Energy management strategy for a direct AC-AC modular multilevel converter in YDY coupling

In this article an energy management strategy for a Modular Multilevel Converter is proposed, this converter is operating as a direct frequency changer. It is connected in three-phase configuration and the developed control strategy depends only on measurements made at the converter site without using neutral wire parameters information, which is convenient for high power applications. Developments are conducted to use the converter in Offshore System working at Low Frequency, but also it can interconnect 50 with 60 Hz systems. Simulation results prove the efficiency of the control strategy with almost inexistent low frequency harmonics without using any filter.