231results about How to "Reduce short circuit current" patented technology

The invention discloses a process for manufacturing a solar cell by twice screen printing and grooving, which is used for manufacturing the solar cell by twice electrode printing and comprises a grooving process and a twice printing process, wherein the grooving process comprises the step of performing grooving on an electrode grid line area on the surface of a silicon wafer so as to form an etched groove in the electrode grid line area; and the twice printing process comprises the following steps of: a, primary electrode printing, namely, filling printing electrode paste into the etched groove and performing drying to form a first layer of electrode in the etched groove; and b, secondary electrode printing, namely, printing the electrode on the outer surface of the first layer of electrode so as to form a second layer of electrode in the electrode grid line area on the surface of the silicon wafer. The solar cell manufactured by the method has relatively lower series resistance, a selective emitter and relatively higher conversion efficiency, and can reduce shading loss; and the electrode paste is difficult to spread in a sintering process.

The invention discloses an electronic mutual inductor test system and a test method. The electronic mutual inductor test system comprises a standard device, a signal conversion device, an error measuring device, a test power supply, a merging unit and a tested electronic mutual inductor, wherein the standard device is used for providing a standard signal serving as a test reference; the signal conversion device is used for receiving the standard signal and converting the standard signal into an analog signal which can be acquired by the error measuring device; the test power supply is used for outputting a primary voltage and a primary current for test use; the merging unit is used for receiving a digital signal output by the tested electronic mutual inductor and processing the digital signal; and the error measuring device is used for receiving the standard signal output by the signal conversion device and the digital signal output by the merging unit, and acquiring the ratio difference and the phase difference of the tested electronic mutual inductor. The electronic mutual inductor test system is particularly suitable for a field error test of the electronic mutual inductor, andhas the advantages of convenient test work, high reliability, small equipment volume, light weight, high test result accuracy and the like.

The invention provides a method for preparing a perovskite solar cell on the basis of a two-dimensional material graphene-phase carbon nitride. The graphene-phase carbon nitride is doped into a perovskite precursor solution to prepare the perovskite solar cell. The method has the following advantages that (1) the raw material required for synthesis of the material is low in cost, and the product is small in toxicity; (2) solvent volatilization during the annealing process is effectively slowed down, so that a perovskite thin film crystal is more uniform and compact; (3) the grain crystal sizeof a perovskite layer is increased, a crystal boundary easy to combine with charge is effectively reduced, and the filling factor of a device is improved; (4) a surface of the perovskite thin film ispassivated, and the hysteresis phenomenon of the device is effectively improved; and (5) the conductivity of the surface of the perovskite thin film is improved, the contact resistance of the interface is reduced, and the short-circuit current of the device is increased. The preparation process is simple and convenient and is low in preparation difficulty; by doping of the graphene-phase carbon nitride, the smoothness and the uniformity of the perovskite thin film can be effectively improved; and by a series of gradient doping, the device performance is remarkably changed.

The invention proposes a static var compensator (SVC) and DC ice-melting device and a realization method thereof. Primary equipment comprises a thyristor rectifier, a reactor, an AC/DC filter, a disconnecting switch, a zinc oxide arrester and the like, wherein the thyristor rectifier is also taken as the thyristor controlled reactor (TCR) valve bank; the reactor is the phase-change smoothing TCR;the thyristor rectifier and the reactor are designed into the detachable structures, therefore, the thyristor rectifier and the reactor are detached and reassembled to form different topological structures by arranging the disconnecting switch between the detachable structures and operating the line disconnecting switch, so as to realize the switchover between the DC ice-melting function and the SVC function and solve the problem of the heavy-current high-voltage and high-capacity DC ice-melting device and the problem of system reactive power compensation.

The invention belongs to a device for solid-liquid separation/classification and non-homogeneous separation, specifically a hydraulic cyclone with improved structure of central post and overflow pipe. The device comprises a feed pipe, a cylindrical section, a coniform section, an overflow pipe and a hollow tubular central post with partial-spiral fins and spiral flow deflectors and provided outside the overflow pipe. The central post is a hollow tube provided thereon with a plurality of holes. The spiral flow deflectors are provided on the outer surface of the central post. The spiral fins are provided on the overflow pipe from the bottom of the overflow pipe to a height below the bottom of an inlet pipe. Compared with the prior art, the separation efficiency of the hydraulic cyclone is increased by 5-10% and the energy consumption is reduced by 20%. The hydraulic cyclone has high stability and reliability in separation efficiency and is suitable for solid-liquid separation in ore dressing, dredging, chemical and petroleum industries.

