232 results about "Off-the-grid" patented technology

The invention provides an on / off-grid control method for a microgrid with a plurality of distributed power supplies. When the microgrid is on on-grid operation, a central controller of the microgrid can continuously carry out isolated island detection. When the microgrid is detected to be in an isolated island operation state, isolated island operation control is carried out according to a preset strategy. When the microgrid is in an off-grid operation state, the central controller of the microgrid can start an on-grid process to achieve the positive sequence voltage amplitude of the large power grid side, the frequency of the large power grid side, the frequency of the microgrid side, the voltage of the large power grid side, the voltage of the microgrid side, the voltage phase angle value of the large power grid side and the voltage phase angle value of the microgrid side. Whether the microgrid is suitable for on-grid operation is judged by comparing the relationship between correlation values and preset values. If on yes judgment, the central controller of the microgrid can control the breakers to be switched on to achieve grid connection. The control method can achieve the on / off-grid control on the microgrid with distributed power supplies, avoids long-time off-grid operation of the mcirogrid and can timely break the mcirogrid to enable the microgrid to operate normally when a larger power grid is broken down.

The invention relates to solar photovoltaic generating applications, and in particular relates to a multi-mode photovoltaic generating system, wherein the multi-mode photovoltaic generating system mainly adopts off-grid power generation, and can release gird-connected power generation as for the surplus electric energy which is not consumed completely by a DC (direct-current) emergency load and storage batteries. The system comprises a controller, solar-cell arrays, a storage battery, the DC emergency load, a grid-connected inverter and a public distribution network, wherein a part of DC electric energy output by the solar-cell arrays is supplied for the DC emergency load by a DC bus, and the other part of the DC electric energy output by the solar-cell arrays is stored in the storage batteries. When the voltage of the DC bus is out of the normal range, the storage batteries supply the energy for the DC emergency load by a charge-discharge controller; and when the storage batteries finish the charging and the voltage of the DC bus is within the normal range, the surplus DC electric energy can be converted into AC (alternating-current) electric energy by a DC boost converter and a grid-connected inverter and then the AC electric energy is transmitted to the public distribution network. The system provided by the invention can improve the efficiency and the time of annual power generation of the system, and has good application prospects.

A single phase grid correction system for correcting the power factor of an electrical power grid. The grid has a generator, transmission lines connecting the generator to distribution nodes, feeder lines radiating from each node, and groups of consumers connected to each feeder line. A capacitor bank is located at a number of consumer's premises, indoors, either beside or forming part of the consumer's normal single phase electric panel. A set of remotely controlled switches at the consumer's premises permits the capacitor banks to be switched in and out of grid connection and also allows non-essential high energy consuming loads, not necessarily inductive, to be switched on and off the grid. The grid correction systemic are widely distributed at consumer's premises throughout the grid. By remotely controlling the switches, the utility operator can switch capacitor banks at selected consumer premises in or out of the grid to provide or remove reactive power as needed, and can also selectively remove load from the grid to reduce the likelihood of sudden uncontrollable load shedding.

The invention relates to a method for controlling energy storage converters in a large-scale off-grid micro-grid. The method includes the steps of firstly, setting up the large-scale off-grid micro-grid; secondly, conducting primary frequency modulation on the off-grid micro-grid by means of an energy storage power station through a Droop work mode; thirdly, conducting secondary frequency modulation on the off-grid micro-grid; fourthly, conducting thrice frequency modulation on the off-grid micro-grid through a micro-grid energy management module; fifthly, conducting master and slave control on the multiple energy storage converters in the energy storage power station. According to the method, by means of flexible control over the energy storage converters, the problem of reliable power supply for independent power supply systems in remote electricity-free areas or island grids or other areas can be effectively solved, and the power supply systems can independently run in a safe, stable and economical mode. The method is applied to the multi-energy complementation alternating current bus shared type off-grid micro-grid, the multi-machine parallel operation of the energy storage power station is achieved through high-speed master and slave communication in the energy storage power station, and safe, stable and economical running of the micro-grid is achieved through interstation peer-to-peer control of the energy storage power station.

