Frequency conversion technology is an important energy-saving technology. Most of energy-saving equipments’ speed is not constant and frequency is low. In order to provide power for the energy-saving equipment, a new AC/AC direct conversion power-supply technology is introduced. The main controller is FPGA, which programmable language is VHDL, in this system. The output high-frequency signal from FPGA is driven by drive circuit. Then the output of drive circuit is taken as control signal of MOSFET that is between grid and load. So load gets the voltage with low frequency because power has been plugged by MOSFET periodically. Meanwhile, load gets the low voltage because the switch’s signal is chopped during the time that power has not been plugged. The topology is modeled and simulated in MATLAB. The simulation results prove the technology is correct. The experiment waveform at 7.14 Hz and 2.63 Hz prove that the technology is feasible.