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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 -Radial-radial design

Inner rotor Outer rotor Stator and housing

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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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Conventional machine design

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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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A view of the novel TFM in the direction of 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!)

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Applications : Industrial drives Hybrid Vehicles Traction Renewable Energy Unconventional drives