Research On A Vector Control Strategy Of The Tooth-standing Wave Brushless Doubly-fed Machine

The vector control strategy of a tooth-standing wave brushless doubly-fed machine(TWBDFM)is studied and designed.In the fields of variable speed constant frequency power generation and speed drive,A TW-BDFM have great potential applications.With the increase of the practical application of the TW-BDFM,the system of the TW-BDFM dynamic response is needed more quick,and various control targets are proposed for the BDFM system.The law of magnetic field distribution of BDFMs with different rotor structures is analyzed and the effects of different loads on the magnetic fields of the TW-BDFM under the power generation are detail studied in the paper.According to the analysis of the flux linkage and torque of the BDFM,the mathematical model and equivalent circuit of the TW-BDFM are established with the reference of the doubly-fed permanent magnet motor equivalent circuit.Different experiments were designed to test and calculate the machine equivalent circuit parameters of the TW-BDFM.Combined with the traditional induction motor vector control,a vector control strategy for the TW-BDFM is proposed and the vector control strategy is applied to the independent power generation system,grid-connected power decoupling control system and the brushless doubly-fed motor drive.The research history and current status of BDFMs and their control systems are reviews,and the research work of foreign and domestic scholars on optimizing the performance of BDFMs and the research process of BDFM control systems are introduced.The problems and research significance of the BDFM and its control system are analyzed.Secondly,the law of air gap magnetic field distribution of BDFMs with different rotor structures is detail analyzed.The air-gap flux is kept stable when the load of the machine is changed,and the control strategy for the TW-BDFM is facilitated.Thirdly,the response of magnetic field is different for different loads,and the composition of the flux linkage and torque of the BDFM are detail analyzed.The electromagnetic in the BDFM is interacted and the BDFM windings are coupling each other,which is lead to the difficult to obtain the equivalent model.Referring to the equivalent circuit of the doubly-fed permanent magnet motor and according to the superposition theorem,the equivalent circuit and mathematical model of the BDFM are redefined and the model of the BDFM is equivalent to the control side equivalent circuit and the power side equivalent circuit.The simulation model of the TW-BDFM is established in Matlab.The feasibility and correctness of the equivalent circuit of TW-BDFM are verified by simulation and experiment.The equivalent circuit proposed in this paper has clear physical meaning and parameters are easy to measure and calculate.Then,a vector control strategy based on the equivalent circuit of the TW-BDFM is proposed in the paper.The vector control strategy is based on the magnetic winding flux linkage and rotor speed transformation and is simulated and experimentally to verify under different working conditions.In order to improve the reliability of the TW-BDFM control system,a control strategy without position sensor based on the power winding frequency closed-loop independent power generation system is introduced and a model-adaptive flux linkage speed observer which is realized the TW-BDFM without position sensor control is proposed in the paper.Finally,the reason of low-frequency oscillation of TW-BDFM based on the coupled equivalent model is analyzed,and the engineering method and improved control strategy for suppressing oscillation are proposed.