Cost on Reliability and Production Loss for Power Converters in the Doubly Fed Induction Generator to Support Modern Grid Codes

Abstract

As wind farms are normally located in remote areas, many grid codes have been issued. Although the doubly fed induction generator based power converter is able to control the active power and reactive power independently, the effects of providing reactive power on the lifetime of the power converter and the cost of energy of the whole system are seldom evaluated, even though it is an important topic. In this article, the loss models of the doubly fed induction generator system are established at various conditions of the reactive power injection. If the mission profile is taken into account, the lifespan of the power semiconductors, as well as the cost of the reactive power, can be calculated. It is concluded that an over-excited reactive power injection significantly reduces the power converter lifetime, only one-fourth of no reactive power exchange between the doubly fed induction generator and the grid. Besides, if the over-excited reactive power is required all year around, the annual loss of energy can reach 2.74% compared to 2.29% in the case of no reactive power injection. Finally, the reactive power effects on the loss dissipation have been verified in a down-scale doubly fed induction generator test rig.

Keywords:

• reactive power
• doubly fed induction generator
• reliability
• cost of energy

Additional information

Notes on contributors

Dao Zhou

Dao Zhou received his B.Sc. in electrical engineering from Beijing Jiaotong University, Beijing, China, in 2007; his M.Sc. in power electronics from Zhejiang University, Hangzhou, China, in 2010; and his Ph.D. in the Department of Energy Technology, Aalborg University, Denmark, in 2014, where he is currently working as a Postdoc. His research interests include power electronics converters and their reliability in wind power generation systems.

Frede Blaabjerg

Frede Blaabjerg was with ABB-Scandia, Randers, Denmark, from 1987 to 1988. From 1988 to 1992, he was a Ph.D. student with Aalborg University, Aalborg, Denmark. He became an assistant professor in 1992, an associate professor in 1996, and a full professor of power electronics and drives in 1998. His current research interests include power electronics and its applications, such as in wind turbines, photovoltaic systems, reliability, harmonics, and adjustable-speed drives.

Mogens Lau

Mogens Lau received his M.Sc. in electrical engineering from Aalborg University, Aalborg, Denmark, in 1999. He worked as development engineer, project manager, and line manager within power electronics at such leading companies as Siemens, Danfoss, Grundfoss, and Vestas. Currently he is working with Siemens Wind Power A/S in Brande, Denmark.

Michael Tonnes

Michael Tonnes received the M.Sc. EE from Aalborg University, Denmark, in 1987 and his Ph.D. from the Institute of Energy Technology in 1990. He was employed by Danfoss in 1987 to perform Ph.D. work within auto-tuning and automatic control of non-linear electrical machines and worked within the technology area of motor controls. He worked at Danfoss (USA) with high-power drives from 1996–1998 and held various management positions within electronic businesses. At present he is a senior director of R&D at Danfoss Silicon Power GmbH, with his base in Flensburg, Germany. He is the author and co-author of a number of articles within auto-tuning, motor controls, and power electronics in general and holds several patents within the fields of motor controls and power electronics.