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2572results about "Flexible AC transmission" patented technology

Dynamic power coordination control method for battery energy storage system

The invention discloses a dynamic power coordination control method for a battery energy storage system. The battery energy storage system comprises a plurality of power converters which supply power to a load and are connected in parallel for operation, and is characterized in that: the power converters connected in parallel for operation are divided into two types, and a master-slave control scheme is adopted, wherein one type comprises only one power converter which adopts a constant voltage constant frequency control mode and is called a master node, and the power converters of the other type adopt a constant power mode with a slight droop characteristic, and serve as slave nodes; generally, a power converter with a high capacity is selected to be the only one master node which is specified by an upper-layer monitoring system, and all the other power converters are the slave nodes; and under a stable state condition, active power and reactive power output by the power converters which serve as the slave nodes are set by a power instruction transmitted by the monitoring system, and the output power of the power converter which serves as the master node is dynamically regulated according to a load condition. The method adopting the master-slave control scheme has the advantages that: on the premise of sufficient power capacity, both the voltage stability and frequency stability of a micro-grid system are easily achieved, anti-load disturbance capability is high, and failure recovery time is short.
Owner:中国南方电网有限责任公司调峰调频发电公司 +2

Battery energy storage system based power conversion system and control method thereof

The invention relates to a battery energy storage system based power conversion system and a control method thereof. The power conversion system comprises a battery energy storage system, a bidirectional DC/DC (direct-current) converter, a grid-side current transformer, a filter circuit and an isolated voltage transformer. The battery energy storage system is in parallel connection with a direct-current bus of the grid-side current transformer through the bidirectional DC/DC converter; the grid-side current transformer, the filter circuit and the isolated voltage transformer are connected in sequence; and the isolated voltage transformer accesses to a power grid. The control method includes sequentially monitoring the battery energy storage system, the bidirectional DC/DC converter, the grid-side current transformer, the filter circuit and the isolated voltage transformer by a control circuit. Since the battery energy storage system utilizes battery cells connected in series and is in parallel connection with the common direct-current bus through the bidirectional DC/DC converter, circulation among battery packs is avoided, and capacity expansion of the system is facilitated. Further, by the aid of the monitoring control strategy for SOC (super capacitor state of charge) of the battery energy storage system and battery end voltage, excessive charge or discharge state of the battery energy storage system is avoided, service lives of the battery packs are prolonged, and comprehensive service cost is lowered.
Owner:CHINA ELECTRIC POWER RES INST +2

Battery energy storage system peak clipping and valley filling real-time control method based on load prediction

The invention relates to a battery energy storage system peak clipping and valley filling real-time control method based on load prediction and belongs to the field of power system automatic control. The control method provided by the invention comprises the following steps of: firstly searching similar history daily load data, carrying out expanding short-term load prediction by adopting a linear regression analysis method, building a battery energy storage system peak clipping and valley filling real-time optimization model, solving the battery energy storage system peak clipping and valley filling real-time optimization model by adopting a dynamic programming algorithm, and obtaining the output power of a battery energy storage system at each moment. The control method provided by the invention comprises battery charging and discharging frequency constraint and discharge depth constraint in the real-time optimization model, is used for researching relation between battery life and the charging and discharging frequency and the relation between the battery life and the discharge depth and is beneficial to prolonging the battery life. Minimum load variance is taken as a target function, the peak-to-valley of a load curve can be reduced, the load curve is smoother while constraint conditions are met, and the peak clipping and valley filling application requirement can be met. Local part of the load curve can be smoother by adopting load smoothness constraint.
Owner:北京宝光智中能源科技有限公司

Microgrid energy management system capable of realizing load management

The invention discloses a microgrid energy management system capable of realizing load management. The energy management system comprises a man-machine interaction module, a prediction module, a system analysis module, a dispatching and control module, and a system management module. The system performs collection and monitoring on information of the output power of a distributed power generation unit (including a wind turbine generator, a photovoltaic array and a diesel engine set), the charging-discharging states of a storage battery, the load power, the electric energy quality information of unit nodes, and the like, then carries out data analysis and processing under the condition of satisfying electrical characteristic constraint conditions of operating conditions and physical equipment, formulates a corresponding optimal control strategy according to the current microgrid operating condition and external application requests, coordinates and manages the operations of the distributed power supply, the load and other modules in the microgrid system, optimizes the energy flow and utilization of the microgrid system, outputs by using renewable resources, supplies electric energy capable of satisfying the required quality to user load at the lowest operating cost, and realizes the system optimization and dispatching.
Owner:SOUTH CHINA UNIV OF TECH