The invention discloses a micro-grid modular energy storage device optimal configuration and control method. The method comprises the steps that 1) energy storage power is configured; 2) the capacity of an energy storage battery is calculated; 3) the energy storage battery is selected according to an actual energy storage battery type selection principle; 4) during the operation of a micro-grid system, the charge-discharge state and the charge-discharge value of an energy storage system are established according to the output value of each distributed power supply and the conditions of the SOC and SOH of the energy storage battery; and 5) grid-connection and off-grid switching needs to be carried out, a seamless switching mode is used, and specifically off-grid to grid-connection, planned off-grid and unplanned off-grid are seamlessly switched. According to the invention, the method describes a whole set of solutions of an energy storage unit in the micro-grid, and has the characteristics of typicalness, operability and the like.

A system extracts power from a typical high voltage (200-500 vdc) grid tie solar system and deliver it to a low voltage (12-24 vdc) battery bank. This product parallel connects in between an existing grid tie solar array, and an existing grid tie inverter, transforming the voltage down, and acting as a charge controller, engaging and disengaging as necessary to keep the low voltage battery bank at a high state of charge. This system enables the grid tie PV array to have a second use as the energy source for a low DC voltage off grid system. This system, when combined with standard low DC voltage grid inter-active off grid inverter / charger, and a battery bank, forms a complete off grid system, while allowing the host grid tie system to function normally when the grid is on.

The invention discloses a static switch and a control method applied to a connection of a microgrid and a public supply network. The static switch and the control method applied to the connection of the microgrid and the public supply network are characterized by comprising a main circuit and a controller, wherein the main circuit is placed between the public supply network and the microgrid, the controller controls the main circuit to turn on and turn off, and on-grid and off-grid of the microgrid are achieved through the power on and power off of the main circuit. Voltage, frequency and phase position of the public supply network and the microgrid and currents flowing past a bypass circuit are sampled by the controller to acquire a sampling signal, the power on or power off of the instruct main circuit are judged to achieve the on-grid and off-grid of the microgrid through calculation. According to the static switch and the control method applied to the connection of the microgrid and the public supply network, full automatic control on the smooth on-grid and off-grid of the microgrid is achieved, a micro source inverter of the microgrid can be monitored and controlled by the controller, and the purpose of energy management of the microgrid or assisting an upper level device to achieve energy management of the microgrid is achieved.

Housing for emergencies or for those in need could be a short-term solution or may be set up as a longer-term shelter. The shelter may be flexible to grow and change enough to accommodate the individual, the family and the community. The shelter is more substantial than a tent and easier to assemble and transport as compared to conventional shelters. The shelter can be transported in a standard size truck bed (for example, 4 feet by 8 feet) and erected by two individuals in a minimal amount of time, typically less than an hour. The walls of the shelter may include various features, including shelving, bathing facilities, sinks, beds, lighting, and the like. The shelters may be designed to be connected to external electric and water supplies. Optionally, the shelters may be designed as stand-alone, “off-the-grid” units. The ceiling of the shelter may include one or more solar panels to provide power for the shelter. The shelter's container provides the essentials needed to sustain life. This takes away the need for standing in multiple lines and gives the much needed immediate help.

The invention relates to an FFS-type TFT-LCD array base plate structure and a manufacturing method thereof. The array base plate structure includes a glass base plate, a grid electrode formed on the glass base plate, a grid line, a common electrode line and a transparent electrode, a grid insulating layer formed on the glass base plate, an active layer and a source-drain electrode layer sequentially formed on the glass base plate and arranged above the grid electrode, a passivation layer formed on the glass base plate, a via hole formed on the passivation layer, a blocking channel formed on the passivation layer and used for blocking off the grid line and the common electrode line, and a pixel electrode formed on the passivation layer and connected with the drain electrode in the source-drain electrode layer through the via hole. Through adding the blocking channel into the arranged base plate, the invention can efficiently repair the badness caused by the grid line residual and the common electrode residual. The invention introduces the repair concept into the process of designing a mask plate, and has good effect on repairing the badness caused by the grid line residual and the common electrode residual, etc.

