939 results about "Current voltage" patented technology

The invention provides an array substrate and a display device, and the array substrate comprises a substrate; the gate insulating layer is arranged on the substrate; the data line is arranged on the gate insulating layer; the first passivation layer is arranged on the gate insulation layer and covers the data line; the first shielding electrode is arranged on the first passivation layer, and the first shielding electrode is connected with the direct-current voltage signal output end; the second passivation layer is arranged on the first passivation layer and covers the first shielding electrode; the common electrode is arranged on the second passivation layer, and a part of the common electrode is overlapped with the data line and the first shielding electrode; the pixel electrode and the common electrode are arranged on the same layer or stacked, and the pixel electrode is insulated from the common electrode. The first shielding electrode is connected to the direct-current voltage signal, so that the data voltage signal on the data line does not affect the signal on the common electrode, coupling capacitance between the common electrode and the data line is avoided, and poor display of picture flicker is avoided.

The invention discloses an error correction method and device for non-intrusive voltage differential measurement, a medium and a product, and relates to the technical field of voltage measurement, and the method is applied to a scene in which a differential electric field sensor array is arranged in a set range with a measured conductor as the center. Comprising the following steps: constructing an initial correction model based on a sensor distance and a measured conductor voltage; under the actual working condition, the initial correction model is processed through a least square method, and a correction model is obtained; when non-intrusive voltage differential measurement is carried out, the current measured conductor voltage and the sensor distance are obtained, and a correction coefficient is determined by adopting the correction model; and completing error correction of non-intrusive voltage differential measurement based on the correction coefficient. According to the invention, the complexity of an inversion algorithm and the special requirement on the spatial position of the sensor can be reduced.

The invention discloses a distribution box operation state monitoring method and system, and relates to the field of distribution boxes, and the system comprises an acquisition module which is used for collecting current and voltage signals of each loop in a distribution box, surface temperature distribution of a box body and opening and closing state signals of a cabinet door, and converting the collected analog signals into a digital signal sequence; the extraction module is used for receiving the digital signal sequence and extracting a signal fluctuation feature, a temperature field distribution feature and a state signal change feature to generate a three-dimensional feature set; the system can obtain loop electrical parameters, box body temperature and cabinet door state in real time, accurately analyze operation characteristics to deduce state trend, quickly position defective loop components and influence range in case of abnormity, scientifically evaluate health level, timely give an early warning, synchronously disconnect power supply of associated equipment in case of severity, effectively reduce fault shutdown, and improve work efficiency. The power utilization safety and the maintenance efficiency are improved, and stable operation of the distribution box is guaranteed.

The invention relates to the technical field of power system control, in particular to a direct-current capacitor self-synchronizing grid-connected control strategy method, system, equipment and medium, a direct-current capacitor energy dynamic model is established based on an actual energy balance relation, a direct-current voltage signal is acquired in real time, and a synchronous compensation signal is calculated based on the acquired direct-current voltage signal; performing phase compensation and gain adjustment on the synchronous compensation signal through a correction link based on the calculated synchronous compensation signal, adjusting the internal frequency of the inverter based on the synchronous compensation signal after phase compensation and gain adjustment, controlling the DC voltage through the internal frequency of the inverter, and establishing a self-synchronization control model; and based on the self-synchronization control model, establishing an adaptive control algorithm, generating a damping coefficient and a virtual inertia coefficient through the adaptive control algorithm, and dynamically adjusting control parameters according to the damping coefficient and the virtual inertia coefficient.

