Wisconsin Alumni Research Foundation

Harold A Peterson

Roger W Boom

Warren C Young

Narendra Mohan

Ronald W Moses, Jr

Energy derived from an alternating current power system is stored in a superconducting magnet or inductor. The transfer of the energy is reversible so that the energy stored in the superconducting magnet can be returned to the alternating current power system. Generally, the energy is stored when surplus energy is available, due to low demand. The energy stored in the superconducting magnet may be returned to the power system when demand is high. High efficiency in the storage and return of the energy is achieved. A reversible converter is provided between the alternating current system and the superconducting magnet so that the magnet is supplied with direct current when energy is being stored. The converter may be adjusted so as to convert directcurrent into alternating current when it is desired to return the stored energy to the power system. The converter may comprise a rectifier-inverter system utilizing controlled rectifiers and a variable firing angle controller which is adjustable to control the operating mode of the rectifier-inverter system. The controller may be adjusted so that the system functions as a rectifier unit to convert the alternating current to direct current for the storage of energy in the superconducting magnet. The controller may be adjusted to a different firing angle so that the system functions as an inverter to convert direct current from the magnet into alternating current which is returned to the power system. The energy storage system can have lower losses than systems of prior types, such as pumped hydro-storage systems. The superconductive magnet system also has the ability to damp electro-mechanical oscillations in the power system.

Superconductive energy storage for power systems

A power supply capable of transferring power at high current and voltage levels to a load which may be highly inductive. The power supply includes an inverter for receiving DC power and inverting it to an AC intermediate signal. The intermediate signal is rectified by a converter to provide a DC output voltage to a load. Commutation of the controlled rectifying devices within the inverter and converter are provided by capacitors connected across the output terminals of the inverter. The DC output voltage provided to the load is controlled by the frequency of the firing signals provided to the controlled rectifying devices within the inverter. A large energy storage inductor, which may be superconductive, is connected to the inverter and may be utilized to provided the pulses of power required by the load. A converter connected to an AC power system is provided to supply external power and to recharge the current flowing in the energy storage inductor. Power may be transferred reversibly, from the energy storage inductor to a load inductor and back again.

Power supply for high power loads

An active filtration system is described which may be particularly useful for filtering undesired harmonics of the fundamental AC frequency produced by AC to DC or DC to AC conversion. The filtration system of the invention produces currents of a phase, frequency and magnitude for injection into the AC system such that the undesired harmonic currents to be filtered sum with the injected currents giving a net zero current at the undesired harmonic frequency. The system can incorporate existing passive filtration elements and provides a high-impedance parallel-filtration network to prevent the filteration system from acting as a 'sink' for the ambient harmonics generated elsewhere in the AC system. Because the frequency, phase and magnitude of the injected currents are controlled, the filter of the invention remains highly effective even when these quantities and the filter component values vary.

Active filter

An inductor device having a superconducting coil winding capable of maintaining a relatively large current flowing therethrough, and a normal conducting shield winding surrounding the superconducting coil. The superconducting coil and the shield are electrically connected in parallel with the shield functioning to maintain the current and the magnetic field in the superconducting coil substantially constant. The superconducting inductor device can be used to store energy and to return the stored energy to an energy consuming load over a relatively short period without incurring large losses in the superconducting material. This result is obtained by making the self inductance of the shield substantially equal to the mutual inductance between the shield and the superconducting coil, or by inserting a controlled compensating voltage source in series with the shield, so that pulse currents are conducted by the shield. Proper spacing of the shield windings around the superconducting coil will result in substantially no magnetic field present in the coil due to current in the shield.

Shielded superconducting inductor device

An electrical magnet having at least one turn of electrical conductor which is continuously rippled in small radius arcs around is larger circumference. Each ripple in the conductor is formed to lie in a plane normal to the net magnetic field experienced by that ripple. For the special case of a planar turn of conductor, the ripples lie in substantially the same plane as the conductor turn itself. When current is flowing in the rippled conductor, the conductor will experience a magnetically induced force directed outward normal to the conductor. To oppose this outwardly directed force, the conductor is provided support by means which engage the conductor at the inner portions of the conductor between the ripples therein. The support means may consist of members or columns extending to a solid circular wall as, for example, a wall formed in bedrock. The tensile load in the rippled conductor is much less than in an unsupported large radius circular conductor, and, in addition, the rippled conductor is capable of undergoing expansions and contractions without building up damaging strain levels in the conductor. A superconducting rippled conductor magnet may be thermally insulated from warm support structure by thermal shields and vacuum dewars which are also rippled.

Growing community of inventors

Madison, WI, United States of America

Harold A Peterson