Sensorless permanent magnet AC motor drive with near zero-speed operation for electric-assisted bicycle

This paper presents a high performance electric-assisted bicycle system, where the rotor position is obtained by a position estimation technique using terminal quantities of the motor, which has a capability of starting from standstill. The components of the drive system include a wireless torque feedback, an application specific reference torque generation and torque control. The paper explains the implementation details of the position estimation technique that utilize a motor control DSP and provides real time test results to demonstrate its capabilities under real riding conditions including regenerative braking