706 results about "Phase shifted" patented technology

The invention provides a VDSL ultra-low time delay communication method and system, and relates to the technical field of communication, and the method comprises the steps: encrypting a clock synchronization channel through a quantum key distribution protocol, dynamically dividing micro time slot resources in an orthogonal frequency division multiplexing symbol period, and generating a dynamically adjusted micro time slot resource distribution result; calculating an optimal phase offset matrix of the metasurface intelligent reflecting surface through a depth deterministic strategy gradient algorithm to obtain an optimized electromagnetic wave propagation path; generating a global optimization check matrix by aggregating the locally trained lightweight error correction model gradient of each node to obtain a compensated data stream; and constructing a causal graph model dynamic pruning high-entropy path to minimize causal entropy, through multi-agent reinforcement learning, taking time delay-energy efficiency as a game target to decide an optimal modulation order and a subcarrier switching strategy, and obtaining an optimized stable communication link. According to the invention, high-reliability and low-delay communication basic support is provided for high-precision intelligent manufacturing.

The invention relates to the technical field of electrical detection, in particular to an electricity meter load monitoring method and system based on an electric energy quality analyzer, and the method comprises the following steps: extracting three-phase voltage phase deviation characteristics in a disturbance period, combining with the comparison of a frequency band change trend and fundamental frequency power, recognizing an interference coupling section, and analyzing a jump frequency point; and outputting an ammeter load monitoring result. According to the method, the phase deviation angle of the three-phase voltage is extracted in the voltage disturbance period, and the cross-phase synchronization index is constructed, so that the synchronous response characteristics of different loads to disturbance can be accurately revealed, and the accuracy of load response attribution judgment is enhanced. On the basis of cross-phase synchronous analysis, a corresponding relation between frequency band characteristics and response attribution is constructed, so that load response subdivision has a phase difference identification capability and a frequency behavior calibration capability, and the discrimination robustness under a multi-source interference background is improved.

An apparatus includes a waveguide and one or more partially reflective surfaces embedded inside the waveguide, wherein each of the one or more partially reflective surfaces includes a multi-layer coating structure, wherein a first portion of the multi-layer coating structure induces an overall phase shift of light propagating through the first portion of the multi-layer coating structure and wherein a second portion of the multi-layer coating structure is selected to decrease the overall phase shift.

The invention provides a circulation power optimization method and system for a three-phase dual-active bridge, and relates to the field of power electronics, the method comprises the following steps: determining an optimal backflow modulation strategy set corresponding to a hybrid modulation group, the hybrid modulation group comprising triangular wave modulation, trapezoidal modulation, synchronous modulation and extended phase shift modulation, the optimal backflow modulation strategy set corresponding to the hybrid modulation group comprises modulation modes and degree-of-freedom relationships corresponding to different transmission power per unit value ranges in different voltage conversion ratio ranges; determining a degree of freedom and power relationship set corresponding to the hybrid modulation group, wherein the relationship set comprises a relationship between the degree of freedom and power of different transmission power per unit values corresponding to each mode; the phase shift angle, the primary side duty ratio and the secondary side duty ratio are determined by combining the real-time voltage conversion ratio and the real-time virtual power per unit value, operation of the three-phase dual-active bridge is controlled, and the method has the advantages of reducing complexity and improving portability and efficiency.

The present disclosure relates to the technical field of electromagnetic wave sensors, in particular to a signal transmitting, calibration, compensation and transceiving links, an integrated circuit, an electromagnetic wave sensor and a device, wherein the transmitting link includes an analog signal source and a digital phase shifter, the analog signal source may be configured to provide an initial analog signal, and the digital phase shifter may be configured to provide a phase shift signal in a digital domain and to perform phase shifting on the initial analog signal based on the phase shift signal, so as to perform a preset phase shifting operation on the initial analog signal, thereby effectively improving the phase modulation resolution and phase modulation accuracy.

A reconfigurable intelligent surface. The reconfigurable intelligent surface comprises a three-layer structure, comprising an artificial microstructure array capable of reflection and transmission within a specific frequency band range. By applying an external voltage to control the on / off of a semiconductor switch, an original phase shift structure is changed, ultimately achieving phase control of reflection and transmission. In addition, the structure is simple, can be realized by a microfabrication means, involves a mature process, and is easy to implement in high-frequency bands such as millimeter-wave and terahertz bands.

