Several problems facing society in the 21st century share a common problem: that when electronic devices heat up, they become inefficient, wasting energy. It is therefore the case that in your laptop there is significant space, weight and significant design cost associated with implementing the right cooling system to efficiently extract the heat. The laptop is however, a relatively low-power system, operating on earth at a rather pleasant 20C room temperature. Engineers are regularly facing this problem on a much larger scale, in much ambient temperatures, and in a situation where it is often difficult, expensive and often highly impractical to implement active cooling. Oil and gas engineers, attempting to harvest the fossil fuels we are still highly dependent on, face exactly this problem with the electronics that are driving the cutting tool motor. Power electronic devices delivering hundreds of Watts of power to the motor must do so in an ambient that can exceed 225C, operating miles under the ground with only slurry pumped from the surface to cool the devices. Similarly, electric cars are forced into restrictive design choices keeping the electronics as far from the engine as possible to minimise the cooling requirements. In space, near-sun planetary explorers are essentially floating refrigerators, the inner cabin cooled, at great cost to eventual mission length, down to earth-like temperatures when the temperature outside can exceed 300C around Venus or Mercury. The potential benefit for having electronics operating in these environments without cooling is huge, leading to greater efficiency, reliability and mission length, saving space, weight and importantly cost. This project looks to redesign the silicon device and to push its thermal behaviour to the absolute limit, so minimising the need for cooling, or eliminating it entirely. This is to be done by combining it with another material, silicon carbide, that will act as a heat sink placed within fractions of a micro-meter of the active device itself. These new Silicon-on-Silicon Carbide (Si/SiC) devices are expected to offer gains in device efficiency over any existing silicon device operating at elevated temperature. Alternatively, the same level of performance could be retained as with existing solutions, except at temperatures as much as 100C higher, or at much higher power (as much as 4x). The power transistor, implemented entirely with the silicon thin film, is a laterally-diffused metal-oxide-semiconductor field effect transistor (LD-MOS) or a lateral insulated gate bipolar transistor (L-IGBT), similar to those that have been developed for silicon on insulator (SOI) or silicon-on-sapphire. These devices shall be optimised for breakdown voltages rated from 50 to 600 V, making the devices ideal for applications such as downhole motor drives required by project partner Halliburton, and for solar array inverters destined for space.

This application has three distinct but interrelated research areas. The first is a method of designing microwave circuits using inter-coupled resonators. The method is extremely general, and can be used over a wide frequency range with many different technologies used in microwave circuits. The second area is using micromachined terahertz devices to exemplify the new deign techniques at a particular frequency and for a particular application. Micromachining has to be used to make accurate dimensioned waveguides with accuracies down to microns. The third area is the improvement in the micromachining process for the terahertz application.Inter-coupled resonators have been used for many years to make microwave filters. For more complex passpand responses with transmission zeros or dual bands, the inter-coupling becomes much more complex. This proposal takes this concept a stage further and proposes that whole passive systems can be made using coupled resonators or resonator superstructures. To exemplify this the authors have already demonstrated power splitters and a diplexers based on these concepts, and the proposed work is to look at antenna feed networks, Butler matrices and filter banks. The techniques can provide the design of microwave circuits at any centre frequency and will be useful in many areas. Technology is now allowing systems to be constructed at much higher frequencies; mobile communications at around 2 GHz is now commonplace, but car radar systems at 77 GHz have only just developed in the last few years, and now applications are beginning to emerge at above 100 GHz in the submillimetre wave region. Applications to 1 terahertz and above are seen as extremely important for future systems. One of the lowest loss waveguide structures is the rectangular waveguide, and this work will look at micromachined waveguide. The circuits are made by stacking layers of metalised silicon or thick resists. Two of the layers act as the top and bottom of the guide and the interleaving layer (or layers) forms the walls of the hollow rectangular tube. For 300GHz these waveguide are about 800 by 400 microns and micromachining is therefore required to make them accurately at this size. At Birmingham a reliable, accurate techniques for bonding the layers has been developed. Structures such as filters, power splitters, diplexers and triplexers will be demonstrated. The resonator superstructures will be also configured in waveguide resonators to produce submillimetre wave antenna feed networks, Butler matrices and filter banks.Finally work will be done to improve the micromachining process. This includes being able to selectively pattern the top and vertical edges of the gold coating. This will enable transitions to other transmissions structures such as coplanar waveguides as well as the ability to improve the bonding between layers. In addition work will proceed on the development of a new dielectric waveguide structure, initially looking at the embedding of quartz nano particles in the resist SU8. Providing a low loss waveguide structure will give the microwave designer another tool for circuit construction.

