Sensorless Combined Control of In-wheel BLAC Motors for Mobility Scooter

Abstract

This paper presents a speed control for in-wheel brushless AC (BLAC) motors using a simple hall sensor to improve steering and driving performance of mobility scooters. To achieve smooth steering and motion controls, the sensor-sensorless combined estimation method is proposed. Furthermore, a modified current model reference adaptive system (MRAS) is also proposed to increase the dynamic response and estimation accuracy. The dead-time effect is directly compensated to improve the sensorless performance in the lower speed region. From standstill to the controllable minimum speed region, fast open-loop control method is applied to the traction motors. The vehicle velocity is then controlled using the speed information obtained from the proposed sensorless-sensor combined estimation scheme. To verify the effectiveness, a prototype mobility scooter was manufactured and the proposed control method was tested. Experiment results shows that the steering and motion of the vehicle are improved and the overall performance is increased compared to that of the conventional driving method.