Z-Source Topology for the Entire Circuit Spectrum of Power Conversion

Michigan State University, East Lansing MI

Investigators

Abstract

Today's power conversion circuits are based on the two conventional topologies: voltage-source and current-source, a "two-leg" structure supporting all existing power conversion circuits. The conventional voltage-source (V-source) and current-source (I-source) converters have their theoretical limitations that prevent economical and efficient solutions to many applications. For example, the V-source inverter is a buck converter that cannot produce an output voltage greater than the source voltage. This limitation often requires an additional dc-dc boost converter for many applications such as batteries, photovoltaic, and fuel cells, which makes the power conversion have much lower efficiency, larger size, and higher cost. In this project, we investigate a new type of power conversion circuits, an impedance-source (Z-source) power converter that was proposed two years ago with the intent to overcome the problems associated with the conventional V- and I-source converters. This research project is to extend and apply the Z-source topology to the entire circuit spectrum (categories) of power electronics, including dc-to-ac, ac-to-dc, ac-to-ac, and dc-to-dc power conversion and to develop their control theory. With the successful extension and application of the Z-source concept to all power conversion categories, a "third leg" will be established. This "third leg" will change the entire spectrum of power electronics circuits and provide a third option to optimize performance, maximize efficiency, and minimize cost and size.