The invention provides a distributed feedback laser with a double-layer grating structure, and relates to the technical field of lasers, the laser forms an InGaAlAs multi-quantum well active region, an upper sampling grating layer and a lower phase shift grating layer on an n-type InP substrate in sequence, the upper grating layer is designed based on a reconstruction equivalent chirp technology, and the lower phase shift grating layer is designed based on a reconstruction equivalent chirp technology. Two sections of asymmetric modulation areas with sampling periods linearly gradually changing in opposite directions are arranged in the axial direction of the resonant cavity, and the lower grating layer is a quarter-wave phase shift grating matched with the period of the upper seed grating. Through the synergistic effect of equivalent phase modulation and phase shift generated by the double-layer grating, the photon density distribution in the cavity can be improved, the longitudinal space hole burning effect can be weakened, the sensitivity to end face phase fluctuation can be reduced, high single-mode power and large modulation bandwidth can be realized in a wide temperature range, and the double-layer grating is suitable for a high-speed optical communication and coarse wavelength division multiplexing transmission system.

The invention relates to the technical field of power system court management, and particularly discloses a court identification and user binding method based on a special transformer acquisition terminal, which comprises the following steps: separating harmonic interference generated by start and stop of an electric welding machine through a kurtosis index and time-frequency energy entropy fusion detection method, and extracting a fundamental voltage and a pure power signal; constructing a dynamic time bending model containing phase consistency and gradient feature constraint based on the fundamental wave voltage, and calculating voltage track similarity to judge electrical coupling; for the users with electrical coupling, dynamic weight power cross-correlation analysis is fused to generate a comprehensive decision value, and a space-time diagram neural network is utilized to update a transformer area topology structure online in combination with a historical topology change event, so that the dynamic determination of the transformer area to which the users belong is realized; through multi-dimensional feature fusion and anti-interference algorithm design, the problems of phase deviation and waveform distortion caused by electric welding machine harmonic waves are reduced, and the transformer area identification accuracy and real-time performance are improved.

The invention discloses a non-volatile phase shifter which is ultra compact and low in loss. In the non-volatile phase shifter, signal light is transmitted to the composite hybrid waveguide through the input waveguide and is modulated after passing through the phase change material area of the composite hybrid waveguide, and the phase change material is directly modulated through spatial light, so that the phase of the signal light is modulated. According to the invention, optical pulses with different pulse widths and different powers can be used, and the phase state of the phase change material can be regulated and controlled. The problems of large size area and high power consumption required by electro-optical regulation and control, thermo-optical regulation and control and the like are solved, pi phase shift can be realized in an interaction length as low as several microns, and meanwhile, relatively low loss is kept. According to the invention, the phase change material is regulated and controlled through spatial light, so that the distinguishable level up to 8 bits can be realized, and hyperfine phase regulation and control in an ultra-small structure can be realized. According to the invention, an excellent phase shifter design scheme can be provided for realizing complex photon circuits with ultra-compactness, ultra-low power consumption, low loss and the like.

The invention relates to a phase shifter and a base station antenna. The phase shifter comprises a circuit board (10) and a cavity (20), the circuit board (10) is located in the cavity (20), and the circuit board (10) is provided with a grounding connection end (11) and signal connection ends (12) of a plurality of phase shift circuits; the conductive part (70) is arranged in the cavity wall of the cavity (20) in a penetrating manner, and a part of structure of the conductive part (70) is electrically connected with the grounding connection end (11) of the circuit board (10); wherein the cavity (20) is provided with a cavity avoiding hole (22), and the cavity avoiding hole (22) is arranged opposite to the signal connecting end (12) and the grounding connecting end (11), so that the signal connecting end (12) and the grounding connecting end (11) are exposed from the cavity avoiding hole (22). According to the phase shifter and the base station antenna, electroplating-free effect can be realized, the occupied space is small, and the layout of the whole machine can be simplified.

The invention provides a multi-sub-array FD-RIS distance-angle beam regulation and control far field communication method and system, an FD-RIS is uniformly divided into a plurality of sub-arrays, and each sub-array adopts different modulation frequencies to realize diversity of frequency deviation. Besides, in order to control unexpected harmonic signals, a novel time modulation method is utilized to periodically adjust phase shifts of all reflection units of the FD-RIS, and unwanted harmonic signals can be effectively restrained. Different time delays are added in the time modulation process of each component so as to amplify the spatial degree of freedom of the FD-RIS to an expected harmonic signal, and the space control capability of the FD-RIS to the expected harmonic signal is prevented from being limited by a time modulation mode.

