Area of research
Electrical and Electronic Engineering · Control and Systems Engineering
Research interest
Research topics from publications: Study on the start-up schemes for the three-stage solid state transformer applications; A Z-Source Ac Circuit Breaker. Representative work: This paper investigates two stage-by-stage start-up schemes for a three-stage solid state transformer (SST) that includes a high frequency transformer. The DC-DC converter transformer current dynamics analysis presented in this paper shows that the stage-by-stage start-up scheme may lead to a relatively large transformer current. As a result, the DC-DC converter would suffer a relatively large input inrush current. The pre-charge start-up scheme can improve the transformer current profile during the transient. The detailed analysis of those two start-up scheme is presented and the experimental verification on laboratory prototype proved the analysis of stage-by-stage start-up scheme This paper presents an ac version of the popular dc Z-source circuit breaker. The Z-source breaker is distinctive in that it has a negative current transfer characteristic. That is, an increase in output current on a short time scale will cause a sudden decrease in input current. Therefore, the Z-source breaker can react to a fault in microseconds which is also valuable in some ac applications. After introducing the schematic and operation of an ac Z-source circuit breaker, the SCR gating method is described. This turns out to be more involved than for the dc circuit breaker because of gating requirements for additional SCRs in the circuit. Detailed simulation validates the proposed ac circu