Dc-Ac Essay

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Pseudo DC link based multi-stage inverter topology is proposed in [26], shown in fig.6, in which DC link is replaced with a pseudo-DC link shown in fig.3(b). As dc link is eliminated in this topology leads to lesser cost, size and volume compared to previous topologies and almost same reliability compared to the previous topology. However, this topology is suffering from poor power decoupling and more harmonic content compared to previous topologies. Common remarks on DC–AC–DC–AC Topologies: Topologies discussed from fig.4-6 have a high-frequency dc-ac inverter at the input side, which converts input dc into high-frequency AC. This high-frequency AC voltage level will be increased using HFT and then converted into dc by using a bridge …show more content…

This type of power conversion scheme generally preferred in most of the PV systems, called Two-Stage Power Conversion Systems (TSPCS)[28-29]. To enhance the design flexibility and power conversion ratio as well as energy harvesting capabilities, the dedicated dc-dc power converter must be placed between PV module and inverter as shown in Fig.2. The main difference between dc-ac-dc-ac and dc-dc-ac power conversion scheme is, the isolated converter is employed in the first method whereas non-isolated dc-dc converter is employed in the second method. Boost, Buck-Boost, SEPIC and Cuk converters are widely preferred for developing this TSPCSs. A simple TSPCS based on dc-dc boost converter fed Half Bridge Inverter (HBI) and Full Bridge Inverter (FBI) is shown in Fig.8 [28] and Fig.9 [29] respectively. They are treated as a conventional two-stage solutions for solar PV applications. In the case of half-bridge topology, dc link is established through the two equal capacitors. These two capacitors act as a three-terminal dc supply to the half-bridge inverter, which converts dc to ac power. Which is then, processed through the filter before feeding to load. In this case, only half of the boost converter voltage is converted into ac. However, in the case of FBI based TSPCS, the full output voltage of boost converter is converted into ac. This means that more output

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