A control method of a dual active bridge converter, an energy storage device and a readable storage medium, the control method comprising: determining a feedforward value of an external phase shift angle and an adjustment value of the external phase shift angle according to an electrical parameter of the dual active bridge converter; and controlling the energy conversion of the dual-active bridge converter according to the feed-forward value of the external phase shift angle and the adjustment value of the external phase shift angle. When the dual active bridge converter performs energy conversion according to the generated driving signal, the feed-forward value of the external phase shift angle can be actively adjusted based on the target alternating current so as to adjust the given value of the external phase shift angle, so that the given value of the external phase shift angle can change along with the change of the target power supply current; therefore, the generated driving signal can actively adjust the output actual alternating current in time, and the purpose of reducing the output current or voltage waveform oscillation of the dual-active bridge converter is achieved.

The invention discloses a phased array distributed hierarchical control wave control system and a wave beam control method, and relates to the technical field of signal processing, the wave control system comprises a main control FPGA module, a plurality of sub-control FPGA modules and a plurality of T / R wave beam forming modules; the master control FPGA module is used for receiving a user instruction and outputting a phase shift control instruction according to the user instruction; the plurality of sub-control FPGA modules are in interactive connection with the main control FPGA module, and the sub-control FPGA modules are used for receiving the phase shift control instruction and outputting a phase shift code according to the phase shift control instruction; the plurality of T / R beamforming modules are respectively connected with the sub-control FPGA module and the antenna unit, and the T / R beamforming modules are used for receiving the phase shift codes and performing phase adjustment on the antenna unit according to the phase shift codes, so that not only can beam switching be quickly realized, but also the layout and wiring of a wave control board can be simplified, and the cost is reduced. And meanwhile, the requirements on the resources and the performance of the single FPAG and the cost of a wave control system are effectively reduced.

The utility model relates to the technical field of lasers, and discloses a high-slope-efficiency surface grating surface emitting laser which comprises a substrate, a lower waveguide layer, an active layer and an upper waveguide layer from bottom to top along the cross section. A ridge-shaped waveguide is formed in the middle area of the uppermost layer of the upper waveguide layer, and a Bragg grating is etched on the surface of the ridge-shaped waveguide; the Bragg grating comprises a section of second-order grating located in the middle and two sections of first-order gratings located at the two ends; a lambda / 4 phase shift is arranged in the second-order grating; the lambda / 4 phase shift is located in an etching area or a non-etching area of the first-order grating closest to the second-order grating; when the lambda / 4 phase shift is located in the etching region of the first-order grating closest to the second-order grating, the upward diffraction light power of the second-order grating is maximum, and the downward diffraction light power is minimum; when the lambda / 4 phase shift is located in the non-etching area of the first-order grating closest to the second-order grating, the upward diffraction light power of the second-order grating is minimum, and the downward diffraction light power of the second-order grating is maximum. According to the invention, high-slope efficiency lasing can be realized.

The invention discloses a smooth DPWM modulation method for realizing the optimal efficiency in a full power factor range, and the method comprises the steps: S10, carrying out the calculation of a three-phase current obtained through sampling and a given three-phase reference voltage, and obtaining a power factor angle; s20, judging the range of a power factor angle, and determining the size of a phase shift angle; s30, performing phase shift on the three-phase reference voltage to obtain a three-phase phase shift voltage; s40, the maximum value, the intermediate value and the minimum value of the three-phase phase shift voltage are obtained through calculation; s50, according to the size of the phase shifting angle theta, determining whether the phase shifting angle theta needs to be multiplied by a coefficient 2 or not; s60, calculating the maximum value and the minimum value of the three-phase reference voltage; s70, judging whether the absolute value of the maximum value of the three-phase phase shift voltage is greater than the absolute value of the minimum value of the three-phase phase shift voltage, and assigning the initial zero sequence voltage as 1-vmax or-1-vmin; s80, further judging the magnitude of an intermediate value between the zero-sequence voltage and the negative three-phase phase shift voltage, and further assigning the zero-sequence voltage as-vxmid, 1-vmax or-1-vmin; and S90, injecting the zero-sequence voltage into the three-phase reference voltage to obtain a three-phase modulation voltage.

