Design And Implementation Of In-wheel Motor Driving Electric Vehicle Distributed Control System

As the demand for environmental protection of the vehicle increases, the newenergy vehicles with new technologies and structures have become the trend of thewhole auto industry. In-wheel Driving EV uses motor to drive wheels, which changesthe structure of vehicle powertrain systems, and becomes frontier technology ofEV(Electric Vehicle). There are lots of challenging problems In-wheel Driving EV.The issue discussed in this paper is application-oriented, taking no account of In-wheel motor designed problems, only focusing on distributed control of In-wheelelectric drive system, thus two main problems are discussed in this paper: The schemeof In-wheel electric drive system’s FlexRay bus and the drive technology. Since In-wheel electric drive system proposed higher requirements for transmission rate and faulttolerance of communication, in this paper we design the system’s FlexRay bus first.The FlexRay bus protocol shows that the hardware design is based on physicallayer and network communication is based on link layer, network layer. To realize thecommunication in FlexRay, we designed physical layer and network layer in detail, andimplemented node’s wakeup startup, ultimately realized data send and receive betweennodes. According to the In-wheel electric driving system’s demand, we designedFlexRay bus application layer. By analyzing the functionality of master and slave node,we designed information between nodes for motor control. In order to improve thedynamic performance of FlexRay bus, we designed application layer scheduling bybuilting the system matrix and optimizing it.In the In-wheel electric drive system, due to the excellent properties, we selectPMSM as a hub motor. But the physical model of PMSM is complexity, so wesimplified it in the rotor coordinate system, and used i_d=0vector control methods tocontrol the motor. Considering the potential disruption, we found a sliding modecontroller through the design of sliding and sliding mode switching control law, andbuilt motor model under Matlab/Simulink. According to the simulation, we verify theperformance of SMC system.Next, we simplified the structure of In-wheel electric drive system, discussed two-wheel motor speed synchronization problems based on SMC. Firstly, we analyzed thedual-motor synchronous control strategy and verified by simulation results. Then, underMatlab/Simulink, we done simulation using synchronous compensator control strategy,accordingly built experimental platform of the system, achieved real-time control ofPMSM via FlexRay bus, verifed the correctness of the simulation.