【摘要】 在储能、电解、制氢等领域应用的电源，具有输出电压调节范围极宽、输出电流大等特点。通过检测整流管上的电压或电流的常规同步整流技术不仅大幅度提高了系统成本，而且会增加电路中寄生振荡，影响电路的安全稳定工作。为了获得宽的输出电压调节范围，具有效率优势的LLC拓扑需要工作在低于谐振频率、高于谐振频率和移相等多种工作模式。在不同的工作模式下，变压器副边整流管上的电压、电流波形与原边的电压、电流波形的相位关系有所不同，为同步整流控制信号的生成带来了困难。针对工作于多种模式的大功率低压LLC电源的效率提升，提出了一种基于原边功率开关管控制信号与谐振腔电流采样的同步整流控制方案。分析了不同模态下，副边整流管信号与原边开关管控制信号之间的关系，提出了一种同步整流控制策略，根据不同工作模式，基于原边桥功率开关管控制信号生成副边同步整流管的控制信号，为了避免低于谐振频率模式下在平台区时间发生误脉冲导致输出并联的环流，检测谐振腔电流消除误脉冲的产生。最后通过搭建实验样机进行了控制方案的验证。更多还原

【Abstract】 Power supplies used in energy storage, electrolysis, hydrogen production, and other fields have the characteristics of wide output voltage range and large output current. The conventional synchronous rectification technology that detects the voltage or current on the rectifier not only significantly increases the system cost, but also increases parasitic oscillations in the circuit, affecting the safe and stable operation of the circuit. In order to achieve a wide range of output voltage, LLC topologies with efficiency advantages need to operate in various working modes such as below resonance frequency, above resonance frequency, and phase-shift. Under different working modes, the phase relationship between the voltage and current waveforms on the secondary side rectifier of the transformer and the voltage and current waveforms on the primary side varies, which brings difficulties to the generation of synchronous rectification control signals. This article proposes a synchronous rectification control scheme based on the control signal of the primary power switch and the sampling of the resonant current to improve the efficiency of high-power low-voltage LLC power supplies operating in multiple modes. The paper theoretically analyzes the relationship between the signal of the secondary rectifier and the control signal of the primary switch under different modes, and proposes a synchronous rectification control strategy. Based on the control signal of the primary bridge power switch, the control signal of the secondary synchronous rectifier is generated according to different working modes. In order to avoid the occurrence of false pulses in the platform area time below the resonant frequency mode, which leads to output parallel circulation, the resonant current is detected to eliminate the generation of false pulses. Verified by building an experimental prototype.更多还原