Induction heating is a technology that uses heat generated by resistance when a high-frequency current is applied to a coil. An electric range using this is called an Induction Heating (IH) electric range. IH electric ranges are being widely applied in commercial products recently because they have higher thermal efficiency performances than other methods. The performance of a heating coil of an IH electric range greatly varies depending on the shape and number of coils. Thus, research on optimal coil shape and number according to product shape is required. Therefore, this study aimed to design an optimal heating coil at the set temperature of an electric range product. Target temperature was set to the temperature that a commercial stainless-steel container could withstand. The thickness of the coil copper wire, the number of windings, the applied voltage, and the frequency were set as design variables. A sensitivity analysis was performed to check the influence of each design variable on coil temperature. Based on this, optimal design was performed using the response surface method. Electromagnetic field-thermal analysis was performed with the designed coil and a very approximate result was obtained with a 0.07% error from the set target temperature.

This study performed high-frequency heat treatment experiments and simulations of the park gear of an automobile transmission. The heating temperature and hardening depth were measured during high-frequency heat treatment. Moreover, by applying the resonance RCL circuit, the current value of the coil during high-frequency heat treatment, the electromagnetic and heat transfer material properties dependent on the temperature, and the phase transformation function were all applied to the simulation. In the high-frequency heat treatment experiment, the heating temperature was 977.4℃ and the 1st direction hardening depth was 1.5 mm, the 2nd direction hardening depth was 3 mm, and the 3rd direction hardening depth was 2.5 mm, and the reliability was verified by comparing the simulation heating temperature of 1,097℃ and the 1st direction predicted hardening depth of 1.6 mm, the 2nd direction predicted hardening depth of 2.8 mm, and the 3rd direction predicted hardening depth of 2.7 mm. The error rate of the heating temperature results was 12.2% whereas that of the hardening depth results was 7.1%.

In the heating and drying system using microwaves, an optimal design method was presented to effectively shield microwaves leakage between the door and the cylindrical applicator. In order to protect the human body from leaking microwaves, it is necessary to keep the intensity of microwaves below 5 mW/cm². The door part adopts a choke structure and includes a number of design factors, such as, fin shape, slit shape, and a gap between the applicator and the door. The geometry was optimized by design of experiments, applying full factorial design and response surface method in a 4-factor, 2-level design. The results obtained by ANSYS HFSS analysis were applied to the intensity of microwave leakage according to the change of the design factors. The shape of the choke structure was optimized using Minitab, a statistical program. The microwave heating and drying system was manufactured based on optimal design value and the leakage of microwaves between the door and the applicator was measured. We confirmed that the experimental values were consistent with the simulation values.