Electro-magnetic calculations of active part

The detailed determination of the magnetic field of wind generators using the Finite-Element-Method (FEM) is necessary for calculating inductance, peak torque, torque ripple, demagnetization risk etc.
The wind-direct engineers answer these questions with the help of the software FEMAG which is able to derive the mentioned parameters from geometrical and load inputs. Very important input parameters for these calculations of the magnetic field are the results of previous calculations of the thermal performance: possible stator current loading and magnet temperature.

Loss calculations using validated analytical procedures.
In a three-phase machine the three following kinds of losses occur:

  •  ohmic losses in the stator winding
  •  eddy-current and hysteresis losses in the stator teeth and stator yoke
  •  tional eddy-current and hysteresis losses in conductive parts of stator and rotor, also in permanent magnets

Finite-element analysis of the magnetic field
        Finite-element analysis
        of the magnetic field

Basic idea of the analytical calculation of the steady-state operation of electrical machines is reducing the complex phenomena to a simplified single-phase equivalent circuit.
Its parameters, like voltages, inductances, and resistances are estimated by simplified analytical formula from the geometry of the machine design or by determination of certain boundary conditions.

Once these parameters are available, the losses and the resulting system efficiency at different operating points can calculated rather easily.