A Sensorless Control for Brushless DC Motor Drives in Wide Rang of Speed Variations

This paper describes a brushless DC motor without a position sensor. The applied method uses a digital phase shifter for zero crossing and phase shifting, which its performance is independent of input frequency. The phase shifting is performed by digital integration which this feature effectively decreases noise effects. This approach makes it possible to detect rotor position in relatively wide range of speed variation. The fully digital solution lets to eliminate analogue parts. The applied method is simpler than previous methods and can minimize the size and cost of control board for low power motors. Experimental results using dSPACE real time simulation based on Texas Instrument DSP processor shows validity of the applied method. Also the applied phase shifter provides possibility for investigating the field-weakening technique for rectangular machines.

Keywords:

sensorless control , brushless DC motor , digital phase shifter , real-time simulation