A Study on Performance and Stability of Current Control Systems by Using Multi-Level Inverters

In motion control systems, detailed characteristics of power converters are usually not considered. Practically, voltage ripple, harmonics, and electromagnetic interferences (EMI) generated in widely used 2-level inverters become concerns to realize a high-performance control. Compared with 2-level inverters, multi-level (ML) inverters essentially reduce these problems. Furthermore, the equivalent carrier frequency of N-Ievel ML inverters is expected to be N-l times higher than that of the 2-level inverters in case that a carrier phase-shifted modulation is utilized. This paper focuses on the equivalent carrier frequency and studies the performance and stability of current control systems by using ML inverters.