Permanent Magnet (PM) Synchronous and Brushless DC Motor Drives are natural candidates for high performance applications. With high volume applications in small processing drives, hand tools, automotive drives, home appliance drives such as HVAC, refrigerator, freezer, washer and dryer, the demand for engineers with a theoretical understanding of the PM synchronous and brushless drives is growing.

Interests in all electric vehicles (EV), hybrid EVs and corresponding interest in all electric and hybrid aircraft actuation offer exciting opportunities. The demand is increasing for more design, testing and application engineers to engineer these products. The demand for research and development engineers is also increasing from ways to realize position sensor and sensorless based drives, develop and design parameter insensitive controllers, all the way to providing auto-tuning with the process/load and with artificial intelligence.

Further, the end users of variable speed drives need to be knowledgeable about the latest developments in this field, its current status and its future direction to enable them to plan new capital investments wisely and to have the latest technology incorporated for their modernization of the plants.

This course is intended to address these requirements for engineers specializing in the motor drives (including electric motors, power electronics for these motors, and controllers) technology and end users in many aspects of this technology. A state-of-art coverage of the subject matter based on research publications is developed in this short-term course. 

Course is $1695 per participant.

  • A brief introduction to the permanent magnets, their characteristics, construction of the PM machines with their classification of the PM AC machines into PM Synchronous Machine (PMSM) and PM Brushless DC machine (PMBDCM).
  • The salient differences between the PMSM and PMBDCM are developed.The understanding of the control requires the dynamic model of the machines and they are derived from the fundamentals.
  • The vector control of the PMSM is derived and its implementation is discussed.
  • The need for flux weakening and the basic principle of flux weakening is developed systematically.
  • Various strategies for the control of PMSM with constant mutual flux linkages, unity power factor, maximum torque per unit current, constant torque angle control and constant loss are derived and their implementations are discussed.
  • Flux weakening control strategies are derived and their implementations in detail are given.
  • The current and speed controllers are analytically derived and verified with extensive dynamic simulations.
  • Rotor position sensor-less control is an important aspect of the emerging drive system and many algorithms for its implementation are presented.
  • The parameter sensitivity of the PMSM drives is studied and compensation methods are presented.  
  • The performance of the integrated drive system is presented.
  • Some MATLAB based software development will be referred to the course instructor’s book.

Similarly, for the PMDCM drives, the dynamic modeling, control strategies,  dynamic performance of the system, sources of  torque pulsations and their minimization,  torque smoothing algorithms, rotor position sensorless algorithms and their implementations, parameter sensitivity of the drive system and the sensor controllers, high speed operation and its limitations, and new converter topologies for high volume applications are presented.  MATLAB based code development for analysis of the PMBDCM drive system will be referred.

Photo of R. Krishnan, Ph.D.

Dr. Krishnan Ramu (writes under the name of R. Krishnan):  Professor Emeritus of electrical and computer engineering at Virginia Polytechnic Institute and State University. His research interests are in electric motor drives, electric machines, power electronics.

Books: (a) Author of: (i)  Electric Motor Drives (also translated into  Chinese, Greek) , (ii) Switched Reluctance Motor Drives, (iii) Permanent Magnet Synchronous and Brushless DC Motor Drives (translated into Chinese also). (b) coauthored one book (iv) Control in Power Electronics.

Publications: 170+ technical papers. Patents: 30 patents (27 US and 3 Japanese) and  6+ pending.

Awards:  (i) IEEE Industrial Electronics Society’s Dr. Eugene-Mittelmann Achievement Award for outstanding technical contributions to the field of industrial electronics, (ii) Anthony Hornfeck award for outstanding service to IEEE IE Society, (iii) IEEE Fellowship for contributions to ac and switched reluctance motor drives, (iv) Archer award for IP contributions from Regal Beloit Corp., (v) IEEE Industrial Electronics Distinguished Lecturer, (vi) Best book award from Ministry of Education and Sport, Poland, in 2003 for my coauthored book, Control in Power Electronics, (vii) six Best Paper Prize Awards from the IEEE Industry Applications Society, (viii) First Prize Paper Award from the IEEE Transactions on Industry Applications, (ix) Best Paper Award from the IEEE Industrial Electronics Magazine in 2007, and (ix) Life membership of AdCom, IEEE IE Society.

Teaching Experience: (i) College of Engineering, Guindy, Anna University, 1972-79, (ii) Concordia University, Canada 1979-81 and (iii) Virginia Tech 1985 – present.

Short courses: Delivered and organized a large number of short courses to industry in Electric motor drives, Power electronics, PM synchronous motor drives, Induction motor drives and Switched reluctance motor drives (all in USA, France, Italy, France, Greece, Korea, Portugal, and Denmark).

Specific Contributions in PMSM and PMBDCM Drives: He made original contributions in PM synchronous motor (PMSM) and PM brushless dc motor (PMBDCM) drives in their modeling, simulation, analysis and design. He led the development of the computer aided analysis tools for PMSM and PMBDCM drives way back in 1989. His original work covers design of axial field and radial field machines, control strategies, flux weakening controller, rotor position sensor-less starting of PMBDCM drive, control algorithm for rotor position sensor-less operation of PMBDCM drives using other than induced emf signals, parameter sensitivity and adaptive parameter compensation techniques, and many low cost power converter topologies for PMBDCM drives for high volume applications.

Consulting: Served as a consultant to more than 18 companies in USA.

Industrial Experience: Served in two US companies full time: (i) Principal engineer in Gould Inc, Rolling Meadows, Ill (‘82-‘85), and (ii) Business Leader and CTO of Ramu Inc., Regal Beloit America, Blacksburg, VA (’11-‘14).

Founder of two motor drives companies: (i) Panaphase Technologies which was acquired by Delta-Gee in 2007, and (ii) Ramu Inc., which was acquired by Regal Beloit Corporation in 2011 and also served as founding CEO and CTO for them. He has the distinct honor to be the only faculty in his area of research in the world to have started, operated and sold two successful companies in motor drives.

Current interests: (i) Writing books on motor drives, power electronics and control and he is writing an advanced control book on PMSM motor drives at present, (ii) Starting companies in the same areas and making them successful, and (iii) Inventions in PM and SR motors and power converters for them and their controls.