Generalized Carrier Based Technique for Eliminating CMV in 3-Phase n-level NPC Inverter

Abstract

A carrier based technique is presented in this work for eliminating Common Mode Voltage (CMV) in a n-level $3\Phi$ Neutral Point Clamped (NPC) multi-level inverter, where number of level ‘n’ is odd. The switching state of n-level $3\Phi$ , NPC inverter with zero CMV is determined as difference between switching states of two phases of a p-level inverter where $\mathbf{p}=(\mathbf{n}+1)/2$ . The proposed Carrier Based Pulse Width Modulation (CBPWM) strategy applied is simpler than Space Vector Modulation (SVM) technique. Hence, the algorithm can be implemented in real time with less hardware resource. The validity of the carrier based scheme for elimination of CMV is evaluated for a 5-level 3Φ, NPC inverter through a simulation study in Matlab/ Simulink.