Position estimator for a brushless‐DC machine using core saturation and stator current slopes

Abstract

Purpose – This paper is devoted to the investigation of position estimation for a brushless DC machine using only their stator currents. The first application is for a hybrid electric vehicle, where the generator will be used as a motor to start the internal combustion engine (ICE).Design/methodology/approach – This paper describes how to estimate the rotor position of a brushless DC (BLDC). Two different strategies, both based on stator currents, will be used: one for low speeds to start the ICE, and one for normal speeds for future applications in a pure electric vehicle (EV). The first one uses an estimation method based on core saturation and the second one is based on the determination of the current slopes on two of the three phases. The algorithms proposed neither needs to measure any machine parameters, nor the back emf. The methods use the information contained in the current magnitudes and slopes, and the machine mechanical speed. The system was implemented using a Digital Signal Processor (TMS3...