32results about How to "Current balance" patented technology

The invention discloses a light-emitting diode current balance circuit, and belongs to the technical field of light-emitting diode driving. The light-emitting diode current balance circuit comprises a reference current generator, a current mirror and a voltage compensation circuit. The reference current generator provides reference current with a robust power voltage disturbance resistant characteristic for the current mirror to generate absorption current to each lamp string, and a framework used in the current mirror is not influenced by a transistor gain ratio, so the current mirror can stably control the current flowing through each lamp string. The voltage compensation circuit detects the voltage at end points of each lamp string so as to compensate forward conduction voltage drop. Lamp strings with different forward conduction voltage drops can be lightened, and the current flowing through the lamp strings is more balanced. In addition, a special light-emitting diode (LED) controller is not needed, and the light-emitting diode current balance circuit is low in cost and competitive.

The invention relates to a current feed circuit and a current control circuit of a light emitting diode. The current feed circuit is used for driving a first group and a second group of light emitting diodes, and the invention comprises a main power source rectification circuit, a primary DC-DC converting circuit, a first current control circuit and a second current control circuit, wherein the primary DC-DC converting circuit is used for respectively converting rectification input voltage into a first and a second pulsewidth modulating voltage; the input end of the first current control circuit is connected with the first output end of the primary DC-DC converting circuit, and the output end of the first current control circuit is connected with the first group of light emitting diodes; and the input end of the second current control circuit is connected with the second output end of the primary DC-DC converting circuit, and the output end thereof is connected with the second group of light emitting diodes. The first current control circuit and the second current control circuit respectively receive the first and the second pulsewidth modulating voltage so as to generate a first and a second currents with specific current values. The invention can reduce the integral cost of the circuits, increase the density and the running efficiency of the circuits, ensuring the currents of the light emitting diodes to be balanced and ensuring the brightness to be identical.

A polyphase power supply protection circuit. The polyphase power supply protection circuit includes a temperature detection circuit, a controller and a pulse width modulator, wherein the temperature detection circuit transmits detected temperature to the controller, the controller takes the average of received temperature values, the temperature values detected by the temperature detection circuit are compared with the average value, a deviation value is obtained, an absolute value of the deviation value is compared with a preset value, and the controller outputs a control signal to the pulse width modulator according to a comparison result. The pulse width modulator outputs a plurality of pulse width modulating signals having different duty ratios according to the control signal output by the controller to adjust supply circuits, thereby avoiding frequent adjustment of current of a polyphase power supply in the prior art, and ensuring stability of the polyphase power supply.

The invention provides a series compensation application method for changing operating modes, the application method includes the following steps of determining the maximum capacity of series compensation added to lines; adjusting access levels of power transmission channels, power supplies and loads in near regions, and analyzing the influence of reduced series compensation degrees on load flow distribution and power transmission abilities; determining the subsection number and capacity of the series compensation degrees; and analyzing the influence of the series compensation on voltage distribution of a power transmission system and transient stability when the series compensation is accessed to the system in subsections, and determining a series compensation application solution. According to the series compensation application method for changing the operating modes, when the series compensation is applied in the power transmission system, the compensation degrees of the series compensation can be flexibly changed, each stage of the compensation degrees can be stably operated for a long time, various operating modes of power supply changes and load changes can be adapted, the load flow can be effectively balanced, the power transmission capacity of the channels is improved, the function of the series compensation is fully exerted, and the construction investment efficiency of the power transmission channels and the series compensation device is maximized.

The invention relates to a mixing and flow-homogenizing structural body, which includes a pore plate flow-homogenizing layer and a foam metal flow-homogenizing layer which are arranged vertically to the gas flow direction. The pore plate flow-homogenizing layer is composed of a pore plate flow-homogenizing layer fixed sheet and a pore plate flow-homogenizing layer movable sheet, which are arranged adjacently to each other. A plurality of flow-homogenizing pores are formed in corresponding positions on both the pore plate flow-homogenizing layer fixed sheet and the pore plate flow-homogenizing layer movable sheet. The pore plate flow-homogenizing layer movable sheet can slide transversally and vertically at short distance, and when the movable sheet slides, the overlapping ratio of the flow-homogenizing pores in the movable sheet and the corresponding flow-homogenizing pores in the fixed sheet is changed. By means of the combined structure of the foam metal flow-homogenizing layer and the pore plate flow-homogenizing layer. The overlapping ratio of the flow-homogenizing pores in the movable sheet and the fixed sheet can be adjusted, thereby greatly improving flow-homogenizing effect. When being used for removal of NOx through ammonia process under large flue gas load status, gas flows and pressures in multiple chambers can be equalized, and gas flow distribution in single chamber is uniform. Meanwhile, mixing uniformity of ammonia gas or a thermal-desorption gas with flue gas is improved.

