Study on the Principle and Performance of a Novel Synchronous Cascaded Air-Core Brushless Compulsator

This article proposes and studies a new type of air-core compulsator (compensated pulse alternator) for electromagnetic railgun, which realizes the brushless rotating-field electric excitation based on an axially cascaded exciter. The characteristics of the nonrectifier and inverse connection sequence of rotor full pitch winding make it different from the previous cascaded synchronous generator or doubly fed generator. Therefore, it can not only ensure a brushless and slip-ring-free structure, but also the advantages of high rotational reliability and excitation efficiency. The operation principle and design method are given first, and then the key application performance indexes such as self-excitation process, output power, energy storage density, and energy conversion efficiency of a scaled prototype are analyzed in detail. The study results show that the output power density of the scaled prototype can reach 629 MW/m3, and pulse energy storage density can reach more than 1.58 MJ/m3, which verifies the feasibility of the novel compulsator in principle and implementation, as well as advantages over the traditional hybrid energy storage scheme (battery and capacitor) in volume and weight. The relevant conclusions have positive reference significance for the lightweight and miniaturization of pulse power supply (PPS) for electromagnetic energy equipment.