Project Title:

Design of a Flywheel Energy Storage Motor/Generator

	  94-1	10.03	5000

	  Design of a Flywheel Energy Storage Motor/Generator

Abstract:

A successful flywheel energy storage system depends on research 
efforts in the following four areas: (I) Mechanical design of the 
flywheel, (2) Flywheel charger/discharger design, (3) Magnetic 
bearings design and control, and (4) System integration. As NASA 
has addressed the flywheel mechanical design in other efforts. 
this proposal will concentrate on the other areas, in particular 
the charger/discharger design. Obtaining a flywheel 
charging/discharging converter that can achieve high power 
density, high efficiency, bidirectional power flow, and high 
power quality requirements for reducing flywheel vibration will 
require advanced power electronics and control. A recently 
developed three-phase zero-voltage transition PWM converter can 
theoretically meet this challenge. The converter must provide 
very precise waveform regulation in the frequency range from dc 
to 3 kHz. To provide the required low-distortion waveforms for 
the flywheel control, the converter must be switched at 
frequencies in excess of 100 kHz. Analog control. which is 
conventionally used at these frequencies, cannot meet the 
performance requirements. Advanced digital signal processing is 
required. The Phase I goal is to design and build a flywheel 
charging/discharging system having an efficiency in excess of 97% 
while meeting power quality requirements. Advanced power 
electronics and control will be studied for the magnetic 
bearings.

The commercial potential of a practical flywheel energy storage 
system are numerous. Not only could flywheels replace batteries 
in government and commercial space applications, but also in 
electric vehicles. This could have a tremendous beneficial 
environmental impact as well as economic impact.
The power electronics developed in this Phase I proposal could 
have application to other high performance motors. Virginia Power 
Technologies is particularly interested in using this SBIR 
funding to generate a product line for commercial use.

Key words

Virginia Power Technologies
P. O. Box 253
Blacksburg, VA   24063-0253