Aimed at the poor behavior of the dynamic characteristics and the anti-jamming ability of the three-phase PWM converter under traditional PI control, the steady analysis of the three-phase PWM converter under PI control and the influence on the system properties of the PI parameters are conducted employing the root locus. On this basis, a smart PI control method combining the single-neurons and expert system has been applied to the outer-voltage-loop control. The parameters of the outer-voltage-loop controller are regulated online to improve the behavior of the system. Simulations and experimental results verify that the proposed strategy has quick response and small overshoot when the same load changes, the dynamic performance shows excellent index and strong robustness, and the calculation is simple.