The Structure Design of PMG(permanent Magnet Generator)

    The excitation magnetic field of a PMG is generated by a permanent magnet, which is the main difference with the excitation generator. The permanent magnet is not only the magnetic source in the motor but also the component of the magnetic circuit. The performance of permanent magnets not only related to the manufacturing process, but also related to the shape and size of the permanent magnets, the magnetization method relates to the magnetizer capacity, and the dispersion of specific performance data is very big. Moreover, the magnetic flux and magnetomotive force that the permanent magnet can provide in the motor also vary with the material properties, dimensions, and motor operating conditions of other part  in magnetic circuit.

    In addition, the magnetic circuit structure of permanent magnet generator is various, the leakage magnetic circuit is very complicated and the leakage flux accounts for a large proportion, while the ferromagnetic material portion is easy to be saturated, and the magnetic permeability is nonlinear. These all increase the complexity of the PMG electromagnetic calculation, thus the calculation results accuracy is lower than the electric excitation generator. Therefore, new design concepts must be established to reanalyze and improve the magnetic circuit structure and control system; modern design methods must be applied to study new analytical calculation methods to improve the accuracy of design calculations; advanced testing methods and manufacturing must be studied and adopted.