The invention relates to a repairing method of a liquid crystal display device. The liquid crystal display device is provided with an array base plate. The array base plate comprises a plurality of grid lines, a plurality of data lines vertically crossed with the grid lines, a plurality of pixel electrodes and a plurality of thin film transistors. The grid electrodes, the source electrodes and the drain electrodes of all the thin film transistors are respectively and electrically connected with the corresponding grid lines, the data lines and the pixel electrodes; when one electrical connection defect exists on the data lines, the repairing method comprises the following steps: cutting off one side of the grid line crossed with the data line having electrical connection defects; cutting off the grid electrode of the thin film transistor correspondingly connected with the other side of the grid line into two parts, so that the source electrode and the drain electrode of the thin film transistor are divided into two parts which are not electrically connected; then respectively and electrically connecting the parts and the other parts of the source electrode and the drain electrode of the thin film transistor; and electrically connecting the data line and the grid line cut off. The repairing method can reduce the manufacturing cost of the liquid crystal display device.

Housing for emergencies or for those in need could be a short-term solution or may be set up as a longer-term shelter. The shelter may be flexible to grow and change enough to accommodate the individual, the family and the community. The shelter is more substantial than a tent and easier to assemble and transport as compared to conventional shelters. The smaller of shelters can be transported in a standard size truck bed (for example, 8 feet by 12 feet) and erected by two individuals in a minimal amount of time, typically less than an hour. The shelter may include various features, including shelving, bathing facilities, sinks, beds, lighting, and the like. The design of the shelter is to be connected to external electric and water supplies. Optionally, the shelters may be designed as stand-alone, “off-the-grid” units. The ceiling of the shelter may include one or more solar panels to provide power for the shelter. The shelter's container provides the essentials needed to sustain life. This takes away the need for standing in multiple lines and gives the much-needed immediate help.

The embodiment of the invention discloses an IGBT (insulated gate bipolar translator) protection method and protection circuit and belongs to the technical field of electronic circuits, and the method and the circuit can be used for solving the problems of low accuracy of the IGBT short-circuit judgment and poor reliability of the IGBT in the prior art. The IGBT protection method comprises the following steps: reducing the grid voltage of the IGBT when voltage of an IGBT collector is higher than a preset first threshold voltage; and cutting off the grid voltage of the IGBT when the voltage of the IGBT collector is higher than a preset second threshold voltage. The IGBT protection circuit comprises a step-down circuit and a shut down circuit which are connected between the collector and the grid of the IGBT, wherein when the step-down circuit is used for reducing the grid voltage of the IGBT when the voltage of the IGBT collector is detected to be higher than the first threshold voltage; and the shutdown circuit is used for shutting down the grid voltage of the IGBT when the voltage of the IGBT collector is detected to be higher than the second threshold voltage. The IGBT protection method and the protection circuit are applied to control and protection of the IGBT.

The invention relates to an off-grid integrated energy system double-layer planning method. The method comprises the steps of: obtaining renewable energy typical day data, cold, heat and electric loadhistorical data, equipment parameters in an integrated energy system, operation parameters and operation conditions of the integrated energy system; constructing a mathematical model of each energy supply device in the comprehensive energy system; according to the structure of the comprehensive energy system, constructing the double-layer optimization model of the comprehensive energy system, enabling the upper-layer optimization model to plan the system equipment capacity with the minimum total cost of the off-grid integrated energy system as the target, and enabling the lower-layer optimization model to optimize the system operation state with the minimum system load shortage as the target; and solving the double-layer optimization model to obtain the optimal capacity configuration result of the integrated energy system. An electricity-to-gas conversion device is applied to off-grid integrated energy system planning, the electricity-gas coupling performance is improved, the system cost is reduced, and the economy of the system is improved.

The invention relates to a method for stably controlling switchover from micro-grid connection into an island state. When switchover is planned, a micro-grid stability control system collects grid connection point power before the micro-grid is sectionalized from an electric system, a power source and a load are configured to be basically balanced, and meanwhile the grid connection point transmission power before sectionalization is sent to an inverter; a grid connection point breaker is stably cut off, the output power of the inverter is maintained as the grid connection point transmission power before the sectionalization, and power can reach the balance immediately after the micro-grid becomes off-grid. When the switchover is not planned, the micro-grid is sectionalized with the electric system suddenly to form an island, the load or the partial power branch circuit is cut within 10ms according to the difference between currents before the sectionalization of a grid connection point and the maximum output power of an energy storing inverter, and the stability of the system switchover moment is ensured; the energy storing inverter with the maximum capacity is immediately transferred into V / F control, and other power sources are set to be P / Q control. According to the method, the micro-grid connection can be smoothly switched over to the island state.

