Abstract: A method of manufacturing permanent magnets for an axial flux permanent magnet machine. The axial flux permanent magnet machine comprises a stator with a set of coils disposed circumferentially at intervals about a machine axis, and a rotor bearing a set of permanent magnets disposed circumferentially at intervals about the machine axis. The rotor and stator are spaced apart to define a gap in which magnetic flux is generally in an axial direction. The method comprises, for each (permanent) magnet, mounting the magnet in a magnet fixture in a cutting position relative to a cutting machine configured to cut along an array of cutting lines, and moving the magnet and the array of cutting lines to simultaneously make an array of cuts across the magnet, each extending through a thickness of the magnet. The cutting machine may be a wire cutting machine.

Abstract: The invention relates to an electric axial flux machine comprising a stator, a rotor having a rotor shaft and at least a first disk-shaped rotor body that is rotationally and linearly fixedly arranged on the rotor shaft, and comprising a cooling device for cooling the axial flux machine. According to the invention, the cooling device comprises a first cooling channel module for holding a coolant, said cooling channel module being designed such that is can be placed as a separate component axially directly adjacent to the rotor body, on the side remote from the stator.

Abstract: We describe techniques to reduce DC ripple voltage in an inverter by determining a plurality of switching events for each of the three phases in each Pulse Width Modulation (PWM) period. The switching events provide a desired target output voltage for the respective PWM period. From this determination of the switching events, a comparison can be made to determine a first time period between a first and second switching event across all of the phases, and a second time period between the second and a third switching event across all of the phases. The timing of one or more switching events in only one of the phases in the respective PWM period is adjusted in response to the determined time period being greater than a threshold in order to reduce the determined first or second time period.

Abstract: We describe a method and controller for controlling an axial flux machine in which an alternating current supplied to the plurality of coils injects a compensation current to reduce a mechanical resonant component of the rotor. The compensation current is a modulated current component added to at least one of the Quadrature Current (Iq) and Direct Current (Id) components (when the alternating current is represented as a vectored DC component), when the rotor is rotating over one or more ranges of rotational speeds. The modulated current component has an electrical frequency that varies over a range of frequencies between a first frequency and a second frequency depending on the rotational speed of the rotor, the range of frequencies including a frequency that is substantially the same as a fundamental mechanical resonant frequency of the rotor, and having a phase that is out of phase with the fundamental mechanical resonant frequency of the rotor.

Abstract: A stator having a plurality of stator bars disposed circumferentially at intervals around an axis is provided. Each of the stator bars has a set of windings wound therearound for generating a magnetic field generally parallel to the axis. A plurality of radially outwardly disposed electrical interconnects for connecting two or more windings together are provided radially outwardly of the plurality of stator bars and extending circumferentially along at least a portion of the outer periphery of the stator bars. A plurality of radially inwardly disposed electrical interconnects for connecting two or more windings together are also provided radially inwardly of the stator bars and extending circumferentially along at least a portion of the inner periphery of the stator bars. The outer periphery of the stator is devoid of radially outwardly disposed interconnects along one or more portions.

Abstract: Various implementations include an axial flux machine including a rotor bearing a set of permanent magnets and a stator containing electro-magnetic coil assemblies disposed circumferentially at intervals about an axis. Each coil assembly has an axially extending stator tooth one or more coils wound around the tooth. and one or more end shoes at an end of the stator tooth. The end shoes each have at least one circumferential edge adjacent a neighbouring coil assembly. In some implementations, radially innermost and outermost portions of the at least one circumferential edge are separated by a step projecting from the at least one circumferential edge. In some implementations, at least part of the at least one circumferential edge has a thickness less than a thickness of the inner radial edge thereby reducing a leakage flux between neighbouring electro-magnetic coil assemblies.

