3117 results about "Voltage drop" patented technology

The invention discloses an automatic anchor point searching and processing method for grid-connected test data of a photovoltaic inverter, and belongs to the technical field of automatic test of a power system. According to the method, a three-phase voltage and current signal output by a power grid simulator and an inverter power instruction signal are aligned through a high-precision time synchronization device; wavelet transform multi-scale noise reduction and moving average filtering combined preprocessing is adopted to improve the signal-to-noise ratio; identifying a voltage zero crossing point candidate set, a drop starting point candidate set and a recovery termination point candidate set based on a self-adaptive dynamic threshold value; transient energy characteristic verification is introduced for a voltage drop starting point; effective anchor points are confirmed through time window association of power instruction step changes. According to the method, the problems of low efficiency of manual key event point identification, misjudgment caused by noise interference, grid event and inverter response time sequence correlation missing and the like are solved, and the automation degree of test data analysis, anchor point positioning precision and control response time sequence analysis reliability are remarkably improved.

The invention discloses an IGBT junction temperature real-time decoupling modeling method and system based on dynamic electric heating compensation, and relates to the technical field of state monitoring of power electronic devices. At present, junction temperature estimation is not accurate due to IGBT on-state voltage drop measurement distortion and chip internal thermal gradient in a high-voltage environment. The method comprises the following steps: in an offline stage, constructing an ideal electrothermal characteristic database of an IGBT, a dynamic temperature gradient compensation database in a chip and Foster thermal network model parameters; in the on-line stage, synchronous sampling and preprocessing are carried out on IGBT module operation parameters; combining online real-time parameters with an offline database by using an adaptive Kalman filter, and iteratively and cooperatively estimating the real-time junction temperature and loss of the IGBT; and finally, outputting and applying the estimated accurate junction temperature and loss data. According to the technical scheme, the hot spot effect in the chip is accurately decoupled, the junction temperature estimation precision and the robustness of online monitoring are improved, and core data support is provided for fine thermal management and early fault early warning of the flexible direct current converter valve.

The invention discloses a single storage battery internal resistance on-line measurement method, which relates to the technical field of battery detection and comprises the following steps: S1, establishing a dynamic load disturbance model of a storage battery; s2, extracting effective voltage drop component data from the noise signal by adopting an adaptive filtering method; s3, calculating equivalent internal resistance by using a complex impedance calculation method; s4, performing multi-scale internal resistance evolution analysis based on the calculated equivalent internal resistance; and S5, based on multi-scale internal resistance evolution analysis, performing fault early warning on internal resistance abnormity. According to the on-line measurement method for the internal resistance of the single storage battery, high-precision on-line measurement of the internal resistance of the single storage battery is realized through construction of a dynamic load disturbance model, multi-scale internal resistance evolution analysis and fault early warning based on the internal resistance. Compared with the prior art, the method can accurately capture the influence of the load change on the internal resistance, utilizes the multi-scale internal resistance evolution analysis to early warn the internal resistance abnormity in advance, and improves the health management capability in combination with the multi-scale analysis.

The invention relates to the technical field of remote monitoring, in particular to a remote monitoring system for power equipment, which comprises a load lag mapping module, a voltage drop rate identification module, a temperature control abnormity judgment module, a task energy consumption optimization module and a scheduling priority ordering module. According to the method, trend deviation is identified by extracting key sections of load and temperature change, an abnormal propagation path is constructed by combining continuity and directivity of a voltage change rate, an association relationship between a diffusion chain and nodes is determined, and a fault path with a time sequence recursion characteristic is extracted based on load change difference in a temperature rise process. According to the method and the system, the task type, the energy consumption trend and the communication requirement are combined to screen nodes with scheduling value, a scheduling list is dynamically generated, the response priority is synchronously adjusted, and efficient overall planning of remote monitoring node management and self-adaptive optimization of a scheduling strategy are realized.

