


Politecnico di Torino  
Academic Year 2017/18  
03IJHLX Fundamentals of electrical drives 

1st degree and Bachelorlevel of the Bologna process in Electrical Engineering  Torino 





Subject fundamentals
For what concerns the control theory part, goal of the course is to provide students with basic knowledge on dynamic systems analysis and on simple control system design for linear time invariant continuous time systems described in terms of state variables and transfer function.
In the second part of course the direct current electric drive will be analyzed, taking into account the control loops design. 
Expected learning outcomes
Ability to study linear dynamical systems described in state variable form analyzing stability, controllability, and observability.
Ability to design simple feedback control systems for SISO systems. The acquired knowledge and understanding capabilities will allow to understand the behavior of direct current electric drives. The applying knowledge and understanding capabilities will allow to design simple controls for direct current electric drives. 
Prerequisites / Assumed knowledge
Basic knowledge of electric circuits, electrical machines and applied mechanics is required.

Contents
 Dynamic system description in state variable form and in transfer function form. (4 h)
 Time response of dynamic systems. The transition matrix. (2 h)  Stability for linear dynamic systems. (2 h)  Controllability and observability of dynamic systems and relevant canonic forms. (2 h)  State feedback. State observer. (6 h)  Open loop and closed loop control. Bode and Nyquist plots. Stability of closed loop systems: the RouthHurwitz criterion and the Nyquist criterion. (7 h)  Transient response and steady state response of dynamic systems. Time and frequency domain specifications. Attenuation of additive and parametric disturbances. (5 h)  Feedback control design based on the Bode plot of the open loop transfer function. (14 h)  Definition of electric drive. General structure of electric drives (3 h).  Electric drives for spindle and axis applications (3 h).  Hard magnetic materials and their application in electric motors (4 h).  Safe operating area (magnetic and thermal limits) of servomotors in the T, omega plane (4 h).  Dynamic model of the d.c. motor (5 h).  Torque control for d.c. motors (5 h).  Speed control for d.c. motors (5 h).  Analysis of d. c. servomotors characteristic by data sheets (5 h).  Speed and position transducers: tacho generators (3 h).  Analysis of the torque ripple and mechanical resonances (3 h).  Test of d.c. electric drives (2 h). 
Delivery modes
Lab tutorials should enable to get basic knowledge of a modern program (MATLAB) for analysis and design of control systems. With the aid of such program students can carry on exercises similar to those developed in class lectures and tutorials, but they can also work out more complex problems that could hardly be developed without the aid of a computer.
Numeric exercises related to control loop design will be carried out during the course. 
Texts, readings, handouts and other learning resources
1. P. Bolzern, R. Scattolini, N. Schiavoni, Fondamenti di controlli automatici, McGrawHill (in Italian)
2. K. Ogata, Modern control engineering, PrenticeHall, London. 3. R. C. Dorf, R. H. Bishop, Modern control systems, AddisonWesley Reading, Ma. For further insights it is possible to refer to the following texts:  N. S. Nise, Control systems engineering, The Benjamin/Cummings Publishing Co., Redwood City, CA.  G. F. Franklin, J. D. Powel, A. EmamiNaeini, Feedback control of dynamic systems, AddisonWesley Reading, Ma.  B. C. Kuo, Automatic control systems, PrenticeHall, London.  J. J. D'azzo, C. H. Houpis, Feedback control system analysis & synthesis, Mc Graw Hill, New York. 4. Ion Boldea, S.A. Nasar; 'Electric drives'; CRC Press 5. Werner Leonhard; 'Control of electrical drives'; Springer 6. Hans Groß, Jens Hamann e Georg Wiegärtner; 'Azionamenti elettrici di avanzamento nell'automazione industriale: fondamenti, calcolo, dimensionamento'; Tecniche Nuove (in Italian) 7. L. Olivieri, E. Ravelli; 'Principi ed applicazioni di elettrotecnica'; CEDAM (in Italian) 
Assessment and grading criteria
Written test followed by an oral exam.
Written examination:  The exam consists in a 3hour test conducted in the Lab with Matlab available.  The exam consists of two exercises, one on the design of feedback compensators and the other on the analysis of dynamic systems described in state variable form. Oral examination Questions concerning electrical drives and related to the course program. The number of questions is generally between 1 and 3. 
