|The P-50 Integrated Starter Alternator (ISA) motor.|
Raser Technologies, an R&D company developing and licensing advanced electric motors based on its proprietary Symetron technology (earlier post), announced performance results for its Symetron AC Induction Motor-based P-50 Hybrid Propulsion Integrated Starter Alternator (ISA) Drive System at the 2006 SAE World Congress in Detroit.
At 107mm (4.2 inches) in length and weighing only 30kg, the P-50 motor demonstrates 48kW of peak power, 230Nm of peak torque, and a peak efficiency of 94%. As a generator the P-50 produces 20kW of power.
This is a significant leap forward in performance for ISAs, offering automakers a more economical and reliable path to add ISA benefits rapidly to more conventional internal combustion engine (ICE) and hybrid-electric vehicle models.
Raser’s ISA Drive Systems can be applied to a wide variety of vehicles, giving automakers a high-performance cost-effective hybrid option for current makes and models, and a low-cost one-machine solution for eliminating the separate starter motors and alternators found in today’s conventional ICE vehicles.—Brent Cook, Raser CEO
Symetron is an umbrella label for several Raser innovations in motors and controllers that increase power, torque and efficiency. The Symetron technology, which can be applied in a range of packages, AC or DC, can deliver the high torque of a permanent magnet motor without the use of permanent magnets—in essence, enabling the production of smaller, more powerful and less expensive motors.
|Raser P-50 Motor|
|Peak troque||230 Nm||177 lb-ft|
|Continuous torque||120 Nm||89 lb-ft|
|Peak motor efficiency||94%|
|Peak Power||49 kW||64 hp|
|Power generation||20 kW|
|Speed range||0–6,000 rpm|
|Torque per liter||28 Nm/liter|
|Inlet coolant temp||60º C|
|Housing dimensions L x OD||127 x 295mm||5 x 11.6 inches|
|Nominal DC Bus Voltage||300 V|
There are two major design attributes of the Symetron motors contributing to their capability: full flux density at high rpm, and a 90º torque angle.
The Raser motor differs from a brushless DC motor in one major way: the usual permanent magnet rotor is replaced with an electromagnetic wound rotor. According to Raser, even with the most advanced permanent magnet neodymium super magnet materials, the flux density within the brushless DC motor is only half the flux capacity of iron. By contrast, Raser claims that its motor delivers near saturation flux capacity, effectively doubling iron utilization.
Maximizing flux density in the motor allows doubling of torque per unit of heat generation relative to a brushless DC motor. In other words, torque may be produced with less than a fourth of the energy losses. Power density is over twice as great for a given heat dissipation with a corresponding increase in motor efficiency.
The Symetron motor always operates efficiently at the ideal 90º torque angle yielding a three-fold boost in torque density (torque per pound of motor weight) over AC induction motors operating at a torque angle of 160º to 170º degrees, according to the company.
Raser sees four major benefits to its system:
Downsizing. For a comparable power output, drive systems can be smaller in size and lighter in weight.
High torque for vehicle launch assist. This makes Symetron motors good candidates for hybrid vehicle applications.
Production cost. Standard components and simplicity of design should result in costs equal to or less than current motors and controllers for a given output.
Energy savings and range extension.
One advantage of Raser’s AC induction Symetron technology is that it can be scaled economically to the higher horsepower required by full hybrids and plug-in hybrids from economy cars and light trucks to large military combat vehicles.—Timothy Fehr, Raser CTO
In October, Raser signed a Cooperative Research and Development Agreement (CRADA) with the US Army’s National Automotive Center (TAC) and their Tank Automotive Research Development and Engineering Center (TARDEC) to explore common interests in ground vehicle applications of the components, designs, and technology associated with high performance electro-magnetic equipment, especially in hybrid electric vehicle uses.
As part of the CRADA, TARDEC and Raser are investigating the possibility of using an ISA in military vehicles, using Raser’s motor technology as an ISA in the Humvee, and using Raser’s motor and controller technology in non-ISA applications in military vehicles.