Enhancing the Performance of Super-Twisting Sliding Mode Control Techniques for Dual Active Bridge DC-DC Converters

The Dual Active Bridge (DAB) DC-DC converter has become a fundamental topology in modern power electronics because of its ability to handle bidirectional power flow, high efficiency, galvanic isolation, and suitability for medium- to high-power applications such as renewable energy systems, electric vehicles, and smart grids. However, maintaining high performance under varying conditions remains a challenge due to nonlinear behavior, parameter variations, and external disturbances. This study addresses these issues by developing and applying advanced sliding mode control (SMC) techniques to improve the dynamic performance, robustness, and reliability of DAB converters. A simplified mathematical model is created to support control design while capturing the essential dynamics of the system. This model is then used to implement and evaluate various control strategies aimed at enhancing voltage regulation and power transfer. To overcome the limitations of traditional control methods, a sliding mode based direct power control (DPC) strategy is proposed. This method directly controls the power transfer and output voltage by defining an appropriate sliding surface, enabling fast dynamic response and robustness against disturbances. However, the classical sliding mode control often suffers from chattering, a high-frequency oscillation that can lead to switching losses and stress on components. To resolve this issue, a more advanced Super-Twisting Sliding Mode Control (ST-SMC) technique is introduced. To further improve system reliability and reduce the need for physical sensors, a current observer-based sensorless control approach is developed and integrated with the sliding mode framework. This observer estimates the inductor current using available measurements, eliminating the need for direct current sensing. This lowers system cost and complexity and enhances fault tolerance and noise immunity. The proposed observer-based SMC approach is accurately estimating system states and compensating for disturbances, the controller ensures stable operation and consistent performance even under varying load dynamics. The Overall, this work contributes to the advancement of high-performance control strategies in power electronics, offering practical solutions for efficient and reliable operation of DAB DC-DC converters in next-generation energy systems.