The invention discloses a high-safety lithium ion battery. The electronic conductivity of an electrode active material coating of the battery is distributed from a higher one to a lower one from the surface of a current collector to the outer surface of the coating. The distribution is realized in a multilayer coating manner, slurry of different components is selected on each layer, and the distribution of the electronic conductivity is controlled by changing the content of the conductive agent and adhesive contained in the slurry. Due to the distribution of the electronic conductivity, the short-circuit current can be reduced, and the safety is improved; meanwhile, the electronic conductivity distribution is similar to distribution of normal charging and discharging current, the conductive agent utilization rate is improved on the positive side, and more space can be reserved for the electrode active material, so that the energy density is improved.

The invention discloses a zero DC voltage fault ride-through control method of a multilevel modular converter (MMC) under an asymmetric state of bridge arm parameters. Sub-modules in the MMC all employ full-bridge sub-modules, an auxiliary loop is added among bridge arms of the same DC bus side to build a new topology, energy equalization of three upper bridge arms and energy equalization of three lower bridge arms are maintained when the auxiliary circuit among the bridge arm works during the zero DC voltage fault ride-through process, all modular voltages are integratedly equalized by adjusting voltage deviation among the upper bridge arms and the lower bridge arms, a fault current is enabled to be eliminated during the zero DC voltage fault ride-through process of the MMC, reactive power support is continued to be provided for an AC system, and the energy equalization of the sub-modules is maintained particularly when the bridge arm parameters of the MMC are asymmetric. By the topology and the control method thereof, the voltage deviation caused by asymmetric bridge arm parameters can be jointly borne by the six bridge arms, the integral energy equalization is maintained, a short-circuit current is limited to a low level, and zero DC voltage fault ride-through is achieved.

The invention relates to the field of batteries, in particular to a current collector as well as a pole piece and a battery and an application thereof. The current collector comprises an insulation layer with a supporting function and a conductive layer with a conductive and current collection function, wherein a normal-temperature thin-film resistance RS of the conductive layer satisfies: RS is greater than or equal to 0.01 omega and less than or equal to 0.15 omega. By adopting the current collector, the short-circuit resistance when in short circuit under the abnormal condition of a batterycan be greatly increased, so that the short-circuit current is greatly reduced, the short-circuit heat can be greatly reduced, and the safety performance of the battery can be greatly improved; and in addition, due to the small heat yield, the heat produced at a point having the internal short circuit can be completely absorbed by the battery, the temperature increase of the battery is small, sothat the influence of the short-circuit damage for the battery can be limited in a range of the point, and only the point short circuit is formed without influencing the normal work of the battery ina short time.

The invention discloses a concentrated winding DC bias-type hybrid excitation permanent magnet motor, which comprises a stator (1), a rotor (2), a winding (3) and permanent magnets (4), wherein the rotor has a slotted convex pole structure. The concentrated winding DC bias-type hybrid excitation permanent magnet motor is characterized in that the stator (1) has a toothed boot structure, slots are arranged at two sides of the top ends of stator teeth or in the middle of top ends of an uneven number of stator teeth for accommodating the permanent magnets (4); and the winding (3) adopts a fractional-slot non-overlapped concentrated winding, and current in the winding comprises an AC component and a DC component. According to the hybrid excitation permanent magnet motor of the invention, as a special excitation winding is omitted, in a condition with the same copper consumption, the output torque is larger; reluctance in an excitation magnetic field generated by the DC component in an armature winding is little, and the magnetic field adjustment ability is strong; in short circuit fault, the short circuit current is small and the reliability is high; and besides, the motor structure is greatly simplified, the processing process is simple, and the cost is reduced.