Abstract: Various implementations include a stator assembly for an axial flux permanent magnet machine. The stator assembly may include a set of stator bars and a set of shoes for the stator bars. A shoe may be provided at one or each end of a stator bar. The stator assembly may further include a set of coils each wound around a respective stator bar. Each shoe has an inner surface adjacent to the end of one of the stator bars. The end of each stator bar has a rim, and each inner surface has a cut-away region over part of the rim to reduce a component of magnetic flux at the end of the stator bar.

Abstract: Described herein is a method of manufacturing a housing for the stator of an axial flux permanent magnet machine. The housing has a cylindrical wall including a metal outer ring lined with a polymer inner ring. The method includes positioning the metal outer ring in an injection moulding machine, and with the injection moulding machine injection moulding a polymer resin onto an inner surface of the metal outer ring to fabricate the polymer inner ring. The polymer inner ring includes a gripping surface arranged to grip a portion of the outer ring, for example moulded around a formation on an inner surface of the metal outer ring. The housing is manufactured using the metal outer ring and the polymer inner ring.

Abstract: We describe techniques to reduce DC ripple voltage in an inverter by determining a plurality of switching events for each of the three phases in each Pulse Width Modulation (PWM) period. The switching events provide a desired target output voltage for the respective PWM period. From this determination of the switching events, a comparison can be made to determine a first time period between a first and second switching event across all of the phases, and a second time period between the second and a third switching event across all of the phases. The timing of one or more switching events in only one of the phases in the respective PWM period is adjusted in response to the determined time period being greater than a threshold in order to reduce the determined first or second time period.

Abstract: An axial flux machine is provided with an integrated clutch assembly, which is housed within the bore of an annulus-shaped stator of the machine. First and second rotors, located either side of the stator are attached to the clutch basket of the clutch assembly, and rotate in unison relative to the stator. A machine housing is provided between the stator and an engagement face of the clutch basket, seated on bearings between the clutch basket and machine housing, to provide a rigid structure.

Abstract: A semiconductor arrangement and an inverter incorporating the semiconductor arrangement, in particular to an inverter for use with traction power units e.g. for on and off road vehicles and stationary power inversion, are described. In the arrangement, semiconductor devices are thermally and electrically coupled to a heatsink as a module. The heatsink is configured as a bus bar to electrically connect the one or more semiconductor devices together to transmit power between the one or more semiconductor devices. The semiconductor devices may be cooled using the structure to which they are attached, and also immersed in a cooling medium to further increase the cooling of the device.

Abstract: The present invention relates to a semiconductor cooling arrangement for cooling semiconductor devices, such as power semiconductors. The semiconductor cooling arrangement comprises one or more semiconductor assemblies located in a chamber within a housing. The housing comprises inlet and outlet ports for receiving and outputting a cooling medium. The chamber is flooded with a cooling medium to cool the assemblies. The assemblies themselves each comprise a heatsink and one or more semiconductor power devices thermally coupled to the heatsink. The heatsink comprises heat exchanging elements in the form of a plurality of holes in the heatsink extending through the heatsink from one surface to another surface such that the cooling medium flows through the holes to extract heat from the heatsink.

Abstract: We describe a method of cooling an axial flux permanent magnet machine, the machine having a stator comprising a stator housing enclosing a set of coils wound on respective stator bars and disposed circumferentially at intervals about an axis of the machine, and a rotor bearing a set of permanent magnets and mounted for rotation about said axis, and wherein said rotor and stator are spaced apart along said axis to define a gap therebetween in which magnetic flux in the machine is generally in an axial direction, the method comprising: flowing a coolant through said stator housing around said coils such that said coolant flows between said coils; and controlling said coolant flow between said coils by controlling a gap between adjacent said coils; wherein said controlling of said gap comprises: providing each of said coils with a single layer of windings over said stator bar, said layer of windings comprising a ribbon-shaped wire having a greater width across a surface of the ribbon than thickness through the

Abstract: A semiconductor arrangement and an inverter incorporating the semiconductor arrangement, in particular to an inverter for use with traction power units e.g. for on and off road vehicles and stationary power inversion, are described. In the arrangement, semiconductor devices are thermally and electrically coupled to a heatsink as a module. The heatsink is configured as a bus bar to electrically connect the one or more semiconductor devices together to transmit power between the one or more semiconductor devices. The semiconductor devices may be cooled using the structure to which they are attached, and also immersed in a cooling medium to further increase the cooling of the device.

