Devices Selection and Topology Comparison of Medium Voltage DC Solid State Circuit Breakers

摘要

DC grid has been treated as a viable solution to solve green-house effect and reduce the cost of fossil fuels. Compared with AC grid, DC grid shows many inherent advantages, such as high efficiency power delivery, less expensive to deploy and no need for phase and frequency synchronization. However, over current protection for DC grid require fast response. To solve this problem, solid state DC circuit breakers need to be promoted. In this thesis, thermal property was taken into consideration to find the most suitable semiconductor devices. Per unitized thermal resistance of the heat sink to the ambient was used to find the reasonable conducting current. Module MOV topology and one MOV topology were compared to see the voltage and current stress.