Fuel Cell Power Output Boosted by Innovative Air Compressor
New electric design enables continuous high boost pressure and a 70% reduction in system mass
Kenilworth, UK, 27th October 2015 – British clean technology innovation business, Aeristech, has developed a breakthrough in electric compressor technology that could double the output from a hydrogen fuel cell. It enables vehicle manufacturers to significantly increase performance or specify a considerably more compact fuel cell, improving packaging and weight.
“The power output of a fuel cell is limited by the rate at which air can be supplied to sustain the reaction between hydrogen and oxygen,” explained Aeristech C.E.O. Bryn Richards. “The hydrogen is already at high pressure, having evaporated from the liquid state, but air is usually pressurised using a blower. Our proprietary high speed motor and control technology allows us to deliver air at a much higher pressure increasing the rate at which the oxygen passes through the permeable membrane; no other motor control arrangement is able to deliver at this pressure with such a high efficiency.”
The output voltage from a fuel cell fluctuates, so a conventional electric compressor requires an intermediate voltage regulation to provide constant pressure, adding system losses. Aeristech’s unique motor control technology delivers constant torque, and therefore air pressure, independent of air volume or variation in input voltage, so can be powered directly from the fuel cell.
“Using our patented motor control technology we are the first company to deliver motors that are sufficiently cost-effective for use in electric compressor applications,” said Richards. “Compared to a competing electric compressor providing the same boost pressure, Aeristech’s compressor saves 70% mass on a full system basis including control unit, motor, and compressor. The more usual switched reluctance type high-speed motor would be unable to operate continuously at such high continuous power levels because of thermal management issues. This is why competitors tend to use heavy low-speed permanent magnet motors with step-up transmissions to run their compressors, creating a bulky system.”
Funding from Innovate UK (formerly the Technology Strategy Board) has contributed to the development of a 10kW fuel cell air compressor which is presently being tested on fuel cell stacks with a customer. The results from these tests should be available by the end of the year.
Aeristech is also able to supply a 20kW compressor, with a performance map and 400V control architecture tailored to the needs of a fuel cell powered vehicle, for testing and demonstration purposes.
Hydrogen is the most common fuel used in fuel cell-powered vehicles because of its high energy density and because the only emission it produces is water. In the fuel cell, hydrogen reacts with oxygen in a process that releases electrons as a source of electrical energy. The hydrogen is stored as a liquid while atmospheric air is used to supply the oxygen.
Aeristech is a British clean technology innovation business that is developing a range of electrically driven pressure charging technologies that will help to solve the driveability, emissions, integration and cost challenges facing the next generation of high efficiency petrol and diesel engines. Validated by highly regarded technology specialists, MAHLE Powertrain UK and Ricardo, Aeristech’s patented technologies provide both transient and continuous levels of boost, which is unlike any other product currently on the market.
The company was founded around an innovative permanent magnetic switching architecture that has enabled Aeristech to produce the most power dense electric motor of its type currently available. This core technology forms the basis of the company’s range of products, which include an electric supercharger, full electric turbocharger, fuel cell air compressor and turbine generator.
The drive to reduce emissions ahead of the EU 95g/km 2020 legislation is leading to a growth in hybridised vehicles and as a result, a rise of 48V electrical systems in vehicles. Aeristech’s proven technologies take advantage of this trend and are helping vehicle manufacturers make step-change efficiency improvements to their existing powertrains.
As a one-stop-shop for electrically driven pressure charging solutions, Aeristech designs, tests and develops every aspect of the system, from the bearings to the compressor wheel, to suit the customers’ individual application. The company is working with vehicle manufacturers and suppliers to licence innovative proprietary technologies to reduce tailpipe emissions, increase fuel efficiency and heighten driving characteristics of the next generation of ‘right-sized’ diesel and gasoline engines.
Richard Doherty at Market Engineering
+44 (0)1295 277 050