This book aims to serve as a state-of-the-art guide to the sizing, modeling, and reliability of capacitors from an application perspective in power electronics, focusing on both classical and emerging power electronics applications. The topics to be covered are as follows: Basics of different types of capacitors and its functions in power electronic systems; Capacitor sizing in direct current (DC) and alternative current (AC) applications; Reliability of electrolytic capacitors, film capacitors, and ceramic capacitors; Application mission profiled based electro-thermal-lifetime modeling of capacitors; Condition monitoring and protection of capacitors in power electronics applications; Capacitor minimization techniques in power electronic systems; Emerging capacitor technology for power electronics applications; 8 design examples in DC-DC converters, modular multi-level converters, photovoltaic inverters, wind power converters, adjustable-speed-drives, solid-state-transformers, and ultra-low inductive capacitor bank design.