The invention discloses a full-bridge LLC circuit. The full-bridge LLC circuit comprises a first module and a second module, wherein each of the first module and the second module comprises a switch bridge arm, a resonant bridge arm, a resonant inductor, a resonant capacitor, a transformer and a rectifier unit. The resonant capacitor in the first module and the resonant capacitor in the second module are connected, so that currents flowing through the resonant inductor of the first module and the resonant inductor of the second module are balanced, current peaks of secondary side output ends of the transformer are consistent, so that currents flowing through the resonant inductors in the full-bridge LLC circuit are balanced and the current peaks of the secondary side output ends of the transformer are consistent, and the MOS in the resonant groove is not burned.

The invention relates to the technical field of power equipment, in particular to a multi-port power electronic transformer topological structure and an AC/DC microgrid system thereof, and the multi-port power electronic transformer topological structure comprises at least two alternating current input ends; at least two groups of voltage conversion units, correspondingly connected with the alternating-current input ports, each group of voltage conversion units comprising a preset number of voltage conversion subunits, and each voltage conversion subunit outputting direct-current voltages of at least two voltage classes; the direct-current voltage output ends of the same voltage class in each group of voltage conversion units being connected in parallel to form a first direct-current voltage output end of each group of voltage conversion units; at least two groups of direct-current voltage output ends, comprising second direct-current voltage output ends formed by connecting the firstdirect-current voltage output ends of the at least two groups of voltage conversion units in parallel; and at least one group of AC voltage output ends connected with the second DC voltage output end.And high-voltage, low-voltage, alternating-current and direct-current ports are provided, so that flexible networking can be realized.

The invention discloses a thin power module suitable for high frequency application. The thin power module comprises a thermal base plate, copper clad substrates and chips; the chips are connected with each other and connected with copper sheets through bonding wires; the front surface of the module is provide with an output terminal, a positive pole power terminal and a negative pole power terminal; the back surface of the module is provided with signal terminals; the chips are divided into an upper arm group and a lower arm group; upper arms and lower arms are in bilateral symmetry; each armincludes an even number of parallel-connected power units, wherein the power units are in longitudinal symmetry; each of the positive pole power terminal and the negative pole power terminal is provided with two pins; the pins of the terminals are in bilateral symmetry; the two pins of each power terminal are welded onto the copper sheet of the copper clad substrate in a longitudinal symmetry manner; and the power terminals are of bent vertical stack structures in the module. Whit the above structure adopted, the thickness of the power module can be reduced, and distributed inductance can bereduced and equalized.

The invention discloses a heat accumulating type electric heating optimal configuration method considering power flow balance of a power distribution network, which comprises the following steps of: calculating hourly heat load demand of the whole heating season according to historical air temperature and solar radiation data, and processing the uncertainty of the heat load demand by adopting a scene reduction method; establishing a heat accumulating type electric heating multi-target double-layer optimization configuration model; solving by adopting a multi-target particle swarm optimization algorithm to obtain a series of Pareto solution sets; the weight of each target value is determined through information entropy, and the schemes are sorted by using an approximate ideal solution sorting method to select an optimal compromise solution from the schemes; according to the method, unreasonable distribution of power flow in the line is improved, overlarge voltage offset is adjusted, the problem that the voltage is too low and even the voltage is out of limit due to access of the electric heating load is solved, it is guaranteed that the voltage quality meets the requirement, and a power distribution network can operate safely and stably.

The invention provides an integrated power supply network architecture for a railway power system and a cooperative control method thereof. The integrated power supply network architecture is characterized in that the integrated power supply network architecture comprises a traction transformer, an uplink power supply arm, a downlink power supply arm, a left-right migration type energy router EMR, a railway power supply and distribution network and a network interconnection type backbone router NCBR, wherein the traction transformer and the uplink and downlink power supply arms supply power to up and down trains; the EMR is used for connection of the uplink and downlink power supply arms of the same traction transformer and connection of power supply arms between different traction transformers; and the NCBR is connected with a railway traction 27.5-kV power supply network, realizes conversion into a three-phase three-wire 10-kV or 35-kV power supply, is connected to the railway power supply and distribution network and supplies power to loads in the railway power supply and distribution network. According to the invention, the cooperative operation of the integrated power supply network architecture of the railway power system is realized through traction state, a braking state and power supply state control.

The invention discloses an energy preine saving purifying AC stabilizied-voltage power, it includes: power switch, panel, power light, output power line connection end, filter and transformer circuit, photoelectric inspection circuit, sampling and comparing circuit, controlling circuit, overvoltage crowbar, compensating and optimizing circuit, when it is used in two-phase circuit, the compensating and optimizing circuit is composed of two equipments, each one has two magnetic sheet capacitance, a setting ruler capacitance, an inductance, an unilateralism controllable silicon, three resistances, an indicator light and a voltage dependent resistor, the two compensating and optimizing circuits have symmetrical style and different value, and are formed a strong against weak complementary circuit. The compensating and optimizing circuits can achieve the intention of stabilizing voltage, saving energy by absorbing and releasing energy.

