Small Signal Model Averaging of Bi-Directional Converter

Abstract

We consider the problem of modeling a bi-directional AC/DC converter using a small signal approach coupled with cycle averaging to simplify the model for use in digitized control. Small power sources (≤ 1000W) tend to have more abrupt transient power flow due to the associated characteristic low inertia. This is prevalent in small wind turbine systems. In an effort to reduce the complexity of system control under fast power transients, we develop an averaged model which allows for more advanced controller design while keeping computations reasonable low. This effort is intended to complement related work in distributed generation power flow measurement and control suitable for emerging smart-grid and micro-grid systems. We also utilize a more accurate inductor model incorporating resistive effects for the converter power coupling device. Simulation results are provided demonstrating the capability of the model.