Snubber Circuit for Marine Controlled-Source Electromagnetic Transmitter

Author(s):  
Hongxi Song ◽  
Yijin Zeng ◽  
Wei Zhang
2019 ◽  
Author(s):  
Rui Yang ◽  
Meng Wang ◽  
Gongxiang Wang ◽  
Ming Deng ◽  
Jianen Jing ◽  
...  

Abstract. Marine controlled-source electromagnetic method has more and more applications in ocean resources exploration. Electromagnetic transmitter sends electromagnetic wave to the underground, the receiver located on the seafloor receives the electromagnetic wave which carries the information of the geosphere. And the underground structure is obtained by inversion calculation. Data quality of electromagnetic transmitter and seafloor receivers is the most important part of this method. The quality level of transmitting current directly affects the signal-to-noise ratio (SNR) of the electromagnetic field data, as received by a multi-component electromagnetic receiver from the seabed. Although the transmitting current stability is sufficient under normal circumstances, the SNR of the received signal can change owing to factors such as outside noise. In some emergency cases such as instrument failure or a sudden increase in electromagnetic interference that we are not aware of, the frequency and properties of the transmitting current may change, such as its size and waveform. The traditional current monitoring and data playback tools fail to detect and evaluate the anomalies well and in a timely manner, which introduces considerable errors in the later data processing procedure. Pertaining to these issues, this paper proposes a comprehensive quality evaluation method for the transmitting current. The proposed algorithm, based on the analytic hierarchy process, is first used to analyse five current stability parameters: current frequency, positive amplitudes, negative amplitudes, discrepancy of ideal waveform, and waveform repetition and then to define the harmonic energy and calculate the quality of transmitting current (QTC) index of the final data to assess the quality of the transmitting current comprehensively. The results of a marine experiment performed in 2016 show that the algorithm can identify abnormal current data and quantitatively evaluate the current conditions. Under normal circumstances, the QTC index is within 2 %. However, after the simulation of anomalous mutations of the various attributes, the QTC index synchronized mutations to more than 4 % and some curvilinear features were observed. These results will provide a positive, significant guide for the evaluation and monitoring of transmitting current data in marine experiments.


2019 ◽  
Vol 2019 (17) ◽  
pp. 4325-4330
Author(s):  
Hongxi Song ◽  
Yiming Zhang ◽  
Junxia Gao ◽  
Yu Zhang

2017 ◽  
Vol 15 (1) ◽  
pp. 62-70
Author(s):  
Meng Wang ◽  
Ming Deng ◽  
Xianhu Luo ◽  
Qingxian Zhao ◽  
Kai Chen ◽  
...  

2017 ◽  
Vol 137 ◽  
pp. 138-144 ◽  
Author(s):  
Meng Wang ◽  
Ming Deng ◽  
Zhongliang Wu ◽  
Xianhu Luo ◽  
Jianen Jing ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Haijun Tao ◽  
Guopeng Zhang ◽  
Zheng Zheng

Nowadays, marine electromagnetic method is a geophysical method which can effectively explore natural gas hydrate (NGH) resources. This method acquires seafloor structure and distribution laws of mineral resources by transmitting high-power electromagnetic waves to the seafloor, and its detection depth relies on the intensity of transmitted electromagnetic waves. At present, marine electromagnetic transmitter is not proper for transmission of high-power electromagnetic waves, and therefore, a novel controlled-source circuit of soft switching three-level marine electromagnetic transmitter is proposed in this paper, one step-down winding is added at the secondary side of high-frequency transformer in series connection with a linear inductor, asymmetric phase-shift PWM control is used, and soft switching of controlled-source circuit within the overall power range is realized. A detailed analysis of the operation process and circuit characteristics is given, and finally, a prototype is designed. Experimental results indicate that this circuit is of wide ZVS range and high efficiency, and it meets requirements for deep-sea detection of high-voltage power supply transmitter.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Hongxi Song ◽  
Yiming Zhang ◽  
Yu Zhang

High power marine controlled source electromagnetic transmitters have gained interest with applications in marine geological survey and mineral resources exploration. The direct current to direct current (DC-DC) converter that is typically used in marine transmitters has some issues, as the insulated-gate bipolar transistor (IGBT) tube cannot achieve zero-voltage switching (ZVS). In particular, lagging-leg switching cannot easily achieve ZVS. The conversion efficiency of the heat converter requires improvement. This paper proposes an improved current-doubler rectifier for the marine controlled source electromagnetic transmitter (ICDR-MCSET). Resonant inductance is increased and a blocking capacitor is added to the converter (DC-DC) circuit, where the converter can achieve ZVS in a wide load range. This results in the effective decrease of the heating temperature and the improvement of transformation efficiency. Saber software simulation and a 20 KW electromagnetic transmitter are used to verify the results, which show that the method is feasible and effective.


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