Research On Permanent Magnet Brushless DC Motor Control System For Range Extender Using In Electric Vehicle

The range extender can effectively extend the electric vehicle mileage and solve the shortage of battery charging pile and long charging time bottleneck which restricting the development of electric vehicles in the current and future for a long period of time.It can realize the smooth transition of the automotive industry from the fuel to electric mode.Therefore,the key components of the range extender,the motor control system has become a research hotspot in the field of electric vehicles.Permanent magnet brushless DC motor has become an ideal choice for electric vehicles increase drive motor because of the advantages of small volume,high efficiency,good reliability.In this paper,the electric operation,power generation operation,starting / generating process and non position sensor technology of the direct torque control system of permanent magnet brushless DC motor(DTC)for range extender with integrated starter / generator function is studied comprehensively.The particularity of direct torque control technology of permanent magnet brushless DC motor is analyzed deeply.The optimal voltage vector selection table of conduction phase is established.The method of rotor magnetic field division based on Holzer position signal is analyzed.The method of torque measurement based on phase current shape function and Holzer position signal is proposed.The realization of direct torque control system of Brushless DC motor using simple and inexpensive Holzer position sensor is solved.The simulation model of direct torque control system of permanent magnet brushless DC motor is established and simulation analysis and experimental study are carried out.The simulation and experimental results show that the direct torque control system of Brushless DC motor based on Holzer position signal has good static and dynamic performance.In this paper,the torque ripple suppression technology of the direct torque control system of the permanent magnet brushless DC motor is studied.A scheme to reduce the commutation torque ripple by using the overlapping commutation DTC is proposed.The DTC voltage vector selection table with overlapping phase change is established.The feasibility of overlapping commutation DTC scheme for solving torque ripple is verified by experiments.The experimental results show that the proposed DTC overlapping commutation scheme can effectively reduce the commutation torque ripple,and can greatly improve the static performance of Brushless DC motorThe generator system and the starter/generator conversion process of permanent magnet brushless DC motor using DTC are studied.The theoretical basis of the direct torque control technology to improve the dynamic performance of permanent magnet brushless DC motor generation system is derived.The structure of DTC permanent magnet brushless DC motor is designed,and the simulation model is built.For three phase asymmetric converter of permanent magnet brushless motor.,the modeling method of PSB and Simulink double three phase bridge is proposed,which solves the problem of the energy flow of the three-phase bridge and the calculation of the winding terminal voltage in the simulation model.The control process of starter/generator system is analyzed,and the conversion method from start to power mode is put forward.The simulation results and the experimental results prove the feasibility and high performance of direct torque control technology of permanent magnet brushless DC motor starter/generator system.The sensorless direct torque control of permanent magnet brushless DC motor is analyzed.A method of torque measurement based on the output signal of Position detecting circuit without position sensor is proposed.The scheme of sensorless direct torque control is given.The hardware and software design and implementation process of the direct torque control starter/generator system is introduced in detail.