55results about How to "Realize reactive power compensation" patented technology

The invention discloses a single-stage boosting / reducing energy storage type photovoltaic grid-connected power generation control system, which comprises an energy storage type power conversion main circuit and a control system which are connected mutually. The energy storage type power conversion main circuit comprises a photovoltaic cell, an inductance and capacitance circuit network, an energystorage cell and a three-phase inverter which are connected mutually; and the control system is used for performing charging and discharging management on the energy storage cell, maximum power tracking and threshold control on the photovoltaic cell and closed-loop control on output active and reactive power of the three-phase inverter. The system finishes boosting / reducing, inversion and energy storage through single-stage power conversion, realizes the minimum inverter capacity with a simple structure, ensures the steady power of the power grid, can collect solar energy to the greatest degree, improves the power generation efficiency, realizes reactive compensation, electric peak regulation control and the like, and improves the quality of the power grid.

A voltage reactive power fast control method for the wind power station of a variable-speed constant-frequency wind-power machine group, which comprises the following steps: 1, converting the voltage of an access node of the wind power station; 2, judging and selecting a reactive control mode; 3, establishing a reactive compensation scheme of the wind power station; 4, establishing a reactive compensation distribution scheme of the wind-power machine group; 5, sending a reactive control command; 6, triggering the next control by judging and controlling timelag. The method takes the voltage of the access node of the wind power station as an object of regulation and control; takes the steady-state operation voltage of the access node of the wind power station as a target of regulation and control; comprehensively considers the coordination between the wind power station and an electric network to carry out uniform planning of the reactive compensation of the whole wind power station, so as to lead all the machine groups in the wind power station to be capable of reasonably adjusting the reactive power, thus ensuring the reactive compensation of the whole station to be sufficient, preventing the wind-power machine group from acting frequently under the situation of real time changing of the voltage of the electric network, realizing reactive fast control and being help for maintaining the voltage stabilization of the electric network of an access area.

The invention discloses a parallel three-phase grid-connected inverter adopting mutual reactors and a control method for the three-phase grid-connected inverter, and belongs to the technical field of power grid inversion. The inverter overcomes the shortcomings of large volume, high weight, high cost, low efficiency, narrow application range, control complexity, low reliability and the like of the conventional parallel grid-connected inverter. According to the inverter, two sets of three-phase grid connected inverters are connected in parallel, and a capacitor is connected in parallel with a direct current bus which is shared by the two sets of three-phase grid connected inverters; and the two in-phase alternating current signal output ends of the two sets of three-phase grid-connected inverters are connected together after passing through a set of mutual reactor respectively, and are connected with a power grid. According to the three-phase grid-connected inverter, the two sets of three-phase grid-connected inverters with the same structure are coupled with each other by the mutual reactors; and for each three-phase grid-connected inverter, a d-axis component and a q-axis component are coupled with each other, and in order to eliminate the influence, a feed-forward decoupling control strategy and a current loop are adopted in the control method.

The invention discloses compensation devices in magnetic induction type wireless electric energy transmission equipment, and compensation methods thereof. The main structure of a receiving compensation device is as follows: multiple receiving compensation capacitors are connected in parallel to form a receiving compactor compensation array, wherein the receiving compensation capacitors in the receiving capacitor compensation array are respectively connected with corresponding receiving electronic switches in series; the receiving capacitor compensation array is connected in series between a receiving coil and a load of a receiving end of the magnetic induction type wireless electric energy transmission equipment; the receiving coil of the receiving end is provided with a receiving current sensor, and the two ends of the load of the receiving end are provided with a receiving voltage sensor; and the control end of each receiving electronic switch of the receiving capacitor compensation array, the output end of the receiving current sensor and the output end of the receiving voltage sensor are connected with a receiving compensation controller. By using the devices and methods provided by the invention, the magnetic induction type wireless electric energy transmission equipment can be enabled to resonate within a rated frequency, the active power of the transmission equipment is improved, and accordingly the transmission power and transmission efficiency of the equipment are improved.

