13.21.1 Six-Step Sensorless Motor Control

Many control algorithms can be implemented using the dsPIC33CDVL256MC506 devices with the internal MOSFET Gate Driver.

The following information provides a starting point for implementing a 3-phase sensorless motor control application. The motor is driven by energizing two windings at a time and sequencing the windings in a six-step per electrical revolution method. This method leaves one winding unenergized at all times. The voltage (Back EMF or BEMF) on that unenergized winding can be monitored to determine the rotor position.