Design Of High Frequency Induction Heating Power Supply For Water Heating Device

Induction heating is applied in metal melting and heat treatment areas more and more, this advanced heating technology with characteristics which are not available in traditional heating technology is widely used in all industries. In recent years, induction heating device in the home appliances such as small and medium-power applications are gradually increased, while the mainly applications are water-heating device. For this type of induction heating devices, the heating object is metal container or a pipe. Because of it wall generally thin, the suit operating frequency of induction heating power supply is generally higher. For the high-frequency induction heating power supply, the key is how to reduce power costs, size and improve the reliability.In this paper, the high-frequency induction heating power supply commonly used main circuit and power-adjustment method are analyzed and compared. Diode rectifier and voltage inverter are used. Integrate of the load-frequency tracking technology and full-bridge phase-shift PWM power regulation methods are introduced. Simultaneously, for the problem of high-frequency induction heating power supply load matching, LLC load-resonant circuit is used instead of the electromagnetic coupling method of high-frequency transformer. The LLC load-resonant circuit impedance and current transformation characteristics are further studied. On the base of theoretical analyses, the simulation model based on LLC load-resonant circuit and inductive phase-shifting closed-loop power control method is built under the PSIM simulation environment, and the system simulation research was implemented. Finally, based on the LLC load-resonant circuit of high frequency induction heating power supply main circuit and control circuit is designed. Using phase-shift resonant controller UC3875 and integrated PLL CD4046 integrative design control circuit, which effectively improved the stability of power supply. According to the design, an experimental platform is built, and the experiments and tests was implemented, realized closed-loop control system. Experimental results proved that this theoretical analysis and system design is feasibility and accuracy.