Modular double‐cascade converter for high‐power medium‐voltage drives. Issue 9 (1st September 2015)

• Record Type: Journal Article
• Authors: Sankala, Arto; Korhonen, Juhamatti; Ström, Juha‐Pekka; Luukko, Julius; Silventoinen, Pertti; Komulainen, Risto; Sarén, Hannu; Södö, Nicklas; Isaksson, Dan
• Is Part Of: IET power electronics. Volume 8:Issue 9(2015)
• Page Start: 1661
• Page End: 1669
• Publication Date: 2015-09-01
• Subjects: AC‐AC power convertors -- power grids -- motor drives -- electric generators -- bridge circuits -- transformer windings; power 76 kW -- voltage 400 V -- power 1.1 MW -- voltage 3.3 kV -- submodule energy sharing capability -- transformation ratio -- medium frequency multiwinding transformer -- power module isolation -- cascaded H‐bridge -- MDC -- grid interface -- generator drive -- medium voltage motor drive -- modular structure -- multilevel AC‐AC converter topology -- modular double cascade converter; Power electronics -- Periodicals; 621.31705
• DOI: 10.1049/iet-pel.2014.0341
• Languages: English
• ISSNs: 1755-4535

Abstract

Abstract : The modular double‐cascade converter (MDC) is a new multilevel AC/AC converter topology, which has a modular structure. The proposed topology can be used in medium‐voltage motor and generator drives, and in interfacing of grids of different voltages and frequencies. MDC is formed with two sets of cascaded H‐bridges where the isolation of the power modules is carried out with medium‐frequency multiwinding transformers. Although the transformers have a transformation ratio of one, the presented topology can be used to transform the voltage level by using different connections for the input and output H‐bridges. The number of steps of input and output voltages can be varied by connecting the modular units of MDC in series or in parallel. The functionality of the topology is verified by simulations of a seven‐level version for a 3.3 kV, 1.1 MW application and experimental results are shown for a 400 V, 76 kW three‐level inverter. In particular, an inherent submodule energy sharing capability through the transformer is analysed and assessed by simulations and experimental tests.