1. Introduction
Nowadays, renewable sources are becoming more and more easy to access. Since different renewable sources have different output characteristic, interface converters are usually necessary. It has been shown that using a dc bus to connect different sources has simpler structure and may achieve higher efficiency than using an ac bus. Fig. 1 shows an application of using dc bus in future residential home to integrate solar, wind energy and energy storage [1]. The sources and loads are tied to the dc bus through interface converters. The total dc system is connected to the utility grid through a bidirectional ac/dc converter [2]. In this configuration, only the net-energy need to be processed.
A DC-based nano-grid system in a future home.