An Improvement of Power Quality Using 4-Leg (VSC) Based DSTATCOM
Excessive neutral current, harmonics and reactive power burden and unbalance are usually caused through Large number of single-phase linear and nonlinear loads which may be supplied from three phase ac mains with neutral conductor. A four wire DSTATCOM (distribution static compensator) is used for neutral current compensation along with reactive power compensation, harmonics elimination and load balancing. A four - leg voltage–source converter (VSC) with a dc capacitor is used as a four wire DSTATCOM. The proposed control approach is based on synchronous reference frame (SRF) theory. The switching signals for the voltage–source converter (VSC) of the DSTATCOM are derived from the estimated reference supply currents. The load balancing, harmonics elimination and the neutral current compensation are demonstrated along with unity power factor (UPF) and zero voltage regulation (ZVR) modes of operation. The DSTATCOM is able to maintain the selfsupported dc bus under various disturbances. MATLAB Simulink toolbox are used to execute the simulations.