耦合电感并-串型双管正激组合变换器研究

STUDY ON A PARALLEL-SERIES CONNECTION OF DUAL TWO-TRANSISTOR FORWARD CONVERTER MODULES WITH OUTPUT FILTER COUPLED-INDUCTOR

为了克服双管正激变换器电压增益低、不适合应用于高输出电压场合的弱点,该文提出了一种耦合电感并-串型双管正激组合变换器。该组合变换器根据耦合电感的耦合系数不同,有 3 种工作方式;其中耦合系数为 1 的工作方式,电压增益最大、为双管正激变换器的 4 倍,从而使组合变换器副边续流二极管电压应力为双管正激变换器的 1/4 倍,改善了续流二极管反向恢复问题。因而,该组合变换器适合应用于高输出电压场合,并且副边续流二极管可以采用低压快恢复二极管,提高了可靠性。

To overcome the drawbacks of low voltage gain of Two-Transistor Forward Converter(TTFC) and its low output voltage application, a novel Combined Two-Transistor Forward Converter(CTTFC) is proposed in this paper, which is connected in parallel at the input-end and in series by coupled-inductor at the output-end. While the coupling coefficient of the coupled-inductor is one, the CTTFC has the highest voltage gain, which is four times that of the TTFC. So the voltage stress of the secondary side freewheeling diodes of CTTFC is one fourth of the corresponding diode of the TTFC, which improve the reverse-recovery problem of the freewheeling diodes. As a result, the CTTFC is suitable for high output voltage applications, and the secondary side freewheeling diodes can be replaced by low voltage fast recovery ones.