A Simplified Space-Vector PWM Scheme for N-Level NPC Inverter Based on Two-Level Space-Vector PWM

Abstract

This paper proposes a general dwell-time equations for N-level inverter that are derived without the complex calculation. Contrary to the conventional method which has two dwell-time equations due to types, the proposed dwell-time equation is defined as one equation without the separated types. This method proceeds following step. After the voltage reference in abc-coordinate are transformed to alpha and bata coordinate, the dwell-times of each vector are derived from the equation of time balance and voltage-time characteristic equation. Next, the space-vector diagram of N-level inverter is simplified to the space-vector diagram of two level inverter by moving the alpha-axis component and bata -axis component respectively. Finally, only one general equation is derived. Availability of the proposed general equation is verified by the simulation results