354 results about "Virtual impedance" patented technology

The invention discloses an energy storage system real-time diagnosis and networking control method and system based on digital twinning and deep learning, and the method comprises the steps: collecting the electrical, thermal and aging state data of an energy storage battery cluster through a multi-mode sensor, constructing a multi-physics field coupled digital twinborn model by using a graph neural network and a long short-term memory network; performing synchronous mapping on battery cluster operation data acquired in real time and the digital twinborn model to generate a state evolution sequence in the battery cluster with advanced prediction capability; based on the state evolution sequence, predicting a dynamic stability boundary of the key node of the power grid and a possible instability risk time period in the future; and according to the dynamic stability boundary and the instability risk time period, generating a cooperative adjustment instruction of the output voltage amplitude, the phase and the virtual impedance of the network construction type energy storage equipment. According to the embodiment of the invention, the diagnosis reliability, the control foresight and the operation safety of the energy storage system in a complex power grid environment can be improved.

A low voltage ride through control method for a grid-forming inverter based on dynamic internal potential adjustment comprises the following steps: detecting a voltage per unit value of a grid-connected point in real time, and comparing the voltage per unit value with a threshold value to judge a voltage drop event and trigger low voltage ride through control; dynamically calculating active and reactive power reference values through a reactive compensation equation and an active current limiting equation according to the voltage amplitude and the power reference value before falling during the ride-through period; inputting the active reference value into a virtual rotor motion equation to generate a reference phase, and outputting a phase reference signal in combination with a dual-mode phase compensation controller; superposing the reactive reference value with the reference voltage through a reactive voltage regulating ring to generate a voltage amplitude reference signal; synthesizing an internal potential according to the phase and the amplitude reference signal, and obtaining an inductive current reference value through virtual impedance control and current amplitude limiting; and finally, a driving signal is generated through the current inner loop controller and the modulation module. According to the invention, overcurrent can be effectively inhibited, rapid reactive power support is provided, and synchronous stability and smooth transition in a fault period and a recovery process are ensured.

The invention discloses a converter collaborative current limiting method based on adaptive virtual impedance and a power loop, and the method comprises the steps: firstly building an equivalent impedance model of a converter and a power grid, analyzing the steady-state and transient characteristics of fault current, and extracting key parameters for current limiting design; when it is detected that the voltage drop of the grid-connected point exceeds a threshold value, a self-adaptive virtual impedance link is automatically put into use, and virtual resistance and reactance values are dynamically calculated according to the variation amplitude of voltage or current, so that the virtual resistance and reactance values are proportionally adjusted along with the fault degree; and when the system voltage returns to normal, the virtual impedance automatically quits, and the control continuity is ensured. Then, the active and reactive power reference values are dynamically corrected according to the voltage drop depth, a power reference signal matched with the voltage amplitude is generated, it is guaranteed that power output does not exceed the limit, and the voltage supporting capacity is improved. Finally, real-time current-limiting control of the converter and stable operation of the system are realized on the premise of not switching the control mode through the synergistic effect of the virtual impedance ring and the power ring. The method has the advantages of being high in response speed, excellent in current limiting effect, good in control continuity and the like, and is suitable for fault current limiting and voltage support control of the grid-forming converter.

The invention belongs to the field of stability analysis of a grid-connected system of a grid-building converter, and particularly relates to a grid-building converter grid-connected resonance risk analysis method considering virtual impedance, which comprises the following steps: S1, establishing a three-phase time domain differential equation and simplifying the equation into a single-phase equivalent time domain model; converting into a harmonic state space model of the main circuit; s2, constructing a harmonic state space model of a control system comprising an active power control loop and a reactive power control loop; s3, introducing a virtual impedance control link, and correcting the voltage amplitude reference phasor output by the reactive power control loop; deriving an expression of a modulation signal disturbance phasor; s4, obtaining a complete frequency domain admittance model YGSC of the network construction converter considering the influence of the virtual impedance; an open loop gain TGFM of the grid converter grid-connected system is constructed; and S5, drawing a Nyquist curve based on TGFM, and carrying out resonance risk determination. According to the method, the interaction dynamic characteristics of the network building converter and the power grid under the influence of the virtual impedance can be accurately represented, and the resonance risk of the grid-connected system is evaluated.

