Optimization Design of Medium-Voltage Modular Converter with Terminal Transient Response Constraint

In medium-voltage power distribution systems, power electronics converters are widely used. As an alternative to designing separate power electronics converters for different applications, a universal power processing unit concept known as the power electronics building block (PEBB), was proposed in the late 1990s by the Office of Naval Research (ONR) to achieve an overall improvement in system cost, efficiency, weight, and size. These universal power processing units are used to construct power electronics systems of different functions and various voltage and power ratings; thus, applying optimization techniques to achieve a compact design for PEBBs is desired. As a commonly encountered load type, the presence of a step load in the power conditioning system can result in an undesired transient response across the internal buses. For the PEBB-based system to be optimized, it is important to guarantee that the resulted design satisfies the transient response constraints of the system; this calls for the need to embed the terminal constraint requirements into the optimization process. In this paper, a hierarchical optimization method is applied in the design process of the PEBB's main power stage, which takes into account the terminal transient response constraint. Later in the paper, it is illustrated that the design spaces for the converter-level design variables are reshaped due to the presence of design constraints.