Research on Space Vector Overmodulation Technology of Two-Level PWM Converters

Abstract

In this paper, the characteristics of the voltage transfer ratio (VTR) and low-order harmonics of the major modern space vector overmodulation strategies for two-level PWM converters are discussed under different VTRs, and the complexity of the modulation algorithm is subsequently elaborated. First, the principles of these overmodulation strategies are summarized. After that, the accuracy and linearization of the VTR are obtained using the Fourier transform analysis, and the relationship between the main low harmonic components and the VTR is obtained in the same way. All the analysis results are verified through experiments. In addition, the merits and demerits of these overmodulation strategies and applications are revealed by comparing the simplicity of their modulation algorithm, digitization, and other characteristics. Finally, this paper reveals the essence of space vector overmodulation strategies. The results facilitate the design, performance prediction, and development of high-performance overmodulation strategies, as well as the transplantation of space vector overmodulation strategies into different converter topologies.

Keywords

• voltage transmission ratio (VTR)
• low-order harmonic components
• two-level PWM inverter
• space vector overmodulation