The invention belongs to the field of new energy, and particularly discloses a direct-current bus voltage control method and system of a flywheel energy storage system. Comprising the following steps: if DC bus voltage is in a normal range, DC voltage forms a q-axis current reference signal after being adjusted by a PI controller, the q-axis current reference signal generates a q-axis voltage instruction signal after being adjusted by a current control loop PI, and a dq-axis voltage instruction value is generated through decoupling; if the current control loop slightly deviates from the normal range, parameters of a PI controller are adjusted, so that an integration link plays a leading role in control output, a virtual impedance link connected to the current control loop in parallel is adjusted, and a dq-axis voltage instruction value is generated; and if the voltage is seriously deviated from the normal range, a grid-side power signal is fed forward to a machine-side direct-current voltage control loop, virtual resistance in a virtual impedance link is adjusted, and a dq-axis voltage instruction value is generated. According to the invention, the control mode is automatically switched according to different conditions of the DC bus voltage by adopting a threshold-grading regulation and control strategy, and the adaptability to large disturbance is improved while the steady-state precision of the system is maintained.

The invention is suitable for the technical field of power electronics and power transmission, and provides a low voltage ride-through control method and system for a network construction type converter, and the method comprises the steps: carrying out the conventional VSG control according to a VSG control strategy, and continuously monitoring the difference between the voltage of a power grid and a set reference value, so as to judge whether a fault occurs or not; when it is detected that the power grid breaks down, homodyne control is carried out on an active power control ring and a reactive power control ring of the grid-forming type converter so as to fix the phase and the amplitude of the output voltage of the converter; calculating and injecting a positive sequence compensation voltage and a negative sequence compensation voltage according to the drop degree of the power grid voltage; and according to the predicted impact current value, dynamically calculating and inputting adaptive virtual impedance. The power angle and the voltage in the fault period can be ensured to be stable, transient overcurrent is effectively restrained, and large power fluctuation is not caused.

The invention provides a network construction transient control method for a string type network construction type energy storage converter, which comprises the following steps of: identifying a power grid control instruction, and issuing a network construction operation control instruction and selecting a network construction type after judging a network construction requirement; in response to the networking operation control instruction, starting a thermal management system and executing a function screening control strategy; on the basis of the real-time electrical parameters and thermal parameters acquired by the information acquisition system, network construction over-temperature prediction is executed, and predicted junction temperature and predicted loss under the network construction working condition are obtained; according to the result of the network construction over-temperature prediction, whether network construction operation parameters need to be optimized is judged, if yes, a parameter optimization control instruction is generated, and if not, network construction function operation monitoring is started; and on the basis of the parameter optimization control instruction, virtual impedance is adjusted to reduce the output voltage and the output current of the converter so as to control the loss and the junction temperature, and the adjustment of the virtual impedance is calculated based on the difference value between the predicted junction temperature and the threshold junction temperature.

The invention relates to the technical field of distributed energy and micro-grids, in particular to a distributed energy output high-precision prediction model, which comprises the steps of collecting data and generating a power fluctuation probability envelope; constructing a complementary voltage-stabilizing virtual subgroup with a negative correlation compensation characteristic through a sequential sequence comparison algorithm; based on a power grid agent model and a kernel function SHAP algorithm, quantizing marginal contribution values of residual disturbance power of each subgroup to frequency deviation of the common connection point; performing a non-linear mapping on the contribution value to generate a virtual impedance correction parameter; and finally, through a layered decoupling closed-loop correction architecture, determining predicted power regulation and control vacancy and generating a compensation instruction. According to the method, the complementarity and the disturbance contribution of each heterogeneous power supply are quantified, so that the high-precision prediction of the distributed energy grid-connected stability influence is realized.

