Logo Leibniz Universität Hannover
Logo: Institute for Drive Systems and Power Electronics/Leibniz Universität Hannover
Logo Leibniz Universität Hannover
Logo: Institute for Drive Systems and Power Electronics/Leibniz Universität Hannover
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Main Fields of Research

Electrical Machines and Drive Systems

Our main focus of research is on drive systems with induction or synchronous machines for industrial applications, traction applications, the generation of electrical power and on all kinds of small electrical machines and actuators. 

Key words  

  •  Time-efficient schemes for calculating the characteristics and performance of electrical machines; development of combined analytical and numerical calculation methods
  • Design and optimization of windings, especially tooth-coil windings and other fractional-slot windings
  • Calculation of electromagnetic and mechanical stresses in drive systems during transient phenomena (e.g. start-up, three- or two-phase terminal short circuits, voltage recovery, system transfer)
  • Calculation of electromagnetically excited vibrations using analytical and numerical methods
  • Analysis, prediction and prevention of parasitic effects caused by harmonics in the current and spatial harmonic fields (e.g. magnetic tones, shaft voltages, unbalanced magnetic pull, additional losses, torque oscillations) 
  • Diagnosis of defects and failures (e.g. rotor eccentricities, asymmetries within cage rotors, all types of winding defects) by use of specific measuring coils
  • Interactions between power electronic equipment and rotating electrical machines as well as system optimization)
  • System perturbations and other EMC effects in connection with rotating electrical machines
  • Prediction and prevention of bearing voltages and bearing currents
  • Time-efficient calculation of efficiency maps and loss characteristics
  • Determination and optimisation of performance characteristics, energy consumption and temperature rise in any duty cycle
  • Mechatronic systems, e.g. by use of linear direct drives
  • Novel cooling methods for drives with extremely high power density
  • Machine design that is especially suitable for sensorless position control
  • Research on micro actuators (rotating and linear motors) 

 Power Electronics and Drive Control

Our research activities comprise the application of power semiconductors, the design of power electronic systems as well as modulation and control methods for industrial drives, power systems and automotive applications. 

Key words

  • Characterisation and investigation of semiconductors (MOSFET, IGBT, SiC components) by measurements, using voltages of 3 V to 6500 V and currents of 0.1 A to 3000 A 
  • Development of gate drives for IGBTs, e.g. with digital signal processing and condition monitoring
  • Analysis, design, calculation and optimum dimensioning of power electronic circuits from the electrical and thermal point of view
  • Design and investigation of converters with novel SiC semiconductors for industrial and automotive applications 
  • DC/DC converters, e.g. for fuel cell systems for decentralised power generation 
  • Novel modulation methods for voltage source inverters with low pulse rate (e.g. SB-ZePoC) 
  • Control of modular multilevel converters (e.g. MMC, MMMC)
  • Concepts for medium-voltage converters for connecting battery storages to medium-voltage grids 
  • Control concepts for wind generation plants in the MW range 
  • Highly dynamic control of generator/converter systems with islanding capability 
  • Drive control for highly dynamic drives with sinusoidal output filters and very low switching frequencies 
  • Encoderless control of synchronous machines at low speed down to zero speed
  • Drive systems for electric and hybrid vehicles