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14 results about "Synchronous coordinates" patented technology

In general relativity, a synchronous reference system is a coordinate system in which the metric takes the form , where the Latin indices a and b are summed over the spatial directions and is a spatial metric. Any metric can locally be put into this form by a coordinate transformation. This coordinate condition is called "synchronous" because the t coordinate defines proper time for all comoving observers. However, it is not uniquely defined, and therefore is not a gauge, as the spacelike hypersurface at can be chosen arbitrarily. Another problem with the reference system is that caustics can occur which cause the gauge choice to break down. These problems have caused some difficulties doing cosmological perturbation theory in this system, however the problems are now well understood. Synchronous coordinates are generally considered the most efficient reference system for doing calculations, and are used in many modern cosmology codes, such as CMBFAST. They are also useful for solving theoretical problems in which a spacelike hypersurface needs to be fixed, as with spacelike singularities.

On-line detection and sorting control method and system for die cutting defects of pole piece

The invention discloses a pole piece die cutting defect online detection and sorting control method and system, particularly relates to the technical field of pole piece die cutting online detection and sorting control, and is used for solving the problems of uncertain event positioning and sorting errors caused by time base asynchronization, coordinate mapping drifting and late disorder under a multi-station dynamic beat condition. A double-anchor time base and an idempotent key are established, water line propulsion and out-of-order window playback are taken as an order basis under a unified time axis, online self-certification of same-layer coordinate transformation and time check and space check in a topological graph are matched, unified judgment is implemented at the merging moment, and two-section interlocking execution is performed. Therefore, under the multi-station dynamic rhythm, a determined and reviewable sheet-level corresponding relation is established between the detection event and the stroke frequency, the mold cavity and the discharging port, the consistency of sorting decisions is still kept in the face of late, disorder and state transition, and the risk of wrong sorting and missing sorting is reduced.
Owner:SHUANG YILI (TIANJIN) NEW ENERGY CO LTD

Dual-channel electric drive multiplexing type vehicle-mounted charging system unbalanced current suppression method

The invention discloses a dual-channel electric drive multiplexing type vehicle-mounted charging system unbalanced current suppression method, which comprises the following steps of: firstly, popularizing and applying a positive and negative sequence separation method for decoupling a dual-synchronous coordinate system to a dual-channel six-phase motor, and calculating positive and negative sequence components of a dq axis of a dual-channel system under a current unbalanced working condition; utilizing Park and VSD transformation to map the data to an alpha beta xy0102 sub-plane; secondly, setting a positive-sequence current given value and a negative-sequence current given value to be 0 by using a six-phase current distribution method for minimizing electromagnetic torque; then, independent PI control is carried out on each sub-plane; and finally, correspondingly adding the output quantities of the positive sequence current and the negative sequence current of each sub-plane, returning to a natural coordinate system through TVSD-1, and then outputting SPWM, thereby realizing a three-phase charging working condition. According to the method, the suppression of the negative-sequence current can be realized, the sine degree of the power grid current is improved, the torque ripple is suppressed, and the system safety is guaranteed.
Owner:NANTONG UNIV

Wind turbine generator rotor voltage dynamic compensation control method and system

The embodiment of the invention relates to the technical field of wind turbine generator control, and provides a dynamic compensation control method and system for a rotor voltage of a wind turbine generator, and the method comprises the steps: decomposing a power grid voltage and a rotor current into a positive-sequence component and a negative-sequence component in real time through constructing a self-adaptive decoupling control architecture based on a dual-synchronous coordinate system; a positive-sequence channel is responsible for accurately tracking active and reactive power instructions and guaranteeing a power generation task, and a negative-sequence channel is responsible for accurately tracking a positive-sequence channel and a negative-sequence channel; the negative sequence channel aims at eliminating negative sequence current and suppresses second harmonic pulsation; a dynamic compensation gain mechanism is further introduced, the fault severity is evaluated by quantifying the unbalance degree of a power grid in real time, and the intensity of negative sequence compensation is adaptively adjusted, so that the control strategy can maximally suppress pulsation when a slight fault occurs, and the safety of the converter is preferentially guaranteed and the overcurrent risk is avoided when a serious fault occurs.
Owner:HUANENG HUILI WIND POWER GENERATION CO LTD +2