The invention discloses a VSG-based low-voltage ride-through hybrid control method for a network-building converter. The method comprises the following steps: acquiring grid-connected point voltage and output current of a grid-forming converter in real time, and judging whether to enter a low-voltage ride-through state according to a grid voltage drop degree; in the initial stage of a fault, a current reference saturation mode is adopted to quickly limit the output current of the converter so as to prevent a power device from being damaged by overcurrent; in the fault duration stage, a dynamic self-adaptive virtual impedance and reactive power reference coordinated regulation mechanism is introduced, so that the converter gradually recovers the reactive power injection capability while limiting the fault current, thereby realizing effective support for the grid-connected point voltage; when the voltage of the power grid drops seriously, the capacity of the inverter can be reserved for the reactive power support by temporarily reducing the output of the active power. According to the method, the current protection and voltage support requirements during the fault period are considered, and the operation stability and the power grid adaptive capacity of the grid-forming converter in the low voltage ride-through process are improved.

An inertia cooperative control method of an integrated optical storage alternating current and direct current hybrid micro-grid comprises the steps that firstly, according to static and dynamic power capacities of energy storage units in direct current sub-grids and allowed direct current voltage deviation, sub-grid equivalent virtual resistance and virtual capacitance are calculated; secondly, RC + R type parallel virtual impedance parameters are distributed according to the power proportion of each energy storage unit, and multi-energy-storage cooperative response power disturbance according to the capacity is achieved; then, a phase angle is generated based on the mapping relation between direct-current side voltage and frequency, an alternating-current voltage amplitude instruction is determined in combination with reactive power droop control and feeder impedance voltage drop compensation, and a dq-axis voltage instruction is generated through virtual impedance compensation; normalized three-phase modulation waves are obtained through voltage-current double closed-loop control and dq / abc coordinate transformation, and six paths of PWM signals are generated to drive an interconnection converter after the normalized three-phase modulation waves are compared with triangular carrier waves. The method does not need to depend on external communication, has the capabilities of autonomous inertia support, voltage and frequency coordinated regulation and reasonable multi-source power distribution, and improves the stability and dynamic response performance of the system under island operation.

The invention discloses a network construction converter virtual impedance and power reference cooperative adjustment method and system, and relates to the technical field of power control, a virtual synchronous generator system introduces virtual impedance to increase equivalent output impedance of an inverter, and an internal voltage reference generated by a virtual synchronous generator algorithm of the inverter is monitored in real time; monitoring the local voltage measured by the common coupling point in real time; based on the vector difference between the internal voltage reference and the local voltage, the accurate amplitude of the virtual impedance is solved in real time by combining the maximum current limit value of the power electronic device; and determining a function relationship between an active power reference value and reactive power based on the accurate amplitude of the virtual impedance, monitoring the reactive power measured at the common coupling point in real time, and adjusting the active power reference value according to the function relationship to keep a stable balance point. And virtual impedance is dynamically calculated to accurately limit current, and active power reference is adaptively adjusted according to real-time reactive response, so that maximized power grid support and safe and stable operation of the converter are realized.

The invention discloses a dynamic virtual impedance control method for multi-machine parallel connection of a network construction type energy storage converter, and belongs to the technical field of power electronics. The method aims to solve the problem that accurate reactive power distribution, circulating current suppression, dynamic response and voltage precision are difficult to consider in a multi-machine parallel system through fixed parameter virtual impedance. A dynamic adjustable virtual impedance module is introduced into the voltage outer loop output end of each converter, and virtual resistance and virtual inductance are calculated in real time based on locally measured output current, bus voltage change rate and adjacent machine reactive power deviation information; and the average reactive power of the system is estimated through a phase synchronization mechanism under the condition of no communication so as to realize multi-machine cooperation. According to the method, the reactive power distribution error is less than 5%, the bus voltage drop is less than 3%, the high-frequency circulating current is controlled within 5% of the rated current under all working conditions, and the dynamic performance and robustness of the system are remarkably improved.

The invention relates to the technical field of power systems, and particularly provides a network construction type energy storage wide and low frequency disturbance suppression method suitable for a weak power grid environment. The method comprises the following steps: constructing an equivalent impedance model, and analyzing RLC resonance impedance matching conditions; constructing a quantitative model of impedance dynamic correlation; designing a multi-parameter adaptive virtual impedance module; constructing a cooperative control architecture of the adaptive virtual impedance and the network construction type energy storage converter; through verification of a continuous voltage drop simulation scene, adaptive adjustment parameters are optimized by adopting indexes of oscillation amplitude attenuation rate and stabilization time so as to ensure a wide and low frequency disturbance suppression effect under a weak power grid, and according to the method, broadband oscillation suppression under the continuous voltage drop scene is realized through adaptive virtual impedance, and dynamic accurate compensation is realized.

