Modular multilevel converter with DHB energy-balancing channels for medium-voltage adjustable-speed drives

The Journal of Engineering

Ahmed M. Massoud¹  Shehab Ahmed²  Derrick Holliday³  Barry W. Williams³  Mohamed S. Diab³ 

[1] Electrical Engineering Dept., Qatar University;Electrical and Computer Engineering Dept., Texas A&M University at Qatar;Electronic and Electrical Engineering Dept., University of Strathclyde;

关键词: bridge circuits;    power capacitors;    capacitors;    variable speed drives;    voltage control;    power convertors;    switching convertors;    out-of-phase alternation;    traditional MMC topology experiences;    motor phases;    medium-voltage high-power variable-speed drives;    energy rebalancing;    energy exchange;    modular multilevel converter configuration;    medium-voltage adjustable-speed drives;    DHB energy-balancing channels;    converter topology;    rated speed;    SM capacitor voltage ripple profile;    wide SM capacitor voltage fluctuation;    MMC system stored energy;    bidirectional power transfer;    counter-balances arm ripple-power;    MMC-leg;    opposite SMs;    dual half-bridge modules;    MMC configuration decouples this ripple power;    lower arms;    upper arms;    fundamental ripple power;   

DOI  :  10.1049/joe.2018.8082

来源: DOAJ

【 摘 要 】

This paper presents a modular multilevel converter (MMC) configuration that utilises energy exchange between sub-modules (SMs) of upper and lower arms, for energy rebalancing. The configuration is applicable to medium-voltage high-power variable-speed drives with any number of motor phases, where the traditional MMC topology experiences challenging shortcomings. With the out-of-phase alternation of the fundamental ripple power in upper and lower arms, the proposed MMC configuration decouples this ripple power by employing dual half-bridge modules linking opposite SMs in upper and lower arms of the same MMC-leg. This counter-balances arm ripple-power through bidirectional power transfer between opposite SMs, resulting in a reduction in the SM capacitance and the MMC system stored energy. The proposed MMC configuration solves the problem of wide SM capacitor voltage fluctuation, especially at low operating frequencies, where the SM capacitor voltage ripple profile is almost constant, independent of the operating frequency. Therefore, the configuration is able to drive multi-megawatt machines from stand-still to the rated speed, at rated torque. The operation of the proposed converter topology is elucidated in detail, and its effectiveness is verified through simulation and experimentation.

【 授权许可】

Unknown