Research On Bridgeless PFC System Of Resistance Spot Welding Inverter Power Based On DSP

With the rapid development of power electronics technology and power switching devices,basic technologies such as circuit reliability of resistance spot welding inverter power sources have become mature.At the same time,the European Union issued the IEC-62135-2 standard,which puts forward new requirements for the electromagnetic compatibility of resistance welding equipment.Therefore,the power factor correction technology of resistance spot welding inverter power supply is gradually being accepted by academic and industrial circles at home and abroad.attention.Since 2009,China has gradually adopted the GB31251.2-2014 resistance welding equipment part 2: electromagnetic compatibility requirements standard based on the IEC-62135-2 standard,further standardizing the resistance welding equipment market,thereby enhancing the domestic resistance welding power supply technology competition force.Therefore,it is of great significance to study the power factor correction technology of the resistance spot welding inverter power supply.In this paper,based on the working characteristics of the resistance spot welding inverter power supply such as high power,variable load and short welding time,a bridge-based PFC system for resistance spot welding inverter power supply based on DSP is studied.The main circuit of the system adopts a dual-diode bridgeless Boost PFC topology.The control circuit uses a PIC32MK1024MCF064 with DSP core as the main control chip.It samples the inductor current,output DC voltage and input voltage signal.It is realized by analyzing and processing the signal and real-time control.The system responds quickly and dynamically.The system adopts the average current control strategy in CCM mode,through fast error correction,improves the power factor of the resistance spot welding inverter power supply,and reduces the harmonic distortion rate of the grid side.Based on the above control strategies,write control programs,including system soft start,AD signal sampling,digital dual-loop PID control,PWM modulation output and other functional modules,to achieve the digital control of the bridgeless PFC system.Based on the above work,based on the JYD-01 L resistance spot welding inverter power supply,completed the construction of the resistance spot welding inverter power supply bridgeless PFC system experimental platform,and finally carried out the power factor correction experiment for the projection welding process with fast dynamic resistance change.The experimental results show that the power factor correction effect of the bridge welding PFC system of the resistance spot welding inverter power supply is good.The power factor can reach0.992 under full load,the harmonic distortion rate on the grid side is 7.27%,and the harmonic current values on the input side also complies with relevant national standards.