266 results about "Virtual synchrony" patented technology

The invention relates to a virtual synchronous generator control method based on self-adapting moment inertia. The output of a grid-connected inverter in distributed generation is connected with an AC bus of a filter capacitor Cf which is in parallel connection with the grid-connected inverter through a filter inductor Lf; sampling is performed to obtain the output power, the voltage and the current of an output interface of an inverter; the output power, the voltage and the current are transmitted to a VSG (virtual synchronous generator) algorithm; the calculated terminal voltage of a VSG stator is sent to be controlled by a voltage external loop; the voltage external loop adopts a PI controller to stably load the voltage; the current of the filter capacitor is sent to be controlled by a voltage internal loop; the voltage internal loop adopts a PI controller to increase the response speed; a control signal is outputted by a voltage-current dual-closed loop to the grid-connected inverter; the moment inertia in the virtual synchronous generator in the control method can be changed in a self-adapted manner according to the change capacity of the system frequency. Through the adoption of the virtual synchronous generator control method disclosed by the invention, the transient state process of the system is reduced; a great deal of harmonic waves in the system is offset; the stability of frequency and the stability of voltage can be improved; the adaptability and the power supply quality of a micro-electrical network are improved; the problem that in a conventional method, the output frequency is reduced, is solved.

A fault inrush transient current restraining type virtual synchronous inverter and thereof is disclosed. The invention solves the problem that a virtual synchronous inverter will be burned due to inrush transient current in an extreme situation of a symmetrical fault occurring on the grid side by setting an information collection module for inverter output voltages and currents, a virtual synchronous inverting control module, a fault detection and synthesize module, a hysteresis comparison control module and a post fault clearing switch back grid-tie control module.

This invention discloses a system and method to operate a doubly-fed induction generator (DFIG) as a grid-friendly virtual synchronous generator (VSG). It comprises a DFIG modeled as a virtual differential gear that links a rotor shaft driven by a prime mover, a virtual stator shaft coupled with a virtual synchronous generator G and a virtual slip shaft coupled with a virtual synchronous motor M, and a variable frequency drive that behaves as a virtual synchronous motor-generator set to regulate the speed of the virtual synchronous motor M so that the speed of the virtual stator shaft, i.e., the speed of the virtual synchronous generator G, is within a narrow band around the grid frequency even when the rotor shah: speed changes. As a result, a grid-connected DFIG can be controlled to behave like a virtual synchronous generator without using a PLL.

The invention discloses an unbalance voltage compensation and control method based on a virtual synchronous machine. According to the method, the power calculating method on the basis of notch filter is adopted, the problems that a first order low pass filter is low in responding speed and stability and cannot eliminate secondary harmonic caused by unbalance load can be eliminated, the calculated total active power and reactive power serves as the feedback input of droop control, and part of produced unbalance voltage is suppressed by the proportional integral and the resonance control method; meanwhile, an unbalance voltage compensation controller is adopted to eliminate the unbalance quantity. The unbalance voltage can be compensated, the fine equalizing current balance of parallelly-connected multiple machines can be maintained, the method can be widely applied to micro grid inverter control on the unbalance loaded condition so as to maintain the output voltage balance during off-grid operation, and parallelly-connected operation of multiple machines is allowed.

The invention discloses a multiprocessor System and synchronous engine device thereof. the synchronous engine includes: a plurality of storage queues, wherein one of the queues stores all synchronization primitives from one of the processors; a plurality of scheduling modules, selecting the synchronization primitives for execution from the plurality of storage queues and then according to the type of the synchronization primitive transmitting the selected synchronization primitives to corresponding processing modules for processing, scheduling modules corresponding in a one-to-one relationship with the storage queues; a plurality of processing modules, receiving the transmitted synchronization primitives to execute different functions; a virtual synchronous memory structure module, using small memory space and mapping main memory spaces of all processors into a synchronization memory structure to realize the function of all synchronization primitives through a control logic; a main memory port, communicating with virtual synchronous memory structure module to read and write the main memory of all processors, and initiate an interrupt request to processors; a configuration register, storing various configuration information required by processing modules.

