Distributing power in defence vehicles

is working on a project to help armoured fighting vehicles (AFVs) cope with the demands being placed on them by increasing numbers of electronic systems.

The company recently won a £3.5m contract from the Ministry of Defence (

) to investigate how the generation and distribution of electrical power in defence vehicles can be improved by using 610V technology. The defence contractor is working with BAE Systems and hybrid-vehicle technology specialist Provector on the programme.

Qinetiq's research team will upgrade a conventional 28V system in a demonstrator Warrior 2000 AFV to a new system that will generate and distribute electrical power at 610V for high-demand loads. At the same time, the 610V system will deliver 28V supplies to existing equipment.

Mike Parsons, technical leader of the research programme, said that this technology will be ready for demonstration at the end of this year and it will able to be installed on any existing or future range of military vehicles.

AFVs and protected patrol vehicles (PPVs) are already power-hungry machines with advanced computer systems and communication equipment, but future battlefield vehicles will be equipped with even more electronics, such as situational-awareness technology, sensors and vehicle cooling systems. All of this will place an increasing burden on existing 28V generating systems. Qinetiq's research team will design a compact engine generator and an auxiliary power unit.

According to Parsons, the generator will be based on the permanent magnet motors used in hybrid cars produced by such manufacturers as Toyota.

Permanent magnet motors use electromagnetic induction to convert surplus energy, derived from vehicle engine motion, into electricity. The core of the technology is a rotor with permanent magnets attached.

This rotor, which has stator windings around it, is connected to the vehicle engine. As the rotor and its magnets rotate, it causes a changing magnetic flux in the windings that will induce voltage and subsequently current.

'It is the most fundamental form of an electrical generator really, except it uses the benefit of the high-flux intensity of the permanent magnets to gain the efficiency,' said David Crane, business manager of the research programme.

According to Parsons, the existing AFV generators, which do not rely on magnets, are only 75 per cent efficient. 'Permanent magnet solutions are more around the 95 per cent-efficient mark,' he said.

'As well as higher efficiency, you also get higher power density,' added Parsons.

'So for the same size of generator, you can get double the power compared to the conventional way of doing it in these vehicles,' he said.

According to Crane, the high-voltage system being developed would be compatible with hybrid drive solutions, meaning that, one day, battlefield vehicles could have the hybrid drive capability of a Toyota Prius.

'The MoD has reinforced that desire within its recently announced Capability Visions research effort,' he said. 'Part of the effort will research a future protected vehicle with demonstration hybrid-electric drive. That demonstration is to be completed by 2013.'