Dead-Time Compensated Dual Active Bridge with Online Hybrid Optimized Operation

This paper presents an operating point dependent dead-time compensation for the dual active bridge DC-DC converter operating in a hybrid optimized condition. This optimization sets a trade-off between input capacitor stress and the converter losses. However the presence of dead-time effect in any bridge type circuit leads to variation in different phase shifts and associated adverse effect on the active power transfer. The effect of dead time on the optimization process is analyzed at various operating conditions and a novel dead-time compensation the technique is proposed on the basis of switching instant link current direction obtained from the emulation of link current. Moreover, a complete closed-loop transfer function is derived and transient response of the output voltage with respect to a step change in the voltage reference is observed in both conditions (with and without compensation). An improved system dynamics is achieved with the compensation in terms of quick rising and settling time. Finally the effectiveness of the compensation technique is verified through the MATLAB-Simulink simulation model and 1kW experimental laboratory prototype.