]

[0172] The principle flowchart of vehicle stability determination and control module in sine wave control is as follows: Figure 7 As shown, the vehicle stability determination and control module is used to pre-store vehicle stability criteria, determine whether the current operating condition of the hub motor vehicle is a steady-state condition or an extreme instability condition based on the vehicle's operating state parameters, and outputs an operating condition determination signal. The vehicle stability determination and control module receives the vehicle's yaw rate. , centroid side slip angle Speed Steering angle Vehicle status parameters, based on phase plane or Stability conditions such as phase plane are used to determine vehicle stability. For example, using... Phase plane stability condition: and (in , , The coefficient of adhesion for dry asphalt pavement. Slippery road surface ).

[0173] When the yaw rate and centroid side slip angle All conditions are within the stability range, and vehicle stability is determined. The vehicle stability determination and control module outputs speed control instructions to the wheel hub motors. The improved FOC architecture primarily uses speed loop control. The vehicle stability determination and control module receives the vehicle's yaw rate. , centroid side slip angle Speed Steering angle Based on the Ackermann steering model and other vehicle state parameters, the expected speeds of each wheel hub motor in a distributed drive vehicle are calculated. For example, for a rear-wheel drive vehicle, the expected rotational speeds of the left and right rear wheels are: , (in The wheelbase is the distance between the wheels. Wheelbase (For the wheel radius). Then the speed control submodule inputs the reference speed to the front-end comparison stage of the speed loop in the improved FOC architecture. , and actual speed By performing a difference comparison, the actual speed of the hub motor is ensured to track the desired speed in real time.

[0174] Figure 8 (a) Demonstrates the linear transition effect when switching from speed control to torque control. At the instant of switching from torque to speed control, the actual input speed at a certain moment is compared in the front-end comparison circuit of the speed loop. With the desired speed The existence of a difference will cause the input speed reference value in the front-end comparison circuit of the speed loop to be affected. A sudden abrupt change occurs, affecting the accuracy and effectiveness of speed control. In this situation, the speed control submodule will linearize the input reference speed during the transition.

[0175]

[0176] in, The transition period for torque to speed switching (e.g., taking...) ).

[0177] When the yaw rate and centroid side slip angle If at least one parameter is outside the stability condition range, the vehicle is determined to be unstable. The vehicle stability determination and control module outputs torque control instructions to the wheel hub motors. The improved FOC architecture primarily uses torque loop control. The vehicle stability determination and control module receives the vehicle's yaw rate. , centroid side slip angle Speed Steering angle Based on vehicle state parameters and a built-in yaw stability control strategy, the torque of each in-wheel motor in the distributed drive system is optimally allocated, and the desired torque is output by controlling each in-wheel motor. This causes an additional yaw moment in the vehicle. (For example ,in Let Z be the moment of inertia of the vehicle about the z-axis. (For the desired yaw rate). The torque control submodule will control the desired torque. Signal converted into current Signal( Transmitted to the front end of the torque loop Shaft current comparison circuit, input reference current , with actual current By performing a difference comparison, we can ensure that the actual torque of the hub motor tracks the desired torque in real time.

[0178] Figure 8 (b) Demonstrates the linear transition effect when switching from torque control to speed control. The output value at a certain moment of the speed loop front end is shown when the speed control switches to torque control. With the desired current The existence of a difference will cause the torque loop front end to... Shaft input reference current A step change occurs, affecting the accuracy and effectiveness of torque control. At this time, the torque control submodule will linearize the input reference current during the transition.

[0179]

[0180] in, The transition period for switching torque at different speeds (e.g., taking...) ).

[0181] The coordinate transformation and drive module in the sinusoidal wave control includes a Park inverse transform unit and a space vector pulse width modulation (SVPWM) unit; the Park inverse transform unit receives the output of the improved sliding mode torque loop controller. , Converted into a three-phase alternating current signal ( , , The SVPWM unit converts the three-phase AC signal into a motor drive signal (PWM wave) and outputs it to the hub motor to drive its operation.

[0182] Figure 9 This is a schematic diagram of the structure of the dual-mode drive control system for wheel hub motors provided in an embodiment of the present invention. The dual-mode drive control system for wheel hub motors includes a monitoring unit, a mode determination unit, a square wave control unit, a sine wave control unit, and a vehicle distributed wheel hub motor body.

[0183] The monitoring unit can use a resolver encoder or Hall sensor to collect the speed and rotor angle signals of the hub motor in real time and transmit the signals to the mode determination unit and control unit.

[0184] The mode determination unit uses an MCU chip (such as the STM32H7 series) to receive the speed signal from the monitoring unit and convert it through a speed-vehicle speed conversion model. Calculate the vehicle speed according to the preset judgment rules (stopped state: And continue Start-up phase: Operational phase: It determines the vehicle status and outputs a mode control signal.