The invention relates to a high-precision temperature sensor based on complementary dynamic element matching and a zoom analog-to-digital converter and a working method, and belongs to the technical field of sensor improvement, and the sensor comprises an analog front end, an analog-to-digital converter, a digital rear end and a control logic. An improved chopping technology is adopted, and one clock signal is adopted to control two sub operational amplifiers, so that the output stability and precision of the analog front end are improved. A complementary dynamic element matching technology is utilized, errors caused by voltage drop at the two ends of a switch are reduced, the influence of channel charge injection is counteracted, a scaling type analog-to-digital converter design is provided for an analog-to-digital conversion part, and balance among power consumption, speed and precision is achieved. According to the method, a 10-bit successive approximation register analog-to-digital converter is used for measuring a numerical value and a change trend, and the numerical value and the change trend are analyzed, so that the expression effects of a current mirror structure, a transistor, a filter and the like are evaluated, the aging of the transistor is found in advance, and a clear direction is provided for future design improvement.

A low voltage ride through control method for a grid-forming inverter based on dynamic internal potential adjustment comprises the following steps: detecting a voltage per unit value of a grid-connected point in real time, and comparing the voltage per unit value with a threshold value to judge a voltage drop event and trigger low voltage ride through control; dynamically calculating active and reactive power reference values through a reactive compensation equation and an active current limiting equation according to the voltage amplitude and the power reference value before falling during the ride-through period; inputting the active reference value into a virtual rotor motion equation to generate a reference phase, and outputting a phase reference signal in combination with a dual-mode phase compensation controller; superposing the reactive reference value with the reference voltage through a reactive voltage regulating ring to generate a voltage amplitude reference signal; synthesizing an internal potential according to the phase and the amplitude reference signal, and obtaining an inductive current reference value through virtual impedance control and current amplitude limiting; and finally, a driving signal is generated through the current inner loop controller and the modulation module. According to the invention, overcurrent can be effectively inhibited, rapid reactive power support is provided, and synchronous stability and smooth transition in a fault period and a recovery process are ensured.

The invention discloses a converter collaborative current limiting method based on adaptive virtual impedance and a power loop, and the method comprises the steps: firstly building an equivalent impedance model of a converter and a power grid, analyzing the steady-state and transient characteristics of fault current, and extracting key parameters for current limiting design; when it is detected that the voltage drop of the grid-connected point exceeds a threshold value, a self-adaptive virtual impedance link is automatically put into use, and virtual resistance and reactance values are dynamically calculated according to the variation amplitude of voltage or current, so that the virtual resistance and reactance values are proportionally adjusted along with the fault degree; and when the system voltage returns to normal, the virtual impedance automatically quits, and the control continuity is ensured. Then, the active and reactive power reference values are dynamically corrected according to the voltage drop depth, a power reference signal matched with the voltage amplitude is generated, it is guaranteed that power output does not exceed the limit, and the voltage supporting capacity is improved. Finally, real-time current-limiting control of the converter and stable operation of the system are realized on the premise of not switching the control mode through the synergistic effect of the virtual impedance ring and the power ring. The method has the advantages of being high in response speed, excellent in current limiting effect, good in control continuity and the like, and is suitable for fault current limiting and voltage support control of the grid-forming converter.

The invention relates to the field of lithium battery detection, and particularly discloses a lithium ion battery fault detection method, which comprises the following steps of: firstly, acquiring total current data of a battery pack in real time, and judging the current running state of a battery system according to the total current of the battery pack and the duration time; and when the battery system is in a standing state, calculating the voltage drop rate and the temperature rise rate of each single battery in a preset time window, and comparing the voltage drop rate and the temperature rise rate with corresponding thresholds to realize self-discharge detection and fault identification. And when the battery system is in a charging or discharging state, a deep learning algorithm is further introduced, temperature-pressure coupling time sequence fluctuation characteristics of each single battery are extracted, and temperature-pressure coupling time sequence fluctuation state consistency analysis is performed on each single battery, so that intelligent detection of faults of the single batteries in the charging and discharging process is realized. According to the method, the abnormal temperature and pressure fluctuation of the single battery in the charging and discharging process can be effectively captured, so that early warning and accurate positioning of a fault are realized.