The invention discloses a control method for reducing converter station short-circuit current of a two-end flexible direct-current power transmission system. The size of short-circuit current provided by the flexible DC converter station, the control mode, the operation condition and the influence of an inner and outer loop controller amplitude limiter are comprehensively considered. According to the control method, the rapid response characteristic of the flexible DC converter is utilized while it is ensured that the flexible DC converter station is not locked; by adjusting an outer ring controller reactive shaft current reference value of a receiving end converter station, and controlling alternating current output by the converter station when the alternating current system is short-circuited, short-circuit current provided for a fault point when a near-region short-circuit fault of the receiving end converter station occurs is reduced, the short-circuit current level of the alternating current system is further reduced, and important reference significance is achieved for application of the flexible direct current power transmission technology in engineering in China.

PROBLEM TO BE SOLVED: To provide a photovoltaic device with improved output characteristics. ŽSOLUTION: An i-type amorphous silicon film 21 and an n-type amorphous silicon film 22 are formed on a region except a predetermined width on an outer periphery of a principal plane of an n-type monocrystalline silicon substrate 11. A surface electrode 12 is formed to cover the films 21 and 22 on the principal plane of the n-type silicon substrate 11. An i-type amorphous silicon film 23 and a p-type amorphous silicon film 24 are formed entirely on the rear of the n-type substrate 11. A rear electrode 16 is formed on a region except a predetermined width on an outer periphery of the silicon film 24. The side of the surface electrode 12 serves as a main light receiving surface. Ž

The invention relates to a cylindrical lithium-manganese dioxide battery structure with high capability, wherein a ring of diaphragm (4) is wrapped on an outer surface of an anode electrical core (3), a lithium band (5) is arranged between the diaphragm (4) and a steel shell (1), a cover assembly (9) is located on the inner upper end of the steel shell (1), an anode core post (7) is located in the middle of the cover assembly (9), a metal connecting strip (10) is connected with the anode core post (7), the cover assembly (9) is provided with a liquid injection hole (11) and a sealing pin (8) for sealing the liquid injection hole (11), and an insulation sheet (6) for isolating an anode piece (3) from the lithium band (5) is arranged at the inner bottom of the steel shell (1). By adopting the cylindrical lithium-manganese dioxide battery structure, the capability of the battery is increased by 25.0%-36.4%, and the cost of materials is reduced. The invention further discloses a method for assembling the cylindrical lithium-manganese dioxide battery structure with high capability.

The invention provides a method for improving the photovoltaic conversion efficiency of a solar photovoltaic power generation panel, comprising: using an EVA adhesive film to bond a composite metamaterial film to the light-receiving surface of a solar photovoltaic power generation panel; the composite metamaterial film is prepared by the following method : Micron-sized SiO ₂ The microspheres are dispersed in the dispersant and ultrasonically oscillated to obtain SiO ₂ microsphere dispersion; make SiO ₂ The microsphere dispersion is evenly distributed on the polymethylpentene film, so that the SiO ₂ The microsphere dispersion is volatilized, and the distribution of SiO ₂ Polymethylpentene thin film of microspheres; using rolling machine to distribute SiO ₂ The polymethylpentene film of the microspheres was rolled to obtain the composite metamaterial film. The invention utilizes the principle of radiation cooling to significantly reduce the surface temperature of the solar photovoltaic power generation panel, thereby improving the photovoltaic conversion efficiency of the solar photovoltaic power generation panel, and also has the advantages of low energy consumption, high efficiency and simple structure.

The invention discloses a main and auxiliary cavity coupling type self-adaptive cyclone centrifugal degassing method. The main and auxiliary cavity coupling type self-adaptive cyclone centrifugal degassing method comprises the following steps: (1) a gas-liquid mixture enters a main cyclone cavity for hydrocyclone separation, and under the action of a centrifugal force, larger bubbles flow out froman overflow pipe at the top of the main cyclone, and the liquid containing a small amount of fine bubbles enters auxiliary cyclone cavities from tangential liquid inlets after passing through coupling channels; and (2) hydrocyclone separation is performed on the liquid containing the small amount of fine bubbles in the auxiliary cyclone cavities, and under the action of the centrifugal force, thefine bubbles flow out from the overflow pipes at the top of the auxiliary cyclones, and the degassed liquid flows out from the discharge ports of the auxiliary cyclones. The number of the coupling channels has a one-to-one correspondence with the number of the auxiliary cyclones, and the number is at least 2; the coupling channels and the auxiliary cyclones are evenly distributed along the outercircumference of the main cyclone; and the ratio of the centrifugal acceleration of the liquid in the auxiliary cyclones to the centrifugal acceleration of the liquid in the main cyclone is (5 to 100)to 1. The main and auxiliary cavity coupling type self-adaptive cyclone centrifugal degassing method and device disclosed by the invention have high separation efficiency and high degassing efficiency.

