586 results about "Active power control" patented technology

The invention relates to a control system of a flexible wind power DC convertor on the sea, which pertains to the technical field of power transmission in wind power generation and comprises the doubly closed loop control structure of a sending end rectifier on the sea and the doubly closed loop control structure of a receiving end inverter on the coast; the doubly closed loop control structure of the sending end rectifier on the sea is used for controlling the active power of a flexible DC transmission system and the voltage stability of a wind power AC system; the doubly closed loop control structure of the receiving end inverter on the coast is used for controlling the constant voltage of the DC side of a receiving end convertor and the dynamic regulation of the reactive power of the main network accessing end of the receiving end convertor; two control structures are mutually independent and no data communication exists between the two control structures. The control system can fast and correctly control the active power of wind power transmission on the sea as well as promote the stability of the wind power AC system on the sea and the transmission efficiency and the power quality of the whole DC transmission system.

The invention discloses an active power control method of master station-end wind power field subject to wind power grid integration for a large-scale wind power integrated network, and belongs to the technical field of power systems. The method comprises the following steps of: providing a regional power grid active scheduling framework containing wind power field control, predicting newly increased functional short and ultra-short wind power by adopting the control principle of wind power-based predicted ''generating plan tracking'' serving as a main aspect and wind power unit ''direct frequency modulation participation'' serving as a secondary aspect, and describing auxiliary frequency modulation; providing data flow design of an active scheduling system containing wind power field control; providing a wind power field active power control mode to improve the wind power receiving capacity of the power grid by wind power participating power grid active control based on the current wind power control technology; and providing stable section-based wind power field active power control so as to further solve the wind power consume problem under high wind power permeability rate by using the renewable energy source such as maximum dissipated wind power and the like as principle on the premise of ensuring that the wind power of the system is connected to the important section stability margin.

The invention relates to a single-phase universal electric energy quality controller for power supply for electrified railways, and belongs to the technical field of flexible AC power transmission and distribution; the invention comprises a single-phase multi-coil transformer composed of a primary coil and n secondary coils, so that the secondary coils of the transformer can be connected in parallel with n voltage sources of current transformers; n capacitors are connected with n voltage source current transformers, so as to form a single-phase chain-type H-bridge current transformer with n chains; the AC terminal of the H-bridge current transformer is directly connected with the traction grid through a reactor. The invention has the functions of active power control, reactive power compensation and harmonic compensation, so as to resolve three-phase voltage unbalance, voltage fluctuation, low power factor and harmonic pollution and so on that exist in ER traction transformer stations, effectively lower the capacity of traction transformers, increase ER transport capacity and transportation capability. Moreover, the invention is characterized in small occupied area, little loss and low cost, in order to gain perfect harmonic suppression characteristics and dynamic response features, and provide convenience in industrial production and improve device reliability.

The invention discloses a method for cooperatively controlling a multiport flexible DC power transmission system. The DC power transmission system comprises a dominant convertor station, a wind power plant convertor station, an auxiliary convertor station and an active power control convertor station. The dominant convertor station is used for controlling the DC voltages of the entire system. The wind power plant convertor station is in charge of collecting the active power of a wind power plant group. The auxiliary convertor station is used for assisting to achieve control over the DC voltages of the system. The active power control convertor station is used for transforming constant active power to an AC side power grid. The auxiliary convertor station and the active power control convertor station are both controlled based on the improved DC voltage -active power coastdown adjusting characteristics. The method for cooperatively controlling the multiport flexible DC power transmission system has the advantages of being used for DC voltage control and active power distribution of all convertor stations of the multiport flexible DC power transmission system under any operation stations, and it is guaranteed that the multiport flexible DC power transmission system is in smooth transition between various operation states.

The invention is directed to a system for electromagnetic communications that includes a semiconductor die; at least one amplifier on the die to amplify an input signal and generate an output signal; and an active bias control component on the die for adjusting biasing of the amplifier so that the amplifier is operable in a plurality of frequency bands. In one embodiment, a PCS band and W-CDMA power amplifier may be integrated on the same power amplifier die, and different output power requirements may be addressed by the use of an Si DC-DC converter. Such a converter may provide efficiency enhancements to the overall system through the use of dynamic bias control under active power control situations from the network. In addition, the converter may be used in a voltage up-converter state that allows a W-CDMA optimized power amplifier to operate at PCS frequencies and output power levels.