The invention belongs to the field of new energy, and particularly discloses a direct-current bus voltage control method and system of a flywheel energy storage system. Comprising the following steps: if DC bus voltage is in a normal range, DC voltage forms a q-axis current reference signal after being adjusted by a PI controller, the q-axis current reference signal generates a q-axis voltage instruction signal after being adjusted by a current control loop PI, and a dq-axis voltage instruction value is generated through decoupling; if the current control loop slightly deviates from the normal range, parameters of a PI controller are adjusted, so that an integration link plays a leading role in control output, a virtual impedance link connected to the current control loop in parallel is adjusted, and a dq-axis voltage instruction value is generated; and if the voltage is seriously deviated from the normal range, a grid-side power signal is fed forward to a machine-side direct-current voltage control loop, virtual resistance in a virtual impedance link is adjusted, and a dq-axis voltage instruction value is generated. According to the invention, the control mode is automatically switched according to different conditions of the DC bus voltage by adopting a threshold-grading regulation and control strategy, and the adaptability to large disturbance is improved while the steady-state precision of the system is maintained.

The invention discloses a photovoltaic module early-stage fault early-warning method based on electric-thermal characteristic joint analysis, and belongs to the field of photovoltaic module early-stage fault early-warning, and the method comprises the steps: segmenting an irregular high-temperature or low-temperature region according to a temperature distribution image through employing a data segmentation algorithm, and extracting the boundary contour and area quantification characteristics of the abnormal region; performing joint feature vector construction by using the abnormal region boundary contour and area quantization feature and the current and voltage fluctuation amplitude in the electrical signal time sequence to obtain the comprehensive fault diagnosis vector; according to the preliminary fault classification label, extracting a temperature electrical corresponding association mode of a similar fault case from a historical fault diagnosis database, and obtaining an enhanced fault corresponding relation model; and generating a system risk assessment report by adopting the final fault diagnosis classification result, triggering a corresponding alarm mechanism, and judging the overall risk level of the renewable energy system.

The invention discloses a hydro-generator excitation loss fault diagnosis method and device, and belongs to the technical field of power system relay protection, and the method comprises the following steps: collecting the phase current and line voltage of a hydro-generator terminal; the collected current and voltage data are stored in a register in sequence, and after the register is full, the last data is deleted when a new group of data is stored; calculating an instantaneous power integral according to m groups of current and voltage data in the register and solving a discrete form of the instantaneous power integral; normalizing the obtained instantaneous power integral to obtain an initial field loss fault index; eliminating average fluctuation of the initial field loss fault index to obtain a final field loss fault index; and judging the field loss fault by combining whether the final field loss fault index is smaller than a threshold value or not and a low-voltage criterion, and locking the field loss fault criterion by using a direct-current component criterion and a negative-sequence voltage criterion to avoid an external fault. The method does not depend on the operation state of the generator too much, has high sensitivity, and reduces the maloperation risk.

An inertia cooperative control method of an integrated optical storage alternating current and direct current hybrid micro-grid comprises the steps that firstly, according to static and dynamic power capacities of energy storage units in direct current sub-grids and allowed direct current voltage deviation, sub-grid equivalent virtual resistance and virtual capacitance are calculated; secondly, RC + R type parallel virtual impedance parameters are distributed according to the power proportion of each energy storage unit, and multi-energy-storage cooperative response power disturbance according to the capacity is achieved; then, a phase angle is generated based on the mapping relation between direct-current side voltage and frequency, an alternating-current voltage amplitude instruction is determined in combination with reactive power droop control and feeder impedance voltage drop compensation, and a dq-axis voltage instruction is generated through virtual impedance compensation; normalized three-phase modulation waves are obtained through voltage-current double closed-loop control and dq / abc coordinate transformation, and six paths of PWM signals are generated to drive an interconnection converter after the normalized three-phase modulation waves are compared with triangular carrier waves. The method does not need to depend on external communication, has the capabilities of autonomous inertia support, voltage and frequency coordinated regulation and reasonable multi-source power distribution, and improves the stability and dynamic response performance of the system under island operation.

The invention discloses a boost charging control method and device. The method comprises the following steps: acquiring an insulation detection voltage of a charging pile and a maximum allowable voltage of the charging pile; if the charging pile insulation detection voltage and the charging pile maximum allowable voltage meet a preset judgment condition, the vehicle is controlled to enter a direct connection charging mode; in the direct connection charging mode, the current voltage of a vehicle battery pack is obtained; and if the current voltage of the battery pack meets the preset switching condition, the vehicle is controlled to be switched from a direct connection charging mode to a boost charging mode. According to the method, intelligent and accurate judgment of the output capacity of the charging pile is achieved, a dynamic optimization charging strategy is implemented in the single charging process, and the problems that the charging compatibility of a high-voltage platform vehicle type is poor, and the charging efficiency is limited by a traditional boosting scheme are solved.