Position sensorless control method, device and system of permanent magnet synchronous motor

The invention relates to a position sensorless control method, device and system of a permanent magnet synchronous motor. According to the method, an inductance differential term under a motor voltage equation in a synchronous coordinate system is subjected to approximate processing, a novel counter electromotive force is defined, a full-order observer based on the novel counter electromotive force is designed for position observation, global convergence of the full-order observer is proved, and therefore it is guaranteed that the full-order observer is stably started at the zero speed. Through error analysis, a current control strategy is designed to avoid the influence of a resistance error on position observation. Compared with a traditional observer, the full-order observer based on the novel back electromotive force has the advantages that no d-axis inductance exists in a state equation, and therefore the influence of the d-axis inductance on position observation can be ignored. Compared with an existing high-frequency signal injection method technology, the method can achieve sensorless control and on-load inversion at zero low speed without signal injection, avoids high-frequency noise generation and extra energy loss, and has a wide industrial application prospect.
Owner:TONGJI UNIV

A multi-port motor driver power distribution control method based on double synchronous coordinate system

The application discloses a kind of based on the power distribution control method of multi-port motor driver of double synchronous coordinate system, first decoupling modeling is carried out to multi-port motor driver, according to its output voltage, it is equivalent to two independent two-level sub-driver units, to decouple the power flow path of first and second DC source;Establish the port power relationship between multi-port motor driver and sub-driver unit;Then according to the first DC source port reference power, directly adjust the shaft reference voltage of two sub-driver units;Again based on interleaved clamping, constrain the switching times of each sub-driver unit, obtain the correlation expression of shaft reference voltage by constraint condition, and then obtain complete shaft reference voltage;After coordinate transformation and zero sequence voltage injection, generate the final three-phase modulation signal;Finally, the three-phase modulation signal is compared with triangular carrier, to generate drive signal, to control each bridge arm switch tube.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA +1

On-line detection, sorting and control method and system for pole piece die-cutting defects

The application discloses a method and system for online detection and sorting control of pole piece die cutting defects, and particularly relates to the technical field of online detection and sorting control of pole piece die cutting, and is used for solving the problems of event landing uncertainty and sorting error caused by time base asynchronization, coordinate mapping drift and late disorder under the condition of multi-station dynamic rhythm. Through the establishment of double-anchor time base and idempotent key, on the basis of water line promotion and disorder window playback as the order under the unified time axis, combined with online self-proving of coordinate transformation of the same layer and time calibration and space calibration in the topological graph, unified decision is implemented at the merging moment and two-section interlocking is executed, so that the pole piece detection event is established in a determined and reviewable piece-level corresponding relationship with the punching frequency, die cavity and discharge port under the condition of multi-station dynamic rhythm, and the consistency of sorting decision is maintained and the risk of misclassification and missed classification is reduced in the face of late arrival, disorder and state transition.
Owner:SHUANG YILI (TIANJIN) NEW ENERGY CO LTD

Drive control device, drive control system, and state estimation method

PendingUS20260189165A1Control vectorControl system
Based on Ts (=2×Tc=Th), a control cycle for performing sensor-less vector control-related process, an estimator applies synchronously with Ts and Tc, high-frequency voltage having cycle Th corresponding to frequency outside audible range on γ-axis of γδ semi-synchronous coordinate system, detects stator current including basic drive frequency component and high-frequency component at cycle Tc, time-differentiates two most recent detected values of stator current on γδ semi-synchronous coordinate system per cycle Ts, to generate either or both of γ-axis component signal cγ and δ-axis component signal sδ, generates positive correlation signal pc having positive correlation with deviation between the rotor phase and the γ-axis phase per cycle Ts by using the generated axis component signal, and performs signal processing of positive correlation signal pc such that positive correlation signal pc becomes zero, to generate estimated value of the phase or the speed of the rotor.
Owner:MINEBEAMITSUMI INC

