Multilevel inverters (MLIs) have gained popularity due to the emerging medium and high-power drive applications such as heavy-duty electric vehicles, electric aircraft, and urban air mobility. A neutral-point-clamped, cascade H-Bridge and flying capacitors are the potential candidates for these applications, but these conventional MLIs have either stacked or floating capacitors causing voltage unbalancing and drifting issues in variable-speed operation. In this paper, a new neutral-point-less (NPL) MLI topology is proposed, which requires neither stacked nor floating capacitors, topologically addressing the voltage balancing and drifting issues. The new NPL MLI topology, namely X-type inverter, reduces the required capacitance and volume of the dc-link capacitor by over 75% compared to that of the conventional MLI topologies. In addition, the X-type inverter produces two equal and opposite common-mode (CM) voltage waveforms, which cancel out the capacitive leakage current for the minimum CM electromagnetic interference (CM EMI) noise. This paper introduces the new NPL MLI topology and the underlying principle of multilevel operation without stacked or floating capacitors. The simulation results verify the NPL multilevel operation with a single dc-link capacitor and over 50 dBuV CM EMI noise reduction compared to that of the conventional two-level inverter.
Operating Principle of Neutral-Point-Less (NPL) Multilevel Inverter Topology: X-type Inverter
2022-06-15
1782673 byte
Conference paper
Electronic Resource
English
Modified Topology and Modulation Technique for Z-Source Neutral-Point Clamped Inverter
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