一种新型单开关直流高增益变换器

摘要

A novel DC high step-up Boost converter is proposed in order to solve the disadvantage of the limited voltage gain in traditional Boost converter as well as the leakage inductance in transformer and coupling inductance.By introducing two voltage-lift-unit into Boost converter,the voltage gain ratio is improved and the voltage stresses of diode and switch are reduced,as well as the current stress of switch in its opening moment while adding a small inductor to voltage-lift-unit.The working conditions of different modes in a switching period are analyzed and the DC steady-state model of the system is established.The voltage gain ratio and the voltage stress of the power devices are given.Simulation and experimental results show that the voltage gain ratio is 14.88 when the duty ratio is 65％,and the voltage stresses of switch and diode is less than that of traditional Boost converter when in the same output voltage.The converter has the advantage of high output voltage,small input current ripple,low voltage and current stress of the switch,and the inductor currents have always been in a continuous conduction mode.%针对传统Boost电路电压增益有限及变压器、耦合电感等升压电路存在漏感的问题,提出一种无变压器、无耦合电感的新型单开关高增益变换器,将2个电压升举单元引入Boost拓扑,提高了电压增益且降低了开关管、二极管电压应力,同时在电压升举单元中加入小电感,在不影响效率的情况下,抑制开关管开通瞬间的尖峰电流.详细分析了新型变换器在一个开关周期内不同模态下的工作状况,建立了系统的直流稳态模型,给出变换器的电压增益比及功率器件的电压应力.仿真和实验结果表明,当开关管占空比为65％时,电压增益约为14.88,且开关管与二极管在同等输出电压情况下,其电压应力小于传统Boost.该变换器输出电压高,输入电流纹波小,开关管电压电流应力低,且电感电流一直处于连续模式.