Transient Behaviors of Multiscale Megawatt Power Electronics Systems—Part I: Characteristics and Analysis

With the rapid development of the electric power grid and high-power tractions, megawatt power electronics technology is receiving tremendous attentions across the globe. The major obstacles to its further development still exist in enhancing its capability and reliability. Technical challenges and opportunities of megawatt power electronics are summarized first. It points out that the electromagnetic transient behaviors, especially at the short-timescales, are the main challenges. The transient behaviors of power electronics systems manifest themselves in the main-power loop, gate-drive loop, and control loop. After a detailed discussion of the transient behaviors, it is concluded that focusing on the multiscale transient behaviors can lead to significant overall performance improvement. A new perspective on the power electronics theory and techniques will lead to the development of a methodology for the analysis, design, and control of megawatt power electronics converters with significant improvements.