2712 results about "Current voltage" patented technology

A fault ride-through method and apparatus for a new energy transmission system, and an electronic apparatus, relating to the technical field of new energy grid connection and flexible direct-current power transmission. The method comprises: acquiring a voltage parameter of a grid-connected inverter and a voltage of an alternating-current system, the voltage parameter comprising at least one of the following: an alternating-current voltage of the grid-connected inverter, a direct-current voltage of the grid-connected inverter, and a direct-current voltage change rate; on the basis of at least one of the voltage parameter and the voltage of the alternating-current system, determining whether a low-voltage fault has occurred in a new energy transmission system; and when a low-voltage fault has occurred in the new energy transmission system, adjusting the new energy transmission system at least according to a preset adjustment method, so that the new energy transmission system carries out fault ride-through within a preset duration, the preset adjustment method comprising at least one of the following: adjusting the active current of the grid-connected inverter and adjusting the integral element of a flexible direct-current system. The problem of lack of a fault ride-through method suitable for a large-scale new energy flexible direct-current transmission system is solved.

The invention provides an alternating-current fault ride-through control method of a direct-current sending-out system and storage equipment thereof. The method comprises the steps that the operation condition of a wind power flexible direct-current system is monitored in real time; when it is detected that the direct current side voltage of the wind power flexible direct current system is larger than a set threshold value at the receiving end converter station, a direct current side energy consumption device of the flexible direct current system is started to dissipate surplus power; when an alternating current fault is detected at the sending end converter station based on the direct current side voltage, the sending end converter station is switched to a current limiting mode, a fan and a power transmission system of the wind power flexible direct current system are controlled, and surplus power is dissipated again through an unloading circuit; when the AC voltage recovers, the sending-end converter station is adjusted back to a normal mode; and power transmission of the wind power flexible direct current system is recovered. According to the invention, on the basis of the operation condition of the receiving-end and sending-end converter station direct-current voltage monitoring system, the energy consumption device, the fan, the power transmission system and other links are used for cooperative control, power can be balanced, equipment can be protected, and the system stability can be enhanced.

The invention discloses a lithium battery charging and discharging control method and system, a product and a medium, and relates to the field of charging control, and the method comprises the steps: collecting the terminal voltage and charging and discharging current data of a current battery, and calculating the state of charge and the state of health of the current battery according to the terminal voltage and the charging and discharging current data; collecting surface temperature data of the current battery, and judging whether the surface temperature data is within a preset safety interval range or not; if yes, a preset charging curve corresponding to the charge state, the health state and the surface temperature data is called from a preset battery model database, and the preset charging curve comprises a plurality of charging stages; based on the charge state, the health state and the surface temperature data, carrying out segmented correction on the charging multiplying power and cut-off voltage of the preset charging curve to obtain an optimal charging curve; and charging the current voltage based on the optimal charging curve. By implementing the method, the charging efficiency of the lithium battery can be improved.

The invention discloses a high-power all-gallium nitride LED driving power supply circuit which comprises an EMI filtering and rectifying circuit, a GaN active power factor correction circuit, a GaN half-bridge LLC resonant converter circuit and a GaN synchronous rectifying and filtering circuit. The PFC and LLC combined control module integrates a power factor correction function and a resonance circuit frequency regulation function, the GaN active power factor correction circuit is connected with the PFC and LLC combined control module to realize power factor correction, and the GaN half-bridge LLC resonant converter circuit is connected with the PFC and LLC combined control module to realize output power regulation; and a constant-current voltage-limiting feedback circuit for outputting current and voltage detection feedback is arranged between the GaN synchronous rectification filter circuit and the PFC and LLC combined control module. The advantages of high efficiency of the GaN switching tube and high working frequency of the circuit are utilized, so that power loss and heat dissipation requirements are reduced, and the efficiency and power density of the LED power supply are improved. The invention has the advantages of high efficiency, high power density, high reliability and the like.

