The hybrid line commutated converter (H-LCC) topology has been verified to reduce the commutation failure probability effectively, but the reverse blocking integrated gate commutated thyristor (RB-IGCT) that meets the requirements of this topology has not yet been developed. This study focuses on the optimal design of the RB-IGCT with high blocking voltage, large on-state current, and high turn-off capability. First, an emitter isolation (EI) structure is proposed to tune the low-level injection efficiency, and the forward leakage current can be reduced by 50% without degrading the on-state current. Then, a method for optimizing anode emitter is presented. A high-doped and shallow p+ emitter is preferred to control the current gain while ensuring a low on-state voltage. As to the turn-off capability, the corrugated p-base (CB) structure is used to independently improve the maximum controllable current (MCC). In addition to the corrugation amplitude, the effect of the corrugation width is verified by experiments. Finally, 8 kV RB-IGCT samples are fabricated and tested, which reach over 3 kA average on-state current and 5.5 kA MCC. This study not only provides a practical guidance to the design of the RB-IGCT but also promotes the development of the HVDC transmission system.

Silicon as the anode materials for lithium batteries has over tenfold higher specific capacity than that of the commercial graphite. However, it suffers from poor recyclability and large volume expansion (~ 400%) during the lithiation and delithiation processes. Here, we develop an effective approach to fabricate a novel silicon/void/carbon (Si/void/C) anode used in micro lithium-ion batteries. The silicon nanoparticles (SiNPs) in the anode materials enable the high capacity, while the carbonized SU-8 provides a structural support and also facilitates the fast lithium-ions transport between the electrolyte and the silicon. The nano-void space between SiNPs and carbon scaffold provides enough space for the expansion of SiNPs during intercalation and de-intercalation of lithium-ions into the anode; moreover, it is also very helpful to reduce the damage of the carbon structure and offer high cycle life. To balance the specific capacity and the stability, the Si/void/C nanocomposite with the weight ratio of 60/0/40 shows the highest specific capacity retention of 1200 mAh/g after 80 cycles with 2200 mAh/g as the initial specific capacity. In the future, the micro lithium-ion batteries can be directly prototyped on chip by the lithography techniques. [2017-0192]