Three-Dimensional Space Vector Modulation Strategy for Capacitor Balancing in Split Inductor Neutral-Point Clamped Multilevel Inverters

Abstract

Capacitor imbalance is one of the major drawbacks of a neutral-point clamped multilevel inverter (NPC-MLI). The capacitor imbalance rises due to the nonuniform switching, nonideal DC link capacitors, improper commutation, and various asymmetrical phase currents in switching states. The imbalance can be minimized by using proper switching using a redundancy switching method and avoiding the usage of medium vectors. The computational cost of this system is to be decided by the level of the inverter system. This paper presents a comprehensive three-dimensional space vector modulation (3D-SVM) strategy to eliminate the imbalance in the DC link capacitor voltage, which is across the applied input DC source. The technique is easy to implement without using any trigonometric functions, lookup tables, or angle determinations. This proposed scheme has been verified using MATLAB Simulink and authenticated using field-programmable gate array (FPGA) controller.