Quasi-Resonant DC Link Control of 3-Dimensional Hysteresis Current PWM Technique in 3-Phase 4-Wired Power Quality Compensator

In this paper, quasi-resonant DC link (QRDCL) softswitching 3-dimensional hysteresis current control for power quality compensator is investigated. Power quality compensator here is the shunt active power filter in the 3-phase 4-wire system to compensate the imbalance, reactive power, harmonics and neutral current. The 3-dimensional hysteresis current PWM technique changes the system frame from a-b-c coordinate to alpha-beta-O coordinate for the purpose of controlling the neutral current individually in the 3-phase 4-wire system. And the quasi-resonant DC link soft-switching technique improves the performance of system with higher switching frequency and lower switching losses, etc. and enhances the PWM capability with inherent variable position and time interval of zero-voltage. The easy time sequence matching simplifies the system control and the results of simulation verified by the software PSCAD/EMTDC are found to be satisfactory to eliminate the switching losses without affecting the performance of power quality compensator