SummaryUltra‐high voltage converters are usually employed to transform low voltage to high voltage in microgrids to produce renewable energy. However, it is challenging to develop control techniques due to the complicated structure of ultra‐high voltage converters and the numerous power switches and circuit components, which leads to poor dynamic characteristics of the system and a marked increase in fault rates. In order to understand the control theoretical characteristics of the ultra‐high voltage converter and provide a theoretical basis for circuit parameter analysis and control strategy design, this paper takes the boost converter cascaded system as an example to establish an accurate switching linear system model, discusses the control theoretical characteristics of the ultra‐high voltage converter in detail, and uses the decision theorem to draw the conclusion that the system is structurally controllable, reachable, and observable, simplifying the difficulty of analysis. The simulation and experimental findings show that the conclusion was drawn correctly. The research findings will give the boost converter cascaded systems modulation approach and circuit parameter design a theoretical foundation.