Improved control strategy for modular 2MVA AC/AC power converter

A 2 MVA 5060 Hz high performance parallelable frequency converter for harbor application was designed, fabricated, and tested. To increase output power, a smart digital control scheme was implemented; it can parallel two or more power converters with optimum current sharing among them and a good robustness to malfunctioning. Moreover the control can identify a faulty converter and, switching it off, it assures system continuous operations in derating conditions. This attractive feature is worth from availability point of view since it allows restoring full operating conditions without plant shutdown. The control strategy was developed and simulated in MATLAB Simulink/PLECS environment and then tested on a scaled prototype. Once a satisfactory agreement between simulation and prototype was obtained a full size system composed by two 2 MVA converters was built. Measurements performed on full size system confirmed the achievement of the specifications.