1. (1) I. Erlich and U. Bachmann: “Grid code requirements concerning connection and operation of wind turbines in Germany”, Power Engineering Society General Meeting, 2005, IEEE, June 12-16, pp. 2230-2234 (2005)
2. (2) I. Erlich, W. Winter, and A. Dittrich: “Advanced Grid Requirements for the Integration of Wind Turbines into the German Transmission System”, IEEE-PES General Meeting Montreal, panel paper 06GM0837 (2006)
3. (3) T. Burton, D. Sharpe, N. Jenkins, and E. Bossanvi: “Wind Energy Handbook”, John Wiley & Sons, Ltd (2001)
4. (4) S. Mler, M. Deicke, and R. De Doncker: “Adjustable speed generators for wind turbines based on doubly-fed induction machines and 4-quadrant IGBT converters linked to the rotor”, Records of the IEEE IAS Conferernce, Rome, CD (2000)
5. (5) R. Datta and V. T. Ranganathan: “Decoupled control of active and reactive power for a grid-connected doublyfed wound rotor induction machine without position sensors”, Conference Record of the 1999 IEEE Industry Applications Conference, Thirty-Fourth IAS Annual Meeting (Cat. No. 99CH36370), pp. 2623-2628