| The mathematic model and vector control of PMSM is first briefly introduced。And based on this，the paper proposes a vector control method which combineMTPA control and the flux-weaking control for wide-speed-range drive of salientpole permanent magnet synchronous motors. The smooth switch between constanttorque region and constant power region can be simply realized using proposedswitch criterion.A modified rotor flux-linkage observer is firstly designed to solve the problemin position sensorless control of PMSM based on the rotor flux-linkage observermethod, In addition, the influence of inaccurate machine parameters to theobserver in terms of the estimated rotor position accuracy has been analyzed and,consequently, a simple steady-state rotor position error compensation technique hasbeen introduced which, theoretically, makes the steady-state rotor position errorbecome negligible and parameter insensitive. The phase-locked loop(PLL) is usedto estimate the rotor speed to replace the differentiator. Therefore, the highfrequency injection method for IPMSM is used to estimate the speed when thePMSM system operates during the low speed area. Then the system simulation isimplemented and the simulation results validate its validity.In order to realize the safety and reliability of the PMSM system, afault-tolerant controller which used in the speed sensorless control was build basedon the maximum Likelihood voting (MLV) strategy. A smooth switch methodbetween different speed area was suggested to solve the signal transition problemfrom the speed switching. And this algorithm will be introduced to thefault-tolerant controller. The simulation results show that the fault-tolerantcontroller can achieve PMSM vector control system fault-tolerant operation. |
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