The embodiment of the invention provides a flywheel energy storage system and an electrical control method and system thereof, and the electrical control method comprises the steps: collecting the operation state data of the flywheel energy storage system in real time, and carrying out the preprocessing of the operation state data; inputting the preprocessed operation state data into a parameter adaptive control algorithm, dynamically adjusting control parameters of the algorithm through fuzzy logic, and generating a control instruction for controlling the power converter; based on the control instruction and the real-time demand of a power grid, cooperatively controlling the output power and the direct-current voltage of the flywheel energy storage system, and when it is detected that the direct-current voltage deviates from a target range, automatically switching an electrical control mode to a voltage stabilization mode for stabilizing the direct-current voltage within the target range; and monitoring the operation state of the flywheel energy storage system in real time, and triggering a protection mechanism when at least one abnormity of overvoltage abnormity, overcurrent abnormity or mechanical fault abnormity is detected.

The invention is applicable to the technical field of voltage converters, and provides a control device and a control method of a direct-current voltage converter and electronic equipment, and the control device is configured to obtain the working state of the direct-current voltage converter, the permission state of a battery and the balance state of a low-voltage side capacitor bank; and when it is detected that the working state of the DC voltage converter is a standby state and the equalization state of the low-voltage side capacitor bank is an unbalanced state, the current flow direction in the charging and discharging module is controlled according to the permission state of the battery so as to perform equalization control on the voltage of each capacitor in the low-voltage side capacitor bank. According to the technical scheme, the low-voltage side capacitor voltage-sharing control is executed in advance when the direct-current voltage converter is in the standby stage, so that the system can directly enter the power control state after receiving the power request, the response time for reaching energy output under a power instruction is remarkably shortened, and quick starting and smooth switching are achieved.

The invention relates to the technical field of intelligent power distribution systems, and particularly discloses a voltage fault diagnosis method based on an intelligent voltage protector, and the method comprises the following steps: extracting influence characteristics based on power grid data when a voltage fault occurs, and building a voltage fault first recognition model according to the influence characteristics; determining similar faults of each voltage fault according to an output result after the experimental characteristics are input into the other types of voltage faults; establishing a second voltage fault identification model, wherein all the first voltage fault identification models and all the second voltage fault identification models are deployed at the local and the cloud respectively; extracting real-time influence characteristics and inputting the real-time influence characteristics into all the voltage fault first identification models to determine a target fault; and inputting the real-time influence characteristics into a voltage fault second identification model corresponding to the target fault, and judging the type of the current voltage fault. According to the invention, the accuracy of voltage fault type identification is improved.

The invention relates to the technical field, and discloses a fisheye test needle group for testing a circuit board, which comprises a test board, the test board comprises a heating pressing block, an insulating component and a base, a test sample is placed between the heating pressing block and the insulating component, the test sample comprises a sample body and fisheye needles extending from pins on the sample body, and the fisheye needles are arranged on the base. A plurality of groups of double-end probes and elastic sheets are mounted in the base and are in butt joint with fisheye needles, the fisheye needles, the double-end probes and the elastic sheets form a test needle group, when the test sample sinks, the fisheye needles are in butt joint with the double-end probes, the elastic sheets are in butt joint with the fisheye needles to form two pairs of contacts, and when the test sample sinks to guide a first pair of contacts to appear, the first pair of contacts are in butt joint with the fisheye needles. And the wedge-shaped surface in the sinking direction guides the elastic sheet to incline so as to form the second pair of contacts, so that the current and voltage required by Kelvin testing can be met, the two pairs of contacts and a plurality of testing points are integrated in a single structure, and the use requirement is met by the appearance of lateral force while vertical downward force exists.

