Modulation and control of power converters in solid-state transformers

Due to the increased penetration of distributed generation, the existing power-distribution network needs to be transformed. so, there is a strong desire to have intelligent solid-state transformers (SST)wich is essential component in future grid called Internet of Energy (IoE) to enhance power quality, have light weight, provide fault isolation and offer additional features such as voltage regulation, VAR compensation, voltage-sag compensation, renewable energy sources and energy storage integration, bidirectional power and communication flow capability. The SST is regarded as a revolutionary technology in power-distribution systems. However,the involvement of different stages (AC-DC, DC-DC, DC-AC) of an SST makes the topology selection, hardware design, modulation techniques and controller design to become more challenging. This dissertation mainly focuses on a comprehensive study of the DC-DC and DC-AC stages of a three-stage SST configuration to address the abovementioned research challenges.