Research And Design Of The Induction Heating Power Group Based On A Decoupled Control Of Co-frequency And Co-phase Output

Induction heating power is a prominent application of environment-friendly heatingpower. To response to the constantly increasing demand for high power and frequency,this dissertation puts forward a project in the multi-to-one heating mode that11induction heating powers work as a union, as well as functioning properly andindividually. Besides fulfilling the performance demand and proposing a decoupledcontrol based on co-frequency and co-phase output to reduce the electromagneticinterference, this thesis analyzes the nowaday situation and trend of induction heatingtechnology with the comprehensive of electromagnetic induction heating theory and theapplication of modern power electronics and microprocessor technology to complete thefinal design of the system.Firstly, by comparatively analyzing the topology of main circuit and the poweradjustment approach of different powers, this project adopts the topology of voltageseries resonant and the power adjustment method of increasing frequency of pulse widthphase shift. And then this thesis gives the interpretation of the output decoupling controlprinciple, poses a theory to suppress the electromagnetic interference in the powergroup, analyzes two realization methods called fixed frequency mode andmaster-branch mode to achieve the co-frequency and co-phase output, and finallydesigns a kind of circuit based on the current transmission and differential transmissionto reduce electromagnetic interference during the transmission.Secondly, the composition diagram of the single system loop of the inductionheating power is given and the composition and function of the various components areelaborated, combined the device selection by parameter calculation is determined.Besides, the check sampling circuit for signal is designed, and through the analysis ofthe frequency tracking, PLL road of the same frequency is designed. After that, thesoftware control process is introduced, and the design of the protection control circuit isgiven.Thirdly, the basic concepts of the harmonic and the power factor are introduced, andthe harm caused by the harmonic is described. To prevent the harm of the harmonic and further improve the power factor, the technology of the line filter, three-phase controlledrectifier bridge and soft switching are taken. Then IGBT snubber circuit, the poweredisolation between the system modules and the suppressed harmonic interference bymeasures like outputting the interference of decoupling are designed.Finally, this thesis presents and analyzes each part of the debugged waveforms suchas phase-locked loop, the inverter circuit and the output load of the single power,summarizing and analyzing the decoupling waveform and on-site test data ofco-frequency and co-phase output from the two powers. The feasibility and rationalityare verified. The induction heating power decoupling group of co-frequency andco-phase is finally completed after sever al corrections and improvements.