Secondary current detecting device of medium frequency resistance spot welding based on rogowski coil

In order to detect welding current better and improve welding quality of resistance welding,the secondary current detecting device of medium frequency resistance spot welding was designed based on Rogowski coil. The parameters of Rogowski coil were determined according to the characteristics of welding current. The errors of Rogowski coil basic integration circuit were analyzed. A symmetrical compensation circuit was designed. Test results show that the symmetrical compensation circuit effectively overcomes the basic integral circuit of the integrated drift and nonlinear problems. The current detecting device can measure real-time welding current accurately and stably. What’s more,compared with other welding current detecting devices,the current detecting device is smaller in size,more convenient in installation and lower in cost.