The invention relates to the technical field of industrial process control, and discloses an intelligent optimization control method of an alkaline water hydrogen production system, which comprises the following steps: a controller synchronously acquires real-time voltage, current and temperature data of an electrolytic bath; theoretical reversible voltage is calculated according to a Nernst equation, ohm voltage drop is eliminated, and a bubble additional impedance value representing the bubble coverage degree is analyzed; performing differential processing on the change rate of the bubble additional impedance value to generate a flow feed-forward control instruction, combining a feedback control instruction based on temperature deviation to synthesize a target rotating speed instruction, and driving an alkali liquor circulating pump to adjust the flow speed; according to the method, the bubble impedance observation model is constructed, so that zero-delay sensing and decoupling control over the state of bubbles in the electrolytic cell are achieved, hysteresis of single temperature feedback is eliminated, and the problems of actuator saturation and model aging drifting are solved.

The invention discloses a cooperative ride-through control method for a new energy flexible direct current transmission system under a receiving end fault, and relates to the technical field of flexible direct current transmission, and the method comprises the steps: periodically collecting the grid-connected point voltage of a receiving end converter station, an output active current reference value, and the real-time data of the online impedance estimation of a converter station side; calculating the minimum possible true values of the converter station side equivalent reactance and the short circuit point voltage; calculating a reactive current reference value and an active current reference value of the flexible DC receiving end converter station after the fault occurs; calculating the input time of the energy consumption resistor; the reactive current reference value, the active current reference value and the energy consumption resistor input moment are sent to a receiving end converter station; and when the receiving-end converter station detects that the voltage drop of the grid-connected point meets the low-voltage crossing starting condition, the receiving-end converter station enters a low-voltage crossing control mode and starts control, and the receiving-end converter station performs corresponding adjustment. By the adoption of the method, the rising speed of the direct-current voltage is reduced fundamentally, the input time or the input frequency of an energy consumption device is reduced, and the economical efficiency of fault ride-through is improved.

The present application provides a method and system for predicting the remaining service life of an IGBT device, comprising: simulating an IGBT device power cycle aging experiment, collecting conduction voltage drop historical data on the basis of the experiment, and respectively obtaining a model parameter empirical value and a model parameter estimated value on the basis of the conduction voltage drop historical data; constructing a first state weight on the basis of the current operation state, and performing smooth adjustment on the model parameter estimated value on the basis of the model parameter empirical value and the first state weight to obtain a parameter correction result; and establishing a state transition equation on the basis of the parameter correction result, and predicting the remaining service life of an IGBT device on the basis of the state transition equation. Use of the present application can improve the accuracy of prediction of the remaining service life of the IGBT device.

The invention discloses a main station big data-based low-voltage transformer area topology hierarchy identification method and system, and the method comprises the steps: constructing a multi-dimensional voltage feature vector through the voltage time sequence data, collected by a main station side, of a transformer area general meter and a user ammeter, and forming an electrical feature matrix through feature extraction; and on the basis, judging the station area affiliation and the phase line affiliation of the user electric meter through similarity calculation. Then, generating a stable consensus cluster based on multi-time window clustering and the copolymerization matrix, and mapping the cluster into a virtual electric meter box node; constructing a minimum spanning tree and carrying out directionalization to obtain an initial radial topological structure; further introducing an electrical consistency criterion based on correlation of voltage drop and subtree current, performing multi-candidate structure optimization on the preliminary topology, and finally obtaining an optimal transformer area topology hierarchical structure consistent with a physical rule; high-precision automatic identification of the low-voltage transformer area topology can be realized without manual participation, and effective support is provided for digital operation and maintenance of a power distribution network.

The invention relates to the technical field of network construction type converter control, in particular to a network construction type converter fault ride-through method and system based on dynamic virtual resistance control, and the method comprises the steps: adding a control link based on virtual impedance in a network construction type converter control system; detecting the actual value of the power grid voltage, and judging whether the power grid voltage drops or not; detecting the current amplitude output by the grid-forming converter in real time, and judging whether the current amplitude exceeds a set value or not; if one of the two conditions is met, a virtual impedance control link is started: stage-type current limiting control is performed on the virtual resistor, and the size of the virtual resistor provided by the network-forming converter to the power system is adjusted in real time along with the amplitude of the fault current; and when the power grid voltage recovers and the current amplitude is smaller than the set value, the virtual resistor staged current-limiting control exits. According to the invention, the amplitude limiting of the fault current in the fault ride-through of the network-constructed converter can be realized, so that the fault ride-through capability and transient stability of the network-constructed converter are improved.