The present application relates to the field of batteries, and in particular, to a current collector and a pole piece thereof, and an electrochemical device. The current collector comprises an insulating layer and a conducting layer, wherein the conducting layer is positioned on at least one surface of the insulating layer, and the normal-temperature film resistance RS of the conducting layer meets the inequation as shown in the description; a plurality of holes penetrating the insulating layer and the conducting layer are formed in the current collector. The current collector can improve the short-circuit resistance of the battery in the case of short circuit under the abnormal condition, so that the short-circuit current is greatly reduced, the short-circuit heat production is greatly reduced, and the safety performance of the battery is improved; the plurality of holes arranged in the current collector can facilitate pass of the electrolyte, can reduce the polarization of the pole plate and the battery and can improve the electrochemical performance of the battery; and moreover, the holes arranged in the current collector can further reduce the weight of the current collector and can improve the weight energy density of the battery.

The invention provides a texturing technology and a diffusion technology of diamond wire solar cell pieces. The technical problems that the antireflection effect of an existing conventional chemical method is not obvious, the cost is increased by more than ten times after the whole set of a black silicon technology is matched and an existing diffusion technology is not matched with a texturing technology of diamond wires are solved. The texturing technology of the diamond wire solar cell pieces provided by the invention comprises the following steps: a, texturing; b, silicon wafer surface washing with ultrapure water; c, alkaline washing; d, silicon wafer surface washing with ultrapure water; e, mixed acid solution washing of hydrofluoric acid and hydrochloric acid; and f, ultrapure water washing and drying. The texturing technology has the advantage of low polycrystalline silicon reflectivity.

The invention discloses a low-frequency traction power supply system which is composed of traction substations and traction networks. Each traction substation comprises a traction transformer and a transducer, a primary-side three phase of each traction transformer is connected with a public utility grid, a secondary-side three phase of each traction transformer is connected with the corresponding transducer, traction sides output by the transducers is single-phase, and the traction networks are powered through single-phase traction buss. The power supply frequency f of the traction networks meets the following formula: fault removal time limit TS (ms) of the traction network=relay protection action time TR (ms)+half cycle lambda (ms), namely, f=500/(TS-TR), TS)TR and within 5Hz-16Hz, the traction networks of the traction substations can be connected to implement communicated power supply, and during interruption maintenance or traction-side fault of the traction substation, the transducers are switched off and related breakers are switched on. The low-frequency traction power supply system is widely suitable for power supply of metros with one line at one place, light-rail vehicles, tramcars and trolleybuses with two electric traction lines, and convenient to implement.

The invention discloses a SiC MOSFET gradual-change level driving circuit and method applied to a direct current solid state power controller. The method comprises the following steps: after passing a driving signal output by a driving circuit through an inverting circuit, outputting a first operational amplifier output signal; passing the first operational amplifier output signal through a trapezoidal wave generation circuit, carrying out integration on the first operational amplifier output signal and outputting a second operational amplifier output signal; carrying out in-phase proportion amplification on the driving signal via an in-phase proportion operational circuit and outputting a sixth connection signal; and carrying out addition calculation on the second operational amplifier output signal and the sixth connection signal, and outputting a gradual-change level circuit output signal, wherein the signal is the gradual-change level driving signal. According to the SiC MOSFET gradual-change level driving circuit and method disclosed by the invention, compared with the prior art, the voltage spike when a direct current SSPC inductive load is turned off can be effectively inhibited, the load compatibility of the direct current SSPC is improved, and the shortages of complex structure, complex engineering realization and the like are overcome.

