Software position tuning of a SRM drive system

The paper presents a method for estimation of the initial position in a SRM drive which is provided with an incremental encoder. This is necessary immediately after power up, before the motor starts and the index signal is received. On the other hand, to calculate the rotor position when the motor runs the control system should know the displacement of the index signal from the reference position of one phase. It is a value not altered from the mounting of the encoder on the motor shaft and can be determined by a software routine presented here.