A Novel Buck-boost Converter and Its Control Strategy for New Energy Power Generation.

To solve the problem that the output voltage of the new energy power generation device varied greatly and it was difficult to realize energy storage, a novel single-switch coupled buck-boost converter based on PI controller and feed-forward control was presented. The voltage gain could be adjusted by the turns ratio of the coupled inductor, and the voltage stress on the power switch was suppressed by the passive clamped circuit with recycled leakage inductor energy. Compared with traditional buck-boost converter, the proposed converter had the advantages of wider voltage conversion ratio, continuous input current, and low voltage stress on power switch. Combing PI controller with feedforward control strategy, superior input transient response of the converter during the whole input volt age range is obtained. The operating principles and steady-state characteristics of proposed converter were analyzed and derived in detail, respectively, and the performances were compared with other single-tube buck-boost converters. The small-signal model was derived, and the correctness of PI parameter design was verified by bode diagram. The design process of PI controller combined with feedforward control strategy was analyzed. Finally, an experimental prototype with a rated power of 100 W, 20 V to 60 V input, and 48 V output was built to verify the performance of the proposed converter in boost mode and buck mode, and the feasibility of PI controller combined with feed-forward control strategy. The measured maximum efficiencies with the boost and buck modes were 97.08% and 97.10%, respectively. [ABSTRACT FROM AUTHOR]