Power electronics and electrical machines are key components in a low-carbon future, enabling energy-efficient conversion and control solutions for a wide variety of energy and transportation applications. The strength of the UK manufacturing base and its strategic importance to the UK was highlighted in the UK government strategy document "Power Electronics: A Strategy for Success" (UK government Department for Business Innovation and Skills, October 2011). This calls for concerted action across the industrial and academic communities to ensure that the full potential of this growing global market can be realised for the UK economy. Specific recommendations relevant to the UK academic community include: 1) the development of a co-ordinated strategy for postgraduate training; 2) support for research focussing on underpinning the core technology areas whilst ensuring that the national capability in Power Electronics remains internationally leading; 3) establishment of a Virtual Centre linking world-class UK universities with each other and with industry. A core team including the universities of Bristol, Cambridge, Greenwich, Imperial College, Manchester, Newcastle, Nottingham, Sheffield, Strathclyde and Warwick, has been formed to develop this proposal for a UK Virtual Centre. Our vision is that the Centre will be the UK's internationally recognised provider of world-leading, underpinning power electronics research, combining the UK's best academic talent. It will focus on sustaining and growing power electronics in the UK by delivering transformative and exploitable new technologies, highly skilled people and by providing long-term strategic value to the UK power electronics industry. Centre activities will be divided into three main strands: research, community and pathways to impact. Our research activities will bring together the leading academic research groups from across the UK to address key research challenges, build critical mass and develop a widely recognised internationally leading research capability. We will develop a UK research strategy for power electronics which will build on foresight activities to inform our research direction. Our community support activities will build capacity through the training of researchers at doctoral and postdoctoral level. We will extend our research funding to the broader community through themed calls for pump priming, strategic support and feasibility projects. In addition we will support and coordinate responses to major initiatives from national and international funding bodies. Pathways to impact will include: 1) the establishment and development of the Centre brand and communication mechanisms, 2) the development and implementation of an exploitation plan which benefits UK industry, 3) support for government policy development and 4) the development of collaborative links with key power electronic research teams around the world. The Centre programme focuses on fundamental power electronics research at low technology readiness level (TRL) and hence supports a wide range of application areas with a medium to long-term time horizon. Key challenges to be addressed are: increased efficiency, increased power density, increased robustness, lower electromagnetic interference (EMI), higher levels of integration and lower through life cost. The work programme is split into four high-level themes of Devices, Components, Converters and Drives, each of which will address the key challenges, supported by a coordinating Hub. The themes will deliver the majority of the technical output of the Centre.

The urgent need for EV technology is clear. Consequently, this project is concerned with two key issues, namely the cost and power density of the electrical drive system, both of which are key barriers to bringing EVs to the mass market. To address these issues a great deal of underpinning basic research needs to be carried out. Here, we have analysed and divided the problem into 6 key themes and propose to build a number of demonstrators to showcase the advances made in the underlying science and engineering. We envisage that over the coming decades EVs in one or more variant forms will achieve substantial penetration into European and global automotive markets, particularly for cars and vans. The most significant barrier impeding the commercialisation EVs is currently the cost. Not until cost parity with internal combustion engine (ICE) vehicles is achieved will it become a seriously viable choice for most consumers. The high cost of EVs is often attributed to the cost of the battery, when in fact the cost of the electrical power train is much higher than that of the ICE vehicle. It is reasonable to assume that that battery technology will improve enormously in response to this massive market opportunity and as a result will cease to be the bottleneck to development as is currently perceived in some quarters. We believe that integration of the electrical systems on an EV will deliver substantial cost reductions to the fledgling EV market Our focus will therefore be on the two major areas of the electrical drive train that is generic to all types of EVs, the electrical motor and the power electronics. Our drivers will be to reduce cost and increase power density, whilst never losing sight of issues concerning manufacturability for a mass market.