The invention belongs to the technical field of energy storage batteries, and discloses a deep learning prediction method and device for the voltage range of a battery system. The method comprises the following steps: collecting battery operation data of a battery cluster; the battery operation data comprises single battery range data, battery cluster charging and discharging power and battery cluster total voltage data; inputting the battery operation data into a pre-trained deep learning prediction model for prediction, and obtaining a voltage range prediction result of the battery cluster in future preset time; wherein the deep learning prediction model which is trained in advance is a BiGRU (BiGRU)-Transform-LSTM (Long Short Term Memory) model. According to the method, a mixed model of three different architectures of BiGRU-Transform-LSTM is adopted, the voltage range change of the battery can be effectively predicted, the voltage range change of a period of time in the future can be predicted according to current voltage and power information, and the method has a voltage consistency evaluation function; the method facilitates reasonable planning of a charging and discharging strategy of the battery pack, prolongs the service life of the battery, and improves the safety and reliability of the battery.

The invention provides a sensorless motor stator temperature protection method, device and equipment, and relates to the technical field of motor control, and the protection method comprises the steps: obtaining the current voltage, current and rotating speed of a motor when the motor in a motor control system is in a running state, determining a corresponding temperature rise coefficient and a heat balance temperature according to the current voltage, the current current and the current rotating speed; obtaining a current estimated temperature according to the current voltage, the current current and the current rotating speed; determining a current predicted temperature according to the current estimated temperature, the heat balance temperature, the last estimated temperature and the corresponding temperature rise coefficient; and comparing the current predicted temperature with a preset protection threshold value, and performing temperature protection control on the motor according to a comparison result. A temperature sensor does not need to be installed in the motor, so that the installation difficulty and cost are reduced, the reliability and durability of the system are improved, and the risk that the sensor breaks down or is damaged is avoided.

The invention discloses a direct current control method and system for improving transient stability of a grid-connected converter, and the method comprises the steps: judging whether a power angle out-of-limit-based fault judgment module or a voltage out-of-limit-based fault judgment module has a voltage drop or phase jump fault or not when any one module judges that a power grid has a voltage drop or phase jump fault; processing an angular velocity control signal of a synchronous control link through a direct current port transient energy correction module, and performing temporary storage unbalanced power-oriented lifting and inertia correction-oriented lifting on a direct current voltage reference value; the voltage value of the direct-current port capacitor is compared with a direct-current voltage reference value, and is processed by the steady-state direct-current voltage control module to obtain a direct-current voltage control reference value; the output data of the converter at the common coupling point obtains a synchronous control signal according to a synchronous control link; and based on the synchronous control signal, an internal potential reference value is obtained according to an internal potential control link, and then a converter driving signal is generated. According to the invention, the stability problem of the grid-connected converter when the power grid has a transient fault can be effectively solved.

The invention discloses a control method and system for improving SVG (Static Var Generator) disturbance signal generation precision, relates to the technical field of SVG disturbance signal generation, and solves the technical problem that a current disturbance signal generated by an SVG is difficult to meet the dynamic precision requirement required by multi-frequency impedance measurement. According to the technical scheme, disturbance signal attenuation caused by SVG direct-current voltage control is calculated through an observer, after phase compensation, the disturbance signal attenuation and a direct-current voltage given value are superposed to serve as outer loop input of a voltage controller, and the outer loop input is subtracted from direct-current voltage feedback; an outer ring output is obtained through a voltage controller of an outer ring and superposed with an instruction current disturbance signal to serve as an inner ring input of a current controller, and SVG operation is controlled through a current inner ring controller and a PWM modulation instruction. The influence of a direct-current voltage outer loop on actual current disturbance signals is remarkably reduced, and the SVG can still output accurate actual current disturbance signals when instruction current disturbance signals of all frequencies are injected into the SVG.

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 variable-frequency reconfigurable wireless electric energy transmission system and a parameter design method, and relates to a wireless electric energy transmission system and a parameter design method. The invention aims to solve the problem that approximately constant power transmission is difficult to maintain in the prior art for relatively wide coupling coefficient fluctuation. The system comprises a full-bridge inverter circuit, a primary side compensation network, a coupling coil, a secondary side compensation network and a rectification filter circuit. The input end of the full-bridge inverter circuit is connected with a direct-current voltage source UD, the output end of the full-bridge inverter circuit is connected with the input end of the primary side compensation network, the output end of the primary side compensation network is connected with the primary side input end of the coupling coil, and the secondary side output end of the coupling coil is connected with the input end of the secondary side compensation network. The output end of the secondary side compensation network is connected with the input end of the rectification filter circuit, and the output end of the rectification filter circuit is connected with the battery load Ro. The invention belongs to the technical field of wireless power transmission.