The invention discloses a multi-loop anti-interference ride-through control system and method for a high-voltage three-level inverter, and is suitable for a three-phase T-type three-level grid-connected inverter. The system comprises a direct current side power supply circuit, an inversion main circuit, a filtering grid-connected circuit, a signal sampling and conditioning circuit, a multi-loop cooperative controller and a PWM driving and protecting circuit. According to the control method, a robust synchronous reference is provided through an outer ring virtual synchronous generator strategy; a middle ring adopts a virtual impedance model containing a high-frequency compensation item to selectively suppress switching noise; the inner ring adopts a quasi-proportional resonance controller to realize fundamental current zero-static-error tracking; the modulation layer dynamically optimizes a discontinuous pulse width modulation strategy based on a real-time EMI index; and the rings are switched to a low-voltage ride-through mode in cooperation when a fault occurs. On the premise of not increasing hardware, the anti-interference capability, the current quality and the ride-through stability of the inverter under the working conditions of strong electromagnetic interference and power grid drop are effectively improved.

The invention relates to the technical field of micro-grids, in particular to a direct-current component suppression method of a grid-connected inverter, the inverter and a storage medium. The direct-current component suppression method comprises the following steps: determining an expression of a direct-current component in grid-connected current according to a grid-connected inverter circuit model and a Kirchhoff's law; based on the expression of the direct-current component in the grid-connected current, virtual impedance capable of inhibiting the direct-current component in the grid-connected current is constructed; the virtual impedance is introduced into a control loop of the grid-connected inverter, and a calculation model of a modulation wave compensation item is obtained through equivalent transformation; and superposing the original modulation wave signal output by the current loop controller and the modulation wave compensation signal obtained based on the calculation model of the modulation wave compensation item to obtain a final modulation wave signal. According to the method, enhanced suppression is carried out on the direct current component by introducing the virtual impedance, the problem is solved from the source, the suppression effect is remarkable, and the alternating current fundamental wave performance is not affected.

The invention provides a network construction current limiting method, network construction type converter equipment and a new energy system, and relates to the technical field of new energy. The method comprises the following steps: in response to a condition that a power grid signal meets a preset condition, determining that network-forming converter equipment enters a current-limiting mode, and determining virtual impedance of a first stage of the current-limiting mode; determining that the network construction type converter equipment is in a first stage, and controlling the network construction type converter equipment by using the virtual impedance; and determining that the network construction type converter equipment is in a second stage of the current limiting mode, adjusting the virtual impedance according to the power grid signal, and controlling the network construction type converter equipment by using the adjusted virtual impedance. According to the embodiment of the invention, the current limiting mode of the network-forming converter equipment is divided into the first stage and the second stage, and the virtual impedance of the first stage is adjusted in the second stage, so that fault current limitation and power grid voltage support can be considered at the same time.

The invention discloses a self-adaptive current-limiting control method and related device for a network construction type energy storage converter under a symmetric fault of a power grid, and belongs to the technical field of network construction type energy storage converter control, and the method comprises the steps: constructing a corresponding fault current dynamic response model based on the network construction type energy storage converter under the symmetric fault of the power grid; generating a self-adaptive current-limiting control strategy based on the voltage drop depth of the power grid; wherein the self-adaptive current-limiting control strategy comprises the steps of carrying out overcurrent steady-state component suppression based on a phasor current-limiting method and carrying out overcurrent transient-state component suppression based on a virtual impedance control method, and self-adaptively adjusting a power instruction to meet a system support requirement in a current-limiting process; a fault current dynamic response model is solved through a self-adaptive current-limiting control strategy, a current-limiting control scheme is obtained, it can be ensured that the converter maintains the networking characteristic in the fault period, steady-state and transient overcurrent is effectively restrained, output current is strictly limited within a safety threshold value, and transient stability of a system is maintained.

