DC-link voltage selection for a multi-MW wind turbine
Journal article, 2014

Purpose – The purpose of this paper is to investigate how the dc-link voltage for the converter of a wind generator should be selected, i.e. to determine the losses in the generator and the converter when using various dc-link voltage levels. Design/methodology/approach – To presents the efficiency evaluation of 5MW wind turbine generating systems, two 5MW surface mounted permanent magnet synchronous generators (PMSG) with medium and low rated voltage is designed. A two-level transistor converter is considered for ac/dc conversion. Three different dc-link voltage levels are used. By using these voltage levels the PMSG is utilized in slightly different ways. Findings – It is found that the system with the lower voltage machine has slightly higher annual energy efficiency compare to the higher voltage system. Furthermore, it is shown that the best choice for the dc-link voltage level is a voltage between the minimum voltage which gives the desired torque and the voltage which gives Maximum Torque Per Ampere. Originality/value – A procedure as well as investigations with quantified results on how to find the highest complete drive system efficiency for a wind turbine application. Based on two given PMSG, the most energy-efficient dc-link voltage has been established.

Iron losses

Permanent magnet machine

Copper losses

Conduction and Switching losses

IGBT module

Annual energy efficiency


Poopak Roshanfekr

Chalmers, Energy and Environment, Electric Power Engineering

Torbjörn Thiringer

Chalmers, Energy and Environment, Electric Power Engineering

Sonja Lundmark

Chalmers, Energy and Environment, Electric Power Engineering

Mikael C D Alatalo

Chalmers, Energy and Environment, Electric Power Engineering

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

0332-1649 (ISSN)

Vol. 33 1722 - 1740

Areas of Advance


Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering