Research On High Power Inverter Welding Power Supply Based On DSP

The development of welding process research,welding automation and welding flexible manufacture system has raised an ever-increasing requirement for the control precision and the flexible of the welding power source.Through a brief introduction on the present state and development of the welding inverter, this paper analyzes the drawbacks of the welding machine and blurts out the meaning of this paper.This paper researches the digital characteristics of the welding power supply and the main circuit of the full bridge high power soft-switching.Nowadays, welding machines usually apply the hard-switching as the topology,which causes the problem of higher loss and lower efficiency.The problem is much more critical when the inverter frequency is high.In a welding machine,the main circuit with the technology of the soft-switching is much idealer than the hard-switching.Firstly of all,by the theory of the soft-switching,this paper relatively analysis the advantages of the soft-switching and,analyzes the main circuit of the full bridge shift-phased zero voltage (ZVS)soft-switching.Then,the paper gives the on and off theory of the soft-switching,the model of the main circuit,key point and the parameters of the design. The disadvantages of the traditional analogue control circuit have become a blur of the welding power supply this paper applies the up-to-date control chip DSP designed for the control machine and inverter. What'more,this paper also provided the alogrithm of PI digital power controlling based on DSP,which can ensure the systerm'stable operation.On the basis of theoretical analysis,this paper also provided the sumulation analysis on power systerm,including the sumulation of PS-PWM working state and ,the sumulation of power synthesis,and the simulation of whole power systerm.In addition,a welding power supply is designed based on theoretical analysis,which are 200kW with the frequency 20kHz for the inverter. The special DSP chip of TMS320LF2407A which produced by TI Company is used as main controller of the power to simplided the system. The result is verified by experiment and the power source based on the DSP can meet the need of the welding process.