Abstract: A method includes monitoring electrical output in an open control loop from a variable speed drive to a remote permanent magnet motor, the variable speed drive electrically connected to the permanent magnet motor via a power transmission line. The method includes, in response to detecting a variation in the electrical output at the variable speed drive, synchronizing a frequency of a rotor shaft of the permanent magnet motor with a constant electromagnetic field frequency of a stator of the permanent magnet motor for a predetermined period of time. After the predetermined period of time, the method includes increasing the electromagnetic field frequency of the stator to an operational frequency threshold to accelerate the frequency of the rotor shaft of the permanent magnet motor. In response to reaching the operational frequency threshold, the method includes determining an internal position of the rotor based on the variable electromagnetic field frequency.

Abstract: Electric machines with, and related methods for, improved fluid flow through the electric machines are disclosed. According to some implementations, an electric machine may include a central opening and a plurality of teeth facing inwardly toward the central opening. Slots may be defined between adjacent teeth, and a wedge may be disposed in one or more of the slots, partitioning the slots into a coils portion and an open portion. A gap may be defined between the stator core and the rotor. A fluid flow path defined from the gap and the open portions of the slots provide for improved fluid flow through the electric machine. Wedges disposed in the slots to maintain the coils into a packed state.

Abstract: A stator core for a stator of an electrical machine includes an elongate stator yoke having an interior surface that defines an axial central opening through the stator yoke. The interior surface further defines a plurality of axial channels about a perimeter of the central opening. A plurality of stator teeth are retained in the plurality of axial channels and spaced apart from one another to define to define axial channels to receive windings of the stator.

Abstract: An electric machine system includes an electric machine and a companion device. The electric machine has a stationary member and a movable member that, by interaction of magnetic fields, at least one of moves relative to the stationary member or generates electricity when moved relative to the stationary member. One of the stationary member and the movable member includes a permanent magnet. The companion device is coupled to the electric machine to communicate mechanical movement with the movable member. In certain instances, the electric machine system has adaptations for operation of the electric machine system subsea and/or in a corrosive environment.

Abstract: A stator core for a stator of an electrical machine includes an elongate stator yoke having an interior surface that defines an axial central opening through the stator yoke. The interior surface further defines a plurality of axial channels about a perimeter of the central opening. A plurality of stator teeth are retained in the plurality of axial channels and spaced apart from one another to define to define axial channels to receive windings of the stator.

Abstract: A rotor for an electric machine may include a rotor hub, a plurality of permanent magnets disposed about the rotor hub, a first sleeve circumjacent the plurality of permanent magnets, and a second sleeve. The second sleeve may be formed from a metal tape wrapped over the first sleeve. The second sleeve may be bonded to first and second end rings disposed at adjacent ends of the rotor hub. The metal tape may be applied in tension and may wrapped to form butt laps over the first sleeve. The metal tape may be corrosion resistant. Further, the second sleeve formed from the metal tape may protect the rotor from erosion and abrasion from fluid passing over the rotor.

Abstract: A stator includes an elongate core defining an inner volume to receive a rotor of an electric machine. The core includes a yoke and an array of teeth extending from the yoke toward the inner volume. The array of teeth defines slots between each pair of adjacent teeth in the array. Each slot includes a first slot region adapted to hold at least a portion of a conductive winding and a second slot region adapted to hold at least a portion of a conductive winding. The first slot region is defined by two non-parallel opposing slot side portions, and the second slot region is defined by two parallel opposing slot side portions.

Abstract: A rotor for an electrical machine includes an elongate rotor core assembly comprising a rotor core and a plurality of permanent magnets arranged in a plurality of rings around the rotor core. A composite sleeve resides around the rotor core assembly. The sleeve includes an outer layer and a segmented layer beneath the outer layer. The outer layer includes a plurality of discrete, non-overlapping circumferential bands of composite material positioned orthogonal to a longitudinal axis of the rotor core assembly.

Abstract: A sleeve about an electric machine rotor core and the plurality of permanent magnets has a fiber-reinforced composite layer about the rotor core and the plurality of permanent magnets. At least a portion of the sleeve about the rotor core and the permanent magnets has a coefficient of thermal expansion that is substantially equal to the aggregate coefficient of thermal expansion of the rotor core and the plurality of permanent magnets.

Abstract: An electric machine system includes an electric machine and a companion device. The electric machine has a stationary member and a movable member that, by interaction of magnetic fields, at least one of moves relative to the stationary member or generates electricity when moved relative to the stationary member. One of the stationary member and the movable member comprising a permanent magnet. The companion device is coupled to the electric machine to communicate mechanical movement with the movable member. In certain instances, the electric machine system has adaptations for operation of the electric machine system subsea and/or in a corrosive environment. The electric machine includes a stator that carries a conductive winding having multiple coils. A first subset of the coils are in a first configuration, and a second subset of the coils are in a second configuration.

