Prodrive’s perfect performer

Motorsport and automotive technology company Prodrive has launched an electronic control unit (ECU) designed to monitor and manage hydrogen fuel cells for vehicles.

Fuel cell systems developer Intelligent Energy built the fuel cell with Peugeot in the project, the result of a call by the Technology Strategy Board.

Intelligent Energy chose Prodrive to develop the control system as the company had a rapid prototyping controller and could take the finished product, dubbed PP150, through to production.

Pete James, Prodrive technical specialist, said: ‘The ECU has to monitor all the vital statistics of the fuel cell, including the temperature, the power going out of the unit, the voltage it is developing, and the amount of oxygen that’s flowing in, to protect the fuel cell from itself. It controls valves and actuators to regulate the flow of hydrogen and oxygen going in and the by- product, water, coming out.’

Prodrive claims the 50kW fuel cell system is a first for the UK — most are smaller, with the higher power models mostly coming from the US. Although it could be used for other applications, Prodrive’s ECU was specifically designed for the stringent requirements of the automotive industry.

Prodrive gave Intelligent Energy one of its rapid prototyping controllers on which to develop the control strategy algorithms, and the outputs to monitor and control the fuel cell. From this, Prodrive built the DP200 development unit.

‘The DP200 “has the top off” so they could change the insides of the unit as they were developing the various actuators and sensors,’ said James.

‘We were able to take that specification and create the bespoke ECU for them — the PP150.’

Making an ECU to support the new technology posed some challenges for Prodrive. ‘Some of the sensors and output drives were very different to what we’re used to on an automotive vehicle. Conversely, the standard drives used to control fuel cells are not applicable to the automotive industry, so we had to design it to get those circuits to work in both environments.’

The unit had to work within a wide temperature range. The automotive industry requires components to work from -40ºC to +85ºC but, under the bonnet, the maximum rises to +125ºC. The functionality of fuel cells made the lower range a particular challenge.

‘If your car is left out overnight in Sweden it can easily get to -40ºC and you expect to just turn the key and set off,’ said James.

‘It’s a real problem for fuel cells, as they inherently have to be wet inside, making the start-up procedure of a fuel cell difficult. So the ECU itself needs to be up and running at -40ºC so it can control everything in the correct way on start-up.’

The next Technology Strategy Board project for Prodrive, a DC-to-DC power converter for hybrid and all-electric vehicles, aims to take the technology to the next stage.

‘The converter takes the energy from whatever storage device you have, whether batteries, fuel cell or supercapacitors, and it transfers it to the level required for the electric motor,’ said James.

‘It basically balances the sources out so you can use your batteries or your fuel cell more in a better optimised way. The unit we’re designing is 50kW so it matches the fuel cell nicely and we’re trying to design something smaller, lighter and lower cost than currently available.’

James claimed that no equivalent system exists for the automotive industry yet, so it could be key to the future of hybrid and all-electric vehicles. It would make them more practical by reducing the size of the capacitors or batteries for the same level of energy storage.

‘One of the problems with fuel cells in general is they’re a bit lethargic — if you step on the accelerator, they take a couple of seconds to come online,’ said James. ‘As soon as you take your foot off, they still want to give you power and they can get damaged if you don’t use the power they’re delivering.

‘If you can match the fuel cell with some batteries or supercapacitors, you’ve got another power source to give you the transience. But this only works if you can manage the power between them correctly, and that’s where a DC-to-DC converter comes in.’

Alongside the fuel cell system now under test, James believes that together the systems could form a complete solution for future fuel cell, electric and hybrid vehicles.