Handbook of Energy Storage for Transmission or ... - W2agz.com

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• Power Electronics – an inverter and rectifier that convert the raw electrical power
output of the motor/generator into conditioned electrical power with the appropriate
voltage and frequency
• Controls and Instrumentation – electronics which monitor and control the flywheel
to ensure that the system operates within design parameters
• Housing – Containment around the flywheel system, used to protect against hazardous
failure modes. It is sometimes also used to maintain a vacuum around the rotor to
reduce atmospheric friction.
Figure 3
Cross-Section Of A Flywheel Module (Courtesy NASA Glenn Research Center)
Rotor Design and Construction
The rotor, as the energy storage mechanism, is the most important component of the
flywheel energy storage system. The design of the rotor is the most significant
contributor to the effectiveness and efficiency of the system. As described above, rotors
are designed to maximize energy density at a given rotational speed, while maintaining
structural integrity in the face of rotational and thermal stresses.
Rotor designs can be divided into two broad categories of low-speed, vertical or
horizontal shaft and high-speed, usually vertical shaft rotors. Examples of each are
illustrated in Figure 4 and Figure 5. Both types of rotors have advantages and
disadvantages, and the two find uses in different applications.
Flywheels Page 5