The invention relates to the technical field of converter control, and provides a self-adaptive virtual impedance optimization method for a grid-forming type energy storage converter under a weak power grid, which comprises the following steps: injecting a multi-frequency-band collaborative disturbance signal into the power grid, acquiring a voltage response signal and a current response signal of the power grid, and carrying out online scanning and identifying the impedance characteristics of the power grid; establishing a power grid impedance model; constructing a real-time digital twinborn model synchronously operating with the physical converter, wherein the real-time digital twinborn model integrates the power grid impedance model and a multi-time scale state space model of the network-constructing type energy storage converter; and downloading the optimized virtual impedance parameter set to the physical networking type energy storage converter for execution, and performing closed-loop control of the adaptive virtual impedance. Therefore, the broadband stability and the dynamic performance of the network-forming type energy storage converter in the time-varying weak power grid environment are improved.

The invention relates to the technical field of electric power, and discloses a photovoltaic grid-connected system fault ride-through method based on VSG current limiting control. When it is detected that the PCC voltage is lower than a preset voltage threshold value, the photovoltaic inverter closes power outer loop control, an active current reference value and a reactive current reference value are reconstructed according to the voltage drop depth, it is guaranteed that grid-connected operation of the photovoltaic side is kept in the fault period, and voltage support is provided; a second-order rotor motion equation and an excitation control equation are established in an energy storage converter controller to simulate a synchronous generator, when PCC voltage drop or a power grid fault is detected, dynamically-adjusted virtual impedance is injected into the output end of a VSG according to the voltage drop depth so as to increase equivalent impedance and actively limit the peak value of short-circuit current, and the voltage drop or the power grid fault is detected. And switching the active power reference value into an active power reference value in a fault state and reducing or inhibiting active output, and switching the reactive power reference value into a reactive power reference value in the fault state so as to enhance the reactive power support capability of the energy storage system and maintain the voltage stability of the grid-connected point.

The invention discloses a distributed cooperative voltage control method for a hybrid flexible traction substation group, and aims at solving the problems of output voltage cooperation, no-load circulating current suppression and multi-substation load distribution during networking operation of a plurality of hybrid flexible traction substations (HFTSS). Rapid synchronization of output voltage phases of the substations is achieved by introducing an average consistency algorithm, and nearby distribution of train loads among the traction substations is achieved by combining self-adaptive virtual impedance. According to the method, the capacity of the hybrid flexible traction substation for coping with the dynamic change of the external power grid voltage phase can be effectively enhanced, the loss of a contact network is reduced, the regenerative braking energy utilization efficiency is improved, and a feasible path is provided for large-scale application of a low-cost hybrid flexible traction power supply system and improvement of a cooperative control technology system.

A VSG transient performance improvement method based on segmented power regulation and dynamic virtual impedance comprises the steps that a virtual impedance module capable of being put in and withdrawn is additionally arranged, and virtual impedance is put in rapidly when a fault occurs and withdrawn after the fault occurs; a rotor motion equation of the VSG is improved, and an adaptive adjustment coefficient is introduced to adjust an acceleration area and a deceleration area in each interval on a power angle characteristic curve; and based on an equal area criterion, performing segmented adjustment according to different intervals of the power angle in the transient process to obtain a final value of the adaptive adjustment coefficient. According to the method, through cooperation of dynamic virtual impedance and segmented active power adjustment introducing a virtual power correction coefficient, overcurrent is effectively suppressed in the voltage drop period of the power grid, and meanwhile, the power angle transient stability of the system is guaranteed.

The invention relates to a single-loop control method for a static synchronous phase modifier, which belongs to the technical field of power systems, and comprises the following steps of: comparing a maximum voltage difference value in three phases with a preset voltage threshold value to obtain a voltage difference value after amplitude limiting, and obtaining a first virtual reactance by using the voltage difference value after amplitude limiting and a preset current amplitude limiting threshold value; performing proportional integral control on the difference between the maximum current value in the three phases and the current amplitude limiting threshold to obtain a second virtual reactance; virtual impedance is calculated according to the first virtual reactance and the second virtual reactance; the product of the virtual impedance and the current of each phase is used as the current amplitude limiting voltage of the corresponding phase; the modulation wave of the corresponding phase is generated by using the internal potential and the current amplitude limiting voltage of each phase, so that the voltage single-loop control and the fault current amplitude limiting of the static synchronous phase modifier are realized, the broadband oscillation risk and the overcurrent risk of the converter are effectively reduced, and the safety and the reliability of static synchronous phase modifier equipment are improved.

