Abstract: As a kind of current source rectifier, SWISS rectifier has lower high-frequency switches and no inrush current. In order to improve the power density, there is a basic trade off between the volume of the DC inductor and current ripple. For some applications, the inductance should be decreased to improve the power density, which results in the discontinuous inductor current at light load. When the SWISS rectifier operates at discontinuous current mode, the output voltage is not constant due to the variable AC mains voltage and then the mains currents are non-sinusoidal. To solve this problem, a new modulation scheme which can obtain constant output voltage and sinusoidal mains currents is proposed in this manuscript. Otherwise, zero current switching is realized, which improves the efficiency at light load. Finally, all the analysis are verified by Simulation.