New sensorless commutation technique for brushless DC motors

摘要: In brushless DC (BLDC) drives commutation is performed by power electronic devices forming part of an inverter bridge. Switching the has to be synchronised with rotor position. Determination position, or without sensors essential requirement. The most common sensorless method based on detection zero crossings back EMF signals. This technique works only above a certain speed. BLDC systems which rely solely signals for suffer from relatively poor starting performance characterised rotation up one hundred and eighty electrical degrees fluctuations in electromagnetic torque. aim this project been investigate possibility cost effective but at start-up comparable that obtained when Hall are used. Initial investigations led saliency method. Theoretical analysis presented shows insensitive variations operational parameters such as load current speed circuit device voltage drops winding resistances. Also strategy, relying related measurements, proposed offers good sensor techniques.