A frequency-dividing collaborative control strategy of selective harmonic elimination pulse width modulation (SHEPWM) for three-level neutral point clamped based dual-module grid-tied converters was proposed aiming at the disadvantages of low switching frequency and large current harmonics of medium voltage high power grid-connected converters. Current harmonic performance of dual-module parallel-connected system was effectively improved by restricting output harmonics of each module to zero in low-frequency band, while total output harmonics of the dual-module was controlled to zero in high-frequency band. A frequency adaptive generalized integral (GI) controller was introduced in order to suppress the inherent 5th and 7th harmonics in the grid current caused by the dead-zone of the devices. Parameters of the GI controller were directly designed in discrete domain to avoid the undesired loss of high control precise due to discretization process. The simulation and experimental results verify the effectiveness and superiority of the proposed strategy.