A three-phase grid-connected inverter admittance identification method based on complex-valued neural network

This invention discloses a method for identifying the admittance of a three-phase grid-connected inverter based on a complex-valued neural network, relating to the field of power electronics technology. The method includes: constructing a small-signal flow graph of the three-phase grid-connected inverter in a synchronous coordinate system; constructing a port admittance matrix at the steady-state operating point; determining the corresponding characteristic polynomial and factoring it to obtain a unified pole set; constructing the pole-residual expansion of the port admittance matrix based on the unified pole set; determining the transfer function of each element in the port admittance matrix; constructing a complex-valued neural network and its loss function; training the complex-valued neural network using the loss function; and inputting the operating condition information and frequency point of the grid connection point into the complex-valued neural network to obtain the port admittance under the current operating condition. This method has the technical advantages of low computational complexity, high identification efficiency, support for rapid identification under multiple operating conditions, and high physical interpretability of the fitting results.
Owner:SICHUAN UNIV

Vehicle intelligent network connection test system based on cross-layer collaborative architecture

The invention relates to the technical field of new energy vehicles, and discloses a cross-layer collaborative architecture-based vehicle intelligent network connection test system, which comprises the following steps of: establishing a tunnel longitudinal position system taking a semi-closed tunnel door opening reference surface as a space starting point, and mapping multi-source acquisition data to the tunnel longitudinal position system to construct a cross-layer state data set; extracting interference values such as enclosure surface reflection, illumination transition, positioning attenuation and communication attenuation according to the set, fusing to generate a composite distortion density, and calculating an interval midpoint and width of a preposed contraction high-risk interval according to the composite distortion density; maximizing the response change rate of the vehicle application layer in the high-risk interval by adopting a particle swarm algorithm so as to obtain an optimal test control instruction set; executing a test based on the instruction set, and remapping each layer of data to an interference synchronization coordinate system; and finally, calculating a trigger concentration point and a distortion concentration point of an application layer, quantifying a trigger offset to determine a core failure reason, and solidifying the core failure reason into a test template and an execution script.
Owner:SUZHOU YUANCE SHUCHI TECHNOLOGY CO LTD

A method for compensating phase delay error of a brushless direct current motor

The application discloses a compensation method for phase delay error of a brushless direct current motor, which comprises the following steps: collecting three-phase current data of the brushless direct current motor in real time; constructing an adaptive linear neuron filter based on a recursive least square method in a DSP to extract three-phase current fundamental waves; converting the three-phase current fundamental waves to a synchronous coordinate system through coordinate transformation to obtain d-axis current; outputting the difference between the d-axis current and 0 to a PI regulator, wherein the output of the PI regulator is a phase compensation angle; through adaptive compensation for several periods, the PI regulator tends to be stable, and finally the output compensation angle is the optimal phase compensation angle under the working condition. The method accelerates the convergence speed of a weight factor by means of the improved Adaline filter, improves the steady-state accuracy, and has the advantage of improving the operation efficiency of the brushless direct current motor.
Owner:DALIAN MARITIME UNIVERSITY

Bisynchronous coordinate system phase-locked loop optimization strategy

The invention discloses a dual-synchronous coordinate system phase-locked loop optimization strategy which comprises a Clarke transformation unit, a Park transformation unit, an iPark transformation unit, a positive sequence decoupling network, a negative sequence decoupling network, a low-pass filter, a PI regulator and a frequency integration unit. When the amplitude of one-phase or two-phase voltage is zero, one-phase voltage with the amplitude not zero is selected, and a single-phase phase-locked loop lock is adopted for phase locking; and when the amplitudes of the three-phase voltages are not zero, Clarke conversion is carried out on the three-phase voltages, and the frequency is assigned to an integral quantity of a PI regulator of the three-phase phase-locked loop, so that the phase-locked loop of the double-synchronous coordinate system jumps out of a pseudo-steady state. Different coping strategies are determined to be adopted according to different voltage conditions, and the problem that the phase-locked loop of the double-synchronous coordinate system enters a pseudo-steady state is effectively prevented.
Owner:BEIJING DAHUA RADIO INSTR FACTORY

