A Modified SVPWM Algorithm Providing Solution to Capacitor Balancing Problem in Diode-Clamped MLI in the Entire Modulation Region

Bharatiraja Chokkalingam, Jeevananthan Seenithangam, Vijayalakshmi Subramanian, and Subhransu Sekhar Dash


Neutral point fluctuation (npf), Neutral-point Diode-Clamped Multi LevelInverter (NPC-MLI) , Space Vector PWM (SVPWM), MATLAB-Simulation


This paper presents a modified SVPWM algorithm to control DC-link imbalances in the three-level NPC-MLI. The proposed scheme is a result of the blend of the techniques: Nearest Three Vector (NTV) and Selected Three Vector (STV). This scheme can maintain DC-link voltage within a specified tolerance value for any value of modulation index with a wide range of load variation. The results of the proposed scheme exhibits DC-link voltage variation within 0.25%, which is well below the acceptable limit. The scheme guarantees to achieve voltage balancing without any additional control. The benefits of the proposed solution over existing schemes are verified through the MATLAB simulation.

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