The invention discloses a Schottky diode and a manufacturing method thereof, the Schottky diode comprises a substrate, an epitaxial layer, a cathode layer, a plurality of first ion implantation regions, a plurality of first grooves, a second barrier metal layer and an anode layer, the plurality of first ion implantation regions and the plurality of first grooves are arranged in a main junction region, a first ion implantation region is arranged at the bottom of the first groove, a PN junction is formed between the first ion implantation region and the epitaxial layer, a second ion implantation region is arranged at the bottom of the first groove, a PN junction is formed between the second ion implantation region and the epitaxial layer, and a first barrier metal layer is arranged on the side wall of the first groove; the second barrier metal layer is arranged on one side, far away from the substrate, of the epitaxial layer, is positioned in the main junction region and is connected with the first ion implantation region and the first barrier metal layer; the anode layer is disposed on the second barrier metal layer. Through the above design, the reverse leakage current of the Schottky diode can be greatly reduced, and the forward conduction voltage drop of the Schottky diode can be reduced.

The invention provides a fault ride-through control method for a network construction type converter, and belongs to the technical field of energy storage converters and the like. The method comprises the following steps: firstly, measuring PCC voltage and power grid side current, calculating amplitudes of the PCC voltage and the power grid side current, and then judging whether the PCC voltage drops below a set threshold value or not; if not, keeping the active power reference and the voltage amplitude reference unchanged; and if so, performing active power reference modification: judging whether a current limiting strategy is triggered, if not, locking the PCC voltage reference as a measured value, and if so, gradually decreasing the PCC voltage reference by an increment value based on the measured value. According to the invention, accurate evaluation of the existence of the stable equilibrium point is realized; meanwhile, an improved fault ride-through control method is provided, active power reference and voltage amplitude reference are dynamically modified, so that the grid-forming converter is transited to a new stable balance point during a fault period, and current limiting, transient synchronization stability improvement, PCC voltage source characteristic maintenance and maximum fault current output can be taken into account.

The invention provides a chip power supply network compensation method and device, equipment, a storage medium and a program, relates to the technical field of integrated circuits, in particular to a chip and circuit design technology, can be applied to an application scene of chip test optimization, and the method comprises the following steps: determining a dynamic power consumption violation area of a current power supply network of a target chip; performing compensation priority classification on the dynamic power consumption violation area according to the voltage drop violation distribution information of the dynamic power consumption violation area to obtain a violation priority classification area; and determining a local power supply network compensation strategy of each violation priority classification area according to the compensation priority of the violation priority classification area. According to the embodiment of the invention, the efficiency and precision of chip power supply network compensation can be improved.

The invention discloses an active island detection method and system based on harmonic impedance characteristic identification, and the method comprises the steps: analyzing the harmonic impedance difference of grid-connected points in a grid-connected state and an island state, and building a state criterion based on resonant frequency deviation and impedance amplitude through the comparison of the frequency response characteristics of island impedance and grid-connected impedance; fitting the grid impedance into an RLC parallel model in a selected frequency band, and mapping the topological difference of the power grid into a parameter difference; embedding a low-voltage ride-through strategy in the control of the voltage source converter, and adjusting reactive current in a grading manner according to the voltage drop degree of a grid-connected point; fundamental waves and harmonic waves are separated through a cascade notch filter, two synchronous harmonic waves are injected into the system through constant current control, and it is ensured that injection signals of a multi-voltage source converter are in the same phase in a phase locking link; and solving an overdetermined equation set based on the double-frequency response data to identify RLC parameters, setting an island criterion, and synchronously completing island judgment in a low-voltage ride-through time window. Detection precision is improved, dynamic response is optimized, and power generation efficiency is improved.

