Power Density Optimisation of a Linear Electrical Drive

Linear electrical machines provide a compact and mechanically efficient way of interfacing electrical power and linear motion. A linear electrical drive consists of an electrical machine, a power converter, a motion control algorithm, a power flow controller and mechanical integration. Within electric propulsion, linear electrical drives have applications in free piston engines, aerospace actuation, mag-lev and electric steering. Outside of propulsion, they are commonly found in industrial process actuation and considered in renewable energy applications.

Although the electromagnetics are common with their rotatory counterpart, the reciprocating nature of linear drives poses unique challenges to the electrical machine and power converter, resulting in pulsating electrical power and unbalanced magnetic forces. High force density, high efficiency, low cost, robust and fault tolerance are all desirable qualities, and the most appropriate design is often a compromise between these in terms of impact on overall system cost.

In this project overall power density (kW/kg) of linear electrical drives will be investigated. By integrating models of active mass, support structures and power electronic components, a scalable linear electric drive will be developed against a typical propulsion specification.

This CDT will produce power electronics specialists with industrial experience, and will equip them with key skills that are essential to meet the future power electronics challenges. They will be highly employable due to their training being embedded in industrial challenges with the potential to become future leaders through parallel entrepreneurial and business acumen training. As such, they will drive the UK forward in electric propulsion development and manufacturing. They will become ambassadors for cross-disciplinary thinking in electric propulsion and mentors to their colleagues. With its strong industrial partnership, this CDT is ideally placed to produce high impact research papers, patents and spin-outs, with support from the University's dedicated business development teams. All of this will contribute to the 10% year upon year growth of the power electronics sector in the UK, creating more jobs and added value to the UK economy.

Alongside the clear benefits to the economy this CDT will sustain and enhance the UK as a hub of expertise in this rapidly increasing area. UK R&D is set to shift dramatically to electrical technologies due to, amongst other reasons, the target to ban petrol/ diesel propulsion by 2040. Whilst the increase in R&D is welcome this target will be unsustainable without the right people to support the development of alternative technologies. This CDT will directly answer this skills shortage enabling the UK to not only meet these targets but lead the way internationally in the propulsion revolution.

Industry and policy stakeholders will benefit through-
a) Providing challenges for the students to work through

b) Knowledge exchange with the students and the academics

c) New lines of investigation/ revenue/ process improvement

d) Two way access to skills/ equipment and training

e) A skilled, challenge focused workforce


Society will benefit through-
a) Propulsion systems that are more efficient and require therefore less energy reducing cost of travel

b) Engineers with new skillsets working more cost-effective and more productive

c) Skilled workforce who are mindful considering the environmental and ethical impact

d) Graduates that understand equality, diversity and inclusion


Environment will benefit through-
a) Emission free cars powered by clean renewable energy increasing air quality and reducing global warming

b) Highly efficient planes reducing the amount of oil and therefore oil explorations in ecological sensitive areas such as the arctic can be slowed down, allowing sufficient time for the development of new alternative environmental friendly fuels.

c) Significant noise reduction leading to quiet cities and airports