The invention relates to a low-noise high-precision pressure measuring circuit which comprises a bridge type sensor, an alternating-current excitation signal source, a phase-sensitive detector, a low-pass filter, a reference signal source and a signal conditioning amplifier. The alternating current excitation signal source modulates a differential voltage signal generated by the bridge type sensor to a high-frequency alternating current excitation signal generated by the alternating current excitation signal source to obtain a high-frequency pressure signal; the high-frequency pressure signal is amplified by the signal conditioning amplifier to form a modulated signal; the phase-sensitive detector performs frequency mixing on the modulated signal and a reference signal generated by a reference signal source to obtain a frequency mixing signal; the frequency mixing signal is filtered by a low-pass filter to form a direct-current voltage signal for pressure measurement; the reference signal generated by the reference signal source and the high-frequency AC excitation signal generated by the AC excitation signal source have the same frequency. According to the circuit, signals are modulated to a high-frequency area with low noise energy to be processed by adopting alternating-current excitation and coherent detection technologies, the signals and noise are effectively separated, and extremely high measurement resolution and precision are achieved.

The invention discloses a hybrid cascade system commutation failure suppression method caused by sending end faults, and belongs to the technical field of high-voltage direct-current power transmission systems. The invention aims to provide the method for suppressing the commutation failure of the hybrid cascade system caused by the sending-end fault, which comprises the following steps of: monitoring the deviation between a direct current instruction value and an actual value in a system fault recovery period in real time, and dynamically adjusting a rectifier-side trigger angle instruction according to the deviation so as to control the direct current recovery rate and amplitude. According to the method, the dynamic recovery characteristic of the sending-end bus voltage and the constant direct-current voltage control effect of the inversion-side MMC are combined, and key influence factors of commutation failure are systematically analyzed; a commutation failure suppression strategy based on a rectification side additional trigger angle is provided. According to the method, the influence of the phase dynamic change of the alternating current bus voltage at the rectification side and the constant direct current voltage effect of the MMC at the inversion side on the commutation failure in the fault recovery process is fully considered, and reference is provided for safe and stable operation of the hybrid cascaded high-voltage direct current power transmission system.

The invention belongs to the technical field of power system recovery control, and discloses a power coordination control method of a hybrid energy storage auxiliary black-start system and a related device.According to the method, the total active power requirement of the black-start system is obtained and decomposed into three time scale components of fundamental waves, intermediate frequencies and high frequencies; the power is dynamically distributed to the lithium battery and the super capacitor, the distributed power is corrected based on the temperature, the operation time and the rated parameters, and finally the frequency change rate and the direct-current voltage change rate are calculated according to the actual power instruction and the system parameters so that the controller can output the control quantity. By adopting the method, the contradiction between the energy and the power density of a single power supply is overcome, the response speed and the continuous power supply capability are synergistically improved, the voltage frequency instability risk caused by load input is effectively inhibited, and the reliability and the high efficiency of black start are remarkably improved by perfecting hybrid energy storage coordination control.

The invention provides a subsynchronous oscillation monitoring system and method for a wind power generation system, and the system comprises a signal collection module which is used for obtaining an output current parameter and a power grid interface voltage parameter in a target wind power plant region, and generating a current and voltage monitoring value; the feature extraction module is used for extracting oscillation frequency parameters and oscillation feature parameter values based on the current and voltage monitoring values; the dynamic threshold module is used for acquiring a power grid load parameter and a wind speed parameter and generating a dynamic threshold parameter value through weighted calculation; the state judgment module is used for performing state logic judgment based on the oscillation frequency parameter and the dynamic threshold value to obtain an oscillation state judgment value; and the result output module is used for generating a monitoring alarm signal value based on the oscillation state judgment value. According to the method, dynamic environment response and accurate feature extraction can be combined, the monitoring sensitivity and reliability are enhanced, the misjudgment probability caused by external interference is reduced, the protection action accuracy is optimized, and stable operation of a power grid is guaranteed.

