Introduction to Electric Machines and Drives

Gain a comprehensive introduction to electric machines and drives, covering core principles from AC system fundamentals and machine dynamics to modern inverter and drive control techniques. Designed for both newcomers and seasoned professionals seeking a refresher, the course leverages industry expert insights and practical design examples to boost productivity, efficiency, and overall system performance. This program is ideal for professionals aiming to enhance their understanding and application of electric drive technologies.

• Engineers and technicians working in appliance drives, cranes and elevators, precision motion control, and renewable energy.
• Professionals involved in electric/hybrid-electric vehicles, autonomous vehicle control, aerospace, marine, and military vehicles.
• Individuals seeking a refresher or new knowledge in the field of electrical rotating machines and drives.

This course is part of the Electrified Systems Certificate series. Course may be taken individually as well.

Introduction

Review: AC Systems and Three-Phase Circuits

• AC voltages and currents
• Effective or RMS values
• Complex numbers and phasor concepts
• Why three-phase?
• Harmonics
• Per-unit system

Review: Electromagnetics and Energy Conversion

• Magnetic fields, flux, and force
• Faraday’s Law of Induction
• Ferromagnetic materials
• Inductors and transformers
• The DC machine

Basics of AC Machines

• Elementary AC machines: air-gap MMF, flux, voltage waveforms
• Distributed stator windings
• Elementary rotor-stator coupling
• Three-phase operation

Induction Motors: Steady State

• Induction machine types: wound rotor, “squirrel cage” rotor
• Circuit models
• Concept of slip
• Torque-speed curves

Synchronous Machines: Steady State

• Synchronous machine types: wound rotor, permanent magnet
• Circuit models and vector diagrams
• Capability curves

Converter Power Electronics: Basic Theory, Devices

• Review of circuit fundamentals
• Basic converters
• Conversion stages
• Device characteristics and capabilities

AC Inverter Basics: VSI, CSI, Modulation

• Basic inverter system
• Voltage source inverter (VSI)
• Current source inverter (CSI)
• Modulation techniques
• Pulse width modulation (PWM)
• Practical considerations

Adjustable Speed Drives: Basics

• Basic adjustable speed drive systems
• Review: DC machine speed control
• Varying voltage
• Varying frequency
• Motor and drive selection

Adjustable Speed Drives: Volts/Hz Control

• Concepts of constant flux and torque
• Operation at constant torque or power
• Low speed operation
• Basic Volts-per-Hertz system
• Drive limitations

Adjustable Torque Drives: Basics

• Ideal adjustable torque systems
• Review: DC machine torque control
• Key elements of torque control
• Synchronous machine torque
• Induction machine torque-slip control

Induction Motor Field Orientation

• Review machine forces: Lorentz and reluctance
• Rotating vectors: stator and rotor currents
• Lorentz force control = vector control
• AC current regulation
• IM slip and torque production

Application-Specific Selection of Machine-and-Drive Systems

• Load types and characteristics
• Specific drives to suit application
• Practical issues of machine and drive selection
• PM versus IM
• Installation considerations

Application of Wide Bandgap Devices to Power Electronics

• Review of Silicon Carbide (SiC) and Gallium Nitride (GaN) devices
• DC-DC converter example using SiC
• 2-level VSI using SiC and GaN inverters

High-Speed Electric Machines

• Review of high speed electric machines
• Sizing equation and definition of tip speed
• Pros and cons of each machine for high speed
• High-speed machine design considerations

Thomas Jahns

Dr. Thomas M. Jahns received his bachelors, masters, and doctoral degrees from MIT, all in electrical engineering.

Dr. Jahns joined the faculty of the University of Wisconsin-Madison in 1998 in the Department of Electrical and Computer Engineering.  He served for 14 years as a Co-Director of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC), a world-renowned university/industry consortium in the electrical power engineering field.  Since 2021, he is the Grainger Emeritus Professor of Power Electronics and Electrical Machines.

Prior to coming to UW-Madison, Dr. Jahns worked at GE Corporate Research and Development (now GE Global Research) in Niskayuna, NY, for 15 years, where he pursued new power electronics and motor drive technology in a variety of research and management positions. His current research interests at UW-Madison include integrated motor drives and electrified propulsion for both land vehicles and aircraft.

Dr. Jahns is a Fellow of IEEE.  He received the 2005 IEEE Nikola Tesla Technical Field Award “for pioneering contributions to the design and application of AC permanent magnet machines”.  Dr. Jahns is a Past President of the IEEE Power Electronics Society.  He was elected to the US National Academy of Engineering in 2015 and received the IEEE Medal in Power Engineering in 2022.

