108results about How to "Good current equalization effect" patented technology

The invention discloses an improved droop control method based on a communication network for a distributed power source in a parallel connection operation mode in a micro power grid system. The defect of a traditional droop control method is overcome, the performance of the distributed power source in the parallel connection operation mode is improved, the stability of the system is improved, and the improved droop control method is suitable for control over the parallel connection operation mode in the micro power grid system which integrates with new energy resource distributed power generation. According to the improved droop control method, a communication network is used as the basis, a central controller in the micro power grid system and controllers of all inverter units form an entire control system, the active power and the reactive power of public loads are calculated, and the droop control scheme of each distributed power source is corrected. The scheme is used, a better power flow equalizing effect can be achieved, smaller deviation of busbar voltage frequency and amplitude is achieved, and a good application prospect is achieved.

The invention discloses an inverter parallel system and a control method thereof; the inverter parallel system comprises an integrated controller and a plurality of inverters having different DC ends, wherein AC ends of the inverters are connected in parallel so as to serve a system output end; the integrated controller is connected with a control module of each inverter; the inverter parallel system uses an indirect integrated control mode; the integrated controller generates a synchronic signal; the control modules of each inverters use a communication quantity and current sharing controller to realize current sharing control based on pqr coordinate change. Compared with an existing indirect integrated control mode, the system and method omit a phase-locking loop so as to prevent current sharing errors caused by differences of phase-locking loops of each inverter; the control strategy of the application can provide very good current sharing effects brought by three-phase four-line parallel system with unbalanced load.

The invention relates to a novel multi-path LED passive current-equalizing circuit. The novel multi-path LED passive current-equalizing circuit comprises an LLC (logical link control) converter, and is characterized in that the LLC converter provided with a first secondary winding, a second secondary winding, a first group of output current-equalizing circuits and a second group of output current-equalizing circuits is capable of realizing output of equalized current of four paths of LED strings; and a provided four-path passive equalized current outputting strategy based on the LLC converter can be developed to 2N random paths of equalized current output for different output voltage. The novel multi-path LED passive current-equalizing circuit has the advantages of simplicity, good current equalizing effect and the like. The invention further provides an LED driving power source utilizing the novel multi-path LED passive current-equalizing circuit.

The invention discloses a DC micro-grid improved multi-gradient droop control system and a DC micro-grid improved multi-gradient droop control method with multi-grade bus voltage compensation. For radically setting bus voltage deviation caused by a droop coefficient, load current is divided into three areas, namely a light load area, a rated load area and a heavy load area. Then improved droop control is performed on the different load areas, thereby improving current sharing performance and furthermore reducing the bus voltage deviation caused by droop. According to an improved droop control strategy, an output characteristic curve of each bus voltage control unit is different from that on the condition of a traditional constant droop output characteristic. In the rated load area and the heavy load area, not only is relatively high droop coefficient realized for overcoming a current sharing problem caused by line impedance, but also multi-grade compensation module voltage reference is added according to the load amount for reducing the micro-grid bus voltage deviation, and therefore a problem of contradiction between current sharing and the voltage deviation caused by droop control can be radically controlled.

This invention discloses a SPWM inversion supply automatic master-slave parallel control method applying transient reactive power theory and parallel inversion supply output power performance, that is to control the output active power by converting frequency of its output voltage to control the output reactive power by converting its amplitude so as to uncouple the output active power P and reactive power Q to control the invented power source frequency/phase and amplitude. Although the system exists interlink signal line, the signal transferred by it is DC which can conveniently suppress interference of long distance transmission, so, the automatic master-slave control way is available in the distributed generation and UPS systems.

The invention relates to an LED drive power supply employing non-isolated multi-path passive current balancing. The LED drive power supply comprises a half-bridge LCL resonance network, a current balancing network and an LED lamp load circuit, wherein the LED lamp load circuit comprises 2N paths of LED lamp loads; the half-bridge LCL resonance network achieves current balancing output of the 2N paths of LED lamp loads through the current balancing network; and N is a natural number greater than or equal to 2. 2N paths of passive current balancing output circuits based on the half-bridge LCL resonance network can achieve current balancing output for four paths or any 2N paths of LED lamp loads which are the same or different in quantity. The LED drive power supply has the advantages of being simple in structure, high in efficiency, good in current balancing effect and the like.

The invention relates to a multistage heat insulating fixed bed reactor which can solve the defect of present one that worse gas mixed function of pipe feed distributor between stages. The invention utilizes an activator bed inside the reactor and a section gas mixed device. Wherein, said section gas mixed device comprises an inlet (9) of first material, a cylinder (4) of reactor; an inlet (6) of second material, a conical body (10), a straight pipe (11), a lateral annular space (12) and a screen plate (13), which can solve aforementioned problem effectively. The invention has the advantages of simple structure, lower pressure drop, fast uniform mixing of two flows of material and uniform material distribution. And it can be used to produce ethylbenzene with benzene and ethane via the process of alkylation, in the industrial production.

