针对传统反电势滑模观测器抖振造成的永磁同步电机转子位置检测、转速估算不准确问题,在传统初级反电势滑模观测基础上,提出一种新型反电势双级观测器.通过构造反电势状态观测方程,滤除初级滑模观测器输出反电势高频纹波分量,以获得更为平滑与准确的反电势最优值,采用Lyapunov稳定性理论证明收敛性.同时,考虑观测器增益系数以及低通截止频率的给定,根据实时转速反馈选取观测系数,使得观测系数跟随转速变化获取最优观测值,设计变截止频率降低处理器对低通滤波器相位补偿的计算.对比仿真和实验结果验证了改进双级观测器算法的有效性和实用性.
Since position detection and speed estimation of permanent magnet synchronous rotor based on traditional back electromotive force(EMF)sliding mode observer are not accurate because of chattering,a new kind of doublestage back EMF observer is proposed based on traditional primary sliding mode observation.In order to obtain the more smooth and accurate back EMF optimal value,the state observation equation of back EMF is constructed to filter out the high frequency ripple component outputted from primary observer,and Lyapunov stability theory is used to prove the convergence.Meanwhile,the given of observer gain coefficient and low pass cutoff frequency are considered.The observation coefficient is selected according to real-time speed feedback,and this makes it follow the speed change to get the optimal observation.Variable cutoff frequency is designed to reduce phase compensation calculation of low pass filter by processor.Contrast simulation and experiment results verify improved double-stage observer algorithm is effective and practical.