Discretized Discontinuous Modulation Strategy for Cascaded H-Bridge StatCom

Identifier:  imarina:9282018

Handle: https://hdl.handle.net/20.500.11797/imarina9282018

Authors:  Liu, QX; Rodriguez, E; Farivar, GG; Pou, J; Leyva, R; Townsend, CD

Abstract:
This paper proposes a discontinuous modulation (DM) scheme for cascaded H-bridge (CHB) static compensators (StatComs) with star configuration. The proposed DM scheme guarantees zero steady-state active power in each converter phase-arm, even in the presence of severe grid imbalance conditions, thus remaining decoupled from the inter-phase capacitor voltage balancing controller. Moreover, the proposed DM scheme exploits the possibility of clamping to the zero-voltage level, thus providing a more flexible discontinuous operation than conventional DM methods. This involves lower zero-sequence-voltage injection requirements and lower switching losses. The proposed modulation scheme is experimentally corroborated and its performance under different grid voltage conditions is compared with traditional modulation schemes.