Two-stage photovoltaic system with a high-gain fifth-order boost converter

This paper introduces a novel two-stage PV system comprising a high-gain, efficient fifth-order boost converter. The dynamic modeling of the system components, including the PV array, fifth-order boost converter-based PV-side converter (FOBC-PVSC), grid-side converter (GSC), and grid is analyzed. The system’s dynamic and small-signal analyses are evaluated to determine how FOBC-PVSC input capacitor changes affect the system’s overall performance. The FOBC-PVSC’s eigenvalue and PV input-to-output transfer function analyses are used to determine the stability and allowable range of the DC-stage input capacitor values. The grid-side converter’s eigenvalue analysis evaluates the proposed model’s robustness to grid short-circuit ratio changes and band-pass filter damping ratio variations in grid voltage measurement. The grid-side LCL filter stability analysis is considered and different passive damping models evaluated to address resonance issues. Also, the proposed system’s MPPT and GSC controllers are modeled to obtain the maximum available PV power, boost the voltage to 800 DC volts, and convert the DC output to AC grid-rated value. • The proposed fifth-order boost converter-based PV model has higher efficiency, reduced ripple current, and better power-boosting capability at a lower duty ratio compared to conventional boost converters. • Dynamic and small-signal analysis were used to determine the system’s stability and allowable range of the DC-stage input capacitor values corresponding to stable, marginal, and unstable regions of operation. • Increasing the PV-side converter input capacitor value above the marginally stable value range increases the MPPT static and dynamic error, leading to voltage steady-state ripple and significant deviations in performance.