Voltage Stress in PWM Inverter-Fed Electrical Machines by Jiabin Wang and Antonio Griffo

By ITeN Editorial Board
10 November, 2021

Tuesday December 14, 2021 2:00 PM GMT (3:00 PM CET, 9:00 AM EST)

By Jiabin Wang and Antonio Griffo (University of Sheffield, UK)

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Power electronic converter-fed machines and drives are increasingly being used in electrification of transport, renewable energy generations and industrial automation. Converters operating in pulse width modulation (PWM) produce voltage pulses at a high frequency and high voltage slew rate (dv/dt) which can result in excessive voltage at the machine terminal and non-uniform voltage distribution within the windings. These voltage transients are expected to significantly reduce the lifetime of the insulation of the connected machine/generator due to increased voltage overshoot, increased voltage across turns, phases and phase-to-ground, and higher frequencies. These will be exacerbated by the increased use of wide band-gap devices with fast-fronted voltage transients with dv/dt in excess of 10-30kV/µs. In this talk, the effects of impulse and high frequency PWM voltages produced by fast-switching power electronic converters on voltage distributions in machine winding and insulation systems are analysed and characterised. Both high frequency oscillation modes due to the interaction of inverter, cables and machines, as well as a low frequency oscillation mode associated with the common mode impedance of machines, will be presented and its implication on inverter-driven operation discussed. Lifetime test results under partial discharges caused by high voltage slew rate will also be highlighted.

Presenters’ bio:

Professor Jiabin Wang graduated with a BEng in 1982 and MSc in 1996 from Jiangsu University in China, and a PhD in 1996 from the University of East London, UK, respectively, in electrical engineering. He is a professor in electrical engineering at the University of Sheffield. His expertise encompasses novel rotary and linear electrical machines and drives, advanced control techniques for electrical drives, electrical power-trains and ‘more-electric’ technologies for electric and hybrid vehicles, and aircraft. Currently, his research focuses on high integrity, fault tolerant and high efficiency electric drives and associated condition monitoring techniques for applications in aerospace, automotive and renewable energy systems. He has coordinated a large number of national and international projects such as the recent EPSRC funded project, on “Insulation degradation and lifetime of inverter-fed machines with fast switching (high dv/dt) converters”. He is a fellow of the IET and a senior member of the IEEE.

Dr Antonio Griffo received the M.Sc. degree in electronic engineering and the Ph.D. degree in electrical engineering from the University of Napoli “Federico II,” Naples, Italy, in 2003 and 2007, respectively. From 2007 to 2013, he was a Research Associate with the University of Sheffield, Sheffield, U.K., and the University of Bristol, Bristol, U.K. He is currently a Senior Lecturer with the Department of Electronic and Electrical Engineering, University of Sheffield. His research interests include modelling, control, and condition monitoring of electric power systems, power electronics converters, and electrical motor drives for renewable energy, automotive, and aerospace applications. He has participated in and coordinated a large number of projects on the design, control and condition monitoring of power electronics and motor drives systems for renewables, automotive and aerospace applications. He is Associate Editor of IEEE Transactions on Industrial Electronics.