3244 results about "DC-BUS" patented technology

The invention relates to the technical field of energy storage device grid-connected control, and discloses an energy storage device grid-connected control method and device based on a distributed energy storage system, and the method comprises the steps: carrying out the initialization and operation data collection of the distributed energy storage system which integrates an inverter and a plurality of energy storage devices, and obtaining the operation state data of the system; performing multi-scale decomposition of the output power of the renewable energy source to obtain power component data; calculating a target power value of each energy storage device, and constructing an energy storage power distribution scheme; constructing a non-linear state feedback controller, and adjusting the voltage of the DC bus to obtain converter control parameters; dynamically selecting an optimal PWM scheme, and generating a PWM control instruction for controlling an inverter; and inputting the PWM control instruction into the model prediction controller, and calculating a charging and discharging power instruction and a grid-connected control signal of the energy storage equipment so as to realize grid-connected operation control of the distributed energy storage system, so that accurate control and optimal scheduling of the distributed energy storage system are realized.

The invention discloses a photovoltaic hydrogen production power supply topological structure based on MPPT and a control method, and relates to the technical field of renewable energy electrolysis hydrogen production, and the photovoltaic hydrogen production power supply topological structure mainly comprises a photovoltaic power module, a direct current bus, a water electrolysis hydrogen production unit, an energy storage unit and a control unit. The photovoltaic power modules are connected in parallel to the direct current bus through the independent DC / DC converter, and are matched with the automatic identification and scheduling functions of the control unit, the system operation strategy is automatically adjusted when the modules are newly added or faults exit, and plug-and-play, fault isolation and power reconstruction of the photovoltaic power modules can be supported; the duty ratio change step length of the DC / DC converter is limited when the current rapidly fluctuates due to the change of the photovoltaic output power, the current change rate of the electrolytic cell stack is effectively controlled, the service life protection of the electrolytic cell can be considered, the high modular access capability is achieved, multi-source collaborative scheduling is supported, and bus voltage stabilization and system current sharing optimization can be achieved.

The invention relates to the technical field of flexible direct-current power transmission, in particular to a centralized local energy storage modular multilevel converter MMC-CLES topology which comprises three phase units, each phase unit comprises an upper bridge arm and a lower bridge arm, and each upper bridge arm and each lower bridge arm comprise a bridge arm reactor arranged at one end, close to a power grid, of the bridge arm; a plurality of identical sub-modules SM which are connected to a power grid through a bridge arm reactor; the upper bridge arm and the lower bridge arm form a symmetrical structure; an energy storage sub-module is arranged at the position where the three-phase unit is directly connected with the direct-current bus. According to the invention, the control system is simplified, and the hardware cost and the control complexity are reduced. Voltage stress and current stress are smaller, higher power can be borne, and the high-power capacitor is suitable for being applied to high-power occasions. And moreover, due to the symmetrical layout, the control method is relatively simple, soft switching can be realized, and the power divider can be used as a multi-port component unit.

The invention relates to a reliability evaluation method and system for a flexible AC / DC power distribution network containing an optical storage system in the field of flexible AC / DC power distribution networks. The method comprises the following steps: collecting photovoltaic data, energy storage data, AC / DC bus data and the like in real time; constructing a multi-time scale dynamic topology model, and establishing a failure probability distribution function; load flow calculation based on an improved forward-backward substitution method; adopting an N-1 + N-1-1 composite fault screening strategy to simulate a typical disturbance scene; establishing a vulnerability evaluation matrix to calculate power failure probability and other indexes; designing an optimal scheduling strategy based on model predictive control; multi-time-scale reliability evaluation is carried out; and outputting an evaluation report and a topology reconstruction suggestion. The system comprises a data acquisition unit, a dynamic modeling unit and the like, and an evaluation and analysis unit is internally provided with an algorithm module and is configured with an FPGA acceleration card. The method breaks through the limitation of traditional steady state evaluation in the technology level, improves the load flow calculation speed in the calculation efficiency level, reduces the operation cost in the application value level, improves the energy storage efficiency, and provides support for reliability evaluation of a novel power system.

