A Doubly Salient Starter/Generator With Two-Section Twisted-Rotor Structure for Potential Future Aerospace Application

The starter/generator is one key technology for the more electric/all electric aircraft. The wound-field doubly salient starter/generator supplies good prospect in the aircraft application. The doubly salient starter/generator prototype is modeled for simulation. The electromotive force (EMF) waveforms obtained from simulation are validated by the experiments. Based on the EMF waveforms of the machine, the standard three-step control algorithm is derived. When the rotor runs at high speed, the advanced angle control (AAC) method is adopted to get enough torque. The simulation and experiment results with two different control strategies are compared. The AAC scheme can increase the average torque by 62.7% at 3600 r/min. To reduce the torque ripples, the two-section twisted-rotor structure is adopted. The analysis shows that the two-section twisted-rotor structure helps to reduce the torque ripple coefficient by more than 50%. The two-section twisted-rotor structure is also helpful to reduce the output dc voltage ripple.

I. Introduction

The more electric aircraft (MEA) aims to replace hydraulic, pneumatic, and gearbox-driven subsystems with electrically driven subsystems to optimize the performance and life cycle cost. Therefore, the MEA claims advantages in reliability, maintainability, and energy efficiency [1]–[3]. Boeing's 787 Dreamliner and Airbus’ A380 are both successful examples where the more electric technologies have been adopted [3]–[5]. A starter/generator realizes engine starting and electrical power generation. Furthermore, it is a key technology to achieve a more electric/all electric aircraft. The variable frequency starter/generator is employed on the Boeing 787 airplane. The permanent magnet (PM) machine and the switched reluctance (SR) ones are thought as the competitive starter/generator [1], [3], [7]–[12].