MRAS disturbance observer-based sensorless field-oriented backstepping control of BLDC motor drive
Authors :- D Joshi, D Deb, AK Giri
Publication :- Electrical Engineering, Springer, 2024
Unmanned aerial vehicles (UAVs) powered by electricity are becoming increasingly popular for civil, military, and commercial applications. Accurately controlling the brushless direct current (BLDC) motor propeller system is necessary for UAVs to perform complex maneuvers in the air. A field-oriented backstepping control (FOBSC) is proposed for enhancing the speed control performance of the propeller motor drives as per the demand of the flight controller. The FOBSC is designed to minimize input control efforts and dynamically adopts various beneficial characteristics such as high tracking accuracy, quick convergence, and reduced chattering in control input of the BLDC motor propeller drive. For improved overall performance of the propeller motor drive under internal and external disturbances, especially wind gusts, the rotor speed-based MRAS disturbance observer (MRASDO) has been developed and integrated with FOBSC. An MRAS estimator based on stator current is developed to estimate real-time rotor position and speed, removing the need for physical sensors, which is more complex for UAV applications. The sensorless control algorithm adapts variations in stator resistance and rotor magnetic flux of the BLDC motor, which enhances performance and stability and provides information on temperature rise, motor fault detection, and stator/rotor condition monitoring. The closed-loop stability of the MRAS estimator, MRASDO, and FOBSC is carried out using the Lyapunov method to guarantee reliable operation under any operational conditions. Finally, comprehensive numerical and experimental tests demonstrate that the proposed sensorless FOBSC approach is superior to sliding mode control and classical PI control.