NOVEL 4-BRIDGE PWM STATIC VAR COMPENSATOR

A novel four-bridge PWM static VAr compensator is presented. Theoretic al analysis shows that the harmonic pairs of [(2k + 1)f(s) +/- f] and [(4k + 2)f(s) +/- f)] generated in each bridge are effectively elimina ted through appropriate phase shift control. To satisfy the same 5% to tal harmonic distortion requirement, this new compensator can work at 200Hz, which is much lower than the previously reported 1.9kHz of a si ngle-bridge PWM static VAr compensator. The efficiency is increased an d reliability is enhanced. The fairly low switching frequency and mult iple-bridge structure facilitate its use in a high-power VAr compensat or since GTO can be employed as the power switch. Theoretical analysis was verified through simulations and experimental results.