Control of neutral point deviation in 3-level NPC converter with selective harmonic elimination, applied in wind generation systems

In the multi-MW wind turbine market, the maximum power rating of a commercial wind turbine has been increased more than 5MW with a view to generate more power from Wind Power Sites [1]. The three-level neutral-point-clamped voltage-source converter has been highly applied in wind generation system. Despite the advantages, the capacitor voltage unbalancing in NPC converters has become a burning issue and has invited intensive research to address this problem. This work proposes a method to overcome this problem with the selective harmonic elimination pulse-width modulation (SHE-PWM), in wind generation systems. Real world results are presented using Digital Signal Processor (DSP) to verify the real applicability of the proposed method.