The invention discloses a tunnel cross-section primary lining construction process. The tunnel cross-section primary lining construction process includes steps of S1, chiseling away the lower portionsof middle partition walls according to 6m sections, inverting primary supporting concrete in secondary lining thickness ranges, cutting off the lower portions of grid main reinforcements and formingfilling portions; S2, laying waterproof layers, binding reinforcing steel bars, pouring inverted arch concrete, pouring the filling portions and forming inverted arches; S3, detaching two ends of eachmiddle partition plate in 1m ranges, detaching the primary supporting concrete in the ranges of the tops of the middle partition walls and cutting off the grid main reinforcements; S4, erecting transverse formwork supports, mounting arch centers and formworks, pouring side wall and arch concrete and forming second linings; S5, erecting temporary supports, detaching temporary remaining braces, sequentially breaking down and detaching the middle partition walls and the middle partition plates from top to bottom and from edge to center and completely detaching temporary supporting. The tunnel cross-section primary lining construction process has the advantages that the residue earth generation volumes at earlier stages can be effectively reduced, the influence degree of residue earth outwardtransport on the progress can be lowered, and secondary lining which is a critical working procedure can be constructed in an acceleration manner in advance.

The invention provides an off-grid double-fed wind power generation system and a maximum wind energy capture method thereof. The power generation system comprises a double-fed generator, a rotor side converter, a load side converter, a bidirectional DC / DC (direct current) converter, a load side variable-current controller, a rotor side variable-current controller, a DC / DC variable-current controller and the like. The load side variable-current controller adopted by the invention can calculate a stator current reference value required for realizing the maximum wind energy capture according to the wind turbine speed and a maximum power curve, input a deviation between the stator current reference value and a feedback value to a proportional integral controller, produce a control voltage of the load side converter and generate a space vector PWM (pulse width modulation) signal to drive a power switch device of the load side converter. The rotor side converter can control the stator voltage of the double-fed generator to maintain at a rated value, and the load side converter can control the stator output power of the double-fed generator, thus the problem that output voltage stabilization and maximum wind energy capture cannot be simultaneously realized in the existing off-grid double-fed wind power generation system can be solved, and the wind energy utilization rate and economic benefit of the generating system can be improved.

The invention discloses an inverter which comprises an inverter body, a remote contactor, an inverter output voltage sampler and a power grid voltage sampler. The inverter body comprises an inverter power unit and an inverter control unit, the remote contactor is arranged between an output end of the inverter body and a load or a power grid, the inverter output voltage sampler is arranged at the output end of the inverter body, and the power grid voltage sampler is arranged at a power grid end. The inverter control unit transmits grid-disconnection or grid-connection instructions to the inverter power unit and is further used for controlling connection or disconnection of the remote contactor between a distributed power generation system and the power grid. The inverter has the advantages that an independent operation mode or a grid-connection operation mode can be implemented, the two working modes can be switched over smoothly, the inverter brings convenience for interactively utilizing a distributed renewable energy source and the power grid, impact on the power grid is prevented, and the safety of the power grid is protected.

The invention relates to a method for automatically tracing communication network users, comprising the following concrete steps of: (1) generating the behavior characteristic information of users, wherein the information contains daily effective contact number information of the users; (2) tracing each user in Home Network, and identifying the effective contact number information of the users; when the user state generates abnormality, carrying out similarity calculation with the characteristic information of additional users of other operators; if the similarity reaches a preset threshold value, being identified to be the same user; the similarity is obtained by calculating the coincidence condition of the effective contact numbers of abnormal users of the Home Network and the effective contact numbers of the additional users of other operators; if the abnormal state of the user is off-net state, judging that the user is completely penetrated; and if the abnormal state of the user is the obvious fall of telephone traffic, representing that the user is in a penetration transition period.

The invention discloses a fuzzy decision method for an island micro-grid including a wind-solar-diesel-battery and seawater desalination system. Aiming at the problems that the operation state of a distributed power supply in an island micro-grid system generally has fluctuation, randomness and difficult predictability, and difficult matching exists between power supply and consumption loads of the system in an off-network state due to the above reason and the like, the charging and discharging states of an energy storage unit generally equipped on an island and the workbench time and the workbench number of the seawater desalination system are adjusted and controlled by taking the generation and consumption relationship (GCR) of a real-time acquisition system, remaining amount of freshwater (RAF) of a seawater desalination system (SDS) and the state of charge (SOC) of a storage unit (SU) as control inputs of the decision system; therefore, the micro-grid system can absorb excess generating capacity of the distributed power supply (DG) and fill missing loads; and simultaneously, the lowest electricity and water demands of users on the island can be ensured when diesel consumption is reduced to the most extent by deciding the switching time and duration of a diesel generator system (DGS).

