The Research Of PMSM Position Real-Time Fault Diagnosis And Fault Tolerant Control

Resolver has been widely used in the motor control system with its great advantages of high efficiency,high precision and good working environment adaptability.Resolver is a kind of position sensor in PMSM control system,its output signals include the motor's rotor position information.Resolver to digital converter,which can be called RDC,is a device that can transform the resolver's outputs analog signal into digital signal in which contain rotor position.Generally,RDC refers to the dedicated RDC chip,but thanks to the improvement of the performance of digital signal processor,the software based RDC become the research hot point gradually.Software based RDC has flexible algorithm,it can also restrain the position error and has cost advantage.The structure and working principle of resolver and RDC have been introduced in this paper.Besides,the generation method of resolver's excitation signal and the working principle of single factor sine and cosine generator have been discussed.And then,a novel method which is based on waveform transformation is proposed.It can obtain rotor position from resolver output signals.Two auxiliary sine signals are used to extract the quasi-linear signals form output signals which is nonlinear wave.The quasi-linear signals contain rotor position information.Then,rotor positon signal can be obtained after error correction algorithm.Finally,a series of experiment has been carried out to verify the proposed method.Rotor position is one of the key parameters of permanent magnet synchronous motor control system,the precision of rotor position can directly affect the control precision and performance of the system.Generally,the output signal of RDC has been considered totally correct in traditional PMSM control system and directly used as real rotor position.But,some studies show that RDC's output signal is not ideal because of the machining accuracy,installation error and the parameter error of components of signal processing circuit due to temperature drift can make resolver operate in non-ideal status.These facts can affect the position precision obtained from RDC.On the basis of the rotor position signal extraction algorithm,this article also aimed at rotating transformer possible amplitude unbalance and orthogonal incomplete fault online fault detection and compensation strategies.By analyzing its failure causes and the influence to PMSM control system due to signal fault.The expressions of fault signals have been deduced and the fault compensation algorithm is proposed.Then experimental verification is carried out.In the end,in view of the winding short circuit and open circuit which can cause the sensor broken.A position extracting method based on high frequency signal injection is presented in order to make sure motor won't be out of control.This strategy can make sure the PMSM control system operation in safe status,and it has important theoretical research value and engineering application value.