Simple starting-up method of BLDC sensorless control system for vehicle fuel pump

This paper proposes a simple starting method to align the rotor position of the brushless DC motor (BLDC) and accelerate the rotor from a standstill up to a given speed where the position sensorless control algorithm based on the back electromotive force (back-emf) can be properly applied. Both the stator current and the time period for alignment of the rotor position can be easily adjusted by modulating the pulse width of switching devices. The additional current sensor and any information of motor parameters are not necessary at start-up operation. Some experiments are implemented on a single chip DSP controller to demonstrate the feasibility of the suggested starting-up technique.