Research on DC Network Connection with a Novel Wind Power Generator System

Project Description

Wind power technology, as the most competitive renewable energy technology, is quickly developing. The wind turbine size is growing and the grid penetration of wind power is increasing rapidly. Recently, the developments on wind power technology pay more attentions on reliability, and the gearbox driving train is a main concern. Therefore, direct drive system without a gearbox is attractive. Permanent magnet generators (PMG) is an interesting choice for a direct drive wind turbine, however, permanent magnets (PM) could increase the cost and installation difficulties, and PM characteristics, consequently the generator performance, may be affected under severe conditions. However, a Switched Reluctance Generator (SRG), having the features of robustness, fault tolerance and no need for PMs, could be a promising wind power generator.

The research project will investigate a new wind power system, which has a direct drive low speed SRG (DL-SRG) and a DC network connecting the DL-SRGs. The DL-SRG will be designed with an optimization approach, the project partners’ previous experiences on Switched Reluctance (SR) machines, wind power PMGs, including the stator interior permanent magnet generator (SIPMG), will be fully used to exploit the robustness and fault tolerance features of SR machines for the new wind power conversion system. A power electronic system will be developed for the DL-SRG, new types of circuit topologies and control strategies will be studied. Furthermore, a DC network for connecting the DL-SRGs in a wind farm will be investigated in order to establish the highly efficient and reliable wind power plant. The work will be conducted in cooperation with industrial collaborators who will provide support with valuable practical experiences and experimental prototype development.

Project Objectives

The project will investigate a new type of wind power plant which has a direct drive, low speed Switched Reluctance Generator (DL-SRG) and a DC network configuration. The main objectives are:

  • Develop a DL-SRG, study its characteristics and perform a design optimization for various power levels
  • Investigate DL-SRG’s performance as a wind power generator, in both steady state operation and system dynamics
  • Evaluate the DL-SRG in comparison with other types of direct drive generators, including permanent magnet generators and electrically excited generators
  • Study the power electronic switching circuit configurations and control strategy
  • Investigate a DC network of wind farm configuration for connecting the DL-SRGs
  • Derive the operation and control strategies for the new type of wind farm based on DL-SRGs and the DC grid
  • Establish the overall model of wind power conversion systems, perform simulation study
  • Evaluate the overall costs and performance of the system.

Main Results

The main obtained results of the project are as follows:

  • Design and Optimization of DL-SRG
  • The static and dynamic model of DL-SRG and performance analysis of DL-SRG
  • Power electronic driving system for DL-SRG and control method for torque ripple reduction
  • DC network configuration and operation for a wind farm based on DL-SRGs
  • Control strategies for a wind farm based on DL-SRG and a DC network configuration.


Journal Papers
Conference Papers


For overall information of the project, please contact the project leader:

Professor Zhe Chen
Department of Energy Technology
Pontoppidanstraede 101, room 63
Tel.: +45 9940 9255

General Information

Project Period

April 2011 - March 2015

Project Funding

Danish Agency for Science, Technology and Innovation


Project Number

DSF 10-094560

Project Leader

Professor Zhe Chen, Aalborg University, Denmark

Project Leading Institute

Department of Energy Technology, Aalborg University, Denmark

Collaboration Partner

KK Wind Solutions, Denmark

China University of Mining and Technology (CUMT), China

Xuzhou Sanyuan Mechanical & Electrical equipment manufacturing Ltd. China