Application of nonlinear control to switched reluctance motors: a feedback linearisation approach

The design of a feedback 1ine:irisation (FHL) controller for switched reluctance (SR) motor is presentsed. The mathematical iinodcl 01ʹ the motor takes magnetic saturation into accciunt. It has been shown through simulation studies that a FBL controller based on a linear contti-ol !aw provides better dynamic performance in comparison with a PI controller. However, the FBL controller based on a linear control law alone is not adequate to handle uncertainty in the SR motor model, and hence the corresponding torque ripple is substantial. To reduci: torque ripple in the drive system the design of a robust FBL controller based on Lyapunovʹs second method, which takes care of model uncertainly is presented. Out of the three input variables to the SR motor, phase voltage, on-angle and off-angle, the phase voltage is used as the mariipulated control variable in the drive system. Performance of the nonlinear model together with the robust FBL controller for a speed control application is examined through digital simulation. Simulation results obtained confirm reduction in torque ripple, improved transient and steady-state performance and robustness of the coni.roller to parameter varia lions under various lypes of disturbances.