The utility model provides a battery cluster-level optimizer and an energy storage system. The battery cluster-level optimizer comprises a high-voltage box and a cluster-level control unit, the high-voltage box comprises a switch module and a DCDC module; the first end of the switch module is connected with a direct current bus of an energy storage converter in the energy storage system, and the second end of the switch module is connected with a corresponding battery cluster in the energy storage system; a first end of the DCDC module is connected with the DC bus, and a second end of the DCDC module is connected with a corresponding battery cluster in the energy storage system; and the cluster-level control unit is respectively in communication connection with the switch module and the DCDC module, and is used for controlling the switch module to be closed and controlling the DCDC module to be started when the battery cluster needs to be subjected to electric quantity equalization. According to the battery cluster level optimizer, high-power equalization processing can be carried out on all the battery clusters when the electric quantities of the battery clusters are greatly different, so that rapid equalization among the battery clusters is realized.

The invention belongs to the technical field of equipment energy-saving control, and particularly discloses and provides an energy-saving control system based on a direct-current bus system, which comprises a direct-current bus framework module, an equipment state acquisition module, an equipment state analysis module and an energy flow control module. According to the method, the direct current bus voltage and the multi-dimensional operation data of the equipment motor are collected in real time, the motor power state space model is constructed by means of the Kalman filter, and the power sudden change probability of the future preset time period is accurately predicted. And meanwhile, an energy distribution strategy is dynamically adjusted in combination with the total power demand generated by the production schedule and according to the braking type and the power sudden change probability. The defect that dynamic power difference cannot be tracked through fixed threshold value feed-forward compensation in the prior art is effectively overcome, so that bus energy deposition is avoided, braking energy is distributed according to needs, meanwhile, it can be ensured that the braking energy can be recycled timely and correctly, and energy waste caused by misjudgment is reduced.

The invention discloses a multi-mode switching control method suitable for a hydrogen-electricity combined energy storage system, and the method comprises the steps: carrying out the coupling of a plurality of control units through a DC bus, and obtaining a system architecture; according to the operation mode of the system, coordinating the power output of the energy storage unit by using a dynamic collaborative optimization method based on a virtual synchronous machine technology and a variable droop coefficient, and introducing a dynamic energy distribution model and a dynamic energy distribution constraint to obtain a power balance framework of the energy storage unit; performing collaborative optimization and joint optimization on a plurality of energy storage units in the power balance framework by using the optimization model based on the cooperative game and the dynamic power regulation model to obtain a joint dynamic balance mechanism; and iteratively optimizing and improving the combined dynamic balance mechanism by using a distributed dynamic optimization algorithm to obtain the hydrogen-electricity combined energy storage system. The invention relates to a hydrogen-electricity combined energy storage control technology, and solves the technical problems that an existing hydrogen-electricity combined energy storage system is difficult to coordinate and insufficient in dynamic response in the multi-mode switching process.

The invention relates to the field of fault detection, and discloses a fault online diagnosis method for a low-speed large-torque motor control system, and the method comprises the steps: collecting the multi-dimensional parameters of the three-phase current of a motor, the voltage of a DC bus, the position of a motor rotor, the speed of the motor rotor, and the temperature of a radiator based on a sensor group; carrying out data preprocessing on the collected multi-dimensional parameters to remove noise interference; extracting fault features related to current, voltage, rotor motion and temperature from the preprocessed data; a dynamic threshold value is constructed based on fault features, non-fault parameter fluctuation and fault abnormity are distinguished through multi-feature correlation analysis, and online fault diagnosis is achieved; and finally, outputting a diagnosis result containing the fault type and the fault early warning information. Through multi-dimensional parameter acquisition and dynamic correlation diagnosis, the comprehensiveness and accuracy of fault diagnosis are improved, the false alarm rate is effectively reduced, and the method can adapt to the complex working conditions of load fluctuation and rotating speed switching of the low-speed large-torque motor.

The invention relates to the technical field of power electronics, in particular to an inverter load feed-forward compensation method and system based on dynamic hysteresis regulation. The method comprises the following steps: acquiring an instantaneous load current signal of an inverter system; wherein when the load current suddenly changes, the bus voltage on the direct current bus fluctuates; performing low-pass filtering on the instantaneous load current signal to extract a direct current component of the load current; determining a dynamic hysteresis limit value according to the instantaneous load current signal, the direct current component and the amplitude adjustment coefficient; comparing the instantaneous load current signal with a historical current feed-forward signal, updating the historical current feed-forward signal according to a comparison result and a dynamic hysteresis limit value, taking the updated historical feed-forward current signal as an updated feed-forward current signal of the current control period, generating a compensation current based on the updated feed-forward current signal, and outputting the compensation current to the current control period. And the compensation current is applied to the corresponding direct-current bus so as to suppress bus voltage fluctuation caused by load abrupt change.