A method of controlling inertia response of variable-speed wind turbine generator includes following steps. A maximum wind power of the wind turbine is gotten through a wind speed ν_w and a rotation speed ω_r at the hub of the wind turbine based on a maximum wind power tracking control strategy. The maximum wind power is set as an active power control reference value P₀ of the wind turbine. A grid frequency f is obtained via a frequency measurement equipment. An additional active power control reference value ΔP of the wind turbine is generated based on the grid frequency f via an additional control block, and the additional active power control reference value ΔP is added on the active power control reference value P₀, wherein a total of active power control reference value of the wind turbine is P₀+ΔP.

The invention discloses a wind power plant active power control method based on model prediction control. Wind turbine generators are classified according to the wind speeds of the wind turbine generators, a local linearization state-space model of each type of generators is established by adopting an equivalent modeling method, dynamic response characteristics of different types of generators are taken into account based on a designed model prediction controller, power grid dispatching values are distributed to each type of generators according to certain priority, then active reference values obtained by each type of generators are revised by the model prediction controller, and revision values are distributed to all the generators in proportion. For the goal of wind power plant active power control, the operational difference among the generators is taken into account, and the power grid dispatching value can be quickly tracked based on the model prediction control.

The invention discloses a variable-speed wind turbine generator inertia response simulating control method. The method comprises the steps that according to the wind turbine generator hub wind speed vw and the wind turbine generator rotating speed omega r, the active-power control reference value P0 of a wind turbine generator is set based on a maximum wind energy power tracking control strategy; extra controls are added through power grid frequency values on the basis of maximum wind energy power tracking control, according to operation conditions of the wind turbine generator, short-time constant-power supporting is carried out through table searching or online adjusting to achieve inertia response simulation, and meanwhile the wind turbine generator active power recovery process is achieved according to a certain power curve. The variable-speed wind turbine generator inertia response simulating control method can overcome the problems that the rotational inertia of a wind turbine generator is not sufficiently utilized, the wind turbine generator is out of a reasonable operation range, inertia control is lack of flexibility, response time is long, particularly, the rotating speed of the wind turbine generator is too low, and the torque and the rotator current of the wind turbine generator are too large in the prior art. The variable-speed wind turbine generator inertia response simulating control method can effectively reduce the frequency deviation amplitude and the rate of change after large frequency disturbance accidents, and improves frequency stability of an electric power system.

The invention discloses an inverter grid-connected control method based on the virtual synchronous generator technology and belongs to the field of distributed power generation system grid-connected researches. According to the technical scheme, the method includes the steps that a grid-connected inverter phase voltage phase value is obtained through calculation by simulating a conventional synchronous generator unit active power control method; a grid-connected inverter phase voltage amplitude value is obtained through calculation by simulating a conventional synchronous generator unit reactive power control method; a three-phase voltage reference value is worked out according to the inverter phase voltage phase value and the inverter phase voltage amplitude value, a three-phase modulated wave is figured out according to direct current side voltage obtained through detection, and the three-phase modulated wave is compared with a carrier wave to obtain six switching signals to control turn-off and turn-on of switching devices in a main circuit. System damping and active power-frequency droop control are achieved by means of control link signals, and power grid frequency does not need to be detected. The method simplifies a control structure and avoids the problems caused by a frequency detection link. Effectiveness of the method is verified through simulation and experiment results.

The invention relates to a symmetrical drop-off low voltage ride through reactive power control method of a photovoltaic power generation system. A controller detects whether a grid connection point voltage drops off in real time, and if the voltage does not drop off to 90% of a nominal voltage, an active current reference value id* is taken from an outer voltage loop, and grid connection control when the voltage is normal is adopted; if the grid connection point voltage drops off below 90% of the nominal voltage, the outer voltage ring is disconnected, low-voltage ride through control is adopted, namely inner current loop control is adopted, definite reactive power is output to a power grid by the photovoltaic power generation system according to the drop-off amplitude, and recovery of the voltage of the power grid is facilitated; if it is detected that the voltage recovers, the active power of the photovoltaic power generation system recovers at 10% rated power/second, reactive power is gradually reduced to zero at the same time, and finally the grid connection control when the voltage is normal is adopted. According to the method, an outlet current of a photovoltaic grid-connected inverter is limited within an over-current protection action current, reactive power support is provided for the grid voltage to recover to the normal value, investment of reactive power equipment is saved, and resources are saved.