The invention discloses a heat exchanger flow equalizer which comprises a heat exchanger and an air return box. An air outlet is formed on the lower side of the air return box. A flow equalizing plate is disposed between the heat exchanger and the air return box. The flow equalizing plate is divided into at least two difference areas. A plurality through holes allowing air flow to pass are formed in each area, and the size and/or distribution density of through holes decrease gradually from top to bottom. The heat exchanger flow equalizer has the advantages that the uniformity of the internal flow fields of semiconductor equipment microenvironments, the air flow circulating the heat exchanger is equalized, the utilization rate of the heat exchanger is increased, and the heat exchanger flow equalizer is small in space occupation, good in equalizing effect, simple in structural design, adjustable, and the like.

The present invention relates to a multistage laminar heat-insulating fixed bed reactor. It is characterized by that in said multistage laminar heat-insulating fixed bed reactor a technical scheme of that utilizing predistributor to treat inlet fluid and utilizing distributor to treat interstage fluid can be adopted so as to make its interlaminar fluid distribution be uniform and make interstage fluid mixing length be shortened.

The invention discloses a method for controlling a parallel power generation system. The controlling method comprises the steps that: an amplitude limiting unit is added to a control channel on the double closed-loop foundation of a traditional voltage outer loop and a current inner loop; output values of a voltage regulator are processed via the amplitude limiting unit into output current set values; amplitude limiting values of a slave-module amplitude limiting unit are dynamically adjusted; when a main module normally operates, the amplitude limiting values of the slave-module amplitude limiting unit are equal to the output values of the main module amplitude limiting unit; the output current set values of the main module and the slave module remain the same to realize the synchronous operation of the main module and the slave module and to reach the current-sharing control. When the main module is broken down, a module having the lowest output current reference value is confirmed into the main module to realize the main-slave switch.

The invention discloses a multi-level cascading inverter with coupling inductors, wherein N inversion units are connected in parallel; each single-phase H bridge is corresponding to one coupling inductor; N is greater than or equal to 2, and N is a natural number; the upper bridge arms on the left bridge arm side of the same single-phase H bridge inversion unit are first power switch tubes; the lower bridge arms on the left bridge arm side of the same inversion unit are second power switch tubes; the upper bridge arms on the right bridge arm side of the same single-phase H bridge unit are third power switch tubes; the lower bridge arms on the right bridge arm side of the same single-phase H bridge unit are fourth power switch tubes; the first power tubes, the second power tubes, the third power tubes and the fourth power tubes are all insulated gate bipolar transistors (IGBT); and the N coupling inductors are connected through cyclic symmetrical structures. According to the multi-level cascading inverter with the coupling inductors, the loop current among the branch circuits can be effectively restrained under a condition of not requiring a complex current-sharing control method; and under the condition of the same parallel-connection common-mode inductance, the multi-level cascading inverter has the advantages of high difference mode current-sharing inductance, good current-sharing effect, small apparatus volume, and the like.

The invention discloses a distributed control method for parallel operation of frequency converters. The distributed control method comprises three parts including application of a parallel system, synchronous control and current sharing adjustment. The distributed control method proposed by the invention is simple to implement, and can obtain good dynamic and static parallel operation characteristics; in a working range of 20-50 Hz, better current sharing performance can be obtained at different frequencies and during frequency variation; and parallel modules only need to be connected by means of two sets of synchronization and current-sharing signal buses to form the distributed parallel system. Theoretically, any number of frequency converters can be connected in parallel; and the synchronization signals are generated by means of frequency integral signals, and have good anti-interference performance.

The invention provides a multi-phase interleaved Boost convertor. An output end of a generator is rectified through a rectifying circuit and is connected with input ends of Boost circuits and auxiliary power supply respectively, wherein the auxiliary power supply supplies working voltage to a sequence circuit and a control circuit; a signal output end of the sequence circuit is connected with a signal input end of the control circuit; the signal output end of the control circuit is connected with signal input ends of the Boost circuits; and the Boost circuits output voltage for use by load. By the scheme of carrying out voltage stabilization and current balancing on a plurality of Boost circuits by the plurality of interleaved Boost circuits and a voltage-stabilizing loop, the problems of high-power output and current balancing are solved; the current balancing effect is relatively good; a special current balancing circuit does not need to be designed; the input voltage range is wide; and relatively high power factor and efficiency can be obtained.

The invention discloses a multi-power-supply parallel current sharing control method based on online control. The method comprises the steps of line setting, online grouping and current sharing control. A plurality of power modules connected in parallel are uniformly connected to a control end through a control circuit in the form of a CAN bus; a required power supply module is selected from a plurality of power supply modules by the control end according to set working parameters, the power supply module is taken as a working group, a working current value of each working power supply moduleis collected in the working group during current-sharing control, then calculating is performed to obtain an average current value and a current-limiting value, and an output voltage and an output current are adjusted according to the current-limiting value. The method is rapid and concise in power supply module grouping, simple in current sharing control, good in current sharing performance, highin precision, fast in load dynamic response, stable in work and strong in anti-interference capability.

