A Reconfigurable Two-stage 11kW DC-DC Resonant Converter for EV Charging with a 150-1000V Output Voltage Range

In this paper, a reconfigurable two-stage DC/DC resonant topology with a wide output voltage range of 150-1000V is proposed for Electric Vehicle (EV) charging with high efficiency over the entire load range. The proposed topology consists of an LLC resonant converter with dual secondary sides; two interleaved triangular current mode buck converters, and three additional auxiliary switches for reconfiguration. Two possible arrangements of the proposed topology are considered and compared. The analytical model of the topology is developed, which is used for the efficiency estimation of different configurations and the design of the prototype converter. An 11kW hardware demonstrator is built and tested. The maximum measured efficiency of the converter is 97.66%, with a &gt;95% efficiency over the complete 150-1000V range at full power. The proposed two-stage converter achieves the widest output voltage range reported in literature for resonant power converters, thereby capable of charging existing and future EVs very efficiently over any charging cycle.</p

A systematic design approach for objectifying Building with Nature solutions

Hydraulic engineering infrastructure is supposed to keep functioning for many years and is likely to interfere with both the natural and the social environment at various scales. Due to its long life-cycle, hydraulic infrastructure is bound to face changing environmental conditions as well as changes in societal views on acceptable solutions. This implies that sustainability and adaptability are/should be important attributes of the design, the development and operation of hydraulic engineering infrastructure. Sustainability and adaptability are central to the Building with Nature (BwN) approach. Although nature-based design philosophies, such as BwN, have found broad support, a key issue that inhibits a wider mainstream implementation is the lack of a method to objectify BwN concepts. With objectifying, we mean turning the implicit into an explicit engineerable ‘object’, on the one hand, and specifying clear design ‘objectives’, on the other. This paper proposes the “Frame of Reference” approach as a method to systematically transform BwN concepts into functionally specified engineering designs. It aids the rationalisation of BwN concepts and facilitates the transfer of crucial information between project development phases, which benefits the uptake, acceptance and eventually the successful realisation of BwN solutions. It includes an iterative approach that is well suited for assessing status changes of naturally dynamic living building blocks of BwN solutions. The applicability of the approach is shown for a case that has been realised in the Netherlands. Although the example is Dutch, the method, as such, is generically applicable

Objectifying Building with Nature strategies: Towards scale-resolving policies

By definition, Building with Nature solutions utilise services provided by the natural system and/or provide new opportunities to that system. As a consequence, such solutions are sensitive to the status of, and interact with the surrounding system. A thorough understanding of the ambient natural system is therefore necessary to meet the required specifications and to realise the potential interactions with that system. In order to be adopted beyond the pilot scale, the potential impact of multiple BwN solutions on the natural and societal systems of a region need to be established. This requires a ‘reality check’ of the effectiveness of multiple, regional-scale applications in terms of social and environmental costs and benefits. Reality checking will help establish the upscaling potential of a certain BwN measure when addressing a larger-scale issue. Conversely, it might reveal to what extent specific smaller-scale measures are suitable in light of larger regional-scale issues. This paper presents a stepwise method to approach a reality check on BwN solutions, based on the Frame of Reference method described in a companion paper (de Vries et al., 2020), and illustrates its use by two example cases. The examples show that a successful pilot project is not always a guarantee of wider applicability and that a broader application may involve dilemmas concerning environment, policy and legislation

Utilising the full potential of dredging works: ecologically enriched extraction sites

Marine extraction sites alter the morphologyof the seabed and in doing so offer uniqueopportunities to create a new environment inthese locations. A new physical lay-out meansdeeper waters and different currents andsediment characteristics, which offerconditions to develop a new ecosystem ora sanctuary for certain fish species. Thispotential has been tested in a full-scale pilotproject in an extraction site in the North Seawithin the Building with Nature researchprogramme

Sustainable development of land reclamations and shorelines full scale experiments as a driver for public - private innovations

With 80% of the world's population living in lowland urban areas by 2050, sea levels gradually rising and societal demands on the quality of living increasing, sustainable development of coastal zones becomes increasingly urgent as well as complex. Modern strategies for the design and implementation of measures for infrastructure development, coastal protection and other functions adopt the concept of Building with Nature to handle these challenges. Recently, two full scale experiments were implemented to assess the benefits of the this approach for coastal development. The Sand Motor pilot project addresses the potential concentrated nourishments on the basis of a 21 million m3 shore nourishment at the Delfland coast in the Netherlands. This unprecedented experiment aims to protect the hinterland from flooding by letting natural processes distribute sand over shoreface, beach and dunes, thus constituting a climate-robust and environmentally friendly way of coastal protection. The second experiment addresses the concept of seabed landscaping in sand extraction sites, which aims to add ecological value to the sand borrow areas after construction. Both pilots have been monitored since their completion in 2010/2011 and will be monitored extensively in the coming years