The invention discloses a power grid reactive power compensation method and device and a grid-connected inverter. The power grid reactive compensation method comprises the following steps of detecting the voltage of a power grid, when the voltage magnitude of the detected voltage is lower than the preset normal voltage magnitude, determining the electric reference parameters corresponding to the voltage; determining the current pulse width modulation (PWM) mode according to the electric reference parameters corresponding to the voltage, wherein the PWM mode comprises a unipolar modulation mode and a bipolar modulation mode; and outputting reactive power by utilizing the current PWM mode, so as to realize reactive compensation for the power grid. In the scheme provided by the invention, when the voltage of the power grid drops, the current PWM way is determined by the electric reference parameters corresponding to the detected voltage, thus, the unipolar modulation way and the bipolar modulation way are effectively combined in a current period; when the voltage of the power grid drops, the reactive power compensation can be effectively carried out for the power grid, and the switching losses and inductance losses can also be reduced.

The invention provides a novel power quality regulator on the background of a micro-grid aiming at a power quality management problem in the micro-grid. According to the novel power quality regulator on the background of the micro-grid, a distributed power source and energy storage elements are added on the basis of an original parallel connection mixed type active electricity filter, an improved type id-iq compound directive current detection and combining implement method are adopted, and demand that one machine is provided with a plurality of functions is met. According to the novel power quality regulator on the background of the micro-grid, harmonic wave and reactive current compensation of the micro-grid are effectively solved, at the same time, grid-connection generating functions of distributed power source are well achieved, and governance cost of the power quality of the micro-grid is saved to the greatest extent. Simulation and experiment operating data show that the design scheme is effective and reliable.

The application discloses a power grid adaptability test device. The power grid adaptability test device comprises a turbulence power supply device, a turbulence circuit switch and a bypass switch, and is characterized in that the turbulence power supply device comprises a phase-shifting transformer, a four-quadrant converter and a main controller; the main controller is connected with the phase-shifting transformer and the four-quadrant converter respectively; the phase-shifting transformer comprises a first voltage transformer, a first current transformer and a second voltage transformer and a second current transformer which are connected with the main controller respectively; the four-quadrant converter is of a three-phase cascaded topological structure, and each phase consists of 30 cascaded power conversion units; each power conversion unit comprises a rectifying end, a main control end and an inverting end. By adopting the power grid adaptability test device provided by the application, the problem that power energy supplied to a conventional test device is low in quality can be solved effectively.

The invention discloses an MMCC (modular multilevel cascade converter) direct railway power compensator and a control method thereof. The MMCC direct railway power compensator adopts a quadrilateral single-phase AC-AC converter structure, and each of four sides comprises a modular multilevel cascade converter and an inductor and can be directly connected with a traction power supply arm without a step-down transformer; the quadrilateral single-phase AC-AC converter is free from a direct-current link in a process and can be used for achieving bidirectional power conversion and flow and compensating reactive power and harmonic waves of two traction power supply arms. Meanwhile, the invention discloses a comprehensive voltage and current control method for the MMCC direct railway power compensator, and the method can be used for achieving quick response of an output current, keeping stable and balanced direct-current side voltage and effectively improving the control performance of a system.

The invention relates to an industrial steam turbine asynchronous power generation-based energy-saving system and an energy-saving control method. The system comprises a temperature and pressure reducer and at least one back pressure type steam turbine generator unit, wherein the temperature and pressure reducer is connected with a medium- and low-pressure steam incoming main pipe; an inlet steampipeline system is arranged between the temperature and pressure reducer and the medium- and low-pressure steam incoming main pipe; an outlet steam pipeline system is arranged between the temperatureand pressure reducer and a steam using device; the back pressure type steam turbine generator unit is connected with a temperature reducing device; the temperature reducing device is connected with the inlet main pipe of the steam using device; each pipeline is provided with a manual or electric regulating valve; the temperature and pressure reducer, the back pressure type steam turbine generatorunit, the steam using device, each electric regulating valve are controlled by a DCS / PLC automatic control system; steam enters the back pressure type steam turbine asynchronous generator unit; and the unit does work and generates power through the impact steam. With the system and method of the invention adopted, cost can be saved; and a construction period and project cost are 1 / 2-2 / 3 of those of a synchronous unit with the same installed capacity as the system of the invention. The system and the method can be suitable for common industrial fields such as the phosphorus compound fertilizerchemical industry, the petrochemical industry, the smelting metallurgy industry, the papermaking light textile industry and the like.