The invention relates to the technical field of power distribution fault positioning, in particular to a power distribution single-phase earth fault positioning method and device based on multi-source information fusion. The device comprises a data acquisition module, a fault line selection module, a grading emergency module, a fault positioning module and a parameter optimization module. According to the method, the zero-sequence current is monitored in real time, the dynamic change curve is generated, the fault line is accurately identified in combination with amplitude and phase characteristics, electrical parameters, environmental factors and load importance are fused to carry out comprehensive risk assessment and start a hierarchical response mechanism, and the fault point of the fault line is accurately positioned by adopting a voltage drop method. And the monitoring frequency and the decision threshold value are adaptively adjusted according to the fault characteristics and historical data, so that response lag and insufficient precision of a traditional fault positioning method are avoided, full-flow intelligent management from fault detection, accurate positioning to parameter self-optimization is realized, the accuracy and efficiency of fault processing are improved, and safe and stable operation of a power grid is ensured.

The invention relates to the technical field of motor control, and discloses a voltage compensation stable management system for a vortex oscillator motor, and the system comprises a detection unit which is used for collecting a bus current signal; the processing unit is used for performing differential operation on the bus current signal to determine a current change rate, judging that a load sudden change working condition is entered when the current change rate exceeds a preset threshold value, and further querying a load response coefficient according to a preset feature table and calculating a voltage compensation increment; and the driving unit is used for adjusting the phase shift angle of the excitation voltage according to the voltage compensation increment. According to the invention, by identifying the load working condition in real time and executing feedforward compensation, the instantaneous voltage drop caused by load switching is eliminated, the voltage steady-state characteristic of a motor driving link is maintained, the rotation speed fluctuation is effectively inhibited, and the dynamic response capability of the system under the variable load working condition is enhanced.

The invention relates to the technical field of micro-grid control, and provides an island micro-grid distributed control method, system and device and a storage medium. Comprising the following steps: performing voltage compensation gain and frequency compensation gain calculation based on droop control output of each distributed power generation unit, droop control output of all neighbor distributed power generation units, and a voltage dynamic tracking error and a frequency dynamic tracking error which are obtained by calculating a microgrid global recovery target to obtain secondary adjustment output; and after corresponding items in the droop control output and the secondary regulation output are summed to generate comprehensive reference output, voltage synthesis is carried out according to the comprehensive reference output to obtain voltage regulation output for output control of a corresponding inverter. Based on a distributed regulation and control mechanism for cooperatively calculating the compensation amount of each power generation unit by using neighbor information and a global recovery target, the dynamic response speed and the power distribution precision can be improved, voltage drop and frequency deviation caused by load disturbance are effectively eliminated, and rapid recovery is realized.

The invention relates to the technical field of voltage sensitivity photovoltaic stability regulation and control of a power distribution network, in particular to a multi-parameter photovoltaic grid-connected voltage stability control method, system equipment and a medium, and aims to improve the transient modeling precision by constructing a second-order equivalent transient model of a photovoltaic system and decoupling a mapping relation between phase-locked loop parameters and equivalent inertia and damping; quantifying a transient stability boundary under voltage disturbance based on a phase-locked loop sensitive parameter, and determining a photovoltaic power angle critical safety threshold; for the whole voltage fluctuation process, dynamically and cooperatively regulating and controlling phase-locked loop parameters according to the voltage and frequency of the power grid; equivalent damping and inertia suppression oscillation are enhanced in the voltage drop period, inertia acceleration recovery is reduced while high damping is maintained in the voltage recovery period, rated parameters are reset in the steady state, the transient stability of the system for coping with voltage sag is remarkably improved, and the risk of power angle instability is avoided.

The invention provides a display device which is characterized in that two cascaded gate drive circuits are spaced by X gate drive circuits, and the phase difference of first clock signals corresponding to the two cascaded gate drive circuits is (X + 1) H, the effective level of a first gate control signal corresponding to the compensation transistor and the effective level of a second gate control signal corresponding to the data transistor are at least partially overlapped; the effective level of a second gate control signal corresponding to the data transistor is located between two first effective levels of a first clock signal applied by a gate drive circuit corresponding to the compensation transistor, and the phase difference between the effective level of the second gate control signal corresponding to the data transistor and one of the two first effective levels is larger than 0 and smaller than (X + 1) H, therefore, in the same sub-pixel, the effective level of the second gate control signal corresponding to the data transistor does not coincide with the moment when the voltage drop of the first gate control signal corresponding to the compensation transistor occurs, and the problem of uneven display is solved.

