Sensorless BLDC Motor Drive Based On The Line voltage

A sensorless control method for Brushless Direct current (BLDC) motor based on stator line to line back electro-motive force (EMF) is developed in this paper. To get information about necessary commutation signals, the difference of stator line to line voltages are used. The commutation point is achieved precisely at the same instant when the difference of back EMFs of the line voltages equals zero. This method needs no additional delay circuit (which is used in phase back EMF zero-cross detection method) and involves less calculation burden. The mathematical analysis, simulation results and the comparable experimental results have been shown to validate the effectiveness of the proposed sensorless drive operation.