Reliability of DC-link capacitors in power electronic converters

DC-link capacitors are widely used in power electronic converters to balance the instantaneous power difference between the input source and output load and to minimize voltage variation in the DC-link. In some applications, they are also used to provide energy storage. Figure 3.1 shows some typical configurations of power electronic conversion systems with capacitive DC-links. Such configurations cover a wide range of power electronics applications, for example, power factor corrections, wind turbines, photovoltaic systems, motor drives, electric vehicles, and lighting systems. It should be noted that a capacitive DC-link discussed here does not necessarily consist of capacitors only. There could also be some inductive components (e.g., DC choke) in the DC bus in some of the above applications.