134 results about "V curve" patented technology

This invention provides a solar simulator measurement method capable of high-accuracy measurements with fast-response photovoltaic devices as well as with slow-response photovoltaic devices, and a solar simulator for implementing the method. A flash having a pulse wave form with a flattened peak is generated from a xenon lamp 1. The flash is sensed by an irradiance detector 3, its irradiance measured, and the irradiance of the light source is adjusted to fall within a prescribed narrow range based on the detected irradiance value. Then, the flash with irradiance within the prescribed range irradiates photovoltaic devices 4 under measurement, and the current and the voltage output by the photovoltaic devices 4 are measured at multiple points while a load of the photovoltaic devices 4 is controlled. This process is repeated with multiple flashes to obtain an I-V curve for the photovoltaic devices.

A threshold device including a plurality of adjacent tunnel barrier layers that are in contact with one another and are made from a plurality of different dielectric materials is disclosed. A memory plug having first and second terminals includes, electrically in series with the first and second terminals, the threshold device and a memory element that stores data as a plurality of conductivity profiles. The threshold device is operative to impart a characteristic I-V curve that defines current flow through the memory element as a function of applied voltage across the terminals during data operations. The threshold device substantially reduces or eliminates current flow through half-selected or un-selected memory plugs and allows a sufficient magnitude of current to flow through memory plugs that are selected for read and write operations. The threshold device reduces or eliminates data disturb in half-selected memory plugs and increases S / N ratio during read operations.

A system and methods for measuring the performance of individual strings of photovoltaic (PV) modules in a PV array, including a string combiner box with integrated capability for measurement of string current versus voltage (I-V) characteristics. The system may include calibrated solar insolation reference devices; environmental meters; and / or at least one system computer. The string combiner box allows: high precision string performance measurement during normal power generating operation; isolation of individual strings or groups of strings; and the performance of high-precision full I-V sweeps on individual strings. Methods are provided to analyze measured I-V curves to compensate for the effects of temperature and other variables thereby increasing PV module performance measurement accuracy. Methods are further provided to incorporate data from insolation reference devices and / or environmental meters to extract meaningful parameters from collected data regarding PV module efficiency and degradation, and track string-level performance and degradation over extended periods of time.

A method for eliminating the radiation-induced off-state current in the P-channel ultrathin silicon-on-sapphire transistor, by providing a retrograde dopant concentration profile that has the effect of moving the Fermi level at the back of the device away from that part of the bandgap where the interface states are located. When the Fermi level does not swing through this area in any region of operation of the device, subthreshold stretchout of the I-V curves does not occur.

HF-originated radicals generated in a plasma-forming chamber are fed to a treatment chamber via feed holes, while HF gas molecules as the treatment gas are supplied to the treatment chamber from near the radical feed holes to suppress the excitation energy, thereby increasing the selectivity to Si to remove a native oxide film. Even with the dry-treatment, the surface treatment provides good surface flatness equivalent to that obtained by the wet-cleaning which requires high-temperature treatment, and further attains growth of Si single crystal film on the substrate after the surface treatment. The surface of formed Si single crystal film has small quantity of impurities of oxygen, carbon, and the like. After sputtering Hf and the like onto the surface of the grown Si single crystal film, oxidation and nitrification are applied thereto to form a dielectric insulation film such as HfO thereon, thus forming a metal electrode film. All through the above steps, the substrate is not exposed to atmospheric air, thereby suppressing the adsorption of impurities onto the interface, and thus obtaining a C-V curve with small hysteresis. As a result, good device characteristics are obtained in MOS-FET.

This invention provides a solar simulator measurement method capable of high-accuracy measurements with fast-response photovoltaic devices as well as with slow-response photovoltaic devices, and a solar simulator for implementing the method. A flash having a pulse waveform with a flattened peak is generated from a xenon lamp 1. The flash is sensed by an irradiance detector 3, its irradiance measured, and the irradiance of the light source is adjusted to fall within a prescribed narrow range based on the detected irradiance value. Then, the flash with irradiance within the prescribed range irradiates photovoltaic devices 4 under measurement, and the current and the voltage output by the photovoltaic devices 4 are measured at multiple points while a load of the photovoltaic devices 4 is controlled. This process is repeated with multiple flashes to obtain an I-V curve for the photovoltaic devices.

