ISSUE 011 Autumn 2021 Candela C-7 hydrofoil speedboat dossier l In conversation: Robert Hoevers l Battery recycling focus l Vehicle dynamics insight l ZeroAvia hydrogen-electric aircraft digest l Motor materials

Technical consultants Ryan Maughan founded the AVID Technology Group back in 2004, and has led its growth and development ever since. As well as being an award-winning entrepreneur, he is an engineer by background with a degree in Mechanical Engineering from UMIST and an MSc in Engineering from the University of Durham. Ryan worked in the motor racing industry in his formative years, learning about high- performance engineering and developing a unique blend of hands-on practical skills with high-level engineering expertise. After a few years of working in a high-precision machining business, AVID was born, with the mission from the outset to develop new technology that will reduce emissions and fuel consumption of vehicles through improved control. Danson Joseph has had a varied career in the electrical power industry, having worked in areas ranging from systems engineering of photovoltaic power plants to developing the battery packs for Jaguar Land Rover’s I-Pace SUV. With a PhD in electrical machines from the University of Witwatersrand in South Africa, Danson has focused on developing battery systems for automotive use. After completing the I-Pace project he formed Danecca, a battery development company with a focus on prototyping and small-scale production work, as well as testing and verifying cells and packs destined for mass production. Ryan Maughan Danson Joseph Multi-kilowatt superconductors POWER SYSTEMS Researchers in Germany have developed a coil with superconducting wires that are capable of transmitting up to 5 kW of power with minimal losses (writes Nick Flaherty). The team, at the Technical University of Munich, worked with Wurth Elektronik eiSos and superconductor coating specialist Theva Dunnschichttechnik on the design of a coil which they believe could be used for fast charging of electric aircraft. Superconducting coils are a key area of research, as they have minimal resistance and therefore high-efficiency power transfer. The main problem with them though is that as the power increases, so do the losses, which causes heating. When the temperature rises, the superconducting properties collapse. So the researchers have developed a special coil design in which the individual windings of the coil are separated from one another by spacers. This reduces the AC losses in the coil and allows power transmission in the kilowatt range. This called on the researchers to resolve a fundamental conflict. If they made the distance between the windings of the superconducting coil small, the coil would be very compact but there would be a danger of superconductivity collapse during operation. Larger separations on the other hand would result in lower power density. The team chose a coil diameter for their prototype that resulted in a higher power density than is possible in commercially available systems. The aim was to achieve the lowest possible AC resistance in the smallest possible winding space, and so compensate for the reduced geometric coupling from the spaces. The distance between the individual windings was calculated using analytical and numerical simulations. The separation is equal to approximately half the width of the superconductor. However, even a ‘high temperature’ superconducting coil needs cooling with liquid nitrogen, and the cooling vessels used cannot be made of metal. That is because the walls would heat up considerably in the magnetic field used to transfer the 5 kW of power. Windings in the coil are separated from each other by spacers to reduce the AC losses Autumn 2021 | E-Mobility Engineering 11 TheGrid