Potential Applications and Impact of Most-Recent Silicon Carbide Power Electronics in Wind Turbine Systems

Abstract

Power electronics is an enabling technology found in most renewable energy generation systems. In a wind turbine system, it plays an important role in system integration, power quality, and reliability control. Moreover, the fast growth of wind energy poses the increasing need for high-power, low-loss, and fast-switching power electronic devices in order to reduce the system complexity and cost, and improve reliability and compactness. Among the technologies addressing this need, silicon carbide (SiC) power electronics as the most-recent technology stands out because of its superior voltage blocking capabilities and fast switching speeds. As the research samples of SiC power switches become available, it is possible to discuss the design of a wind turbine system using SiC devices and estimate its performance based on the characteristics of practical devices. Therefore, considering the high-power density and high voltage capability of SiC power devices and the recent trend on wind turbine converters, this chapter focuses on the studies of the application of SiC power devices in a full-scale wind turbine converter. First, the characteristics of the most recent devices are obtained through tests. Then, wind turbine system modeling including models for the major electrical components such as generator, power converter, etc., is discussed in detail. Next, the potential benefits from the use of SiC devices in a wind turbine system are explored by a comparison study of the SiC converter and its Si counterpart. Results are presented and analyzed at different wind speeds, temperatures, and switching frequencies. The conclusions drawn from these studies verify that the application of SiC converters in wind turbine systems can improve the wind system power conversion efficiency and reduce system size and cost due to the low-loss, high-frequency, and high-temperature properties of SiC devices even for one-for-one replacement for Si devices. It is also pointed out that the application of SiC devices may enable medium converter technology for wind turbine applications when such devices become available. In this way, substantial improvement can be achieved. The chapter is organized as follows: Section 4.1 introduces the present status of wind energy and power electronics. It briefly reviews the electrical technologies used in wind turbine systems such as generator, power converter technology, and power electronics suitable for wind turbine applications. It also summarizes the future trends on wind turbine systems. Section 4.2 focuses on studies of the application of SiC power devices in a full-scale wind turbine converter, including discussions on the present SiC device characteristics, system modeling, simulations of two wind turbine systems with the same components expected for the power converters (One is with SiC power converter, and the other is with a Si power converter). Section 4.3 draws the conclusions and discusses the future work.