Double H-bridge interleaved LLC converter with wide charging range and low output voltage ripples

This paper proposes a double half-bridge Interleaved LLC resonant converter with wide charging range and low output voltage ripples for dc-dc stage of electrical vehicle battery charger. The proposed converter consists of two parallel half-bridge LLC converters and has dual operating mode; combined and Independent. In the prior mode, both half-bridge converters operate simultaneously but in the later mode, single converter operates. Proposed interleaved converter has the ability to achieve wide output voltage using 180° phase shift between two switches of both half-bridge converters while using 90° phase shifted gate pulses of both converters in combined mode. By adapting this technique, output voltage ripples reduce drastically. When compared to the latter option, the former method produces a gain that is twice as great. The result is a broader output volta ge range when mode change and frequency control are coupled. The results demonstrate that when operated in combined mode with straightforward frequency control, the converter produces a broad 100-420 V output voltage range. The output range extends to 50-420 V thanks to dual frequency and mode shifting control. The proposed method reduces output voltage ripples which increases the quality of charging voltage to enhance the battery life span.