The invention provides a photovoltaic system based plug and play power management system of user side distributed power sources, which comprises a photovoltaic array, an energy storage unit, and a plug and play inverter which is respectively matched with the photovoltaic array and the energy storage unit, and an instant communication function of the inverter and a remote electric power dispatching center is realized through the communication interface of the inverter so as to reach the plug and play effect and the energy control function of a local power management system, and the energy storage unit plays an aided role. According to the photovoltaic system based plug and play power management system of the user side distributed power sources, provided by the invention, the voltage peak changes in grid-tied and off-grid processes are processed with a rapid sampling and algorithm of software by means of tracking instant impulse voltage and current changes instantly generated by the distributed power sources in the grid-tied and off-grid processes, and the inverter is controlled to run in a way of current source, so that active / reactive power control of the distributed power sources can be realized, finally, the influences can be relieved or eliminated, and the purpose of the plug and play effect and the energy control of the system is realized.

The invention discloses a display drive circuit which comprises a grid line drive circuit, a shielding signal generation circuit and a grid line shielding circuit, wherein the grid line drive circuit is used for separating grid line drive signals of adjacent rows according to a first output enable signal; the shielding signal generation circuit triggers to generate a shielding signal when the grid line drive signals need to be turned off; a first input end of the grid line shielding circuit inputs a first output enable signal, a second input end of the grid line shielding circuit inputs the shielding signal, and an output end of the grid line shielding circuit is connected with the grid line drive circuit; and the grid line shielding signal is used for shielding the first output enable signal according to the shielding signal so as to turn off the grid line drive signal. According to the display drive circuit and the drive method thereof as well as the display device disclosed by the invention, the first output enable signal is shielded directly according to the shielding signal so as to turn off the grid line drive signal and shield the data on corresponding grid line; and display anomaly can be avoided by use of the first output enable signal, and the circuit cost and the circuit space also can be saved.

The embodiment of the invention provides an off-network prediction method and device, relates to the technical field of communication, and solves the technical problem that an existing off-network prediction method is relatively low in accuracy. The method comprises the following steps that: an off-network prediction device firstly acquires service information of a terminal at a first moment, andthen predicts off-network information of the terminal according to the service information of the terminal and a pre-constructed decision tree; wherein the service information comprises: service information, wherein the first duration is between the opening moment of the service and the first moment; wherein the second duration is between the termination moment of the service and the first moment,whether the service comprises at least one of an internet protocol television (IPTV) service, the fault frequency of the service in a first preset time period, the total flow of the service in a second preset time period, a third duration in which the transmission flow of the service meets a preset flow threshold, the bandwidth of the service, the regional type of the service or the flow type ofthe service; wherein the off-network information is used for indicating whether the terminal is off-network at the termination moment of the service.

The invention discloses an off-grid micro-grid electric vehicle ordered charging and discharging load modeling method based on optimized operation and a solving method of the off-grid micro-grid electric vehicle ordered charging and discharging load modeling method. An optimized day-ahead scheduling plan is provided for the off-grid microgrid; First of all, an objective function is established, Determining constraints, Correction data, GUROBI optimization software is called in MATLAB through a toolbox Yalmip to solve the MATLAB; the method has the advantages that electric vehicle load modelingis simplified from a complex nonlinear mixed integer programming problem to a linear mixed integer programming problem, the minimum operation cost of the microgrid is taken as the target, and meanwhile the influence of new energy output on the electric vehicle load is considered. The model is solved by calling the GUROBI, so that engineering personnel can learn and use the model conveniently, theuniversality is good, and the model can be widely applied.

The invention discloses an off-network prediction method, which is used for acquiring user data of a mobile account, and the user data comprises personal information characteristics, consumption behavior characteristics, call behavior characteristics, complaint times and / or network speed. The user data is input into a pre-trained off-network prediction model to obtain an off-network prediction result of the mobile account; and whether the mobile account is off-network at the to-be-tested time point is determined according to the off-network prediction result. The invention further discloses anoff-network prediction device, a server and a storage medium. According to the off-network prediction method provided by the invention, the off-network prediction model is used, and the user data isinput into the model to obtain the off-network prediction result, so that whether the mobile account is off-network or not is accurately predicted, and the off-network prediction accuracy is improved.