The invention provides a sudden capacity failure fault identifying and predetermining method for a lithium iron phosphate power battery. The charging capacity Q and terminal voltage V of the battery in a current-constant charging process are recorded in a preset sampling period to obtain a Q-V curve of the charging process; value differential is carried out on the Q-V curve of the charging processto obtain a dQ / dV-SOC curve; characteristics of the dQ / dV-SOC curve are compared with those of a standard dQ / dV-SOC curve of the battery, and change of characteristic peaks near SOC=50% and SOC=80% in the dQ / dV-SOC curve is analyzed; and LLI information is obtained. The method can be used to reflect internal state of the condition in a lossless way, whether there is a sudden capacity failure fault in the battery and reasons for the fault can be determined visually, 400 times of circulation can be predetermined and identified before sudden capacity failure, and a lithium ion power storage battery of a new energy vehicle is avoided from the risk of sudden capacity failure during operation and utilization after decommissioning.

The invention relates to the technical field of battery capacity calculation, and discloses an estimation method for SOC of a lithium battery. The method comprises the following steps of firstly obtaining a charging / discharging SOC-V curve under the conditions of different temperatures, current power and circulation times according to historical data of a lithium battery to be estimated through data fitting; calculating the point with the maximum curvature in each point at the front end of the curve as a front turning point and the point with the maximum curvature in each point at the back endas the back turning point; then, performing data fitting on the front turning point and the back turning point under the conditions of different temperatures, current power and circulation times; performing calculation to obtain a turning point modification coefficient equation under the corresponding condition; then, calculating the front turning point and the back turning point under the conditions of the reference temperature, the reference current power and the first circulation time and the corresponding SOC; performing conversion to obtain the front turning point and the back turning point under the corresponding work conditions by using the turning point modification coefficient equation; finally recording the turning point voltage reaching moment of the lithium battery to be estimated under the located work condition; and replacing the moment by the corresponding SOC value to obtain the SOC.

This invention provides a solar simulator measurement method capable of high-accuracy measurements with fast-response photovoltaic devices as well as with slow-response photovoltaic devices, and a solar simulator for implementing the method. A flash having a pulse waveform with a flattened peak is generated from a xenon lamp. The flash is sensed by an irradiance detector, its irradiance measured, and the irradiance of the light source is adjusted to fall within a prescribed narrow range based on the detected irradiance value. Then, the flash with irradiance within the prescribed range irradiates photovoltaic devices under measurement, and the current and the voltage output by the photovoltaic devices are measured at multiple points while a load of the photovoltaic devices is controlled. This process is repeated with multiple flashes to obtain an I-V curve for the photovoltaic devices.

The invention discloses a photovoltaic module output characteristic judgment method which is mainly characterized in that a single battery serves as a basic unit, output characteristics of a blocked battery and a battery string with the blocked battery are firstly analyzed according to current flowing through a photovoltaic module, and the conducting state of a bypass diode is further judged based on theoretical analysis for volt-ampere characteristics of the bypass diode, so that multimodal characteristics of the photovoltaic module blocked by shadow are calculated. By the method, the conducting point of the bypass diode can be accurately judged, so that peak points of an I-V curve of the module are accurately reflected, and a foundation is laid for simple and accurate simulation of the performance of the module under the condition of mismatch.

The invention relates to an IV characteristic and deep residual network-based photovoltaic array fault diagnosis method. The IV characteristic and deep residual network-based photovoltaic array faultdiagnosis method comprises the steps of firstly, building a model array by Simulink, and acquiring electrical data and environmental data under various working conditions; secondly, removing abnormaldata in original simulation data, acquiring an original I-V curve, performing sampling, and splicing one-dimensional characteristic to two-dimensional characteristic used as total characteristic of afault; thirdly, dividing sample data to a training set, a verification set and a test set, designing a network structure of residual convolution neural network with dimensional conversion and a training parameter of a training algorithm Adam, and performing sample training to obtain a DT-ResNet fault diagnosis training model; and finally, detecting and classifying photovoltaic power generation arrays under the test set in a to-be-tested working condition by the DT-ResNet fault diagnosis training model, and diagnosing a fault type. The method has the advantages of high accuracy, rapid convergence, high robustness, wide generalization capability and the like, and fault detection and classification accuracy of the photovoltaic power generation array can be effectively improved.

The invention provides a moonlet sun array life forecast method based on I-V curve and energy balance. Aiming at the problems that the existing moonlet sun array life forecast method has few damage regularity space environment influencing factors, is limited in life forecast of unit cells to the large extent, cannot forecast the whole life of a sun array, and the like, the moonlet sun array life forecast method is based on space environment simulation tests, and a sun array integral life forecast module is provided taking important space environment factor influence including sun and earth distance factors, track earth shadow time, included angles of sun rays and sun array normals, temperature and sun radiation into account, further the problem of generality of life forecast taking the sun array important life influence factors into account and sun array integral life forecasting suitable for different bathes and different types is solved. The I-V curve is a current and voltage curve of a solar unit cell. The moonlet sun array life forecast method is based on tests, and has good model generality and strong engineering practical applicability.