The invention relates to the technical field of high-voltage direct-current transmission, and particularly provides an LCC-full-bridge MMC series light HVDC converter station control method, which comprises the following steps: a rectification side of a power grid commutation converter adjusts direct-current power through an outer ring and an inner ring adopts linear trigger angle control to generate a trigger pulse; transformer tap adjustment is supplemented; on the basis of the established stable direct current system, an inversion side selects a minimum trigger angle as a control signal by coordinating three control rings of a turn-off angle, direct current voltage and direct current to form a control system; the full-bridge modularized multi-level converter is switched to a power grid following and network construction control mode according to power grid conditions; and when a direct current fault is detected, setting the trigger angle of the commutation converter of the power grid to be 90 degrees and switching the full-bridge modular multi-level converter to an STATCOM mode, thereby realizing direct current fault ride-through without locking the converter. According to the invention, direct-current fault rapid ride-through of the non-locking converter is realized.

The invention provides a battery charging control method, a battery management system and electronic equipment, and relates to the field of lithium batteries. Aiming at the problems that a lithium ion battery is easy to separate out lithium and the charging speed is limited when the lithium ion battery is charged in a low-temperature environment, when the temperature of the battery is lower than a low-temperature threshold value, high-voltage direct-current voltage pulses are applied to the battery, and Joule heat is generated by utilizing internal impedance of the battery, so that rapid self-heating of the battery is realized. In addition, in order to avoid lithium precipitation, it is ensured that the pulse voltage is higher than the open-circuit voltage of the battery and the pulse current is lower than a safety threshold value in the high-voltage direct-current voltage pulse. Therefore, the temperature of the battery can be quickly raised to the safe charging temperature window in the low-temperature environment, so that quick charging is realized while the risk of lithium precipitation is avoided, and the usability and the safety of the battery in the low-temperature environment are remarkably improved.

The invention discloses an error state prediction method and system for a direct-current voltage transformer, and relates to the technical field of electric power measurement on-line monitoring, and the method comprises the steps: obtaining the error data of a target direct-current voltage transformer; segmenting the error data by using a two-order sliding window; performing feature extraction on the time sequence matrix by using fast Fourier transform to obtain a time-varying feature and a time-invariant feature; fusing the time-varying features and the time-invariant features by using a multi-layer perceptron to obtain fused features; and inputting the time-varying features, the time-invariant features and the fusion features into an error prediction model constructed based on deep learning to obtain an error prediction state of the target DC voltage transformer. According to the method, through the synergistic effect of the adaptive window, feature extraction and fusion and sliding value correction, the adaptability, accuracy and stability of error prediction of the direct-current voltage transformer are improved, and more reliable technical support is provided for online monitoring and abnormal early warning of a power system.

The invention relates to a DC voltage secondary ripple suppression method. The method comprises the steps of obtaining direct-current bus voltage; subtracting the DC bus voltage from the reference voltage to obtain an error signal; suppressing a fluctuation component corresponding to a target frequency in the error signal through a resonance controller to obtain a first adjusting quantity; performing steady-state adjustment on a direct-current component in the error signal through the adjustment controller to obtain a second adjustment variable; performing phase rotation on the first adjusting quantity at the target frequency through a phase adjuster to obtain the first adjusting quantity after phase adjustment; superposing the first adjusting quantity and the second adjusting quantity after phase adjustment to obtain a target direct current signal; acting the target direct current signal on an inverter to control the inverter to output a target current; the target current is used for adjusting instantaneous active power exchange between the inverter and the alternating current power grid so as to adjust the direct current bus voltage, and the direct current bus voltage without secondary ripples is obtained.

