基于复系数滑模观测器的永磁同步电机位置估计误差抑制

Position estimation error suppression of PMSM based on complex coefficient sliding mode observer

采用sigmoid函数的传统滑模观测器能够有效抑制滑模抖振,但反电动势的估计值与实际值之间存在幅值和相位偏差。为了抑制估计反电动势相位滞后导致的位置估计误差,首先根据观测器模型,分析了传统滑模观测器的位置估计误差产生机理。其次,利用两相静止坐标系的相位关系在传统滑模观测器中引入复系数电流误差项,构造了一种复系数滑模观测器以消除估计反电动势的相位滞后,从而提高无位置传感器控制系统的位置估计精度。最后,根据李亚普诺夫稳定性理论和观测器状态方程分析了复系数滑模观测器的稳定条件和动态性能。理论分析和实验结果表明:所提出的复系数滑模观测器结构简单、运算量低,能够有效抑制估计反电动势相位滞后的问题,提高转子位置估计精度。

The traditional sliding mode observer based on the sigmoid function can effectively suppress sliding mode chattering,but there are amplitude and phase deviations between the estimated value and the actual value of the back-EMF.In order to suppress the position estimation error caused by the phase lag of estimated back-EMF,firstly,the causes of position estimation error was analyzed according to the traditional sliding mode observer model.Then,a complex coefficient sliding mode observer was construc-ted by introducing the complex coefficient current error term into the traditional sliding mode observer based on the phase relationship of the two-phase stationary coordinate system.The phase lag of estimated back-EMF was to be eliminated,and the position estimation accuracy of sensorless control system was to be improved.Finally,the stability conditions and dynamic performance of the complex coefficient sliding mode observer were analyzed based on Lyapunov stability theory and the observer state equation.Theoret-ical analysis and experimental results demonstrate that the proposed complex coefficient sliding mode ob-server has a simple structure and low computational complexity,which can effectively suppress the phase lag of the estimated back-EMF and improve the accuracy of position estimation.