A simulation-based comparison of direct and indirect current-sharing methods

Current-sharing (CS) techniques are developed to even out the current stresses among non-identical paralleled power modules. Different applications of them result in different CS methods. For a parallel power module system with O-ring connected configuration, which is widely used to achieve high reliability, there are two kinds of the CS methods: the direct method and the indirect method. In the direct method, the CS function is implemented in the power modules. In the indirect method, the CS function is implemented in the oring-connected protection circuit. Compared with the direct method, the indirect method offers the advantage of requiring no CS interconnections among the power modules, which makes the paralleling of power modules much simpler. Since the indirect method is a newly developed method, not much has been reported regarding its performance. This paper aims to make a simulation-based comparison of the direct and indirect methods. The focus is on the steady-state and dynamic-state characteristics.