Performance analysis of high-frequency isolated dual half-bridge three-level bi-directional DC/DC converter

A novel topology of high-frequency isolated dual three-level half-bridge bidirectional DC/DC converter is discussed, which is very suitable for the medium or high voltage high power applications due to the effective reduction of voltage stress of the power switches. The working modes of the discussed topology under the dual phase-shifting control have been analyzed, the soft-switching condition and the characteristics of the backflow power have been derived while the converter is working on the condition of d<;1. In order to improve the whole system efficiency, an optimal control strategy has been proposed, and the corresponding algorithm is also designed to figure out the minimum primary backflow power point with the desired transmission power and soft-switching. In final, the experimental results were presented to validate the theoretical analysis and the feasibility of the proposed new optimal control strategy.