Surging on a centrifugal compressor is the result not sufficent flow rate through your machine. The operating curve for the compressor will show the minimum operating line commonly also called the surge line.
Surge is stopped by increasing the flow through the machine.
Ayden, basically what happens and this would be true of any rotary compressor, not just centrifugal, is that the compressor is creating pressure on one side of the impeller by forcing a fluid through a converging section (opposite of a nozzle). As new fluid enters the compressor the impeller "pushes" it downstream and that fluid then pushes on the stuff that entered just before it, and that fluid pushes on the fluid in front of it, etc, etc. This takes the lower pressure fluid that enters and creates higher pressure downstream. If the flow decreases to the surge line, there isn't enough fluid to keep pushing on the stuff downstream. Since the stuff downstream is at a higher pressure than the fluid entering AND there isn't enough fluid to maintain the pressure, the flow reverses and you have surge.
It's a funny way of putting that thing. Had you not covered this so nicely, the above link would have surged you
.
Believe it or not : Eratosthenes, a 3rd century BC true philologist, calculated circumference of earth with the help of a stick and it's shadow. The error was just 4% to the present day calcuated value.