Abstract
AbstractA voltage sag is a sudden reduction (between 10-90%) in the voltage magnitude, and lasting for 0.5 cycles to several seconds. Voltage sags have become one of the most important power quality issues in recent years. In the Hsin-Chu Science Based Industrial Park, where most high-tech facilities in Taiwan are located, voltage sags are the most frequent cause of disrupted operations and subsequently interrupt the manufacturing processes.In this thesis, two voltage sags ride-through techniques are developed. First, a control method with improved detection time is implemented for the Solid-State Transfer Switch for medium voltage level. The other technique is developed for Field Oriented adjustable speed drives. By decreasing the frequency of the inverter, the induction motor is forced into negative slip, and the motor’s rotational energy is recovered to maintain the DC Link voltage to avoid under voltage fault of the inverter.This thesis will provide a survey of related literature, and discuss the control function of the proposed techniques in detail. Simulation and laboratory test results are presented to validate the effectiveness of the proposed techniques.