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In the industrial, domestic, transport and energy sectors the use of electric motors powered at constant voltage / current and frequency is rapidly decreasing, with correspondent increase of application of static power converters in drives with high performance in terms of efficiency and dynamics. The course provides the basic notions of electrical machines, converters and the main drive management techniques in the context of the main applications.
The course aims to provide skills on the most common types of electric drives and their interactions with power supply / load, focusing in particular on their functionality, the main technical issues and the selection criteria in the system design phase.
Basic knowledge of the operating principles of electrical machines and static power converters and their models, for application in the context of electrical drives.
Ability to carry out simple general assessments for the choice of the type of converter and motor with a certain mission profile, ability to model the individual components and to carry out simple quantitative assessments on the electromechanical quantities at the ports.
Basic knowledge of circuit theory: solution of first order circuits in the time domain, circuits in sinusoidal steady state, symmetrical and balanced three-phase systems.
Basic knowledge of Electronics.
Theoretical lectures, supplemented by numerical exercises.
General information on electrical machines: generators, motors, transformers. Thermal issues. Principles of operation, ferromagnetic core, windings.
Single-phase transformer: model in sinusoidal steady state. Three-phase transformer: single-phase equivalent circuit. Examples of morphologies, sizes, applications.
Three-phase induction motor: single-phase equivalent circuit. Static speed-torque characteristic. Examples of morphologies, sizes, applications.
Synchronous machine: single-phase equivalent circuit. Examples of morphologies, sizes, applications.
DC motor: equivalent circuit. Static speed-torque characteristic: separate excitation and series excitation. Universal motor.
General information on the static conversion of electricity, notes on semiconductor devices.
Switching converters (dc-dc step-down, step-up, bridge, voltage source inverters (single-phase, three-phase, multilevel), modulation.
Natural commutation converters. Diode rectifiers. Controlled rectifiers, bidirectional rectifiers, cycloconverters, current source inverters and synchro-converters.
Conversion quality: reactive power and harmonics.
General information on electric drives. Quadrants of the voltage-current and torque-speed plane, electric braking, speed-torque characteristics.
Drives with direct current motors, speed regulation with constant excitation.
Drives with induction motors. Constant flux speed regulation. Outline of field-oriented control and vector control.
Drives with synchronous motors, with voltage source inverter and with cycloconverter, with current source inverter.
Outline of other drives (with SRM, with reluctance motors, with stepper motors).
For further information:
S. Chapman, Electric Machinery Fundamentals, McGraw Hill Education (ISBN 0073529540)
Erickson, Maksimovic: Fundamentals of power electronics, Kluwer Academic Pub (ISBN 0792372700)
Bose: Power electronics and motor drives: advance and trends, Academic press (ISBN 0120884054)
MASSIMILIANO PASSALACQUA (President)
LUIS RAMON VACCARO (President)
All class schedules are posted on the EasyAcademy portal.
Written exam: numerical problem on an electric drive.
Oral exam: free exposition on a topic of the course selected from a fixed list.
For the written test, correct solution of the numerical problem (up to 20/30)
For the oral exam, correct framing of the problem, clarity of presentation, ability to synthesize (up to 11/30).
Final grade equal to the sum of the two above.