A Wide Input Range Isolated Interleaved Quasi-Z-Source Converter for Turbulent Renewable Energy Sources

Abstract

A review of existing modular interleaved converters for turbulent renewable energy sources including wind and solar power shows that with a small change in environment factors such as wind speed and light intensity, there is a much greater change in the power generation at the supply. Existing topolo gies largely discuss the use of static defined modular interleaved topologies, where the relation between the input and output of each interleaved module remains constant. This means that the conversion from the unstable input supply to a stable reliable output requires large passive components with an a similar variation in the duty cycle. In this thesis, we discuss the advan tages of different modular configurations including the Input Series Output Series (ISOS), Input Series Output Parallel (ISOP), Input Parallel Output Series (IPOS) and Input Parallel Output Parallel (IPOP). We then compare existing techniques for power conversion and how each of the modular con figurations perform with these systems. We then propose a control scheme to dynamically change between the configurations to best achieve their respec tive advantages. This helps reduce the size of the passive circuit components; the capacitors and inductors, by reducing the current and voltage stress on each component. The control scheme also reduces the control effort required by the active components e.g. the switches. Specifically, the Quasi-Z Source converter is interleaved due to its superior applicability over conventional ii iii converters. The use of Quasi-Z Source modules further simplifies the control strategy, reduces source stress with lower passive component ratings. It also requires a reduced number of the active components to operate which further increases efficiency. The simulation is perform on MATLAB Simulink using a turbulent input supply to verify the effectiveness of the proposed converter and the results are then displayed.