|The AuraGen. Click to enlarge.|
Azure Dynamics Corporation incorporated Aura Systems’s AuraGen motor/generator into its Balance Hybrid Electric vehicle delivered to the United States Postal Service fleet (USPS). The Balance Hybrid Electric vehicle is a two-ton step van, and will participate in the USPS fleet in Long Island, New York for a twelve-month pilot program. The vehicle utilizes Azure Dynamics’ hybrid electric drive train on the Ford E-450 chassis.
The AuraGen is a solid rotor axial flux induction machine, comprising two stators and a solid rotor sandwiched between the stators. The stators are made from a steel ribbon with copper windings. The rotor is made from a dual casting of steel and aluminum. The AuraGen is an axial gap induction machine, rather than a squirrel cage radial gap machine.
An axial symmetric design offers a number of advantages, according to Aura, including:
- shorter flux return paths;
- much smaller total rotor volume;
- shorter stator coil end turns;
- symmetry keeps magnetic density more uniform throughout magnetic loop;
- plane of symmetry with two stators reduces volume where useless leakage can exist; and
- symmetry and geometry permit use of solid steel in rotor without efficiency penalty.
|Conduction paths and current flow. Click to enlarge.|
The AuraGen power system is able to supply simultaneous DC and AC power without interruption; power from both the generator source and a battery source during times of high power demand; real-time battery temperature monitoring, with adjustment of charging rate; and seamless power with the engine off.
The AuraGen is a load-following machine. Unlike approaches that generate the rated power, the instant power generated by the AuraGen is equal to the instant demanded load from the user, up to the rated power. This approach increases efficiency since the power generation is matched to the load at all times and at all RPMs.
The AuraGen has a continuous power rating of up to 8.5 kW, and peak power of up to 10 kW; weight is 65 lbs (29 kg).
In addition to hybrid applications, Aura is using its AuraGen and advanced power management system to support alternative energy solutions such as WePower Inc.’s vertical wind turbines.
Aura Systems. Founded in 1987, Aura Systems’s early focus was the applications of electromagnetic and electro-optics for weapon systems in the air, land and sea.
By the mid 1990s Aura was organized into 4 operating divisions: (i) AuraSound, (ii) Aura Industrial and automotive, (iii) Aura display and (iv) Newcom. In 1997, Newcom was spun out as a separate public company. The AuraGen development started in 1994 with the first working proof of concept demonstration in 1996.
Starting in 1999, Aura Systems focused all of its resources on the AuraGen (all other operations were sold and or discontinued) and in early 2001 the first AC-only, 5kW commercial units became available. In late 2001, AC/DC units as well as an 8kW unit were introduced. Mounting kits were developed for most models of GM, Ford and Chrysler vehicles.
The original founders left in 2002 and from 2002 to 2005, Aura had a number of new management teams. The company filed for Chapter 11 reorganization in June 2005 and emerged under a plan of reorganization on 1 February 2006.
Since reorganization, Aura Systems introduced a 16kW power system and numerous under-the-hood engine mounts as well as PTO and hydraulic interface options. Aura Systems was awarded the power system contract for the USCG 44-foot patrol boat, and numerous other defense-related contracts directly from government agencies or subcontract to major defense companies. In addition, Aura is now pursuing commercial and industrial applications. In the second quarter of 2008 the Company introduced and started to sell an all-electric refrigeration system for midsize trucks powered by the AuraGen.