In order to improve measuring accuracy of the direct current transformer,we studied a type of AC voltage-stabi-lized power supply system that adjusts the output voltage of the incentive power according to the size of the sampling elec-tric current.This system took the TMS320LF240DSP as the core,completed the high accuracy direct current transformer sec-ondary incentive power supply's design using the DSP technology and stepper motor control technology,simultaneously real-ized non-linear compensation of the second excitation power using the small signal direct current sensor and A/D switching circuit.The experimental results show that the system stability of the output AC voltage amplitude up to0.5%,which fully meets the actual use requirements of DC transducer.