By using the solar cell as an assistant power source, the direct power supply to the electric equipments loaded together by the AC power is achieved without storing battery and input into the power grid. After DC/DC boost, the photovoltaic output from the solar cells is connected with the output ends of the rectifier bridge, while tracking the AC power variation to maintain a definite output power under a certain photovoltaic condition. Moreover, a DCDCAC inverter is designed to acquire the AC output consistent with AC power in frequency and phase. It output is connected to the electric equipment but separated from the AC power grid by the unidirectional controlling circuit to only load the equipment without inversely flow into the power grid. Thus the high cost of electricity storage, or power transportation, land occupying, maintenance as well as technical limitations of grid connection.