What determines the required bandwidth of current sensors in an electric motor drive?
The required bandwidth must be great enough so faults are responded to quickly. Remember that solid state components are not as forgiving as motors when it comes to overloads.Newer devices like IGBTs have surge current ratings for about 10 microseconds and the older SCRs had surge ratings of about 10 milliseconds. When current sensing is part of the control loop which is common practice stability can be a real issue. Higher bandwidth is better from a control loop stability viewpoint.