SOGI-FLL-2DOF PID—A Combined Second-Order-Generalized-Integrator-Based FLL and Two-Degree-of-Freedom PID Current Control for Switched Reluctance Motor Drives

This research article presents a current control technique aimed at reducing torque ripple in switched reluctance motors (SRMs). The current control strategy combines a second-order-generalized-integrator (SOGI) that utilizes a frequency-locked-loop (FLL) controller, together with a two-degrees-of-freedom (2DOF) proportional-integral-derivative (PID) controller. To mitigate the presence of current harmonic components, a parallel configuration is employed, wherein a SOGI-based FLL current controller is incorporated alongside the conventional PI controller. Nevertheless, the implementation of harmonics suppression in the SOGI-FLL controller may lead to an excessive amplitude in the current loop response. The implementation of a two-degree-of-freedom proportional-integral-derivative (2DOF-PID) controller aims to mitigate overshoot. This study examines four distinct controllers employed in SRMs, each possessing unique advantages and disadvantages in terms of mitigating torque ripple at various speed levels, enhancing output torque power, and maintaining decreased overshoots throughout a broad speed range. The current controller under consideration exhibits reduced levels of overshoot, torque ripple, and current harmonics in comparison to the aforementioned controllers. This study presents an analysis of the robustness of the SOGI-FLL-2DOF PID current controller for an SRM in both steady-state and transient-state conditions. The analysis is conducted using a combination of simulation and experimental results for 1 h.p., 1500 r/min, 6/4 SRM.