The invention belongs to the technical field of electric energy quality management of electric power systems, particularly relates to an electric energy quality comprehensive control device, and aims at providing an electric energy quality comprehensive control device for a power distribution network. The electric energy quality comprehensive control device for the power distribution network integrates the functions of reactive compensation, harmonic compensation, unbalance compensation and low voltage compensation. According to the technical scheme, the electric energy quality comprehensive control device for the power distribution network is connected between a power supply U1 and a load FZ1 in series; the electric energy quality comprehensive control device comprises a main circuit and a control circuit, and the main circuit comprises a transformer TR, a filter component LC, a filter reactor La, a first three-level inverter CON1 and a second three-level inverter CON2. The electric energy quality comprehensive control device is suitable for electric power systems.

The invention provides a reactive compensation cabinet and a control method for reactive compensation units of the reactive compensation cabinet. The control method comprises the following steps: starting the reactive compensation cabinet; each reactive compensation unit being in information interaction with other reactive compensation units, and a control unit of each reactive compensation unit comparing information of itself with the received information of the other reactive compensation units; judging the priority of each reactive compensation unit based on the information; if the priority of the ith reactive compensation unit is larger than the priority of the other reactive compensation units, taking the ith reactive compensation unit as a master machine and the control unit of the ith reactive compensation unit as a master control unit, and taking the other reactive compensation units as slave machines and the control units of the other reactive compensation units as slave control units; and the master control unit controlling the master machine and all the slave machines to be in reactive power operation so as to realize reactive compensation of the reactive compensation cabinet. The master control unit does not need to be configured separately, and only one master machine runs every moment; and the reactive compensation of the reactive compensation cabinet is realized.

The invention discloses a three-phase unbalance compensation apparatus based on fuzzy PI control. The apparatus herein includes a positive sequence compensation network, a negative sequence compensation network and a control module. The positive sequence compensation network brings an inverter AC side voltage source u<c0(1)> and a system side voltage source us through an inverter equivalent resistor R and a series reactor L. The negative sequence compensation network brings an inverter AC side voltage source u<c0(2)> into connection with the inverter equivalent resistor R and the series reactor L. The positive sequence control and the negative sequence control are under overlapping control. The positive sequence control uses ([Theta]<1>-[phi]<1>) uses indirect current control. The negative sequence control uses ([Theta]<2>-[phi]<2>) phase and modulation ratio to control negative sequence current and phase. The PI control module uses fuzzy rules and a fuzzy inference module to perform control so as to realize reactive compensation and three-phase load balance of a power distribution network.

The invention relates to a novel electrochemical capacitor. The electrochemical capacitor comprises a microprocessor, a capacitor temperature detection circuit, a zero crossing detection circuit, a BL8203, a pulse transformer, an SPI bus, a power failure detection circuit, a human-machine interaction interface module, a 485 communication circuit, a first RJ45 communication port, an electric energy measurement circuit, a second RJ45 communication port, an electric current signal sensing circuit and a combination switching circuit. According to the novel electrochemical capacitor provided by the invention, the latest achievements of microelectronic hardware and software technology, micro-sensor and micro-network technology are adopted, and are successfully applied to a low-voltage reactive compensation capacitor, and low-voltage reactive automatic control function, zero-crossing switching, power failure protection, electric energy measurement, communication networking, fault self-diagnosis and other functions are realized. The novel electrochemical capacitor can be used flexibly in various occasions of low-voltage reactive power control, changes the structure model of the existing low-voltage reactive automatic control equipment, and has the advantages of simple structure, easiness in production, cost reduction, performance improvement, and easiness in maintenance.

The invention relates to a short circuit current limiting device for harmonic suppression and reactive compensation, belonging to the technical field of fault current limiting. The short circuit current limiting device comprises a short circuit current limiting reactor, a three-phase current converter, a system power supply, a load and a high-pass filter, wherein the short circuit current limiting reactor is connected between the system power supply and the load in series; and the three-phase current converter is connected with the load in parallel through the high-pass filter. When the system works normally, the three-phase current converter is used for performing the reactive compensation and the harmonic suppression at the load side; meanwhile, the corresponding reactive power is injected through the three-phase current converter to compensate the voltage drop generated on a circuit by the short circuit current limiting reactor; when the system is in short circuit at the load side, the three-phase current converter triggers pulse through locking an IGBT (Insulated Gate Bipolar Translator) to quit the operation quickly, and the short circuit current limiting reactor plays the role of current limiting instantly. The short circuit current limiting device for the harmonic suppression and the reactive compensation has the advantage of improving the power supplying reliability and the system stability because the short circuit current is limited quickly and reliably during fault operation and the harmonic suppression and reactive compensation functions of the nonlinear load can be realized.

