Abstract

The increased use in industry of sensitive power electronics-based equipment resulted in concerns about power quality in distribution systems. This has led to the proposal of more stringent requirements regarding power quality, in terms of current harmonics, as reflected in standards such as IEEE-519, and in terms of voltage faults. By exploiting recent advances made in power electronics and digital control circuits, this thesis develops new power conditioning solutions based on the PWM voltage source converter, with emphasis on their dynamic response. The proposed compensators include four-switch and six-switch based series and shunt configurations. The proposed control strategies implement state-space feedback control of the series compensator, direct power control of the shunt compensator and unified deadbeat control of the combined series-parallel compensator. These control algorithms present a number of advantages such as dealing with time varying control references in series compensation, integrating multiple control variables into one control loop in shunt compensation, and unified control of the combination of series-parallel converters. The improvements cover the global control functions as well as direct converter control and PWM functions. Simulation and experimental results from laboratory prototypes confirm the theoretical considerations.