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

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.