A new scheme for power factor correction and active filtering for six-pulse converters loads

Abstract

This paper presents a novel harmonic-free power factor correction (PFC) topology based on T-type active power filter (APF), which is dedicated for power factor improvement and harmonic filtering for six-pulse converter loads. The cascaded controller structure is adopted for the proposed system, namely, the inner current loop and outer voltage loop. The current-loop control scheme is based on a decoupled state-space equations of the T-type APF using separate proportional-integral (PI) controllers in d-axis and q-axis of the synchronous rotating reference frame (SRRF) synchronized with grid voltages, respectively. The fundamental components of load-side currents are feed forwarded in the current-loop using two groups of synchronous frame adaptive linear neural networks (ADALINEs) to ensure estimation accuracy and a fast dynamic response. A separate proportional-integral (PI) controller is adopted in the outer voltage loop for balancing the active power flow of the voltage source inverter (VSI) dc-side capacitor. The experimental results confirm well with the theoretical analysis.