Design and Finite Element Simulation Research on a Brushless Air-Core Compensated Pulse Alternator With One Equivalent Pole-Pair

Abstract

As a kind of high power pulse power supply, the air-core compensated pulse alternator (CPA) is widely used in electromagnetic emission, laser weapon, pulse capacitor charging, and other fields. A brush structure or a brushless structure can be used in the air-core CPA. Because the brushless structure is more suitable for high-speed operation and has higher reliability, more and more scholars have studied the brushless structure air-core CPA. In this article, an electric excitation brushless air-core CPA which the equivalent pole-pairs number is one is proposed. The CPA adopts a brushless rotor winding designed based on the principle of magnetic field differential modulation, which can simultaneously produce two and three pole-pair magnetic fields rotating in the same direction. The rotor winding can couple the field winding and the armature winding at the same time, thus realize electromechanical energy conversion. Under the same conditions, the pulsewidth of pulse discharge current can be significantly increased by reducing the number of pole pairs of the CPA and the output energy of a single pulse can be improved. In this article, a detailed design method of the differential modulation rotor winding of the CPA is presented, and the harmonic content of the CPA is calculated by analytical and numerical methods. Finally, the finite element model is used to analyze the related performance of the CPA, and the analysis results verify the effectiveness of the design scheme.