Research Of Electric Hydraulic Power Steering System Motor Controller On Electric Passenger Car

The Electric bus has become the focus of attention due to its energy saving and no pollution. Because of the large electric bus have great weight, long running time and higher safety coefficient features, seek the aid of a safe, reliable and energy saving system has become the key to the development of the electric bus. The motor of Electro-hydraulic power steering (EHPS) system driven the hydraulic pump of hydraulic system to provide the steering, The control system based on vehicle speed and the input torque to the steering wheel to judge the real-time changed the provided power size, to let the car have low speed which is portability and high-speed stability.By analyze the electro-hydraulic power steering system structure and working principle, This pater design the linear dynamical characteristics curve to meet the driver’s steering portability and stability. In order to guarantee the drive motor can provide rapid and stability response, based on the analysis of system related mathematical model of hydraulic components and asynchronous motor, use closed-loop vector control strategy, make the motor speed can quickly achieve the stable value, and does not vary with load torque fluctuation change, not only satisfy the power size needed for the driver, and can make the accurate information about the access road.Through analyzing the dynamics of electric hydraulic power steering system, the hydraulic system parts and mechanical parts of the model was established in the AMESim software. The motor vector control part and the power curve model was established in Simulink. Through the combination of the two simulation software, observe the output dynamical of the power hydraulic cylinder along with the change of the speed and steering wheel input torque. Based on the construction of the hardware and software platform, the asynchronous motor no-load test and loading test system have been done. The Simulation and experimental results show that:this paper uses the asynchronous motor vector control strategy can guarantee the automobile steering portability and road feel, the speed of the motor can vary with system need to change in a timely manner, and have a smooth output torque, to ensure the driver’s road feel. With the increase of the rotational speed of the motor output torque of the motor, can meet the demand of electric hydraulic power steering system to the controller.