Abstract: During the operation of an induction heating power supply, variations in load parameters can cause power fluctuations and deviations between the operating frequency and the inherent resonant frequency. To address these issues, a combined control strategy integrating phase-shifted PWM power regulation and frequency tracking technology is proposed for simultaneous power and frequency adjustment. Given the complexity of load impedance variations and the difficulty in establishing an accurate model, a third-order linear active disturbance rejection control (LADRC) is designed to regulate the power adjustment process. To mitigate significant switching losses under high-frequency operation, an LCLC resonant load based on electrostatic coupling is proposed to achieve impedance matching. A detailed power analysis of phase-shifted PWM power regulation applied to the LCLC resonant load is provided. Finally, MATLAB/Simulink simulations demonstrate that the third-order LADRC outperforms traditional PI control in scenarios involving power step changes and load transients, while also validating the accuracy of the power analysis.