1490results about "Synchronous motors" patented technology

A wind turbine for generating electrical power from wind energy includes a turbine rotor mounted for rotation in wind, and having multiple blades for converting energy in the wind into rotational energy. A generator is coupled with said turbine rotor such that said turbine rotor drives said generator. The generator has a stationary air core armature that is located in a magnetic airgap between two generator rotor portions. The generator rotor portions have circumferential arrays of multiple alternating polarity permanent magnets attached to ferromagnetic back irons such that the permanent magnets drive magnetic flux back and forth between each rotor portion and through the stationary air core armature. The stationary air core armature has multiple phase windings of multiple individually insulated strand conductor wire that is wound with two separate portions including an active length portion and an end turn portion. The end turn portion is located outside the magnetic airgap and traverses predominately circumferentially, and the active length portion is located in the magnetic airgap and traverses predominately non-circumferentially and perpendicular to the direction of the magnetic airgap. The end turn portion has a thickness that is greater than the thickness of said active length portion in the direction of said magnetic airgap. AC voltage is induced in the multiple phase windings as the turbine rotor rotates.

A low inductance electrical machine that may be used as an alternator or motor with low armature inductance is disclosed. Arrangements of complementary armature windings are presented in which the fluxes induced by currents in the armature windings effectively cancel leading to low magnetic energy storage within the machine. This leads to low net flux levels, low core losses, low inductance and reduced tendency toward magnetic saturation. The inclusion of additional gaps in the magnetic circuit allows for independent adjustment of air gap geometry and armature inductance. Separately excited field arrangements are disclosed that allow rotor motion to effect brush-less alternator or brush-less motor operation. An exemplary geometry includes a stator including two annular rings and a concentric field coil together with a rotor structure separated from the stator by four air gaps.

A reluctance motor is provided that reduces leaking magnetic flux. To generate magnetic flux between adjacent magnetic poles in a rotor 2, permanent magnets 4 are disposed in approximate centers of split magnetic paths near a borderline area between two magnetic poles in an internal portion of the rotor. Further, each of slots 8 in a stator 1 is wound with a coil of a corresponding phase such that the vector phase and amplitude expressed by the products of the number of coil turns and the amount of passing current, namely, ampere-turns, become almost identical for each of the slots. By reducing leaking magnetic flux according to this arrangement, generated torque can be increased. As the rotor mechanical strength is enhanced, the rotor can be safely driven at a higher speed. A practical motor is obtained that simultaneously achieves improved motor characteristics and reduced torque ripples.

A method of assembling a power tool, a power tool, a method of assembling an electrical device, and an electrical device includes a switched reluctance motor. The electrical device is preferably a hand-held power tool, however, any type of electrical device that includes a switched reluctance motor may benefit from any number of aspects of the invention. In one independent aspect, the invention provides a construction that reduces tolerance stack-up. In another independent aspect, the invention provides a self-contained electronics package that plugs into a switched reluctance motor to provide control operation of the switched reluctance motor. In another independent aspect, the invention provides enhanced cooling that increases the efficiency of the electrical device using a switched reluctance motor. In another independent aspect, the invention provides an encapsulated magnet that allows for contaminant free motor control over the life of the SR motor. In another independent aspect, the invention provides an apparatus and a method for aligning magnets of a magnet hub with respect to the rotor poles the magnet poles represent.

A low inductance electrical machine which may be used as an alternator or motor with low armature inductance is disclosed. Arrangements of complementary armature windings are presented in which the fluxes induced by currents in the armature windings effectively cancel leading to low magnetic energy storage within the machine. This leads to low net flux levels, low core losses, low inductance and reduced tendency toward magnetic saturation. Separately excited field arrangements are disclosed that allow rotor motion to effect brushless alternator or brushless motor operation. An exemplary geometry includes a stator including two toroidal rings and a concentric field coil together with a rotor structure separated from the stator by four air gaps. An alternate embodiment allows for counter-rotation of two rotor elements for use as a flywheel energy storage system in which the external gyroscopic effects cancel.

A high power low RPM direct current electric motor is disclosed whereby the high power output is achieved in one of two ways or both. In the first case, the need for cooling is reduced simultaneously along with an increase in the utilization of the magnetic field present in the motor permanent magnets. This is achieved by wrapping the electromagnet core with windings that are capable of demagnetizing the rotor permanent magnets under stall conditions. Interlocking motor circuitry is provided which prevents the full activation of these motor windings until motor RPM values reach a safe level. This increases motor power while decreasing resistive losses in electromagnet windings. In the second case, the rotary portion consists of a large diameter relatively flat rotor containing permanent magnets and having built in vanes for moving air over the electromagnet stator windings providing forced air cooling.

A tranverse flux motor having multiple stator phase windings which are electronically commutated to produce a rotating flux to drive a permanent magnet rotor located externally of the stator. The stator is formed by two complementary facing pieces each carrying half the stator poles, the latter preferably being of claw pole configuration. The stator windings are sandwiched between the stator pieces and wound about cores which magnetically couple the stator pieces. Preferably the number of motor phases (P) is selected from the series 2, 3, . . . , N, the number of windings per phase (W) is selected from the series 1, 2, . . . , M, the number of poles per winding (PW) is selected from the series 2, 4, . . . , L, and the number of stator poles (SP) is equal to the product P*WP*PW and the number of rotor poles is SP±W.

