University of New South Wales School of Electrical Engineering & Telecommunications ELEC ELECTRIC DRIVE SYSTEMS.

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1 Aims of this course University of New South Wales School of Electrical Engineering & Telecommunications ELEC ELECTRIC DRIVE SYSTEMS Course Outline The aim of this course is to equip students with knowledge of variable-speed drives and motion control systems which are used in many industrial processes such as in conveyors, machine tools, pumps, compressors, mining drives, electric vehicles, ship propulsion, wind energy systems, aircraft actuators, servo drives and automation systems, to name a few. The course stresses the basic understanding of characteristic of machines driven from appropriate power electronic converters and controllers. Steady-state torque-speed characteristics of drives driven by power electronic converters, representation of drive dynamics, and design drive control systems will be covered. Student Learning Outcomes and Graduate attributes At the conclusion of this course, the students will be able to: 1. understand fundamental elements of drive systems, analyse the steady-state characteristics of a few commonly used types of drives used in the industry. 2. understand the performance of these drives supplied from appropriate converters. 3. be able to select and design important elements of a drive system. 4. understand the quadrant operation of various types of drives and their control requirements, selection of converters, components, etc. 5. understand how to design the hierarchical control structures for drive systems. 6. be able to apply the theories of electrical machines, power electronic converters and control system design to implement drive systems which are appropriate for certain specific applications requiring adequate performance. Brief Syllabus: Elements of drive systems; requirements of industrial drives. Drive representation, quadrant operation, dynamic and regenerative braking. DC motors, converters for DC motor drives, performance analysis. Performance analysis of synchronous motor drives with variable voltage or current source and variable frequency supply. Performance analysis of induction motor drives with variable voltage or current source and variable frequency supply. Field oriented (or vector) control of synchronous and induction motor drives; Computer aided design. Course Webpage: All lecture notes, assignments, tutorial and laboratory sheets for this subject can be found on the school webpage, via Current Students Study Notes Lecture Notes. You may have to enter username: (your student number) and password: ee&tview to access the webpage for this course. Students will be expected to bring the printed lecture notes, tutorial or laboratory sheets into the lecture/tutorial room or laboratory, as appropriate. They are also expected to visit ELEC4613 Course Outline 1 F. Rahman

2 this site regularly to keep up-to-date on Lecture Notes, Tutorial and Laboratory sheets, announcements of mid-session test/ assignment, and other information related to this course. Lecture Content/Schedule There will be three hours of lecture per week. The total number of lecture hours over the 12-week session will about 30, the remaining 6 hours will comprise of problem solving/tutorial/computer modelling sessions in lieu of formal lectures. The third hour of lecture in even weeks will be used for these sessions. Lecture notes are available from the course Lecture Notes webpage. Course Content Hours 1. Introduction to Electrical Drives 3 Rotational Systems, Load couplings, representation of torque referred to motor and load shafts; Energy relationship. Quadrant operation Steady-state and dynamic operation 2. DC motor drives 4 Review of DC motors and characteristics Switched-mode PWM converters. Single- and three-phase thyristor converter circuits. Analysis of converter and DC motor circuits. Effects of discontinuous conduction on drive. 3. Brushless DC drives 2 BLDC machine fundamentals; Analysis of machine back emf and torque; Ideal back-emf and current waveforms, Sensor requirements 4. Synchronous motor drives 6 Review of synchronous motors and characteristics Salient and non-salient pole machines; Reluctance motors Performance under Voltage Source Inverter (VSI) drive Performance under Current Source Inverter (CSI) drive Operation with maximum torque, field-weakening and Unity power factor. 5. Induction motor drives 6 Drive characteristics using equivalent circuit representation Performance with variable-voltage and rotor power Static Scherbius drive Characteristics with VSI-VF inverter and CSI-VF drive Effect of harmonics on drive performance 6. Machine representation in orthogonal axes 6 Representation of machine dynamics; Stator, synchronous Rotor reference frames. General orthogonal set; representation of AC machines in orthogonal reference frames. Representation of synchronous machine dynamics in the ELEC4613 Course Outline 2 F. Rahman