The invention belongs to the field of semiconductor packaging and power modules, in particular to an integrated IGBT packaging structure based on DBC layout. The structure comprises a three-phase DBCstructure. A frame is fixed outside the three-phase DBC structure, a plurality of chips are welded on the front surface of the three-phase DBC structure, the back surface of the three-phase DBC structure is directly welded on the radiator, the chips in the three-phase DBC structure are connected with one another, and a laminated busbar is connected to a direct-current terminal of the three-phase DBC structure. The three-phase DBC is directly welded to the radiator, and compared with a traditional process, one layer of substrate is omitted in the process, so that the thermal resistance is greatly reduced, and the power density is improved; and meanwhile, the process is convenient to realize automatically, and the production efficiency is improved.

The invention discloses a three-phase automatic balancing device with reactive compensation, which is arranged between a load and a transformer and comprises an acquisition unit, a control unit and apower unit. The acquisition unit is connected with the signal input end of the control unit; the control unit is connected with the control end of the power unit, and the power unit is electrically connected with the wire inlet end of the load through an electric reactor; the acquisition unit comprises a current transformer and a voltage transformer; the control unit comprises a DSP main control chip and an FPGA signal generator, and the power unit comprises an H-bridge type multi-level circuit composed of a plurality of insulated gate bipolar transistors; the current transformer and the voltage transformer are connected with the signal input end of the DSP main control chip; the DSP main control chip is connected with the control end of the H-bridge type multi-level circuit through the FPGA signal generator, and the H-bridge type multi-level circuit is connected with the wire inlet end of the load through the reactor so as to output three-phase imbalance compensation currents. The device can automatically solve the problem of unbalanced three-phase loads, manual intervention is not needed, and worry and labor are saved.

The invention discloses an automatic power factor compensation device for double-coil power frequency induction connected furnaces, which comprises a sensor, a PLC controller and an actuator controller. The sensor is used for collecting the parameters of three-phase electricity. The output terminal of the sensor is connected with the PLC controller. The output terminal of the PLC controller is connected with the input terminal of the actuator controller. The output terminal of the actuator controller is connected with a plurality of contactors, each of which correspondingly controls the switching of one set of compensation capacitors. The compensation capacitors are used for making compensation for the three-phase electricity. The advantage is that capacitor switching is automatically controlled by detecting data, so that the change of a double-coil connected furnace between two gears is satisfied, the device can better adapt to connected furnaces, and inter-phase current balance and power factor compensation are achieved during working of connected furnaces.

The embodiment of the invention provides a microgrid system. The microgrid system comprises: a plurality of microgrid subsystems; each microgrid subsystem comprises a direct current microgrid and at least two flexible substations; each flexible substation comprises: a high voltage alternating current system, a high voltage direct current system, and a low voltage direct current system, wherein thehigh voltage alternating current system and the high voltage direct current system are connected, the high voltage direct current system and the low voltage direct current system are connected, and the high voltage alternating current system and the low voltage direct current system are connected; each direct current microgrid includes: a high voltage direct current bus and a low voltage direct current bus; the plurality of microgrid subsystems are interconnected into a loop by the high voltage direct current buses; the high voltage direct current buses are connected to the high voltage direct current systems; and the low voltage direct current systems of the flexible substations in the microgrid subsystems are connected through the low voltage direct buses. Load transfer and looped network current equalization can be ensured, and the continuous power supply capability of the distribution network is ensured.

The electric connector with the function of resisting spark-over includes an insulator and a central terminal, several conducting terminals, several switch terminals and a connector which are placed in the insualtor. The front end of every switch terminal possesses pick-up portion, and the pick-up portions of all switch terminals are properly spaced on the axial direction of electric connector, and the central terminal is electrically connected with connecting body, and between the switch terminal and connector there is an insulating block for separating them. When the butt-joint connected is inserted, the butt-joint connector is electrically connected with central terminal fistly, then all the switch terminals are started successively, and the connector and the conducting terminals are contacted one after another so as to implement electric connection.

The present invention provides a LED current balancing circuit. The LED current balancing circuit comprises: a first light emitting diode assembly; a second light emitting diode assembly reversely arranged with the first light emitting diode assembly and connected in parallel with a first common connection point; a third light emitting diode assembly reversely arranged with the second light emitting diode assembly and connected in parallel with a second common connection point; an alternating current power supply generator configured to provide the current required to the first power light emitting diode assembly, the second light emitting diode assembly and the third light emitting diode assembly for brightness and connected with the first light emitting diode assembly and the third light emitting diode assembly; a first current sharing element connected between the alternating current power supply generator and the first common connection point to balance the current received by the first and the second light emitting diode assembly; and a second current sharing element connected between the alternating current power supply generator and the second common connection point to balance the current received by the second light emitting diode assembly and the third light emitting diode assembly.

The invention discloses an intelligent circuit breaker for frequent switching of an impact load and a control method thereof. The intelligent circuit breaker comprises a voltage transformer, a current transformer, a temperature measurement module, an impact load compensation module and a control system; and the voltage transformer is connected to the three-phase four-wire in parallel, the current transformer is connected to the three-phase four-wire in parallel, the temperature measurement module is connected to the three-phase four-wire in parallel, the impact load compensation module is connected to the A phase, the B phase and the C phase in the three-phase four-wire in series, and the circuit breaker and the control method thereof have high impact load bearing capacity.