A high strength induction machine, rotor, rotor cage end ring and bar joint, rotor end ring, and related methods are provided. An embodiment of an end ring and bar joint includes a main body adapted to substantially surround a rotor shaft when mounted thereto, a plurality of slots extending inwardly in a radial direction from outer peripheries of the main body, a thicker end ring section extending outwardly from a medial portion of the main body, being thicker than the outer peripheries of the main body, and also being adapted to substantially surround the rotor shaft, and a plurality of bosses extending axially and outwardly from outer peripheral portions in a direction opposite to the thicker end ring section and each adapted to receive an end portion of a rotor bar therein.

A segmented stator for a permanent magnet motor. The stator includes a plurality of stator segments forming an annular stator yoke and a plurality of stator teeth extending from an edge of the stator yoke. At least one coupling is between adjacent stator segments and shaped to allow movement of adjacent teeth in a so-called loose tooth design. Slot wedges are located between adjacent teeth to prevent the conductive windings from moving out of the slots through the slot openings. The slot wedges also prevent movement of adjacent teeth with respect to one another. The segmented stator can comprise an annular yoke with a plurality of discrete teeth or a plurality of assemblies including a rim section and a tooth section. The slot wedges can be keyed wedges that maintain their position through interlocking and / or can be integrated with a stator bobbin.

In a synchronous motor control device that corrects a deviation in rotational position which is related to a rotational position detector for a synchronous motor on which vector-control is performed, the synchronous motor control device includes: a current instruction generator that disables a torque instruction to set d-axis and q-axis current instructions as zero when a phase correction instruction is inputted; a current controller that outputs d-axis and q-axis voltage instructions based on the d-axis and q-axis current instructions; a phase correction quantity detector for determining the amount of offset in which the d-axis voltage instruction becomes zero when the phase correction instruction is inputted and the d-axis voltage instruction is not zero; an adder for adding a rotor positional angle and the amount of offset; and a voltage converter for determining three-phase voltage instructions based on the additional value, the d-axis and q-axis voltage instructions.

A rotor for an electrical motor may include a plurality of salient radial field rotor poles and a plurality of salient axial field rotor poles. The radial field rotor poles and the axial field rotor poles are respectively oriented on the rotor to receive or convey substantially perpendicular flux fields. Additionally, the radial field rotor poles may include both inner and outer peripheral rotor poles for communicating radial flux fields with separate coaxial stators.

After the rotor position has been fixed prior to the start of a motor, the driving mode can be rapidly switched to sensorless driving and the motor can be started and controlled, by conducting current conversions in such a power supply pattern that increases the starting output torque of the motor, and controlling the inverter output voltage.

A high power low RPM direct current electric motor is disclosed whereby the high power output is achieved in one of two ways or both. In the first case, the need for cooling is reduced simultaneously along with an increase in the utilization of the magnetic field present in the motor permanent magnets. This is achieved by wrapping the electromagnet core with windings that are capable of demagnetizing the rotor permanent magnets under stall conditions. Interlocking motor circuitry is provided which prevents the full activation of these motor windings until motor RPM values reach a safe level. This increases motor power while decreasing resistive losses in electromagnet windings. In the second case, the rotary portion consists of a large diameter relatively flat rotor containing permanent magnets and having built in vanes for moving air over the electromagnet stator windings providing forced air cooling.

A toroidal motor having a generally circular rotor surrounded by an annular stator is disclosed. The rotor has a plurality of poles disposed about a circumference thereof. A shaft extends axially away from the poles and is attached to the rotor. The stator is generally annular and includes an annular winding surrounding the circumference thereof. Disposed about the winding are a plurality of stator poles. The number of stator poles is generally equal to the number of rotor poles. When the winding and hence the stator is excited, a magnetic field is produced between the stator and rotor poles that creates torque upon the shaft.

An axial flux switched reluctance motor utilizes one or more rotor discs spaced along a rotor shaft, each rotor disc having a plurality of rotor poles spaced along the periphery thereof. Stator elements are distributed circumferentially about the rotor discs and form pairs of radially extending stator poles for axially straddling the rotor discs. Stator coils as switched on to energize pairs of stator poles for forming an axial and radially inward flux path for rotating the rotor poles for minimizing the flux path before switching off the stator coil. Two or more rotor discs can be rotationally indexed for providing two or more motor phases. In manufacture, rotor discs and circumferentially extending stator coils about the periphery of each rotor disc are fit to a stator housing. Each stator element is then fit radially through the stator housing and secured thereto for straddling the rotor discs.

A synchronous AC motor has a stator with stator poles arranged as a plurality of circumferentially extending stator pole groups, with each stator pole group having a pair of corresponding circumferentially extending loop-configuration stator windings disposed adjacent on either side or a single such winding disposed adjacent at one side, adjacent stator pole groups being mutually circumferentially displaced by a fixed amount corresponding to a specific electrical phase angle. A rotating magnetic field is produced by applying respective polyphase AC voltages to the windings, such that currents of mutually opposite direction flow in each pair.

