This paper discusses the design and electromagnetic analysis of an induction-type coilgun system with a pulse power module. The voltage, current, force, velocity, acceleration, and efficiency of the coilgun system were analyzed using the finite-element method (FEM). A simplified FEM model was developed for ensuring both accuracy and rapid calculation times. Based on the results of the electromagnetic analysis, the geometry of the coilgun system was defined with the Taguchi method. The coil-type armature was applied for increasing the mutual inductance and projectile force. The electromagnetic analysis results were also compared with the analytical analysis results. The designed coilgun system was found to exhibit high energy efficiency and safety of the system. The design specifications and analysis results concerning the coilgun can, hence, be effectively utilized to develop a large-scale multistage induction-type coilgun system.

This paper presents some discussions and findings related to the development of the capacitor bank-based pulsed power supply module (PPSM) for an electromagnetic induction coilgun (EIC). Three PPSMs were designed for a three-stage EIC to launch a 21.68-kg projectile at a minimum velocity of 20 m/s. The energy of the PPSM in the first, second, and third stages was 200, 100, and 100 kJ, respectively. Two light-triggered thyristors (LTT) were used as the main switches of the module. The synchronous behaviors of the series LTT, dump circuit, laser diode driver circuit, and protection scheme are analyzed and discussed. The PPSM was built and tested as an EIC system. The simulation results of the PPSM were in agreement with the experimental results. The peak current was about 42 kA at a maximum voltage of 10 kV as in the simulation. The maximum current in the 4-kV launch experiment was 16.47 kA. The velocity of the projectile was more than 25 m/s, which is consistent with the design goal.

Since 2016, Hanwha Defense Corporation has been working on applying electromagnetic launch technologies such as induction coilguns to cold-launch systems that can launch guided missiles. First, a design procedure of a multistage coilgun system based on the pulsed power driven by capacitor banks was developed using the Taguchi method, and a laboratory-scale three-stage coilgun capable of launching a 21.68-kg projectile at a maximum speed of 27.5 m/s was built and the results of the experiment were announced in 2018. In this article, we design, fabricate, and present the experimental results of a pulsed power-based four-stage induction coilgun using the proposed procedure to prove the validity of the electromagnetic launch technology for heavy missile launch. In this experiment, a 100-kg projectile was fired under 4-kV charging conditions, the maximum speed of the projectile was 25 m/s or more, and an efficiency of 15% was achieved without considering the mass of the armature. In this study, by accelerating a 100-kg projectile to 27 m/s, the feasibility of an electromagnetic launcher developed for heavy missile launch was verified.

This paper presents a new capacitor bank topology for a pulsed power system to improve the efficiency of multistage synchronous induction coilgun. In the proposed method, a switch, such a gate turn-off thyristor, is inserted in parallel to a crowbar diode and load to generate an attractive force between the next stator and the armature. A mathematical model was developed, and finite-element method simulations were conducted to verify the proposed topology. The results show that the proposed method improves the energy efficiency and launch velocity. The improvement in energy efficiency is confirmed from the simulation results of a three-stage synchronous induction coilgun.

Electromagnetic induction coilgun systems have been receiving great attention, recently, due to the advantage of noncontact between the stator and armature coils. Several studies present the simulation and analysis of the coilgun system by using the finite-element method. However, there are still deficiencies in current modeling studies of the coilgun system. This paper presents a design of a multistage pulsed power induction coilgun system using the Taguchi method to maximize its efficiency and reduce the time and cost of the design process. A coilgun system is analyzed and designed using a state-space equation system. The Taguchi method is applied in order to evaluate and determine the geometric variables, the layer, turn layer numbers for both the stator and armature coils, and the trigger positions of each stage. Then, a 2-D finite-element model of the coilgun system using the MagNet program was developed to compare the design and analysis results. The energy efficiency of the three-stage coilgun system is 31.3%, and this is expected to increase with the increase in the number of stages.

This paper presented a comparison study result on the design of direct-driven type superconducting wind power generators using MgB2 and YBCO wires. Detailed features of MgB2 and YBCO wires were investigated and 4 MW superconducting generators were designed using MgB2 and YBCO wires. The magnetic field distributions of the generators were analysed using a 3D finite element method program. The total length of the wires, the volume, and weight of the designed generators were compared. As a result, the weight and volume of the generator using the YBCO wire were lighter and smaller than the generator using the MgB2 wire. The required length of the MgB2 was shorter than the YBCO wire which is much more expensive than MgB2 wire. It is therefore necessary to select the appropriate superconducting wires considering cost, weight, and volume issues when designing superconducting generators.