Analysis and Control for Wind Energy Conversion System with Five-Level Neutral-Point Clamped Inverter

Abstract

Multi-level neutral point clamped inverters allow for higher resolution AC outputs and increase the overall efficiency, but higher-level inverters also increase cost exponentially with level and control of the neutral point voltage becomes more difficult through processor capability. The method used within this paper seeks to reduce algorithm complexity by using a two-level space-vector pulse width modulation algorithm-based method while simultaneously implementing a neutral point voltage control embedded within to ensure signal integrity to drive a five-level neutral-point clamped inverter. The increased level of the neutral-point clamped inverter will allow for higher switching efficiency by reducing voltage stress on the switching devices and more stability through reduction of harmonics in the AC output waveform. Results from simulation show the increase in resolution of the AC outputs to both the utility grid and the permanent magnet synchronous generator when compared to a three-level neutral-point clamped inverter using a standard space-vector pulse width modulation switching scheme.