Analysis of the motor driving a propeller of high altitude airship

Based on the concept configuration of the high altitude airship, electric motors were used to drive the propellers to generate thrust, however no detailed analysis on the motors was presented in the previous literatures. In this paper, the crucial problems were analyzed when the electric motors are applied for a propeller driving the high altitude airships. The main power generated by the solar array and the fuel cells equipped in the airship is in DC form, in addition, the high efficiency, high power/weight ratio and easy modulating speed-torque characteristics are demanded. Therefore the better choice for driving the propeller of high altitude airship is the rare earth permanent magnet brushless motor rather than the AC motor. In order to drive the propeller in a wide aerodynamic operational range, how to determine the rating parameters of rare earth permanent magnet brushless motors was studied. Further more, the part material selection, the bearings lubricant and the temperature rise were discussed. The experimental results showed that the rare earth permanent magnet brushless motor prototype could meet the requirement of a propeller and reached high efficiency.