In an ACDC power supply, voltage balance of each DC bus is achieved when power is unbalanced without using an additional balancing circuit or a multi-winding commercial transformer. The ACDC power supply includes an AC-DC converter ACDC, a primary side DC capacitor C1, an isolated DC-DC converter DCDC, and a secondary side DC capacitor C2. Each phase has m cells (m: an integer of 2 or more). A DC bus V is connected in series or in parallel to a plurality of secondary side DC capacitors C2. dc21 , V dc22 Multiple DC buses V dc21 , V dc22 The voltage is supplied to the load or power source. When a power imbalance occurs due to the load or power source condition, the voltage is output while maintaining the voltage balance between the secondary DC voltage and the primary DC voltage of each cell.

The invention discloses a port shore power direct-current system topological structure with a super capacitor. The port shore power direct-current system topological structure comprises a port power grid, a wind power unit, a photovoltaic power generation unit, a direct-current bus, a super capacitor bank, a ship power storage unit and a shore bridge feedback load. The port power grid, the wind power unit, the photovoltaic power generation unit and the super capacitor bank are respectively connected to the direct current bus through a first bidirectional AC / DC converter, a unidirectional AC / DC converter, a non-isolated DC / DC converter and an isolated DC / DC converter; the DC bus is connected to the ship power storage unit and the shore bridge feedback load through the bidirectional DC / DC converter and the second bidirectional AC / DC converter. The invention further discloses a seaport integrated energy system optimal scheduling method considering the ship demand response under the multi-time scale. According to the method, firstly, an electricity-heat-hydrogen coupling system model is established, and then optimization scheduling is carried out through day-ahead and intra-day optimization scheduling models. The ship docking power utilization efficiency can be effectively improved, the loss is reduced, the on-site absorption of port new energy is promoted, and the stability and reliability of the system are improved.

The power conversion device provided by the invention comprises a direct current end, a positive direct current bus, a negative direct current bus, a positive bus capacitor, a negative bus capacitor, at least three inverter bridge arms, a switch unit, a controller, filter inductors corresponding to the at least three inverter bridge arms one by one, a filter capacitor and an alternating current end. And the third end of each inverter bridge arm sequentially passes through the filter inductor, the filter capacitor and the switch unit corresponding to each inverter bridge arm and then is connected with the midpoint of the bus. The controller controls the switch unit to be switched off or the impedance of the switch unit to be increased when the voltage of the power grid is smaller than or equal to a first voltage threshold value; and after the switch unit is switched off or the impedance of the switch unit is increased, the modulation wave of each inverter bridge arm is controlled to be the modulation wave after the first common-mode modulation signal is superposed on the initial modulation wave of each inverter bridge arm, so that the amplitude of the modulation wave of each inverter bridge arm is increased. Furthermore, not only can the loss of the switching tube in each inverter bridge arm be balanced, but also the problem of common-mode oscillation caused by modulation wave change can be improved.

The invention relates to a light storage integrated system and a control method, the system comprises a direct current bus, a photovoltaic access unit, an energy storage unit, a power conversion system and an energy management system, the energy storage unit and the photovoltaic access unit are accessed to the direct current bus, and the energy storage unit is provided with a plurality of SOC parameters including a lower discharge limit SOCmin, an upper charge limit SOCmax and an off-grid recovery threshold SOCon; the energy management system configures an energy management strategy in each mode through a plurality of SOC parameters set by an energy storage unit, realizes intelligent control and mode switching in a grid-connected mode and an off-grid mode, and in the grid-connected mode, preferentially utilizes photovoltaic power to supply power to a load, switches to an anti-countercurrent mode after the stored energy is fully charged, and dynamically limits the photovoltaic power to avoid countercurrent; in the off-grid mode, the power conversion system is controlled to operate in a VF mode, and photovoltaic power reduction is triggered when set conditions are met. Compared with the prior art, the method has the advantages that the countercurrent suppression efficiency is improved, and the system safety, reliability and stability are enhanced.

