Lawrence Livermore National Security, LLC

University of California

The United States of America as Represented by the United States

Lawrence Livermore National Laboratory, LLC

Richard Freeman Post

Edward G Cook

Lisle B Hagler

Charles Stuart Vann

Bernard T Merritt

Gary R Dreifuerst

A mechanical system is provided for maintaining a desired gap between a stator electrode array and a rotor electrode array by employing repelling magnets on the inner surface of the rotor and on movable carts that support azimuthally segmented stator arrays.

Stator positioner for electrostatic generator electrodes and new electrode design

Robust electro-static (ES) device embodiments, with application to energy storage flywheels as an example, are described that provide reliable, high-efficiency operation in the presence of thermal and mechanical perturbations, as well as seismic events. Electro-static generators and motors, when augmented with magnetic bearings, passive three-dimensional stabilization techniques and dynamic touch-down bearings, enable robust performance in the face of these environmental concerns, as well as efficient operation during typical operational sequences, including spin-up and steady-state modalities.

Electrostatic generator electrode-centering and seismic-isolation system for flywheel-based energy storage modules

Novel configurations of levitating passive magnetic bearing configurations are described. Such configurations can be used for the precise control of the magnitude and sign of the bearing stiffness, thereby facilitating the overall design of the system in ways that are not possible with conventional attractive or repelling bearing elements.

Halbach-array levitating passive magnetic bearing configuration

A new rotor start-up system is provided for application to rotating systems such as stationary or vehicular electromechanical battery systems. An embodiment of the system consists of a 'locator' that includes a stationary permanent-magnet pole above which is a circular ferromagnetic (e.g., iron) strip embedded in the lower, inner edge of the flywheel rotor. The lower edge of this strip is wave-like so that the magnet can pull the rotor around to a position where the position relative to the minimum capacity between the rotor and stator electrodes is such as to launch the rotor in a chosen direction, i.e., either clock-wise or counter-clockwise. Startup from rest is then accomplished by applying a short high-voltage ac or dc pulse to the EMB capacitor.

Pulsed start-up system for electrostatic generators

Electrostatic generator electrodes mounted on the outer surface of a fiber-composite rotor. The conducting strips are mounted with a slight tilt in angle such that the electrodes will experience no tension or compression effects as the rotor spins up or slows down. The compression would come about from effects associated with the Poisson Ratio. This change can eliminate any metal fatigue or loss of bonding that might have arisen if the electrodes were to be aligned with the axis.

Method using a electrostatic generator/motor rotor electrode system suitable for installation on the outer surface of an EMB rotor

A geometric design of E-S generator motor electrodes mounted on the inner surface of a fiber-composite rotor is provided. The electrode configuration is able to sustain very high g levels. The rotor may be funned of carbon-fiber wound on top of an inner E car S-glass fiber composite core. The electrode design provides the needed area to satisfy the power requirements of the storage system and utilizes a stacked wedge-like electrode array that both solves the high-g problem and results in a doubling or tripling of the electrode area, relative to that of electrodes that conform to the inner cylindrical surface of the rotor.

Electrostatic generator/motor electrodes located on the inner surface of an electromechanical battery rotor

A novel motor drive system has been described for use in electrostatic generator/motor systems based on the time variation of capacity of a rotating condenser comprised of segmented rotor and stator elements. It takes advantage of the fact that the motor action of such a system depends only on the rms value of the drive pulses, which therefore can be formed simply by periodically interrupting a high-frequency ac wave train. This new circuitry simplifies the drive system and takes advantage of recent developments of devices used in the art of inversion of dc voltages to high-frequency (tens of kiloHz) ac.

Pulse-train drive system for electrostatic generators and motors

A radial stabilizer is provided for stabilizing levitation passive bearing elements against lateral displacements. The stabilizer provides a means to introduce anisotropy in the radial stiffness of the stabilizer. The presence of anisotropic stiffness has a strongly stabilizing effect on whirl-type rotor-dynamic instabilities. The stabilizer design also provides a means for continuously monitoring the state of health of the rotor by signaling the onset of changes of balance that would be expected to precede any major failure.

Halbach-array radial stabilizer for a passive magnetic bearing

Electrostatic generator/motor rotor electrode system suitable for installation on the outer surface of an EMB rotor

A geometric design of E-S generator/motor electrodes mounted on the inner surface of a fiber-composite rotor is provided. The electrode configuration is able to sustain very high g levels. The rotor may be formed of carbon-fiber wound on top of an inner E or S-glass fiber composite core. The electrode design provides the needed area to satisfy the power requirements of the storage system and utilizes a stacked wedge-like electrode array that both solves the high-g problem and results in a doubling or tripling of the electrode area, relative to that of electrodes that conform to the inner cylindrical surface of the rotor.

By employing a combination of magnetic forces and those from electrostatic fields, a new stabilizer is able, unlike those employing dynamic effects, to function at any speed with no need for sensors or dynamically generated electrical currents. Embodiments are provided that stabilize the radial, axial and tilt instability. In addition to its use for stabilization, the radial stabilizer described herein also functions as an eccentricity detector.

Rotation-speed-independent stabilizer for passive magnetic bearing systems

A ferromagnetic shield in contact with a magnet bar at the opposite end from the working surfaces of the bar eliminates the field canceling effects that arise from the Amperian currents at that end. The optimum polarization direction for such bars is one that is parallel to the azimuthal coordinate of the bar. The field at the working surface of the bar approaches that of a bar of infinite length because the shield, located on the side opposite to that of the working surface, completely eliminates, or at least substantially reduces, the field cancellation effect that normally would occur. The magnet bars with shields can be assembled on rotors and stators in flywheel storage systems and other rotating machinery.

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Walnut Creek, CA, United States of America

Richard Freeman Post