一种适合宽范围输出的三电平DC/DC变换器

提出了一种宽电压范围输出的三电平DC/DC变换器,其包含两组并联的主桥臂和辅助桥臂以及级联形式连接的主变压器和辅助变压器。该变换器具有低压低功率和高压高功率两种工作模式,其中低压模式下辅助桥臂不开通以降低电路损耗,高压模式下辅助桥臂开通以提高输出电压。与传统电路相比,变压器具有更低的变比,分析了传统拓扑的损耗,并比较了新拓扑与传统拓扑在不同输出模式下的效率,得出新拓扑在低压模式下具有更高效率的结论。研制了一台2 000 W的原理样机,实验数据表明,在低压模式下新拓扑的效率仍可高达94%,较传统拓扑提升了3%,验证了理论分析的正确性。

Three-level DC/DC Converter with Wide Output Voltage Range

A three-level DC/DC converter with wide output voltage range is proposed in this paper, which consists of one group of main bridge arm and one group of auxiliary bridge arm connected in parallel, as well as one main transformer and one auxiliary transformer connected in cascade. This converter works in two modes, i.e., low-voltage low-power and high-voltage high-power. The auxiliary bridge is turned off to reduce the circuit loss in the low-voltage mode, while it is turned on to improve the output voltage in the high-voltage mode. Compared with the traditional circuit, the novel transformer has an even lower turn ratio. The loss of the traditional topology is analyzed, and the efficiencies of the novel and traditional topologies in different output modes are compared, indicating that the novel topology is more efficient in the low-voltage mode. A prototype of 2 000 W was built, and experimental data show that the efficiency of the novel topology can still reach 94% in the low-voltage mode, which was 3% higher than that of the traditional topology, thus verifying the theoretical analysis.