Abstract: A double-rotor single stator axial flux machine, which is supplied having no bearings between the rotors and stator internal of the machine, is mounted to an external structure such as an interface of an engine of a vehicle or a portion of the transmission of a vehicle. The machine is mounted to the structure via the shaft of the machine (on which are seated bearings located in the structure) and the stator housing. The bearings of the structure, which are external to the machine, permit the rotors to rotate relative to the stator when the machine is installed on the structure.

Abstract: A rotor for an axial flux permanent magnet machine is described. The machine has a stator comprising a stator housing enclosing a set of coils wound on stator bars or teeth and disposed circumferentially at intervals about an axis on the machine, and a rotor bearing a set of permanent magnets and mounted for rotation about the said axis. The rotor and stator are spaced apart along said axis to define a gap therebetween in which magnet flux in the machine is generally in an axial direction. The magnets are disposed circumferentially around said rotor and define a plurality, n, of matching sets of magnets. Each set of magnets includes a plurality of magnets, wherein said n sets of magnets on said rotor have n-fold rotational symmetry. Within a said set, the magnets have different shapes and/or relative circumferential spacings of adjacent magnets within the set of magnets are irregular.

Abstract: The present invention relates to a semiconductor cooling arrangement for cooling semiconductor devices, such as power semiconductors. The semiconductor cooling arrangement comprises one or more semiconductor assemblies located in a chamber within a housing. The housing comprises inlet and outlet ports for receiving and outputting a cooling medium. The chamber is flooded with a cooling medium to cool the assemblies. The assemblies themselves each comprise a heatsink and one or more semiconductor power devices thermally coupled to the heatsink. The heatsink comprises heat exchanging elements in the form of a plurality of holes in the heatsink extending through the heatsink from one surface to another surface such that the cooling medium flows through the holes to extract heat from the heatsink.

Abstract: The present invention provides an axial flux motor (10) having: a rotor (20) having a radially extending portion (20r) and an axially extending portion (20c) having a first side (20a) and a second side (20b); a stator (22) having an inner aperture (30), a front wall (34) having a first side (34s) and a second side (34i) and being axially spaced from the first side (20a) of the rotor (20) by a gap (38), a bearing member (32) within the inner aperture (30) of the stator (22) and supporting the axially extending portion (20c) of the rotor (20); a casing (40) having an axially and circumferentially extending outer portion (48) surrounding said rotor (20) and having an inner surface (43); a cover plate (42) having an inner face (42i) confronting and being spaced from said second side (20b) of said rotor (20); a containment chamber (26) including said second side (34i), and said inner face (42i) of said cover plate (42) and having a top portion (45); a sump (50) within the containment chamber (26); and one or more

Abstract: An axial flux machine is provided with an integrated clutch assembly, which is housed within the bore of an annulus-shaped stator of the machine. First and second rotors, located either side of the stator are attached to the clutch basket of the clutch assembly, and rotate in unison relative to the stator. A machine housing is provided between the stator and an engagement face of the clutch basket, seated on bearings between the clutch basket and machine housing, to provide a rigid structure.

Abstract: A double-rotor single stator axial flux machine, which is supplied having no bearings between the rotors and stator internal of the machine, is mounted to an external structure such as an interface of an engine of a vehicle or a portion of the transmission of a vehicle. The machine is mounted to the structure via the shaft of the machine (on which are seated bearings located in the structure) and the stator housing. The bearings of the structure, which are external to the machine, permit the rotors to rotate relative to the stator when the machine is installed on the structure.