A Study on Sensorless Trapezoidal BLDC Motors Based on Back-EMF Zero Crossing Detection Method

This paper carries out a study on the use of back Electromotive Forces (EMF) zero crossing detection to obtain speed estimation on Brushless Direct Current (BLDC) motor. The study covers the control strategy, changeable speed input and gain changing on Proportional-Integral-Derivative (PID) speed controller. For that purpose, direct back-EMF detection method is used to obtain back-EMF value. This method compares the detected zero crossing with neutral point voltage. This method is re-studied because it is inexpensive and simple whether in its circuit implementation or equation algorithm.