3933 results about "Grid connection" patented technology

There is provided a power control method for secondary batteries constituting, in a grid connection system supplying electric power to a power system by combining a power generator where output power fluctuates with a power storage compensator, the power storage compensator and compensating fluctuation of output power of the power generator. The method includes the steps of: dividing the secondary batteries into a “constant power control” group and a “demand responsive” group, and distributing predetermined constant input-output power out of power to be input and output provided to all the secondary batteries in order to compensate fluctuation of output power of the power generator to the “constant power control group” and the remaining input-output power to the “demand responsive” group to control input-output power of the secondary batteries respectively depending on the belonging groups.

A ball grid pad for connecting a ball grid array package to a printed circuit board includes a circular pad area adhered on a ball grid connection surface. A solder mask on the ball grid connection surface has an opening surrounding and spaced apart from the circular pad area. The ball pad includes an anchor trace on the ball grid connection surface wherein the ball pad conductor material extends radially from the edge of the circular pad area to a terminating point beyond the opening of the solder mask so that a portion of the anchor trace is covered by the solder mask. The ball grid connection surface may be an integrated circuit package substrate or a printed circuit board surface.

The invention discloses an energy-saving type cascade multilevel photovoltaic grid-connected generating control system comprising an energy-saving cascade multilevel photovoltaic generating inverter, a controller and a power grid, wherein the multilevel inverter consists of 3n energy-saving type photovoltaic generating modules, wherein n modules are connected in series into one phase of a three-phase inverter; and the single-stage power of each module is converted to realize the buck-boost, the inverting and energy saving and adapt to the wide-range change of the battery voltage with high reliability. 3n photovoltaic cells and energy-saving cells are distributed on 3n modules; the generation of each module is independently controlled, thereby realizing the distributed maximum power track, collecting solar energy to the maximum extent, realizing high efficiency and avoiding the problems of power loss and hot spot caused by the local shade generated when the photovoltaic cells are connected in series; and the invention can flexibly control the stable power of a feeder grid of the multilevel inverter and achieve the functions of reactive power consumption, the power pitch peak control and the like, has the advantage of multilevel inversion and low output harmonic voltage and is suitable for high-voltage, high-power and transformer-free grid connection.

An inverter includes a battery pack connection for supplying energy to or receiving energy from a photovoltaic string, a battery pack, an AC grid connection for supplying power to or receiving power from an AC grid, a connection for supplying power to a home back-up load, an electric vehicle connection for supplying to and receiving power from an electric vehicle (EV) battery, and a control input configured to receive one or more control signals for controlling the flow of power within the inverter. The inverter, under the control of the one or more control signals, converts power received from one of different power sources and provides the converted power to charge a battery of the EV.

The invention discloses an alternating current and direct current hybrid micro-grid system and a control strategy of the micro-grid system. The micro-grid system comprises multiple generation units, load, a distribution line for connecting the generation units and the loads, and a monitoring protection unit; each generation unit comprises a large power grid, grid-connected AC/DC (alternating current/direct current) of the large power grid, an energy storage system, a DC/DC (direct current/direct current) converter of the energy storage system, a wind power generation system, an AC/DC converter of the wind power generation system, a photovoltaic power generation system, a DC/DC converter of the photovoltaic power generation system, and a diesel generator; said load includes AC non-significant load, AC significant load, AC/DC load, DC significant load and DC non-significant load; the distribution line comprises a DC distribution line and an AC distribution line; the operating status of each energy conversion device can be monitored in real time by the monitoring protection unit, two operating ways such as grid connection and isolation of the system can be realized by different control strategies, the distributive generation unit and the energy storage unit realize coordination and cooperation by controlling energy storage DC/DC, photovoltaic DC/DC, and wind power AC/DC, so that the power supply reliability is improved and the significant load can continuously operate.

The invention provides a control method of a grid friendly type distributed power source based on hybrid energy storage. The method comprises the steps of optimally designing a topology structure of the distributed power source, controlling a direct current power supply system in a coordinating mode through a direct current (DC)/DC converter controlling a model normalization model, and self-adaptively controlling a grid of an alternating current (AC) side DC /AC converter. The distributed power source not only can be connected in a large grid to operate so as to reduce the influence of intermittent renewable energy power generation grid connection on the grid and provide support of voltage and frequency for the grid, but also can be connected into a micro-grid to operate as a network unit of the off-network type micro-grid to maintain stability of voltage and frequency of the off-network type micro-grid. When an outer grid breaks down, the distributed power source can realize switch between a grid mode and an island mode so as to improve power supply reliability of important loads in the system. The distributed power source improves technical performance and economic performance of the whole system through matching utilization of an energy type system and a power type energy storage system.

A modular adaptive power management center integrating control and management of multiple electrical power sources such as locally generated solar or wind power, connections to an electrical utility service provider, battery power, and others. The system increases system efficiency by monitoring load requirements and matching available power sources in real time. A wall mounted rack system houses a system backplane and a main system microprocessor. The backplane accepts plug-in power modules including power converters each dedicated to managing one of various energy sources such as local wind or solar sources, as well as utility grid connections and battery backup systems. The system also includes a backup battery bank and a battery power module to control charge/discharge activity of the batteries. A variety of user interfaces are provided including via a local LCD display, LED indicators, and remote access and monitoring through an Internet connection and browser window. The modular nature of the design allows a homeowner/user to “plug-in” additional modules as new power sources become available.

