Course content

In spite the fact that a variable speed drive will require increased investment cost, this will in most cases very quickly be balanced by large energy savings compared to fixed speed drives. Approximately 97 % of all new motors are sold without a frequency converter. This means that a large potential market exists. This course explains the energy savings potential and covers most of the commonly used types of electrical motor drives. Part I gives an overview of different type of electrical motor drives, type of loads and the impact of using mechanical gears/transmissions. In part II simplified models of the most commonly used power electronic converters are presented. Modulation methods are presented. In part III measurement techniques used in a motor drives are presented. In addition, how to choose type of controller and tuning of controller parameters are covered in details. Part IV is devoted to DC drives. Mathematical modelling is performed, analysis of steady state characteristics as well as choice and dimensioning of current- and speed-controllers. In part V a general model of AC machines are presented. This includes introduction of space vectors, coordinate transformations and transformed mathematical models. In section VI the three most commonly used AC drives are analyzed; Permanent Magnet Synchronous Motor Drives, Induction Motor Drives and Synchronous Motor Drives. It will be focus on controllers operating in a synchronous rotating coordinate system, i.e. operating with DC-quantities in steady state.

Learning outcome

The course is aiming to give a thorough understanding of converter topologies and control principles used in modern electrical motor drives.

Knowledge:
After having followed the course, the candidate shall have obtained insight in:
- rotating electrical machines and their application
- power electronic converters and their application in electrical motor drives
- common load models for electrical motor drives
- control principles for electrical motor drives

Skills:
After having followed the course, the candidate shall be able to:
- model and analyze electrical motor drives and their sub systems (converters, rotating machines and loads)
- choose a suitable rotating machine for an electrical motor drive
- choose a suitable power electronic converter structure for an electrical motor drive
- choose a suitable control structure and calculate control parameters for an electrical motor drive

Learning methods and activities

Lectures, compulsory exercises and project. The students will be divided into project groups to perform a project, in which design, analysis and simulation of a drive shall be done for a given application. The course is given in English. If there is a re-sit examination, the examination form may change from written to oral.

Compulsory assignments

• Project in groups
• Exercizes

Recommended previous knowledge

TET4110 Electrical Machines or similar knowledge. TET4190 Power Electronics for Renewable Energy or similar knowledge.

Course materials

Text books, lecture notes, manuals for simulation program.

Credit reductions