How can I avoid spike that happen in derivative block

This model is base on this equation VH(Volt) = IH(Amp)*RA(Ohm) + LH(Henry)*di(t)/dt(A/s) + VD(V)

Answer 1

[Shiny S]

If you want to eliminate this spike you can use saturation block there you can set the limit of input signal to the upper and lower saturation values otherwise you can use median filter from DSP System Toolbox in simulink library.