10 results about "Circuit equation" patented technology

The application provides an asymmetric short-circuit current calculation method and system for large-scale new energy stations, and the method comprises the following steps: judging a fault type and a fault phase; constructing a fault composite sequence network; calculating negative sequence impedance of each new energy station, and calculating positive sequence initial voltage of each new energy station; calculating output short-circuit current of each new energy station; obtaining a simplified equivalent circuit through circuit simplification according to the fault composite sequence network; calculating positive sequence voltage of each new energy station; comparing the positive sequence voltage of each new energy station with the positive sequence initial voltage, judging whether a voltage difference meets convergence accuracy, solving output negative sequence current and zero sequence current of each new energy station according to a circuit equation; and outputting output phase current of each new energy station. The application overcomes the influence of a converter control on a phase selection element, can effectively shorten the iteration number, avoids the process of solving matrix inverse operation by using a node voltage method, has good engineering practicability and precision, and can be applied to large-scale new energy stations.

The application discloses a kind of energy storage converter asymmetric fault analysis methods based on virtual synchronous machine technology, using the vector control strategy based on internal potential orientation, grid-connected point voltage is separated into positive and negative sequence;According to asymmetric fault scene adjustment control link, including using trap filter to filter out the two-frequency fluctuation component in inverter output power, the reference voltage in reactive-voltage loop is switched from rated voltage to grid-connected point positive sequence voltage, negative sequence is inhibited by balance current strategy;Based on reactive-voltage circuit equation and reactive-voltage control equation, establish the equation about internal potential;According to virtual impedance ring control equation, calculate current reference value before fault and substitute into the virtual impedance ring control equation after Laplace transform, establish the equation about fault current dq axis component;According to the equation about internal potential and the equation about fault current dq axis component, construct the analytical expression of fault current.The application considers the influence of inverter control link on fault current transient characteristic, and analytical precision is high.

The invention discloses a field-circuit coupling method and device based on a time domain hybrid finite element method and a delay insertion method. The method comprises the following steps: discretizing a three-dimensional electromagnetic structure through a tetrahedral mesh, reading the port characteristics of an IBIS model, constructing an electromagnetic field equation based on a hybrid finite element algorithm of tree-cotree decomposition, and reducing the order through a modal order reduction technology after discretization; an electromagnetic port is equivalent to a series structure, the series structure is coupled with an IBIS model equivalent circuit to construct an EM-IBIS system, and a circuit equation is solved through an LIM method; a self-adaptive local time step length strategy is adopted, an electromagnetic part adopts large-step-length propulsion, and a circuit part is subjected to self-adaptive subdivision iteration in each electromagnetic step length until a convergence condition is met. Simulation precision and efficiency are balanced, full-link simulation is supported, the design reliability of a high-speed and high-density electronic system can be improved, and the method has important application value in scenes such as signal integrity, power supply integrity and electromagnetic compatibility optimization.

This invention relates to a rapid calculation method for loop parameters of a high-voltage power supply and utilization experimental device, belonging to the technical field of short-circuit breaking tests for large-capacity high-voltage electrical appliances. The method employs a direct method using the output of an impulse generator to establish the corresponding test loop circuit topology, simplifying it to a single-phase equivalent calculation circuit with the first open pole. Based on this circuit, a third-order circuit equation for the TRV waveform to be solved is established. For the third-order circuit equation of the waveform, engineering simplification conditions are substituted to simplify it into a series discharge solution, yielding simplified and per-unit solutions. The equations for the simplified and per-unit solutions are then dimensionless, reducing their dimensionality. Based on the dimensionless equation of the dimension-reduced waveform, the test voltage, dimensionless parameters, and peak time are substituted sequentially to calculate the initial values ​​of the device loop parameters. This invention can significantly improve the efficiency of short-circuit breaking tests in large-capacity test stations.

