Performance Evaluation of Nine Level Modified CHB Multilevel Inverter for Various PWM Strategies

In this paper nine level Modified Cascaded H-Bridge Multilevel Inverter (CHB-MLI) is analyzed for the various multi-carrier Pulse Width Modulation strategies. For the same nine level inverter output this particular topology has reduced count of switches, on comparing with the conventional Cascaded H Bridge Multilevel Inverter. For a single phase, nine level inverter output this topology requires one H-bridge and a multi conversion cell. Four equal voltage sources with four controlled switches and four diodes comprise a multi conversion cell. Instead of sixteen controlled switches as in conventional method, this topology requires only eight switches to obtain nine level output. The reduction of switches lowers switching losses, cost and total harmonic distortions. Performance parameters have been analyzed for the nine level CHBMLI.