Underpinning Power Electronics 2017: Heterogeneous Integration

Lead Research Organisation: University of Nottingham
Department Name: Faculty of Engineering

Abstract

Power Electronics has been identified as a high priority area for investment by EPSRC due to its pivotal role in delivering many low carbon technologies from electric vehicles to renewable energy generation, distribution and Smart Grid implementation. Further, the use of wide bandgap semiconductors offer many advantages for power conversion in terms of increased efficiency, high temperature operation, reduced weight and volume and reduced costs. The effective exploitation of wide-bandgap (WBG) semiconductors such as Silicon Carbide (SiC) or Gallium Nitride (GAN) however offer significant challenges in terms of the electrical and management. The efficient operation of WBG devices at higher switching frequencies demands increased voltage and current transition rates and as such, the size and shape of traditional power module layouts become a much larger problem. The problems associated with electro-magnetic interference also increase. The present state of the art in terms of design and construction for power converters are inherently limited in this respect, largely since these technologies are specifically developed for Silicon based semiconductor devices and new methodologies are needed. The way in which power conversion is addressed needs to be changed. Design and manufacturing methodologies which include everything from switching devices through to system level connections are needed in order to fully benefit from the advertised advantages of WBG devices.
As switching speeds increase, it is envisaged that the physical size of the switching cells needs to decrease in order to capitalise on the benefits. In order to do this, more and more of the components or functionalities which traditionally sit outside the power semiconductor packages, will need to be integrated into single objects.
'Heterogeneous Integration' can be loosely described as 'the combination of dis-similar materials and components to create multi-featured, functional blocks or 'systems' and as such, this project theme, as part of the Centre for Power Electronics, will address aspects related to the inclusion of components more traditionally seen at a system level, within new and innovative power module structures. The outcomes of this research will underpin the effective use of Wide Band-Gap (WBG) semiconductors within power electronic converters.
This research, as part of the Centre for Power Electronics, will underpin the future usage of wide bandgap power semiconductors. The technologies and research addressed within this topic will generate a cost effective, high volume manufacturing methodology for the manufacture of highly optimised commutation cells which can then be used by the system designer to create a multitude of power converter sizes and topologies without the need for bespoke engineering for each new product. This technology will not only reduce the problems associated with Electro-Magnetic Interference (EMI) or thermal management of the system but will also create a much easier to use 'system block' for the designer and as such will accelerate the uptake of WBG semiconductors together with the benefits in terms of reductions in raw material usage and increased energy savings that that will bring. The resulting methodologies and technologies will give the UK a strategic advantage with respect to the state of the art of power converter design and construction and will help keep it at the leading edge as a provider of power system solutions for automotive, aerospace, renewable energies, industrial processing and consumer white goods.

Planned Impact

The project will focus on: The development of key surface preparations and processes to enable reliable electrical and thermal interfaces between inhomogeneous materials found in power module packages. The development of laminated structural build-up techniques to realise the desired embedded 3D power module structures in order to create an integrated manufacturing methodology for multi-modular, high power density power converters. The construction of suitable demonstrator cells to demonstrate the functionality and effectiveness of the developed methodologies and processes.
Stakeholders with a potential interest in the results include: members of the power electronics community who want to realise the true benefits of wide-bandgap power electronic systems, manufacturers of high performance power systems together with those interested in high volume applications, the wider engineering community who may be interested in how optimally designed wide-bandgap power electronics could enhance the performance of their existing products (e.g. automotive or aerospace organisations).
The project partners have a strong track record in generating high impact from their work, including engagement with a wide range of industrial collaborators. Impact will be primarily managed as an activity of the Centre for Power Electronics, through the Executive Management Team and the affiliated Steering Group. The aims of the Centre for Power Electronics in this area are to: Establish the Centre brand as a natural point of contact for power electronics expertise through active dissemination; build the public image of power electronics/engineering and its importance to society. To promote the transfer of knowledge and IP gained from the research to the UK industrial community and stimulate new business activity. To contribute to the development of relevant policy through engagement with national government, national and international funding bodies and professional societies and to build collaborative links with leading academic groups and other relevant industrial organisations around the world.
This project will ensure that scientific knowledge developed is demonstrated in such a way as to emphasise the impact of this knowledge, and on design and manufacturing challenges that are directly relevant to the power electronics community. This will clearly illustrate the benefit of the work to the wider power electronics community and stimulate interest in future, related projects, where the techniques could be applied in an industrial environment to bring about direct economic benefits. This project will fully utilise the routes and mechanisms for impact available from the CPE, please see attached letter of support.
Scientific advances will also be published through standard academic routes, including in power electronics and modelling journals, and also at national (IET PEMD) and international (IEEE COMPEL, IEEE ECCE, ECPE CIPS, IEEE APEC, EPE) conferences, where a large industry presence is found.
Existing links to organisations such as Power Electronics UK (directly linked to Power Electronics Centre), the Advanced Propulsion Centre (APC - power electronics spoke held at Nottingham) will allow the knowledge developed to directly feed into academic and industry orientated activities and events, and as a route for the promotion of research outputs to a wider audience. As an example, in 2016 Nottingham collaborated with Digital Engineering Spoke (DETC) of the APC. Outputs from Centre funded power electronics packaging work were used in the development of an augmented reality app which formed the centre piece of the combined UK government stand at the Cenex Low Carbon Vehicle Event, exposing our research in power electronics to senior representatives from the automotive sector. Ongoing collaboration with the APC provides a similar opportunity at LCV events in 2017 and beyond.

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