An Improved Two-Stage Bidirectional Converter for Electric Vehicles to Grid Applications

Quite recently, the storage capacities of electric vehicles are being deployed to dampen power fluctuations in smart grids. They are especially beneficial due to their large capacities, and the nullification of any investment costs, as well as their mobility. In this regard, a Vehicle to Grid (V2G) system is defined as discharging the vehicles’ batteries and injecting their energy back to the grid during peak hours, whilst charging them during valley hours. Nevertheless, the V2G systems suffer a minor incompetency; the low efficiency resultant from the losses in charging and discharging operations. This work aims at addressing this problem by designing a bi-directional converter that involves enhanced efficiency features. The converter contains an improved AC-DC bidirectional converter driven by sine wave pulse width modulation, feeding a dual active bridge DC-DC converter driven by a single-phase-shift modulation controller. The results indicated high power ratings, higher voltage gain, higher charging/discharging efficiencies, simple control system, and consecutively a better coordination between the grid and the electric vehicles achieved with minimal losses. The design is carried out on the SIMULINK simulation platform of MATLAB software, where the respective design was implemented and the results were discussed.