Non-linear active disturbance rejection control for three-phase dual-active-bridge DC/DC converter

The three-phase dual-active-bridge (DAB3) is the most promising converter topology of isolated bidirectional DC/DC converters in DC power systems. Active disturbance rejection control (ADRC) has gained research attention as voltage controller in DAB3 DC/DC converters. This paper proposes a non-linear ADRC (NL-ADRC) voltage controller for DAB3 DC/DC converters. Opposite to non-linear controllers for DAB3 converters, the developed controller achieves good performance, although its formulation is based on a simple DAB3 DC/DC converter model. This is achieved thanks to the estimation and rejection of the total disturbance, which includes converter model uncertainties. The application of the generalised ADRC concept and the employment of advanced estimation and feedback control methods in the ADRC model, for the first time in the case of DAB3 converters, bring benefits to the performance of the voltage controller. The effective disturbance rejection and nominal performance in dynamic and steady-state operation of the converter is demonstrated through results in frequency and time domains, as well as hardware-in-the-loop (HiL) tests. The effect of the control parameters is also analysed, to reveal the benefits of the proposed structure of the NL-ADRC model.