Virtual Direct Power Control Scheme of Dual Active Bridge DC-DC Converters for Fast Dynamic Response

One of the essential requirements for high-performance dual active bridge ( DAB) dc-dc converters as the controlled dc voltage sources is to obtain the constant output voltage rapidly and accurately under all working conditions. In order to reach fast dynamic response, combing direct power control with feedforward control strategy, this paper proposes a virtual direct power control (VDPC) scheme with single-phase-shift control for DAB dc-dc converters to face with these following extreme conditions, such as start-up, load step-change, no-load, the input voltage fluctuation, and the desired output voltage step-change. The proposed VDPC scheme of DAB dc-dc converters can achieve no overshoot and fast transient response for the output voltage in load or input voltage disturbances and start-up stage. Dynamic response of the output voltage control has been also improved when the desired value steps up and down. Finally, four control schemes consisting of traditional voltage loop control, load current feed-forward control, model-based phase-shift control, and the proposed VDPC schemes are compared and tested in a scale-down DAB dc-dc converter experimental prototype. Experimental results verify the above excellent performance of the proposed VDPC scheme and the effectiveness of theoretical analysis.