Abstract: A closed loop current controller for an electromagnetic rail gun. It is necessary to control the muzzle velocity of a rail gun accurately for the gun to be a good artillery device. The present invention provides a closed loop control system to accurately regulate the energy transfer to a rail gun projectile and control its muzzle velocity. The rail gun control system includes a state space (state domain) control concept adapted to discrete control events that transition the system from one state to another until the final desired state (i.e., muzzle velocity) is reached. The control regulator preferably generates state transition functions that transition the projectile from state to state according to a defined current profile to provide a specified projectile muzzle velocity. The rail gun closed loop current controller also includes current reference compensation to correct for errors in previous state transitions.

Abstract: The cascaded, multi-level inverter can be found in a variety of applications and in a variety of industries. The inverter is typically used as a motor drive to provide variable voltage and variable frequency to a propulsion motor or other loads requiring variable frequency and voltage. In the present invention, the transformer is eliminated and its function included in an existing generator by adding a plurality of secondary windings to supply the isolated voltages needed by the multi-level power converter. Two specific examples of the present invention include a cascaded, multi-level inverter, or a variant referred to as the multi-source, flying source inverter, whose ac input voltage is derived from an electromagnetic generatorator.

Abstract: A control concept for large pulsed power applications that use multiple pulsed alternators to generate high-energy current pulses. Pulsed alternators produce a large reaction torque during discharge, but paired pulsed alternators are characterized by equal and opposite torque which result in a negligible reaction. However, it is necessary to synchronize the pulsed alternators prior to discharge to ensure that the load current will share equally and large transient and unequal torque reactions will not occur. The present control system utilizes closed loop feedback control to synchronize two or more pulsed alternators at the discharge speed and maintain synchronization before discharge and between multiple discharges in a burst pulse mode.

Abstract: A linear motor system including compartmentalized stator sections provides an interchangeable and serviceable alternative to other linear motors. The stator sections may be individually-energized so that power is only sent to stator sections adjacent to the thrust plate or rotor of the linear motor. A sufficiently long thrust plate is used to cover any gaps in the linear stator, and additional compensation stator sections are used to provide additional motor force to the thrust plate adjacent to these gap sections. If utilized onboard a ship, additional compensation stator sections may be incorporated into the face of deck hatches. The linear motor system can also be used to counteract gravitational effects in a large hanging door system implementation.

Abstract: The present invention provides a mechanical-electrical connector for interconnecting two separate circuits, as in two separate stator coil sections. The conductive end pieces of the stator coil sections to be interconnected are machined such that they can be inserted into the connector. The connector provides alternating conductive and dielectric layers to connect successive stator sections in an easy-to-assemble, non-permanent mechanism. A series of external jumper conductors provide interconnection between the internal conductive layers.

Abstract: A control system for a linear motor adapted to accurately supply a moving window of power to the stator coils. A plurality of individually switched stator coils run the length of a linear motor to move a rotor down the long axis of the stator. Accurate inductive-based position sensors continuously provide position data for the moving rotor. A processing unit calculates a proper time delay from a source voltage peak in order to apply power to the next stator coil in the moving direction of the rotor such that no DC offshoot/undershoot occurs. The linear motor control system optionally includes a failure prevention switching scheme in which pairs of individual stator coils on opposite sides of a double-sided stator are switched together.

Abstract: A power converter that produces variable frequency multiphase AC power from fixed or variable frequency AC power. The converter can be used to drive an AC motor for propulsion applications or other motors and loads that require variable frequency AC power. The power converter system is based on a combination of several power conversion technologies used in a power circuit topology and a regulator control system that allows for higher electrical efficiency, higher power density and lower power distortion to be achieved than is possible from any of the individual technologies. Specifically, the input and output power distortion of a frequency changer is monitored, and a group of high performance inverters are used to inject harmonic currents into a specially designed transformer to neutralize the power distortion to a specified acceptable level. By this neutralization, the power density of a solid-state electric power converter is increased (e.g., by a factor of 5-6) and power quality distortion is reduced (e.

Abstract: A permanent magnet synchronous machine with improved torque and power characteristics. A circumferential-oriented rotor assembly is provided with alternating permanent magnets and magnetic pole pieces. In order to reduce the amount of leakage flux in the rotor and increase the effective length of the permanent magnet, a trapezoidal or otherwise tapered permanent magnet structure is used. By alternating trapezoidal permanent magnet, and magnetic pole pieces, a higher intensity magnetic field is created in the air gap utilizing the same radial space in the motor without altering the weight or volume of the motor compared to conventional machines.

Abstract: A rotor assembly end turn cooling system and method in which cooling fluid is introduced at both ends of each cooling fluid passageway and at various points therebetween and spent cooling fluid is exhausted through exhaust openings disposed at various points between the ends of each cooling fluid passageway, including near the end turn corners. Multi-layered bore baffle shells and/or helical exhaust ducts having multiple channels control the flow of cooling fluid through the passageways and into axial rotor slots for expulsion into the rotor-stator gap. Each duct or channel may increase in cross-sectional area in the flow direction to maintain constant fluid flow velocity in the duct or channel. Improved end turn cooling and reduced cooling fluid temperatures maintain more consistent temperatures in the end turns and reduce the maximum hot-spot temperature to provide greater generator power densities and longer rotor coil insulation life.

Abstract: A fluid pump utilizing a canned rotor and canned stator is provided. The fluid pump has increased insulative properties over past “spool-type” pumps and has an increased ability to cool the stator, making it suitable for high temperature applications. A nuclear reactor is also provided. The reactor comprises a reactor vessel, that contains a nuclear fuel, control rods, reactor coolant and a reactor coolant pump for providing the reactor coolant to a steam generator. In a preferred embodiment, a steam generator is also provided inside the reactor vessel.

Abstract: A system and method for electromagnetically arresting an aircraft landing on an undersized runway, as on an aircraft carrier. The system preferably comprises a cross-deck pendant cable coupled to two purchase cables that are wound around low inertia purchase cable spools on opposite ends. The shafts of the purchase cable spools are mechanically coupled to one or more low inertia induction machines used to arrest the landing aircraft. As the aircraft contacts the cross-deck pendant cable and extends the purchase cables down the runway, power electronics in the system apply a torque based on closed-loop feedback to the induction machine acting as a generator, and the mechanical energy of the aircraft is converted to electrical energy at the generator and is dissipated as heat in an attached resistor. The one or more induction machines are preferably cup-type generators, and the generators may be briefly run as motors to initially reduce the tension on the purchase cables.