Scheme based on buck‐converter with three‐phase H‐bridge combinations for high‐speed BLDC motors in aerospace applications

Abstract

High reliability and safety are critical in aerospace applications. This study introduces a novel high‐reliable inverter scheme based on buck‐converter with three‐phase H‐bridge combinations and a high‐accurate commutation instant shift correction method for high‐speed brushless direct current (BLDC) motors. First, the traditional three‐phase inverter and buck‐converter‐based BLDC motor drive system are analysed. Second, the zero‐crossing points of back‐electromotive force detection circuit are designed and the position detection error is analysed. Third, a speed measurement with enhanced detection frequency and accuracy is proposed. Then, a fast two‐stage commutation instant shift compensation method is designed based on the unique speed measurement method. High‐reliable and accurate commutations are achieved especially in the high‐speed steady state, which improves the speed control precision and decreases the motor driving loss. Finally, the control system design process is proposed and a fault‐tolerant‐control strategy is presented to enhance the reliability of the system. Experimental results illustrate the effectiveness and practicability of the proposed inverter scheme and the position sensorless control method.