[0185] The square wave control unit uses a Flash chip for memory, storing a six-step square wave control program; the processor uses an MCU chip, which loads and executes the square wave control program, generates a six-step square wave drive signal based on the motor rotor angle signal, and transmits it to the hub motor via the CAN bus; at the same time, it receives the back electromotive force signal fed back by the motor, adjusts the duty cycle and frequency of the drive signal, and realizes closed-loop control.

[0186] The sine wave control unit uses an FPGA chip for memory, storing the sine wave control program, vehicle stability determination program, and improved sliding mode algorithm program; the processor uses an FPGA chip to process the current, speed, and vehicle status parameters of the signal acquisition module in real time, execute stability determination and control algorithms, and generate SVPWM drive signals; it communicates with the wheel hub motor controller through a high-speed bus to realize the switching and linear transition of speed / torque control modes.

[0187] The vehicle's distributed hub motors utilize permanent magnet synchronous hub motors, supporting both six-step square wave and sine wave control modes, and can be configured for front-wheel drive, rear-wheel drive, or four-wheel drive. Each hub motor is equipped with an independent controller, receiving drive signals from the control unit, outputting corresponding speed or torque, and providing feedback on operating status signals via a resolver encoder.

[0188] The dual-mode drive control system for hub motors of this invention includes electronic devices and storage media. The programmable memory device uses an FPGA chip (e.g., Xilinx Artix-7 series), integrated onto a printed circuit board via onboard soldering. It connects to the processor via an SPI bus, has an independent anti-static protection area, and its grounding pin is reliably connected to the device grounding system to ensure signal stability. The programmable memory device stores square wave control programs, sine wave control programs, vehicle stability determination programs, and improved sliding mode algorithm programs. The processor uses an ARM Cortex-A series chip, connected to the programmable memory device via an AHB bus, executing the control program to achieve mode switching, algorithm calculation, and drive signal output. The debugging interface uses a JTAG interface, supporting online program updates and parameter adjustments, and is adaptable to hub motors of different power (5-15kW) and different pole pair numbers (2-8 pairs).

[0189] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A dual-mode drive control method for a hub motor, characterized in that, The specific rules are as follows: (1) Monitor the rotational speed of the hub motor and calculate the vehicle speed based on the rotational speed; determine the current state of the vehicle based on the rotational speed and vehicle speed, the state including the stop state, the start-up stage and the running stage; when the vehicle is determined to be in the start-up stage, control the hub motor to drive in square wave control mode; when the vehicle is determined to be in the running stage, control the hub motor to switch to sine wave control mode. (2) If the rotation speed is zero and continues for a first preset time, the vehicle is determined to be in a stopped state; if the vehicle speed rises from zero and is lower than a preset speed threshold, the vehicle is determined to be in the starting stage; if the vehicle speed reaches or exceeds the preset speed threshold, the vehicle is determined to be in the running stage. (3) The square wave control mode is a six-step square wave control, and the sine wave control mode is controlled by space vector pulse width modulation. During vehicle operation, the hub motor uses sinusoidal wave control, and its architecture is as follows: The sinusoidal control is based on a field-oriented control architecture, including a signal acquisition module, an improved sliding mode speed loop controller, an improved sliding mode torque loop controller, a coordinate transformation and drive module, and a vehicle stability determination and control module. The signal acquisition module is used to acquire and store the actual rotational speed of the hub motor. Rotating coordinate system Shaft actual current , Shaft actual current and vehicle operating status parameters; the vehicle operating status parameters include yaw rate. , centroid side slip angle Vehicle speed Steering angle ; The improved sliding mode speed loop controller is constructed based on a piecewise cubic function-based improved sliding mode control algorithm, and receives the actual speed output by the signal acquisition module. And the expected speed calculated by the vehicle stability assessment and control module. Calculate and output Shaft reference current ; The improved sliding mode torque loop controller is constructed based on a piecewise cubic function-based improved sliding mode control algorithm, with the input... shaft and The shaft current error signal is calculated using an improved sliding mode torque loop. Shaft control voltage , Shaft control voltage ; The hub motor uses a sinusoidal wave drive control method, which includes a vehicle stability determination and control module. The vehicle stability determination and control module is used to pre-store vehicle stability criteria, determine whether the current operating condition of the vehicle is a steady-state condition or an extreme instability condition based on the vehicle operating state parameters, and output an operating condition determination signal; when it is determined to be a steady-state condition, it outputs a speed control mode command, and the field-oriented control architecture is mainly based on speed loop control. When the extreme instability condition is determined, the torque control mode command is output, and the field-oriented control architecture is mainly based on torque loop control; the vehicle speed and torque control submodule can also realize the linear and smooth conversion between the wheel hub motor speed and torque control mode. When the hub motor uses speed control, the speed loop of the field-oriented control architecture is controlled first, and the torque control submodule transmits the output value of the speed loop. ,Right now The vehicle stability assessment and control module calculates the desired speed of each motor. The speed control submodule will control the desired speed. The reference speed is input to the comparison stage at the front end of the speed loop. , and actual speed By performing a difference comparison, the actual speed of the hub motor is ensured to track the desired speed in real time. When the hub motor uses torque control, the torque loop of the field-oriented control architecture is controlled first, and the speed control submodule only transmits the desired speed. Value, that is The vehicle stability assessment and control module uses an additional yaw moment. And the torque distribution rules calculate the desired torque of each motor. The torque control submodule will control the desired torque. Signal converted into current The signal is transmitted to the front end of the torque loop. Shaft current comparison circuit, input reference current , with actual current By performing a difference comparison, the actual torque of the hub motor is ensured to track the desired torque in real time. When the speed control switches to torque control instantaneously, the torque control submodule performs a linearization transition on the input reference current: ， in, This is the transition period for switching torque between speeds; When torque control switches instantaneously to speed control, the speed control submodule performs a linear transition on the input reference speed: ， in, This is the transition period for switching speed from torque to torque.

