Solid state transformer based power converter control for electric vehicle applications

Transformers play an essential role in power transmission and distribution; however, advances in power electronics are increasingly replacing them with solid-state transformers (SSTs). SSTs overcome the limitations of conventional transformers by offering high controllability, bidirectional power flow, compact structure, and high-frequency operation. In addition, they provide advanced functionalities such as voltage–current regulation, reactive power support, energy storage management, and power quality improvement. Owing to these capabilities, SSTs are widely utilized in renewable energy integration, microgrids, distributed generation systems, and electric vehicle (EV) charging infrastructures. In this thesis, single-phase and three-phase SST-based dual active bridge (DAB) converters for EV applications are investigated. To achieve high dynamic response and stable operation, sliding mode control (SMC) and proportional–integral (PI) control strategies are implemented, and their performance is compared. Within the scope of the study, SST-based power converter topologies are analysed in detail. Considering criteria such as efficiency, control flexibility, bidirectional power transfer, high-frequency isolation, and energy-storage integration, a suitable structure for EV charging systems is identified. Accordingly, a high-efficiency DC/DC conversion structure based on DAB is developed. The mathematical model of the proposed SST-based DAB converter is derived, and the designed control algorithms are implemented. The dynamic and steady-state performance of the proposed model is evaluated under different load and input conditions. All modelling and simulation studies are carried out using the MATLAB/Simulink platform, which is widely employed for power system and power electronics analysis.