Research On Dual-stator Axial Flux Permanent Magnet Generator With Dual Six-phase For AC-DC Hybrid Power Supply

AC-DC power supply systems are widely used in independent platforms with limited volume and strict requirements on the weight of power supply,such as aerospace,ships,mobile communications,and offshore oil exploration platforms.The conventional AC-DC generator types are mostly radial flux motors such as asynchronous generators,electric excitation synchronous generators,and permanent magnet synchronous generators.Compared with the radial flux machine,the axial flux machine has better heat dissipation and higher power density than the radial flux machine due to its structural characteristics which makes it more suitable for space-limited occasions.Based on this feature,this thesis designs an AC-DC axial flux generator with a dual-stator and single-rotor structure.Using the characteristics of two independent windings on each of its two stator disks,the purpose of AC-DC power generation is realized.The following work is carried on in this thesis:Firstly,according to the requirements of high reliability and low DC voltage ripple of AC-DC generator,an axial flux permanent magnet generator with dual six-phase winding is proposed.The AC winding and the DC winding are designed as six-phase double star winding shifted by 30°;the regular pattern of the magnetomotive force of six-phase double star winding shifted by 30° is studied,and uncontrolled rectification can generate a huge number of high-order harmonics,the expression based on the full harmonic magnetomotive force of the stator is deduced by the analytical method,which provides a theoretical basis for improving the performance of the machine.Secondly,the analytical calculation of the dual six-phase winding axial flux permanent magnet machine is researched.In view of the three-dimensional distribution characteristics of the air-gap magnetic flux of the axial flux machine,this thesis calculates the air-gap magnetic field,no-load back EMF and flux linkage of the machine based on the magnetic equivalent network method under the consideration of iron saturation and flux leakage.The preliminary size and electromagnetic parameters of the machine are obtained,and provide a reference for the optimization of the finite element.Finally,the operating performance of dual six-phase axial flux permanent magnet generator providing AC and DC power is researched.The no-load performance of the designed machine under DC side no-load,the AC side with a rated load alone,the AC side no-load,the DC side with rated load alone,and the AC-DC side with rated load at the same time is analyzed by commercial finite element analysis;for two sets of windings that are independent on the electric circuit but coupled on the magnetic circuit,the mutual influence between the two sets of windings on the AC side and the DC side is studied;the influence of different winding forms on machine output power,loss,torque ripple and DC voltage ripple are explored.