THE USE OF DECOUPLED CONVERTERS TO OPTIMIZE THE POWER ELECTRONICS OF SHUNT AND SERIES AC SYSTEM CONTROLLERS

This paper presents a decoupled converter approach for solid-state com pensation of ac power systems. The scheme employs a multi-step inverte r for control of fundamental frequency components and PWM inverters fo r harmonic compensation. The inverters are arranged in such a manner t hat the high-frequency harmonic compensation module uses inverters of low power rating, while the slow-switching fundamental frequency compe nsation module supports most of the stresses. This decoupled approach is expected to result in a significant reduction in cost and losses as sociated with active compensators for high-power applications. The bas ic principle of operation, circuit structures and control strategy for shunt and series compensation based on the decoupled approach are des cribed. Computer simulation and experimental results are presented to demonstrate the performance of the proposed system.