Back EMF-Based Sensorless Control of BLDCM

Because of the high reliability and strong anti-interference capability under sensorless control, BLDCM is more and more popular. This paper describes the principles of back EMF-based BLDCM sensorless control, discusses the five kinds of rotor position detection methods in detail: terminal voltage detection, EMF integration, third harmonic of back EMF, freewheeling diode and line EMF, finally analyzes the advantages and disadvantages of each method. The paper is good for the design of the BLDCM sensorless control systems.