In this study we propose an analytical method based on orthogonal wavelet transforms for detecting harmonic noise and Electromagnetic Interference (EMI) from power supply systems and equipment in coal mines. The metho...In this study we propose an analytical method based on orthogonal wavelet transforms for detecting harmonic noise and Electromagnetic Interference (EMI) from power supply systems and equipment in coal mines. The method will separate interference from signals through wavelet packet decomposition and then accomplish wavelet packet synthesis towards decomposition results after filtering, to remove harmonic noise and electromagnetic interference. Detailed simulation experiments are presented to study power harmonics and Electrical Fast Transient Burst (EFT/B) interference and to validate the effectiveness of our proposed method. The experimental results show that the proposed method, suitable for mutant and non-stationary signal detection, can accurately analyze harmonic interference and EMI in coal mines, as well as establish EMI source models and perform underground Electromagnetic Compatibility (EMC) prediction analyses.展开更多
For the harmonic signal extraction from chaotic interference, a harmonic signal extraction method is proposed based on synchrosqueezed wavelet transform(SWT). First, the mixed signal of chaotic signal, harmonic signal...For the harmonic signal extraction from chaotic interference, a harmonic signal extraction method is proposed based on synchrosqueezed wavelet transform(SWT). First, the mixed signal of chaotic signal, harmonic signal, and noise is decomposed into a series of intrinsic mode-type functions by synchrosqueezed wavelet transform(SWT) then the instantaneous frequency of intrinsic mode-type functions is analyzed by using of Hilbert transform, and the harmonic extraction is realized. In experiments of harmonic signal extraction, the Duffing and Lorenz chaotic signals are selected as interference signal, and the mixed signal of chaotic signal and harmonic signal is added by Gauss white noises of different intensities.The experimental results show that when the white noise intensity is in a certain range, the extracting harmonic signals measured by the proposed SWT method have higher precision, the harmonic signal extraction effect is obviously superior to the classical empirical mode decomposition method.展开更多
Electromagnet interference troubles are more and more and complex with each pass day along with improvement of large system electronization. This article will analyze the interference problems caused by harmonic waves...Electromagnet interference troubles are more and more and complex with each pass day along with improvement of large system electronization. This article will analyze the interference problems caused by harmonic waves in large system. The generation,characteristic and perniciousness of harmonic waves will be qualitatively analyzed for summarizing practical experience to provide mentality and method for settling the large system electromagnet interference trouble. This article raises the approach and method of harmonic suppression from the root of harmonic generation during ultrashort wave transmission and through actual test and analyzing verification. The effectivity and correctness of the methods adopted are certified by theoretical analysis and experimental verification.展开更多
基金the financial support for our work by the Doctoral Foundation of Ministry of Education of China (No.200802900008)
文摘In this study we propose an analytical method based on orthogonal wavelet transforms for detecting harmonic noise and Electromagnetic Interference (EMI) from power supply systems and equipment in coal mines. The method will separate interference from signals through wavelet packet decomposition and then accomplish wavelet packet synthesis towards decomposition results after filtering, to remove harmonic noise and electromagnetic interference. Detailed simulation experiments are presented to study power harmonics and Electrical Fast Transient Burst (EFT/B) interference and to validate the effectiveness of our proposed method. The experimental results show that the proposed method, suitable for mutant and non-stationary signal detection, can accurately analyze harmonic interference and EMI in coal mines, as well as establish EMI source models and perform underground Electromagnetic Compatibility (EMC) prediction analyses.
基金supported by the National Natural Science Foundation of China(Grant No.61171075)the Natural Science Foundation of Hubei Province,China(Grant No.2015CFB424)+1 种基金the State Key Laboratory Foundation of Satellite Ocean Environment Dynamics,China(Grant No.SOED1405)the Hubei Provincial Key Laboratory Foundation of Metallurgical Industry Process System Science,China(Grant No.Z201303)
文摘For the harmonic signal extraction from chaotic interference, a harmonic signal extraction method is proposed based on synchrosqueezed wavelet transform(SWT). First, the mixed signal of chaotic signal, harmonic signal, and noise is decomposed into a series of intrinsic mode-type functions by synchrosqueezed wavelet transform(SWT) then the instantaneous frequency of intrinsic mode-type functions is analyzed by using of Hilbert transform, and the harmonic extraction is realized. In experiments of harmonic signal extraction, the Duffing and Lorenz chaotic signals are selected as interference signal, and the mixed signal of chaotic signal and harmonic signal is added by Gauss white noises of different intensities.The experimental results show that when the white noise intensity is in a certain range, the extracting harmonic signals measured by the proposed SWT method have higher precision, the harmonic signal extraction effect is obviously superior to the classical empirical mode decomposition method.
文摘Electromagnet interference troubles are more and more and complex with each pass day along with improvement of large system electronization. This article will analyze the interference problems caused by harmonic waves in large system. The generation,characteristic and perniciousness of harmonic waves will be qualitatively analyzed for summarizing practical experience to provide mentality and method for settling the large system electromagnet interference trouble. This article raises the approach and method of harmonic suppression from the root of harmonic generation during ultrashort wave transmission and through actual test and analyzing verification. The effectivity and correctness of the methods adopted are certified by theoretical analysis and experimental verification.