Comparative Evaluation of SiC based Two-Level Inverter With Passive EMI Filter Against Dual Two-Level Inverter Under PWM Schemes

Abstract

The two-level (TL) inverter employs a passive EMI filter to mitigate conducted common-mode (CM) electromagnetic interference (EMI) issues such as CM current and shaft voltage. Whereas the topology of dual two-level (DTL) inverter is emerged with the provision of dedicated pulse width modulation (PWM) scheme to eliminate the CM voltage and thereby considers the reduction of CM emissions in the system. However, the effect of CM voltage elimination on the attenuation performance of high frequency CM noise (up to 30 MHz) and shaft voltage in DTL inverter fed induction motor is not clearly stated in literature. Thus, this paper presents the theoretical and experimental discussion on comparative evaluation between TL inverter system with passive EMI filter and the DTL inverter under PWM schemes such as CM voltage elimination (CMVE) PWM and remote state PWM (RSPWM) scheme. The comparative evaluation is carried out in terms of attenuation of conducted CM emissions in relevance to the component requirement for both the systems. The experimental verification of the reported work is carried out for a 3-$\phi$, 1.1 kW IM driven in star configuration for TL inverter and open-end winding configuration for DTL inverter.