Analysis And Compensation Strategy Of Position Errors In High Frequency Carrier Signal Injection Based On Sensorless Control System Of PMSM

Permanent magnet synchronous machines(PMSMs)are widely applied due to high torque density,power sensity,and efficiency.However,the vector control strategy is implemented based on high-resolusion rotor position information.In general,this rotor position information can be obtained from mechanical sensors,which may increase system cost and size,and tend to reduce the system reliability.Therefore,various sensorless techniques have been developed.In the low speed region and at standstill,high frequency signal injection is preferred to implement rotor position estimation,which normally injects an extra signal into the machine windings and the phase carrier current response is motor saliency dependent due to the machine geometric saliency.The position dependent carrier response is utilized for estimation the rotor position by a position tracking observer.However,the stator inductance is distorted by magnetic field distortion due to the limitation of motor design and manufacturing or motors operate in magnetic saturation state,thus the estimation of rotor position become more complicated.Meanwhile,the principle of all HF voltage injection methods is to detect the magnetic saliency instead of the mechanical saliency of the PMSMs,At load condition when there is q-axis armature reactance,the magnetic field distribution in PMSM is distorted and hence an average saturated position estimation error.To overcome this problems,some works were done as follows1?In order to analysis the influence of phase harmonic inductance on position estimation,a non-ideal motor model is established firstly.Besides,to implement sensorless control,a novel sensorless strategy is proprosed by injecting square voltage signal into stationary frame.Compared with traditional voltage signal injection method,the proposed method will cause less torque ripple.2 ? A orthogonal phase lock loop using model reference adaptive control technique has been designed.The proposed position observer can suppress the 6th oscillating position errors in the position estimation caused by the 4th phase harmonic inductance.Experimental results is provided to evaluate the proposed self commissioning decoupling method.3?In order to suppress the average position estimation error caused by cross coupling effects,the cross coupling angle are approximately proportional to q-axis can be seen from experimental results,with which the online compensation can be achieved.Finally,to verify the effectiveness of the proposed adaptive compensation strategies,Matlab/simulink was given to conduct the proprosed control strategies.the experimental results confirm the reliability of the proposed method by 1.5kW IPMSM control system.