Abstract: Described herein is a method of cooling a plurality of power devices, where the power devices are arranged as a plurality of switches used to generate a three-phase output AC voltage. Based on power device stress data, one or more switches (associated with one or more phase output AC voltages) may be identified as requiring more cooling than other of the switches. The switches are controlled to apply a common mode component voltage to each of the three phases for at least a portion of one or more output AC voltage segments. The common mode component voltage has a maximum amplitude that is sufficient to clamp the phase AC output voltage of the identified phase(s) to the positive supply rail voltage and/or negative rail supply voltage when the respective phase AC voltage is approaching respectively the positive supply rail voltage or negative supply rail voltage to cool the identified switch(es).

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: A modulation technique is described in which a controller modulates the output AC voltages to introduce an offset to the phase that is most positive or most negative such that the phase is clamped to the +dc supply when the respective phase is most positive and to the ?dc supply rail when most negative. The offset is provided by introducing a common mode component voltage to all of the phases over a plurality of output angle segments. In order to reduce the Noise Vibration and Harshness (NVH) and EMI, the common mode component voltage amplitude is varied over the output angles within the respective segment between a minimum and a maximum in order to control a slew rate of the rising or falling edges of the three phase AC output voltages.

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: An axial flux machine is described. The machine has a stator comprising a stator housing enclosing a plurality of stator bars disposed circumferentially at intervals around an axis of the machine, and a rotor comprising a set of permanent magnets and mounted for rotation about the axis of the machine. The rotor is spaced apart from the stator along the axis of the machine to define a gap between the stator and rotor and in which magnetic flux in the machine is generally in an axial direction. The machine also comprises a hub assembly comprising a rotating hub and a mount separated by a bearing to permit the hub to rotate relative to the mount, the rotating hub comprising a hub flange and the mount comprising a mount flange, each of the flanges being spaced axially apart from one another. The machine further comprises a bulkhead for mounting the hub assembly and stator, wherein the bulkhead is mounted to the mount flange of the hub assembly and the stator housing is mounted to the bulkhead.

Abstract: An axial flux machine (100) is provided, in which the rotor (104) is cooled via air cooling, provided by impeller blades (140) located on the opposite side of the rotor (104) to the stator (102). An impeller cover (142) covers the impeller blades (140) such that air channels are defined between adjacent blades. The air channels have an air inlet (146) at an inner radial portion of the rotor (104), and an air outlet (146) at the outer radial extremity of the impeller blades (140). As the rotor (104) turns, the air is drawn through the air channel from the air inlet (144) to the air outlet (146). The motor (100) may be enclosed within a housing (120), in which case air ducting (150,152) may be used to guide air to the air inlet (144), and from the air outlet (146) to the outside of the housing (120).

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: We describe a method of manufacturing a stator of an axial flux permanent magnet machine, the machine having a stator comprising a stator housing defining a chamber comprising 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: providing first and second radial walls for said stator housing; providing inner and outer side walls for said stator housing; assembling said first and second radial walls and said inner and outer side walls around said set of coils to form a stator assembly, wherein said assembling further comprises: providing one or more collapsible elements between said side walls and one or both of said first and second radial walls; and attaching said

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: We describe a method of manufacturing a housing for the stator of an axial flux permanent magnet machine, in particular a Yokeless and Segmented Armature motor, the machine having a stator comprising 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.

Abstract: We describe a method of manufacturing a housing for the stator of an axial flux permanent magnet machine, the machine having a stator comprising 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: fabricating a radial wall for said stator housing to be located in said gap between said rotor and said stator by: placing a resin membrane into a mold of an injection molding machine; injection molding a set of reinforcing features onto said membrane using a thermoplastic polymer bondable when molten with said resin; and manufacturing said housing using said radial wall.

Abstract: There is provided an axial flux motor comprising one or more rotating disks (10) and a stator (20) comprising a cavity (30) formed between walls (40a, 40b) and containing therein more than one electro-magnetic coil assembly (50). Each electro-magnetic coil assembly (50) comprises more than one pole piece (60), each having an axially extending shank portion (70a) and first and second radially extending end shoes (72a, 72b) and one or more associated coils (55), each of the one or more associated coils (55) being wound around a shank portion (70a), wherein said outer surface (75) of said end shoes are preferably joined to one or other of said walls (40a, 40b).