A Frequency Independent Technique to Estimate Harmonics and Interharmonics in Shipboard Microgrids

Abstract

Modern maritime microgrid systems are witnessing a revolutionary advancement by integrating more renewable energy sources and energy storage systems. The integration of these sophisticated systems is achieved, however, through the power electronics converters that cause severe harmonic contamination. This problem becomes more serious when some of these harmonics that are non-integer multiples of the fundamental (inter-harmonics) exist concurrently with both system frequency drifts and large-power transients, which is a commune issue in maritime microgrid systems such as shipboard microgrids. Hence, the performance of the widely signal processing algorithms applied in the measurement and communication systems such as the smart meters and power quality analyzers tends to worsen. To address this problem this paper proposes an effective method based on the eigenvalue solution to estimate the harmonics and inter-harmonics of modern maritime microgrid systems effectively. This method, which is a system frequency independent technique can work effectively even under large frequency drifts with short window width. The proposed method is evaluated under MATLAB software, and then the experimental validation is carried out via analyzing the electrical power system current of a bulk carrier ship.

An Edge Computing Application of Fundamental Frequency Extraction for Ocean Currents and Waves

“…Figure 1 a shows the classic feature extraction execution scheme [ 6 , 9 , 10 , 12 , 13 , 14 , 15 , 16 , 17 , 20 ]. It is a straightforward procedure.…”

“…There are multiple approaches in the literature to determining the fundamental frequency of a signal. Most solutions are based on the use of the Fast Fourier Transform (FFT) [ 9 , 10 ], Wavelet Transform [ 11 ], Hilbert Transform [ 12 ], least squares optimization, a Kalman filter [ 13 , 14 ] and/or Finite Impulse Response(FIR) filter [ 15 ]. Alternatively, the literature also presents related works that employ specific strategies.…”

Integer Arithmetic Algorithm for Fundamental Frequency Identification of Oceanic Currents

“…Given a signal sampled in time, by applying this algorithm, it is possible to determine the involved frequency tones and their power spectral densities (PSD) [ 8 ]. Similarly, and based on the least squares algorithm, the authors in [ 9 ] estimated the harmonics and interharmonics for intelligent offshore microgrid (SMG) systems. The FFT usage and its window adaptation is the core of the approach.…”

New Horizons for Microgrids: From Rural Electrification to Space Applications

“…The authors show that standard power quality measurement methods are not suitable in SMG applications and that current power quality rules by ship classification societies are insufficient to ensure ship safety. In [42], Terriche et al proposed a method based on virtual exponentials inside the least-square approach to estimate the harmonics and interharmonics of modern maritime microgrids systems. This method is proposed as an improvement over the generalized pencil-of-function method.…”