# Induction Coil Design Considerations for High-Frequency Domestic Cooktops
## 4 The Proposal of High-Frequency Induction Coil Design
### Simulation Results
Validation with experimental data ensured the reliability of the optimized design. The picture of the induction coil used in low-power Full-Flexi applications is given in Figure 16. The measurement results are given in Table 2. The measurement setup is shown in Figure 17.  
Figure 14: Induction coil used in conventional domestic induction cooktops: (**a**) windings; (**b**) magnetic cores. Figure 15: Induction coil used in high-frequency domestic induction cooktops such as All-Metal induction cookers: (**a**) windings; (**b**) magnetic cores. Figure 16: Induction coil used in ultra-high-frequency domestic induction cooktops such as Full-Flexic induction cookers: (**a**) windings; (**b**) magnetic cores. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Measurements with Cast-Iron Pan**} \\ \hline  & 100 kHz & 200 kHz & 300 kHz & 400 kHz & 500 kHz & 600 kHz & 700 kHz & 800 kHz & 900 kHz & 1000 kHz \\ \hline \multicolumn{6}{c}{Single-Layer Configuration} \\ \(\mathrm{Le_{q}}\) [\(\mathrm{\SIUnitSymbolMicro H}\)] & 5.03 & 4.34 & 4.01 & 3.81 & 3.68 & 3.58 & 3.50 & 3.44 & 3.40 & 3.35 \\ \(\mathrm{R_{eq,ac}}\) [\(\mathrm{\SIUnitSymbolMicro H}\)] & 1.04 & 1.60 & 2.02 & 2.35 & 2.67 & 2.89 & 3.10 & 3.31 & 3.47 & 3.68 \\ \(\mathrm{R_{eq,dc}}\) [\(\mathrm{\SIUnitSymbolMicro H}\)] & 31.2 & 19.28 & 19.3 & 19.26 & 19.19 & 19.19 & 19.21 & 19.18 & 19.18 & 19.18 \\ \multicolumn{6}{c}{Two-Layer Configuration} \\ \(\mathrm{Le_{q}}\) [\(\mathrm{\SIUnitSymbolMicro H}\)] & 20.25 & 17.71 & 16.49 & 15.75 & 15.24 & 14.88 & 14.61 & 14.4 & 14.24 & 14.12 \\ \(\mathrm{R_{eq,ac}}\) [\(\mathrm{\SIUnitSymbolMicro H}\)] & 3.81 & 6.01 & 7.64 & 8.98 & 10.11 & 11.17 & 12.13 & 13.02 & 13.87 & 14.69 \\ \(\mathrm{R_{eq,dc}}\) [\(\mathrm{\SIUnitSymbolMicro H}\)] & 37.86 & 37.85 & 37.89 & 37.87 & 37.86 & 37.85 & 37.86 & 37.82 & 37.84 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Induction coil measurements for high-frequency applications. Figure 17: The measurement setup. Core materials and high-frequency induction coil designs can significantly reduce manufacturing costs by minimizing the use of copper and core materials. This reduces labor and tool maintenance expenses, improves operational efficiency, and reduces energy consumption and cooling requirements. Advanced manufacturing techniques ensure minimal material use without compromising performance, resulting in substantial economic benefits. In addition, high-frequency operation can cause thermal and dielectric degradation, leading to reduced coil lifespan. Additionally, components like capacitors and switches may experience accelerated aging, causing premature failure and reduced overall system reliability. Electromagnetic interference can also affect sensitive electronic equipment, requiring additional filtering or shielding. Material fatigue can result in micro-cracking and eventual material failure, compromising the coil's structural integrity. To address these issues, strategies such as enhanced insulation, improved cooling systems, optimized core materials, vibration dampening, and robust design can be implemented. The block diagram of the circuit designed used in tests is given in Figures 18-20. GaN Systems GSP65 RxxHB-EVB was chosen to perform power tests. This board is specifically designed for high-power applications; hence, it contains two GS66516B GaN HEMTs in parallel. Its PCB structure is designed as an IMS (insulated material board). The power circuit is controlled as an open loop. The switching frequency was changed according to the desired power level. In the EMI filter, 2 X\({}_{2}\) safety class film capacitors (5 \(\mu\)F) and 4 Y\({}_{2}\) safety class film capacitors (22 nF) were used. In addition, there was a common mode coil wound on the MnZn magnetic core, and a differential mode coil wound on the iron powder core. Three MOVs (metal oxide varistors) were preferred as protection against high voltage. A fuse was used for protection purposes at the input. Figure 19: Series Resonant Half Bridge Converter with GaN HEMT.