与传统接触式充电方式相比,采用感应式电能传输IPT(inductive power transfer)系统给自主水下航行器AUVs(autonomous underwater vehicles)充电更加方便和安全。为了解决AUV船体中心磁场强和由波浪引起的旋转偏移导致传输功率剧烈波动...与传统接触式充电方式相比,采用感应式电能传输IPT(inductive power transfer)系统给自主水下航行器AUVs(autonomous underwater vehicles)充电更加方便和安全。为了解决AUV船体中心磁场强和由波浪引起的旋转偏移导致传输功率剧烈波动的问题,提出1种具有新型耦合结构的三相IPT系统。耦合器由3个发射线圈和4个反向交替串联的接收线圈组成,该结构有利于抑制中心磁场并提高抗旋转偏移性能。Maxwell仿真结果表明,在船体旋转时,等效互感Meq波动小于2%,同时AUV中心磁场始终保持在较低水平。此外,为简化系统分析,采用1种无源元件解耦的方法对3个发射线圈进行解耦。搭建了1台基于LCC-S补偿拓扑的实验样机来验证系统的可行性,实验结果表明,当AUV旋转时,传输功率为536~595 W,最大波动率为9.91%,系统直-直最高效率为86.28%。展开更多
Accuracy of angle-domain common-image gathers(ADCIGs)is the key to multiwave AVA inversion and migration velocity analysis,and of which Poynting vectors of pure P-and S-wave are the decisive factors in obtaining multi...Accuracy of angle-domain common-image gathers(ADCIGs)is the key to multiwave AVA inversion and migration velocity analysis,and of which Poynting vectors of pure P-and S-wave are the decisive factors in obtaining multi-component seismic data ADCIGs.A Poynting vector can be obtained from conventional velocity-stress elastic wave equations,but it focused on the propagation direction of mixed P-and S-wave fields,and neither on the propagation direction of the P-wave nor the direction of the S-wave.The Poynting vectors of pure P-or pure S-wave can be calculated from first-order velocity-dilatation-rotation equations.This study presents a method of extracting ADCIGs based on first order velocitydilatation-rotation elastic wave equations reverse-time migration algorithm.The method is as follows:calculating the pure P-wave Poynting vector of source and receiver wavefields by multiplication of P-wave particle-velocity vector and dilatation scalar,calculating the pure S-wave Poynting vector by vector multiplying S-wave particle-velocity vector and rotation vector,selecting the Poynting vector at the time of maximum P-wave energy of source wavefield as the propagation direction of incident P-wave,and obtaining the reflected P-wave(or converted S-wave)propagation direction of the receiver wavefield by the Poynting vector at the time of maximum P-(S-)wave energy in each grid point.Then,the P-wave incident angle is computed by the two propagation directions.Thus,the P-and S-wave ADGICs can obtained Numerical tests show that the proposed method can accurately compute the propagation direction and incident angle of the source and receiver wavefields,thereby achieving high-precision extraction of P-and S-wave ADGICs.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities(No.201822011)the National Key R&D Program of China(No.2018YFC1405900)+1 种基金the National Natural Science Foundation of China(Nos.41674118 and 41574105)the National Science and Technology Major Project(No.2016ZX05027002)。
文摘Accuracy of angle-domain common-image gathers(ADCIGs)is the key to multiwave AVA inversion and migration velocity analysis,and of which Poynting vectors of pure P-and S-wave are the decisive factors in obtaining multi-component seismic data ADCIGs.A Poynting vector can be obtained from conventional velocity-stress elastic wave equations,but it focused on the propagation direction of mixed P-and S-wave fields,and neither on the propagation direction of the P-wave nor the direction of the S-wave.The Poynting vectors of pure P-or pure S-wave can be calculated from first-order velocity-dilatation-rotation equations.This study presents a method of extracting ADCIGs based on first order velocitydilatation-rotation elastic wave equations reverse-time migration algorithm.The method is as follows:calculating the pure P-wave Poynting vector of source and receiver wavefields by multiplication of P-wave particle-velocity vector and dilatation scalar,calculating the pure S-wave Poynting vector by vector multiplying S-wave particle-velocity vector and rotation vector,selecting the Poynting vector at the time of maximum P-wave energy of source wavefield as the propagation direction of incident P-wave,and obtaining the reflected P-wave(or converted S-wave)propagation direction of the receiver wavefield by the Poynting vector at the time of maximum P-(S-)wave energy in each grid point.Then,the P-wave incident angle is computed by the two propagation directions.Thus,the P-and S-wave ADGICs can obtained Numerical tests show that the proposed method can accurately compute the propagation direction and incident angle of the source and receiver wavefields,thereby achieving high-precision extraction of P-and S-wave ADGICs.