The invention discloses a novel NPC three-level photovoltaic grid-connected control method, which is characterized in that the method is a novel control method combining active filtering and reactivepower compensation with photovoltaic grid-connected power generation. The novel NPC three-level photovoltaic grid-connected control method adopts a quasi proportional resonance controller which does not need coordinate transformation, decoupling control and feedforward compensation, can realize zero steady-state error tracking of an AC signal in a stationary coordinate system, and completes inverter grid-connected control simply and efficiently. The novel NPC three-level photovoltaic grid-connected control method solves the inevitable problems such as complex coordinate transformation, decoupling control and feedforward compensation, realizes the zero steady-state error tracking of the AC signal in the stationary coordinate system, can effectively completes unified control of harmonic suppression and reactive current compensation while simplifying a control algorithm, realizes the functions of reactive power compensation and harmonic suppression on loads, and improves the utilization rate of a photovoltaic grid-connected system.

The invention discloses a single-phase direct-hanging AC-DC-AC converting system based on a MMC (Modular Multilevel Converter), which is formed by six MMC bridge arms in connection. P power modules with the same structures and an MMC bridge arm inductor L are connected in series to form each MMC bridge arm; the power module has a single-phase half-bridge structure and is formed by an IGBT half bridge and a DC energy storage capacitor; the six MMC bridge arms are in a three-phase connection and form two single-phase AC ports; and the two single-phase AC ports share the two MMC bridge arms in the six MMC bridge arms. The voltage phase difference of the two single-phase AC ports is 90 DEG, and the capacity of each sharing MMC bridge arm is the square root of 2 times of the capacity of the remaining MMC bridge arms. According to the single-phase direct-hanging AC-DC-AC converting system based on a MMC (Modular Multilevel Converter), voltage conversion and active power transfer between the two single-phase AC ports can be realized, the two single-phase AC ports can compensate reactive power respectively, and the system can be applied to frequency conversion occasions; a traction and matched transformer can be omitted, the occupied area and the investment can be reduced, the loss is reduced, and the efficiency is improved; and the system of the invention is advanced in technology, reliable and easy in implementation.

The invention discloses a vacuum contactor with a mixed magnetic field, which belongs to the technical field of switches and adopts the mixed magnetic field with the combination of a permanent magnetic field and an electromagnetic field for replacing the single electromagnetic field or the permanent magnetic field; and the whole structure comprises a vacuum interrupter, a permanent magnetic mechanism, a conversion mechanism, insulated pull rods, a frame, an electromagnetic mechanism, an electronic control mechanism, an armature, a spring and the like, wherein the permanent magnetic mechanism is connected with the conversion mechanism, the electronic control mechanism is connected with a closing and opening coil and an electromagnetic ring in the permanent magnetic mechanism through conducting wires, and the three-phase insulated pull rods are connected on the conversion mechanism. The vacuum contactor can avoid the open-failure of the permanent magnetic alternating vacuum contactor, realize the functions of reactive power compensation and automatic switching and lead the overall manufacturing cost to be lower.

The invention relates to a bus reactive power optimization compensation controller and belongs to the field of power equipment. The bus reactive power optimization compensation controller comprises a bus, a capacitor group and a magnetically controlled reactor group, wherein the capacitor group is arranged in parallel and connected with the bus; and the magnetically controlled reactor group is arranged corresponding to the capacitor group and connected with the bus. The bus reactive power optimization compensation controller is characterized in that: the capacitor group is connected with the bus through a fling-cut switch; and the magnetically controlled reactor group is connected with each capacitor of the capacitor group respectively through a controller. The bus reactive power optimization compensation controller has a simple and effective structure. A processing device has high calculation capacity. After a numerical value requiring reactive power compensation is calculated, the capacitor group required to be used is selected to perform capacitive reactive power compensation and inductive reactive power compensation through the magnetically controlled reactor group according to the actual condition, and the reactive power compensation for the bus can be realized without the magnetically controlled reactor group with the same capacitance as that of the fixed capacitor group. The bus reactive power optimization compensation controller has the advantages of low cost and high automation degree.

