Abstract: A power system including a variable speed generator set for supplying power to an electrical power grid is provided. The generator set includes an engine and a generator. A power converter is connected to the generator set and a DC bus. The power converter is configured to convert the electrical power provided by the generator set and supply the converted power to the bus. The system includes an energy storage device and a DC to DC converter connected to the energy storage device and the DC bus. A controller is configured to control the amount of power supplied by the energy storage device to the power grid.

Abstract: A fault tolerant active magnetic bearing system comprises a magnetic bearing having a rotor mounted for rotation within a stator and for coupling to a shaft. An electric power distribution system is energized from a multi-phase switched reluctance machine supplying three independent DC power buses. Each of the power buses is coupled for supplying power to a respective pair of diametrically opposite electromagnets of the magnetic bearing so as to establish multiple magnetic control axes. Multiple power controllers are each operatively connected in circuit with a separate respective power bus. The power controllers include independent power control systems each coupled to a respective pair of diametrically opposite electromagnets for independently controlling energization of each one of the pair of diametrically opposite electromagnets.

Abstract: A rotor for use in a line start permanent magnet motor comprises a rotor core having a shaft and including teeth defining slots; a rotor cage, at least a portion of which extends through the slots; and a layer of composite permanent magnet material at least partially coating the rotor core.

Abstract: A method for estimating rotor position of a switched reluctance motor during rotor start-up or low speed operation includes applying a sequence of relatively high frequency, short duration electric probing pulses to at least two inactive excitation phase windings of a multi-phase motor. The voltage and current at each of the two inactive excitation phase windings are measured and the resultant values used to compute an estimated rotor/stator linkage/flux in each of the two excitation phase windings. The computed linkage/flux and measured phase current of the two inactive excitation windings is then used in a model to determine the rotor position. In one form, rotor position is determined by establishing a table of values representing rotor position as a function of phase current for each of a plurality of values of motor phase linkage/flux and selecting from the table a value of rotor position corresponding to the measured phase current and computed linkage/flux for the phase.

Abstract: An array of three magnetic sensors in a single package is employed with a single bias magnet for sensing shaft position, speed and direction of a motor in a high magnetic noise environment. Two of the three magnetic sensors are situated in an anti-phase relationship (i.e., 180.degree. out-of-phase) with respect to the relationship between the other of the two sensors and magnetically salient target, and the third magnetic sensor is situated between the anti-phase sensors. The result is quadrature sensing with noise immunity for accurate relative position, speed and direction measurements.

Abstract: The invention comprises a switched reluctance machine including a stator and a rotor wherein the stator includes stator teeth wound with separately excitable phase windings. The separately excitable phase windings receiving a combination of signals wherein the first of those signals is a phase winding signal and the second of those signals is a magnetic bearing signal. A method of controlling a switched reluctance machine wherein the switched reluctance machine includes separately excitable stator windings. The method comprising the steps of exciting each stator winding with a signal representative of the phase excitation for that winding and superimposing on each of said windings a signal capable of producing the magnetic force necessary to support the rotor in the absence of a mechanical bearing.

Abstract: In an active magnetic bearing system employing radial or thrust bearings, rotor shaft position is determined without requiring air gap position sensors, resulting in a high reliability system. The flux paths for each respective electromagnetic force actuator of the active magnetic bearing are isolated in order to minimize the magnetic coupling therebetween. The active magnetic bearing system is controlled for mutually exclusive excitation of each of the two actuators (e.g., stator pole pairs) per control axis. A sequence of test voltage pulses is applied to the unexcited one of each actuator pole-pair. At the peak of an applied test voltage pulse, after a predetermined time interval, the pole flux linkage is estimated using either an analog or software integrator. The integrator is reset at zero current, and hence zero flux, thereby avoiding accumulation of errors.

Abstract: A fault tolerant active magnetic bearing has at least three magnetically isolated control axes. To this end, the active magnetic bearing has a segmented stator which employs non-magnetic sections for magnetically isolating adjacent electromagnetic force actuators, and hence adjacent control axes. As a result, operating force actuators are not affected by magnetic poles experiencing a fault. Hence, in a three-phase active magnetic bearing rotor suspension control system, for example, full control of rotor shaft position can be maintained with only two functioning control axes.

Abstract: In an active magnetic bearing system employing radial or thrust bearings, rotor shaft position is determined without requiring air gap position sensors, resulting in a high reliability system. The flux paths for each respective electromagnetic force actuator of the active magnetic bearing are isolated in order to minimize the magnetic coupling therebetween. In this way, the current (or magnetomotive force, mmf) in each respective actuator is functionally related to the flux therethrough, independent of the currents (or mmf's) in adjacent actuators. Application of a digital PWM pole voltage waveform during normal bearing operation results in a ripple current waveform at the PWM switching frequency. The resulting change in stator pole current and pole voltage are measured, and the average differential inductance is determined therefrom.

Abstract: An axially magnetized linear force motor employs an exteriorly faced armature (4) having a first exterior face (14) and a second exterior face (16), wherein said first face (14) is acted upon by a first axial magnetic field established by a first annular, axially polarized, permanent magnet (22) and said second face (16) is acted upon by a second axial, magnetically opposing, magnetic field established by a second annular, axially polarized, permanent magnet (26). Actuation of a coil (32) affects the first and second fields oppositely causing an imbalance of net magnetic forces. The force imbalance causes the armature (4) to displace to a point where the net magnetic force equals a counter force established by a spring (10). Positionable ferromagnetic slugs (36, 37) alter the ratio of displacement of the armature (4) to the magnitude of a signal used to actuate the coil (32).

Abstract: A rotor position estimator for a switched reluctance motor (SRM) employs a flux-current map to determine whether the actual rotor angle is closer to, or farther from, axial alignment of stator and rotor poles than a reference angle .theta..sub.r. The flux-current map is a plot of reference flux .PSI..sub.r as a function of current for the reference angle .theta..sub.r. If a flux linkage estimate .PSI..sub.i is greater than the reference flux .PSI..sub.r, then the actual rotor angle is closer to alignment than the reference angle .theta..sub.r, and the flux-map comparator output is a logic level one. If the flux linkage estimate .PSI..sub.i is lower than the reference flux .PSI..sub.r, then the actual rotor angle is farther from alignment than the reference angle .theta..sub.r, and the flux-map comparator output is a logic level zero. When the result of the flux comparison causes the flux-current map comparator to change state, the actual rotor angle is equal to the reference angle .theta..sub.

Abstract: A method and apparatus for indirectly determining rotor position in a switched reluctance motor (SRM) are based on a flux/current model of the machine, which model includes multi-phase saturation, leakage, and mutual coupling effects. The flux/current model includes a network mesh of stator, rotor and air gap reluctance terms. The network is driven by magnetomotive force (mmf) terms corresponding to the ampereturns applied to each of the stator poles. Phase current and flux sensing for each phase are performed simultaneously. The reluctance terms of the flux/current model are determined from the phase flux and current measurements. The phase current and flux measurements also determine the rotor position angle relative to alignment for each respective motor phase and which phase (or phases) is operating in its predetermined optimal sensing region defined over a range of rotor angles.