The invention discloses a current equalizing structure of a high-current rectifier bridge arm, comprising a left rectifying bridge arm and a right rectifying bridge arm, wherein the front sides and the right sides of the left rectifying bridge arm and the right rectifying bridge arm are respectively and fixedly connected with a plurality of connecting busbars from top to bottom, and one ends of the connecting busbars at the upper end and the lower end are respectively outwards bent. In the invention, one ends of the connecting busbars at the upper end and the lower end are respectively outwards bent, i.e. the lengths of the connecting busbars at the upper end and the lower end are increased, and the unbalanced condition of the whole rectifying bridge arm current is reduced, thereby a good current equalizing effect is achieved.

The invention discloses a current-sharing controller for the direct current parallel technology of a variable frequency generator set. The current-sharing controller is characterized by comprising a master control unit (MCU), a main circuit and an on-off control circuit, wherein the MCU adopts a PIC18F2320 singlechip, finishes the analogue/digital (A/D) conversion of an analogue signal, and controls a system proportion integration differentiation (PID) algorithm and pulse width modulation (PWM) output; the main circuit consists of a rectifier circuit and a filter circuit, and is connected with the on-off control circuit; the on-off control circuit comprises a power device, an over-voltage protection circuit, a signal acquisition circuit and a power device insulated gate bipolar transistor (IGBT) driving circuit; the over-voltage protection circuit is connected with the fourth pin of the MCU; the signal acquisition circuit is connected with the ninth and tenth pins of the MCU; and the power device IGBT driving circuit is connected with the twelfth and thirteenth pins of the MCU.

The invention relates to a parallel IGBT module copper bus bar installation structure. The copper bars comprises a short-connected copper bar and a switched copper bar, wherein the switched copper bar is fixedly arranged on the short-connected copper bar; at least one IGBT module is arranged on the short-connected copper bar; and a slotted hole is formed on a short-connected copper bar and between the installation positions of the switched copper bar and the IGBT module on the short-connected copper bar. The parallel IGBT module copper bar installation structure can well solve the problem of uniform flow of each IGBT module and is compact and simple.

The invention discloses a fresh air filtering device combining a negative-ion generator with a static electret. The fresh air filtering device comprises the negative-ion generator, a charging and agglomerating air pipe, an air filtering box body, a plate type static electret filter, a bag type static electret filter, a controller and a particle concentration sensor, wherein the negative-ion generator is located in the charging and agglomerating air pipe which is connected to the air filtering box body; the plate type static electret filter and the bag type static electret filter are located inthe air filtering box body; and the controller is separately connected to the negative-ion generator and the particle concentration sensor. According to the fresh air filtering device disclosed by the invention, the particles are charged and agglomerated in the charging and agglomerating air pipe and double static filtration is carried out through the plate type static electret filter and the bagtype static electret filter, so that the particle filtration efficiency is improved effectively, and meanwhile, the filtration resistance is reduced greatly.

The invention relates to a circuit for realizing automatic current equalization of a parallel power supply module, comprising: a voltage control loop used to feed the output voltage of the power supply module back to a power supply module control circuit; a current sampling unit, connected in series on a power supply output loop to sample the output currents of the power supply module. And the voltage control loop is also used to convert the output current of the power supply module into a voltage signal and feed the voltage signal to the power supply module control circuit so as to control the output voltage of the power supply module to change with its output current. The circuit of the invention can realize soft output property of the power supply and achieve automatic current equalizing ability, and has the advantages of low system cost, simple circuit, low power consumption, good current equalizing effect, ability to assure power supply reliability, and good effect on a high voltage output module.

The invention relates to a method and a device for implementing uniform flow of steam in a boiler barrel. An inverted T-shaped steam flow equalizing pipe bundle is arranged at the upper part inside the boiler barrel and a plurality of openings are non-uniformly distributed on steam flow equalizing pipes (horizontal parts), so that the steam uniformly flows upwards to enter the flow equalizing pipes and then is led out of the boiler barrel; opening apertures or opening densities along the lengths of the flow equalizing pipes are calculated and determined according to static pressure distribution design of the steam in the flow equalizing pipes in the flowing process and the steam from a steam space of the boiler barrel to the flow equalizing pipes uniformly flows upwards, so that the disadvantage that water is carried in the steam is avoided. The invention aims to avoid the phenomenon that the water surface of saturated water in a middle region of the boiler barrel is upsurged, and fundamentally eliminate the problem that water is carried in the output steam, so that operation reliability of steam generation equipment is improved.