The invention discloses an overrunning virtual synchronous generator (VSG+) method with rotary inertia and damping self-optimization-trending. The method comprises the following steps: step one, a mechanical equation and an electromagnetic equation of a virtual synchronous generator (VSG) are established; step two, the rotary inertia J and damping D in a VSG model are increased as |delta f| is increased, wherein delta f is an absolute value of a difference between a power network rated frequency and the actual frequency of the VSG; and step three, according to self-adjustment of the rotary inertia J and the damping D, closed-loop control is performed on the |delta f|, and finally, grid connection of a distributed photovoltaic power generation system is realized. According to the VSG+ method with the rotary inertia and damping self-optimization-trending, provided by the invention, the rotary inertia J and the damping D in the VSG are adaptively adjusted as the |delta f| changes, the rotary inertia J and the damping D after adjustment then perform feedback regulation on the |delta f|, and finally, zero impact during grid connection of photovoltaic inverters is realized, such that the acceptance capability of a power network for the distributed photovoltaic power generation system is improved.

The invention discloses a grid connection method of an MMC-type light direct-current power transmission system. A virtual synchronization control method is combined with an MMC so that switching of operation modes of the MMC-type light direct-current power transmission system can be carried out, a special synchronization control circuit is needless, the system can be automatically synchronized with a power grid before grid connection, pre-synchronization time is short, the system can accurately follow frequency of the power grid after grid connection, and friendly grid connection is achieved.

The invention discloses a voltage control type virtual synchronizing method of a double-feed wind power generator set. Through simulating inertia and a frequency-modulating and voltage-modulating characteristic of a synchronizer, the set can be different from a characteristic of no electric grid frequency change response in a traditional current control type, thereby possessing capability of supporting voltage and frequency of a weak power grid based on the voltage control type through virtual inertia. The method provides and realizes a VCT-DFIC virtual synchronous control structure of which an inner ring is controlled by an improved double-feed generator stator voltage rotor current double-closed-loop structure based on adaptive stator virtual impedance and transmission line sag voltage feedforward compensation in a control manner which includes crossed control between stator voltage and rotor current and furthermore an outer ring is controlled by a virtual synchronous realizing algorithm. The method realizes output power control in VCT-DFIG grid integration operation in a weak grid condition with any actual impedance and effective decoupling, and furthermore a designed control structure realizes higher inertia and frequency supporting capability of the double-feed generator.

The invention discloses a method, a device and a system for controlling photovoltaic grid connection on the basis of a virtual synchronous machine. A photovoltaic grid connection system on the basis of the virtual synchronous machine comprises a photovoltaic cell panel, a DC / DC converter and a DC / AC inverter. The photovoltaic cell panel is connected with direct-current bus, one end of the DC / DC converter is connected with the direct-current bus, the other end of the DC / DC converter is connected with an energy storage cell, the direct-current bus is connected with a direct-current side of the DC / AC inverter, and an alternating-current side of the DC / AC inverter is connected into a transformer. The method, the device and the system have the advantage that the problem that an existing photovoltaic grid connection system is incapable of simultaneously controlling photovoltaic array terminal voltages and implementing functions of an existing virtual synchronous machine can be solved by the aid of the method.

The invention discloses a control method for a virtual synchronous generator capable of being adapted to imbalanced power grid and load conditions. The control method comprises the following steps that 1) an active ring simulates the mechanical characteristics of a speed controller and a rotor to obtain an output positive sequence voltage frequency and a phase position instruction; 2) a reactive ring simulates a n excitation controller to obtain an output positive sequence voltage amplitude value instruction; 3) a voltage-control and virtual synchronous impedance ring simulates the electrical characteristics of a stator; 4) positive and negative sequence current rings carry out accurate tracking on the positive and negative sequence current instructions respectively, and eliminates the negative sequence current output; and 5) a modulation signal is obtained by the combination of the positive and negative sequence current rings, and then the modulation signal is subjected to PWM to obtain a switching signal. Compared with the prior art, the output active power fluctuation and frequency fluctuation caused by imbalance of the power grid can be eliminated; and in addition, it is ensured that the output current of the virtual synchronous generator is balanced constantly, so that overhigh electrical stress of a certain bridge arm of the inverter can be avoided.

