High Density Energy Storage
In many traditional power distribution systems, the roles were well defined for power sources, loads, and distribution networks, and the components were designed according to these roles. With recent advances and interest in renewable energy sources and energy storage, and growing demand for higher system efficiency, reliability, and scalability, there is a need to develop more intelligent power conversion systems with bi-directional power flow and multi-functional capability. In such systems, local areas become "micro-grids," capable of autonomous operation as well as importing or exporting energy to an external grid, providing significant opportunity of improved system operation and reliability, but requiring design for stable operation over a wide range of conditions. For example, electric and hybrid-electric motor drives, supercapacitors, and batteries can all act as energy sources or sinks and can be used for primary purposes such as vehicle propulsion and backup power and for secondary purposes such as system efficiency optimization and bus stability control. We have projects looking at design of very high efficiency, high power density, scalable bi-directional power converters that can be used as intelligent interfaces to optimize operation between renewable energy sources, enegy storage, ac and dc grids, and a wide range of loads. We are also working on collaborative programs that consider interaction between the converters and the power system and overall system stability and efficiency optimization.