Electromagnetic software designs non-electronic energy storage

June 11, 2014 // By Graham Prophet
An electromagnetic design tool is assisting with commercialisation of an innovative energy storage system – a magnetically coupled flywheel – for (in this example) construction machinery in which it can contribute 10% fuel savings

The Opera electromagnetic design tool has helped to accelerate commercial development of a new generation of innovative high speed flywheel energy storage systems. Created by the technology development company Ricardo, the energy storage systems are designed to reduce the fuel costs of hydraulically-powered construction equipment such as wheeled loaders and excavators. With the speed and flexibility of the software, Ricardo investigated and characterised over 100 different design concepts in just three months, before settling on the final design solution which employs magnetic coupling to rotate a composite flywheel at around 45,000 RPM.

The TorqStor technology stores energy in a carbon-fibre composite flywheel contained within a permanently-sealed vacuum chamber, which can be scaled in size to provide energy storage solutions for different equipment. The flywheel is linked by a magnetic coupling and gearing system, and rotates at 45,000 RPM. Integrated with a construction machine's hydraulic power system, TorqStor stores the gravitational energy that is currently unused during the downward movement of the machine’s arms or booms, and then uses it to help power subsequent upward movement. This improvement in operational efficiency enables operators to achieve fuel savings and will potentially allow machine manufacturers to use smaller capacity engines for the same load-moving performance.

When Ricardo first started development of magnetically-coupled kinetic energy storage devices a number of years ago, it looked at a number of electromagnetic simulators on the market to help shorten design-to-manufacture times. The Opera package from Cobham Technical Services emerged as the clear favourite because of its scripting flexibility for automating design investigations and ease of interfacing to other software tools, and it is now Ricardo’s electromagnetic finite element analysis (FEA) tool of choice.

The first two generations of Ricardo’s flywheel energy storage were designed for integration with the powertrains of hybrid and all-electric vehicles such as cars and buses, to provide traction power. Research indicating that even higher efficiency gains could be achieved in applications involving frequent