The present invention discloses a direct-current side voltage reference value setting method and apparatus, a storage medium, and a device. During low-voltage ride-through, direct-current side operation characteristics under different power grid voltage drop conditions are carefully considered. On the basis of different power grid voltage drop conditions, a corresponding strategy is executed to reduce a direct-current voltage reference value, so that a high modulation factor can be maintained during an entire low-voltage ride-through process, switching loss of a grid-forming converter can be reduced, and output waveform quality can be improved. During high-voltage ride-through, because constant-voltage control is adopted, the grid-forming converter may lose balance points. Therefore, according to differences in power grid voltage rise amplitude, the present invention divides a direct-current side reference value setting algorithm into three conditions, and provides an algorithm for maintaining a minimum active current required to stabilize a bus voltage of the direct-current side, so as to ensure that direct-current voltage remains controllable during the entire ride-through process.

The invention provides a stable operation control method and system for a self-synchronizing voltage source centralized photovoltaic inverter, and the method comprises the steps: detecting the change rate of the DC voltage of the centralized photovoltaic inverter and the output active power of a photovoltaic panel in real time, and when the ratio of the change rate of the DC voltage to the change rate of the output active power of the photovoltaic panel exceeds a threshold value, starting the control of the stable operation of the photovoltaic inverter. A system working mode is converted from a power control mode to a voltage control mode, and a power given value and a direct-current voltage given value of a control system are adjusted in real time. A synchronous angular frequency is obtained by adding an output value of the deviation of the active power through a proportional controller and a power grid frequency value, and the phase of an output modulation voltage of a grid-connected converter is obtained after integration, so that the grid-connected power of the photovoltaic inverter is adjusted. The working points of the photovoltaic inverter can stably operate on all the working points of the photovoltaic power-voltage characteristic curve, it is ensured that the photovoltaic inverter is located at the maximum power point all the time, and then stable operation control over the self-synchronizing voltage source centralized photovoltaic inverter is achieved.

The invention discloses a control method for a composite direct-current power synchronization grid-following type converter, and belongs to the technical field of wind power grid-connected converter control. The problem that in the prior art, a traditional converter control method based on network tracking type control is low in stability due to subsynchronous oscillation easily generated under a weak power grid is solved. According to the method, the direct-current power of the grid-following type converter is collected and sequentially passes through a lead / lag link and an integral controller, then an obtained compensation item is introduced to a d-axis current reference instruction value output by a direct-current voltage loop, d-axis current and q-axis voltage are influenced, the influenced q-axis voltage serves as phase-locked loop input, and the phase-locked loop is connected with a phase-locked loop. An output grid-connected angle is directly controlled by a proportional-integral controller of a phase-locked loop link, and an angle small signal value additionally introduced by composite direct-current power synchronization is equivalent to that a network-forming type direct-current inertia synchronization link is introduced into a network-following type phase-locked loop. The method improves the adaptability of the following network type control system to the weak power grid, and can be applied to converter control.

The invention provides a direct current system for uniformly and directly transmitting offshore wind power to a land power grid in multiple regions. The topology of the direct current system mainly comprises an offshore wind power alternating current collecting-direct current sending-out system, a coastal direct current receiving end system, an inland direct current receiving end system and a coastal direct current bus, the offshore wind power alternating current collecting and direct current sending-out system is used for collecting and sending out grid connection of offshore wind power; the coastal direct-current receiving end system is used for transmitting direct-current electric energy to a coastal power grid and controlling system direct-current voltage; the inland direct current receiving end system is used for transmitting direct current electric energy to an inland power grid; the coastal direct-current bus is used for connection and electric energy exchange between the offshore direct-current line and the land direct-current line. According to the invention, the direct transmission of the electric energy of the offshore wind field to the power grids in multiple regions on land is realized, the access and consumption of the offshore wind power in the coastal and inland power grids are ensured, the offshore wind power consumption capability and power transmission capability of the power grids are improved, and the economic benefits and environmental benefits are improved at the same time.

