This paper presents an easier circuit which not only has high power density and good efficiency but also low total harmonic distortion (THD). This inverter is provided by three groups of buck converter. By means of using pulse-width modulation (PWM), each group of buck converter is able to convert output DC voltage to form an AC output. The angle difference between each group is 120 degree, so three-phase AC voltage can be obtained on the load side. Dual-loop control mechanism is used in three-phase inverter control strategy for improving the transient and stability on the star buck converter. The main reason of using the star buck inverter system is reducing the complication of converter circuit installed after the solar system, so the loss of the converter is reduced to minimum. The current sharing control is also used in this system in order to balance the output power of each converter, increase output power and improve the stability and reliability of the whole three-phase inverter system. Finally, a 1.5 kW three-phase inverter system is constructed. The maximum efficiency of the system is 90% and total harmonic distortion is below 3%.