基于EKF的虚拟磁链预测模型及其逆变器控制

Virtual flux prediction model based on EKF and its inverter control

虚拟磁链具有计算简单,易于数字化操作的优点,在交流检测应用中备受关注。但受其本身计算的缺点,对电网电压进行积分时引起的直流偏置与积分饱和现象,严重影响空间矢量定向的精确性。同时无论如何简化控制环节计算延时与检测误差在所难免,导致控制时刻电压并非检测时刻电压,对控制效果有一定影响。该控制方案在检测电压信号的过程中加入虚拟磁链技术,设计了虚拟磁链观测器取代锁相环技术,有效的消除了积分时引起的直流偏置与积分饱和现象。同时推出利用卡尔曼滤波的优秀跟踪预测特性拟合采样电压的虚拟磁链优化算法。仿真实验表明优化算法可以有效的减小谐波畸变,减少系统单周期控制时间。对观测器与算法的仿真研究,表明优化算法的观测器能消除积分饱和现象,消除直流分量对精确定向的影响,消除控制环的延时对系统输出造成的影响,提高系统控制精度和稳定性。

Virtual flux has the advantages of simple calculation and easy to digital operation,which has attracted much attention in the application of alternating measurement. But due to the defect of the calculation,the direct-current bias and the integrator saturation phenomenon caused by the integration of the grid voltage are seriously affecting the space vector orientation. In the process of the voltage measurement,the control method is added to the virtual flux technology. A virtual flux observer is designed,which is used to replace the traditional Phrase-Lock technology. The direct-current bias and the initial integration error are effectively eliminated. Besides,the virtual flux optimization algorithm is derived,and the extended Kalman filtering in imitation system is used to imitate the sampling voltage. The method can effectively reduce the harmonic distortion and the time of single cycle control. The simulation of the observer and the algorithmic demonstration show that the observer optimized by algorithmic can eliminate the phenomenon of integral saturation,and the influence of direct-current bias on the precision orientation,and improve the dynamic performance and control precision of the system.