| Compared with centralized driving electric vehicles,the hub motor simplifies the transmission mechanism,and has the advantages of high transmission efficiency,fast response speed and easier torque control.However,in the face of complex driving and braking conditions,it is difficult for a traditional electric vehicle driven by a single inner rotor or a single outer rotor motor to meet the complex driving/braking conditions while maintaining the efficient operation of the motor.At the same time,the double rotor motor is a new type of motor that can realize flexible energy transmission,and can be used as a hub motor to meet the needs of complex running conditions of automobiles.Regenerative braking energy recovery technology can convert part of the kinetic energy of automobile into electric energy during the braking process of the car and store it for automobile driving,which can effectively improve the cruising range of electric automobile.Regenerative braking can generate a certain regenerative braking torque while recovering energy,so it is necessary to adjust the hydraulic braking torque of the original vehicle to meet the braking torque demand of the whole vehicle.Especially in the process of antilock braking,the coordinated control of regenerative braking torque and hydraulic braking torque will directly affect the braking stability of vehicles.Therefore,it is of great significance to carry out research on how to improve the efficiency of braking energy recovery and the coordinated control of regenerative braking and hydraulic ABS in double rotor hub motor.On the basis of the structure of dual-rotor hub motor based on dual-power battery pack proposed in this paper,the research on the coordinated control of variable voltage charging,regenerative braking and hydraulic ABS of dual-rotor hub motor is carried out.The main work is as follows:A structural scheme of double rotor hub motor based on dual-power battery pack is proposed,which is suitable for variable voltage charging of double rotor hub motor.The working principle of double rotor hub motor based on dual-power battery pack is introduced in detail.The combination structure of two groups of power battery packs and two BMS controllers is adopted,and the control of the connection between the inner and outer motors and the first power battery pack and the second power battery pack is realized through the switching module.The single-wheel dynamic model,tire model,electro-hydraulic brake system model,brake equivalent model and dynamic model of double rotor hub motor are established,which lays a foundation for simulation analysis in subsequent research.A variable voltage charging regenerative braking scheme is proposed based on a double rotor hub motor based on dual-power battery packs.Aiming at the structural characteristics of the dual-power battery pack of the double rotor hub motor,a variable voltage charging method for the double rotor hub motor based on the comprehensive weighted variation coefficient is proposed.The simulation results show that the double rotor hub motor variable voltage charging scheme based on the dual-power battery pack has superiority in energy recovery and effectively improves the energy recovery efficiency of the dual-rotor in-wheel motor.A regenerative braking torque control strategy for variable torque coefficient variable voltage charging based on least squares fitting is designed,and simulation research is carried out.Simulation results show that the proposed variable torque coefficient control strategy based on least square fitting is better than the fixed torque coefficient control of the target regenerative braking torque.An anti-lock braking mode discrimination method and its mode switching control strategy suitable for double rotor hub motors are proposed.The anti-lock braking mode of double rotor hub motor based on dual-power battery pack is designed,and the antilock braking mode discrimination scheme suitable for double rotor hub motor is designed according to the road recognition result based on lagrange interpolation polynomial.The hybrid dynamic theory is used to analyze the mode switching process.Model predictive control is used to carry out the research on the torque coordinated control of braking mode switching.The simulation results show that after the model predictive coordinated control strategy is adopted,the mode switching response time is increased by 43.6%,and the jerk is reduced by 31.37%,which effectively reduces the jerk of switching and improves the smoothness of mode switching.The coordinated control method of double rotor hub motor regenerative braking and hydraulic ABS is studied,and a double rotor hub motor regenerative braking and hydraulic ABS coordinated control scheme based on hierarchical control is designed.The upper controller uses the sliding mode variable structure anti-lock control algorithm based on the saturation function approach rate to obtain the required braking torque;the lower controller adopts a step-by-step coordinated control strategy realize the distribution of motor and hydraulic braking torque,and adopts the maximum power-based variable voltage charging regenerative braking control strategy to realize the distribution of regenerative braking torque of the inner and outer motor.Simulation results show that the proposed coordinated control method of regenerative braking and hydraulic ABS for double rotor hub motor has the advantages of high energy recovery efficiency and good braking stability.On the double-rotor hub motor composite braking test platform,the steady-state characteristic test,the dynamic characteristic test and the coordinated anti-lock braking test of double rotor hub motor and hydraulic ABS were carried out.The performance of the double rotor hub motor was tested and analyzed.The steady-state operating characteristics of the double rotor hub motor's variable voltage charging under different charging pressures were studied.The dynamic characteristics test of the variable voltage charging regenerative braking of the double rotor hub motor was carried out to verify the feasibility of the proposed double rotor hub motor variable voltage charging regenerative braking scheme.A double rotor hub motor and hydraulic ABS coordinated anti-lock braking test was carried out to verify the effectiveness of the proposed double rotor hub motor and hydraulic ABS coordinated control strategy. |
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