Analytical Modeling of Solenoid Inductance in Intermediate-Frequency Electromagnetic Heating System

Solenoid is core component of intermediate-frequency Electromagnetic heating system, and its inductance affects power and efficiency of system. In order to accurately calculate inductance of solenoid under different working conditions, an analytical calculation model of solenoid inductance is proposed, which can consider nonlinear variation and temperature change of ferromagnetic material. First of all, magnetic and electrical properties of Q235 are tested by ring sample method and van der Pauw method, and relative permeability curves under different magnetic densities and resistivity curves at different temperatures are obtained. Secondly, based on equivalent magnetic network (EMN) solution method, analytical calculation model of solenoid inductance considering nonlinearity of ferromagnetic material is established, magnetic field distribution in solution domain is calculated, and solenoid inductance value is obtained. Influence of temperature change on solenoid inductance is considered. Finally, a set of rated power 25 kW intermediate-frequency electromagnetic energy storage solenoid is tested under multiple operating conditions to verify effectiveness of proposed analytical model.