The invention discloses a distributed power source contained power system multi-target reactive-power optimization method in the field of power system reactive-power optimization. The technical scheme includes: 1, deducing a model of a wind-driven generator in power flow calculation; 2, initializing power grid parameters and grid-connected parameters of a distributed power source; 3, constructing an individual vector formed by system reactive-power optimization control variables, and initializing species; 4, performing the power flow calculation according to the initialized species and grid parameters after grid-connection of the distributed power source, and calculating objective function values; 5, performing multi-target optimization by utilizing the harmony search hybrid algorithm based on artificial bee colony; and 6, finishing the optimization process and outputting optimized results. The distributed power source contained power system multi-target reactive-power optimization method is a hybrid optimization algorithm ABS-HS which integrates the advantages of global search of the artificial bee colony (ABC) algorithm with local search of the existing harmony search (HS) algorithm, so that efficiency and robustness of the algorithm are improved.

The invention relates to a liquefied compressed air energy storage system with cold-storage liquid media. The liquefied compressed air energy storage system comprises compressor systems, a cold storage system, a heat storage system, a liquefying system and a turbine power generation system. During energy storage, the multistage compressor system is driven by renewable energy sources, so that compressed air is supercharged to exchange heat with a room-temperature cold-storage liquid medium, the cold quantity stored in the liquid medium is lowered to liquefying temperature, and the compressed air is liquefied through throttling; during energy releasing, the liquid air is supercharged to exchange heat with a high-temperature cold-storage liquid medium, the medium recycles cold energy to give to the liquefying process, and the air is warmed to be vaporized; room-temperature high-pressure air is input into a multi-stage turbine expander for acting, and a power generator is driven to output electric energy; the heat storage system reduces the power consumption of the next stage of compressor, and the stored heat is heated step by step before expansion to raise the intake air temperature; a cold-storage medium with a low freezing point and a high/low boiling point recycles the cold energy of the liquid air, the specific heat capacity of the liquid media is large, and the large-temperature-span heat exchange is realized. The liquefied compressed air energy storage system has the advantages of being simple in structure and stable in performance, can realize integration of energy storage and power generation, and can realize the large-scale grid-connection of renewable energy generation, therefore improving the capacity of a power grid accepting new energy power generation.

The invention provides a direct current micro-grid coordination control method of a light storage electric car charging station, and relates to the micro-grid technology field. The technical problem is solved that a direct current bus voltage is kept smooth and stable. The method employs a storage battery and flywheels for hybrid energy storage, a direct voltage is divided into five levels from high to low, layered coordination optimization control of a direct current bus is carried out, and coordination optimization control of photovoltaic power generation, electric car charging and discharging, load power requirements and grid side converter charging and discharging in a charging station direct current micro-grid is carried out. The method can keep balance of the system power in different operation modes of charging station micro-grid island and grid connection and achieves stable control of a direct current bus voltage.

The invention relates to a low-carbon dispatching method and device for an electric power system based on large-scale wind power grid connection. The low-carbon dispatching method comprises the following steps of: (1) collecting power grid data of a given power grid system in the next dispatching cycle by a dispatching system of the electric power system; (2) capturing active load distribution values of a wind power farm and each generator by a low-carbon dispatching system according to the power grid data collected by the dispatching system of the electric power system; (3) making a new power generation executing plan by the dispatching system of the electric power system according to the active load distribution values of the wind power farm and the generators, which are captured by the low-carbon dispatching system; and (4) sending the new power generation executing plan, which is made by the dispatching center of the electric power system, to the wind power farm and a thermal power plant by a power generation executing system so as to execute the plan. The invention has the following advantages that the economy of power production is considered, and moreover, the protection of ecological environment is paid more attention to at the same time; and requirements for energy-saving and emission reduction are met, and low-carbon power production is promoted.

The present invention has disclosed an optimal control method for reactive voltage of wind power and photovoltaic power centralized grid connection in the field of wind power and photovoltaic power grid connection control technology, comprising: setting actuating stations used to control single wind power plant/photovoltaic power plant, setting substations used to control actuating stations and set master station used to control all the substations; master station calculates setting voltage reference U_ref of each substation; adopting 3σ method to process set voltage reference U_ref to obtain set voltage reference interval; regulating high-side voltage of substation to make it fall in set voltage reference interval; if high-side voltage of substation does not fall in set voltage reference interval, then regulating the equipment in wind power plant/photovoltaic power plant via actuating station. The present invention guides the actual operations of electric power system.