The invention discloses a virtual impedance voltage converter-based control method of a virtual synchronous motor. Output voltage and current of a voltage converter is controlled to have the characteristic of a synchronous motor through electric and mechanical main parts of the virtual synchronous motor, wherein the electric part comprises a novel virtual impedance simulation algorithm, a conventional converter current inner ring and a modulation strategy and the mechanical part comprises a power calculating module, a rotor mechanical equation and a virtual damping module. The virtual impedance voltage converter-based control method of the virtual synchronous motor can be used for simulating winding impedance without introducing a differential term of current output by the converter, so that the influence on impedance simulation by an extra low pass filter is overcome, and the current inner ring control of a parallel converter is not sacrificed, and therefore, alternating current is controlled, and the converter has the capacity of preventing current fluctuation, overcurrent and even impact without quick current inner ring control. A silent pole motor and a non-salient pole motor can be simultaneously simulated.

The invention discloses a current compensation based power decoupling method of a virtual synchronous power generator. The power decoupling method comprises the following steps of 1) acquiring a dq component of an output current of a virtual synchronous motor through sampling, acquiring power angle information by a mechanical property simulation part, and further calculating reactive power-power angle decoupling current compensation instruction; 2) acquiring transient state variable quantity of a virtual excitation electromotive force, and calculating active power-voltage decoupling current compensation instruction by combining the dq component, obtained in the step 1), of the output current; and 3) correcting the reactive power-power angle decoupling current compensation instruction obtained in the step 1) and the active power-voltage decoupling current compensation instruction obtained in the step 2) to obtain a new current instruction, and obtaining a switching signal through a current ring to drive a switching network. The invention proposes the power decoupling method applicable to the virtual synchronous motor, and the influence of a power angle on droop control can be eliminated; and compared with the prior art, the power decoupling method has the advantages that dynamic power oscillation and a steady-state error brought by power coupling can be eliminated.

The invention discloses a fault protection and ride-through control system and method for a virtual synchronous machine. The fault protection and ride-through control method for the virtual synchronous machine comprises the following steps of measuring the three-phase voltage and current on the inverter output side, and calculating the active power according to an instantaneous power theory; if an asymmetric voltage drop fault occurs, extracting the voltage positive sequence component of the power grid to obtain a switching signal, and calculating the correction amount when the active power and the reactive power need to be output; if the voltage drop depth of the power grid exceeds a preset value, obtaining a supporting voltage through a power system stabilizer; and performing calculation and regulation through an active equation, a reactive equation, a torque inertia equation, and an electromagnetic torque equation to obtain the amplitude value and the phase angle setting value of the output voltage, and performing PWM modulation. According to the fault protection and ride-through control system and method, an energy storage unit is adopted for performing voltage-stabilizing control; and the direct bus voltage is stabilized while it is ensured that overcurrent does not occur, so that huge voltage fluctuation is avoided, and the performance degradation of the system is prevented.

The invention relates to a method for changing a group key GK for a secure data exchange in a group of network elements P1 . . . Pn (n=2, 3, . . . ) in a network system having a closed peer-to-peer configuration and a virtual synchronism supporting group communication protocol in a communication layer of a system architecture of the network system, wherein in the case of a change in a composition of the group of network elements P1 . . . Pn, caused by the join of a new network element Pn+1 into the group of network elements P1 . . . Pn or by the leave of a network element Pv (1≦v≦n) from the group of network elements P1 . . . Pn, a group key renewal, in which a network element Pi* (1≦i≦n) selected from the group of network elements P1 . . . Pn generates a new group key GKneu, is carried out and the new group key GKneu is transferred from the selected network element Pi to all the remaining network elements Pk (1≦k≦n, k≠i) of the group of network elements P1 . . . Pn in the changed composition, which the selected network element Pi* achieves by carrying out a key exchange with all the remaining network elements Pk in accordance with the Diffie-Hellman principle in order to transfer the new group key GKneu.

The invention provides an augmented reality-based virtual synchronization display method and system. The method comprises the steps of: S1, acquiring first feature point information in a preset reality scene image and inputting the first feature point information into a simultaneous localization and mapping module to create a three-dimensional virtual scene; S2, performing movement tracking on a user and obtaining first movement state information in the reality scene of the user; S3, setting second movement state information in the reality scene of all virtual models, except for a first client virtual model corresponding to a first client, in the three-dimensional virtual scene; S4, displaying all the virtual models, except for the first client virtual model, in the three-dimensional virtual scene in the reality scene; S5, synchronizing the first movement state information and the second movement state information to a plurality of clients. The SLAM technology-based movement tracking and three-dimensional virtual scene modeling reinforce the interaction between players and virtual objects in the real world and improve the user experience effect.