A multiple input converter for outputting power from AC power or a battery to positive and negative direct current (DC) buses is provided. The multiple input converter includes at least one bridge arm unit and a bidirectional DC-DC conversion unit. The bridge arm unit corresponds to one phase of the alternating current (AC) power and includes an upper and lower bridge arms that can independently form a two-level converter. In a battery mode, the upper and lower bridge arms discharge power from the rechargeable battery to the positive and negative DC buses, and the bidirectional DC-DC conversion unit discharges power from the rechargeable battery to the positive and negative DC buses or balances voltages of the positive and negative DC buses. In a mains mode, the bridge arm units are connected to the AC power. The bidirectional DC-DC conversion unit determine whether to charge or discharge according to load conditions.

The invention discloses a current reconstruction method for sampling of double Hall current sensors of a permanent magnet synchronous motor, relates to a current reconstruction method, and aims to solve the problems that the cost and the capacity of a control system are increased and a peripheral circuit is more complicated due to the fact that three Hall current sensors need to be adopted for current sampling in a traditional method. The method comprises the following steps: step 1, installing a Hall current sensor H1 and a Hall current sensor H2; step 2, setting sampling moments of the Hall current sensor H1 and the Hall current sensor H2; 3, setting the minimum sampling time of the Hall current sensor H1 and the Hall current sensor H2; 4, current reconstruction is carried out according to the current values is1, is2 and i0 obtained by sampling of the Hall current sensor H1 and the Hall current sensor H2, and the current values of the A phase, the B phase and the C phase are obtained. The invention belongs to the technical field of common direct current bus type open winding permanent magnet synchronous motor control.

The invention provides a railway flexible traction system based on multi-source fusion. The system is composed of a central control unit, a V / v traction transformer unit and a multi-port flexible interconnection unit. The V / v traction transformer unit comprises a first power supply arm, a second power supply arm and a third power supply arm, the input ends of the V / v traction transformer unit are connected with a public power grid, the first and second power supply arms are connected to the multi-port flexible interconnection unit, and the third power supply arm provides passive support for a traction network. The multi-port flexible interconnection unit comprises a two-phase rectification module, a photovoltaic power generation module, an energy storage module and a single-phase inversion module which are commonly connected to a DC bus. The central control unit adjusts the output power of the multi-port flexible interconnection system and the control strategy of the single-phase inversion module in real time so as to realize flexible consumption of new energy and improvement of power supply stability. The system has the advantages of compatibility, cost effectiveness, new energy access and consumption, power supply reliability improvement, electric energy quality optimization, high adaptability and the like, and is suitable for upgrading and reconstruction of newly-built railway lines and existing railway lines.

The invention discloses a VSG-VDG-based autonomous control method and device for an AC-DC hybrid micro-grid interconnection converter. The equipment comprises a direct-current micro-grid, an alternating-current micro-grid and an interconnection converter connected with the direct-current micro-grid and the alternating-current micro-grid. The direct current microgrid is provided with a direct current side VDG control module which is used for controlling a direct current converter to adjust direct current power supply output by collecting internal voltage and current signals; the AC micro-grid is provided with an AC side VSG control module which is used for controlling on-off of a switching tube of a three-phase full-bridge inverter by collecting internal voltage and current signals so as to adjust AC three-phase voltage output. The interconnection converter is provided with an interconnection converter control module which is used for connecting the direct-current bus and the alternating-current bus through the bidirectional interface converter and adjusting energy balance in the subnet through bidirectional energy flow. According to the method, the robustness of the AC / DC micro-grid system is enhanced, and the fault self-healing capability of the system under extreme conditions and the transient and steady-state stability of a controlled system are improved.

The present invention provides a battery energy storage parallel equalization converter topology and a control method therefor. The battery energy storage parallel equalization converter topology comprises a series-connected battery energy storage parallel equalization converter, a main converter, and a plurality of groups of filter inductors; in the main converter, the input side of a DC / DC or DC / AC converter is connected in parallel to a parallel voltage-stabilizing capacitor, and the output side of the DC / AC or DC / AC converter is correspondingly connected to an AC or DC source load; the series-connected battery energy storage parallel equalization converter comprises a plurality of groups of small-capacity DC / DC converters and a common DC bus capacitor; the output sides of all the small-capacity DC / DC converters are connected in parallel by means of the common DC bus capacitor to form a common DC bus; the input side of one group of small-capacity DC / DC converters is connected in series to the input side of the main converter, and the input sides of other groups of small-capacity DC / DC converters are connected in series to a battery pack by means of the filter inductors, respectively. According to the present invention, in a battery charging and discharging process, only a small amount of power flows through the converter, reducing the capacity requirements of the converter, and reducing the transmission efficiency.