Michael Ryan

Michael Ryan received his B.S. in Electrical Engineering from the University of Connecticut, Storrs,1988, M.E. degree in Electrical Engineering from Rensselaer Polytechnic Institute, Troy, NY, 1992, and Ph.D. in Electrical Engineering from the University of Wisconsin-Madison, 1997. At UW-Madison, Ryan worked in the WEMPEC labs on projects including dc–dc converters, variable-speed generation systems, and UPS inverter control.

Ryan is President of Ryan Consulting, involved in the application of Power Electronics and Controls, particularly for Alternative Energy systems. He has held prior positions at Capstone Turbine, General Electric Corporate Research and Development and Defense Systems divisions, Automated Dynamics, Otis Elevator, and Hamilton Standard.

Renato Amorin Torres

Renato Amorim Torres received the B.Sc. degree in electrical engineering from the Federal University of Minas Gerais, Belo Horizonte, Brazil, in 2016, and the M.S. and Ph.D. degrees in electrical engineering from the University of Wisconsin–Madison, Madison, WI, USA, in 2020 and 2022, respectively. During his M.S. and Ph.D. studies, he was a Research Assistant with the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC). Since completing his Ph.D., he has been working as a Researcher in Electric Machines and Drive Systems at General Motors Research and Development. His research interests includes power electronics and electric machines with focus areas on machine controls, wide-bandgap power devices, power electronics integration and EMI.

Ayman El-Refaie

Ayman M. EL-Refaie received the M.S. and Ph.D. degrees in electrical engineering from the University of Wisconsin– Madison in 2002 and 2005, respectively. Since 2005, he has been with the Electrical Machines and Drives Laboratory, General Electric Global Research Center, NY, USA as a Principal Engineer and Project Leader. He is the author of more than 50 journal, and 85 conference publications with several others pending. He holds 45 issued U.S. patents with several others pending. His research interests include electrical machines and drives. Since January 2017 he became the Thomas and Suzanne Werner Endowed Chair in Secure and Sustainable Energy at Marquette University. He is a Fellow of the IEEE

Erick Oberstar

Dr. Oberstar is a Program Director with InterPro and has over 28 years of engineering and entrepreneurial experiences. At InterPro he manages programs for and teaches in the areas of AI/ML, Electrification, and Mechatronics. He has deep experience in embedded real time control systems, signal and image processing, robotics, automation, medical devices. He managed the UW-Madison Mechatronics Laboratory for 22 years where he taught courses in mechatronics, manufacturing automation, automatic controls, and discrete time controls.

He has previous technical roles as a Scientist in the dept. of Medical Physics at UW, consultant for St. Jude Medical, and electrical engineer for Orbital Technologies Corporation, and Automation Components. In addition, he has numerous entrepreneurial experiences working on blood flow quantification, night vision, bacterial detection, robotics, automation, and general product development. 

Dr. Oberstar has a Ph.D in Biomedical Engr., and MS in Electrical and Computer Engr. (WEMPEC) from U.W. – Madison, and a BS Electrical Engr. from U.W. – Platteville. He has over 30 publications with over 400 citations & 3 patents. Dr. Oberstar is a WI Professional Engineer, Harvey Spangler Award for Technology Enhanced Education winner & judge, as well as a SPIE member & senior member of IEEE

Caleb Secrest

Caleb W. Secrest received a Ph.D. degree in mechanical engineering from the University of Wisconsin - Madison in 2015. From 2011 to 2015, he was a Graduate Researcher at WEMPEC under Prof. R.D. Lorenz performing research on improving motor drive precision in order to utilize it as an embedded application specific sensor. From 2015 to 2019, he was a Sr. Motor Control Engineer at General Motors with focus on automotive traction application electric machines and power electronics (EMPE) control.  Currently, he is a Sr. Manager at BorgWarner Inc. where he leads a global team on the development and integration of EMPE systems and software for automotive traction applications.

James Swanke

James Swanke is an electrical machine designer with an extensive academic and professional background in electrical engineering. Graduating from the University of Wisconsin-Madison with a B.S. in 2014, a M.S. in 2019, and a PhD in 2023, James has developed a deep expertise in high-performance electrical machines. Prior to pursuing advanced degrees, he gained valuable experience working for Siemens specializing in the electromagnetic design of induction machines. During graduate studies, his research focused on the advancement of high-power density and fault-tolerant electrical machines for aerospace propulsion applications. Currently, James applies this extensive knowledge at H3X Technologies, where he continues to work on the development of cutting-edge permanent magnet machines.