Performance and stability analysis of an electric scooter drive system

The performance and stability of Permanent Magnet Brushless Direct Current (PMBLDC) hub motor-drive system of electric scooter has been carried out in this study. The study involves development of motor-drive model with circuit-oriented system, its state space representation, and Simulink models. Simulation case study was performed to analyze the motor performances, and back e.m.f’s, current, torque, and rotor speed for various inclination. A stability analysis was developed for the electric scooter of 200 kg weight, driving at a speed of 30–40 km/h, including an inclination up to 20°, by incorporating 1.5 kW PMBLDC hub motor. The motor ratings chosen are in par with the ratings of the vehicle parameters, design and dynamics in order to obtain the best possible torque-speed profile. Experiments were conducted to validate the motor-drive model applicability to the variable road traffic and gradients. The simulation and experimental results on efficiency, torque and power agreed very well with each other. It has been observed that the developed PI controller technique is suitable for unit step response, transient and ramp conditions with high-speed control accuracy and good dynamic response which are of key importance for an electric scooter.