Active-Flux-Based Motion-Sensorless Vector Control of Biaxial Excitation Generator/Motor for Automobiles

This paper proposes an active-flux-based motion-sensorless vector-control structure for biaxial excitation generator for automobiles (BEGA) for wide speed-range operation. BEGA is a hybrid-excited synchronous machine having permanent magnets on q-axis and a dc excitation on d-axis. Using the active-flux concept, the estimated rotor position is given by the sum of the active-flux position and torque angle. The active flux is calculated by subtracting the term L_qi̅_s from the estimated stator-flux vector. The experimental results validate the active-flux principle and show good performance for a speed range of 50-2000 r/min. A method for initial rotor position of BEGA is proposed based on injection of a very short voltage pulse in the machine dc excitation, the method being independent of machine parameters. Experimental results for initial rotor-position estimation proved an accuracy below ten electrical degrees in less than 2-ms test time.