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      https://www.ias.ac.in/article/fulltext/sadh/042/06/0827-0839

    • Keywords

       

      Current control; current stress; diode-clamped inverter; full-bridge inverter; half-bridge inverter; multi-level inverter; proportional-resonant controller; sinusoidal modulation; vector control; voltage ripple

    • Abstract

       

      The sizing of the DC-link capacitor in a three-level inverter is based on the RMS current flowing through it. This paper analyses the DC-link capacitor RMS current in a neutral-point clamped (NPC) inverter and expresses the same as a function of modulation index, line-side current amplitude and power factor. Analytical closed-form expressions are derived for the capacitor RMS current for single-phase half-bridge,single-phase full-bridge and three-phase three-leg topologies of a three-level inverter. The worst-case capacitor current stress is determined for each topology based on the analytical expressions. Further, analytical expressions are derived for the RMS values of low-frequency and high-frequency capacitor currents. These expressions are then used to estimate voltage ripple across the DC capacitor for sinusoidally modulated three-phase NPC inverter. The analytical expressions for the RMS current and voltage ripple are validated experimentally over a wide range of operating points.

    • Author Affiliations

       

      K S GOPALAKRISHNAN1 SANTOSH JANAKIRAMAN1 SOUMITRA DAS2 G NARAYANAN1

      1. Department of Electrical Engineering, Indian Institute of Science, Bangalore 560012, India
      2. Department of Electrical and Electronics Engineering, National Institute of Technology Goa, Farmagudi, Ponda 403401, India
    • Dates

       
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