Capacitor Lifetime Extension of Interleaved DC-DC Converters for Multistring PV Systems

Interleaved dc-dc converters are being vastly applied for a wide range of applications. Inherent power sharing between the power modules and reduction of the output waveforms ripple are the main advantages of these power systems. However, in some cases, such as the multistring photovoltaic converters, each power module manages different power, leading to an unbalanced operation of the interleaved converters. In this case, the harmonic response of the conventional interleaving operation is degraded. This fact affects directly the expected lifetime of the dc-link capacitor of the power converter, which is one critical components of the system. In this article, a variable-angle phase displacement angle is proposed in order to mitigate this problem, achieving an extension of the converter lifetime.