高频双有源桥变流器自适应死区时间控制方法

Adaptive Dead-time Control Scheme for High-switching-frequency Dual-active-bridge Converter

在高频双有源桥(DAB)变流器中,开关死区时间对变流器开关换流特性有很大影响。高频DAB变流器零电压开关(ZVS)窗口会随工作点变化且窗口时间较短,采用传统固定死区时间的方案会由于变流器在某些工作点上死区时间过长而错过ZVS窗口,导致变流器效率降低。提出一种自适应死区时间控制方法,检测高频DAB变流器初级开关管漏源极电压,通过数字控制器动态调节死区时间长度,避免了死区时间过长而错过ZVS窗口的情况,使开关器件工作在ZVS条件下,从而提高了变流器的效率。在一个5 kW/500 kHz的高频DAB变流器试验平台上验证了该控制方法的有效性。

In the high-switching-frequency dual active bridge（DAB） converter, dead-time has great influence on the swi- tching behavior of the primary side switch.With a fixed relatively long dead-time the primary side switches could miss the zero voltage switching（ZVS） window and work at hard-switching condition at certain operating points,thus the con- verter suffers high switching stress and lower efficiency.An adaptive dead-time control scheme is proposed to deal with this issue.This proposed control scheme can auto-tune the dead-time to make converter work under ZVS condition and increase the converter efficiency as long as there is ZVS window at the operating points.The effectiveness of the proposed scheme is verified in a 5 kW/500 kHz DAB converter prototype.