The Simulation Research To Improve The Arc Welding Inverter Power Output Limit

Due to technical and economical avantages, arc welding inverter is considered to be the most promising welding power supply, and has been developed rapidly. However, the inverter power supply is affected by complicated factors including devices, circuit and system, and is difficult to analyze,up to now,there is no fixed method of analysis. Under the development of method of modern technology, arc welding inverter can be researched by new devices, circuit topology and methods in order to meet different welding technics demands。The subject is about the arc welding inverter power system for power output limits, the proposed measure is put forwared in the in full-bridge inverter main circuit input form to join the Buck circuit voltage pre-regulator, the closed-loop circuit through the Buck Quadratic PWM regulator to improve of arc welding inverter output power limit, the more power to optimize performance.The full-bridge inverter main circuit, the inverter controller, a voltage pre-regulator circuit and controller in the model of Buck are simulated and analyzed.At the end the simulation and experimental waveform matches.Firstly, the components and typical circuit topology of main circuit of inverter is proceed with in-depth research. The application characteristic of power electronic device such as IGBT, FRD, and transformer are analyzed, four typical circuit topologies are compared with each other, a restrain methodabout the bias phenomena of full bridge invert circuit is put forward.Secondly, constant voltage or current system is analyed respectively.Based on the constant voltage system, the current system is designed and the arc welding inverter power source, using computer simulation methods is analyzed to study it. PWM controller principle, PI regulator and the sub-frequency circuit, the current sampling method are analyzed and finally a constant voltage or current closed-loop control system simulation model of arc welding inverter power source is established and simulated. The results show that the transformer leakage inductance has an important impact on the arc welding inverter power output characteristics.Then, for arc welding inverter output power limit, the improvement method is proposed that is add a Buck voltage pre-regulator in the input of the full-bridge inverter. The form of the basic principles and steady-state of the Buck voltage pre-regulator circuit is analyed.Buck circuit inductance, capacitance parameters are calculated, Buck circuit voltage closed-loop controller is designed, and finally Buck circuit simulation model of the closed-loop system is established.Finally, the voltage pre-regulator of arc welding inverter power system simulation results show that the power output limit of power source is effectively improved,the power performance is effectively improved too,achieving the simulation of the desired purpose, for the subsequent development on a voltage pre-regulator prototype of arc welding inverter power source and making a good foundation.