An initial rotor position estimate technique on three-stage aviation brushless synchronous machines

Along with the fast development of more electric aircrafts (MEA) and all electric aircrafts (AEA), the three-stage aviation brushless synchronous machines are widely used, which adopt the brushless structure and combine the merits of high power density and adjustable magnetic fields at the same time. According to saliency of the main generator of three-stage brushless synchronous machines, the information of rotor position is implied in performances of stator inductances due to the magnetic saturation effect. This paper studied the variation of inductances then estimated the initial rotor position of main generators by injecting modulated pulse voltage vectors. The three-stage aviation brushless synchronous machines are excited by single-phase AC during the starting period. The excitation current of the main generator contains severe pulsating components, thus the traditional methods can not accurately locate the initial position angle of the rotor. An initial rotor position estimation method in which Fourier analysis method was adopted to analysis the response currents was proposed, based on the analyze of the output characteristics of the exciter and the research of the integration model considering the exciter and the main generator in the starting period. The experimental results show that the proposed method can exclude the pulsation of exciter currents, therefore an initial rotor position angle is gained more reliably and efficiently.