The invention discloses a vehicle-mounted bidirectional power converter which comprises a pre-stage voltage stabilization module, a pre-stage driving circuit, a post-stage driving circuit, a post-stage filtering module and an electric vehicle battery module, the pre-stage voltage stabilization module is used for balancing circuit voltage and supporting reactive power, the pre-stage driving circuit is of a single-phase full-bridge AD-DC topological structure, and the post-stage filtering module is of a single-phase full-bridge AD-DC topological structure. The front-stage driving circuit is of a half-bridge type bidirectional DC-DC topological structure, the rear-stage driving circuit is of a half-bridge type bidirectional DC-DC topological structure, the front-stage driving circuit and the rear-stage driving circuit are connected together through a direct-current voltage-stabilizing bus, the size is small, the weight is light, a front stage and a rear stage do not interfere with each other, control is easy, the rear-stage filtering module is used for restraining direct-current side second harmonics, the harmonic quantity is prevented from influencing the stability of output direct-current voltage, and the output direct-current voltage is stable. According to the converter, a corresponding control method is designed, non-inductive decoupling control and a single-phase phase-locked loop of an improved loop filter are adopted, the phase of a power grid is accurately and efficiently obtained, and the converter works stably.

Disclosed in the present invention are a power grid impedance measurement method and apparatus. The method comprises: generating a characteristic harmonic current instruction on the basis of a harmonic-signal generation algorithm, and inputting the characteristic harmonic current instruction into a direct-current voltage feedback control loop; receiving the characteristic harmonic current instruction to generate a control signal, and performing current tracking control to obtain a harmonic current to be injected; converting an information electronic signal of a main circuit into a driving signal in a device control loop, and selecting a preset harmonic injection mode in real time on the basis of a harmonic injection target frequency; when active harmonic injection is selected, controlling the turning-on and turning-off of a switch tube, and injecting said harmonic current into a power grid; when passive harmonic injection is selected, controlling the turning-on and turning-off of an IGBT, controlling a time and a current flow direction of when a capacitor is connected to the power grid for operation, and injecting said harmonic current into the power grid; and selecting voltage and current signals to perform signal decomposition, processing and analysis, so as to obtain a power grid impedance. By means of the present embodiment, a power grid impedance is effectively measured, the disturbance to a power grid during impedance measurement is reduced, and the measurement precision is improved.

A control method and apparatus for receiving-end alternating-current fault ride-through, and an electronic device and a storage medium, which relate to the technical field of power transmission and distribution, and are used for solving the technical problems of system power imbalance, poor coordination capability, etc., in existing receiving-end alternating-current fault ride-through processes. The method comprises: determining as a faulty receiving-end converter station a receiving-end converter station in which an alternating-current fault occurs, generating an alternating-current voltage fault signal by means of the faulty receiving-end converter station, and also executing power surplus assessment, in order to obtain a surplus power value; then, transmitting the alternating-current voltage fault signal and the surplus power value to an alternating-current energy consumption apparatus; if the faulty receiving-end converter station is a receiving-end constant-voltage station, on the basis of the alternating-current voltage fault signal and the surplus power value, absorbing surplus power of an islanded power grid by means of putting the alternating-current energy consumption apparatus into use; and if the faulty receiving-end converter station is a receiving-end constant-power station, adjusting, on the basis of the surplus power value, a reference power value of the faulty receiving-end converter station by means of the faulty receiving-end converter station, and absorbing the surplus power of the islanded power grid by means of putting the alternating-current energy consumption apparatus into use.

