[en] Based on the experimental physics and industrial control system (EPICS), a servo power controller is designed to be inserted into the existing power supply for testing its function of measurement and control in real time. The power supply controller uses dead time modulation (DTM) technology to adjust the output current by tracking the external control signal. Zero current switching (ZCS) can work under DTM, thus the switching loss can be reduced and the power efficiency can be greatly improved under high frequencies. In this paper, the principle of the power supply and its controller are introduced, and the DTM method is studied and verified by Matlab simulation and experiment for developing control technology of Tokamak power supplier. (authors)