The invention provides a pole piece and an application thereof, and a low temperature rise safety lithium ion battery containing the pole piece, the pole piece comprises a current collector, and at least two active coatings and at least one efficient conductive PTC film are fixedly arranged on each of two opposite surfaces of the current collector; the active coating and the efficient conductive PTC film are arranged at intervals from inside to outside from the surface of the current collector, and the outermost side is the active coating; the conductivity of the active coating on the outermost layer is smaller than that of the other active coatings, and/or the active substance of the active coating on the outermost layer adopts an active substance with high thermal stability. According tothe pole piece disclosed by the invention, the internal temperature distribution is more uniform, the temperature rise of conventional use or internal short circuit of the battery is reduced, and thermal runaway can be slowed down, so that the safety of the lithium ion battery is improved.

The invention relates to a three-phase current limiting device and a three-phase current limiting method. The device comprises three magnetic saturation reactors, three current transformers, three pairs of reverse parallel thyristors, a three-phase bridge type rectifying circuit and a control circuit, wherein the three magnetic saturation reactors are provided with reactance coils L1 and direct current coils L2 respectively; the three current transformers are provided with primary coils L3 and secondary coils L4 respectively; the three pairs of reverse parallel thyristors are connected in parallel with the secondary coil L4 of each current transformer; the reactance coils L1 of the magnetic saturation reactors are connected in series with the primary coils L3 of the current transformers; the remaining terminals of the reactance coils L1 are taken as a phase A input terminal, a phase B input terminal and a phase C input terminal of the device; the remaining terminals of the primary coils L3 of the current transformers are taken as a phase A output terminal, a phase B output terminal and a phase C output terminal of the device; the secondary coils L4 of the current transformers are taken as the input of the three-phase bridge type rectifying circuit; the output of the three-phase bridge type rectifying circuit is connected in series with a positive diode and then is connected inseries with the direct current coil L2 of each magnetic saturation reactor so as to form a direct current closed circuit; and the output of the control circuit controls the switch-on or switch-off ofthe three pairs of reverse parallel thyristors respectively.

The invention relates to a motor used in the mixed power vehicle, which comprises a rotor and a stator formed by permanent magnet and iron core. Wherein, the radial section of said rotor is in E-shape; the stator is inside the rotor annular groove whose part at one side of rotor annular groove has a motor case connecting the stator. The permanent magnet is circumferentially arranged at the inner surface of rotor, and with the increase of inner surface radius and in same motor size, since the torque of circumferential magnetic field sensing force is increased, the torque density of motor is improved significantly; the flywheel of motor is integrated with the rotor of electric motor; the rotary inertia of rotor is increased significantly; therefore, it can reduce the number of flywheels on the traditional power integration to integrate the motor and flywheels, with small volume, reduced weight of power integration, axial length, lower short-circuit current and lower instant brake torque.

The invention discloses a series-connection current limiting circuit of a miner lamp intrinsic safety power supply. The series-connection current limiting circuit of the miner lamp intrinsic safety power supply is characterized by comprising a DC/DC (Direct Current/ Direct Current) boosted circuit, a control circuit, a reference power supply, a current sampling circuit, a voltage sampling circuit and a three-stage series-connection power adjusting and protecting circuit, wherein the DC/DC boosted circuit is formed by an IC1 (Integrated Circuit), diodes, capacitors and a resistor and is used for supplying a control power supply; the control circuit is formed by an IC2 and resistors and used for setting and comparing the voltage and the current; the reference power supply is formed by an IC3, a resistor and a capacitor and is used for supplying the preset control voltage for a '+' input end of the IC2; the current sampling circuit is formed by a resistor R1 and a resistor R2, and the voltage sampling circuit is formed by a resistor R12 and a resistor R13, and the current sampling circuit and the voltage sampling circuit are respectively used for supplying the preset control voltage for a '-' input end of the IC2; and the three-stage series-connection power adjusting and protecting circuit is formed by an FET2 (Field Effect Transistor), an FET3 and an FET4. According to the series-connection current limiting circuit of the miner lamp intrinsic safety power supply, disclosed by the invention, the current limiting circuit is formed by applying power semiconductor devices and other electronic devices, and the situations that when in normal work, the inner resistances of the devices are kept to the lowest, and no influence on the working performance of loads is realized; and the inner resistances of the devices can be increased immediately when the loads are in over current or short circuit failure, the failure current can be immediately limited within the safety current, and thus the miner lamp power supply can be safely protected.