Integrated three-level NPC based DSTATCOM topology using MISCT control algorithm for load compensation with non-stiff source

In this paper, a three-level neutral-point-clamped (NPC) inverter based filter capacitor supported integrated distribution static compensator (DSTATCOM) topology is proposed for load compensation using modified control algorithm. A three-phase four wire low voltage distribution system is taken into consideration with non-stiff source. The suggested topology is realized using three-level NPC voltage source inverter (VSI) with series capacitor to reduce dc link voltage and shunt capacitor to eliminate the high frequency switching components. In addition, a positive sequence component extraction based modified instantaneous symmetrical component theory is also suggested for load compensation (MISCT) in non-stiff system. Various DSTATCOM configurations are analyzed based on the filter capacitor combinations using MISCT and compared with conventional instantaneous symmetrical component theory (CISCT) for DSTATCOM applications, using hysteresis pulse width modulation (PWM). The performance analysis carried through an extensive MATLAB simulation shows excellent improvement in load compensation with significantly lower total harmonic distortion (THD) and reduced switching components in the terminal voltage for integrated DSTATCOM structure with series and shunt filter capacitor using MISCT.