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.