2. The dual-mode drive control method for hub motors according to claim 1, characterized in that... The coordinate transformation and driving module includes a Park inverse transformation unit and a space vector pulse width modulation unit; the Park inverse transformation unit receives the output of the improved sliding mode torque loop controller. , The signal is converted into a three-phase AC signal; the space vector pulse width modulation unit converts the three-phase AC signal into a motor drive signal and outputs it to the hub motor to drive its operation.

3. The dual-mode drive control method for hub motors according to claim 1, characterized in that... The vehicle stability assessment and control module receives the vehicle's yaw rate. , centroid side slip angle Speed Steering angle Vehicle status parameters, based on phase plane or Phase plane stability conditions are used to determine vehicle stability; when the yaw rate... and centroid side slip angle All conditions are within the stability range, the vehicle is stable, the hub motors use speed control, and the speed of the distributed drive hub motors needs to meet the Ackermann steering model; when the yaw rate and centroid side slip angle When at least one parameter is outside the stability condition range, the vehicle becomes unstable. The hub motors use torque control to generate an additional yaw moment by controlling the torque output of each distributed hub motor. To adjust the vehicle's posture.

4. The dual-mode drive control method for hub motors according to claim 1, characterized in that... In the sinusoidal drive control method for hub motors, the speed loop controller in the sinusoidal control architecture adopts an improved sliding mode control algorithm design: The piecewise cubic function is expressed as follows: ， in, The coefficients of a cubic function, ; The power-law approach law of the sliding mode control algorithm is expressed as follows: ，， in, This is the control rate coefficient. ; This is the control rate index coefficient. ; Substituting the piecewise cubic function into the sliding mode control law, the expression is as follows: ， By replacing the sign function in the sliding mode control law with a piecewise cubic function and improving the sliding mode algorithm, the improved sliding mode control algorithm is used to replace the PI algorithm of the speed loop in the traditional field-oriented control, thus reconstructing the speed loop: Define hub motor speed error And simultaneously establish the torque balance equations: ， in, This is the reference speed for the hub motor. This refers to the actual rotational speed of the hub motor. For electromagnetic torque, The damping coefficient is... For load torque, It is the moment of inertia; The wheel hub motor speed error was calculated. The derivative: ， Design an integral sliding surface : ， in, , The rotational speed smoothing coefficient; Taking the derivative with respect to the sliding surface, and substituting it into the improved sliding control law and error derivative: ， in, , This refers to the coefficient corresponding to the speed slip mode control rate; Calculate the output of the speed loop : ， Electromagnetic torque equation for hub motor: ， in, For extreme logarithms, Rotating coordinate system shaft current, For stator flux linkage; Substituting the electromagnetic torque equation into the above equation, we obtain the output current of the speed loop. : 。 5. The dual-mode drive control method for a hub motor according to claim 1, characterized in that, The hub motor can be driven and controlled using a sinusoidal wave method. In the sinusoidal wave control architecture, the torque loop controller is designed with an improved sliding mode control algorithm. Decoupling rotating coordinate systems using Park transformation After shaft current, control The shaft current is 0, and the following definitions are made respectively. Shaft current error and Shaft current error : ， ， in, Rotating coordinate system Shaft reference current, Rotating coordinate system Shaft reference current, Rotating coordinate system Actual shaft current; Differential equation of current in rotating coordinate system: ， ， in, For stator resistance, , They are respectively , shaft voltage, for , The axial inductance components are assumed to be equal. Substituting the derivative of the current error into the current differential equation: ， ， Integral sliding surface is used: ， ， in, , Torque loop , Shaft current sliding surface, , , , Torque loop , Shaft current sliding surface coefficient; Differentiate over the sliding surface and substitute into the improved sliding control law and error derivative: ， ， in, , , , This refers to the coefficient corresponding to the torque slip mode control rate; Calculate the torque loop output , : ， 。 