Optimal selection of the average capacitor voltage for modular multilevel converters
2013 (English)In: 2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013, IEEE , 2013, 3368-3374 p.Conference paper (Refereed)
Variable-speed drives have reduced voltage requirements when operating below the base speed. In a modular-multilevel-converter-based (M2C-based) motor drive it is then possible to operate with reduced voltage in the submodule capacitors, than at the base speed. In this sense, a greater capacitor-voltage ripple can be accommodated, without exceeding the maximum peak-capacitor voltage. This paper presents an analytical investigation for the optimal selection of the average capacitor voltage for M2Cs, when the motor is operating with rated torque, below the base speed. This method does not require any power exchange between the converter arms, so it keeps the conduction losses at the minimum level. Additionally, the method decreases the switching losses, due to the decreased capacitor-voltage level. The overall ratings of the converter remain the same as in the base-speed operation. It is shown that this method can be applied at a speed range between the base speed and down to approximately one third of it, i.e, an operating range that covers the requirements for typical pump- and fan-type applications. The results obtained from the analytical investigation are experimentally verified on a down-scaled laboratory prototype M2C.
Place, publisher, year, edition, pages
IEEE , 2013. 3368-3374 p.
Capacitor voltage control, medium-power variable-speed drives, modular multilevel converters, optimization
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject SRA - Energy
IdentifiersURN: urn:nbn:se:kth:diva-139082DOI: 10.1109/ECCE.2013.6647143ISI: 000345216903093ScopusID: 2-s2.0-84891079383ISBN: 978-147990335-1OAI: oai:DiVA.org:kth-139082DiVA: diva2:683626
5th Annual IEEE Energy Conversion Congress and Exhibition, ECCE 2013; Denver, CO; United States; 15 September 2013 through 19 September 2013
QC 201402052014-01-052014-01-052016-02-25Bibliographically approved