Capacitive DC links in power electronic systems-reliability and circuit design

Capacitive DC links are an important part in voltage source power electronic converters, which contribute to cost, size and failure rate on a considerable scale. With more and more stringent constraints brought by industrial applications, the capacitive DC links encounter reliability aspect challenges. This paper presents a review on the reliability design and improvement of capacitive DC links from three aspects: 1) Quantitative reliability prediction for DC-link capacitors; 2) Reliability-oriented design of passive DC-link capacitor banks; and 3) Advanced active DC links to exceed the limits of passive DC-link capacitors. Key solutions for each aspect are highlighted and discussed with case studies. This review serves to provide a picture of state-of-the-art research on the reliability design and improvement of capacitive DC links, highlight the key milestones in this area, and identify the corresponding challenges and future research directions.