News: Microelectronics
2 December 2020
Paragraf, Rolls-Royce, TT Electronics and CSA Catapult working together in High-T Hall project
Paragraf, which is developing graphene-based electronic sensors and devices, is helping to realise what is described as an industry first by implementing a supply chain for graphene Hall-effect sensors used in high-temperature power electronics, electric machines and drives (PEMD) within the aerospace sector.
The project High-T Hall – which started in July and is now due to run for one year – stems from the UK Research and Innovation’s (UKRI) ‘Driving the Electric Revolution’ challenge and brings together Paragraf, Rolls-Royce, TT Electronics (Aero Stanrew) and the the Compound Semiconductor Applications (CSA) Catapult. It aims to demonstrate how graphene-based Hall-effect sensors can operate reliably at high temperatures, paving the way for more efficient electric engines in aerospace and beyond.
Established by UK Government agency Innovate UK (which provides funding and support for business innovation as part of UK Research and Innovation), CSA Catapult is a not-for-profit organization (headquartered in South Wales) focused on accelerating the adoption of compound semiconductors and on bringing applications to life in three technology areas – power electronics, RF & microwave, and photonics – as well as advanced packaging. It works across the UK in a range of industry sectors from automotive to medical, and from digital communications to aerospace.
Hall-effect sensors play a major role in monitoring current levels and magnetic fields in PEMD applications, which is critical to monitoring drive power consumption and machine speed and position. The deployment of conventional silicon Hall sensors is, however, restricted to environments with temperatures below 150°C and frequencies below 100kHz, which can constrain system-level design. The High-T Hall project aims to demonstrate that graphene-based Hall-effect sensors will operate reliably up to 180°C, and potentially even at temperatures of up to 230°C, allowing them to be mounted within the machine or power module enclosure. This can enable much greater flexibility in the design of new PEMD equipment aligned to silicon carbide (SiC) power devices and higher-performance, more compact electrical machines. The ability to monitor current levels more accurately and reliably should enable better overall system control, which will in turn reduce size and weight and help design more efficient electric engine systems.
The project could lead to better efficiency in all-electric engines and help to accelerate the adoption of e-planes and, more generally, electric vehicles, says Paragraf’s co-founder Ivor Guiney. “Our graphene Hall-effect sensors have already proven to possess unique cryogenic properties, so their resistance to high temperatures will help demonstrate how uniquely versatile graphene devices are from a thermal standpoint.”
As the lead partner in High-T Hall, Paragraf will design and manufacture custom Hall-effect sensors for integration into the systems of Rolls-Royce and TT Electronics. CSA Catapult will provide its packaging expertise to develop innovative packaging solutions and advanced assembly processes for realising the prototypes. Rolls-Royce and TT Electronics will test Paragraf’s graphene Hall-effect sensors in aerospace PEMD applications, with the former pioneering the use of this technology in its upcoming gas turbine product portfolio. TT Electronics will use it to develop a range of modular current sensors for use in rugged aerospace electrical systems to reduce Hall-effect sensor temperature-related errors.
“Rolls-Royce is committed to playing a leading role in reaching net zero carbon by 2050 and this includes championing sustainable power,” says Stephen Dennison, Rolls-Royce’s head of Electronics. “This project with Paragraf and the other partners will help develop a resilient supply chain that enables companies to source made-to-measure, innovative electronic components to enhance the efficiency and performance of power electronics, machines and drives.”
“Now more than ever it’s important we make a proactive effort to accelerate innovation within the aerospace supply chain,” states Owen Rolfe, business development director at TT Electronics. “In this case, higher-temperature operation of these sensing solutions has the capability to deliver significant efficiency benefits to power electronics systems,” he adds.
“The aim of project High-T Hall is to demonstrate an integrated UK supply chain solution for advanced Hall sensing within PEMD,” says CSA Catapult’s chief technology oficer & acting CEO Martin McHugh. “This will address the issues PEMDs experience when switching frequencies across a broad range of temperature conditions,” he adds. “We are very pleased to be involved in the sensor test platform and reliability testing on this project.”
The use of a graphene-based Hall-effect sensors in high-temperature aerospace environments could not only be replicated in other industries such as automotive, it may also open new opportunities for other graphene-based electronics, beyond sensors, which can help to improve efficiency and performance even further in applications such as the engines of electric vehicles (EVs).
