3 results about "Electromagnetic current" patented technology

This invention discloses a method for obtaining the wide-angle single-station RCS of a medium target based on a compressed sensing algorithm. The steps are as follows: setting a wide-angle uniform incident plane wave illuminating the medium target; defining RWG basis functions and calculating the excitation vector for each incident angle; performing sparsification and compression on the excitation vectors respectively; generating the PMCHWT equations for the target surface and solving to obtain the compressed induced electromagnetic current matrix; recovering the original induced electromagnetic current matrix from each column of the compressed induced electromagnetic current matrix using the OMP algorithm; and calculating the radar cross section of the medium target based on the induced electromagnetic current vectors. This invention can obtain the RCS result at any angle with fewer PMCHWT equation solutions and combined with the OMP recovery algorithm, reducing the solution time for the wide-angle RCS of the medium target while ensuring accuracy.

This invention provides an integrated and accurate simulation method for electromagnetic scattering of partially rotating targets, comprising: modeling and setting system parameters; dividing the target into relatively stationary sub-regions, rotating sub-regions, and linked sub-regions, and establishing a rotationally symmetric equivalent surface to completely enclose the rotating sub-domains; establishing a global coordinate system and a local coordinate system; using a consistent mesh in the global coordinate system as the outer mesh, and independently meshing the local coordinate system as the inner mesh, and defining the inner and outer basis functions accordingly; calculating the self-acting operator, equivalent operator, coefficient solving operator, and interaction operator of the equation to be solved; updating the coordinate system rotation operator between the global and local coordinate systems, establishing and solving the equation to be solved for the partially rotating conductor target at the current moment, and then calculating the far-field scattering field at the current moment from the scattering electromagnetic current coefficient vector; repeating the first two steps until the calculation of the far-field scattering field at different sampling time points throughout the entire rotation cycle is completed. This method has a fast modeling speed.

This application provides a harmonic elimination method and apparatus for modular multilevel converter high-voltage direct current (HVDC) transmission, comprising: constructing a current and voltage measurement matrix based on the topology and electrical parameters of an electromagnetic current transformer, its secondary system, an electromagnetic voltage transformer, and its secondary system in the HVDC transmission system; constructing an HVDC transmission impedance model including current and voltage measurement components based on the main circuit topology of the HVDC transmission system and the current and voltage measurement matrix; analyzing the HVDC transmission impedance model under preset operating conditions to obtain the impedance matrix of the current and voltage measurement components; and determining the resonant frequency of the HVDC transmission using the impedance matrix of the current and voltage measurement components to perform harmonic elimination. This application can analyze the mismatch effects caused by the measurement components of the current transformer (CT) and its secondary system, and the current transformer (PT) and its secondary system, respectively, determine the system resonant frequency, and eliminate the resonance effect.