Statcom based on space vector pulse density modulated inverter

A Pulse density modulation scheme is proposed for generating firing pulses to the voltage source inverter of a STATCOM. A three phase two level inverter is used as voltage source inverter. The capacitor voltage of inverter is maintained at a constant value. In pulse density modulation scheme all firing pulses have constant width but the number of pulses to the inverter switches varies. Space vector modulation technique is used for generating PDM firing pulses. PI controller is used for controlling STATCOM. Pulse density modulation scheme brings low interference and low noise thus improving the performance of STATCOM. Space vector modulation reduces harmonic distortions, minimizes switching stresses and gives accurate control for inverter voltage. A STATCOM of 3MVA is simulated with the proposed scheme and results are observed.