The invention relates to the technical field of converter control, in particular to a novel four-level efficient grid-connected system and a control method, and the method comprises the steps: determining the target output power, the target input power, the actual output power and the actual input power of a converter based on a 4L-HCC converter; determining a phase angle and an output voltage amplitude based on a preset virtual synchronous machine control strategy, and converting to obtain a corresponding three-phase reference voltage; performing HCC internal capacitor voltage control on the converter, establishing a corresponding loss function, and determining a reference wave change range corresponding to each switching device on the converter based on actual setting; the corresponding reference wave signal with the minimum loss function derivative is calculated; and carrying out phase shift pulse width modulation on the converter, taking high-frequency triangular waves with different phases as carriers, comparing the calculated reference wave signals with the carriers, calculating the duty ratio of each switching device of the converter and a switch driving signal, and driving each switching device of the converter.

The invention discloses a DP-MZM-based reconfigurable mixer with phase shift and image rejection functions, and belongs to the field of microwave photon signal processing. By adjusting an input radio frequency signal and a direct current bias voltage of the DP-MZM1, four different LO frequency doubling and mixing functions can be realized. By controlling the angle alpha between the polarization direction of the polarization analyzer and one axis of the modulator, the phase of the generated signal can be flexibly tuned in the range of 0-360 degrees. When combined with the optical frequency comb, the multi-channel multi-band frequency conversion system can be expanded into a multi-channel multi-band frequency conversion system with independent phase tuning capability by utilizing the channel switching and frequency slot selection functions of the wavelength selection switch, and parallel output of various frequency mixing results can be realized. By adjusting the phase difference between the two-channel output signals, I / Q mixing, double-balanced mixing and image rejection mixing can be configured. The scheme is not influenced by direct current bias drift, the system complexity is reduced, and the frequency conversion efficiency is improved.

The invention discloses a permanent magnet synchronous motor multi-resistor current sampling method and a motor control system. The permanent magnet synchronous motor controls a three-phase inverter based on an SVPWM strategy, and successively samples two phases to be sampled in each control period. The sampling method comprises the following steps: judging whether a sampling window of a to-be-sampled short phase is smaller than first minimum sampling time or not; if yes, prolonging the conduction time of the short-phase lower bridge arm to the first minimum sampling time, and enabling the direction of the voltage synthesis vector obtained after prolonging to be unchanged; judging whether the sampling window of the to-be-sampled long phase is smaller than second minimum sampling time or not; if yes, the conduction time of the long-phase lower bridge arm is shifted rightwards; and successively collecting short-phase current and long-phase current in the current control period, and calculating three-phase current according to the short-phase current and the long-phase current. The maximum duty ratio of the upper bridge arm of the to-be-sampled two phases can be increased as much as possible by scaling and adjusting the proportion of the first sampled short phase and combining with the PWM waveform phase shift of the second sampled long phase, so that the maximum output capability of the motor is improved.

The invention relates to a reconfigurable intelligent metasurface which comprises a three-layer structure and comprises an artificial microstructure array with reflection and transmission in a specific frequency band range, an original phase shift structure is changed by controlling on-off of a semiconductor switch through external voltage, and finally phase control over reflection and transmission is achieved. Moreover, the structure is simple, can be realized through a micro-machining means, is mature in technology, and is easy to realize in high-frequency bands such as millimeter waves and terahertz.

The invention belongs to the technical field of electric power measurement, and discloses a calibration method and system of an intelligent measurement switch and a multi-switch synchronous measurement method, and the method comprises the steps: obtaining voltage and current waveform data of the intelligent measurement switch under a nonlinear load condition, and extracting a frequency spectrum feature matrix of the voltage and current waveform data; constructing an amplitude-phase coupling error model representing a nonlinear incidence relation between amplitude fluctuation and phase deviation, inputting the spectrum characteristic matrix into the amplitude-phase coupling error model, and calculating an amplitude-phase coupling error vector; performing vector decomposition on the amplitude-phase coupling error vector, and separating out an in-phase component error and an orthogonal component error; and generating a calibration compensation coefficient according to the in-phase component error and the orthogonal component error, and performing vector calibration on the intelligent measurement switch, thereby improving the calibration precision of the intelligent measurement switch.

