Active-flux based motion sensorless vector control of biaxial excitation generator/motor for automobiles (BEGA)

This paper proposes a novel, 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 angle and torque angle. The active flux is calculated by subtracting the term L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</sub> i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> from the estimated stator flux vector. The experimental results validate the active flux-principle and show good performance for a speed range of 50 to 2000 rpm. 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 independency of machine parameters. Experimental results for initial rotor position estimation proved accuracy below 10 electrical degrees in less than 2 ms test time.