基于PL-EPLL的未知时变窄带噪声有源控制方法

针对船舶动力机械装置未知时变窄带噪声的有源控制问题，基于锁相环信号跟踪生成原理，通过在锁相环中引入次级通道执行机构，推导了新的未知时变窄带噪声有源控制方法.首先，通过EPLL（Enhanced Phase Locked Loop）环节中引入次级通道，形成基于EPLL的未知时变窄带噪声有源控制方法；其次，通过近似分析得到其等效线性差分方程，研究了窄带噪声信号幅值和次级通道特性对算法收敛性能的影响；再次，通过引入幅值归一化和次级通道归一化改进措施，提出了基于Pseudolinear（PL）-EPLL的窄带噪声控制方法.相比原方法，改进算法幅值、频率/相位收敛方程的收敛特性与窄带噪声信号幅值和次级通道特性无关，对不同强度分量的多频窄带噪声控制，具有较为一致的收敛速度.最后，通过仿真分析，验证所提出方法的有效性.

PL-EPLL Based Active Control Algorithm for Unknown and Time-Varying Narrowband Noise

To tackle the problem of active cancellation of unknown and time-varying narrowband signal caused by the ship power engineering equipment,an active noise control algorithm for suppressing unknown and time-varying narrowband noise is proposed based on the concept of signal tracking and generation in the phase locked loop (PLL).Firstly,with the introduction of secondary path in the enhanced phase locked loop (EPLL),an active algorithm is developed;secondly,with the approximation analysis,the differential equation of the EPLL-based algorithm is carried out to derive its performance relationship with the input signal amplitude and the secondary path.With normalizing of amplitude and secondary path,an improved pseudolinear (PL)-EPLL based active noise algorithm is derived.Compared to the EPLL-based algorithm,the convergence performance of the estimated amplitude,frequency/phase equation is independent with the amplitude of unknown narrowband signal and secondary path.Besides,the convergence performance is consistent when the noise source is composed of multi-frequency sinusoidal with different signal noise ratio.Finally,simulations conducted validate the effectiveness of the proposed PL-EPLL based active noise control.