Aim
The aim of the course is to give an orientation on the characteristics of modern active and passive components that are used in power electronic converters. The course also gives an understanding of the function of power electronic converters like AC/DC-converters, switched mode power supplies, frequency converters for motor control, and high voltage DC-transmission (HVDC).

The course gives knowledge on the control of power electronic converters in general and also in special applications where power electronics is used, like electromechanic drive systems, rotating electric machines, linear motors, loudspeakers and so on. Power electronics in power system applications is another area which is treated in the course, where active net filters and transistor based HVDC are investigated. There are also two projects, aiming at giving an active knowledge in simulations, experimental work, and evaluation of circuits and systems within the area of power electronics.

Knowledge and understanding
For a passing grade the student must

• be able to analyze and understand power electronic circuits;

• be able to analyze modulation methods (carrier wave and tolerance band) for power electronic converters;

• be able to analyze models of electrical machines suitable for deriving current, torque and speed regulators.

Skills and abilities
For a passing grade the student must

• be able to estimate the semiconductor losses in switched power electronic converters;

• be able to formulate models of electrical machines suitable for deriving current, torque and speed regulators;

• be able to derive and implement current, torque and speed regulators for electric drive systems in digital signal processors.

Judgement and approach
For a passing grade the student must

• select components for power electronic converters based on current and voltage level sand switching frequency;

• estimate the characteristics of an electric drive system in comparison with other, non-power electronic alternatives.

Contents

• Lectures: Switch mode power supplies, principle of forward and flyback operation. Rectifiers and inverters. Modulation of power electronic converters. Control of power electronic converters. Electrical machines. Based on dynamical models of electrical machines and modulation methods for power electronic converters, control systems for position, speed, torque, flux, and current are developed. Grid connected converters: active filters, HVDC transmission and transistor based HVDC transmission. Renewable energy systems. Devices: diodes, bipolar power transistors, field effect transistors (MOSFET), insulated gate bipolar transistors (IGBT), thyristors, gate turn-off thyristors and passive components used in power electronic circuits. For the components, the properties, limitations, drive and protective circuitry, are discussed. Loss-estimation and cooling of power electronic devices and equipment.

• Simulations: Analysis of the components and parts of the switch mode power supply and transistor full-bridge converter also examined experimentally in the laboratory. The simulation program used is a commercially available power electronics simulation package;

• 6 home assignments containing calculus and simulation work covers the course curricula regarding electrical machines and control of electrical drives. The exercise hours are used for supervision of the home assignments;

• Laboratory work: Practical aspects of power electronic control of electrical drives are emphasized in numerous laboratory sessions and simulation exercises. Experimental validation of the operation of a switch mode power supply and a transistor full-bridge converter;

• Project: One report on practical aspects of electrical drives including results based on the home assignments. One report on the simulation and the experimental laboratory work on the switch mode power supply and the transistor full-bridge converter. Written and oral report.

Literature
Alaküla M, Karlsson P: Power Electronics – Devices, Circuits, Control and Applications, IEA, LTH.