Self-Identification Strategy for an Inverter Nonlinearity Compensation of Three-Level Inverter

This article proposes a self-commissioning strategy for an inverter nonlinearity compensation of a three-level voltage source inverter (VSI), represented by neutral point clamped (NPC) and T-type NPC (TNPC). Inverter nonlinearity of three-level VSIs is relatively large since three-level inverters have more switching devices than the conventional two-level inverters. The inverter nonlinearity of a three-level inverter can be classified as the output voltage distortion and the pulse skipping. This article analyzes the output voltage distortion of three-level VSIs based on the physical structure. A self-commissioning strategy to identify and compensate for the output voltage distortion considering the pulse skipping of three-level VSIs is proposed in this article. The proposed method was verified through experiments using an industrial drive system. The experimental results proved that the proposed method could compensate for the inverter nonlinearity of three-level VSIs.