An analysis of neutral point potential control for a three-level NPC inverter

Abstract EN

This paper deals with the analysis of a control system for a three-phase three-level inverter with a Neutral-Point-Clamped topology.

This last is a good topology for high voltage, high power applications and low current waveform distortion.

However, it has an inherent problem of neutral point potential variation.

In this way, a Direct Torque Control (DTC) technique has been applied and the estimated value of the Neutral Point Potential (NPP) is used, which is calculated by motor currents.

This control strategy offers the possibility of selecting appropriate switching state through a switching table to achieve the control of NPP.

This study shows the effect of the stability problem of the DC voltages on the DTC performances.