Stability analysis of digitally controlled dual active bridge converters

Abstract

The dual active bridge (DAB) converters are widely used in the energy storage equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability problem to the DAB converters. Thus, this paper, studies the stability of a digitally controlled DAB converter with an output voltage closed loop controller. Firstly, to accurately study the stability in a DAB converter, a discrete-time model established in a whole switching period is obtained. The model considers the output capacitor ESR, the digital control delay, and sample-and-hold process. By using this model, the stabilities of the DAB converter versus the proportional controller parameter and the output capacitor ESR are analyzed and the critical values are predicted accurately. Moreover, the stability boundary of the proportional controller parameter and the output capacitor ESR is also obtained. The result shows that the value of the output capacitor ESR can have a great effect on the stability region of the proportional controller parameter. Finally, the theoretical analyses are verified by the simulation and experimental results.

Small-signal Model for Dual-active-bridge Converter Considering Total Elimination of Reactive Current

“…The control structure is implemented using (12), (17) and (19), generating a non-linear system. This scheme is built considering the dynamic characteristics of the instantaneous voltages and currents within the DAB converter.…”

“…Applying SPSC modulation again in [19], the stability analysis of DAB converter is performed, where the exposed experiments show static operation points for different compensator gain values. While demonstrating the analytical stability limits, this paper does not investigate other factors such as the change of load, different steps of the reference voltage, or the converter input voltage variations, thus limiting the effectiveness of the study.…”

Wind Energy Harnessing in a Railway Infrastructure: Converter Topology and Control Proposal

“…In this paper, the SPS has been selected, since it is widely used and easy to implement [53,54,63]. The phase shift magnitude controls the active power flow between both sides of the DAB.…”

Large-signal modeling of three-phase dual active bridge converters for electromagnetic transient analysis in DC grids

“…Filter capacitors C i and C o are necessary to reduce the voltage ripple at 6f s which is induced by both bridges. Their equivalent series resistances (ESRs), R Ci and R Co , are also included because of their importance in stability analysis [29].…”