Analysis and reduction of coil temperature rise in electromagnetic forming

How to reduce the temperature rise of coil winding is an important issue for improving the production and lifetime performance of the tool coil in electromagnetic forming system. To address the problem, this paper proposes a new discharge circuit configuration with a crowbar circuit to control the discharge current flowing in the tool coil and then to reduce the Joule heating generated without affecting the forming efficiency. A detailed numerical analysis of the mechanism of the temperature rise reduction was first carried out, and then numerical simulation and experimental investigation of the effects of the crowbar circuit on the coil current and surface temperature rise were investigated. The simulation results show that the Joule heating in the coil winding can be reduced from 4.62 kJ to 2.07 kJ when a crowbar circuit with a resistor of 0.3 Ω was applied, and the corresponding temperature rise in the coil can also be effectively reduced. Meanwhile, the experimental results show good agreements with the simulation results, further verifying the effectiveness of the proposed method.