Novel High Step-Up DC–DC Converter With an Active Coupled-Inductor Network for a Sustainable Energy System

In this letter, a novel high step-up dc-dc converter with an active coupled-inductor network is presented for a sustainable energy system. The proposed converter contains two coupled inductors which can be integrated into one magnetic core and two switches. The primary sides of coupled inductors are charged in parallel by the input source, and both the coupled inductors are discharged in series with the input source to achieve the high step-up voltage gain with appropriate duty ratio, respectively. In addition, the passive lossless clamped circuit not only recycles leakage energies of the coupled inductor to improve efficiency but also alleviates large voltage spike to limit the voltage stresses of the main switches. The reverse-recovery problem of the output diode is also alleviated by the leakage inductor and the lower part count is needed; therefore, the power conversion efficiency can be further upgraded. This letter shows the key waveforms of the proposed converter and the detailed derivation of the steady-state operation principle. The voltage conversion ratio, the effect of the leakage inductance and the parasitic parameters on the voltage gain are discussed. The voltage stress and current stress on the power devices are illustrated and the comparisons between the proposed converter and other converters are given. Finally, a prototype circuit rated 200-W output power is implemented in the laboratory, and the experimental results show the satisfactory agreement with the theoretical analysis.