The invention discloses a motor phase current sampling method and device, a chip and a motor controller, and the method comprises the steps: obtaining the duty ratio of a multi-phase bridge arm in a pulse modulation period; determining a to-be-sampled bridge arm according to the duty ratio; sampling a motor phase voltage corresponding to the to-be-sampled bridge arm in a target sampling time period corresponding to the to-be-sampled bridge arm, and determining a corresponding motor neutral point voltage; wherein the target sampling time period is a time period from the start of a dead zone corresponding to the to-be-sampled bridge arm to the completion of follow current; and determining a motor phase current corresponding to the to-be-sampled bridge arm according to the motor phase voltage corresponding to the to-be-sampled bridge arm and the corresponding motor neutral point voltage. According to the method, the sampling function of the motor phase current can be realized without phase shift and sampling point calculation, the algorithm is simple, harmonic waves are not generated, and the phase current sampling cost is relatively low.

The present invention belongs to the field of electromagnetic functional devices, and specifically relates to a fin-line terahertz multi-phase shifter based on a gallium arsenide diode, comprising: a rectangular waveguide input port, a substrate, a rectangular waveguide-fin-line transition structure, a fin-line structure, a probe-type microstructure phase shifter unit, its feeding opening portion, a fin-line-rectangular waveguide transition structure, and a rectangular waveguide output port. The present invention addresses the problems of the existing terahertz wave phase modulator having few phase shifting technical solutions, large insertion loss during phase shifting, a small phase shift range, a large device size, and low integrability. By controlling the on-off of the diode on the probe-type microstructure phase shifter unit by voltage, the perturbation intensity of the probe on the fin line is changed, so that the equivalent dielectric constant of the fin line changes, thereby achieving the phase shift of the terahertz wave; then, by superimposing the phase shifters in a centrally symmetrical and parallel arrangement, a low-insertion-loss multi-bit terahertz wave phase shift is finally achieved, ensuring a good working state and promoting the development of terahertz phase control technology.

According to an aspect of the present inventive concept there is provided a laser system for generating a frequency modulated continuous wave, FMCW, light signal, the system comprising: a tunable laser for generating the FMCW light signal; an optical measurement unit configured to receive a portion of the FMCW light signal, and to output, via an optical hybrid coupler, at least two angle diversity signals based on a difference between a first and second signal formed by splitting the portion of the FMCW light signal wherein the second signal is delayed relative to the first signal, wherein a pair of signals of the at least two angle diversity signals have a fixed phase shift relative to each other; and a control unit configured to: receive the at least two angle diversity signals, estimate, based on the at least two angle diversity signals, a compensation needed for adjusting a non-linearity of a frequency chirp of the tunable laser, and output a corresponding control signal to the tunable laser, wherein the control signal is configured to improve a linearity of the frequency chirp.

The invention discloses a surface topography measurement device and method based on polarization phase shift. The device comprises a laser module, a polarization beam splitting and interference module, a polarization beam combining and imaging module, a polarization image acquisition module and a control and reconstruction module. The laser module comprises a monochromatic tunable laser, an optical fiber collimating amplifier and a polarizer; the polarization beam splitting and interference module comprises a polarization beam splitting prism, a first quarter-wave plate, a plane mirror and a second quarter-wave plate; the polarization beam combining and imaging module comprises a polarization splitting prism, a third quarter-wave plate and a telecentric lens; the polarization image acquisition module comprises a micro-polarization array camera and an image processing unit, and the micro-polarization array camera synchronously acquires four polarization interference images through single exposure; and the control and reconstruction module obtains measurement data of the surface topography of the to-be-measured object through a phase unwrapping algorithm and three-dimensional topography reconstruction. According to the invention, high-precision, large-field-of-view, portable and high-efficiency field detection can be realized.

The invention provides a pipettor automatic calibration positioning and accuracy evaluation method based on photoelectric sensing, and relates to the technical field of pipettor calibration, and the method comprises the following steps: arranging an annular photoelectric sensor array to collect interference fringe phase difference, liquid level reflection light signals and surface acoustic wave signals, and adopting a five-step phase shift method to obtain a three-dimensional displacement vector; dynamic calibration is achieved through liquid level morphological parameter analysis in combination with adaptive Kalman filtering, numerical simulation is conducted on the liquid drop forming process through time-frequency analysis and a fluid mechanics model, and finally the accuracy is evaluated through adaptive fuzzy reasoning and Bayesian estimation. According to the invention, high-accuracy automatic calibration and evaluation of the pipettor are realized.

