Author(s): B. Venkata Sai Prasad , K. Mahesh

The proposed paper is a modified LLC converter with two series transformers, which has four operation configurations, covering the range of four times the minimum input voltage. To optimize the proposed LLC converter in attempt to achieve good efficiency. In order to minimize the magnetizing current and thus minimize the conduction and core losses, an optimal objective is proposed to find the maximum magnetizing inductance. Optimization procedure is given. Two conventional LLC converters are designed using fundamental harmonic approximation (FHA) and the proposed optimal design respectively to make comparison with the proposed LLC converter and validate the proposed optimal design. Matlab results show the proposed converter with proposed optimal design can achieve the peak efficiency up to 99%, while maintaining a very wide input voltage range. Utilization of this LLC converter in transmission lines is also introduced.