The invention discloses a self-adaption output impedance control method based on a virtual synchronous machine. The self-adaption output impedance control method firstly discloses a steady-state output impedance controller to improve the steady-state output impedance to guarantee paralleled current sharing in parallel steady operation, then provides a capacitance and voltage compound differential controller to improve damping of a system and enhance the stability of the system and finally adopts a dynamic output impedance controller to reduce output impedance in a dynamic process and voltage jump to improve dynamic response of output voltage. The self-adaption output impedance control method can be widely applied to control on micro grid inverters in different load conditions and meets the requirement of the dynamic-steady-state performance in off-grid operation of the micro grid inverters. Furthermore, parallel-connection operation of a plurality of inverters is achieved.

The invention provides a control method and a device for connecting wind power to a flexible HVDC transmission system. Firstly, the actual frequency of an AC grid at a receiving end, the actual frequency of an AC bus bar at a wind farm side, the actual voltage at a DC side of a receiving end converter station are obtained, and the reference voltage at the DC side of the receiving end converter station is determined. Then, the voltage of DC line, the frequency of AC bus and the active power of wind farm are controlled separately, which has high reliability, short frequency modulation response time and good frequency modulation effect. Virtual synchronous machine droop control is adopted in the sending-end converter station, which improves the response speed of frequency regulation and shortens the time of frequency modulation. The frequency of the alternating current bus on the wind farm side is controlled by fixed frequency control or frequency conversion control, The active power of wind farm is controlled by virtual inertia, which makes the increased or decreased power released or supplemented in time when the flexible HVDC system provides frequency modulation for the receiving AC network, and reduces the risk of HVDC line voltage exceeding the limit, and greatly improves the reliability of HVDC system.

This invention discloses a controller and method to reconfigure the inertia, damping and fault ride-through capability of a virtual synchronous machine (VSM). The virtual inertia is reconfigured via adding a low-pass filter to the torque (equivalently, active power) signal of the VSM and the virtual damping is reconfigured via adding a virtual damper between the VSM voltage and the output voltage sent to the PWM conversion, instead of adjusting the inertia and the damping in the swing equation. The function of the virtual damper is to scale the existing converter-side inductance or to insert the desired inductance into the VSM, which increases the damping. Moreover, the fault ride-through capability of the VSM can be reconfigured to achieve the given fault-current level via reconfiguring the damping and the inertia properly.

The invention relates to a two-parameter adaptive control method for a virtual synchronous generator. The method is used for enhancing the stability of microgrids to access to electric power systems.The method includes performing automatic adjusting on control parameters according to the changes of power angle characteristics and natural oscillation angular frequencies and the frequency power angle relation of a virtual synchronous generator, wherein the control parameters include virtual inertia and damping coefficients; and when the natural oscillation angular frequencies deviate power gridfrequencies, increasing the virtual inertia and damping coefficients, and reducing the virtual inertia and damping coefficients when the natural oscillation angular frequencies close to the power grid frequencies. Compared with the prior art, the method has advantages.

The invention discloses an inverter control device and method based on network voltage phase locking and a virtual synchronous machine. At an initial work stage of an inverter, the inverter adopts a conventional inverter control scheme based on network voltage phase locking to complete grid connection work; after grid connection work of the inverter is stable, the inverter adopts a virtual synchronous machine control scheme. After grid connection of the inverter is realized through a conventional grid connection control scheme based on network voltage phase locking, a virtual synchronous machine control policy and a traditional conventional grid connection control scheme are entirely switched, thus, the grid-connected inverter is integrated with the virtual synchronous machine, and a pre-synchronization control link and corresponding terminal voltage detection points in the process from grid separation to grid connection of the inverter under the virtual synchronous machine control scheme are omitted, and a significant technological base is provided for an inverter control scheme applied to the distributed power generation and micro-grid field. Moreover, an inverter system keeps stable, safe and reliable operation from beginning to end in the switching process of the two control modes.