The invention belongs to the technical field of lithium batteries, and particularly relates to a lithium-rich manganese-based positive electrode material and a preparation method and application thereof. The preparation method comprises the following steps: mixing a metal salt solution, a precipitator and a complexing agent, and carrying out coprecipitation reaction on an obtained coprecipitation reaction precursor solution to obtain a lithium-rich manganese-based precursor; the metal salt solution comprises a manganese element, a cobalt element and a nickel element; and mixing the lithium-rich manganese-based precursor, a lithium source, an auxiliary agent and a dispersing agent, and calcining to obtain the lithium-rich manganese-based positive electrode material, the auxiliary agent comprises a nitrogen source or a nitrogen source and a carbon source. The first discharge specific capacity, the rate capability and the cycling stability of the lithium-rich manganese-based positive electrode material can be improved, and the problems of capacity fading, discharge voltage drop and dynamic delay in an electrochemical reaction process are solved.

The invention relates to the technical field of fuel cell control, and discloses a control method of a hydrogen fuel system controller, which comprises the following steps: in response to a system shutdown instruction, controlling a DC / DC converter to maintain operation and request a preset scavenging current, and consuming residual reaction gas in a flow channel and a pipeline by using an electrochemical power generation reaction in an electric pile; meanwhile, hydrogen-cut air-down operation is executed, and the average single voltage of the electric pile is collected in real time; when it is monitored that the average monomer voltage is reduced to be below a preset anti-corrosion safety threshold value, the DC / DC converter is controlled to be disconnected, and mechanical purging is started. A time sequence interlocking mechanism of electrochemical energy depletion and mechanical purging is established, a high-potential retention path in the shutdown process is blocked from the physical and chemical source, and the safety of the shutdown is improved. Reverse polarity corrosion caused by a hydrogen-air interface effect is avoided, and the service life of the galvanic pile is prolonged.

The invention discloses a doubly-fed induction generator fault detection method combining a sliding-mode observer and a bilateral cumulative sum algorithm, and the method comprises the following steps: designing a doubly-fed induction generator rotor current sliding-mode observer based on the combination of a novel reaching law and a doubly-fed induction generator state equation; carrying out stability and convergence analysis on the designed novel reaching law by adopting a Lyapunov stability theory; and the fault detection method of the doubly-fed induction generator is designed in combination with the optimized bilateral accumulation sum algorithm. A rotor current sensor fault, an input interference voltage fault, a voltage drop fault and a stator turn-to-turn short circuit fault are introduced. The rotor current tracking performance of the designed sliding-mode observer under different doubly-fed induction generator faults is verified by using a residual value obtained by comparing a doubly-fed induction generator rotor current value estimated by the sliding-mode observer with an actual rotor current output value; and meanwhile, the reliability of the designed doubly-fed induction generator fault detection method based on the optimized bilateral cumulative sum algorithm is verified. The doubly-fed induction generator fault detection method combining the sliding-mode observer and the bilateral cumulative sum algorithm has the advantages of being high in tracking precision and accurate in fault state characterization, meanwhile, weak fault features can be effectively converted into digital signals to be output, and faults of the doubly-fed induction generator are detected.

The invention relates to the technical field of battery modeling and photovoltaic energy storage systems, and discloses a self-adaptive battery modeling method for direct current bus voltage support of an optical storage system. The method comprises the following steps: establishing a basic model comprising a direct-current voltage source, an ohmic internal resistor and an RC polarization network; the voltage drop depth is obtained by monitoring the voltage of the direct-current bus in real time and used for correcting the polarization resistance; and performing differential operation on the voltage to obtain a change rate so as to adjust the polarization capacitance. And dynamically optimizing the battery model by combining correction results of the two, and realizing adaptive updating of model parameters. And applying the optimization model to the optical storage integrated grid-connected system. The adaptability of the battery model to the dynamic working condition is improved.