The invention discloses an off-grid complementary green smart illumination system, which utilizes sunlight instead of relying on mains supply. During daytime, illumination primarily depends on a sunlight collection and optic fiber introduction illumination sub-system, and when there is insufficient sunlight or it is a rainy day or at night, illumination is supplemented by a photovoltaic off-grid illumination sub-system. The process of supplementary lighting is fully and automatically realized by an automatic light measuring adjustment sub-system so as to achieve a constant indoor illumination. At the same time, an integrated control sub-system monitors the performance parameters of each sub-system at appropriate time in order to provide basis for decision makers to make in-time and accurate decisions. The illumination system herein mainly includes a sunlight collection and optical fiber illumination sub-system 1, a photovoltaic off-grid illumination sub-system 2, an automatic light measuring adjustment sub-system 3, and an integrated control sub-system 4. When there is sufficient sun light intensity outdoor, illumination is provided independently by the sub-system 1, and meanwhile the sub-system 2 implements the function of energy storage. And when there is insufficient sunlight intensity, supplementary lighting is delivered by the sub-system 2. The collection sunlight photovoltaic state parameter of the sub-system 1, the energy storage state parameter of the sub-system 2 and the light measuring and adjustment light state parameters of the sub-system 3 is real-time on-line monitored by the sub-system 4, thus providing a reliable basis for the decision makers.

The invention discloses an automatic grid connection system for a wind turbine asynchronous generator, which belongs to the field of automatic control. When generating power, most large-size wind turbine generators are connected to a grid by converting (inversing) cyclic waves and voltage thereof into the cyclic waves and voltage of the grid, which not only increases the complexity coefficient of equipment and reduces the operating reliability of the equipment, but also increases equipment cost. However, an asynchronous generator can be connected to the grid conveniently, and that is accomplished automatically in the invention. The key point of the system lies in a controller part. The system controls the wind turbine generator to be connected to and separated from the grid automatically, clears the fault of the generator automatically and allows the wind turbine generator to separate from the grid and stop automatically in case of dangerous wind speed.

The invention provides an optical storage off-grid system control method and device, a controller and a storage medium, and belongs to the technical field of off-grid micro-grid control. The method comprises the steps that: a controller determines whether an optical storage off-grid system enters a low-capacity operation stage or not according to the charge state of an energy storage battery; if the optical storage off-grid system enters the low-capacity operation stage, the controller determines whether a DC-to-DC converter and a photovoltaic cell panel in the optical storage off-grid system need to be shut down or not according to the power of an electric meter at an energy storage contactor; and if the DC-to-DC converter and the photovoltaic cell panel in the optical storage off-grid system need to be shut down, the controller controls the DC-to-DC converter and the photovoltaic cell panel to be shut down. According to the optical storage off-network system control method and device, the controller and the storage medium provided by the technical schemes of the invention, the optical storage off-grid system can still realize automatic operation under the condition that the energy storage battery is in low-capacity standby power, the risk of emptying the energy storage battery is reduced, the risk of downtime of the optical storage off-grid system is avoided, and the operation reliability of the optical storage off-grid system is improved.

The invention relates to an energy coordination control method of an off-grid direct-current microgrid. The direct-current microgrid is provided with a photovoltaic power generation unit, a wind powergeneration unit, an energy storage unit and a load unit. The direct-current microgrid is divided into a plurality of working modes according to the grade of the direct-current bus voltage, in each working mode, one or more units of the photovoltaic power generation unit, the wind power generation unit, the energy storage unit and the load unit are used for adjusting the voltage of a direct-current bus and keeping the power balance, when the direct-current microgrid is switched between the working modes, the photovoltaic power generation unit, the wind power generation unit, the energy storageunit and the load unit are switched to the corresponding working modes, and plug and play of the direct-current microgrid under the off-grid condition is achieved. Compared with the prior art, the method has the advantages that the method can still work normally without communication to achieve plug and play, the dynamic characteristics of the direct-current microgrid are improved, the system robustness is improved, and the stability of the direct-current voltage is maintained.