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Dept. of Electrical Energy Conversion(E2C)
• 3 full professors • 3 associate professors • 2 adjunct professors • 1 lecturer • 2 senior researchers • 3 administration staff • 15 PhD students
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Lic. och Dr. examinations at E2C
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90/91 93/94 96/97 2000 2003 2006 2009 2012
LicDr
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Laboratory for electrical motors and power electronics • 7 student benches equipped with DSP-controlled motors. • 10 test benches for PhD students and senior researchers. • Real-time simulator, climate chamber, test cell for high-speed
motor measurements, motor test rigs, mechanical workshop. • DC power supplies up to 700V, 375A or 75kW. • AC power supplies up to 760V, 470 A, 360kVA or 500Hz. • Torque balances up to 800Nm or 3750rpm. • Measurement equipment, e.g. Yokogawa power meters and Ono
Sokki torque meters.
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E2C Undergraduate Education
Electric Power
Systems
FACTS & HVDC in Electric Power
Systems
Seminars in Electrical Machines
and Power Electronics
Modulation of Power Electronic Converters
Analysis of Electrical Machines
Electrical traction
Power Electronics
Design of PM
Synchronous Machines
Electrical Machines
and Drives
Power Electronics
Hybrid Vehicle Drives
Electrical Machines and Drives
Level C
Civ. Ing. KTH year 3
Level D
Civ. Ing. KTH years 4-5International Master
Exchange
Master's degree project
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Dept. E2C.. Some selected projects
• Line start PM motors • Integral Motor • High speed motor with airgap winding • The 4-quadrant transducer (4QT) • Free Piston Energy Converter (FPEC) • Synchronous Reluctance Machines (SynRM) • High efficiency SiC 40kVA inverter
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Line-start Permanent magnet motors
permanent
magnets (PM)
squirrel cage
load, PM braking, IM quasi-static torques
speed
hybrid motor: asynchronous start but PM synchronous at steady-state
Reduced starting torque
• High efficiency • High power factor ~1 • Constant speed
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Integral motor
Features • PM design (size reduction) • Stator integrated filter coils • Small DC-link capacitor • Sensorless speed control
Advantages • Higher efficiency than
equivalent IM (for same frame size)
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PMD –High speed slot less motor
75 kW high-speed PM motor for screw compressors
Air gap winding 4-pole PM rotor
No stator teeth to reduce iron loss at 12 000 rpm
Features • Slot less design Advantages • High efficiency • Low vibrations
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The Four Quadrant Transducer (4QT)
Features • Electric gearbox with v.g.r. • Slip ring motor with an extra
PM rotor in the airgap Advantages • Stop and go function • Zero emission operation • Substantial fuel reduction • Compact design • Fast transients eliminated
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4QT –Axial-radial design
1. Double rotor machine • Axial-radial 3D-flux PM
machine • Toroidal winding • Soft Magnetic Composites
segmented core 2. Stator machine • Radial flux PM machine • Tooth winding • Isotropic laminated teeth
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Free-Piston Energy Transducer (FPEC)
• Design of linear electrical machine with following
requirements: Low movable mass (<6 kg) High power density (>1 kW/kg) High efficiency (>90 %)
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Working principles for a Transverse Flux Machine (TFM)
• Principles for a conventional machine.
• Principles for a TFM machine.
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Description of the novel TFM with global winding arrangement
• Translator wiev seen from the stator.
• Radial cross section of the novel TFM perpendicular in respect to translator motion.
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Two different magnet arrays
• Alt. 1 Translator back iron.
• Alt. 2 Halbach magnet configuration.
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SynRM : New Cost Effective GP Machine in VSD Application
• SynRM Capabilities vs. IM o High Efficiency >~ Eff1 o High Torque density o High Overload Capacity o Low shaft Temperature o Easy Production; no Cage o Adaptability:
o Same Production Line o Same enclosure o ~ Same Inverter
o Low maintenance o High Reliability o ~ Same Field-Weakening o Easy Sensor-less Control o Braking at Standstill
• PMaSynRM vs. SynRM: (SynRM + Ferrite PM)
o High Torque o High PF o High Efficiency o High CPSR
• Design and FEM Evaluation
o Fast FEM Optimization o Torque Maximization o Ripple Minimization
o Parameters Calc. (FEM) o Performance Evaluation o Skew & Ripple Analysis o Starting Torque?
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 1: Synchronous Reluctance Machine; 2: General Purpose; 3: Variable Speed Drives; 4: Permanent Magnet Assist SynRM; 5: Constant Power Speed Range.
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High-efficiency 40kVA Silicon Carbide Inverter
Div. of Electrical Energy Conversion Prof. Hans-Peter Nee
TARGET Demonstrate the potential of Silicon Carbide power devices
resulting in:
Very high-efficiency and low overall losses
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Experimental verification
Driver supplies
DSP controller
• Three-phase 40 kVA inverter
• Supply voltage 700 V DC
• Output 3x400 V (industry standard)
• Switching frequency 10 kHz
• Short-term overload capability
Efficiency at rated point ~99.7%
Free convection is enough (no fan!)