Plenary Lecture

Influence of Non-Ideal Input Supply Voltages on the Electromagnetic Torque of PWM VSI Fed Induction Motor Drive

Professor Jiri Klima
Dean of Faculty of Engineering
CZU in Prague, Czech Republic

Abstract: The DC-link voltage ripple in power inverters is composed of several sources such as:

a) The diode rectification of the AC-line voltage causes pulsation components
b) Unbalanced and sags in the ac power supply generates 100 or 120-Hz component
c) In some faulty conditions in the front-end rectifier the DC-link voltage may again contain pulsations

The closed-form mathematical model and analysis of the ripple components of the DC-link voltage of the three-phase voltage source inverter and its influence on an induction motor drive both in time and frequency domains are presented in this paper. The analytical expressions for the voltage and current space-vectors as a function of the DC-link voltage pulsation are derived for the space-vector PWM operation mode. From the current space vectors, the electromagnetic torque behavior is estimated again as a function of the DC-link voltage ripple. The proposed analytical method is based on the mixed p-z approach enabling presentation of the results in the closed-form. Experimental results are included in order to verify the derived expressions.

Brief Biography of the Speaker:
Jiri Klima, received his MSc and PhD degree in electrical engineering for Technical University in Prague in 1968 and 1978, respectively.
Since 1970 he has been in the Department of Electrical engineering and Automation, Technical Faculty of CZU in Prague. Since 2003 he is a dean of the Technical Faculty.
He is author of more than 200 technical papers including IEE and IEEE Journals. He served as a chairman of 4 Electrical Engineering Conferences
His main field of interest is the mathematical modelling of electric circuits with the discrete components, electrical drives and power electronics. He is associate editor of the Journal Transaction on Power Systems (WSEAS).In 2004-2008 he has been listed in Marquis “Who is who in the world”.