Engineering topics

Wolff, Frederick J.

Publications and source records attributed to Wolff, Frederick J..

3 records

NASA NTRS2001

Simulation of Flywheel Energy Storage System Controls

This paper presents the progress made in the controller design and operation of a flywheel energy storage system. The switching logic for the converter bridge circuit has been redefined to reduce line current harmonics, even at the highest operating speed of the permanent magnet motor-generator. An electromechanical machine model is utilized to simulate charge and discharge operation of the inertial energy in the flywheel. Controlling the magnitude of phase currents regulates the rate of charge and discharge. The resulting improvements are demonstrated by simulation.

Truong, Long V.↗

NASA NTRS2001

Flywheel Energy Storage Technology Being Developed

A flywheel energy storage system was spun to 60,000 rpm while levitated on magnetic bearings. This system is being developed as an energy-efficient replacement for chemical battery systems. Used in groups, the flywheels can have two functions providing attitude control for a spacecraft in orbit as well as providing energy storage. The first application for which the NASA Glenn Research Center is developing the flywheel is the International Space Station, where a two-flywheel system will replace one of the nickel-hydrogen battery strings in the space station's power system. The 60,000-rpm development rotor is about one-eighth the size that will be needed for the space station (0.395 versus 3.07 kWhr).

Wolff, Frederick J.↗

NASA NTRS2000

Simulation of a Flywheel Electrical System for Aerospace Applications

A Flywheel Energy Storage Demonstration Project was initiated at the NASA Glenn Research Center as a possible replacement for the battery energy storage system on the International Space Station (ISS). While the hardware fabrication work was being performed at a university and contractor's facility, the related simulation activity was begun at Glenn. At the top level, Glenn researchers simulated the operation of the ISS primary electrical system (as described in another paper) with the Flywheel Energy Storage Unit (FESU) replacing one Battery Charge and Discharge Unit (BCDU). The FESU consists of a Permanent Magnet Synchronous Motor/Generator (PMSM), which is connected to the flywheel; the power electronics that connects the PMSM to the ISS direct-current bus; and the associated controller. The PMSM model is still under development, but this paper describes the rest of the FESU model-the simulation of the converter and the associated control system that regulates energy transfer to and from the flywheel.

Truong, Long V.↗