Cascaded H-Bridge Multilevel PV Topology for Alleviation of Per-Phase Power Imbalances and Reduction of Second Harmonic Voltage Ripple

Christopher D. Townsend, Yifan Yu, Georgios Konstantinou, Vassilios G. Agelidis

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)

Abstract

The cascaded H-bridge (CHB) topology is ideal for implementing large-scale converters for photovoltaic (PV) applications. The improved quality of output voltage waveforms, high efficiency due to transformer-less connection, and ability to employ multiple instances of a maximum power point tracking (MPPT) algorithm are just some advantages. An important disadvantage is the required over-rating to ensure balanced three-phase currents at times of unequal PV generation. Unequal generation occurs due to shading, temperature inhomogeneity, faulty H-bridges, etc. Capacitor voltage balancing under such conditions requires zero-sequence voltage injection which increases the required number of series connected H-bridges. However, leakage current and safety requirements often dictate a need for isolation between PV arrays and the cascaded converter. Therefore, this paper proposes a converter topology that avoids the cost of extra series connected H-bridges by extending the function of dc-dc converters that provide isolation. Second harmonic power oscillations seen in typical cascaded topologies can also be eliminated or reduced through use of the proposed topology. Simulation and experimental results are presented that confirm correct operation of the proposed approach.

Original languageEnglish
Article number7317810
Pages (from-to)5574-5586
Number of pages13
JournalIEEE Transactions on Power Electronics
Volume31
Issue number8
DOIs
Publication statusPublished - 1 Aug 2016
Externally publishedYes

Fingerprint

Dive into the research topics of 'Cascaded H-Bridge Multilevel PV Topology for Alleviation of Per-Phase Power Imbalances and Reduction of Second Harmonic Voltage Ripple'. Together they form a unique fingerprint.

Cite this