The invention relates to the field of power and particularly to an unbalanced reactive compensation intelligent capacitor and method. The unbalanced reactive compensation intelligent capacitor comprises a main control MCU processing unit, a data collection unit, a zero-cross switching control unit and a capacitor assembly composed of a separate compensation capacitor and a phase compensation capacitor; the main control MCU processing unit calculates a grid-side sampling data based on voltage and current signals and a temperature signal, then carries out an unbalanced compensation scheme preferentially based on the grid-side sampling data, then carries out a reactive compensation scheme and realizes selection of a separate compensation capacitor group or a phase compensation capacitor group through the zero-cross switching control unit, thereby realizing unbalanced compensation scheduling or reactive compensation scheduling. The unbalanced reactive compensation intelligent capacitor has the beneficial effects that separate compensation and phase compensation of the separate compensation capacitor can be realized, the compensation forms such as the compensation of a common compensation capacitor or split compensation and phase compensation mixed compensation are controlled, both the unbalanced compensation and the reactive compensation are realized, and the utilization space of the intelligent capacitor is also improved.

The invention discloses a photovoltaic flexibility grid-connection device and a control method. The photovoltaic flexibility grid-connection device comprises a support capacitance module, a voltage detection module, a program-controlled computer (PCC) module, a current detection module, a controller module, a pulse-width modulation (PWM) pulse generation module and a contravariant module. Voltage signals collected by the voltage detection module from two ends of the support capacitance module and power grid current signals of the PCC module collected by the current detection module serve as input signals of the controller module, outputs signals of the controller module serve as input signals of the PWM pulse generation module, pulse signals generated by the PWM pulse generation module are input in the contravariant module to control output of the contravariant module. The photovoltaic flexibility grid-connection device and the control method can achieve harmonic suppression and reactive compensation, can reduce impacts of load sudden change on the power grid, improve quality of photovoltaic system grid-connection current, have characteristics of the friendly power grid and are simple in control method.

The invention discloses an energy recovery device. The device comprises a frequency converter, an inverter and a three-phase power network. An inductor is arranged on a circuit at one end of the inverter, one end of the inductor is connected with a first diode, and the other end of the inductor is connected to a three-phase bridge-arm connected positive bus of the inverter; a current input terminal of the first diode is connected to a positive DC bus bar of the frequency converter, a current output terminal of the first diode is connected with the inductor; another circuit at one end of the inverter is connected with a second diode which has opposite current direction to the first diode, a current input terminal of the second diode is connected to a three-phase bridge-arm connected negative bus of the inverter, a current output terminal of the second diode is connected to a negative DC bus bar of the frequency converter, and the other end of the inverter is connected with the three-phase power network. The device is mainly used for frequency converters in need of regenerative electric power, and realizes harmonic wave control, reactive compensation and energy feedback power network control so as to achieve energy saving effect.

The invention discloses a high voltage dynamic reactive compensation device which is characterized by comprising a transformer, a three-phase capacitor group and 3n power module units, wherein 3n single-phase windings and one three-phase winding connected with the three-phase capacitor group are arranged at the secondary side of the transformer; each power module unit is provided with two input ends; control circuits for controlling the communication state between the two input ends are arranged inside the power module units; the output ends of the 3n power module units are respectively connected with 3n single-phase windings; and the control circuits can be rectification H-bridge circuits; and controllable devices are controllable one-way thyristors. By controlling the parallel power module units, the reactive compensation of a high voltage power grid is realized effectively; a mutation current can be buffered by the three-phase capacitors effectively, so that the influence of the power grid is reduced to the minimum. With the adoption of the reactive compensation device, the cost of the whole reactive compensation device is saved, the process mechanism is simplified, and the manufacturing efficiency is improved.

