The Inductance Computation for the Passive Compulsator

In order to decrease the internal impedance of the passively compensated pulsed generator (or passive compulsator) and enhance its power density, air gap windings are generally selected as the armature winding of the passive compulsator, for its inductance is much lower than that of the general embedded windings in the machine slot. Due to that the peak power of an electromagnetic launcher system driven by a compulsator is simply determined by system impedance and the output voltage of the compulsator, it becomes necessary to gauge the total inductance of the air gap windings accurately with straight forward calculation, while neglecting the easily obtained resistance parameters, particularly in its design period for electromagnetic launchers. By taking into account the flux compression effects generated by the eddy current of the continuous conductive shield in the compulsator, the magnetic field of the armature coils in the air gap of generator is analyzed by Ampere´s law. The analytical solution to the inductance of armature air gap coil is deduced. This one equation solution is used for re-designing a 25 MW compulsator with the final calculation result: 4.04 muH. The measurement on the compulsator (4.05 muH) verified the accuracy of the analysis equation.