The invention discloses an active power control method for wind power plant participated power grid frequency modulation. Wind turbine units are divided into a critical unit, a low air speed unit and a high air speed unit according to the operating conditions of the wind turbine units; the active dispatching power is modified according to the real-time frequency deviation and the active power adjustable value of the wind power plant to obtain active power modification values of the wind power plant participated power grid frequency modulation; and then the active power modification values are allocated to each wind turbine unit of each type according to the types of the wind turbine units to enable the wind turbine units of each type to participate in the frequency modulation based on a certain sequence. According to the active power control method, the wind power plant is taken as the object and the wind power plant participates in the power grid frequency modulation within a certain frequency deviation; the active power control method considers the reasonable distribution of the frequency modulation amount among the units according to the different operating conditions of the units and the active adjustable amount of the wind turbine units; and therefore, the wind power plant can make response rapidly, and the power grid frequency deviation can be reduced to the greatest extent.

The invention discloses a wind power station active power control method which includes the following steps. Firstly, a wind power station and a net value of active power of a network point are measured. Secondly, whether a difference between objective power and actual power is in a dead zone threshold value range of power deviation is judged. Thirdly, the maximum active power of all wind turbine generator units is calculated. Fourthly, an active margin addition queue and an active margin reduction queue are generated. Fifthly, an active margin addition sum and an active margin reduction sum of all the adjustable wind turbine generator units in operation are calculated. Sixthly, a starting queue and a halting queue are generated. Seventhly, a power regulating strategy is confirmed. Eighthly, a control order is emitted to the wind turbine generator units. Ninthly, returning to the first step is not performed until the wind turbine generator units perform the order. According to the wind power station active power control method, a called active power regulating order can be automatically distributed to a single wind turbine generator unit for actuation. Labor intensity of operation staff in the wind power station and loss of generated energy by the wind power station are greatly reduced. A responding speed of a called power object, economic benefits of the wind power station and precision in regulating power are improved.

The invention discloses a method for controlling the frequency modulation of a micro-grid battery energy storage system based on fuzzy control, and belongs to the technical field of electric power system micro-grids. On the basis of the conventional proportion integration differentiation (PID) control, fuzzy control and an implementation mode thereof are introduced into the method, and the method comprises important components such as fuzzification, fuzzy rules, fuzzy reasoning, defuzzification, PID control and the like. According to the method, the micro-grid frequency deviation and the micro-grid frequency change rate are fuzzified into input of a fuzzy controller, PID control parameters of active power output control are output according to a fuzzy control rule, and an active power output reference value Pref of the battery energy storage system is finally output to control the active power output of the micro-grid battery energy storage system. Compared with the conventional PID control, the method has very strong adaptability to the switching of micro-grid parallel network/isolated network operational modes and to the nonlinearity and the time variability of electric network operational parameters, has a good dynamic response characteristic, and effectively improves the active power control accuracy of the battery energy storage system and the frequency stability of the micro-grid.

The invention relates to a power coordinated control method for a multi-terminal flexible DC transmission system. According to the method, a converter station with larger rated capacity is selected from a VSC-MTDC (Voltage Source Converter Multi-Terminal DC) system to serve as a main converter station, constant DC voltage control is performed on the main converter station, the other converter stations are divided into two groups, adaptive droop control and constant active power control are respectively performed on the two groups of converter stations, the main converter station performs regulation independently when the unbalanced power in the system is within a regulating range of the main converter station, and when the main converter station is fully loaded or out of operation, the redundant unbalanced power is regulated by a converter station adopting the droop control, the active power outputted by the converter station is automatically regulated according to DC side voltage changes caused by the unbalanced power so as to enable the system power to achieve a balance again. The power coordinated control method can avoid a phenomenon of out-of-limit voltage, reduce voltage fluctuations at the DC side and make full use of the active power capacity of the converter station. The method can effectively improve the control quality of the multi-terminal flexible DC transmission system, and meet control requirements of the system under different operating conditions.

The invention provides an active power control method in a wind power plant. The active power control method in the wind power plant comprises the steps of computing the active power prediction errors of all predicted points in the wind power plant, establishing a wind power plant active power prediction error distribution function, establishing a wind power plant active power prediction error distribution module, a wind power plant active power prediction confidence degree module and a wind power plant active power control module in sequence, optimizing the wind power plant active power control module, obtaining an optimization confidence weight of all unit sets, and controlling the active power of the wind power plant. The active power control method in the wind power plant is based on historical data analysis. By means of the active power control method in the wind power plant, the power-outputting error of the wind power plant is reduced, the reliability and accuracy of the wind power plant are guaranteed, and a powerful guarantee is supplied to the wind power plant in the grid-connected operation.

