~现有正激变换器磁复位技术旨在通过附加电路实现励磁能量转移，但其存在功能单一，能量传输机理不清晰，以及未能充分发挥励磁能量效用等问题。因此，提出一种副边附加LCD正激变换器，并研究其能量传输机理以及能量传输过程对变换器电气性能的影响，对实现高性能正激变换器具有重要的参考价值。
对副边附加LCD正激变换器的基本工作原理进行详细分析，同时根据励磁电感、正激电感及附加电感电流是否连续，将变换器划分为8种组合工作模式。通过对正激电感CCM时的组合工作模式进行分析，指出励磁电感既可工作于DCM，也可工作于CCM，且二极管D4可避免输出能量倒灌。探究了副边附加LCD正激变换器工作模式对电气性能的影响，综合得出有利于实现变换器高效率和大功率输出的最佳组合工作模式。通过对其能量传输机理进行深入研究，指出在正激期间，附加电容和附加电感进行能量交换，使附加电容上电压极性为左正右负，可为开关管低电压关断创造条件；在反激期间，通过对附加电容的储能释放过程研究，得出励磁能量可通过附加LCD电路传输到负载侧，且附加电容耦合到原边绕组的上正下负电压可实现开关管低电压关断。通过对能量传输特性深入分析，推导得出了传输到负载侧的漏感能量与原边产生漏感能量之比。此外，结合最佳组合工作模式下的能量传输机理，提出了确保变换器工作在最佳组合工作模式的附加电容、附加电感和正激电感参数优化设计方法。
根据技术指标，研制出一台480W的实验样机，通过波形测试对理论分析进行了实验验证，结果表明：励磁能量和部分漏感能量传输到了负载侧，且开关管具有低电压关断性能，同时，所研制的样机能够满足给定的电气性能指标要求。

~The existing magnetic reset technology of forward converter aims to realize excitation energy transfer through additional circuit, but it has some problems, such as single function, unclear energy transmission mechanism, and failure to give full play to the utility of excitation energy. Therefore, a secondary side attached LCD forward converter is proposed, and its energy transmission mechanism and the influence of energy transmission process on the electrical performance of the converter are studied, which has important reference value for the realization of high-performance forward converter.
The basic working principle of the secondary side additional LCD forward converter is analyzed in detail. At the same time, the converter is divided into 8 combined working modes according to whether the excitation inductance, forward inductance and additional inductance current are continuous. By analyzing the combined working mode of the forward inductor CCM, it is pointed out that the excitation inductor can work in both DCM and CCM, and the diode D4 can avoid the backflow of output energy. The influence of the working mode of the secondary side LCD forward converter on the electrical performance is explored, and the best combined working mode for realizing the high efficiency and high power output of the converter is obtained. Through the in-depth study of its energy transmission mechanism, it is pointed out that during the forward excitation period, the additional capacitor and the additional inductor exchange energy, so that the voltage polarity on the additional capacitor is left positive and right negative, which can create conditions for low-voltage switching off of the switch; During the flyback period, by studying the energy storage and release process of the additional capacitor, it is concluded that the excitation energy can be transmitted to the load side through the additional LCD circuit, and the additional capacitor can be coupled to the upper positive and lower negative voltage of the primary winding to realize the low-voltage shutdown of the switch. By analyzing the energy transmission characteristics, the ratio of the leakage inductance energy transmitted to the load side to the leakage inductance energy generated at the primary side is derived. In addition, combined with the energy transmission mechanism in the optimal combination mode, the parameter optimization design method of additional capacitance, additional inductance and forward inductance is proposed to ensure that the converter operates in the optimal combination mode.
According to the technical indicators, a 480W experimental prototype is developed, and the theoretical analysis is verified by the waveform test. The results show that the excitation energy and part of the leakage inductance energy are transmitted to the load side, and the switch has low-voltage switching performance. At the same time, the developed prototype can meet the given electrical performance requirements.

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