This invention provides a modulation for three-phase AC/DC converter. This modulation can achieve soft switching and thus improve converter efficiency, especially for high-density-driven high frequency operation. In spite of variable switching frequency operation, this modulation has narrow switching frequency variation range, which reduces switching related loss. This modulation can be applied in both inverter mode and rectifier mode, and also can be applied in both non-interleaved operation and two-channel-interleaved operation.