(College of Automation and Electronic Engineering, Qingdao University of Science and Technology, Qingdao266042, China)
Abstract:The paper presents saadaptiveslidingmodeobserveronanonlinearobservermethodintermsofthesensorlesspermanentmagnetsynchronousmotorcontrolproblem.BasedonmathematicalmodelofbrushlessDCmotorandclassicslidingmodevariablestructuretheory,accordingtotheobservedandmeasuredcurrenterrorconstitutestheslidingmodeobservertoestimatetheEMF,comb inedwiththeadaptivecontrol,toestimatetherotorpositionandspeed,givestheadaptivelawofestimateandandprovetheconvergenceoftheobserverbasedonLyapunovstabilitycriterion.TheoreticalanalysisandMATLABsimulationresultsshowthatthepermanentmagnetsynchronousmotorsensorlesscontrolmethodhasastrongrobustnesstoloaddisturbancesandmeasurementnoise.
Keywords:PMSM;Slidingmodeobserver;Sensor-lessvectorcontrol;Robustness
0 Introduction
Permanent magnet synchronous motor (PMSM) is a widely used motor due to its small size, high efficiency, reliable operation and good speed regulation performance. The reliable application of sensorless control technology of PMSM in industrial control relies on high-precision estimation of motor speed and position signals. In order to obtain accurate motor speed and position, it is necessary to accurately obtain the back EMF of the motor. The main strategies proposed at present are: 1. Open-loop estimation based on motor model, 2. High-frequency signal injection method, 3. Speed and position estimation method based on back EMF detection, 4. Model reference adaptive estimation method, and 5. State observer estimation method [1]. Among these, the strategy based on the combination of sliding mode variable structure control and state observation has better accuracy and robustness in motor speed and position estimation. The sliding mode observer method is a closed-loop observer method. It is based on the sliding mode variable structure principle and uses the estimation deviation to design the sliding mode control mechanism, which forces the system state to eventually stabilize on the designed sliding hyperplane, which can improve the accuracy, speed and robustness of system parameter estimation [2].
This paper focuses on uncertain nonlinear systems such as PMSM, and adopts...
An adaptive sliding mode observer with varying parameters is proposed for estimating rotational speed and position. An adaptive law for the variation of back EMF gain is given, and an adaptive estimation method for rotor position is put forward. Simulation and experimental results based on the proposed strategy demonstrate that this method can achieve high-precision online estimation of rotational speed and rotor position, exhibiting high estimation accuracy and fast convergence speed.
2 Mathematical Model of Permanent Magnet Synchronous Motor
For a surface-mounted permanent magnet brushless DC motor, assuming the motor's magnetic circuit is unsaturated, neglecting the effects of eddy currents and hysteresis losses, and considering the motor's magnetic circuit to be linear, its voltage equation in the stationary reference coordinate system is:
