A Nearest Level Control Scheme for Reduced Switch Count Cascaded Half-Bridge Based Multilevel DC Link Inverter Topology

Abstract

In this paper, a Nearest Level Control (NLC) scheme for Reduced Switch Count (RSC) cascaded half-bridge based Multilevel DC-Link (MLDCL)inverter topology with three different source configurations (1:1:1:1, 1:2:3:4 and 1:2:4:8) have been explained clearly. For generating particular level in the inverter output, NLC technique has been utilized. The NLC technique is generally a low switching frequency technique thereby switching losses are greatly reduces and it is suitable for any kind of inverter topology. The MLDCL topology consists of 8 unidirectional switches in the level generator side, 4 unidirectional switches in the polarity generator side and 4 dc sources. For generating P-level output, only P+3 switches are required then the requirement of gate driver circuits, protection circuits have been reduced. Basically, NLC technique is more suitable for higher level inverter topologies and provides best harmonic performance as compared with conventional Pulse Width Modulation (PWM) techniques. The operation and feasibility of the topology with control scheme have been validated through the MATLAB/Simulink platform.