Flying Capacitor Converter as a wind turbine interface - modulation and MPPT issues

This paper presents an application of the three-level Flying Capacitor Converter (FCC) in an AC-DC-AC (Back to Back - BtB) system interfacing a wind turbine with an asynchronous generator to the grid. The FCC operates as the machine converter (MC) while also three-level Diode Clamped Converter (DCC) is the grid converter (GC). Whole control is based on Voltage Oriented Control (VOC) and Indirect-Field Oriented Control (IFOC) methods. The discussion is focused on issue of a Space Vector Modulation (SVM) for the FCC. Moreover, to improve system stability the Power Feed-Forward was applied. To increase the effectiveness of power generation the Maximum Power Point Tracking was implemented. Experimental results confirm correct operation of the proposed control structure. Additionally, basic comparison of the FCC and DCC converters features are shortly pointed out. And finally a detailed analysis of flying capacitors voltages balancing are proven by experimental results.