The motor of a doublyfed induction machine (DFIM) driven multifunctional flexible power conditioner (FPC) can be treated as a doublyfed induction motor with a large rotating inertia and without mechanical load or a doublyfed induction generator without motor. It can regulate the active and reactive power rapidly to enhance the stability of power system. Based on the analysis of control strategy, a 10 kV·A excitation control system of FPC is developed. The proposed control method is experimentally running. Experimental results show that soft start can be implemented, and active/reactive power can be regulated independently. The excitation control system can be applied to a flywheel type FPC system.