The Windings Inductance Calculation of an Air-Core Compulsator

An air-core compensated pulse alternator is a compact pulsed power supply for electromagnetic launchers. The structures of these machines are designed distinct from that of traditional synchronous generators. The materials used to build rotor and stator are nonferromagnetic instead of the traditional ferromagnetic materials. They are usually designed slotless to enhance the stiffness of coupling of windings. As a result, the method of windings inductance calculation is different from that of the traditional ones. The parameter of windings inductance of air-core compensated pulsed alternator plays an important role in the machine design and performance simulation. Therefore, an analytical method to calculate the windings inductance is needed. In this paper, two analytical methods, a 2D method and a 3D method, are used to calculate the windings inductance. As to the special figuration of these windings, a 2D analysis method based on the parallel two-conductor line electromagnetic theory and the superposition principle is employed to calculate the self-inductance and the mutual-inductance of them. Then, a 3D analytical method based on the theory of mutual-inductance between two parallel rectangular loops whose central axes are the same is presented. Finally, a finite-element method based on the software ANSYS is also used to calculate the inductance, which is used to verify the accuracy of the analytical methods.