Magnetic and conductive shielding for air‐core pulsed alternators in railgun systems

Abstract

Magnetic and conductive shielding are the alternative choices for air-core pulsed alternators (air-core CPAs) in electromagnetic railgun systems. Because of the absence of ferromagnetic materials in the air-core alternators, the flux density inside can be 3-5 T. Electromagnetic shielding is needed to protect the surrounding electronic devices and humans from exposure to high oscillating magnetic fields. Electromagnetic shielding changes the distribution of the magnetic field and the corresponding winding inductance, as well as the output performance of the powering the railgun. This paper mainly concentrates on a GW-scale, fourphase air-core CPA-based railgun system. The magnetic and conductive shielding are adopted correspondingly. The effectiveness of shielding and electric performance are investigated in detail. Using the co-simulation method, an instructive comparison is made between the magnetic shield and the conductive shield, which is meaningful to the design of the electromagnetic shielding of air-core CPAs for railgun systems.

Analysis of Influencing Factors of Armature Interception Effect in Single‐Stage Coil Launcher

“…To simplify the analysis, a singlestage coil is discussed. A capacitor bank is taken as the power supply of the driving coil [14,15]. The equivalent circuit coupling model of the synchronous induction coil launcher is established as shown in Fig.…”

Outer Rotor Permanent Magnet Passively Compensated Pulsed Alternator for Electromagnetic Railgun System

“…Due to the higher speed of CPA which can reach to more than 10000 rpm, the compensating unit positioned outside the inner rotor is easy to deform under the centrifugal force generated with the high-speed rotation of rotor, which will bring the vibration and noise, even cause the contact fault between the air gap of stator and rotor, and lead to the damage of the CPA. In addition, the internal rotor structure usually needs an additional flywheel to increase the energy density [17,18]. e electric excitation mode is adopted for most of the CPAs, where the excitation magnetic field is generated by the current in the excitation winding.…”