Research On Ramp Start Control Method Of Pure Electric Vehicle

With the rapid development of new technologies for electric vehicles and the guidance of national policies,electric vehicles have become the most popular research hotspots and concerns.As a part of the electric vehicle control technology,the ramp start control technology of electric vehicles is related to the safety and comfort of passengers.In recent years,it has become a hot topic for researchers.The focus and difficulty of its research lies in the control of the motor torque at the output end of the motor.The size of the motor output torque directly determines whether the electric vehicle ramp can start smoothly.This paper studies the starting control technology of electric vehicle ramp,controls the output torque of the motor,and formulates the starting control strategy of electric vehicle ramp to ensure the smooth starting of electric vehicle ramp.This paper mainly studies the following contents :The control characteristics of traditional fuel vehicles and electric vehicles in the process of power driving and starting are compared and analyzed,and the starting control is explained according to their characteristics;the principle of motor driving system for electric vehicles is analyzed,the vector control system model of permanent magnet synchronous motor is built,and the two different driving modes of torque control and speed control are analyzed;according to the characteristics of the power source of electric vehicles,the electric vehicle The starting is analyzed,and based on the analysis results,the standing torque to keep the vehicle stationary is calculated,and the vehicle adaptive torque regulation starting control schematic is given,and the control strategy is analyzed specifically.According to the proposed control strategy,the vehicle slope distance is used as the basis for evaluating whether the control strategy is effective and feasible.When the vehicle starts on the ramp,the magnitude of the ramp resistance depends on the vehicle mass and the slope.The extended Kalman filter algorithm is used to jointly estimate the vehicle mass and the road slope,and the simulation results show that the algorithm can effectively identify the vehicle mass and the road slope with small errors.By detecting the state parameters of the vehicle driving on the ramp and acquiring the driving conditions of the vehicle,the standing torque required to stabilize the electric vehicle on the ramp at this time is calculated according to the estimated vehicle mass and road slope;considering that the theoretical and actual values of the calculated standing torque have certain deviations due to the influence of vehicle parameters and road environment,a closed-loop motor zero speed regulation is added to dynamically adjust the output compensation The motor zero speed closed loop regulation is added to dynamically adjust the output compensation torque and control the vehicle to reduce the slope distance.When the driver presses the accelerator pedal to start,it will start according to the torque given by the driver.The simulation model of ramp start control strategy is built in Matlab,and the real vehicle environment is simulated by Carsim software and simulated jointly with Simulink.The simulation results are effective and feasible,and the motor output torque can be precisely controlled,and the smooth start of the vehicle on the ramp can be ensured under this control strategy.Then the experimental scheme of the control system was designed,the software and hardware system of the motor controller was designed,and the load simulation device was loaded to simulate the ramp starting conditions.A 2 kW silicon carbide(SiC)discrete hybrid device controller prototype was designed as its hardware platform,and the control algorithm was experimentally analyzed.