The invention disclosed an intelligent-microgrid-based wind power generation system comprising a plurality of wind power generation units arranged in parallel and an energy-storage bidirectional converter having an electric energy input terminal and an energy storage input terminal. All wind power generation units are electrically connected with an energy storage input terminal of the energy-storage bidirectional converter; the electric energy input terminal is connected with an energy storage system for storing the electric energy; and the wind power generation units are connected with the energy storage input terminal by an energy storage line. Besides, PCS power controllers for outputting starting voltages stably in a balancing mode and detecting initial operation powers of the wind power generation units are connected to the energy storage line of the wind power generation units and the energy storage input terminal. According to the invention, the system can be started independently by be separated from the power grid; defects of randomness and intermittency of the distributed power supply can be effectively overcome; distributed power supply access can be realized; fluctuation of the smoothing system can be adjusted in real time; the balance of power generation and load inside the grid can be maintained; and the voltage and frequency stability is guaranteed.

The invention provides a decoupling control system and method of a hybrid reactive compensation system. The decoupling control system comprises a reactive current detection circuit, a vector decoupling control circuit, a current conditioning circuit, a reactive compensator and an active compensator which are sequentially and electrically connected. With the decoupling control system and method provided by the invention, the response speed of the traditional reactive capacitor cabinet is increased, the compensation accuracy of the traditional reactive capacitor cabinet is improved, and the cost of an active module is reduced.

The invention discloses a power distribution network feeder interconnection control method based on an FMS, and belongs to the technical field of power distribution networks. Although the FMS is applied to the power distribution network in the prior art, active power flow adjustment and reactive power compensation cannot be better realized, the line loss of the power grid cannot be effectively reduced, and the upstream pressure of each feeder line of the power grid cannot be effectively relieved. The power distribution network feeder interconnection control method based on FMS comprises a multi-state switch FMS capable of realizing power flow between feeders and a voltage source type converter used for transmitting active power flow and regulating and controlling electric energy quality. According to the method, the dq coordinate system regulation and control model is established for the power distribution network, and active and reactive decoupling is carried out according to the dq coordinate system regulation and control model, so that the flexible multi-state switch FMS synchronously and independently regulates and controls the active power and the reactive power, and the FMS can synchronously realize active power flow regulation and reactive compensation of the power distribution network.

The invention relates to an electricity-saving appliance, especially to a single-phase electricity-saving appliance having functions of static var generation and active filtering and a control method thereof. The single-phase electricity-saving appliance comprises a main control portion, an electricity-saving converter circuit, and a detection circuit; and all the components can be combined or split in the terms of function or structure and are connected respectively, mutually, and electrically. And an electricity-saving converter circuit alternating-current side and a single-phase alternating-current load are directly and electrically connected in parallel or indirectly and electrically connected in parallel by an isolation transformer. Besides, the control method includes the following steps that: the electricity-saving converter circuit detects a load side power parameter in real time and provides a matched reactive power; and meanwhile, a harmonic wave generated by the load is filtered. According to the invention, a power factor of a power transmission line can be improved; and the harmonic wave generated by the load can be filtered and the power quality can be optimized. Therefore, the energy loss can be reduced and an objective of electricity saving can be achieved.

The invention discloses a low voltage reactive compensation device and a low voltage reactive compensation system. The low voltage reactive compensation device comprises main switches (3), a star-shaped unbalanced capacitance compensation circuit (4) and an angular balance capacitance compensation circuit (5). The angular balance capacitance compensation circuit (5) is connected with A phase, B phase and C phase of three-phase alternating current through three main switches (3). One end of the star-shaped unbalanced capacitance compensation circuit (4) is connected with A phase, B phase and C phase of three-phase alternating current through three main switches (3). The other end is connected with a zero line. According to the low voltage reactive compensation device and the low voltage reactive compensation system, the problem of substandard electrical energy delivery in the prior art is overcome, and substandard electrical energy reactive compensation is realized.

The invention discloses a ZigBee and RS485 communication mode based quick reactive compensation controller. The controller and an intelligent capacitance module quickly network and quickly exchange state data through the ZigBee wireless communication technology; a control instruction is distributed by RS485 communication, and the control instruction and a state acquiring instruction are performed synchronously, so that the total communication speed can be increased, and as a result, the purpose of quick compensating can be achieved. With the adoption of the controller, two communications can be performed synchronously; the control instruction and the state acquiring instruction are performed through different links, the intelligent capacitance module can be timely responded, so that the communication time can be greatly reduced, the compensation speed can be increased, and the reactive power compensation of a power grid can be quickly and effectively achieved.