In order to realize the freedom of placing pots, the free zone induction cooker with multiple induction heating coils is gradually developing. It can perform user-customized heating of different pots, greatly improving the flexibility of using the induction cooker. In actual work, the induction heating coil in the corresponding area needs to be triggered based on the real-time position. Therefore, the correct identification of the pot position affects the working status and heating performance of the free zone induction cooker system. As a result, pot position identification has become a key factor that needs to be solved urgently. Traditional pot position identification methods are easily affected by fluctuations in external factors, require a large amount of sample data, and need to improve the accuracy and speed of pot position identification. This paper indicates that the misalignment of the pot affects the mutual inductance M between the pot and the induction heating coil, thereby affecting the impedance and current phase of the system. An identification method is proposed using the current phase to control the switch array, which achieves positioning and heating of the pot. The proposed pot position identification strategy requires a small amount of sample data, and the branch current phase is only related to the position of the pot. It is not easily affected by system voltage and current fluctuations, so the position of the pot can be judged in real-time.

Secondly, regarding the impact of pot misalignment on current and power, this paper introduces a power regulation strategy based on an adjustable capacitor circuit. Under the misaligned working condition of the pot, the disturbance observation method of maximum current search is used to adaptively adjust the adjustable capacitor. The maximum power output of the induction cooker is obtained, and the heating speed of the pot is improved. The pot position identification strategy and the power regulation strategy coordinate to ensure accurate identification of the pot position and rapid heating, which only needs to collect the current information of the system branch. Thus, the sampling circuit is simplified.

Finally, an experimental prototype of a free zone induction cooker based on three coils was built. Experimental results show that in the pot position identification strategy, the accuracy of the theoretical and experimental phases is over 96%, and the identification speed is 0.8 ms. The maximum temperature rise within three minutes is 17.3℃ using the power regulation strategy, higher than without the power regulation strategy. The proposed pot position identification strategy can correctly identify the exact position of the pot and achieve the maximum power output of the induction cooker after the power regulation strategy. The correctness of the pot position identification strategy and the power regulation strategy are verified.