The invention relates to a direct-current micro-grid system and a control method thereof. The direct-current micro-grid system comprises a direct-current power distribution circuit, a bi-directional AC/DC (alternating current/direct current) rectifying/inverting device, a distributed energy generating device, an energy storing device, direct-current loads, alternating-current loads, a urban microclimate interactive system, a clock interactive system, a micro-grid control system and micro-grid protecting devices, an upper scheduling management system is arranged in the micro-grid control system so as to form layered management for micro-grid energy. The direct-current micro-grid control method includes: entering a grid connection mode or an island model according to working state of a large power grid, and determining the working states of the energy storing device and the distributed energy generating device according to information of the urban microclimate interactive system and the clock interactive system. The direct-current micro-grid system can independently supply power to the alternating-current and the direct-current loads and can be connected with a power grid to generate power according to processed result of urban microclimate interactive information, so that requirements on power supply for users are met, cost is reduced, designing, controlling, operation and maintenance of a micro-grid are benefited, and reliability, economy and efficiency of the micro-grid are effectively improved.

Disclosed is a V2G charging station. Peak cutting and valley leveling of a power grid are realized through the V2G charging station; a large-capacity energy storing device is arranged in the charging station, so that peak-valley adjusting of the power grid is enabled not to completely depend on electromobile users; by a mode of searching nearby electromobiles, the electromobiles are enabled to sell or purchase power in a centralized manner, so that cost for grid connection of the electromobiles is lowered, impact on the power grid due to sudden grid connection of all electromobiles is reduced, and power supply stability of the power grid is maintained; buffering time for grid connection for power selling or purchasing of the electromobiles is provided by calculating remaining charging and discharging time through the energy storing device.

The invention relates to a semi-liquid metal electrode energy storage battery, belonging to the field of an energy storage battery, and aiming at solving the problems that the all-liquid metal battery is narrow in battery material selection range and high in running temperature, and has potential safety problem. The semi-liquid metal electrode energy storage battery comprises a shell, a positive pole, electrolyte, a negative pole and a collector, wherein the positive pole is alloy made from one or more of Sn, Sb, Pb, Bi and Te; the negative pole is alloy made from one or more of Li, Na, Mg and Ca; and the electrolyte is a mixture of inorganic salt mixture and ceramic powder. When the semi-liquid metal electrode energy storage battery runs, the positive pole is in a semi-liquid state structure with alloy solid phase distributed in liquid phase, and the electrolyte is melted into semi-liquid state paste, so that the short circuit of the positive pole and the negative pole can be effectively prevented, the energy storage cost is lowered, the working temperature of the battery is reduced, the corrosion speed of the shell is slowed down, the service life of the battery is prolonged, the safety and the reliability of running can be improved, and the semi-liquid metal electrode energy storage battery is suitable for storing energy for new energy power generation grid-connection, frequency modulation and peak-load regulation of an electrical power system as well as smart power grid construction.

The invention relates to a presynchronization control method based on a virtual synchronous generator. The method comprises the steps that a three-phase network voltage amplitude value Vg, a three-phase network voltage frequency omega g and a three-phase network voltage phase angle theta g are obtained; a voltage amplitude value Vo output by an inverter, voltage frequency omega o output by the inverter and a voltage phase angle theta o output by the inverter are obtained; a frequency feedback integration element is cut in; a voltage feedback integration element is cut in; a proportional integral adjuster III is cut in; and a grid connection switch is closed, so that the synchronous generator is connected into a power grid. According to the technical scheme, the fact that before virtual synchronous generator grid connection, the frequency, the amplitude, the phase and the grid voltage output by the virtual synchronous generator are the same can be guaranteed, accordingly small grid connection instant impact current is achieve, and inverter smooth friendly grid connection is guaranteed.

The invention discloses a networking method for a micro grid. The method is characterized in that: an AC generation source is connected with a DC bus through an AC/DC converter; a DC generation source is connected with the DC bus through a DC/DC converter; the DC bus is connected with a large power grid through a grid-connected inverter; the DC bus is connected with a power accumulator; and the AC/DC converter, the DC/DC converter and the grid-connected inverter are controlled by a system controller. The micro grid of the invention can be connected with a plurality of generation sources with different power generation properties and promote the development of micro grids. A networking structure of the DC bus can reduce the control difficulty of the micro grid and improve the power supply quality of the micro grid. The networking structure of the DC bus has a great advantage in connection of the micro grid to the large power grid and can adjust the grid-connection output active power and inactive power of the micro grid through the grid-connected inverter during grid connection in favor of the large power grid.

The invention provides primary frequency modulation control method and system of a new energy power station. The primary frequency modulation control method includes: calculating active power output regulating variables and new active power reference values on primary frequency modulation of the new energy power station; evaluating active power output margins of power generation units in the new energy power station; calculating the active power output regulating variables of the power generation units according to the active power output margins; according to the new active power reference values and the active power output regulating variables of the power generation units, calculating the active power reference values of the power generation units, and the power generation units performing active power output according to the active power output values. Compared with the prior art, the primary frequency modulation control method and system has the advantages that both the active power output regulating variables of the new energy power station and the active power output margins of the power generation units are taken into consideration, and grid-connection frequency of the new energy power station can be regulated under the premise of safe operation of the power generation units.