The invention discloses a performance degradation monitoring system for a photovoltaic cell. The system comprises a testing light source module, an I-V curve detection module, a channel switching module, a load loading module, a communication control unit and a processing terminal, wherein the I-V curve detection module detects a volt-ampere characteristic curve outwards output by the photovoltaic cell device; the processing terminal calculates the optimal load value of the maximum power point of the photovoltaic cell device according to the volt-ampere characteristic curve detected by the I-V curve detection module; the load loading module loads a load resistor of the corresponding resistance on the photovoltaic cell device according to the optimal load value. The load obtained by calculation is loaded on the detected photovoltaic cell device through the load loading module, and therefore the photovoltaic cell device does work outwards all the time in the testing process, the process better accords with actual situations of the photovoltaic cell device in the actual working process, and the degradation of the device in the actual working state is simulated more objectively and accurately.

Method and apparatus for constructing diagrams representing the relationship between variable quantities. According to the method, at least one first measurement point representing the relationship between the variable quantities is provided for initially constructing the diagram. Thereafter, at least one location is selected at which the relationship between the variable quantities is to be measured, the at least one location being selected as a function of the at least one measurement point. The relationship between the variable quantities is then measured at the at least one location to provide at least one additional measurement point for further constructing the diagram. The invention permits diagrams, such as V Curve diagrams, Bathtub Curve diagrams and Eye Diagrams, to be constructed in less time and using fewer measurement points than conventional diagram construction procedures.

The invention relates to an overheat protection device and method of an inverter. The overheat protection method comprises the following steps of: detecting real-time temperature of a power device of the inverter in the operation process; judging whether the real-time temperature is greater than a first preset temperature; and if so, boosting the maximum power tracking output voltage to the right side of a maximum power point of a P-V curve, carrying out amplitude-limiting on active current giving and reducing the active current giving, wherein the output power of the inverter is reduced by reduction of the active current giving so that the temperature of the power device is reduced. The overheat protection device and method disclosed by the invention have the advantages of capabilities of carrying out rapid control on the temperature in real time, avoiding larger fluctuation of the output power of the inverter, controlling the output power of the inverter to be zero without poweroff and effectively prolonging the grid-connected generation time of the inverter.

The invention relates to a non-destructive detection method of an underground unfavorable geological body based on microtremor dispersion curves and H / V curves and an application thereof. The detection method comprises the steps of (1) collecting surface micro-vibration signals of a plurality of measuring points, (2) calculating Rayleigh surface wave phase velocity dispersion curves in a micro-motion array, an H / V curve of each measuring point of a detector in the array and an array geometric mean H / V curve, (3) allowing each curve to form a contour map, and (4) inferring an anomalous geological body according to anomaly characteristics in the contour maps. The method is used for detecting longitudinal and lateral heterogeneous geological bodies within a depth range of 100 meters in a shallow ground surface in urban engineering construction. The probability of revealing lone stones and karst in the detection of the unfavorable geological bodies in subway shield construction is improved, and a safety area of shield tunneling construction is rationally divided. The detection method and the application have the advantages of convenient on-site collection, high detection precision, strong resolution, the shortening of a survey period, the reduction of engineering cost and the reduction of exploration risks.

A method for eliminating the radiation-induced off-state current in the P-channel ultrathin silicon-on-sapphire transistor, by providing a retrograde dopant concentration profile that has the effect of moving the Fermi level at the back of the device away from that part of the bandgap where the interface states are located. When the Fermi level does not swing through this area in any region of operation of the device, subthreshold stretchout of the I-V curves does not occur.

The invention discloses a realizing circuit of a memory container. The realizing circuit comprises a first operational amplifier, a second operational amplifier, a first capacitor, a second capacitor, a third capacitor, a resistor, a feedback resistor, a current feedback operational amplifier and a first multiplying unit, wherein the realizing circuit of the memory container is formed by the mutual connection of the above parts, a q-v curve obtained by measuring the circuit to meet an obvious memory effect shown by a magnetic control type memory container, and a status variable relation curve has hysteresis, therefore the realizing circuit is equivalent to the magnetic control type memory container; furthermore, the realizing circuit is simple in structure, and parameters can adjusted conveniently.

