Impact of PWM Schemes on the Common-Mode Voltage of Interleaved Three-Phase Two-Level Voltage Source Converters.

Interleaved three-phase voltage source converters (VSCs) are widely applied in industry. The circulating current issue has been the focus so far in literature. However, the common-mode voltage (CMV) generated from interleaved VSCs, which is also a key factor that influences the system's performance, has not yet been studied in detail. In this paper, the impact of pulsewidth modulation (PWM) strategies on the CMV of interleaved two-level VSCs is analyzed. The analysis is conducted based on the double Fourier integral theory and in a generalized way considering an arbitrary number of interleaved converters. Five PWM schemes are considered, including the interleaved sinusoidal PWM (ISPWM), the interleaved space vector modulation (ISVM), the interleaved discontinuous PWM (IDPWM), and the recently proposed interleaved carrier phase-shift PWM (ICPS PWM), and interleaved carrier phase-shift SVM (ICPS SVM). Both magnitude and harmonic content of CMV are examined for each method. The analysis reveals that with ISPWM, ISVM, ICPS PWM, and ICPS SVM, the CMV can be reduced. In contrast, interleaving has little impact on the CMV with IDPWM, which is always at VDC/2 due to high low-order harmonics, making it less attractive for drive applications using coupled architecture. For modular architecture, ICPS PWM and ICPS SVM are more desirable considering their low-ZSCC peak value. The study is verified through experimental results. [ABSTRACT FROM AUTHOR]