The traditional three-dimensional space vector modulation(3D-SVPWM)strategy applied in three-phase four-wire three-level mid-point capacitor converter is complex

and the neutral-point potential balance scheme is not accurate for suppressing the neutral-point potential shift. Especially in the case of unbalanced load condition

the neutral current flows through the neutral-point of the DC-link

when will cause the neutral-point potential offset. To solve this problems a simplified 3D-SVPWM strategy based on three-phase abc coordinate system is presented and a neutral-point potential balance scheme based on the simplified method is proposed. According to the potential shift

the value of potential shift is averagely distributed to the phase with capability of balancing neutral-point potential to make multiple phases balance the neutral-point potential together. The value of time needed to compensate the shifted potential is calculated by the mathematical model

and then acts on the output state of the three-level converter to achieve the goal of balancing the neutral-point potential. Simulation analysis and experimental results show that the optimized modulation strategy has good performance on controlling the neutral-point voltage for three-phase four-wire three-level converter.