Showing papers on "PWM rectifier published in 1990"

A high switching frequency IGBT PWM rectifier/inverter system for AC motor drives operating from single phase supply

Abstract: A PWM (pulse width modulation) rectifier/inverter system using IGBTs (insulated-gate bipolar transistors), capable of switching at 20 kHz, is reported. The base drive circuit for the IGBT, incorporating short circuit protection, is presented. The inverter uses an Undeland snubber together with a simple energy recovery circuit, which ensures reliable and efficient operation even for 20 kHz switching. The front end for the system is a regenerative single-phase full-bridge IGBT inverter along with an AC reactor. The steady-state design considerations are explained, and control techniques for unity power factor operation and fast current control of the front end converter, in rotating as well as stationary reference frames, are discussed and compared. Results from computer simulations and experimental results for a 1.5 kW prototype system using GE type 6E20 IGBTs are presented. >

PWM rectifier with low DC voltage ripple for magnet supply

Abstract: Control techniques that optimize the behaviour of pulse-width modulation (PWM) rectifiers for magnet supplies are examined. Different control strategies, both with preprogrammed and variable switching patterns, are examined and compared in terms of optimization of the system performance. Optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta techniques are analyzed. The validity of the control methods was verified by simulation and experimental tests on a 60 kW prototype. It was observed that, in practice, digital PWM techniques are better suited for optimizing the AC converter performance, while delta modulation techniques give better results in terms of DC current and voltage distortion. >