The Research On Double Fed Wind Power Generating System Based On Matrix Converter

This paper indicated that wind-power generating industry has been an important subject on energy source exploitation and utilizing all over the world. The significance on Chinese economy development of wind-power generating also be introduced in this paper. The method, variable speed and constant frequency (VSCF), has been a major one in nowadays wind-power generating system. VSCF can track the maximal power point of the system and output constant frequency power when wind speed change. Through comparing several ways in VSCF, this paper adopted double fed induction generator (DFIG) wind power generating system.DFIG wind power generating system is a new VSCF system that has been pop researched in the world. In chapter 3, the advantages, working principle, mathematics model in three phase stationary reference frame about DIFG have been introduced. Its working status in sub-synchronous, super-synchronous and synchronous at different wind speed has also been analyzed from the eyes of power flow.In order to realize effective control of DFIG, vector control theory has been adopted. Chapter 4 analyzed the principle of vector control, and changed the mathematics model from three phase stationary (a, b, c) to two phase rotating (d, q) reference frame. After that, adopted stator-flux oriented method to regulate the active power and reactive power respectively. Additional, this chapter also discussed the way of rotor current forward fed back compensating and flux observation. The control diagram of DFIG wind power generating system has been shown in the end of Chapter 4.Matrix Converter (MC), a new kind of AC-AC converter has been used in the system. Chapter 5 gave the advantages of MC and analyzed its working principle, especially introduced the Space Vector Modulation (SVM) of MC, which including space vector representation of input and output variables, selection of switching vectors and computation of vector time intervals and so on.Finally, the simulation results of this system proved the correctness of foregoing theories. The simulator was written in C language and its experimental data have been sent into Matlab to form experimental pictures, which showed a good performance of DFIG wind power generating system. The stator not only could output constant frequency current but also maximize the output power. Active and reactive power could be regulated respectively. The requirement of VSCF control could be well realized in this scheme.