Efficiency Comparison of Power Electronic Converters Used in Grid-Connected Permanent-Magnet Wind Energy Conversion System Based on Semiconductors Power Losses

Abstract

An efficiency comparison of power converters is presented for a permanent magnet generator based grid-connected wind energy conversion system. The power converters examined are: the intermediate boost converter (IBC), the intermediate buck-boost converter (IBBC), the back-to-back converter (BBC) and the matrix converter (MC). The aim is to determine which power electronic converter yields the highest efficiency in terms of power losses of the semiconductor devices with the varying wind speeds. In view of this, a furled wind turbine model is developed that generates power for different wind speeds. Afterwards, a relation between the wind speed and power loss is established to evaluate the efficiency of the power electronic converters for discrete wind speeds. The power loss model presented in this paper has taken into account the conduction and switching losses of the semiconductor devices within each converter. Simulation results are presented showing the power loss characteristics with the variation in wind speeds. Finally, with regard to the global efficiency for the power electronic converters of the considered wind speed regime, the IBC is found to be the most favourable choice considering the typical wind conditions encountered by a wind energy conversion system operating at the kWatt level.