Rotor Offset Angle Estimation and Field Oriented Control of Synchronous Reluctance Motor

The paper proposes method to precisely estimate the rotor offset angle arising due to improper or faulty mounting of the encoder wherein the encoder index slit and stator axis are not aligned for a Synchronous Reluctance Motor (SyRM) along with the implementation of Field Oriented Control (FOC) of the same. To calculate the offset angle between the stator axis and index pulse of the encoder, a DC excitation on the stator windings, resulting in a net flux directed along the required phase is provided. This leads to the alignment of the rotor with the established flux, traversing an angle, which when compared with the index pulse provides the offset angle of the rotor. Thereafter, Field Oriented Control of the motor has been explained in rated field operation. Experimental results of tests conducted on a 3.7 kilo-Watt laboratory prototype have been used to validate the proposed scheme.