Electrical systems
Mechanical systems are being enhanced across the company’s main business sectors and, sometimes, replaced with more electrical systems, which are more flexible in terms of installation, operation, maintenance and management. Examples of these changes are:
- More Electric Aircraft – Electric Wing de-icing reduced the bleed air needed from the engine and the heaters are more controllable.
- Unmanned Aircraft – Electrical systems are only switched on when they are needed, hence the whole systems saves on energy.
- Electrically Powered Ship – Electrical power propulsion systems can be installed in the hull in a more flexible arrangement than a conventional engine and prop-shaft.
- Tidal Generation Limited, a company wholly owned by Rolls-Royce, has designed and built a 500kW tidal turbine. Generating electricity from the movement of the tides.
The technologies described above may seem very different, but the basic technologies for the Electrical System used in these applications are very similar, with a number of key characteristics.
Despite the different applications of the systems there are common themes across all the sectors:
- Multiple generators and motors
- Usually connected to a number of prime-movers
- Distribution Networks with high levels of power electronics
- These are used for converting AC current to DC current of visa versa
- Motor drives
- High dynamic loads
- These can be unpredictable and can have difficult characteristics
- Loads can be switched ON/OFF or run continuously, e.g. electrical motors
- Autonomous/Intelligent Networks/Distribution Network
- There is no back up so these have to be intelligent and respond quickly to faults or changes in the network
Sectors
Many new ships are moving to an electrical power system where all the engine power is converted to electricity and provides all the needs via a central power system:The main drivers for this are:
- Mechanical systems are more efficient at steady speeds but Integrated Full Electric Propulsion is more efficient when demands are more variable.
- There has been large growth in auxiliary electrical loads
- Easier to install an electrical system with distributed generation power at different locations on a ship.
Many new cruise ships and large naval ships are Full Electric and this is increasing in other areas such as Merchant.
Marine
The civil aerospace industry is also moving towards more electric architectures. Studies have been performed to try and quantify the benefits of replacing traditional mechanical systems with electrical systems.Today we have the Boeing 787, which which will be the world's most electric aircraft when it enters service.
The engine of an aircraft is the source of electrical power for all the systems on the aircraft, hence more complex electrical systems have a significant impact on our engine design.
We must therefore understand the systems better to optimise the design of our gas turbines.
We must be able to:
- Understand electrical system design
- Whole system design modelling from an aircraft point of view
- Understand of electrical generation and advanced electrical drives
- Understanding of transient and dynamic performance of systems
Future aircraft may increase these trends.
Civil Aerospace
Power requirements are driving novel design. Unmanned aircraft (UAV) are already flying and are seen to be key to the future in the Defence Aerospace sector. UAV’s can fly for many days, non-stop. Electrical systems can be managed to minimise fuel consumption, more than mechanical systems.
Defence Aerospace
Electrical systems
