A Comparative Study on Using Brushless DC Motor Six-Switch and Four-Switch Inverter for UAV Propulsion System

Electrical propulsion system using Brushless DC(BLDC) motors is widely used nowadays in mini Unmanned Aerial Vehicle (UAV), as it guarantees an efficient performance and long flight endurance enhancement. The driver of BLDC has a pivotal role in this electrical propulsion system. Three-phase inverter with six switches design is the most common in the driver model of a conventional BLDC motor. In this paper, a comparative study between the BLDC motor drive system using a non-ideal six-switch three-phase inverter (SSTPI), and a non-ideal four-switch three phase inverter (FSTPI) is investigated. The study point-of-view is the enhancement of the propulsion system efficiency, cost, and controllability. Mathematical models for the two proposed systems including BLDC motor are introduced. Simulation using MATLAB Simulink is performed at different flight modes with variable motor speeds. A comparative study declares the tradeoff choice between the two drive systems to enhance the system performance based on the preferred selection criterion. This study provides a good guide for designing such BLDC motor driver systems.