Optimized virtual impedance solar restoration droop emulated SEPIC controller under low irradiation

Abstract

This paper is focused on PV-based reduced order pade’s approximation SEPIC virtual impedance, restoration controller with parallel impedance emulation condition. However, the complexity of the higher-order SEPIC controller has been reduced and compared by Pade’s approximation with different reduction techniques. It covers the time response, oscillation, overshoot, dynamic performance and stability of the controller. The computational time and need of the sensor are less and occur better response compared to the other reduction technique under the solar irradiance variation. However, in PV, the dynamic resistance is generalized by nonlinear solar I-V curve dependent on the operating point as irradiance, temperature and its I-V curve. The non-linearity effect affectsthe stability of the system. TheSEPIC outer voltage and inner current controller with virtual impedance controller is used to enhance the stability, and comparative response demonstrated through the bode plot. A virtual impedance controller (VIC) cascaded with voltage restoration is used to minimize the voltage notching and oscillations under variation of inertia coefficients. The transient and dynamic performance of reduced order using a genetic algorithm controller has been used to demonstrate and discuss the PV-SEPIC system's stability.