Virtual-impedance-based inverter parallel running method

The invention provides a virtual-impedance-based inverter parallel running method, which is characterized by comprising the following steps of: for each inverter, introducing a virtual generator which is connected to a point with the inverter by virtual impedance; performing droop control on the virtual generators, regulating the frequency and voltage amplitude of each virtual generator by utilizing the active power and reactive power of the corresponding inverters respectively, and further calculating voltage directive values of the virtual generators; and based on the voltage directive values, further calculating output voltage directive values of the inverters, and controlling the inverters to output voltages to track the directive values, thereby realizing control over the voltages of the virtual generators and finally realizing the decoupling regulation of the active power and the reactive power. In the method, a control policy for the wireless parallel running of the inverters is realized by utilizing the virtual impedance; and compared with the conventional control methods, the invention is not required to remarkably increase hardware investment, and betters the using effects of droop characteristics to make applicable the droop characteristics to resistive environments.
Owner:STATE GRID ELECTRIC POWER RES INST

Method for comprehensively controlling reactive voltage of wind farm with imported prediction method

A method for comprehensively controlling reactive voltage of a wind farm with imported prediction information includes a planning mode, an online mode and an emergency mode. An operation plan of a power grid and power prediction information of the wind farm are imported in the planning mode, safety of the power grid, safety of the wind farm, safety of wind turbines and economical efficiency of the wind farm are comprehensively considered, and a control scheme for scattering and regulating equipment is formulated in advance; the safety of the power grid, the safety of the wind farm, the safety of the wind turbines and the economical efficiency of the wind farm are comprehensively considered on the basis of control of scattering and regulating of the equipment in the online mode, and the regulating quantity for continuously regulating the equipment is computed; and disturbance duration is extremely short during actual operation in the emergency mode, various reactive compensation devices cannot be easily communicated with a comprehensive reactive voltage control system of the wind farm and cannot be controlled by the comprehensive reactive voltage control system of the wind farm, and accordingly, the various reactive compensation devices are reactively locally controlled in the emergency mode in the design. The method has the advantages of robustness in control and high reliability.
Owner:TSINGHUA UNIV

Control method of battery energy storage system for peak clipping and valley filling in distribution network

ActiveCN103311942ASafe and stable operationMeet the requirements of peak shaving and valley fillingFlexible AC transmissionAc network load balancingSystem safetyAutomotive engineering
The invention discloses a control method of a battery energy storage system for peak clipping and valley filling in a distribution network. The control method comprises the following steps: obtaining a daily load curve on a predicted day according to a load predicating method, and computing the peak value and valley value of the daily load curve; setting a synthesis output valley value after participation of the energy storage system, and setting an initial value of synthesis output peak value; comparing predicated daily load data with the synthesis output valley value and the initial value of synthesis output peak value which have been set, and judging as follows: if the load data is smaller than the synthesis output valley value, charging the energy storage system to complete valley filling; and if the load data is larger than the initial value of synthesis output peak value, discharging the energy storage system to complete peak clipping, so that the synthesis output after energy storage adjustment reaches to the initial value of synthesis output peak value. At the peak and valley moments according to the load curve, the energy storage system is set to be charged once and discharged twice within one day, the requirement of peak clipping and valley filling can be achieved, and charging and discharging balance every day can be kept, so that the service life of the battery is prolonged to the maximum. Moreover, the control method also can ensure safe and stable operation of the energy storage system.
Owner:STATE GRID CORP OF CHINA +2

Direct current de-icing device based on full-bridge modular multilevel converter

ActiveCN102739080ASolve the problem that cannot be adjusted in a large rangeReduce volumeOverhead installationFlexible AC transmissionFull bridgeHigh-voltage direct current
The invention discloses a direct current de-icing device based on a full-bridge modular multilevel converter. The full-bridge modular multilevel converter has a three-phase bridge structure, each phase of the converter comprises an upper bridge arm and a lower bridge arm, the upper and lower bridge arms which are respectively formed by serially connecting N full-bridge power modules end to end, and the full-bridge power modules form a chain type multilevel structure, the front ends of the first power modules of the upper bridge arms of all phases are connected to form the positive pole of a public direct current bus; the tail ends of the Nth power modules of all lower bridge arms of all phases are connected to form the negative pole of the public direct current bus; the tail ends of the Nth power modules of all upper bridge arms are connected with the front ends of the first power modules of the respective lower bridge arms of the phases by smoothing reactors; and the center of the electric reactor serves as the alternating current bus of the phase. The device has high high-voltage direct current output capacity and the direct current voltage of the device can be regulated continuously from zero; on the other hand, the fully compatible chain type scalable vector graphics (SVG) topology can realize quick dynamic reactive regulation; and the device has the combined functions of direct current de-icing and alternating current dynamic reactive compensation.
Owner:BEIJING SIFANG JIBAO AUTOMATION +1
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