Pole Number Optimization and Closed Loop Control of an Outer Rotor BLDC Motor for UAV Application

This paper describes the performance study and design optimization of a medium speed antigravity type brushless DC (BLDC) motor featuring an outer rotor configuration. This motor is commonly employed in unmanned aerial vehicle (UAV) applications, with a particular focus on agricultural drones. The pole number optimization technique is used for such motors to lower the cost by reducing the number of permanent magnets needed while simultaneously increasing the efficiency. The present analysis uses the ratings and design specifications of a typical antigravity-type outer rotor BLDC motor employed in UAVs as a baseline. The design is optimized to achieve the highest efficiency with reduced magnet costs without compromising the performance. All the electromagnetic performance and structural analysis of the finally designed motor is verified in finite element method (FEM)-based simulation software. Following this, a closed loop control algorithm is presented to show the overall performance of the motor drive in MATLAB (Simulink) software.