Abstract: A rotor for an electrical machine includes a rotor hub and a plurality of permanent magnet segments affixed around a perimeter of the rotor hub. A first plurality of the permanent magnet segments have a substantially uniform arcuate span and are formed of a single unitary piece of material. A multi-piece permanent magnet segment includes at least two pieces, each having a smaller arcuate span than the first plurality of segments. The magnetization direction vector of one piece different than the magnetization direction vector of at least one other piece in each multi-piece segment.

Abstract: An electrical machine includes a stator and a rotor disposed in a housing of the electrical machine. The stator includes windings having a first set of end turns at a first end of the stator and having a second set of end turns at a second, opposing end of the stator. The stator has a substantially tubular shape and an interior lateral surface. The rotor extends through the interior of the stator. A flow inlet into a volume in the housing about the first end turns is located radially outside of the interior lateral surface of the stator. A flow outlet from the volume in the housing about the first end turns is located radially outside of the interior lateral surface. The inlet and the outlet are cooperatively arranged to communicate a flow of fluid substantially transverse across the first end of the stator.

Abstract: An electric machine system includes an electric machine and a companion device. The electric machine has a stationary member and a movable member that, by interaction of magnetic fields, at least one of moves relative to the stationary member or generates electricity when moved relative to the stationary member. One of the stationary member and the movable member includes a permanent magnet. The companion device is coupled to the electric machine to communicate mechanical movement with the movable member. In certain instances, the electric machine system has adaptations for operation of the electric machine system subsea and/or in a corrosive environment.

Abstract: An exemplary power system may include an electric machine with multiple sets of stator windings, each set of windings being coupled through a separate switch matrix to a common voltage bus, and each of which may be spatially arranged in full pitch around the stator such that stator flux harmonics are substantially reduced. The reduced stator flux harmonics may be associated with phase current harmonic content. In an example application, such power systems may operate in a generating mode to transfer mechanical energy to electrical energy on a DC voltage bus. In some illustrative embodiments, the power system may provide both high-power and high-speed (e.g., 1 MW at 8000 rpm or above) motoring and/or generating capability suitable, for example, for on-board (e.g., marine, aviation, traction) power systems.

Abstract: Circuit configurations for controlling an AC motor drive system wherein the control systems include redundancy features to compensate for possible failed system components.

Abstract: An exemplary power system may include an electric machine with multiple sets of stator windings, each set of windings being coupled through a separate switch matrix to a common voltage bus, and each of which may be spatially arranged in full pitch around the stator such that stator flux harmonics are substantially reduced. The reduced stator flux harmonics may be associated with phase current harmonic content. In an example application, such power systems may operate in a generating mode to transfer mechanical energy to electrical energy on a DC voltage bus. In some illustrative embodiments, the power system may provide both high-power and high-speed (e.g., 1 MW at 8000 rpm or above) motoring and/or generating capability suitable, for example, for on-board (e.g., marine, aviation, traction) power systems.

Abstract: An electric machine system includes an electric machine and a companion device. The electric machine has a stationary member and a movable member that, by interaction of magnetic fields, at least one of moves relative to the stationary member or generates electricity when moved relative to the stationary member. One of the stationary member and the movable member includes a permanent magnet. The companion device is coupled to the electric machine to communicate mechanical movement with the movable member. In certain instances, the electric machine system has adaptations for operation of the electric machine system subsea and/or in a corrosive environment.

Abstract: Electric machines with, and related methods for, improved fluid flow through the electric machines are disclosed. According to some implementations, an electric machine may include a central opening and a plurality of teeth facing inwardly toward the central opening. Slots may be defined between adjacent teeth, and a wedge may be disposed in one or more of the slots, partitioning the slots into a coils portion and an open portion. A gap may be defined between the stator core and the rotor. A fluid flow path defined from the gap and the open portions of the slots provide for improved fluid flow through the electric machine. Wedges disposed in the slots to maintain the coils into a packed state.

Abstract: A rotor for an electric machine may include a rotor hub, a plurality of permanent magnets disposed about the rotor hub, a first sleeve circumjacent the plurality of permanent magnets, and a second sleeve. The second sleeve may be formed from a metal tape wrapped over the first sleeve. The second sleeve may be bonded to first and second end rings disposed at adjacent ends of the rotor hub. The metal tape may be applied in tension and may wrapped to form butt laps over the first sleeve. The metal tape may be corrosion resistant. Further, the second sleeve formed from the metal tape may protect the rotor from erosion and abrasion from fluid passing over the rotor.

Abstract: A stator core for a stator of an electrical machine includes an elongate stator yoke having an interior surface that defines an axial central opening through the stator yoke. The interior surface further defines a plurality of axial channels about a perimeter of the central opening. A plurality of stator teeth are retained in the plurality of axial channels and spaced apart from one another to define to define axial channels to receive windings of the stator.