Design and Analysis of Reconfigurable Resonant Converter with Ultra Wide Output Voltage Range

In this article, a reconfigurable isolated dc/dc converter is proposed suitable for a wide output voltage range of 180-1500 V for efficient onshore charging in maritime applications. The proposed circuit concept can also fulfill the requirements of other heavy-duty battery charging applications, especially those operating within the shore environment - such as straddle carriers, forklifts, reach stackers, and terminal tractors. The circuit topology consists of two interleaved LLC resonant converters each connected to a three-winding transformer. Through the use of additional circuitry, the topology can be adapted to operate at peak efficiency in three output voltage ranges. Furthermore, the topology is able to alleviate the current and voltage stresses on the semiconductor devices in comparison to the conventionally employed LLC resonant converters. The operation of the circuit is explained and its steady-state model is developed. In order to validate the performance of the converter, an 11-kW prototype is designed, tested, and analyzed. The experimental results attest that the proposed reconfigurable resonant converter is able to achieve an extremely wide output voltage range while maintaining a high power transfer efficiency.