Robust Dynamic Control of Constant‐Current‐Source‐Based Dual‐Active‐Bridge DC/DC Converter Used for Off‐Board EV Charging

Due to the high-power density, inherent zero‐voltage‐switching (ZVS), and high voltage conversation ratio, the current source‐based isolated dual‐active‐bridge DAB–DC/DC converters are extensively used for charging EVs under constant‐current mode. However, the fast dynamic response of an output current is a crucial requirement for dual‐active‐bridge DC/DC converters operating as a constant‐current source. This study proposes a fast current controller (FCC) for tracking the desired output current under various input/output parameter disturbances/variations. The proposed control strategy can ensure a fast transient response with negligible overshoot/undershoot for output current during start‐up and when there are variations in the load or input voltage. Furthermore, the dynamic behavior of the current control against change in the reference current value has also been improved. A constant‐current‐based DAB–DC/DC converter is modeled and simulated in MATLAB/Simulink software and a scaled‐down 300 W lab prototype DAB–DC/DC converter is designed with the TMS320F28335 DSP controller of Texas Instruments. To verify the effectiveness of the proposed current controller, different test cases, such as a change in the load, a change in the input voltage, and a change in the desired output current, are considered. Moreover, under these test cases, the proposed current‐control strategy is compared with the conventional proportional-integral (PI) current controller, model‐based phase‐shift controller (MBPS) and load current feed‐forward controller (LCFF). Both the experimental and simulation results have validated the effectiveness of the proposed control strategy.