Development and testing of a bidirectional distribution electronic power transformer model

• Development of a time-domain model for a high-frequency solid state transformer.
• Control strategy for bidirectional power flow control.
• A voltage oriented control (VOC) scheme is used for the high-voltage side stage used to ensure constant dc bus voltage, unity power factor condition at the input terminal in an average sense, and no ripple in the input active power.
• Several test cases are presented to illustrate the features of the proposed device.

Transformer size can be significantly reduced by increasing the operating frequency, which may be achieved by means of power electronics converters installed as interfaces to the power frequency systems at both transformer sides. In this work, a model for a bidirectional high-frequency power electronic transformer is presented. Several case studies have been carried out in order to evaluate the behavior of the transformer under different operating conditions and test the impact on the power quality. The results show that the electronic power transformer, also known as solid-state transformer, not only matches the functions of a conventional power transformer, but also provides additional capabilities to mitigate dynamic power quality problems.