3 stator and rotor reference frames; d- and q-axes currents and fluxes; rotor flux oriented control (RFOC). Representation of induction machine dynamics in the stator and synchronously rotating reference frame; Condition for alignment of the direct-axis with rotor-flux axis. Indirect rotor-flux oriented control (RFOC) structure; effect of rotor time-constant on RFOC. 7. Controller design for electrical drives 3 Role of various control loops in drive systems; drive system damping; torque, speed and position control loops; hierarchy of control loops; Typical controllers; design considerations for each control loop. Total hours 30 Staff Contact Details Course Name Location Phone Convener & Lecturer F. Rahman f.rahman@unsw.edu.au EE Tutor F. Rahman f.rahman@unsw.edu.au EE Lab in-charge G. Liyadipitiya gamini@unsw.edu.au EE119 NA Tutorial Tutorial sheets are available on Moodle for this course. Tutorial classes will start in week 2. Solution of all tutorials will be posted on the course webpage progressively, sometime after the material for each tutorial has been covered in tutorial class. Laboratory The laboratory for this course consists of four experiments, E1 E4, which will be conducted in room EE119. There are two laboratory sets for each experiment. A maximum of two students can be accommodated for each set. Laboratory will start in week 3 or 4 for students enrolled in even and odd weeks, respectively. Laboratory sheets are available from the course website. Students are required to read the School Safety Manual for Laboratory and Laboratory Safety Instructions for Laboratory for this course, and submit the signed Laboratory Safety Declaration form to the lab supervisor before they start the first laboratory experiment. Laboratory experiments: Experiment E1. Speed control of a DC motor with an inner current loop In this experiment, the speed of a DC motor will be controlled by using a pulse-widthmodulated (PWM), four-quadrant, H-bridge switching amplifier. An inner (minor) current loop is used to control the torque continuously and an outer speed loop is used to reduce the speed error. ELEC4613 Course Outline 3 F. Rahman

4 Experiment E2. Brushless DC Drive This experiment introduces you to a brushless DC motor drive which has permanent magnet excitation in the rotor, and has as the armature a 3-phase winding which is supplied by a three-phase inverter. The armature windings are supplied from the inverter; these are switched autonomously by Hall sensors mounted on the rotor. The amplitudes of the motor currents are regulated by PWM duty cycle control of the inverter. In this way, the motor develops torque which is proportional to the amplitude of the motor current, which is the hallmark of a brushed DC machine, with requiring a commutator-brush assembly. Experiment E3. V/f and rotor flux oriented (vector controlled) induction motor drive This experiment helps you to study and compare the performance of a three-phase induction motor driven from a voltage source variable frequency supply (V/f) and with a rotor flux oriented controllers (RFOC). With V/f control, the voltage to frequency ratio of the supply is kept nearly constant. This method is based on the steady-state equivalent circuit of the motor. With RFOC, three-phase currents supplied to the motor are first resolved into two quadrature current sources which independently regulate the torque and rotor flux linkage of the motor. The quadrature currents, i d and i q, are expressed in the synchronously rotating reference frame. The particular topics of interest in this experiment are the control characteristics for torque and flux of the motor under RFOC and comparison of the dynamic performance of the drive supplied from the V/f supply. Experiment E4. V/f and rotor flux oriented (vector controlled) synchronous motor drive This experiment helps you to study the performance of the three-phase PM synchronous motor driven with variable-voltage, variable-frequency (V/f) and rotor flux oriented controlled (RFOC) current-source inverters. In the constant V/f scheme, the applied per-phase RMS voltage to the motor is made proportional to the applied frequency using a PWM VS inverter. With current-source drive, three-phase currents supplied to the motor are first resolved into two quadrature current sources which independently regulate the torque and rotor flux linkage of the motor. The quadrature currents, i d and i q, are expressed in the rotor reference frame. The particular topics of interest in this experiment are the control characteristics of torque and flux of the motor under V/f and RFOC and comparison of the dynamic performance of the drive with the two control schemes. Mid-session Test There will be one Mid-session Test (closed-book) in week 7. It will consist of numerical problem solving and descriptive parts based on material covered up to week 6. Time and location of the test will be announced in due course. This test will be held under normal examination-like conditions. Mark scored in this test (out of 10) should be indicative of the level of understanding of and proficiency in the topics covered prior to the assignment. Simulation Assignment One Matlab-Simulink or PSIM based drive system simulation assignment will be allocated to one Assignment Group of three students. Students will be expected to form their preferred groups by week 8. The purpose of these assignments will be to give students a taste of drive system simulation using suitable platforms and predict the steady-state and dynamic behaviour of a specified drive system. More than one group may have the same assignment. Course Assessment ELEC4613 Course Outline 4 F. Rahman

5 The distribution of assessment marks for the course is indicated below. Laboratory, including one report on an experiment to be advised. 20 % Report due in week 12 Mid-Session Test in week 7 10 % Assignment (using PSIM or Matlab/Simulink; 10 % Assignment due in week 13 Final examination 60 % Total 100 % Text Books and References 1. Electric Drive Systems comprehensive lecture notes from lecturer (F. Rahman) in PDF format will be available via Moodle for this course (ELEC4613). The following books may be consulted for further reading: Reference books: 2. Control of Electric Machine Drive Systems - Seung-Ki Sul, IEEE Press and John Wiley, Advanced Electrical Drives: Analysis, Modelling and Control R. De Doncker, D. Pulle and A. Veltman, Springer, ELEC4613 Course Outline 5 F. Rahman

Synchronous Motor Drives

UNIT V SYNCHRONOUS MOTOR DRIVES 5.1 Introduction Synchronous motor is an AC motor which rotates at synchronous speed at all loads. Construction of the stator of synchronous motor is similar to the stator