A novel rotor position detection method using morphological filter algorithm for brushless DC motor

In this paper, by analyzing the relationship between rotor position and phase back electromotive forces (PB-EMFs) of brushless DC motor (BLDCM), a novel rotor position detection method based on morphological filter algorithm (MFA) for BLDCM is proposed. MFA is applied to identify the signal turning points (STPs) of the input stator PB-EMFs, which provides technical support for the current commutations of PWM control system. In addition, accurate current commutation point detection of BLDCM promises rotor field to keep perpendicularity with armature magnetic field, to achieve accurate detection of rotor position and position sensorless control of BLDCM. Results of simulation studies proved that, the proposed detection method can realize the position sensorless control for BLDCM by obtaining the STPs of PB-EMFs in BLDCM, which greatly improves the static and dynamic performance of speed regulation system of BLDCM, and obtaining a outstanding control effect.