The invention discloses a modulation method of a three-level inverter, electronic equipment and a storage medium, and the modulation method comprises the steps: calculating a voltage difference value between the voltage at the two ends of a lower capacitor and the voltage at the two ends of an upper capacitor; respectively calculating the product of the voltage difference value and each phase current to obtain a plurality of midpoint balance judgment components, and determining a midpoint voltage compensation component according to the symbols of all the midpoint balance judgment components; performing proportional equalization processing on the neutral-point voltage compensation component to obtain a neutral-point voltage balance component; and superposing the neutral-point voltage balance component and the obtained zero-sequence voltage compensation component to an original modulation signal of the three-level inverter to obtain a target modulation signal. In the invention, a proportion control link is added for the loop injected with the common-mode component, so that a space can be created for injecting the zero-sequence component for the direct-current bus, the balance of the neutral-point voltage and the suppression of the zero-sequence circulating current are realized, the circulating current consumption is effectively reduced, and the electric energy quality and the transmission efficiency are improved.

The invention relates to the technical field of building electrics, and particularly provides a control method and system of an optical storage direct flexible system. The control method comprises the following steps: acquiring power load data of a target building within a preset time; acquiring illumination meteorological data in the preset time; obtaining a power load prediction curve according to the illumination meteorological data and the power load data; based on the power load prediction curve, constructing a control relationship between the direct current bus voltage at the grid-connected part of the optical storage direct-flexible system and the total grid-connected power; and based on the control relationship, performing power regulation according to the voltage change condition of the direct current bus. According to the invention, when the real-time power deviates from the predicted optimal load value, such as the inflection point, the optical storage direct-current flexible system can automatically deploy the power of the energy equipment connected to the direct-current bus. And system power response is completed according to the flexible capacity potential of the equipment, so that the system operation state tends to be economically optimal.

A converter system, e.g., for vehicle-to-vehicle charging, includes galvanically-isolated modular first and second converters having the same maximum voltage rating, a direct current (DC) voltage bus interconnecting the converters, and an electronic controller. An input voltage to the DC bus is converted into an output voltage via switching control signals to the modular converters. The system's voltage rating may equal the maximum of the input and / or output voltage, or it may equal the maximum input voltage and be about 50-percent of the maximum output voltage. The maximum input and output voltages may be equal. When the voltage rating is about 50-percent of the maximum input voltage, capacitors may be connected in parallel with the modular converters on an input side thereof. Switching circuits may be connected to the bus to control the conversion of the input voltage via switching control signals.

The application describes a supply unit (20) for a DC consumer (50). The supply unit (20) comprises: - a DC connection (21) for connection to the DC load (50) - a first AC connection (22) which is connected to a DC bus (26) via a first AC / DC converter (24), - a second AC terminal (23) designed for connection to a second AC voltage (U2), which is connected to the DC terminal (21) via a second AC / DC converter (25), - an energy storage device (29) which is connected to the DC bus (26) via a first DC / DC converter (27), - a second DC / DC converter (28) that connects the DC bus (26) to the DC port (21) and can be operated in a current-supplying manner with respect to the DC port (21), and - a control unit (30) for controlling the supply unit (20). The supply unit is characterized in that - the first DC / DC converter (27) is designed as a bidirectional DC / DC converter and the control unit (30) is configured to operate the first DC / DC converter (27) in a voltage-controlling manner with respect to the DC bus (26), and - the first AC / DC converter (24) is designed as a bidirectional AC / DC converter and the control unit (30) is configured to operate the first AC / DC converter (24) in a voltage-regulating manner with respect to the first AC terminal (22). The application further describes procedures for operation and start-up as well as an electrolysis plant with such a supply unit (20).

