Performance Assessment of a Wind PM Generator-Rectifier System by an Integrated FEM-Circuit Model

The paper deals with the evaluation of energy production by means of small-medium rated wind generators using surface PM synchronous machines. A methodology is developed to determine the electrical operating point of a wind generator-rectifier system, matching the turbine shaft power on the one hand and the total losses and the output power of the electrical generator on the other hand. The methodology uses a general circuit model to determine the phase currents and the output characteristics by means of a sequence of 2D non-linear magnetostatic FEM analyses at no-load. The iron and PM losses are estimated by means of a further procedure, in which the magnetic field time variation in the magnetic circuit is reproduced by using the same FEM solutions. The methodology has been applied to analyze the performance of a 20 kW wind generator by a parametric analysis involving the PM sizes.