High step-up isolated DC-DC converter with multi-cell diode-capacitor network

The existing high step-up DC-DC converters with multi-cell diode-capacitor network have large inrush current issue and strict LC filter requirement which are not suitable to achieve both high efficiency and high power density in relatively low switching frequency and large power application. In order to meet high step-up voltage regulation and compulsory electrical isolation due to public safety, this paper proposes a single-switch isolated DC-DC converter which exploits the features of multi-winding transformer and diode-capacitor voltage boost cell. The new topology has the following advantages 1). increase voltage boost capability and avoid extreme large duty ratio. 2) achieve almost zero output voltage ripples which reducing the inductance in output LC filter, 3) reduce transformer turns ratio and magnetic component volume. Furthermore, it can use the transformer leakage inductor and auxiliary switch to achieve zero-voltage switching (ZVS), which is beneficial to reduce the switching loss and increase efficiency.