Targets and contents of the course

The course gives the students the basic dictionary of the electrical drive. They  will learn to compare the functional performances in relation with the different market segment, and to choose different components from manufacturer catalogues. In order to reach this target the operating condition and the control features of different electrical drive will be analyzed, underlining the main constituting elements: the electrical motor, the power converter, the control algorithm and the power supply system. Furthermore different applications will be analyzed both in industrial and in transport field.

Description of the main topics

General structure of an electrical drive. Identification of the nameplate data for the drive and for its main components. Criteria to choose the components for an electrical drive, thermal operating point. Calculation and meaning of the RMS torque. Case studies in the field of both industrial and transportation application.

Static power conversion. Description of the main power semiconductor devices. Analysis of different power converter and of the different way for power conversion; rectifier (AC/DC conversion), inverter (DC/AC conversion), chopper (DC/DC conversion). Analysis of the control techniques and modulation for the proposed converters. Energy analysis in industrial and transportation drive.

DC motors. The DC isotropic machine. Real structure. Operating characteristic, operating field (variable tension), the commutation, the dynamical model.

Synchronous motors. The rotating magnetic field for bi-phase and three-phase systems. The synchronous isotropic machine: general structure and operating characteristic. Operating field with fixed supply voltage (from the grid) and with variable supply voltage (through inverter). Isotropic synchronous machine with permanent magnets: dynamical model.

Induction motors. The induction motor: the equivalent circuit. Operating modes: mechanical characteristic, startup with fixed supply voltage. Operating field both with fixed and variable supply voltage.

Control of electrical machines. Control scheme for DC motor. Closed loop control for current/speed/position regulation. Use of chopper for DC motor control. Permanent Magnet Synchronous Motor (PMSM): control scheme for field oriented control through inverter. Induction Motor (IM): voltage/frequency scalar control, field oriented control scheme through inverter.

Case studies: application of electrical drives and industrial controllers . Electrical drive for hybrid/full electric vehicle application. Configuration of electrical drive for railways application. Industrial application: servomotors and bi-directional converters. Common programming languages for industrial controllers: CoDeSys.

Organization of the course and method of verification

The course has a balanced structure of lessons and exercises. The Assessment of the course content will be made through a final oral test. During this test particular attention will be paid also on the results of the practical exercises.