The invention relates to the technical field of high-voltage direct-current transmission, and discloses a reactive power support control method and system for a CLCC converter under an alternating-current fault, in order to fully explore the power support potential of the CLCC, the method comprises the following steps: firstly, starting from the forced commutation process of the CLCC during the fault period, analyzing that the trigger angle and the power have the multi-quadrant regulation and control capability; secondly, a direct current operable range and a trigger angle regulation and control range are determined; a power operation domain in the range is established; then, determining a trigger angle compensation amount and a control mode by taking no influence on active power transmitted to a receiving end alternating current system as a target; according to the method provided by the invention, the direct-current voltage and the direct-current transmission power of the inverter side during the alternating-current fault period can be kept unchanged, the voltage drop of the converter bus during the alternating-current fault period can be reduced, and the quick and stable recovery of the alternating-current voltage is facilitated.

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 grids, in particular to a control method and system for an anti-resonance energy storage converter to be connected to a grid-connected system, a terminal and a medium. FFT Fourier transform is carried out on obtained current voltage and current of a grid-connected point, a complex time domain signal is decomposed into superposition of a plurality of simple sine and cosine functions, and the voltage and current of the grid-connected point are obtained; in a spectrogram, the frequency components and characteristics of the signal, including the amplitude and phase information of each frequency component, including harmonic parameters and characteristic sub-harmonics, can be clearly obtained. In the step S2, negation can be carried out on harmonic waves appearing in the grid-connected system through characteristic subharmonic waves, and deduction effect reduction is carried out on the harmonic waves. In the step S4, when the harmonic parameter still exceeds the preset standard value after the step S2 is carried out, it shows that harmonic oscillation causes a resonance phenomenon, and at the moment, the system impedance is changed by adjusting the virtual impedance of the energy storage converter, so that the harmonic oscillation can be weakened or even eliminated to a great extent.

The invention discloses a voltage out-of-limit control method and system for grid connection of a photovoltaic power generation system containing energy storage, and the method comprises the steps: building a grid connection model according to an equivalent structure diagram of grid connection of the photovoltaic power generation system containing energy storage; according to the grid-connected model, under the conditions that the line impedance is fixed and the load power is random and uncontrollable, the voltage of a grid-connected point is adjusted by controlling active power and reactive power output by an inverter; a dynamic participation factor is introduced, and the charge state of energy storage and the residual capacity of an inverter are taken into reference so as to carry out self-adaptive distribution of power. The method can effectively solve the problems of insufficient adjustment and response lag of a current power distribution network voltage out-of-limit control strategy.

The invention relates to a turn-to-turn short circuit fault diagnosis method, device and equipment for a dry-type air-core reactor, a readable storage medium and a program product, and relates to the technical field of electric power safety. By adopting the method, the initial turn-to-turn short circuit condition of the reactor can be detected in time, and the accuracy of fault diagnosis is improved. The method comprises the following steps: obtaining a reconstruction signal according to historical voltage and current data of the dry-type air-core reactor; on the basis of the reconstruction signal, constructing a Bowdrill curve, and calculating a characteristic parameter of the Bowdrill curve; calculating the change rate of the current state of the characteristic parameters relative to the health state, and obtaining the weight corresponding to the change rate through an entropy weight method; determining a standard value for judging the fault according to the change rate and the weight, and taking a target standard value corresponding to the target fault degree as a fault threshold value; and obtaining a current standard value according to the current voltage and current data of the dry-type air-core reactor, and comparing the current standard value with a fault threshold to obtain a turn-to-turn short circuit fault diagnosis result of the dry-type air-core reactor.

The invention provides an energy coordination control system and scheduling method for multi-energy complementary new energy storage, and belongs to the technical field of new energy storage and energy technology management. The data acquisition and processing module is connected with a current and voltage sensor, a power transmitter, a meteorological station sensor and a battery management system sensor, and is used for acquiring voltage, current, power, state of charge and environmental data of photovoltaic power, wind power, energy storage and load through the sensors; and sliding window filtering and wavelet de-noising processing are carried out through the embedded processor. The method has the beneficial effects that the uncertainty of wind and light output is effectively processed by establishing a layered distributed optimization architecture and adopting a method of combining multi-objective optimization and robust optimization, and the consumption rate of renewable energy sources can be remarkably improved, the net load fluctuation can be reduced and the energy consumption can be reduced on the premise of meeting various system operation constraints. Therefore, dependence on conventional fossil energy is reduced, and the economic operation level and the environmental protection benefit of the whole energy system are improved.