The invention relates to the technical field of high-proportion new energy power systems, in particular to a method and system for calculating the short-circuit ratio of a network-following / network-constructing hybrid new energy power system, and the method comprises the steps: determining a network-constructing new energy access node, and deducing an impedance matrix of the network-following / network-constructing hybrid new energy power system; the system equivalent impedance calculation considering the virtual impedance control is used for considering the influence of the network construction type virtual impedance control on impedance characteristics; an improved new energy multi-station short-circuit ratio calculation model is given according to a traditional new energy multi-station short-circuit ratio simplification condition, the multi-station short-circuit ratio of any new energy node is calculated, and the influence rule of the access capacity, the connection reactance and the control characteristic of the network construction type new energy on the new energy multi-station short-circuit ratio of any node can be effectively evaluated; and the method can be further popularized and applied to strength calculation and influence law analysis of the power grid accessed by the converter with the network construction control characteristic.

The invention discloses a harmonic suppression and dynamic reactive compensation control method for an energy router, which is suitable for a micro-grid and a distributed energy access system. According to the method, three-phase current and voltage signals of an alternating current port of the energy router are collected, five-time and seven-time main harmonic components are extracted through fast Fourier transform, harmonic compensation current instructions equal in amplitude and opposite in phase are generated and injected into an inverter to be output, and active counteracting of main harmonics is achieved. Meanwhile, the bus voltage deviation and the change rate thereof are detected, a reactive current instruction is adjusted on line by adopting a fuzzy self-adaptive PI controller, rapid and smooth dynamic reactive compensation is realized, and the bus voltage is stabilized. Decoupling control of active / reactive and harmonic components is realized in combination with Park conversion, and virtual impedance is introduced to enhance system damping and harmonic suppression capabilities. Compared with the prior art, harmonic suppression and voltage support can be simultaneously realized under a single control framework, the response speed is high, the stability is high, and the method is suitable for high-performance grid-connected operation of the multi-port energy router.

The invention belongs to the field of power grid system control, and discloses a power grid system virtual impedance dynamic control method, system and device and a medium. The control method comprises the following steps: judging whether the power grid system breaks down or not by acquiring power characteristics of electronic equipment in the power grid system, including content proportions of voltage harmonics and current harmonics, current amplitude changes and positive and negative sequence voltage amplitudes. When a fault occurs, normal virtual impedance is calculated and combined with response current of harmonic waves to obtain dynamic virtual impedance, and then self-adaptive virtual impedance is comprehensively obtained and switched to the impedance value. According to the method, rapid and accurate dynamic current limiting and reactive power supporting under the complex fault working condition are achieved, the adaptability and stability of power electronic equipment to power grid faults are improved, fault current is effectively restrained, equipment damage is prevented, and meanwhile the transient characteristic and reliability of a system are enhanced.

The invention discloses a block chain technology and big data-based data synchronous scheduling management and control system, and relates to the technical field of data synchronous scheduling management and control. Comprising a cross-level dynamic observation module, a causal coherent decomposition module, an anti-fact playback construction module, a double-mirror-image time scale rearrangement module, a time-varying virtual impedance regulation and control module and a time reversal phase traction module. And the cross-level dynamic observation module constructs a cross-level cache link dynamic observation layer, collects cache pressure fluctuation data and link delay pulsation data of each node in the block chain network in real time, and generates a coupling feature baseline for representing a relationship between cache pressure and link delay. According to the invention, through multi-layer time sequence observation and time baseline correction, accurate control of cross-node data synchronization is realized, and repeated confirmation and account book bifurcation are prevented; and resonance energy is absorbed through the time-varying virtual impedance and the energy buffer zone, so that self-balancing and self-repairing of the system are realized, and global consistency and scheduling stability of the block chain are ensured.

