The Design Of Series Resonance Induction Heatin Supply Based On MOSFET

As a new type of heating mode, induction heating has advantages of high energy utilization, precise adjustable heating temperature, local uniform heating, environmental protection and security, etc., it is widely used in metal smelting, welding, heat treatment and other industrial occasions. In this paper, the induction heating power supply is taken as the research object, the MOSFET power device is adopted for switch tube, finally the experimental prototype is made out with a rated power of lkW and a operating frequency of 30kHz.In this article, the series resonant inverter is considered as total scheme, the single phase full bridge inverter circuit is valued to be the main topology, which use the method of pulse frequency modulation (PFM) to control the inverter output different frequency signals and alter impedance of the load tank circuit, eventually to achieve the purpose of continuously adjustable power. By comparing and analyzing the state of the capacitive commutation mode and the inductive commutation mode, it is imposed that the inductive inverter should run in a weak inductive state, also known as quasi resonant condition. HEF4046B is chose as the control chip, the load current signal is compared with its voltage signal which is done 900 phase lag processing, for the sake of frequency tracking. According to the characteristics of load tank circuit, the amplitude of load current is accommodated to realize the regulation of output power. The overall control circuit consists of two independent operating loops, which is named phase-locked loop and which is called current loop, equipped with power supply circuit, MOSFET driver circuit, dead zone formation circuit, halve frequency circuit and protection circuit, etc., those working together to achieve the target of the maximum output power of the series resonant inverter.On the premise of main design parameters, electronic devices selection has been completed via calculation and practical experience, ultimately the hardware platform of induction heating has been built, experiment data and waveforms that bas been obtained verify the correctness and feasibility of the design adequately.