Power Electronics and Electrical Drives

 

Electric Railway Drives (for electrical and mechanical engineers) [de, WS]

In this lecture, the systematics of electric railroad drives for DC and AC railroads as well as for railroads with diesel-electric drives is explained. The different requirements for high-speed traction units on the one hand and local transport vehicles on the other hand as well as their effects on the realization of the respective drives are elaborated. The development of low-feedback rectifiers and inverters for the operation of rotating field machines is shown. Detailed explanations of the applied chassis technologies with regard to the lowest possible unsprung masses and the cornering ability of low-floor vehicles follow. Measures to reduce the specific energy demand of rail vehicles are also discussed.

Further information on the lecture: RWTHonline

 

Power Electronics - Control, Synthesis and Applications (CSA) [en, WS]

Power electronics generally has the goal to perform electrical energy conversion at high efficiency. The course focuses on the following aspects of converter design:

  • Minimum converter losses
  • Silicon and magnetics losses
  • Thermal design
  • Soft switching of silicon devices to improve device ratings
  • Using snubbers
  • Soft-switching converter topologies
  • Galvanically isolated dc-dc converters
  • Transformers in power electronics, using uni- and bidirectional core excitation
  • AC-AC converters
  • Control of voltage source converters
  • High-power electronics
  • Examples

Further information on the lecture/exercise class: RWTHonline

Further information on the revision course: RWTHonline

Further information on the laboratory exercise class will be announced in the lecture or alternatively in the L2P-learning room.

 

Power Electronics - Fundamentals, Topologies and Analysis (FTA) [en, WS]

Power electronics deals with control and efficient conversion of electric energy by means of power-electronic switches. Areas of application are e.g. automotive electric propulsion and power systems, distributed generation using wind turbines, solar converters or fuel cells, battery systems, industrial drives and induction heaters, as well as utility-scale power flow control and DC transmission systems. The course first presents modes of operation and topologies of line- and self-commutated converters. Line-commutated converters, switching at the frequency of the connected single or three-phase system, are introduced discussing important applications such as two-way rectifiers and cycloconverters. A separate section is dedicated to harmonic distortion. Self-commutated converters such as DC/DC topologies and voltage or current source inverters are analyzed, with a special focus on various control concepts, e.g. current control and pulse-width modulation (PWM). A manuscript is available. The lecture is held in English.

Further information on the lecture/exercise class: RWTHonline

Further information on the revision course: RWTHonline

Further information on the laboratory exercise class: RWTHonline

 

Power Semiconductor Devices [en, WS]

  • Basics of semiconductor physics: Production process of silicon, Zone melting for n-doped silicon, Doping processes, Repetition of the basic equations on carrier transport and generation
  • PN junction: Structure, Thermal equilibrium, Schottkys parabola approximation, Field and diffusion currents, Boltzmann equation, Diffusion voltage, Space charge zone, Behavior at low-level injection, Blocking operation, Performance and blocking capability
  • PSN Structure: On-state behavior at low- and high-level injection, Blocking operation, Voltage limits, Characteristic curves
  • Dynamic behavior of power electronic diodes: Turn-on processes at low- and high-level injection, Turn-off processes, Transition from on-state to blocking, Transition with snubber circuit
  • Thyristor: PNPN structure, Basic equations, Equivalent circuit, Switching characteristic, Blocking characteristic
  • Further thyristor-based structures: Reverse-conducting thyristor, GATT, Triac, GTO
  • MOSFET: Structure, Basic equations, Construction principle, Characteristic curves, Dynamic behavior, CoolMOS (superjunction)
  • Modern Devices: Devices with combined bipolar and MOSFET-structure (IGBT, GCT, MTO, MCT)
  • Thermal characteristics of semiconductors: loss balance, thermal resistances, cooling, damage by power cycling

Further information on the lecture: RWTHonline

 

Basic Areas of Electrical Engineering 2 [de, SS]

Professor De Doncker holds this basic lecture for first-year students since the summer semester of 1999. Following a repetition of mathematical fundamentals, the lecture introduces complex ac calculus. In addition, discrete elements like Resistor, Capacitor and Inductor are explained. The transformer is introduced as an element consisting of two magnetically coupled coils. An own section is devoted to the topic of multi-phase systems focusing in particular on the generation of such systems. Subsequently, the three-phase transformer is introduced. The lecture concludes with nonlinear components, circuits and switch-mode power supplies. Great care was taken to organize the course with respect to didactics. Students recognize this regularly with outstandingly good ratings within the faculty's quality management process. The whole lecture uses data projection. Photos, animations and videos are used in order to illustrate lecture contents. Demonstration experiments during the lecture make a connection between theory and practice. Manuscripts are offered for both, the lecture and the practical instruction class. Students gather individual feed-back in small-group practical classes and a test exam.

Further information on the lecture: RWTH-Online

 

Electric Local Transport Systems [de, SS]

In this lecture, Prof. Müller-Hellmann will talk about recent developments in the field of mass transit systems. Here, questions of technology as well as questions of management are dealt with. The legal framework for the technology, the operation and the financing are comprehensively explained. In an overview urban transport systems and vehicles such as trams, urban, underground and suburban trains as well as novel driverless systems are presented. Basic considerations such as daily peaks and the highest possible utilization of the trains are explained and solution concepts are discussed. In addition, issues of energy supply and safety aspects of electric transport systems are dealt with. As a rule, an excursion to a local transport company completes the lecture.

Further information on the lecture: RWTH-Online

 

Seminar: Electromagnetic Noise in Power Electronics [en, WS+SS]

In this module, fundamentals, modelling concepts and mitigation techniques for high-frequency emissions of power electronic systems are presented in theory and practice. With the ongoing trend of replacing silicon devices with fast-switching, wide-bandgap semiconductors (e.g. SiC, and GaN), interference mitigation techniques to ensure reliable operation becomes more important.

In a first day, master students will learn theoretical and practical solutions for the modelling, measurement and suppression of interference in power electronic systems with presentations and simulation exercises. On a second date, laboratory experiments are carried out in groups of maximum five students to measure the emitted interference and the interference suppression of power electronic systems.

Further information on the lecture: RWTHonline