228results about How to "Suppresses voltage fluctuations" patented technology

An interface device transmits a reactive power command depending on a power system from a voltage regulation device of the power system to a wind power generation apparatus electrically connected to the power system, and the wind power generation apparatus receives the reactive power command. Then, the wind power generation apparatus outputs reactive power according to a value obtained by adding, to a reactive power command, another reactive power command for suppression of voltage fluctuation caused by output power of the wind power generation apparatus.

A desired value of reactive power flow between a to-be-controlled power system and an adjoining power system is determined according to measured values of the reactive power flow and an effective power flow and desired voltage values of the to-be-controlled power system and of the adjoining power system. Thereafter, a required value of a reactive power of the to-be-controlled power system is calculated according to the desired value of the reactive power flow, the measured values of the reactive power flow and the effective power flow, and the desired voltage value and a measured voltage value in the to-be-controlled power system. Thereafter, a control apparatus having an electric capacity near to the required value of the reactive power is selected from control apparatus arranged in the to-be-controlled power system to make the selected control apparatus adjust a voltage of the to-be-controlled power system. Therefore, cooperation of the to-be-controlled power system with the adjoining power system can be performed by collecting locally-existing-information, and a voltage fluctuation and/or a reactive power fluctuation in the to-be-controlled power system can be immediately suppressed.

The invention belongs to the field of power systems, in particular to a reactive-load compensation equipment application scheme for large-scale wind power delivery system. As for the large-scale wind power delivery system, the invention, aiming to meet the needs of power delivery and wind power access, through reactive power balance analysis in different level years and under different operation modes, provides the capacitive and inductive reactive power demands of each substation in the system, and provides a configuration scheme for low pressure side fixed switching reactive compensation equipment such as capacitors, reactors and the like and dynamic reactive-load compensation equipment such as controllable reactors, static var compensators and the like. The provided configuration scheme can ensure voltage at each point in the system is controlled within a reasonable range under different operation modes, and meanwhile the dynamic reactive-load compensation equipment can meet the requirements of reactive power control of the grid and the voltage under wind power fluctuations with a strong engineering adaptability.

The invention discloses a voltage and power regulator based on the composite energy storage of a storage battery and a super capacitor. The regulator comprises an energy storage module, an electricity-electron transformation module and a transformer; the energy storage module comprises a plurality of composite energy storage units and the electricity-electron transformation module comprises a plurality of electricity-electron transformers; all the composite energy storage units are connected at the direct current bus side of the electricity-electron transformers in parallel and the alternating current side of each electricity-electron transformer is connected with the auxiliary-side winding of a voltage transformer correspondingly while the original-side winding thereof is connected into a power network. When in normal operation, the regulator can provide reactive power compensation for the power network to effectively stabilize the active power fluctuation; when failure or switching load transmission operation occurs in the power supply line, the regulator provides short-time power supply for load so as to avoid load power supply interruption and further rapidly traces the voltage magnitude and phase of spare lines, thereby realizing that no impact is made in a spare power circuit.

The invention discloses a tidal current control device for a V/v traction substation of an electrified railway. The device consists of a static power adjuster, a TCR filter and an LC filter (FC), wherein the static power adjuster is mounted on the secondary side of the V/v traction substation, and a back-to-back structure is formed by the static power adjuster and a capacity on the public direct current side; the alternating current side of a current converter is connected to power supply arms on the secondary side of the traction substation respectively through a voltage drop transformer; an FC filter is connected to a phase a of the secondary side of the V/v traction substation, and the TCR filter is connected to a phase b of the secondary side of the V/v traction substation. All parameters are calculated by capacity optimization, so that the cost and the system harmonic absorption content can be reduced. A double-closed-loop controller is used for controlling the tidal current distribution of the two power supply arms, so that multi-mode tidal current control is realized; by matching of the V/v traction substation, the TCR filter, the FC filter and the static power adjuster, multi-mode tidal current double-closed-loop control on the traction substation of the electrified railway is realized; voltage fluctuation is suppressed, main harmonics are effectively shielded, and comprehensive negative sequence and reactive treatment is realized.

A method for manufacturing a semiconductor device according to the present invention has a step of forming a plurality of MOSFETs each having a channel of a first conductivity type in a stripe on the first major surface of a wafer; a step of implanting an impurity of a first conductivity type into the second major surface of the wafer, and performing a laser annealing treatment in a stripe leaving equidistant gaps, to form a buffer layer that has been activated in a stripe; a step of implanting an impurity of a second conductivity type into the second major surface of the substrate after forming the buffer layer, and performing a laser annealing treatment on the entire surface of the second major surface, to form a collector layer, and to activate the buffer layer; and a step of forming an emitter electrode on the first major surface, and forming a collector electrode on the second major surface.

