Novel four-bridge PWM static VAr compensator

A novel four-bridge PWM static VAr compensator is presented. Theoretical analysis shows that the harmonic pairs of [(2k + l)f, ancl [(4k + 2)f, +A] generated in each bridge are effectively eliminated through appropriate phase shift control. To satisfy the same 5% total harmonic distortion requirement, this new compensator can work at 200Hz, which is much lower than the previously reported 1.9kHz of a single-bridge PWM static VAr compensator The efficiency is increased and reliability is enhanced. The fairly low switching frequency and multiplebridge structure facilitate its use in a high-power VAr compensator since GTO can be employed as the power switch. Theoretical analysis was verified through simulations and experimental results.