Synchronous coordinate system phase-locked loop based on performance excitation anti-saturation control

PendingCN121864091ACumulative offset releaseImprove grid connection reliabilityPulse automatic controlLoop filterPhase detector
The invention discloses a synchronous coordinate system phase-locked loop based on performance excitation anti-saturation control. The synchronous coordinate system phase-locked loop is composed of a phase detector, a loop filter, an artificial amplitude limiter, an anti-saturation feedback loop, a voltage-controlled oscillator and a performance excitation loop. An artificial amplitude limiter is arranged between a loop filter and a voltage-controlled oscillator, so that the variation amplitude of a frequency estimator is limited, and frequency divergence caused by depth disturbance is inhibited. And meanwhile, an anti-saturation feedback loop is constructed by using a difference value between input and output of the amplitude limiter, the recovery process of an integration link is accelerated when saturation occurs, and the attraction domain of a closed-loop system is expanded. Besides, a tracking error formed by a phase estimation value of the phase-locked loop and an expected value is introduced into a performance excitation loop for adjusting the starting opportunity of anti-saturation compensation and improving the dynamic performance in different operation scenes. According to the scheme, the stable phase tracking capability can be kept in a complex electric energy environment, and the synchronization reliability of the converter is improved.
Owner:SHANGHAI JIAOTONG UNIV

Multi-modal sensor fused moving object positioning method and device

The invention discloses a moving object positioning method and device based on multi-modal sensor fusion, and belongs to the technical field of multi-sensor fusion and computer vision. In order to solve the problems that a single IMU has drift errors and a single visual system is influenced by illumination and shielding, high-frequency dynamic data of the IMU and low-frequency but high-precision visual information provided by a fixed camera are effectively combined through the steps of time synchronization, coordinate system calibration, extended Kalman filtering fusion, error optimization and the like. The system firstly performs interpolation alignment on the asynchronously acquired IMU and image data, and then unifies the IMU and image data to a world coordinate system; then, the state is predicted through an IMU by means of an EKF, drifting is corrected through image feature points, and finally high-precision and high-robustness three-dimensional positioning and attitude estimation are achieved. The method is suitable for medical ultrasonic scanning assistance, robot navigation, augmented reality, unmanned driving and other application scenes with limited GPS or complex environment, and has the advantages of high real-time performance, high precision, wide adaptability and the like.
Owner:NANKAI UNIV

Method and system for drivetrain load mitigation of grid-forming doubly-fed induction generator-based wind turbine generators based on phase angle feedforward

A method for drivetrain load mitigation of grid-forming (GFM) doubly-fed induction generator (DFIG)-based wind turbine generator (WTG) based on phase angle feedforward, wherein: acquiring active power of a GFM DFIG-based WTG; calculating difference value between acquired active power of GFM DFIG-based WTG and active power reference value; inputting difference value into GFM control to obtain output signal; adding output signal and reference frequency value of virtual synchronous coordinate system to obtain frequency of virtual synchronous coordinate system; integrating the frequency to obtain output value; multiplying additional damping active power reference value of GFM DFIG-based WTG by control gain of phase angle feedforward control to obtain product result; adding product result and output value to obtain angle of virtual synchronous coordinate system, and based on the angle, obtaining control quantity for generator output voltage phase; based on control quantity, adjusting phase of actual output voltage of GFM DFIG-based WTG by controlling rotor excitation current.
Owner:SHANDONG UNIV