A Novel Current Control Scheme for Three-Phase Three-Level Grid-Tied Neutral Point Clamped Inverter

In this paper, a simple and novel current control scheme for three-phase three-level grid-tied neutral point clamped (NPC) inverter is proposed. In this control scheme, conventional space vector modulation (SVM) is basically reflected with a new digital switching approach. In this approach, PI controller and phase-locked loop (PLL) are not used unlike to that of conventional space vector modulation (SVM). Therefore, the computational burden on the processor reduces as compared with the conventional SVM technique and is simple to execute. The NPC inverter with proposed current control scheme can be applicable in wind energy conversion and photovoltaic system-related applications. Simulation studies are validated for the proposed current control scheme for three-phase three-level grid-tied NPC inverter with MATLAB/Simulink platform. By using the proposed control scheme, it is possible to get grid synchronization easily without using the phase-locked loop concept. This scheme also gives a good transient/dynamic response for injected grid current reference values.