针对现有正激变换器磁复位技术功能单一，电路结构复杂及转换效率低的问题，提出了一种可实现多功能复用的副边LCD串联型正激变换器，在没有增加电路复杂性的同时提升了变换器的电气性能，对正激变换器的推广应用具有重要的指导意义。

通过对所提出变换器的工作原理和性能进行分析，指出附加LCD支路既可使磁芯复位，也可将励磁能量传输至负载侧，同时该变换器还可实现开关管低电压开通与续流二极管零电流关断。该变换器励磁电感、附加电感及正激电感均可工作于连续导电模式（Continous Conduction Mode, CCM）和不连续导电模式（Disontinous Conduction Mode, CCM），据此将变换器分为8种不同的组合工作模式，通过对各种组合工作模式的电气性能特点进行分析，得出了开关损耗小，变换器效率高、输出功率大的最佳组合工作模式为励磁电感DCM/正激电感CCM/附加电感DCM。探讨了变换器工作于该模式时，附加储能元件参数对变换器电气性能的影响，并指出开关管低电压开通性能随着附加储能元件取值的减小而提高，但附加电容的减小会使电压应力增加，且不利于续流二极管实现零电流关断；而附加电感的减小却有利于续流二极管实现零电流关断。同时推导了该模式下变换器输出电压、附加电容最大电压及附加电感和正激电感峰值电流的解析表达式。提出了一种确保变换器工作于最佳组合工作模式，且能实现开关管低电压开通与续流二极管零电流关断的电容、电感元件参数设计方法。再依据不同阶段能量传输过程的等效电路，推导出功率器件电压、电流应力解析表达式，进一步指导功率器件的选型。

根据所提出的参数设计方法，研制了一台48V/10A样机并进行仿真分析和实验研究，获取了不同工况下主要的电压和电流波形，样机满足预期设计指标要求，仿真和实验结果验证了理论分析的正确性及设计方法的可行性。

Aiming at the problems of single function, complex circuit structure and low conversion efficiency of the existing forward converter magnetic reset technology, a secondary-side LCD series forward converter that can realize multi-function multiplexing is proposed without increasing the circuit complexity. At the same time, it improves the electrical performance of the converter, which has important guiding significance for the promotion and application of the forward converter.

By analyzing the working principle and performance of the proposed converter, it is pointed out that the additional LCD branch can not only reset the magnetic core, but also transmit the excitation energy to the load side. The flow diode is turned off with zero current. The converter excitation inductance, additional inductance and forward inductance can all work in continuous conduction mode (CCM) and discontinuous conduction mode (CCM), according to which the converter is divided into 8 different Combined working mode, by analyzing the electrical performance characteristics of various combined working modes, it is concluded that the best combined working mode with low switching loss, high converter efficiency and high output power is excitation inductor DCM/forward inductor CCM/additional Inductance DCM. When the converter works in this mode, the influence of the parameters of the additional energy storage element on the electrical performance of the converter is discussed. A small value will increase the voltage stress, and is not conducive to the zero-current shutdown of the freewheeling diode; while the reduction of the additional inductance is beneficial to the freewheeling diode to achieve zero-current shutdown. At the same time, the analytical expressions of the output voltage of the converter, the maximum voltage of the additional capacitor and the peak current of the additional inductor and forward inductor in this mode are deduced. A parameter design method of capacitors and inductors is proposed to ensure that the converter works in the best combined working mode, and can realize the low-voltage turn-on of the switch tube and the zero-current turn-off of the freewheeling diode. Then, according to the equivalent circuit of the energy transfer process in different stages, the analytical expressions of the voltage and current stress of the power device are deduced to further guide the selection of the power device.

According to the proposed parameter design method, a 48V/10A prototype was developed and simulated and analyzed, and the main voltage and current waveforms under different working conditions were obtained. The prototype met the expected design index requirements. The simulation and experimental results verified The correctness of the theoretical analysis and the feasibility of the design method.

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