A method for referencing a polyphase stepper motor by monitoring the current step response in at least one driven phase is presented. The coil current step response is compared to past step responses in order to determine when an increase in or maximum load is present. A combination of step to step variance, step response variance from mean current magnitude, and average current magnitude variance, as well as other measures can be combined to create an algorithm output. The output is compared to a pre-determined threshold and if the value is greater than the threshold, the motor is commanded to halt its position, which remains magnetically synchronous. This position is then used as a reference point to zero, or to home the motor.

The motor, which is an incorporated N-phased motor, comprises a rotor having four or more poles with N-poles and S-poles being alternately arranged in the circumferential direction, a stator having a stator core in which magnetic circuits are magnetically separated within an electrical angle of 360°, and an (N−1) number (N is a positive integer) of windings. The motor is configured so that currents of the windings can effectively work on the magnetic circuits.

A rotating electrical machine includes a two-phase rotor having two non-rotating solenoid-wound rotor coil assemblies and two interleaved pole assemblies. Each pole assembly is magnetically coupled to its respective coil assembly and rotates together with the machine shaft. Each pole assembly has four or more elongated pole pieces, two of which couple with one pole of a coil assembly and two of which couple with the other pole of that coil assembly. An exciter circuit independently controls the power variables provided to the rotor with respect to the stator to provide a variable-speed, variable-frequency (VSVF) motor system or VSVF generator system. The exciter energizes the solenoid-wound rotor coils with biphase AC electrical excitation, to produce a radial, rotating magnetic field at the pole pieces.

An arrangement of coils of different configurations for use in the stator of a slotless radial gap electromotive machine is described. The coils include coils of a first configuration and a second configuration. Each coil includes longitudinal sections and circumferential sections that form a substantially rectangular opening in the coil. The coils are nested together along the inside of a stator core so that the longitudinal sections of each coil of the first configuration are disposed in the rectangular openings of neighboring coils of the second configuration, and the longitudinal sections of the coils of the second configuration are disposed in the rectangular openings of neighboring coils of the first configuration. Other configurations of coils can be nested together inside the stator core to provide one or more additional layers of stator coils.

A switched reluctance machine includes a stator with a plurality of circumferentially-spaced stator segment assemblies that include salient stator poles and inter-polar stator slots. Each of the stator segment assemblies includes a stack of stator plates forming a stator segment core, an end cap assembly, and winding wire wound around the stator segment core and the end cap assembly. The rotor defines a plurality of rotor poles. The rotor tends to rotate relative to the stator to maximize the inductance of an energized winding. A drive circuit energizes the winding wire around the stator segment assemblies based on a rotational position of the rotor. Each stator plate includes a first radially outer rim section and a tooth section that extends radially inwardly from a first center portion of the first radially outer rim section.

An electrical machine, such as a switched reluctance motor, has a rotor and at least one electrically energizable phase winding. A control map is derived during production that includes a predetermined advance angle profile representing the energization of the phase winding with respect to the angular position of the rotor over a range of rotor speeds. This is stored in memory in a controller together with an angle correction factor to be applied to a predetermined portion of the advance angle profile. The angle correction factor compensates for the difference between a desired input power and the measured input power. The correction factor may be transmitted to the controller by means of radio frequency signals.

A brushless electrical machine, usable as a motor, generator, or alternator, has a rotor that is comprised of a rim portion and a substantially open center portion. The rim portion has a partially hollow core in which a stationary field coil is supported. Current to the field coil generates magnetic flux that circulates in a poloidal flux path in the rim, crossing a single magnetic air gap formed by the rim. Protrusions in the rim located around the circumference form poles all having the same polarity. As the rotor rotates, the flux exiting the poles passes through multiple stationary armature windings around the circumference that are located in the single air gap. An AC voltage is induced in the armature windings from rotation.

An inner-rotor-type brushless motor includes a bus bar which connects together U-phase, V-phase, and W-phase windings and connects them to output wires. The bus bar includes, as conductive members, three external terminals connected to first ends of the windings and one Y-connection terminal for connecting second ends of the windings together. The external terminals and the Y-connection terminal are disposed on the body of the bus bar such that the Y-connection terminal and the external terminals are located on one side on the circumference of the bus bar body, whereby the bus bar body has a circumferential region where the conductive members are not present. A sensor bard carrying a position detection sensor is attached the bus bar body such that the position detection sensor is located in the circumferential region where the conductive members are not present.

The invention provides an electromagnetic propulsive motor having a rotor capable of rotation around a shaft and having a plurality of radially disposed blades including blade tip portions for compressing a working fluid. The invention further provides a stator having a case frame, and a plurality of radially disposed vanes extending generally between said case frame and said shaft for directing the working fluid. A plurality of electromagnetic elements disposed within said rotor blades proximate the tip portions thereof interact electromagnetically with a plurality of electromagnetic elements disposed in said stator case frame to drive said rotor.