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Study on Cu-W Clad Contact Materials with Arc-less Current Commutation in a Hybrid DC Switch

Hybrid DC switches become a research focus due to its excellent performance, such as low on-state energy loss and long lifespan. With the development of semiconductor devices, it is possible to realize an arc-less current commutation in a hybrid DC switches, which further enhances reliability. However, an optimization of contacts is also necessary for matching the high-performance semiconductor devices in an arc-less hybrid DC switch. It requires the contacts with low contact resistance which is supposed to be much lower than the on-resistance of the semiconductor device. Besides, a high boiling voltage of contacts is also required which should be high enough to commutate current from contacts to semiconductor device without arc generation. Based on these requirements, a new-type Cu-W clad contact is proposed in this paper by attaching a tungsten top layer on a copper bulk. Comparisons among the new-type contacts, copper contacts, and tungsten contacts are conducted by carrying current commutation experiments in which DC current ranges from 100 A to 400 A. The results of the experiments show the new-type contacts are the most suitable for the arc-less hybrid DC switch because of its low on-state energy losses and large current capacities of the arc-less current commutations.