Research On Soft - Switching Power Supply Based On DSP

The inverted spot welding power supply is one of the important development direction of the resistance welding. The soft switching technology can not only reduce the switching loss and electromagnetic interference of power switch tube,but also can reduce the sensitivity of the parasitic parameters of the whole system circuit, then the stability, reliability and power efficiency of the inverted spot welding power supply can be improved.The article will focus on the inverted spot welding power supply with the technology of soft switching.In this paper, the electrical principle of the ZVS-PSFB converter was detailed analyzed.Compared with the main three kinds of the new soft switching technology at present,and considering the characteristic of the inverted spot welding power supply, we adopted a new soft switching topology with a auxiliary network. This circuit can assist the lagging leg to achieve soft switching at light load and broaden the range of ZVS. Each working condition of this new ZVS technology were analyzed and the relationship between the main parameters were also deduced.The simulation analysis was carried out by using saber which is a simulation software.Then the influence rules of the parallel resonant capacitors and the auxiliary network on the soft switching range were summarized. Through the theoretical analysis and simulation results, the main circuit with the new ZVS technology of the inverted spot welding power supply was designed, given the specific parameters of its main components.A new ZVS topological experimental prototype with auxiliary network is designed, and some experiments are carried out.In the control,We choosed TMS320F28335 as the control core which is a DSP chip of the series of TI C2000. Its peripheral circuit, voltage and current sampling circuit, IGBT driver circuit, keyboard circuit and LCD display circuit were designed,and then the design idea of the software system were described.Our test shows that the inverted spot welding power supply with new soft switch technology can broaden the soft switching range of the lagging leg, making the lagging leg also can realize the soft switching at lighter load.