The Research Of PMSM Rotor Position Estimating With Online Fault Diagnosis And Fault Tolerant Control

In recent years, the study of using all-digital resolver-to-digital converter (RDC) to obtain PMSM’s rotor position has generally became one of the hotspots in domestic and overseas. This paper mainly focus on integrated online diagnostics with fault tolerant control of all-digital resolver-to-digital converter, and position sensorless control of PMSM based on differential-algebraic estimator. The research will undoubtedly have a significant theoretical and practical value to realize the high efficiency, safe and reliable operation of the electric vehicles PMSM drive system.Firstly, this paper sketchs the fundamental principle of the resolver, then introduces the generation principle of the resolver’s digital excitation signal. Presenting the expression and structure diagram of the single multiplier cosine generator, and indicating the technic advantages using frequency shift demodulation algorithm to realize rotor position demodulation. At last, we purpose the strategy of dual synchronous decoupling phase-locked loop to obtain the motor’s rotor position and speed. The porposed strategy based on DSP of all-digital resolver-to-digital converter obtaining PMSM rotor position is verified by computer simulation.Afterwards, against the fault of the amplitude imbalance and orthogonal incomplete which the resolver may suffer, we analyze the reasons for its failure and the impact on PMSM drive system. Diagnosing fault by extracting the characteristics component of the stator current and then redesigning adaptive fault-tolerant controller to obtain the rotor position deviation so as to compensate it. It can acquire accurate rotor position. The effectiveness of the strategy has been verified by computer simulation.Finally, considering the signal failure or short break of the rotor position sensor, we suggest the algorithm based on differential algebraic estimation method by using stator current and voltage and their first-order numerical differentiation. Architecturing a surface mounted PMSM vector control system based on differential algebraic estimation method. Computer simulation indicates that the proposed method based on differential algebra estimator can get the accurate PMSM rotor position and speed in widespeed range.