6. A dual-mode drive control system for a hub motor, characterized in that... The system is used to implement the dual-mode drive control method for wheel hub motors according to any one of claims 1 to 5. The system includes a monitoring unit, a mode determination unit, a square wave control unit, a sine wave control unit, and a vehicle distributed wheel hub motor body. The monitoring unit is used to monitor the rotational speed and rotor angle of the hub motor in real time. The mode determination unit, connected to the monitoring unit, is used to calculate the vehicle speed based on the rotation speed signal and determine whether the vehicle is in the stopping phase, starting phase or running phase according to the preset determination rules. When the mode determination unit determines that the vehicle is in the startup phase, it controls the square wave control unit to output a six-step square wave drive signal. When the system is determined to be in the operation phase, the sinusoidal wave control unit is controlled to output a space vector pulse width modulation drive signal. The square wave control unit includes a memory, software program, processor, and internal bus / communication interface. The memory stores the square wave control program, the processor loads and executes the square wave control program, and the processor transmits the square wave drive signal to the communication interface through the internal bus. The drive signal is then sent to the hub motor body through an external signal line, driving the hub motor to operate according to the six-step square wave method. At the same time, the hub motor feeds back the back EMF, Hall element, or resolver encoder signal to the control system communication interface in real time through the signal line. The processor receives the feedback signal through the internal bus, further tunes the drive algorithm, and outputs a more accurate square wave drive control signal. The sine wave control unit includes a memory, software program, processor, and internal bus / communication interface; The memory stores the sine wave control program and the vehicle stability judgment and control program. The processor loads and executes the sine wave control program and the vehicle stability judgment and control program. The processor transmits the sine wave drive signal to the communication interface through the internal bus and sends the drive signal to the wheel hub motor body through the external signal line. The drive signal controls the speed or torque of the wheel hub motor in space vector pulse width modulation mode. At the same time, the wheel hub motor feeds back the back electromotive force, Hall element or resolver encoder signal to the control system communication interface in real time through the signal line. The processor receives the feedback signal through the internal bus, further judges the vehicle stability state, selects the speed control mode or torque control mode, tunes the sine wave control algorithm parameters, and drives the wheel hub motor to run. The vehicle's distributed in-wheel motor unit includes various configurations such as front-wheel drive, rear-wheel drive, and four-wheel drive: front-wheel drive uses two in-wheel motors, rear-wheel drive uses two in-wheel motors, and four-wheel drive uses four in-wheel motors; each in-wheel motor can receive square wave control signals or sine wave control signals, and drive accordingly using a six-step square wave control mode or sine wave control mode; in sine wave control mode, it can switch to speed control mode or torque control mode according to the vehicle's stability status; the in-wheel motor is configured to receive drive signals while simultaneously feeding back its own operating status signals to the corresponding square wave / sine wave drive module in real time for program updates and precise control of the motor unit.

7. An electronic device, characterized in that, include: The programmable memory device, which is an FPGA chip or an erasable flash memory chip, is integrated on the printed circuit board of the electronic device by on-board soldering. The programmable memory device is connected to the processor via an SPI bus or an I2C bus and is located in an independent anti-static protection area inside the device housing. Its grounding pin is connected to the device grounding system. The programmable storage device stores computer programs, including square wave control programs, sine wave control programs, and vehicle stability determination and control programs. A processor, connected to the programmable memory device via a board-level bus, is used to load and execute the computer program to implement the dual-mode drive control method for a hub motor as described in any one of claims 1-5; the processor is configured as follows: It receives the hub motor speed and rotor angle signals from the monitoring unit, and controls the drive unit to switch between the six-step square wave drive signal and the space vector pulse width modulation drive signal through an electronic switch according to the preset judgment rules. During the startup phase, a six-step square wave control is executed, and a six-step square wave drive signal is output based on the feedback signal. During operation, sinusoidal control and vehicle stability determination are performed. Based on feedback signals, speed or torque control mode is selected, algorithm parameters are tuned, and space vector pulse width modulation drive signals are output. A debugging interface, connected to the programmable storage device, is used to update or adjust the stored computer program online to adapt to hub motors of different specifications. The electronic device is a motor controller for vehicle driving.

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