An Efficient Single-Sourced Asymmetrical Cascaded Multilevel Inverter With Reduced Leakage Current Suitable for Single-Stage PV Systems
| Autor: | Mohana Sundar Manoharan, Ashraf Ahmed, Joung-Hu Park |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | IEEE Transactions on Energy Conversion. 34:211-220 |
| ISSN: | 1558-0059 0885-8969 |
| DOI: | 10.1109/tec.2018.2874076 |
| Popis: | An isolated single sourced multi-output dc/dc converter with a high-frequency link was proposed before to feed different cells of the Asymmetrical Cascaded H-bridge (ACHB) inverter. One of the fundamental advantages of the ACHB is that the main H-bridge is commutated with fundamental frequency, passing the majority of the inverter power. However, the isolated dc/dc converter needs to be connected to the main voltage source with high-voltage/high-frequency switches, which limits the power capability and the efficiency of the converter. In this paper, a switching pattern based on nearest level modulation method is proposed to command all the power to be transferred through the main H-bridge. Therefore, the power circulates between the auxiliary H-bridges with no need for high-voltage switches. As a result, a single-input single-output auxiliary converter is needed with only 5% of the power rating. This solution reduces cost and size while it improves the efficiency of the converter. Furthermore, the architecture makes the inverter more suitable for high power and high-voltage applications. The inverter switching strategy is based on programmable firing angles. The main dc-link of the grid connected inverter is controlled to achieve maximum power point tracking, while the dc/dc isolated converter is controlled to regulate the auxiliary dc-links. The proposed topology is verified by simulation and experimental results using a 1.5 kW hardware prototype. |
| Databáze: | OpenAIRE |
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