The increasing complexity of the electromagnetic environment poses a threat to the reliability of intelligent connected vehicles. Carrying out performance verification of intelligent connected vehicles in different electromagnetic scenes plays an important role in ensuring the safety of vehicles. A method for constructing electromagnetic scenes in the 10m semi-anechoic chamber is presented in the paper. By constructing the electromagnetic environment collection system, the main technical indicators of the electromagnetic environment collection related to the intelligent connected vehicles are analyzed, and the construction scheme of the electromagnetic environment scene library is studied. Based on the electromagnetic environment simulation system, the effectiveness of the electromagnetic scene reproduction is verified from the two aspects of test result comparison and signal comparison, which provides support for the test and verification of the electromagnetic compatibility performance of the intelligent connected vehicles in the laboratory.

Research on construction method of electromagnetic scene suitable for intelligent connected vehicle

An algorithm for output spectrum analysis of nonlinear system with correlative sources is proposed. First, the output terms of nonlinear system are analyzed based on the power series. Then, the algorithm is proposed. In the proposed method, different terms with the same frequency are picked out and added together by considering different phases, and the amplitudes of the output spectrum are obtained from the summarized results. Two numerical examples are used to verify the proposed algorithm. It is found that the amplitudes of output spectrum vary with different combinations of phases. Finally, the proposed algorithm is applied to control the output spectrum. Results show that the output amplitude of a specific frequency can be suppressed through changing both the amplitudes and the phases of the input signals.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/cje.2020.08.018

An Algorithm for Output Spectrum Analysis of Nonlinear System with Correlative Sources Based on Power Series

To evaluate the occupational safety of a high signal operator exposed to the electric field induced by contact wires with a frequency of 50 Hz and a voltage of 27.5 kV, this study established a model of a high signal operator working in the vicinity of singleand double-track railways. The electric field distribution in the operator’s body and his head were calculated and analyzed during the operation using the finite element method (FEM). The calculated results were compared with the international standard occupational exposure limits formulated by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and action levels (ALs), exposure limit values (ELVs) in Directive 2013/35/EU (EU Directive). In the case of a single-track railway exposure, the maximum electric field strength in the worker’s body, in the scalp layer, and inside the brain are 227 mV/m, 2.76 kV/m, and 0.14 mV/m, respectively. For a double-track railway exposure, the maximum internal electric field strength of the operator is 310 mV/m, which is 37.85% of the occupational exposure basic restriction limit. The maximum electric field strength in the head layers is 3.42 kV/m, which is 34.2% of the occupational exposure reference level and 34.2% of the low ALs. The maximum electric field strength of the brain is 0.19 mV/m, which is 0.19% of the occupational basic restriction limit and 0.135% of the sensory effects ELVs. Results show that the electric field exposure of the high signal operator to contact wires in singleand double-track railways is lower than the occupational exposure limits provided by the ICNIRP and EUDirective standards and is thus regarded as safe for workers.

Safety evaluation for a high signal operator with electric field exposure induced by contact wires

In this review, we review the recent research progress and results of piezoelectric energy harvesters applying mechanical tuning techniques in terms of literature background, methods of mechanical tuning, and practical applications. In the past few decades, piezoelectric energy harvesting techniques and mechanical tuning techniques have received increasing attention and made significant progress. Mechanical-tuning techniques are those that allow the resonant vibration energy harvesters the mechanical resonant frequency values to be adjusted to coincide with the excitation frequency. According to the different tuning methods, this review classifies mechanical-tuning techniques based on magnetic action, different piezoelectric materials, axial load, the variable center of gravity, various stresses, and self-tuning and summarizes the corresponding research results, comparing the differences between the same methods. In addition, the current application of the mechanical-tuning techniques is introduced, and the future development of mechanical tuning techniques is analyzed, facilitating the reader to better understand how mechanical-tuning techniques can improve the output performance of energy harvesters.

Piezoelectric energy harvesting systems using mechanical tuning techniques.

From technology importation to independent innovation, Chinese High speed railway (HSR) has been rapidly developed in the past a few years. However, this technology development mode introduces very complex electromagnetic environment of HSR system, which is based on various equipment with different Electromagnetic compatibility (EMC) design. Consequently, the suppression of electromagnetic disturbance and the electromagnetic protection is becoming an urgent issue for HSR. The characteristics of traction power supply technology, train operation control technology and other core technologies are quite unique in Chinese HSR. In this paper, the EMC and the electromagnetic safety issue of Chinese HSR is discussed, which is derived from technology development mode and core technology characteristics. The limitation of the high speed train's exportation due to the lack of test method for the train's emission is also analyzed. Combining the electromagnetic environment characteristic and the development planning of Chinese HSR, several suggestions in the research of antielectromagnetic interference, electromagnetic protection in the strong electromagnetic field and the whole large system's radiation emission test method are put forward.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/cje.2019.09.002

Yinghong Wen

Papers

Research on Electromagnetic Compatibility of Chinese High Speed Railway System