Multilevel Current-Source Converter based STATCOM using Minimum DC Current Level

AC drives based on current-source converters (CSC) present an interesting alternative for medium voltage motors, because of high quality of both AC input currents and load voltage waveforms. This kind of power converters allows avoiding wave reflection problems that are typical of voltage-source inverters. However, the use CSC in active power filters is limited by power losses caused by the DC current. In this work we study the use of multilevel current-source converter based STATCOM, using minimum DC current level in each converter. For the above, the STATCOM current level required to compensate both load reactive power and STATCOM losses is computed, using the highest modulation index possible. Mathematical analysis corroborated by PSIM simulations, shows that it is possible to reduce power losses in the overall equipment, by increasing the number of converters in the STATCOM.