Politechniki Łódzkiej
Plenary session
Plenary lecture „Energy Efficiency for High-Power Electrical Drives” will be given by professor Joachim Holtz
Methods for increasing the power rating and the efficiency of high-power drives are subject of the Keynote Address. The current rating of medium voltage semiconductor devices determines the motor currents, while the motor voltages are stepwise increased as the power level in increased. Connecting power devices in series creates losses in associated circuits for dynamic voltage balancing. Loss-less balancing of a pair of series connected devices is enabled by the three-level inverter topology. A side effect is reducing the harmonic current distortion which reduces resistive motor losses. The voltages are further increased by series connection per the 6respective phases of three-level inverter legs. Output power of several hundred megawatts is thus achieved. Carrier modulation requires switching frequencies around 1 kHz. Optimal modulation techniques permit operating below 200 Hz without increasing current distortion. The device switching losses are thus reduced. It increases the power rating of a given inverter by about 250% and the efficiency is 99% in 28-MW drive.
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Professor Joachim Holtz has extensively published, among others 12 invited papers in journals. He has earned 15 Prize Paper Awards. He is the coauthor of four books, and holds 32 patents. Professor Joachim Holtz is the recipient of the IEEE Industrial Electronics Society Dr. Eugene Mittelmann Achievement Award, the IEEE Industrial Applications Society Outstanding Achievement Award, the IEEE Power Electronics Society William E. Newell Field Award, the IEEE Third Millenium Medal, the Anthony J. Hornfeck Service Award, and the IEEE Lamme Gold Medal. He is a Life Fellow of the IEEE. Professor Joachim Holtz is Past Editor-in-Chief of the IEEE Transactions on Industrial Electronics, Distinguished Lecturer of the IEEE Industrial Applications Society and IEEE Industrial Electronics Society. |
Professor Joachim Holtz graduated in 1967 and received the Ph.D. degree in 1969 from the Technical University Braunschweig, Germany. In 1969 he became Associate Professor and, in 1971, Full Professor and Head of the Control Engineering Laboratory, Indian Institute of Technology in Madras, India. He joined the Siemens Research Laboratories in Erlangen, Germany, in 1972. From 1976 to 1998, he was Professor and Head of the Electrical Machines and Drives Laboratory, Wuppertal University, Germany. He is presently Professor Emeritus and a Consultant.