The invention discloses a positive and negative sequence double-ring superposition control method of distribution static synchronous compensator based on instantaneous power balance, which consists of a positive sequence control ring and a negative sequence control ring. The method comprises following steps: deducing a current-voltage conversion formula in a d-q positive-sequence and negative-sequence coordinate system according to an instantaneous power balance formula to obtain a positive-sequence voltage modulation signal and a negative-sequence voltage modulation signal; superposing the positive-sequence voltage modulation signal and the negative-sequence voltage modulation signal to obtain a DSTATCOM output voltage modulation signal; and modulating by a triangular carrier wave to produce a PWM drive signal to control the action of an intelligent power module IPM to generate a required compensation voltage. The control method can achieve unbalanced three-phase voltage control of a common connection point, and the current-voltage conversion formula in the d-q positive-sequence and negative-sequence coordinate system is deduced by the instantaneous power balance formula, thus obviating complex mathematic operation in conventional current control method and further lowering the cost.

This invention provides a small package board integrated with power supply capable of supplying a low level of voltage and high level of current to an IC while achieving a low height of its power supply. It becomes hard to saturate an inductor magnetically when the surface of a copper wire is coated with a magnetic layer, and the inductor can accordingly be provided with a sufficient degree of inductance. A multiplicity of inductors can be provided within a confined space by arranging a multiplicity of inductors in parallel, and by fixing them with resin so as to form an inductor array, thereby making it possible to divide a power supply. The number of power supply lines is increased by dividing the power supply so as to reduce the level of current in an individual power supply line, so that a high level of current can be supplied to an IC chip. Further, a distance between a power supply and the IC chip can be decreased by incorporating a power supply module into the package board so as to reduce generation of heat and curb a drop in voltage in the power supply line, thereby making it possible to supply a high level of current to the IC chip.

The invention provides a voltage fluctuation restraining method for a high-frequency zero-sequence voltage injection cascaded static synchronous compensator (STACOM) and belongs to reactive compensation device control methods of power electronics. The method comprises the five steps that firstly, a power grid voltage vector angle is obtained, and synchronous rotation transformation among three kinds of signals such as power grid voltage, compensating currents and a modulating signal obtained according to a master control algorithm is achieved; secondly, compensating current detection and coordinate transformation are carried out, and a triple frequency zero-sequence voltage phase angle is obtained through calculation; thirdly, a triple frequency zero-sequence voltage amplitude is obtained through calculation; fourthly, the triple frequency zero-sequence voltage phase angle is obtained, and a final modulating signal is obtained by adding an instantaneous value to the modulating signal obtained according to the master control algorithm; fifthly, triple frequency zero-sequence voltage injection and PWM signal generation are carried out, three-phase PWM signals are generated, and STACOM capacitor voltage fluctuation restraining is completed. The capacitor voltage fluctuation frequency on the direct current side of the STACOM is converted into quadruplicated frequency from double frequency, the fluctuation amplitude is reduced by half, direct current voltage is stabilized, and the service life of a capacitor is prolonged.

In this method, the space voltage vector of the alternate current output voltage of the inverter, according to its valve in the Alpha, Beta coordinate system, is arranged into the vector distribution map of a hexagon, which is combined by 24 equilateral triangle and the corresponding status of the switch, the optimization modulation is processed. The optimization allows only one switch change status when the adjacent switches switch over.

The invention discloses a method and system for allocation of the reactive compensation capacity of a microgrid. According to the method and system for allocation of the reactive compensation capacity of the microgrid, system data of the microgrid are obtained by an acquisition module, a reactive power optimization model is established by a processing module according to the system data and preset constraint conditions, an optimization result is output by an optimization module according to the reactive power optimization model, and then reactive power optimization is carried out on the microgrid. According to the method and system for allocation of the reactive compensation capacity of the microgrid, reactive power optimization is carried out on the microgrid to achieve the purposes of the minimum active power loss of the microgrid and the minimum average voltage deviation of the microgrid through the reactive power optimization model, the reactive compensation capacity of a reactive compensation device when the reactive power optimization value is smallest serves as an optimization result, voltage fluctuation, caused by output fluctuation of a micro source, of the microgrid can be effectively restrained, stability of the microgrid is improved, power quality of a power supply is improved, loss of the microgrid is reduced, and the overall utilization rate of electric energy is improved.

The embodiment of the invention discloses a method and system for inhibiting voltage fluctuation of a photovoltaic power station. The method includes the steps that a first voltage Vp1 and a first current Ip1 of a public coupling point are detected at a first moment, and active power P1 of the public coupling point at the first moment is obtained through the Vp1 and the Ip1; a second voltage Vp2 and a second current Ip2 of the public coupling point are detected at a second moment, active power P2 of the public coupling point at the second moment is obtained through the Vp2 and the Ip2, and the absolute value of the difference of the P1 and the P2 is larger than the first preset value; the grid impedance ratio is obtained through the Vp1, the Ip1, the Vp2 and the Ip2; a first inverter is controlled to output first reactive power Q1, and Q1=K*P11; the P11 is active power currently output by the first inverter; a second inverter is controlled to output second reactive power Q2, and Q2=K*P12; the P12 is active power currently output by the second inverter. The method is simple, the real-time request of communication is not high, and the inverters do not need to be controlled in real time to conduct reactive power adjustment; the reactive power output by the inverters needs to be adjusted only when the grid impedance ratio changes.