The invention provides a self-adaptive active equalization method, device and system for a battery management system, and relates to the technical field of energy storage batteries, and the method comprises the steps: obtaining electrochemical impedance spectroscopy test data and charge and discharge curve segments corresponding to each battery cell in a battery pack; under the condition that the current voltage difference value of the battery cell is determined to be smaller than or equal to a preset voltage difference threshold value, inputting the electrochemical impedance spectroscopy test data and the charge and discharge curve segments into a prediction balance model to obtain a battery cell capacity attenuation rate prediction value output by the prediction balance model, and determining the capacity attenuation rate of the battery cell according to the battery cell capacity attenuation rate prediction value. A battery equalization priority ranking result is obtained; and executing corresponding energy transfer operation on the target battery cell according to the battery cell capacity fading rate predicted value and the battery equalization priority ranking result. According to the invention, accurate evaluation and efficient balance management of cell aging are realized.

The embodiment of the invention provides a method and a system for evaluating the health state of a converter of a wind turbine generator based on dynamic regularization. According to the method and the system, the health state evaluation dimension is improved from an original signal layer to a state feature layer. Specifically, firstly, through multi-domain mixed feature extraction, original multi-dimensional data streams (such as three-phase current and direct-current voltage) containing a coupling relation are intelligently condensed into a feature vector sequence capable of comprehensively representing the operation state of the system; then, a dynamic warping algorithm is applied to the high-dimensional feature space, and the health deviation degree is quantified by measuring the warping distance between the real-time state feature sequence and the health benchmark. According to the normal form which is firstly extracted and then structured, the internal coupling relation among the physical quantities is used as core information to be fused into the evaluation process, so that the problem that multi-dimensional data cannot be effectively utilized in a traditional method is fundamentally solved, and the capturing capacity of early weak faults is remarkably improved.

A modular multi-level direct-current transformer topology applicable to a multi-voltage-class direct-current power grid, and a control method therefor. The topology comprises a bridge arm inductor, an upper bridge arm, a lower bridge arm and a filter inductor, wherein one end of the bridge arm inductor is connected to a positive electrode of a high-voltage side, and the other end thereof is connected to one end of the upper bridge arm; the other end of the upper bridge arm is connected to one end of the lower bridge arm and one end of the filter inductor; the other end of the lower bridge arm is separately connected to a negative electrode of the high-voltage side and a negative electrode of a low-voltage side; the other end of the filter inductor is connected to a positive electrode of the low-voltage side; and the upper bridge arm and the lower bridge arm each comprise a sub-module string, the sub-module string comprising several sub-modules, which are sequentially connected in series, and the upper bridge arm and the lower bridge arm regulate respective bridge arm voltages by means of controlling the number of inserted sub-modules, so as to realize direct-current voltage conversion between different voltage classes. In the present application, the use of upper and lower sets of chained sub-modules reduces the use of complex assemblies, thereby reducing the cost and the control difficulty, and also improving the safety, reliability and efficiency of a system.

The embodiment of the invention discloses a battery cell detection method and device and a storage medium, and the method comprises the steps: controlling a multi-parallel battery pack system to complete one time of current work when it is judged that the charge state of each battery module meets a corresponding change judgment interval; after the multi-parallel battery pack system completes the current work once, judging whether the duration of the current voltage value of the target battery module meets a set duration condition or not; if the set duration condition is met, adding 1 to the triggering times of the target battery module; and when it is judged that the triggering times of the target battery module are larger than or equal to a triggering time threshold value, reporting that the battery module where the target battery module is located has a battery cell disengagement fault. According to the embodiment of the invention, the technical problems of high thermal runaway risk and high power loss risk caused by the fact that a battery pack formed by connecting a plurality of battery cells in parallel in the prior art cannot identify the disconnection fault of a single battery cell are solved.

The invention discloses an insulation resistance measurement method, a measurement module and an anti-reverse power transmission isolation device, and relates to the field of operation and maintenance of distribution lines, and the key points of the technical scheme are as follows: a control voltage signal is generated according to the voltage demand of the insulation resistance of a test line sent by a user, and a PWM square wave signal with a duty ratio is generated according to the control voltage signal; performing high-frequency voltage transformation and voltage doubling rectification on the PWM square wave signal to obtain a direct-current voltage; calculating a current average value of the measurement loop when each resistance measurement gear is switched; presetting a current coefficient of each resistance measurement gear and weight coefficients of two adjacent resistance measurement gears; and when the current average value is greater than or equal to the product of the current coefficient and the weight coefficient, calculating the insulation resistance value of the measured circuit according to the current average value, the direct-current voltage and the resistance value corresponding to the resistance measurement gear.