The invention discloses a method for preventing needle burning during testing of breakdown voltage of a discrete device. According to the method, in a test loop comprising a probe card and a test source, a voltage-withstanding module is connected in series between the probe card and a low-potential end of the test source. The voltage-withstanding module comprises a detection resistor Rx and a voltage-withstanding switching device connected with the detection resistor Rx in parallel. When the test current I is applied, if the current is increased abnormally due to poor contact and the like, and the voltage drop on the detection resistor Rx is greater than or equal to the starting voltage VT of the voltage-withstanding switching device, the voltage-withstanding switching device is switched on, the test current I is shunted, and the current flowing through the probe card is reduced, so that the probe is prevented from being burnt. The breakdown voltage of the tested device is calculated by measuring the total voltage V at the two ends of the test source and subtracting the voltage drop (I * Rx) on the detection resistor Rx, and the test accuracy is ensured. The method can effectively protect the probe card and improve the test reliability and efficiency.

The invention relates to the technical field of semiconductors, in particular to a source heterojunction contact semiconductor structure and device and a manufacturing method, the semiconductor structure comprises a gate structure, a body region structure, a source structure and a drain structure, and the source structure comprises a polycrystalline silicon source contact layer; the semiconductor structure comprises a body region structure and a polycrystalline silicon source contact layer, the body region structure is surrounded by the gate structure, a source contact region is arranged in the body region structure, the polycrystalline silicon source contact layer is in contact with the source structure through the source contact region so as to form a heterojunction diode with the source structure, and the heterojunction diode is a freewheeling diode of the semiconductor structure. The drain electrode structure is located on one side, back to the gate electrode structure, of the body region structure; the semiconductor structure can be a SiC MOSFET structure, reverse conduction voltage drop during follow current of the SiC MOSFET can be greatly reduced, and conduction loss and loss caused during switching are reduced.

The invention discloses a stator assembly, a compressor and refrigeration equipment, and relates to the technical field of motors. The stator assembly comprises a stator core formed by stacking a plurality of amorphous alloy sheets, the stator core comprises a yoke part, a tooth part and a shoe part, and the stator core is formed by stacking a plurality of amorphous alloy sheets, so that the iron loss of the stator assembly can be reduced. For a motor, the area of a stator slot is expected to be as large as possible to increase the winding wire diameter so as to reduce copper loss, and the smaller the minimum width of a tooth part is, the better is, but the smaller the width of the tooth part is, the more likely to cause magnetic field saturation. In order to reasonably design the minimum tooth width of the tooth part so as to reduce the problem of magnetic voltage drop increase caused by magnetic field saturation, the minimum tooth width Wt of the tooth part is set in a range of 2piD / 9Q to 2piD / 3Q, so that the area of the stator slot can be effectively increased, the problem of magnetic voltage drop increase caused by magnetic field saturation can be improved, the magnitude of current can be reduced, and the service life of the stator slot can be prolonged. The working efficiency of the motor is improved.

The invention relates to the technical field of virtual impedance self-adaptive control of energy storage converters, in particular to a virtual impedance self-adaptive control method of a grid-forming type energy storage converter, which comprises the following steps of: acquiring three-phase voltage and current of a grid-connected point in real time; performing phase-locked loop processing and coordinate transformation to obtain a d-axis voltage, a q-axis voltage and a current under a synchronous rotating coordinate system; calculating instantaneous power, and obtaining active power and reactive power; virtual resistance and virtual inductance are calculated according to power fluctuation through an adaptive algorithm; the virtual impedance equation generates a voltage drop compensation signal; and superposing the compensation signal and the reference voltage to generate a new modulation wave, and inputting the new modulation wave into the pulse width modulation module to realize power oscillation suppression and stable operation. According to the method, the problems between damping enhancement and loss reduction in network construction type control are solved, the dynamic and steady-state performance of the converter is improved, and a key technical support is provided for large-scale and high-reliability application of the network construction type energy storage converter in a novel power system.