The invention discloses a transient control method for controlling the synchronous stability of a virtual synchronous control inverter. At present, the research on the stability of an inverter mainly focuses on the small-disturbance stability of an inverter in a micro grid. There is relatively less research on the transient stability under large disturbance, and the stability mechanism is unclear. In view of the virtual power angle instability caused by inverter current saturation, reactive power plus transient control are introduced into virtual synchronous control, so that an inverter has a reachable stable equilibrium point in the transient process of current saturation, and the synchronous stability of the inverter under large disturbance is ensured. The technical problem that there may be no stable equilibrium point in the transient process for the system due to saturation of the inner current loop of an inverter is solved. Transient instability of virtual power angle after an inverter goes to a current source mode is prevented.

The invention discloses a photovoltaic power generation system virtual synchronous machine control method, control device, converter and system. The direct current side, connected with a photovoltaicmodule, of a photovoltaic inverter is connected to energy storage equipment and an energy storage converter; the voltage and current of the photovoltaic module are collected, a maximum power point tracking algorithm is carried out, a direct current voltage target value is obtained, and the energy storage converter is controlled to operate in a constant output direct current voltage mode accordingto the direct current voltage target value; direct current power output by the photovoltaic module is multiplied by the conversion efficiency of the photovoltaic inverter, the SOC optimal regulation power components of the energy storage equipment are superposed as an active power command of the photovoltaic inverter, and the photovoltaic inverter is controlled to operate in a virtual synchronousmachine mode according to the active power command. The application requirement can be met just by needing relatively small battery capacity, so that the maximum power generation capacity of a photovoltaic panel is guaranteed, the available rate and service life of the battery are optimized, and simultaneously, power support is provided for a power grid.

A transfer press machine which can accurately and promptly check interference and can be easily handled is provided. The transfer press machine includes an interference check device including: a data-conversion constituent element storage section which stores a press-side data-conversion constituent element and a transfer-side data-conversion constituent element in a state of being placed in virtual space to have the same relative positional relationship as in real space; a virtual press operation control section which causes the press-side data-conversion constituent element to perform a virtual press operation in the virtual space according to a press motion; a virtual transfer operation control section which causes the transfer-side data-conversion constituent element to perform a virtual transfer operation in the virtual space according to a transfer motion; a virtual synchronization timing information generation-output section which generates and outputs virtual synchronization timing information, and a virtual interference determination section which determines whether or not interference occurs between the press-side data-conversion constituent element and the transfer-side data-conversion constituent element during a transfer press cycle.

The invention relates to a virtual synchronous control method and device for island double-fed wind power plant high-voltage direct current grid connection. The method comprises the following steps: configuring a direct current power supply for a direct current bus of a DFIG wind turbine generator back-to-back converter, and adopting a vector control method of fixed alternating voltage to providestarting power supply for black starting of a high-voltage direct current system; using VSG into the control for grid connection and normal operation of a DFIG wind turbine generator, after the VSG realizes reactive voltage droop control through a rotor side converter, wherein a grid-side converter can be flexibly switched into unit power factor control, and simultaneously the direct current powersupply exits; adopting frequency regulation and correction control method, and realizing system sending end bus frequency stabilization and active balance by a rectifier; adopting batched successivestarting in the whole wind power plant, and thus realizing virtual synchronous control for island DFIG type wind power plant high-voltage direct current grid connection. The power loss and construction cost can be reduced, the stability is improved, and the method can be applied in the high-voltage direct current grid connection field of new energy resources.

The invention belongs to the field of virtual synchronous motor control and particularly relates to a virtual synchronous generator control method based on droop coefficient adaptive adjustment. The problem that electrical equipment is sensitive to the change of a frequency and a voltage amplitude, and a VSG can maintain the balance of the microgrid power facing the change of a microgrid load in an off-grid operation mode, and the no-deviating regulation of the frequency and the Small deviation of phase voltage amplitude adjustment are achieved.