The application relates to an adaptive control system of a bionic arm modular joint, which is installed between a bionic arm and a human shoulder, and the system comprises a collection module, a processing module, an adaptive controller module and a torque calculator module; the collection module obtains an initial control voltage group; after being processed by the processing module, a load torque, an input current and an input rotating speed are obtained; the load torque, the input current, the input rotating speed and a preset rated rotating speed are input into the adaptive controller module to obtain a first voltage group; after being processed by the processing module, a compensation control voltage of the modular joint is obtained; the compensation control voltage is input into the processing module to obtain an encoding value; and the processing module drives the modular joint according to the encoding value. Compared with the prior art, the adaptive control requirement is realized by obtaining an easily controlled current voltage value, and the application has the advantages of strong real-time performance, accurate control and the like.

The invention discloses a DC voltage control method and system for an MMC converter, and belongs to the technical field of power electronic control. The method comprises the steps of performing energy flow trend evaluation according to a historical load and a new energy output data sequence in a historical time zone when an MMC converter is connected to a power grid, and obtaining a predicted power surplus and deficiency coefficient; dynamically correcting a preset direct-current voltage reference value according to the predicted power clearance coefficient to obtain an adaptive direct-current voltage instruction; and sending the final modulation wave to a bottom layer controller of the MMC converter, and executing direct current voltage stability control in a preset time zone. According to the method and the device, the technical problems of slow DC voltage dynamic response, large overshoot and difficulty in considering sub-module voltage sharing when the MMC deals with complex power grid disturbance in the prior art are solved, and the technical effects of remarkably improving the anti-disturbance capability and the dynamic response speed of the MMC system on the premise of ensuring the DC voltage steady-state precision are achieved.

The utility model discloses a sine pulse width modulation circuit and a switching power supply, and the circuit comprises a sine wave generation circuit which comprises a voltage division circuit, an RC oscillation circuit, a differential comparison amplification circuit, and a gating circuit; the voltage division circuit is used for carrying out voltage division processing on power supply voltage input by the input end of the sine pulse width modulation circuit and then outputting a direct-current voltage signal; the RC oscillating circuit is used for converting the direct-current voltage signal into an alternating-current oscillating signal and outputting the alternating-current oscillating signal; the differential comparison amplification circuit is used for comparing and amplifying the AC oscillation signal and the DC voltage signal and then outputting an AC voltage signal; the gating circuit is used for gating the AC voltage signal and then outputting a sine wave signal; the negative half-cycle rectifying circuit is used for overturning and rectifying a negative half-cycle signal in the sine wave signal and then outputting the negative half-cycle signal; and the positive half-cycle rectifying circuit is used for overturning and rectifying a positive half-cycle signal in the sine wave signal and then outputting the positive half-cycle signal. According to the utility model, the cost, volume and weight of the product can be reduced.

The invention discloses an operation parameter optimization method and system for improving the overload capacity of a power electronic converter, and belongs to the technical field of power electronics. The method comprises the following steps: constructing an output current model considering current ripples in a switching period, and obtaining an accurate current waveform expression; calculating conduction loss and switching loss of each power device in each switching period based on the model; under a set temperature rise or loss constraint condition, parameters such as direct-current voltage and switching frequency are optimized through an optimization algorithm, and the optimized parameters are applied to converter operation. The method solves the problem that loss estimation is inaccurate due to the fact that a traditional simplified model ignores current ripples, through precise modeling, refined loss calculation and scientific parameter optimization, the thermal stress of a device is remarkably reduced, the overload capacity of the converter is improved, the method is suitable for various topologies such as a two-level converter, a three-level converter and a direct-current converter, and the method has wide application prospects. The method can be widely applied to the fields of new energy and rail transit.