A Composite Approach of Sensorless Rotor Position Sensing for Brushless DC Motor

摘要

The principles and characteristics of the sensorless brushless DC motor rotor position detection were analyzed by using inductive method and third harmonic back-EMF detection method.A composite rotor position detection method was proposed in full speed range (including zero speed).At zero speed (static state) inductive method was used to determine the initial rotor position,and it was bases of starting and controlling for the brushless DC motor; at low speed third harmonic back EMF detection method was used.Analysis shows that the composite test method can estimate the rotor position,and it is to achieve the position sensorless brushless DC motor to run a viable method.