SOFT MAGNETIC COMPOSITES FOR ELECTRICAL MACHINE APPLICATIONS
SOFT MAGNETIC COMPOSITES FOR ELECTRICAL MACHINE APPLICATIONS Alan Jack, Barrie Mecrow, Glynn Atkinson, Bogi Jensen University of Newcastle upon Tyne [email protected] Newcastle Drives and M achines Group An SEM picture of SMC powder Newcastle Drives and M achines Group Parts Production 1 Powder 2 Compaction 3 Heat treatment Newcastle Drives and M achines Group B-H curves 1.8 B (T) Other SMC properties: 1.6 1.4Density 7.54 g/cc (solid steel = 7.85) 1.2 Transverse rupture 1 strength = 83MPa – 0.8 weak 0.6Conductivity = 384 0.4 S/m (solid steel = 0.2 5x106) 0 Thermal conductivity oC – 100 10 20W/m/ same as laminations H (A/m) Somaloy 700 3p EN 10106 (M330 35A) 0.5mm polycor 1000 10000 Newcastle Drives and M achines Group Iron Loss: SMC 5mmx5mm sample - lams manufacturers data Iron loss at 50Hz Iron loss at 100Hz 100.0 1.0 0.1 1.0 10.0 Loss (W/kg) Loss (W/kg) 10.0 Somaloy 700 3P M330 35A 0.5mm polycor 0.1 10.0 1.0 0.1 0.1 B (T) B (T) Iron loss at 400Hz Iron loss at 200Hz 100.0 Loss (W/kg) Loss (W/kg) 100.0 10.0 1.0 0.1 1.0 10.0 1.0 1.0 B (T) 10.0 0.1 1.0 10.0 B (T) Newcastle Drives and M achines Group 10.0 Properties (45id 55od x 5mm ring) Core loss @ 1T [W/kg] Material Resistivity TRS [MPa] [µΩm] B@ 10kA/m [T] µmax 100 Hz 400 Hz 1 kHz Somaloy 700 1P 400 40 1,56 540 10 44 131 Somaloy 700 3P 200 125 1,61 750 10 46 137 Latest development 700 60 1,57 600 6 32 104 Newcastle Drives and M achines Group Compared with laminations:– good bits Isometric properties – 3D flux Net shape – no extra operations Tight tolerance – can fit core sections together with no magnetic effect Smooth surface finish – minimises insulation requirements Newcastle Drives and M achines Group Compared with laminations:– bad bits Poorer magnetic properties Low mechanical strength and brittle Practical limits on shapes which can be pressed e.g. 6:1 aspect ratio More expensive than a laminated stack Newcastle Drives and M achines Group Permanent Magnet Machines Magnetic circuit is dominated by the magnets Servo motors - Mk 1 ICEM 1996 Newcastle Drives and M achines Group Coils are die compacted – same Mk from 2 pressure effect impregnation Separately wound, high fill, bobbin coilsto slot area 78% copper IEEE IAS 2000 Newcastle Drives and M achines Group Mk 3 style of construction Allows radial tooth compaction keeps teeth press-able IEE PEMD 2004 Newcastle Drives and M achines Group Comparison with laminated single tooth winding m/c laminated SMC Shorter, fatter teeth make copper shorter for the same tooth area = 20% reduction 20% shorter allows 20% smaller copper area for the same resistance = 36% less copper volume Slot area is 17% smaller in SMC case – but 20% less copper area Machine is shorter - 30% Newcastle Drives and M achines Group Compressor motor Teeth simply butt-jointed to core back impregnated in prototype but aimed at over-moulding Newcastle Drives and M achines Group Shorter Less copper More iron loss Efficiency about 2% lower Efficiency should be higher with latest materials Newcastle Drives and M achines Group Two part IEE PEMD 2004 Three part Cutting down the no of parts to keep the cost down Newcastle Drives and M achines Group BLDC Radial flux motor Producer: ABB Application: Industrial servo motor Benefits • Reduction of manufacturing costs • More compact (33% shorter) • Lighter • Improved performances (25% lower inertia, lower losses) Somaloy® stator component Newcastle Drives and M achines Group BDC ABS Motor – Aisin Seiki Co., Ltd Axially extended tooth tips use magnet better 36 % Offset core back provides room for internal commutator Shorter machine allows 1 less bearing Weight Weight Conventional ABS Motor 17 % New Type of ABS Motor Over-moulded plastic (light blue) provides ground wall insulation and mounting of stator on splined Newcastle Drives and M achines Group shaft Courtesy LAING GmbH, BLDC Pump Motor – Laing GmbH: Germany • Patented spherical motor design • Single and self-adjusting ceramic bearing • Mostly water film bearing self pumped • Rotor/Impeller the only moving part Centrifugal pump wheel Permanent Magnet rotor Ceramic bearing Stator and Controller Newcastle Drives and M achines Group Axial flux motors are difficult to laminate - real opportunity for SMC SMC + Laminations “strip” core back “rolled up” holds teeth Newcastle Drives and M achines Group Modulated Pole Machines e.g. IEEE IEMDC ‘97 Transverse flux & claw poles •Modulate two poles into many All poles see all the current high electric loading •High torque/unit volume •High frequency IEE PEMD 2002 •Not easy to laminate •Two pressings and a simple hoop coil Newcastle Drives and M achines Group Claw pole stepping motor actuator 2-Phase Claw pole stator Newcastle Drives and M achines Group Courtesy Lyng Motor, Motor, Norway Claw pole armature machines from Hitachi Japan First motor aimed for air moving home appliance application, start of production mid 2009 Half the axial length An efficiency improvement of 5% Easy Recycling Easy assembly Lower cost Newcastle Drives and M achines Group Latest thoughts high torque (13.5Nm/kg) good reactance - 0.92pu looks rather promising Newcastle Drives and M achines Group Actuators: Bosch diesel injector solenoid valve Newcastle Drives and M achines Group Flux in radial/axial plane – laminations in axial/radial plane – implies varying thickness Moving Magnet—existing commercial laminations….. designs Only not east to get coil in→either…. magnet moves very light mover Easy in SMC Magnetic Permanentcircuit magnetnot - low permeability not a well used problem Linear tubular motors for pumps core magnet Coil in this space Newcastle Drives and M achines Group Linear Compressor – Twinbird Corporation: • Free Piston Stirling Cooler (FPSC) – FPBC TB-40 •Similar performance as laminated • Easier assembly and cheaper • Reduced weight and noise Up to -120°C SMC Inner stator Permanent magnet SMC Outer stator Coil Newcastle Drives and M achines Group Courtesy Twinbird Corporation, Japan Other possible toplogies e.g. Buried magnet style Simpler magnets, strong mover, better magnetic circuit But heavier mover Newcastle Drives and M achines Group magnet moving One buried magnet Lots of new design ideas possible! Newcastle Drives and M achines Group Conclusions SMC properties getting better B-H, coercivity & resistivity More known of features but more needs to be known SMC allows new design and production freedoms - advantage if design is right Cost of part manufacture crucial – pushing applications away from conventional shapes BH (saturation & permeability) not a show stopper for permanent magnet machines or for some chokes Newcastle Drives and M achines Group
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