An Improved LLC Topology with High Fault Tolerance Ability

LLC resonant converters are widely used in various fields due to high power density and high efficiency. However, when a switch failure happens in LLC, the converter is unable to maintain the normal output voltage gain while achieving high efficiency at resonant point. To make it more compatible with fault occasion, this paper proposes an improved LLC topology that ensures the output voltage remains unaffected when a primary switch failure occurs. Moreover, it can operate near the resonant point, maintaining a high level of efficiency. Additionally, an optimized burst control is added to effectively suppress the overvoltage and oscillation of the resonant capacitor during the fault tolerance transition. Simulation verifies the effectiveness of the proposed method.