TY - JOUR

T1 - Design of a medium voltage generator with dc-cascade for high power wind energy conversion systems

AU - Steffen, Jonas

AU - Lengsfeld, Sebastian

AU - Jung, Marco

AU - Ponick, Bernd

AU - Herranz Gracia, Mercedes

AU - Spagnolo, Aristide

AU - Klöpzig, Markus

AU - Schleicher, Klaus

AU - Schäfer, Klaus

N1 - Funding Information: Funding: The authors would like to thank the German Federal Ministry for Economic Affairs and Energy as well as the Project Coordinator Jülich for funding the research project Magnetring III (support code 0324276A) leading to this article. Only the authors are responsible for the content of this publication.

PY - 2021/5/26

Y1 - 2021/5/26

N2 - This paper shows a new concept to generate medium voltage (MV) in wind power application to avoid an additional transformer. Therefore, the generator must be redesigned with additional constraints and a new topology for the power rectifier system by using multiple low voltage (LV) power rectifiers connected in series and parallel to increase the DC output voltage. The combination of parallel and series connection of rectifiers is further introduced as DC-cascade. With the resulting DC-cascade, medium output voltage is achieved with low voltage rectifiers and without a bulky transformer. This approach to form a DC-cascade reduces the effort required to achieve medium DC voltage with a simple rectifier system. In this context, a suitable DC-cascade control was presented and verified with a laboratory test setup. A gearless synchronous generator, which is highly segmented so that each segment can be connected to its own power rectifier, is investigated. Due to the mixed AC and DC voltage given by the DC-cascade structure, it becomes more demanding to the design of the generator insulation, which influences the copper fill factor and the design of the cooling system. A design strategy for the overall generator design is carried out considering the new boundary conditions.

AB - This paper shows a new concept to generate medium voltage (MV) in wind power application to avoid an additional transformer. Therefore, the generator must be redesigned with additional constraints and a new topology for the power rectifier system by using multiple low voltage (LV) power rectifiers connected in series and parallel to increase the DC output voltage. The combination of parallel and series connection of rectifiers is further introduced as DC-cascade. With the resulting DC-cascade, medium output voltage is achieved with low voltage rectifiers and without a bulky transformer. This approach to form a DC-cascade reduces the effort required to achieve medium DC voltage with a simple rectifier system. In this context, a suitable DC-cascade control was presented and verified with a laboratory test setup. A gearless synchronous generator, which is highly segmented so that each segment can be connected to its own power rectifier, is investigated. Due to the mixed AC and DC voltage given by the DC-cascade structure, it becomes more demanding to the design of the generator insulation, which influences the copper fill factor and the design of the cooling system. A design strategy for the overall generator design is carried out considering the new boundary conditions.

KW - DC-cascade

KW - Medium voltage insulation

KW - Permanent magnet synchronous generator (PMSG)

KW - Power rectifier

KW - Wind energy conversion systems (WECS)

UR - http://www.scopus.com/inward/record.url?scp=85107737437&partnerID=8YFLogxK

U2 - 10.3390/en14113106

DO - 10.3390/en14113106

M3 - Article

AN - SCOPUS:85107737437

VL - 14

JO - ENERGIES

JF - ENERGIES

SN - 1996-1073

IS - 11

M1 - 3106

ER -