A testing method utilizes light feedback and automatic control technique to modify camera used flash light or similar ones to be impulse xenon lamp with constant light strength in addition to conventional program-controlled electron load, testing circuit and computer. The light impulse with several milliseconds of constant light strength can be obtained at each flash of the light source and I-V curve data collection of solar energy battery can be finished by computer-controlled testing circuit within the period of single flash and to finalize test of solar battery electric parameter in several seconds. The method also can be used to test solar battery component as well as can be utilized to manufacture the testing device for both of one-body solar battery and solar battery component.

A general method is given for screening laser diodes for electrostatic discharge, (ESD), damage. The laser diode may be selectively isolated from the laser driver so that a current-voltage (I-V), curve can be taken and then compared to curves taken previously on the same laser diode to ascertain the possibility of ESD damage. Presumably the initial I-V curve will be representative of the characteristics of that particular laser in the undamaged state. Such an initial curve may be supplied by the manufacturer and may be a curve specific to a particular laser diode. Comparison with a standard curve is not sufficient to determine ESD damage in the early stages of failure. Some embodiments focus on isolating the laser diode from the laser driver, storing the information locally in the transceiver, and providing some analysis resulting in flagging laser diodes showing changes that are indicative of ESD damage.

The invention provides a self-heating effect evaluation method and self-heating effect evaluation system of an LDMOS transistor. In the self-heating effect evaluation system, the LDMOS transistor is adjacent to a temperature sensing device. According to a temperature measuring unit, the temperature of the temperature sensing device can be obtained. The self-heating effect evaluation unit takes the temperature of the temperature sensing device obtained by the temperature measuring unit as the temperature of the LDMOS transistor and can obtain the relation between the leakage current value of the LDMOS transistor and signal voltage and temperature according to the temperature of the LDMOS transistor and the source and leakage current value and signal voltage of the LDMOS transistor. Thus the influence of the self-heating effect on the I-V curve of the LDMOS transistor can be simulated, in the future circuit design, according to the obtained relation between the leakage current value of the LDMOS transistor and the signal voltage and temperature, the self-heating effect can be used as the reference effect which influences the source and drain current values of the LDMOS transistor, and thus the design performance of the LDMOS transistor is more close to actual performance.

The invention discloses a fault detection system and method suitable for a photovoltaic array, and relates to the technical field of photovoltaic fault detection. The method comprises the following steps: calculating the maximum output power of a photovoltaic array under the simulation condition, and simultaneously recording the current value and the voltage value when the maximum output power isobtained; measuring the I-V characteristic, and after measurement of many times, obtaining a short-circuit current value, open-circuit voltage and a P-V curve peak value number of the photovoltaic array from an I-V curve; comparing the theoretical output power in simulation with the actual output power, and judging the mode of the photovoltaic array by an area where the ratio of the theoretical output power and the actual output power is; If the photovoltaic array is judged to be faulty, further judging the fault type, and using a threshold value method to isolate the faults with different attributes; and distinguishing two sets of faults with the same attribute by an extendable network model. The method can not only discover the fault on line when the photovoltaic array fails, but can also quickly locate the fault type.

The invention discloses a metal-semiconductor contact nonlinear transmission line model and parameter fitting method and relates to the semiconductor device structure performance detection and representation field. The metal-semiconductor contact nonlinear transmission line model and parameter fitting method comprises 1, establishing a nonlinear transmission line model; 2, measuring an I-V curve of parallel double rectangular electrodes on semiconductor thin film materials; 3, obtaining an R-V curve through a relational expression that R is equal to dV / dI; 4, calculating a theoretical R-V curve of a testing structure through the nonlinear transmission line model; 5, fitting metal-semiconductor contact physical parameters through a simulated annealing inheritance algorithm. The metal-semiconductor contact nonlinear transmission line model and parameter fitting method has the advantages of establishing the nonlinear transmission line model and a corresponding numerical algorithm, quantitatively extracting the metal-semiconductor contact relevant physical parameters and providing a new method for precise representation and analysis of nonlinear metal-conductor contact.

The invention discloses a photovoltaic array I-V characteristic testing device and a testing method thereof. The testing device is used for measuring I-V characteristics of a photovoltaic array to be tested and comprises a control circuit, a driving circuit and a display circuit. The driving circuit is at least one field-effect power tube, and the control circuit is used for changing output current of the photovoltaic array to be tested by controlling driving voltage VGS of the field-effect power tubes so as to simulate variable load of the photovoltaic array to be tested and simultaneously used for sampling voltage values and current values of the photovoltaic array to be tested under different loads. The display circuit is used for displaying voltage values and current values of the photovoltaic array to be tested under different loads and drawing an I-V curve of the photovoltaic array to be tested. The photovoltaic array I-V characteristics testing device has the advantages of small size, light weight, low cost and high reliability by adopting an MOSFET (metal-oxide semiconductor field effect transistor) as a power switch of the control circuit. The invention further discloses the testing method of the testing device.

