中文摘要：

面向中高压．宽电压范围输入、高可靠性中大功率变换应用，提出一种交错串并联正激变换器。变换器由两个低压桥臂和一个高压桥臂构成，3个桥臂形成两个正激单元。其中，低压桥臂开关器件电压应力为输入电压的一半，高压桥臂的电压应力等于输入电压。该变换器继承了双管正激变换器可靠性高、电压应力低、效率高的优点，同时开关管的最大占空比可以达到0．67，是传统双管正激变换器最大占空比的1．33倍，因此可以适应高压、宽输入范围场合的应用；开关管占空比小于0．5时，高压桥臂开关管可以实现软开关，占空比大于0．5时，低压桥臂开关管可以实现软开关。详细分析变换器的工作原理及特性，实验结果验证了理论分析的正确性。

英文摘要：

A novel interleaved-series/parallel forward converter （ISP-FC） was proposed for medium/high-voltage, wide input voltage range, high reliability and medium/high power applications. The ISP-FC is composed of two low-voltage switching-legs and a high-voltage switching leg. The three switching-legs construct two forward ceils. The power switches＇ voltage stress of low-voltage switching-legs is half of the input voltage while the switches＇ stress of high-voltage switching-leg is input voltages. Compared with the two-switch forward converter, in addition to the advantages of high reliability, low voltage stress and high efficiency, the maximum duty cycle of the ISP-FC can achieve 0.67, which is 1.33 times of the two-switch forward converter. The switches of the high-voltage switching-leg can achieve soft-switching when duty cycle is less than 0.5 while switches of low-voltage switching-leg can achieve soft-switching when duty cycle greater than 0.5. The operation principles and characteristics of the proposed ISP-FC was analyzed in detail and verified with experimental results.