The invention discloses a fuzzy-control-based virtual synchronous motor's virtual inertia adaptive regulation method and a frequency control method. The method comprises the following steps: targeted to the micro source of a currently available micro power grid utilizing the virtual synchronous motor control technology for inversion output, using the output frequency error and the error variation rate of the micro source as the fuzzy output; and based on a two-dimensional fuzzy principle, dynamically adjusting the virtual inertia time constant. The invention further provides a frequency control method, comprising: in combination of the mechanical equation of a virtual synchronous motor, adjusting the output frequency of the virtual synchronous motor to strike a balance between the frequency support and dynamic response in its involvement in the concrete frequency adjusting process, to reduce load switching and the frequency fluctuation rising from micro source grid connecting and to ensure the stable frequency and rapid response of the micro power grid under the islanding state.

The invention provides a method for conducting virtual simulation on a breaker assembly robot. The method comprises the steps that relevant information of a breaker assembly production line is collected to be guided into preset model software, a physical model of the breaker assembly production line is built, and the assembly time and sequences of all components are determined; according to assembly information, logical models of all mechanical assembly devices in breaker assembly are designed based on a Petri network; a mechanical arm three-dimensional model, adapting to the breaker assemblyinformation, of the assembly robot is built, and motion parameters of mechanical arms are calculated to build a motion model; and the motion parameters are subjected to motion simulation, reasonability of model parameters is ensured, and finally a breaker assembly model and the mechanical arm model are introduced into a unity3d scene to achieve virtual motion of the breaker assembly robot. According to the method, the motion parameters of the mechanical arms are solved based on inverse kinematics, through the Petri network, the logical relationship is built, and a virtual assembly system is built for motion simulation of the breaker assembly robot to achieve synchronous-interaction-type display of reality and virtuality.

The invention discloses a control structure and method for a virtual synchronous machine of a voltage source converter based high voltage direct current (VSC-HVDC) system. The control structure comprises a VSC virtual synchronous machine, wherein the VSC virtual synchronous machine is connected with a power grid through a grid-connected gateway KS. The control system of the control structure comprises an active power regulation module, a reactive power regulation module, a mechanical module and an electrical module. By inertia and impedance characteristics of a VSC simulation synchronous power generator and functions of frequency regulation and voltage regulation, the stability of an AC power system is improved, and seamless switching of grid-connected and island modes is achieved. The method comprises a DC voltage control method and an active power control method, can be used for all VSC applications in the VSC-HVDC system and has the function of coordinated control on a DC voltage, and the running reliability of a DC system is improved.

The invention relates to a control method of a microgrid bidirectional converter based on a virtual synchronous machine and stability analysis thereof. An integrator is added in a damping link of a rotor motion equation, and an angular frequency deviation value is fed back and compensated, so that the error-free control of alternating current subnet frequency in a microgrid off-grid mode is achieved. In consideration of the bidirectional transmission characteristic of the converter, a control target is switched into a direct-current voltage from an alternating-current frequency in real time bychanging a virtual mechanical active power reference value given mode, and stable control of direct-current bus voltage is achieved. By establishing a power inner ring and a voltage / frequency outer ring small signal model, transfer functions of the converter in a frequency control mode and a direct current voltage control mode are respectively solved, and stability analysis is performed. The control method of the microgrid bidirectional converter based on a virtual synchronous machine and the stability analysis thereof can well achieve the frequency error-free adjustment of the frequency andthe stable control of the direct current voltage under the off-grid mode.

The invention discloses a method for improving the stability of a virtual synchronous machine grid-connected inverter system with the consideration of sampling delay. The method comprises the steps: establishing a small signal state space model of a VSG grid-connected inverter system; analyzing the structure of the VSG grid-connected inverter system, and determining the position of a delay link; determining a small signal state space equation of each link in the VSG grid-connected inverter system; establishing a small signal state space delay correction model of the VSG grid-connected invertersystem according to the small signal state space model of the VSG grid-connected inverter system and the small signal state space equation of each link of the VSG grid-connected inverter system; on the basis of the delay correction model, analyzing the stability of the VSG grid-connected inverter system, and determining a control parameter value range capable of enabling the VSG grid-connected inverter system to stably operate, thereby improving the stability of the VSG grid-connected inverter system. The problem that an existing VSG model is not accurate enough is solved, and the problem that the stability of the VSG grid-connected inverter system is not high due to the fact that the stability of the VSG grid-connected inverter system is analyzed on the basis of an ideal VSG model is solved.