Multilevel Inverters For FACTS and HVDC

Power Electronics provides indispensable power conversion technology to transform today's transportation and energy systems: from electric power generation to transmission, distribution, utilization and storage into more secure, cleaner and more sustainable, more intelligent, more reliable and more efficient ones. Multilevel converters/inverters have become an enabling and promising power conversion technology for high voltage and high power applications in today's power grids, transportation systems, and industrial motor drives. The multilevel concept was established in the early 1990s when the diode-clamped, the capacitor-clamped (or flying capacitor), and the cascade multilevel inverters were proposed. In this talk, we will focus on our research experience in developing the cascade multilevel inverter topologies and their system configurations for power grid applications such as flexible ac transmission system (FACTS) and high voltage dc (HVDC) transmission. More particularly, we will 1) first review the traditional high power conversion technology and its problems; 2) address the needs to eliminate zig-zag transformers required in the traditional technology; and 3) discuss the technical challenges/limitations of the cascade multilevel inverters and our breakthroughs on how to configure the cascade multilevel inverters for FACTS and HVDC. These research breakthroughs have made the cascade multilevel inverters a viable topology for both FACTS and HVDC. For example, many static synchronous compensators (STATCOMs –a voltage and reactive power control device) based on the cascade multilevel inverter have been installed in power grids around the world. Finally, we will present our multilevel inverter research highlights including our most recent breakthroughs: transformer-less unified power flow controller (UPFC) and HVDC converters. These technologies can 1) increase transmission capacity of existing power lines; 2) reduce the need to construct new transmission lines; 3) improve controllability and flexibility of energy routing over the grid; 4) integrate more renewable energy into the grid; and 5) optimize energy transmission and help reduce transmission congestion.

Speaker: Fang Peng, Michigan State Univ

Room 521