Abstract The LLC converter plays a pivotal role in the infrastructure supporting electric vehicles, where efficiency and reliability are paramount. Its ability to efficiently transfer energy between different voltage levels makes it particularly suitable for EV charging stations, where power conversion efficiency directly impacts operational costs and environmental sustainability. Synchronous rectification has emerged as a promising strategy for optimizing LLC converter performance. By replacing traditional diode rectifiers with active switches that operate synchronously with the converter's switching frequency, synchronous rectification minimizes energy losses and improves overall efficiency. However, existing synchronous rectification methods have faced challenges, such as complex control algorithms, sensitivity to load variations, and the need for high-frequency sampling. Unlike conventional approaches that rely on high-frequency sampling for precise timing control, the novel synchronous rectification scheme utilizes a streamlined time-domain analysis. This approach dynamically adjusts the timing of the synchronous rectifier based on real-time feedback from the LLC converter's operating modes, ensuring optimal efficiency across a wide range of operating conditions with high-frequency sampling and alleviating the computational burden. By reducing the complexity of control algorithms and eliminating the need for high-frequency sampling circuits, the scheme not only lowers manufacturing costs but also enhances reliability by reducing potential points of failure. This simplification is particularly advantageous in high-power applications like EV charging stations, where robustness and operational uptime are essential. Simulation studies have validated the effectiveness of the proposed scheme under different load conditions and frequencies. Simulations have shown significant efficiency improvements compared to traditional methods, highlighting the scheme's potential to reduce energy losses and improve overall system performance. Furthermore, experimental validation using a 6.6 kW prototype shows that the proposed scheme delivers consistent and efficient operation under steady-state and dynamic conditions, further supporting its potential for commercial EV charging infrastructure integration. The adoption of the proposed synchronous rectification scheme promises to enhance the efficiency and reliability of LLC converters and accelerate the transition to electric mobility. As governments and industries worldwide prioritize sustainability goals and seek to reduce carbon footprints, improvements in energy conversion technologies play a crucial role in supporting the widespread adoption of electric vehicles. In conclusion, the synchronous rectification scheme represents a significant step in evolving LLC converters for electric vehicle charging infrastructure. By overcoming traditional limitations and leveraging streamlined control strategies, the scheme enhances performance and contributes to the sustainability of transportation systems. As research continues to refine and optimize power conversion technologies, the ongoing advancements in LLC converter designs underscore their pivotal role in shaping a cleaner, greener future for global transportation.
Zhang Yuxin,Chen Jie,Wang Jian等. Synchronous Rectifier on-Line Driving Strategy for LLC Resonant Converter Based on a Simplified Time Domain Model[J]. Transactions of China Electrotechnical Society, 2025, 40(8): 2615-2629.
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2025, Vol. 40 
