Dynamic Modeling and Experimental Validation of a Non-Isolated Bidirectional DC-DC Converter for Control-Oriented Design

This paper presents the mathematical modeling and control design of a high-power-density bidirectional DC-DC converter topology based on the three-state switching cell (3SSC). The operation stages corresponding to distinct duty cycle intervals are thoroughly analyzed, and state-space techniques are employed to derive small-signal dynamic models for both Buck and Boost modes. These models serve as the foundation for the design of digital compensators using classical frequency-domain control methods, ensuring compliance with predefined performance specifications. To verify the accuracy and applicability of the derived models, a comparative analysis is conducted between simulated and experimental closed-loop responses. The same compensators, designed using the mathematical models, are implemented both in circuit-level simulations and in a 2 kW hardware prototype operating at 200 V in Buck mode and 550 V in Boost mode, with a switching frequency of 20 kHz. The observed agreement in dynamic behavior under both reference and load disturbances validates the proposed models and confirms their suitability for control-oriented applications. This comparative validation approach represents the main contribution of the work, demonstrating that the small-signal plant models faithfully reproduce the real converter dynamics and can be reliably used in the design of digital controllers for bidirectional power conversion systems.