RESEARCH ON THE SENSORLESS STARTING CONTROL METHOD OF UAV STARTOR/GENERATOR

Brushless DC motor (BLDC) is mostly used in UAVs and the load is a piston engine with changing torque. The traditional "three-stage" sensorless control method is prone to failure under variable load. In this paper, under the MATLAB/Simulink environment, the simulation model of BLDC starting control system was established, the mathematical relationship among phase current, reverse electromotive force, electromagnetic torque, load curve and speed was compared and analyzed. Finally, the reason why the traditional "three-stage" control method is easy to fail under the variable load environment is explained from the mechanism level. Then a compound "three-stage" starting control strategy is proposed, and the simulation model of the control strategy is built in MATLAB/Simulink environment. The simulation results show that the starting performance of the strategy under variable load environment is obviously better than the traditional "three-stage" control method.