Sensorless control of switched reluctance motor drive based on BEMF calculation

There have been several approaches to the problem of sensorless rotor position detection in switched reluctance motors but the great majority of them are not able to cover all the constant torque region in SRMs torque-speed profile since they are mainly based on voltage equation integration to estimate the flux or neglecting motional the back electromotive force or BEMF, in that equation. This paper proposes a method to the sensorless control of SRM to cover the specified region efficiently. A novel method to estimate the back EMF online based on the current waveform is introduced. A position estimation equation is derived based on the estimated BEMF and an analytical model for the SRM. Then a commutation strategy is designed based on the position estimation equation. The proposed sensorless method has been implemented on Texas Instrument TMS320LF2407 fixed-point digital signal processor and has been applied to a 1hp SRM test bed successfully