副边移相控制的宽范围升压DC/DC变流器

Secondary Side Phase-shift Controlled Converters for Wide Voltage Range Applications

提出一种基于副边移相控制的高效率宽范围升压型DC/DC变流器拓扑。该变流器的原边采用全桥结构,可实现大输入电流变换。副边采用改进型三电平结构,可实现倍压输出,满足后级高压并网需求。此外,所有功率器件均工作在0.5占空比,但可通过调整原副边功率器件的移相角来实现输出电压控制。由于采用副边移相控制原理,该变流器可工作在Balance、Boost和Buck 3种模式,可实现宽输入电压范围工作。而且,与传统原边移相控制变流器相比,该电路可在宽负载范围内实现零电压软开关动作,并降低了副边二极管的电压应力,提高了变流器效率。最后设计一台250-350 V输入、800 V输出2.5 kW的试验样机,实验结果验证了理论分析的正确性。

In this paper, a wide input voltage range step-up DC/DC converter with secondary side phase-shift control scheme is presented. A full-bridge structure is employed in the primary side to handle large input current and an improved three-level configuration is adopted in the secondary side to achieve a high output voltage conversion for grid-connected applications. Moreover, the phase shift angle between the primary and secondary power switches is used as the control freedom to regulate the output voltage. Furthermore, a tri-mode operation including Balance, Boost and Buck modes can be realized to achieve a wide voltage conversion. In addition, Zero-voltage-Switching （ZVS） operation can be achieved during a wide vokage range and the voltage stress across the secondary diodes is reduced compared with the conventional primary phase shift control strategy. Finally, the experimental results from a 2.5 kW 250-350 V input and 800 V output prototype are provided to verify the effectiveness of the proposed converter.