An illustrative sensor controller includes: a transmitter, a receiver, a time-of-flight circuit, and a phase shift circuit. The transmitter is configured to provide a drive signal to an ultrasonic sending transducer to generate an acoustic burst. The receiver is configured to receive a response signal from an ultrasonic receiving transducer. The time-of-flight circuit is configured to detect an arrival of the acoustic burst in the response signal and to measure a first time of flight associated with that arrival. The phase shift circuit is configured to measure a phase shift of the acoustic burst in the response signal and to determine a second time of flight corresponding to the phase shift.

A method of controlling a reconfigurable intelligent surface (RIS) is provided for multi-target spot beamforming at a plurality of target beam focus positions. The RIS includes a 2D array of unit cells, each unit cell being controllable to be at any selected one of a plurality of wave propagation path states for providing a corresponding degree of phase shift for an incident electromagnetic wave irradiated thereon. The method includes: for each of the plurality of target beam focus positions: determining, for each unit cell of the plurality of the 2D array of unit cells, an interference pattern at the unit cell between a reference wave from a multi-mode orbital angular momentum (OAM) signal transmitter to the unit cell and an object wave from the target beam focus position to the unit cell, the multi-mode OAM signal transmitter being configured to generate and transmit a multi-mode OAM signal to irradiate the RIS at a surface thereof; and for each unit cell of the plurality of the 2D array of unit cells: determining a holograph pattern based on the interference patterns determined at the unit cell for the plurality of target beam focus positions; determining a degree of phase shift for the unit cell to provide based on the holograph pattern determined for the unit cell; and controlling the unit cell to be at a selected one of the plurality of wave propagation path states corresponding to the degree of phase shift determined for the unit cell to provide. There is also provided a corresponding RIS controller and a corresponding multi-target spot beamforming system.

The application discloses a laser cavity diagnosis device and method based on double-frame delay synchronization phase shift, which comprises an excitation module and a detection module; the excitation module comprises a first laser, a first 1 / 2 wave plate, a polarization beam splitter prism, a beam splitter, an energy meter, a convex lens and a water tank; the detection module comprises a second laser, a beam expander lens group, a second 1 / 2 wave plate, a second polarization beam splitter prism, a third 1 / 2 wave plate, a first reflector, a second reflector, a fourth 1 / 2 wave plate, a third polarization beam splitter prism, a third reflector, a fourth polarization beam splitter prism, a first 1 / 4 wave plate, a first imaging lens, a first micro-polarization camera, a second 1 / 4 wave plate, a second imaging lens and a second micro-polarization camera. The application introduces a double-frame delay method in the traditional synchronous phase shift interference, overcomes the defects of the existing cavity detection technology, and realizes the observation of the instantaneous phase change in a single cavity pulsation period.

The invention provides a carrier phase shift dynamic allocation method and system of a modular multilevel converter, which can identify the number and position of fault modules, calculate the phase shift stepping value of symmetrical carrier phase shift in real time, and reconstruct the mapping relation between sub-modules and carriers, so that a controller realizes dynamic carrier allocation, and the dynamic allocation efficiency of the carrier phase shift of the modular multilevel converter is improved. Even in a redundant mode, symmetry of carrier waves can be realized, and switching frequency is equivalently improved, so that current and voltage ripples are reduced, the problems of non-uniform carrier wave distribution and disappearance of frequency equivalent multiplication effect caused by bypass of a fault module of an existing modular multilevel converter are solved, the overall performance and electric energy quality of a power system are improved, and the service life of the power system is prolonged. Dynamic changes of health states of the modules can be adapted in real time, synchronization among the modules is kept, the efficiency of a power system is improved, harmonic distortion is reduced, and the reliability and adaptability of the modular multilevel converter and the overall performance of the power system are improved.

The invention discloses a phase shift migration-based ultrasonic array imaging method for defects in a steel ingot, which comprises the following steps of: performing two-dimensional Fourier transform on full-matrix time domain data obtained by ultrasonic array detection of the steel ingot to obtain a two-dimensional frequency spectrum of the full-matrix data, and establishing a relationship between a transmitting sound field and a receiving sound field; and gradually extrapolating the sound field through a phase shift factor in the depth direction, recovering a time domain sound field signal through two-dimensional inverse Fourier transform, and obtaining a focusing imaging result in the steel ingot according to the correlation between the transmitted sound field and the received sound field. The method has the characteristics that the image resolution is improved, the method adapts to sound velocity change in a complex medium, complex calculation is not needed, and the calculation efficiency is high.