Principal Investigator: Dr. Juan Carlos Balda
The traditional fundamental-frequency power transformer is a key component in many applications where it is necessary to step up or step down the voltage from one level to another. This operation is done efficiently at the expense of needing a large size/volume. In several new applications, where size or volume is critical, a solid-state transformer may be the key to change the voltage from one level to another at the expense of lower efficiencies and greater system complexity. The main goal of this project is to develop a modular solid-state transformer (SST) for applications demanding space limitations, interconnecting solar or wind farms with the power grid, and improving power quality issues such as high fault currents. Modules are connected in series on the high-voltage (HV) side and in parallel or in series on the low-voltage (LV) side, depending on the selected application. The HV DC side of the SST module consists of a three-level full bridge topology switching under zero-current and zero-voltage switching. The LV DC side could be a two- or three-level full bridge topology depending on the applications. It is envisioned that the high-frequency link operates at about 20 kHz and a high-frequency transformer provides the required voltage ration for the selected application. Initially, the research team will consider SiC 1.2 kV MOSFETs for the HV side that will be packaged by UA. The LV side of the SST could use the same devices but their voltage rating will depend on the selected application. Applications for this prototype are not limited to distribution systems, others like electric train traction will be considered also.