Design Of A Permanent Magnet Synchronous Motor Drive System For A 5kW Electric Motorcycle

A practical solution to address the shortage of oil energy and severe road traffic load in first-tier cities in China is the development of electric motorcycles that meet the travel needs of the Chinese people.With the discovery of rare earth resources in China,Permanent Magnetic Synchronous Machine(PMSM)has gradually transitioned from aerospace and military use to civilian use.Their small size,lightweight and high efficiency make them an ideal choice for electric motorcycle drive systems.A controller is required for the PMSM drive system for electric motorcycles to control sufficient torque output from the motor during starting,acceleration,and uphill stages.A wide speed range is also required during high-speed driving.This thesis focuses on the PMSM drive system for electric motorcycles and compares different motor controller algorithms.The specific contents are summarized as follows:(1)A simulation model of the surface-mounted permanent magnet synchronous motor(SPMSM)FOC speed control system is constructed based on the basic theoretical knowledge of coordinate transformations.The control method used is Id = 0 control and PI controller.Simulation results show that poor disturbance rejection is a problem.An embedded permanent magnet synchronous motor(IPMSM)control system is constructed since electric motorcycles produce many load disturbances during driving,and the reluctance torque is not utilized.The speed loop controller is improved based on the exponential convergence law of sliding mode control(SMC),and a comparative study of Id = 0 control and maximum torque current ratio control(MTPA)is carried out.Experimental results show that MTPA control can coordinate the relationship between torque and current.They produce greater torque under the same current.At the same time,SMC improves the system’s disturbance resistance.(2)A new sliding mode controller based on weighted integral gain combined with MTPA in the exponential convergence law is proposed in this thesis.The original sign function is changed to a saturation function to increase disturbance resistance,and the motor reluctance torque is fully utilized.Simulation results show that when compared with traditional SMC when the output torque is the same,the proposed control method reduces the amplitude of the three-phase current by 1.15 A,reduces jitter by 35.02%,and reduces speed fluctuation after increasing load disturbances by 23.9rpm.(3)The software and hardware scheme of electric motorcycle is designed to realize the proposed new sliding mode controller in this thesis.It is divided into two parts: the application layer and the drive layer.Essential functions such as braking and torque control are implemented in the application layer.At the same time,a software and hardware requirement analysis is conducted,hardware schematics and main software processes are designed,and the newly proposed control system is used as the drive layer of the controller.The proposed control method increased the Peak power by 0.19 k W,and maximum torque was increased by an average of 1.84 Nm at each speed point.