The invention provides a simulation training system for a secondary circuit of a power system and a working method of the simulation training system. The simulation training system comprises a simulation construction module, a circuit calculation engine, a virtual tool module and a defect simulation module. Wherein the simulation construction module is used for constructing a target secondary circuit simulation model comprising a terminal strip and multiple components. According to the circuit principle, a circuit equation is constructed and solved, node potentials are calculated, and component states are iteratively updated, so that the dynamic working process of a loop is simulated. Wherein the virtual tool module provides at least one virtual maintenance tool for a user to measure or operate the simulation model and perform loop state diagnosis or defect repair. Wherein the defect simulation module is used for presetting at least one type of circuit defect in the simulation model and creating a fault scene for training.

The invention discloses a method for estimating the real-time short-circuit capacity of a superior common connection point of a bilateral traction power supply system, and aims to effectively solve the technical problem that the short-circuit capacity of the superior common connection point of the bilateral traction power supply system cannot be calculated in real time. And solving the real-time short-circuit capacity of the superior power grid of the traction power supply system in combination with system electrical structure characteristics. The method comprises the following steps: step 1, listing circuit equations of a branch 1 and a branch 2; 2, listing a circuit equation of a branch 3; 3, estimating the short-circuit capacity of the node 3; and step 4, estimating the superior short-circuit capacity.

The present application relates to the technical field of lithium ion battery state estimation, in particular to a low-temperature lithium battery SOC estimation method based on PIKAN-LSTM, which firstly carries out low-rate discharge test under multiple temperature environments, constructs the relationship curve of open-circuit voltage, state of charge and temperature, and completes the training and verification of the first KAN model; then builds a PIKAN model containing a circuit equation solving unit and a second KAN network unit, identifies the battery equivalent resistance and two-stage polarization voltage in combination with the second-order RC equivalent circuit equation; then obtains the estimated open-circuit voltage through voltage compensation operation, inputs the first KAN model to output the preliminary state of charge; finally, the time series error correction is carried out by using the bidirectional LSTM network to obtain the final estimation result, which effectively solves the problems of battery model parameter drift and estimation error accumulation under low-temperature working conditions, and significantly improves the estimation accuracy and robustness.

The application relates to the technical field of wireless power supply, in particular to a multi-relay wireless power supply system modeling method, which comprises the following steps: S1, constructing a circuit equation based on an impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and performing LDU decomposition on the impedance matrix of the system to obtain a lower triangular impedance matrix, a diagonal impedance matrix and an upper triangular impedance matrix; S2, performing forward voltage transformation according to the lower triangular impedance matrix and a system input voltage phasor; S3, solving forward current according to the diagonal impedance matrix and the forward voltage; S4, performing backward current transformation according to the upper triangular impedance matrix and the forward current to solve loop currents of the multiple relay coils. The method can clearly describe the cross-coupling relationship between the coils of the multi-relay wireless power supply system, can decompose the coil composition of each loop, and can be used for analyzing the input, output and other characteristics of the multi-relay wireless power supply system under complex cross-coupling.

The invention relates to a distributed photovoltaic new energy aggregation overall impedance modeling method and device.The modeling method is based on a harmonic linearization method, modeling is conducted according to a photovoltaic inverter main circuit equation, a power outer loop and a voltage and current inner loop control equation, and a photovoltaic inverter impedance model considering frequency coupling is obtained; and the inverter and a power grid are regarded as a whole by combining frequency coupling characteristics, and an overall impedance model of the new energy grid-connected system containing the photovoltaic inverter is obtained. The method can accurately characterize the overall frequency domain characteristics of the photovoltaic inverter system under the influence of power grid impedance, and is suitable for stability analysis of a grid-connected system.

The invention provides an energy storage battery internal short circuit detection method based on a short circuit equivalent circuit model, and belongs to the technical field of batteries, and the method comprises the steps: firstly constructing an equivalent circuit model comprising a normal branch and a short circuit branch which are connected in parallel, a circuit equation corresponding to an equivalent circuit model serves as a physical constraint term to be embedded into a loss function of a physical information neural network for model training, electrical parameters, a thermal model, short-circuit inductance and other multi-physical-field information are fused, and finally the internal short-circuit occurrence probability with a confidence interval is output. The method solves the problem that early detection sensitivity and reliability of the internal short circuit are difficult to consider at the same time, early sensitive detection and reliable verification of the internal short circuit of the battery are achieved, and the safety early warning capacity of an energy storage system is remarkably improved.