| Induction heating technology has been widely used in the industry due to its environmental protection,high efficiency,safer and more controllable advantages.At the same time,there are many applications for induction heating,and the impedance values of different workpieces are quite different.In order to ensure higher working efficiency,load matching is required.Compared with the traditional LC resonant load,the LLC resonant load can achieve load matching without a transformer,and has been widely used and researched.However,the LLC resonant load may have the problem of too large phase angle of the inverter output voltage and current during the load matching process,resulting in large switching losses at high-frequency operating frequencies.In response to these problems,this paper proposes an induction heating power supply design based on the LCLC resonant load topology.On the basis of LLC resonant topology,a new LCLC resonant topology analysis method is proposed.This method converts the analysis of LCLC resonant load to the analysis of LLC resonant load.The characteristics of resonant load can be directly applied to the relevant formula of LLC resonant load.Through the analysis of the LCLC resonant load,it is proved that the LCLC resonant load has better static and dynamic characteristics in the load matching process.Compared with the load matching of the LCLC resonant load by changing the parallel capacitance and the load matching of the LLC resonant load by changing the series inductance,it has a smaller inverter output voltage and current phase angle,so the switching loss is smaller.At the same time,changing the capacitance for load matching is also easier to operate.After that,the main circuit topology of induction heating is given.On this basis,the load parameters are designed and the control system based on TMS320F28035 is designed,including inverter phase lock control,chopper voltage regulation control,protection circuit and man-machine interface.Communication circuit.Finally,the induction heating power supply prototype was built,including the design of the main circuit parameters and device selection.On the built prototype platform,the LLC resonant load and LCLC resonant load experiments were carried out.The analysis of the experimental results verified that The correctness of theoretical analysis and the rationality of parameter selection. |