The invention discloses a multi-energy complementary power distribution control method, belongs to the technical field of electric power system control, and aims to solve the problems that an existing multi-energy system control method based on periodic instruction issuing is heavy in communication burden, response lags when sudden disturbance is dealt with in two scheduling intervals, and the power distribution efficiency is poor. And the operation economy and the dynamic stability are difficult to consider at the same time. The method comprises the steps that an upper-layer optimization controller generates virtual impedance potential field function parameters and key topological characteristics and issues the virtual impedance potential field function parameters and the key topological characteristics to a local controller; the local controller executes power control based on the potential field gradient and monitors the topological position of the operation point; when a topology crossing event is detected, an asynchronous event triggering signal is sent upwards, and an upper-layer controller is triggered to carry out aperiodic re-planning. According to the method, decoupling of economic optimization and dynamic control is realized, the robustness and the adaptive capacity of the system under disturbance are improved, meanwhile, the communication burden is reduced, and the method is suitable for a system containing a large amount of distributed energy.

The invention discloses a power distribution area energy storage-photovoltaic oscillation cooperative suppression method based on impedance remodeling, and belongs to the technical field of power system stability control. According to the method, the impedance characteristic of the system is scanned online in real time, the virtual impedance controller parameters of the photovoltaic inverter are dynamically optimized, and the impedance frequency characteristic of the zone area network is actively remodeled, so that the zone area network is always far away from a stable critical point, and oscillation is prevented from occurring from the source. When it is detected that the oscillation energy exceeds the standard, the system immediately triggers the energy storage device to be switched to a virtual synchronous generator mode, phase information of a plurality of energy storage units in a fiber channel synchronization cluster is used, anti-phase damping current opposite to the oscillation trend is injected, and the oscillation energy is rapidly consumed. The invention provides a double-layer suppression strategy based on impedance remodeling and energy storage cooperation, the cooperation of photovoltaic impedance active prevention and energy storage instantaneous suppression is realized, the problem that a traditional fixed parameter damper loses efficacy due to frequency drift is solved, and the operation stability of a high-proportion renewable energy power distribution network is improved.

The invention discloses a virtual impedance compensation method for permanent magnet synchronous generator constant admittance modeling, and relates to the technical field of electromagnetic transient modeling of permanent magnet synchronous generators, and the method comprises the steps: firstly, carrying out the discretization of a permanent magnet synchronous generator model; secondly, decomposing the equivalent resistance matrix into a time-invariant part and a time-varying part; then, virtual impedance is added to the q axis of the generator model; thirdly, constructing a generator constant admittance model; thirdly, a converter accompanying discrete circuit model is integrated, a complete permanent magnet synchronous generator constant admittance model is formed, and a node admittance equation is established based on the Kirchhoff's current law; and finally, executing electromagnetic transient simulation. According to the method, constant admittance modeling is achieved based on virtual impedance compensation, the requirement for real-time inversion of a time-varying admittance matrix is eliminated, simulation calculation resource consumption is remarkably reduced, small errors are kept under various working conditions, and efficient simulation of a large-scale permanent magnet synchronous generator system is supported.

The invention relates to an improved network construction type energy storage converter control method and system, and the method comprises the following steps: constructing a conventional network construction type control framework containing P-f and Q-U control rings, and obtaining a basic control model; virtual impedance control including a virtual resistor Rv and a virtual inductor Lv is added in a voltage loop, and a primary improved control model is formed; then virtual capacitive reactance control of a virtual capacitor Cv is added in a current loop, and a final improved control model is obtained; and finally, controlling the converter through the model to realize stable support of the voltage and frequency of the power grid. Through cooperative improvement of voltage loop virtual impedance and current loop virtual capacitive reactance, the method and system can effectively improve the stability and robustness of the converter in a weak power grid environment, enhance the power grid supporting capability, solve the problem of easy instability caused by multi-loop coupling in traditional control, enable the converter to be closer to the external characteristics of a traditional synchronous generator, and improve the stability of the converter in a weak power grid environment. And the requirements of a new energy high-permeability power system are met.