A New Single-Phase Five-Level Neutral Point Clamped Cascaded Multilevel Inverter for Minimization of Leakage Current in PV Systems

This paper presents a new single-phase five-level neutral point clamped (NPC) cascaded multilevel inverter (CMLI) for the minimization of leakage current in PV systems. Using the given PWM technique, the proposed five-level NPC CMLI topology reduces the transitions in the terminal and common mode voltages. The transitions in the terminal and common mode voltage are reduced by using DC side neutral point clamping technique. Due to the reduction of transitions in terminal voltage, the magnitude of leakage current flowing through the parasitic capacitance of PV panel reduces. Apart from the leakage current, the common mode current also reduces using the proposed CMLI. Because of reduction in the common mode current, the size of EMI filter and choke required at the output of CMLI reduces. The proposed fivelevel NPC CMLI is also generalized for the higher levels in the inverter output voltage. The analysis of terminal and common mode voltages for the proposed five-level NPC CMLI using the switching function concept is presented in the paper. The simulation results of the proposed five-level NPC CMLI are also presented to justify the concept.