The invention discloses an active power flow optimizing distribution method for an alternating-direct current parallel system containing soft direct current power transmission, and solves the reasonable distribution problem of the active power flow of the alternating-direct current system under the alternating-direct current parallel operation mode of the soft direct current power transmission. The method comprises the steps of obtaining basic parameters of a power grid to be analyzed; establishing corresponding target functions by taking factors such as alternating-direct current equipment loss, avoiding parallel loop current, the safety and stabilization of the power grid, the utilization rate of the alternating-direct current equipment and fault rate as target conditions according to the obtained basic parameters of the power grid; establishing multiple target optimization functions according to all established target functions; designing a subjection function for each target function according to the fuzzy theory; and resolving the optimal solution of the multiple target functions by adopting a fuzzy algorithm. The method considers the constrain of multiple target conditions, obtains the optimal active power control reference value under the alternating-direct current parallel operation of the soft direct current power transmission system by resolving the multi-target optimal function, and is more reasonable in comparison with the method relying on experience to set the active power reference value.

The invention relates to a micro-grid economic and optimal operation and scheduling method based on an improved quantum genetic algorithm. The micro-grid is in a grid-connected mode operation state and comprises multiple micro sources and loads, wherein the loads comprise electric loads and thermal loads; and the micro sources comprise a micro turbine, a wind turbine, a photovoltaic cell, a fuel cell, a storage battery and an electric vehicle. The method comprises the following steps: S1, state information of each load and each micro source in the micro-grid is acquired; S2, with minimum of operation cost and pollutant treatment cost as a target, a multi-target economic scheduling model is built; S3, the improved quantum genetic algorithm is adopted for carrying out optimal solution on the multi-target economic scheduling model, and the optimal active power of each micro source is acquired; and S4, according to the optimal active power of each micro source, active power output by each micro source is controlled. Compared with the prior art, the micro-grid formed by distributed power sources operates in a more economic, flexible and environment-friendly mode, and power generation advantages of the distributed power sources can be taken.

The invention relates to an electrified railway in-phase power supply device and a multi-target coordinated instantaneous current control method adopted by the device. After the in-phase power supply device is used, the electrified railway whole-line in-phase power supply can be realized, the output power of two power supply arms of a traction transformer can be balanced, and the negative sequence problem can be thoroughly solved; the load reactive power and the harmonic current can be compensated, and the electric energy quality of a traction power supply system can be comprehensively improved; the voltage of a traction electric network can be stabilized, the transient state stability of the voltage can be improved, the power supply distance of the power supply arms can be increased, and the amount of power substations can be reduced; the electrified railway in-phase power supply device and the multi-target coordinated instantaneous current control method are multiple in targets, the multi-target can be simultaneously controlled, the control harmony at two sides can be guaranteed, the dynamic response capability is stronger; a rectification side inverter takes the active power transfer and the stable direct voltage as a control target, and participates the reactive power control; and an inversion side inverter performs active power, reactive power and harmonic wave control, and participates the stable control of the direct voltage.

The invention provides a d-q axis parameter identification method for a grid-connected inverter of a photovoltaic power generation system. The d-q axis parameter identification method includes: an inverter control reference value Udc-ref and Qref jump are arranged on the grid-connected inverter of the photovoltaic power generation system, or a three-phase short circuit fault is manufactured on the side of a power grid so as to collect disturbance data required by parameter identification; d axis parameters of the grid-connected converter are calculated according to the collected data, and the d axis parameters comprise filter inductance, d axis inner ring current control ring proportionality coefficients, inner ring current control ring integral coefficients, outer ring active power control ring proportionality coefficients and outer ring active power control ring integral coefficients; and a filter inductance parameter is fixed to be a d axis identification result, q axis parameters of the grid-connected inverter are calculated according to the collected data, and the q axis parameters comprise q axis inner ring current control ring proportionality coefficients, inner ring current control ring integral coefficients, outer ring reactive power control ring proportionality coefficients and outer ring active power control ring integral coefficients. The d-q axis parameter identification method for the grid-connected inverter of the photovoltaic power generation system reduces order and identification difficulty of a model to be recognized and improves identification accuracy.

