Predictive Control of Seven Level Multi-level Inverter Based Single Phase Shunt Active Filter

Abstract

This paper describes a single-phase modified packed U-cell seven-level multilevel inverter (MPUC7) with finite control set model predictive control (FCS-MPC) for a single phase shunt active power filter application. The shunt active filter can directly inject the harmonic load current and compensate for the reactive power of the load and thus, make the grid current sinusoidal and in-phase with the grid voltage. The active filter improves the power factor and THD of current at point of common coupling (PCC). The MPUC7 is a six switch seven level inverter with only two dc-link capacitors. The mathematical model of shunt connected MPUC7 converter is explained for derivation of the next sample prediction required for FCS-MPC. The cost function for the constraint of tracking current and regulating the two dc-link voltage is mentioned. The filter reference currents are derived using direct control method. The single-phase active filter application is simulated in the Matlab/Simulink to validate the operation and robustness of the FCS-MPC current controller. Various non-linear load changes are simulated to verify the effect on dynamic operation.