Isolated bidirectional DC–DC (IBDC) converters are needed in a wide range of applications including DC microgrids, electric vehicles, and energy storage devices. Among various IBDC topologies, the dual active bridge (DAB) converter is one of the most promising solutions owing to its simple and symmetric structure, the capability of zero-voltage switching (ZVS) for all switches, and the wide voltage conversion range. This chapter presents the working principle and performance characterization of the DAB converter as well as its modeling and control. Four typical modulation schemes are introduced. Based on the single-phase shift modulation, active and reactive power flows are derived. Trade-offs among ZVS operation range, component current stress, and output power rating are analyzed, providing guidance for optimizing the inductance. In terms of control, large- and small-signal circuits of the reduced-order model are developed. The small-signal model is further improved by capturing the impacts of power losses. Two typical closed loop control strategies, output voltage feedback and output voltage feedback plus output current feedforward, are introduced and designed for an example DAB converter. Both the modeling methods and control strategies are verified by piecewise linear electrical circuit simulation (PLECS). The presented performance characterizations, large- and small-signal models, and control strategies offer practical design insights for DAB converters.

Over the past centuries natural river banks have been transformed into banks with artificial revetments or sheet piles to protect them from erosion. Important river features for flora and fauna have disappeared and the ecological quality of the river reduced dramatically. Recently, the importance of the ecological function of rivers has been getting more attention. One river restoration measure is the removal of man-made bank protections to increase habitat diversity and biodiversity of riparian areas and the river basin. The river morphology may change due to the freely eroding banks in the restored section. Reference projects show that the removal of bank protection along rivers may lead to the formation of bars (e.g. Schirmer et al., 2014). Bars increase morphological diversity, providing specific habitats for flora and fauna (Kurth and Schirmer, 2014). There is a lack of knowledge about the formation of bars related to the length and location of the removal of bank protection. The length of river bank protection removal is usually limited, due to human activities along the riversides. Therefore, a guideline is needed for the design of bank protection removal to enhance habitat diversity through bar formation to make this a feasible river restoration method.

We present a novel method for caging grasps in this paper by stretching ropes on the surface of a 3D object. Both topology and shape of a model to be grasped has been
considered in our approach. Our algorithm can guarantee generating local minimal rings on every topological branches of a given model with the help of a Reeb graph. Cages and
grasps can then be computed from these rings, and physical experimental tests have been conducted to verify the robustness of our approach.