Study On Winding Inter-turn Short Circuit Of Doubly Fed Induction Generator Considering Control Strategy

Under the new situation of global energy development,the demand for green electricity with low carbon,high efficiency and environmental protection has promoted the vigorous development of new energy sources.Due to the rapid development of our country,there is an increasing demand for energy.In recent years,more attention has been paid to the development and utilization of new energy sources.Wind energy is a very important energy type in new energy,it has been rapidly developed in recent years due to technology maturity and policy promotion.Wind power generation technology is an important way to make rational use of wind energy,now,the doubly fed induction generator(DFIG)is recognized as the main wind power generation model.Due to the particularity of the working environment of the generator,it is very meaningful to study its early fault diagnosis such as winding turn-to-turn short circuit fault.At present,the research on inter-turn short circuit of DFIG is mostly carried out with ignoring the control system,it has a regulating effect on the inter-turn short circuit fault,so the result may have some errors.Based on the multi-loop theory,the mathematic model of DFIG under normal condition and inter-turn short circuit of stator winding is established.The mathematic model of the DFIG is encapsulated into the motor module by MATLAB / Simulink simulation platform.Based on the topology diagram of double PWM converter,the mathematic models of grid-side converter and rotor-side converter are deduced in detail.In the Simulink simulation platform,a complete doubly-fed wind power system is formed by the grid,DFIG,dual PWM converter,transformer and control system,in this system,the simulation of the situation of the normal condition ?inter-turn short-circuit ?the unbalanced voltage and the inter-turn short-circuit under unbalance voltage are respectively carried out.Through the simulation of the above cases,the corresponding current waveforms of the stator and rotor are obtained,the corresponding the electromagnetic torque waveforms are obtained,the rotor current and the electromagnetic torque are analyzed by FFT.Through the analysis,the law of the current and the electromagnetic torque are obtained under different conditions,which provides some basis for the diagnosis of the stator inter-turn short circuit.