A Dual Active Bridge Based Battery Controller with Zero Voltage Switching for a Grid-Tied Small Wind Turbine

In this paper, a design is presented for a battery charge and discharge controller, for a grid-tied small wind turbine (SWT). For this, a dual active bridge (DAB) is used, which is an isolated bidirectional DC/DC converter which has variable power flow. Zero voltage switching (ZVS) is used for high efficiencies and a power splitting algorithm is designed to keep the SWT operating at maximum power point. Previous research has presented a DAB as a battery controller, but it has not used ZVS for increased efficiency. The previous systems could also not safely be connected to the grid. An example system was designed, which reached a theoretical maximum efficiency of 98.9% and a minimum efficiency of 90%. The working of ZVS was verified through simulations, where it was shown that ZVS cannot be used over the whole input voltage range, in these regions efficiency was decreased significantly.