The invention discloses a 10kV distribution transformer on-load voltage regulation control method and system, and relates to the technical field of transformer on-load voltage regulation, and the method comprises the steps: collecting the three-phase voltage and current of a low-voltage side of a distribution transformer and a tap switch gear signal, and loading a preset voltage regulation control mode and an oscillation region parameter; based on the acquired three-phase voltage and current of the low-voltage side of the distribution transformer and the tap switch gear signal, calculating a feeder comprehensive impedance parameter and a load reactive power parameter, and outputting a transformer operation state index; according to the transformer operation state index, the voltage regulation control mode and the oscillation area rule, current voltage out-of-limit and reactive power deviation are judged, and a voltage regulation strategy triggering instruction is generated according to the judgment result; and calculating upper and lower limit values of feed line correction voltage based on the voltage regulation strategy trigger instruction, and controlling the tap switch to execute voltage regulation action. According to the method, a combined calculation scheme of feeder comprehensive impedance and load reactive power is fused, and dynamic optimization of the triggering condition of the voltage regulation strategy is achieved.

The invention discloses a vehicle charging control method and system and driving equipment, and relates to the technical field of vehicle charging. The vehicle charging control method comprises the steps that the current voltage and current of the alternating current side of a vehicle-mounted charger are monitored; in response to the fact that the current voltage is smaller than the first preset voltage, target charging current of the vehicle is determined according to the current voltage, the first preset voltage and the current current. According to the vehicle charging control method, the real-time voltage and current of the alternating current side of the vehicle-mounted charger in the slow charging process of the vehicle are monitored in real time, the charging current of the vehicle is adjusted when the voltage of the alternating current side is lower than the preset voltage, the safe charging current is provided for slow charging of the vehicle, and therefore fire disasters and other safety accidents are prevented in advance.

A direct-current conversion circuit, which is used for providing direct-current conversion between a first direct-current voltage and a second direct-current voltage is described. The direct-current conversion circuit comprises: a transformer, which comprises a primary-side winding and a secondary-side winding, wherein the primary-side winding comprises a center tap, and a first primary-side winding and a second primary-side winding, which are respectively connected to the center tap; a primary-side circuit, wherein a first side of the primary-side circuit is connected to the primary-side winding, a second side of the primary-side circuit comprises a first end, a second end, and a third end, and a first direct-current voltage is provided between the first end and the second end of the primary-side circuit; and a secondary-side circuit, wherein a first side of the secondary-side circuit is connected to the secondary side winding.

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 discloses a protocol converter giving consideration to group regulation and control and local regulation and control, and the converter comprises an archive configuration module which configures the archive information of all photovoltaic inverters and protocol converters of a photovoltaic equipment grid-connected point; the command response module responds to the data request and the regulation and control command of the photovoltaic management system; the acquisition module is used for acquiring telemetry data of all equipment at a grid-connected point and calculating total active power and total reactive power output by all inverters at the grid-connected point and adjusting capability of all the inverters; the local strategy generation module is used for generating a local voltage regulation and control strategy according to the current voltage state; and the command generation module is used for generating command judgment and regulation and control instructions. According to the invention, group regulation and group control can be satisfied, local regulation and control can be carried out, and the problem that a photovoltaic management system cannot effectively monitor photovoltaic inverter equipment due to carrier communication defects can be effectively solved.

A power conversion apparatus includes a converter that rectifies a first alternating-current voltage supplied from an alternating-current power supply that is a three-phase alternating-current power supply, a capacitor connected to an output end of the converter and smooths a first direct-current voltage obtained by rectification by the converter into a second direct-current voltage containing a first ripple, an inverter that is connected across the capacitor and converts the second direct-current voltage into a second alternating-current voltage dependent on a desired frequency, and a voltage detection unit that detects a physical quantity correlated with the second direct-current voltage, in which the second alternating-current voltage is controlled such that a second ripple correlated with the first ripple is superimposed on an output voltage from the inverter.