A novel machine family-dual-rotor, radial-flux, toroidally wound, permanent-magnet (RFTPM) machines-is proposed in order to substantially improve machine torque density and efficiency. After the principles of operation, configurations, and features are discussed, the machine design and optimization guidelines are given. A prototype has been designed, built, and tested. The measured torque density of the prototype, which well matches the design value, is almost three times of that of the induction machine with the same power of 3 hp and speed. Meanwhile the efficiency is still kept high and the material cost is kept low by using ferrite magnets. Three novel approaches are proposed to reduce the cogging torque in the RFTPM machines, whose validity is verified by finite-element analysis results and experimental measurements.

Dual-rotor, radial-flux, toroidally-wound, permanent-magnet machines

Disclosed are transverse and/or commutated flux machines and components thereof, and methods of making and using the same. Certain exemplary stators for use in transverse and commutated flux machines may be configured with gaps therebetween, for example in order to counteract tolerance stackup. Other exemplary stators may be configured as partial stators having a limited number of magnets and/or flux concentrators thereon. Partial stators may facilitate ease of assembly and/or use with various rotors. Additionally, exemplary floating stators can allow a transverse and/or commutated flux machine to utilize an air gap independent of the diameter of a rotor. Via use of such exemplary stators, transverse and/or commutated flux machines can achieve improved performance, efficiency, and/or be sized or otherwise configured for various applications.

Transverse and/or commutated flux system rotor concepts

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.

Polyphase transverse flux motor

A permanent-magnet switched-flux (PMSF) device has an outer rotor mounted to a shaft about a central axis extending axially through the PMSF device. First and second pluralities of permanent-magnets (PMs) are respectively mounted in first and second circles, radially outwardly in first and second transverse planes extending from first and second sections of the central axis adjacent to an inner surface of the outer rotor. An inner stator is coupled to the shaft and has i) a stator core having a core axis co-axial with the central axis; and ii) first and second pluralities of stator poles mounted in first and second circles, radially outwardly from the stator core axis in the first and second transverse planes. The first and second pluralities of PMs each include PMs of alternating polarity.

Permanent-magnet switched-flux machine

An electrical machine comprising a rotor, a coil and a stator comprising a lamination stack coupled to a tooth, wherein the electrical machine is at least one of a transversal flux machine, is described. The electrical machine may be a transversal flux machine such as a transverse or commutated flux machine. A lamination ring is describes comprising a plurality of lamination stacks. A lamination stack may comprise a plurality of trenches configured to retain a plurality of teeth. The tooth may comprise a portion of the switching surface, and a portion of a lamination stack may extend to the surface of the tooth to make up a portion of the switching surface. The electrical machine may be configured with a constant air gap, wherein there is no more than 15% variability in the distance between the stator switching surface and the rotor switching surface.

Transverse and/or commutated flux systems having laminated and powdered metal portions

In order to achieve high potency for magnetic circuits together with a favourable possibility of constructing them in four-phase and two-phase form using radially positioned permanent magnets in flux concentration mode, it is proposed to introduce E-shaped stator pole elements with at least one fanned-out limb each. This gives the most favourable utilisation of the permanent magnets together with high functionality with a view to the maximum obtainable rotor diameter and favourable component manufacture. Both four-phase and two-phase machines may be constructed with the same pole elements. For exclusively two-phase windings there is a possibility of shortening the distance between the part-rotors.

Herbert Prof. Dr. Weh

Papers

Machine with transverse flux