Type 2 or 3 Compensator for LDO
What methods can we use in order to stabilize our Error Amplifier?


You analyse the loop gain and phase. You do this by breaking the feedback so that you can apply an input and look at the corresponding output amplitude and phase. This can be tricky on high gain systems (such as op-amps) but that's the most successful method of determining the phase margin of a system.

Basically, if the output becomes in phase with the input at a point (or points) in the spectrum then if the system will oscillate of the gain is greater than one.


  Can a type 2 or type 3 compensator be applied on an LDO?


If it is beneficial to do so then yes but don't put the cart before the horses; there are several techniques that can be used to prevent a linear feedback control system from oscillating (becoming unstable) and it's the analysis of the loop gain (or experience or both) that drives the solution.

For the loop gain of a voltage regulator you need to apply a little more attention to compensation methods compared to say techniques used on an AC amplifier. I'm talking about avoidance of "kicks" in the output when the load value (or input voltage) does a step change. This usually means trying to keep the phase margin greater than 45 degrees (generality alert) at all points where the loop gain is significantly high. You do this because you won't want significant ringing or spikes on the output voltage caused by load or input voltage transients. This is mostly achieved by input and output capacitors of course.