Zero Input Current Ripple LLC Resonant Converter with Integrated Interleaved Boost Converter

To improve the power generation efficiency and lifespan of photovoltaic and fuel cells, a two-phase interleaved boost integrated LLC resonant converter (IBI-LLC), which can achieve zero input current ripple, is studied in this paper. The IBI-LLC converter is derived by the integration of two stage converters, the first stage is an interleaved boost converter, and the second stage is a full-bridge LLC resonant converter. Only a pair of inductors and a bus capacitor are added to the full-bridge LLC resonant converter after the integration. For the IBI-LLC converter, the zero-voltage switching (ZVS) characteristic, as well as the zero input current ripple, can be achieved by employing pulse frequency modulation (PFM) control. Due to these features, the IBI-LLC converter is an excellent choice for applications where high voltage gain and low input current ripple are required. The detailed operating principle and characteristics with PFM control is analysed and the correctness of the theoretical analysis is finally verified by prototype experimental results.