Derivation Analysis and Control of Multiport Flyback Converter with Lyapunov Function-Based Controller in Renewable Energy Systems Considering Circuit Parasitics

This paper addresses the analytical modeling of multiport flyback converters, which are governed by linear differential–algebraic equations. The modeling of these converters poses a challenge due to the switching between multiple such equations that govern the circuit’s behavior. The study emphasizes the importance of robust control strategies for addressing the non-idealities in flyback converters. Using MATLAB/Simulink, a dynamic model of the converter is developed. A comparison is made between a Lyapunov function-based controller, a linear proportional integrator controller, and an integral sliding mode controller. The controller consists of two main parts: a duty-ratio feedforward control unit for steady-state parameters and a Lyapunov function-based feedback control unit to handle disturbances. The feedforward control signal helps reduce the workload on the Lyapunov feedback controller. This control system ensures global exponential stability of the closed-loop system, enabling a swift transient response even under line and load disturbances. Mathematical simulations demonstrate its superior performance and stability, while experimental validations are conducted considering equivalent series resistances of each component. The proposed model and control scheme are further validated through a hardware prototype tested under various load and line disturbances. This research highlights the necessity of stress testing and performance evaluation for ensuring smooth and efficient operation of controlled multiport flyback converters across diverse conditions.