DFIG-Based WECS With Partial-Scale Converter: Efficiency, Cost, and Volume Comparison of SiC-Based and IGBT-Based Converter Solution

Abstract

The green goals imposed by many countries and the increasing application of renewable energy systems are bringing power electronics to the center of attention. Of particular interest are the wide band-gap devices, as they offer important benefits when considering the efficiency increase and volume reduction. Consequently, they can be viably adopted in renewable energy sources. In this paper, a 2 MW Doubly Fed Induction Generator (DFIG) based Wind Energy Conversion System (WECS) with a bidirectional partial-scale frequency converter composed of two back-to-back converters is considered. The main contribution of the paper is a result of comprehensive comparisons conducted for the two systems: DFIG WECS based on a Si-IGBT converter and DFIG WECS based on a SiC-MOSFET converter in terms of efficiency, volume, and cost. The performed comparison is also a fair comparison, being the selected modules are of the same power ratings. In this way, the previously unspecified but valuable decision-making process regarding the selection of power electronic modules suitable for DFIGs is facilitated. The thermal analysis has been implemented in PLECS, together with the converter control. The realistic libraries obtained from the manufacturers have been included for different power modules. The findings highlight the advantages of employing the Silicon Carbide-based converter in terms of minimizing the size and cost of passive components. They also offer insights on what is needed in order to make the Silicon Carbide solution the absolute best candidate.

Keywords

• SiC devices
• Si devices
• wind energy converters
• efficiency comparison
• doubly-fed induction generator (DFIG)
• wind energy conversion system (WECS)