PERFORMANCE ANALYSIS OF A SOFT SWITCHED SINGLE ACTIVE BRIDGE DC-TO-DC CONVERTER UNDER TRANSIENT REGION AND LINE VARIATION USING A SLIDING MODE CONTROLLER

Abstract

With the increased popularity of efficient and robust DC/DC converters in renewable energy, electric vehicles and industry, there is a rising need for advanced control techniques that are able to account for nonlinearities and dynamical disturbances. Among isolated converter topologies, the Single Active Bridge (SAB) converter has attracted attention for its simple structure, low conduction losses and soft-switching capability. However, conventional Proportional-Integral (PI) controllers usually showed poor dynamic performance under the transients and the line variation conditions with high overshoot, long settling times and standing oscillations. This paper attempts to fill these gaps by developing and implementing a Sliding Mode Controller (SMC) for a soft-switched SAB converter. The performance of the converter was tested in steady state, transient and line variation scenarios after developing a detailed MATLAB/Simulink model. Comparative analysis showed that whereas PI controller resulted in huge overshoot (133 V) with long settling time (320 ms) under transient conditions, SMC resulted in overshoot of 28.5 V and settling time of 80 ms, while oscillations were completely eliminated under line fluctuations. These results have confirmed the dominance of SMC as a nonlinear control technique and its robustness, reliability, and suitability for high-performance SAB converter applications in today's energy and automotive systems.