The invention relates to a photovoltaic charger control device which comprises a photovoltaic voltage sampling unit, an output current sampling unit, an output voltage sampling unit, an MPPT unit, a first voltage controller, a voltage stabilizing control given unit, a second voltage controller, an amplitude limiting control unit, a current controller and a PWM generator. A photovoltaic charger control method comprises the steps that an MPPT control ring, a voltage stabilizing control ring, two voltage inner rings and a current control outer ring are adopted, the MPPT control ring output minimum value and the voltage stabilizing control ring output minimum value are selected as the given Iref of the current control outer ring, the output current value Ibuck of a photovoltaic charger is used as the feedback of the current control outer ring, the current control outer ring outputs the driving duty ratio to the PWM generator, and the PWM generator generates PWM driving signals to drive a switch tube of a main circuit of the photovoltaic charger to work. According to the photovoltaic charger control device and method, it is ensured that the photovoltaic voltage is always on the right side of a polar plate P-V curve, no output current jumping occurs, and it is ensured that photovoltaic energy is used more efficiently.

The invention discloses a system and a method for simulating the output of a solar cell array based on a programmable power supply. The system comprises a control computer, the programmable power supply and a resistor R, wherein the computer is used for setting a maximum voltage VMAX and a maximum current IMAX of the programmable power supply according to an open-circuit voltage VOC, a short-circuit current ISC, a maximum power point voltage VMP and a maximum point current IMP of the solar cell array; the programmable power supply is used for supplying power to a load under the limit condition of the maximum voltage VMAX and the maximum current IMAX; and the resistor R is connected between the programmable power supply and the load and is used for simulating the internal resistance of the solar cell array. By utilizing the system for simulating the output of the solar cell array based on the programmable power supply, a power supply working point can be adjusted according the load, thereby simulating the I-V curve output of the cell array; and the system is simple in structure and low in realization cost.

The method brings forward a method for precisely simulating performance of a photovoltaic battery piece. According to a solar battery duodiode model, the method comprises following steps: listing an equivalent equation of the output feature of the model; utilizing a Taylor's formula to descend power to solve such that relations between working current piece and working voltage of the battery is changed to be a linear function; and drawing an I-V curve corresponding to the battery piece based on the electricity performance parameter of the battery piece under the standard condition set by a manufacturer and obtaining electricity performance conditions under different working conditions by controlling light intensity and temperature of the battery piece. The method for precisely simulating performance of the photovoltaic battery piece has following beneficial effects: compared with a single-diode four-parameter method, the method has greater accuracy and especially has greater accuracy than a single-diode model under the condition of low irradiance; and the greatest working point basically coincides with parameters provided by the manufacturer within the range of degree of deviation of 2%.

The invention relates to a novel multi-channel solar cell module test system and a double intelligent scan method. The test system includes a plurality of solar cell module test units, an alternating current power supply, an industrial control computer and communication lines, wherein the alternating current power supply is connected with the plurality of solar cell module test units and the industrial control computer, and the industrial control computer is connected with the plurality of solar cell module test units through the communication lines. The novel multi-channel solar cell module test system in the invention uses a constant current source electronic load in a solar energy data collector to apply a double intelligent scan method under actual sunlight and atmospheric conditions, so as to realize synchronous and real-time measurement of module parameters of a plurality of solar cell modules, the industrial control computer obtains, processes and stores measured data of the module parameters through the solar cell module test units, outputs an I-V curve, temperature data and a P-T curve of a maximum power point within 24 hours of each solar cell module. The novel multi-channel solar cell module test system in the invention has the advantages of short test time, real test conditions and environment, low cost and the like, and is suitable for large-scale market promotion.

The invention provides a portable solar cell J-V curve measuring instrument. The portable solar cell J-V curve measuring instrument is structurally characterized in that the measuring instrument is composed of a voltage gauge, a current gauge, a variable resistor and a wire and operationally characterized in that a resistance value of an externally connected circuit of a solar cell is changed in order to change the output voltage and the output current of the solar cell. The solar cell J-V curve measuring instrument can provide a stable and reliable analyzing test for the solar cell. The basic measuring functions comprise complete I-V curve measuring, complete J-V curve measuring, complete P-V measuring, short circuit current measuring, open circuit voltages measuring, short circuit current density measuring, peak value power measuring, peak value power current measuring, peak value power voltage measuring, energy converting efficiency measuring, fill factor FF measuring and the like. The portable solar cell J-V curve measuring instrument is low in and assembly and manufacture cost and reliable in performance.