基于对偶观测器的谐波提取方法

提出一种基于对偶观测器的标准正弦信号提取方法.将受到谐波干扰的信号通过一种辅助滤波器得到与谐波频率相关的可测变量;然后利用对偶关系将受干扰信号分解为已知函数和受标准正弦信号驱动的待估项;进而构造观测器估计未知参数,直接对标准正弦信号进行重构.该方法可以将谐波信号表示为关于辅助变量的参数形式,直接建立频率与干扰谐波之间关系,实现标准信号与干扰谐波的分离.由于只需要估计受标准正弦信号驱动的未知参数,很大程度上可以降低计算复杂度.利用李雅普诺夫稳定性理论证明:当不存在有界噪声时,这种观测器可以渐近跟踪标准频率信号;在多源干扰环境下,观测器误差动态满足一致最终有界特性.仿真结果验证了该对偶观测结构的有效性.

Harmonic extraction method based on dual observer

In this paper, a sinusoidal extraction method based on a dual observer is proposed. Passing the disturbed harmonic through an special auxiliary filter, measurable variables related to the harmonic frequency can be obtained. Then the unexpected signal is decomposed into a known function and the required estimation term driven by standard signal. The observer is constructed to estimate the required estimation term, thereby the standard sinusoidal signal can be reconstructed directly. This method can represent the disturbance as a parametric form about auxiliary variable, so as to derive the relationship between frequency and harmonic directly, with which the standard signal and disturbance can be decoupled. Because only the unknown parameter driven by standard sinusoidal signal needs to be estimated, the computational complexity is greatly reduced. According to the Lyapunov stability theory, if the bounded noise is absent, the observer can track the standard signal asymptotically. In the multi-disturbances environment, the uniform ultimately bounded performance of estimation error can be guaranteed by adjusting the parameters. Simulation results demonstrate the effectiveness of the proposed dual observation structure.