Dynamic Performance Improvement of Diode-capacitor-Based High Step-up DC-DC Converter Through Right-Half-Plane Zero Elimination

Diode-capacitor-based dc-dc converters provide a simple and low cost solution for high step-up voltage regulation in solar and fuel cell generation. Transient modeling analysis reveals their worse influence of nonlinear and nonminimum-phase system characteristic due to right-half-plane (RHP) zero, especially in high voltage gain application. However, the process of energy transfer for diode-capacitor-based dc-dc converter is different from basic dc-dc converter. Based on the unique feature, this paper proposes an improved main circuit structure with parallel connection of resistive-capacitive damping network across the intermediate capacitor to achieve good dynamic performance. By optimal parameter design according to Routh-Hurtwitz criterion, all the RHP zeros in the transfer function of control-to-output voltage are eliminated completely. Then, by the case of diode-capacitor-based boost converter, the adaptive PI controller is designed to deal with nonlinear characteristic of voltage gain. It gets good dynamic performance under wide range output voltage. All the theoretical findings and design approaches are verified by simulation and experiment results. The existing diode-capacitor-based high step-up dc-dc converters with slight main circuit modification are more promising in renewable energy application.