Reducing the Inductors of Rectifiers Having Two Outputs to Improve Power Density

Abstract

In this paper, a recently reported single-phase rectifier with two outputs (RECTO) is improved to reduce the neutral inductor and the grid inductor, by moving the neutral inductor away from the path of the grid current. The neutral inductor does not carry the grid current any more so the current stress of the neutral inductor can be significantly reduced, and the size of the inductor becomes much smaller. In theory, the current stress can be reduced by at least three times and the size of the inductor can be reduced by nine times. At the same time, the grid inductor can be reduced to achieve the same level of grid-current switching ripples because of the changed operation modes and modulation strategy. Together, the reduced neutral and grid inductors help improve the system power density. It is worth noting that the voltage and current stresses of the switches and the other features of the RECTO, e.g., two dc outputs and unity power factor, are not affected. Comparative experimental results are presented to demonstrate the reduction. If the two load currents are the same then the neutral inductor is only required to handle the switching ripples. This improved RECTO is particularly suitable for applications with two balanced loads without increasing the cost much.