The invention provides an active power control method of a wind power station for improving the power generation efficiency of the wind power station. The active power control method comprises the following steps: firstly, calculating the maximum theoretical generating power at the next moment of every wind power unit in the wind power station; coordinating and controlling by using long and short control periods, reasonably arranging the on-off of every wind power unit and controlling a target value to realize the optimized control of the reactive power output of the wind power field. According to the active power control method, in the long control period, the control target value distributed to the a blower is reasonable, and the control precision can be guaranteed; in the short control period, the active power of a part of wind power units can be quickly adjusted to eliminate the predict bias of the maximum theoretical generating power of the wind power unit and the fluctuation of the wind power, so that the active power output of the entire wind power station tightly follows the control target value, the power generating efficiency of the wind power station is improved greatly, and the running economy of the wind power unit is improved; the active power control method is applicable to perform the active power control on the wind power station including a stall type blower or a part of wind power units which can not participate in the active control under certain condition.

The embodiment of the invention discloses a method and system for active power control of wind turbines. The method comprises the steps of classifying the wind turbines according to the capability of the wind turbines participating in wind power plant automatic gain control (AGG) boost/reduction power control, and dividing the wind turbines into boost power wind turbines, reduction power wind turbines and power-nonadjustable wind turbines; setting a boost power priority sequence of the boost power wind turbines according to boost power stability, and setting a boost power priority sequence and distribution strategy; setting a reduction power priority sequence of the reduction power wind turbines according to reduction power stability, and setting a reduction power priority sequence and distribution strategy; and controlling the wind turbines to execute boost power or reduction power operation according to the wind power plant AGG boost/reduction power control requirements. According to the wind turbine active power control scheme, factors affecting the service lives of the wind turbines can be fully considered, grouping is performed according to the characteristics of the factors, and corresponding control sequences and strategies are selected to perform active power regulation on the wind turbines, and thus the aging of the wind turbines is slowed down.

The invention discloses a wind power plant layer active power control system which comprises a power setting device and a power distributing device. The power setting device is used for classifying units according to unit operation information, collected by a wind power plant supervisory control and data acquisition (SCADA) system, of wind generating sets and super-short-term prediction power information obtained form a wind power prediction system, receiving power instructions issued by a superior dispatching system, obtaining setting instructions and a control circle of power to be distributed, judging whether the output needs to be increased or reduced in a wind field, and sending instructions whether the output is conducted or not to the corresponding power distributing device according to a judged handling pattern. The power distributing device is used for issuing control instructions to a fan control system according to current unit classification information and set power distribution strategies, and the fan control system is used for controlling all classes of units. The wind power plant layer active power control system can well control and analyze the active power of a wind power plant so as to ensure the safe and reliable operation of the wind power plant.

The invention discloses a self-balanced quick load-reducing control method for a microgrid. The method comprises the following steps: determining an equivalent inertia constant of the microgrid, calculating a power balance of the microgrid and evaluating the disturbance amplitude in the microgrid; lowering the changing speed of frequency respectively through frequency responsive active power control of an energy storage system and droop control of a wind turbine; and balancing the initial power vacancy in the microgrid by virtue of rotary kinetic energy, a load adjusting effect and a distributive power supply adjusting capacity, calculating power to be reduced according to the power balance, and obtaining the dynamic characteristics of the system frequency when no spinning reserve is available according to the requirement on load reducing time under various power vacancies. According to the method disclosed by the invention, when the microgrid operates independently and relatively great disturbance occurs in the microgrid, self-balanced load reduction is implemented to eliminate power unbalance in the microgrid by calculating the equivalent inertia constant of the microgrid and evaluating the disturbance amplitude in the microgrid on line.

The invention provides a control method for distribution of an active power and a reactive power of a wind power generator, and belongs to the technical field of wind power generation. The control method of distribution of the active power is listed as follows: data of all wind power generators in a wind power plant are acquired in real time, and the real-time total active power, the total reactive power and average wind speed of the wind power plant are calculated; the real-time total active power of the wind power plant and the total active power with a set value issued by the wind power plant are compared and judged so that a power differential value delta P is obtained; a range value of the total active power of an electric field is set based on the power differential value; the total active power of the real-time wind power generators in the current wind power plant is maintained to be within the set range value of the total active power, a power distribution value of each wind power generator is calculated to be the real-time active power value of each wind power generator and maintained to be unchanged within the range. The active power and the reactive power of the wind power generators can be simultaneously controlled. The total power of the wind power generators is maintained to fluctuate in a stable environment so that interference of a power grid is reduced.