基于中心抽头变压器的双有源桥双向直流变换器

CENTER-TAPPED TRANSFORMER BASED DUAL ACTIVE BRIDGE DC-DC CONVERTER

通过在传统双有源桥的变压器副边增加一个中心抽头并连接一个电容桥臂,提出一种改进的双有源桥双向隔离变换器,其可在宽增益范围和负载情况下实现所有功率开关管的ZVS软开关。通过调节副边全桥的桥内移相角,动态补偿实现软开关所需要的反向电流,可使所有开关管实现完全的ZVS软开通。首先分析变换器的工作原理,根据3个控制量之间的关系划分为6种工作模式。推导该变换器在不同工作模式下传输功率与控制量的关系式,详细分析软开关条件,筛选出各模式下ZVS软开关条件最差的开关管,并提出一种有效的控制方案。最后通过一台1 kW的实验样机进行实验验证。

This paper proposes a center-tapped transformer based dual active bridge DC-DC converter which can achieve ZVS within the wide voltage gain range and full load region. By adjusting the phase shift angle between the two switching legs on the secondary side, a controlled current can be provided dynamically to assist the realization of ZVS. The operation principle is presented and the possible operation modes are identified according to the relationship between three phase shift angles. The key characteristics regarding power transmission and worst ZVS scenario are analyzed in detail, and a control strategy is then proposed. Finally a 1 kW converter prototype is built and tested to verify the effectiveness and advantages of the proposed converter and control.