A4 Conference proceedings

Discontinuous modulation method for isolating DC-DC converter to mitigate grid-side DC link voltage fluctuation


Publication Details
Authors: Korhonen Juhamatti, Silventoinen Pertti, Giewont William, Isaksson Dan
Publication year: 2018
Language: English
Title of parent publication: 2018 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)
Start page: 467
End page: 472
Number of pages: 6
eISBN: 978-1-5386-4941-1
JUFO-Level of this publication: 1
Open Access: Not an Open Access publication

Abstract

This paper proposes a discontinuous modulation strategy of an isolating
DC-DC converter on the photovoltaic plant side to reduce the grid side
inverter DC link voltage fluctuation. Cascaded H-bridges (CHB) can be
used to connect a photovoltaic plant directly to a medium voltage grid
without a grid frequency transformer, as the topology has an inherent
requirement of having an isolation between the series connected cells.
Cascaded H-bridges has a feature that the DC link voltages of the cells
have a voltage fluctuation at twice the output frequency. This
fluctuation can be reduced by limiting the power towards the capacitor
during intervals when the output power is low. The effect of
discontinuous mode interval length on the photovoltaic side is studied.
The benefits of the proposed method are reduced switching losses at the
isolating DC-DC converter and reduced switching losses at the grid
inverter due to smaller peak voltages of the DC links.


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Last updated on 2019-10-10 at 14:47