A new buck/ boost bipolar quasi Z source NPC inverter topology for renewable energy resources

Abstract

This paper proposes a 3-Phase 3-Level Bipolar quasi-Z-Source Neutral-Point-Clamped-Inverter (BP-qZS-NPCI). It has buck/boost capability to interface renewable energy resources (RER) with AC load under input DC voltage variation. The symmetrical switching modulation technique is employed using Lower-Shoot-Through (LST) state and Upper-Shoot-Through (UST) state in the proposed 3-Level inverter topology. A comparison of 2-Level unipolar qZSI with the proposed 3-Level BP-qZSNPCI is analyzed by performing simulations of each in Simulink/Matlab. The constant boost control(CBC) modulation technique is used to develop the switching pattern for IGBT switches of the proposed inverter. To verify theoretical and simulated proposals, an experimental inverter (500W) developed to illustrate the merits of the proposed inverter topology over 2-Level conventional quasi z-source inverter (qZSI). A satisfactory agreement was found between simulation results and the experimental data.