Low-speed Permanent Magnet Generator Characteristics Research

As the wind energy utilization soon developly, low-speed permanent magnet generator is used more and more popular. Current research on the characteristics of low-speed permanent magnet synchronous generator mostly focused on the improvement on the structure and system optimization design, and the analysis on the generator running performance and how to optimize design are less.Firstly ,analyzed the four kinds of permanent magnet synchronous generator rotor structure and how they affect the property of low-speed permanent magnet generator, thus determined which kind of structure can effectively reduce the volume of a generator, and analyzed the working principle of the low-speed permanent magnet generators, the armature reaction of unload and load, and the equivalent magnetic circuit of permanent magnet, and made a pave for the subsequent analysis of the magnetic energy calculation.Secondly, analysed magnetic induction intensity changes produced by different shape permanent magnets in the space of magnetic field. Based on Biot-savart law, using the numerical analysis calculated magnetic induction intensity of three different shapes which include rectangle.cylindrical and tile model permanent magnet with the same material, same size and same height of the magnetic field, and used Matlab software to establish M file to get magnetic induction intensity changes and trend curve.Again, listed the characteristics of the low-speed permanent magnet generator parameters and made a property calculation. The parameters conclude calculation parameters and structure parameters, analyzed the influence of these parameters on the generator performance,and made simulation for some of the parameters , got the effect direction on the property of generator when these patameters were changed ; Meanwhile made calculation for the permanent magnet generator ,such as permanent magnet flux calculation, quadrature-direct axis inductance calculation and motor resistance R calculation.Finally , established the mathematical model of permanent magnet generator in the Matlab/simulink. and carry on the simulation analysis, according the model, the input of external model was generator rated torque, and the output was three-phase voltage and three-phase current? rotational speed and electromagnetic torque. Set the parameter input interface, input motor data and characteristic parameters, simulated the respective curve of three-phase voltage Uabc?three-phase current Iabc?rotational speed n? electromagnetic torque Te and rotor position angle theta of three different shape permanent magnet ,so as to analysed three kinds of shape can effectively improve the air gap magnetic flux density within the permanent magnet generator, thus reduced the volume of the low-speed permanent magnet generator, and decreased the cost of generator.