The invention discloses a motor control method and device and a household appliance, and the method comprises the steps: detecting the load current of a motor, and adjusting a modulation mode for controlling the motor through employing a first modulation strategy or a second modulation strategy according to whether the load current of the motor is greater than a preset threshold value or not. According to the motor control system adopting the scheme, the motor can be controlled by adopting different modulation modes according to different conditions, the harmonic content of direct current bus current can be effectively reduced, a bus capacitor with a smaller capacitance value can be selected in the design of the control system, the cost of the control system is further reduced, and the control efficiency is improved. Therefore, the efficiency and the cost of the control system can be considered.

In one embodiment, a method includes receiving DC bus voltage conditions of multiple AC to DC converters of an Input-Series-Output-Parallel power converter during a rectification stage; detecting a peak voltage of each of the DC bus of the multiple AC to DC converters has reached a first threshold voltage, and a Phase Loop Lock locked signal; upon detecting that the PLL locked signal, enabling a first voltage regulation to charge an AC to DC output of each of the multiple AC to DC converters to reach a first reference voltage; determining operating conditions including a load condition and an output voltage condition of multiple Dual Active Bridge (DAB) converters, and a monitored voltage of each of the multiple AC to DC converters; enabling a second voltage regulation of each of the multiple DAB converters to charge a DAB output to reach a second reference voltage based on the operating condition.

The invention discloses a cascade module non-intrusive monitoring method and system, and the method comprises the steps: obtaining a voltage signal of a DC bus in a preset time window length, obtaining a voltage fluctuation time domain signal, carrying out the signal conversion of the voltage fluctuation time domain signal through employing fast Fourier transform, carrying out the extraction, obtaining a plurality of main frequency components, and carrying out the extraction of the main frequency components; obtaining capacitance attenuation degree data according to each main frequency component, then judging whether the coupling strength index is related to the capacitance attenuation degree or not according to voltage fluctuation data of adjacent sub-modules of the direct current bus, and if yes, performing feature extraction on fluctuation coupling information by using a prediction neural network to obtain a monitoring feature vector, the optimized non-intrusive monitoring model is obtained through the monitoring feature vector, the optimized non-intrusive monitoring model is used for analyzing the voltage fluctuation data of the direct-current bus, the capacitance attenuation degree is obtained, and the accuracy and reliability of capacitance attenuation monitoring are improved through the method.

The invention discloses a DC bus interference anomaly detection method based on a dynamic local outlier factor algorithm. The DC bus interference anomaly detection method is especially suitable for real-time operation state monitoring of a complex power system. Aiming at the limitation that a traditional anomaly detection method is high in calculation complexity and limited in detection precision in high-dimensional time series data processing, optimization is carried out on the basis of an outlier detection theory, a dynamic mode updating algorithm is provided, the algorithm evaluates outlier characteristics of time series data through local density, and the detection precision of the time series data is improved. The global calculation overhead is obviously reduced, and the real-time performance and the detection efficiency of the system are improved. Compared with a traditional method, the method consumes manual intervention, is high in detection precision and strong in early warning, can be widely applied to the field of health assessment and intelligent operation maintenance of power equipment, and shows a good engineering application prospect.

The invention belongs to the field of power distribution network energy storage power flow optimization, and provides a multi-feeder shared energy storage type power flow controller and a control method thereof.The multi-feeder shared energy storage type power flow controller comprises a power flow adjusting module which is composed of a plurality of power flow adjusting half-bridge modules sharing a direct current bus, and each power flow adjusting half-bridge module is connected with one feeder; the power flow regulation half-bridge module is connected in series among the plurality of feeder lines; the shared energy storage module is connected with a plurality of feeder lines through a power balance half-bridge module, so that energy interaction between the shared energy storage module and the plurality of feeder lines is realized; according to the multi-feeder shared energy storage type power flow controller provided by the invention, through a designed control method, power flow control and shared energy storage of connected multi-end feeders can be realized on the premise of stable operation, and flexible, networked and shared transformation of a power distribution system is assisted; and the resource utilization rate, regulation and control flexibility and power supply reliability of the power distribution network are improved.

The invention provides an arc resistance characteristic-based segmented modeling method of a fuse for a direct current networking system, and relates to the technical field of common direct current bus system design, and the method comprises the steps: calculating the real-time arc resistance data of the fuse according to the continuously collected short-circuit voltage and short-circuit current at the two sides of the fuse in a short-circuit test process, and forming an arc resistance curve; intercepting an arc resistance curve from the peak moment of the short-circuit current to the slope descending moment of the arc resistance curve to obtain an arc starting stage arc resistance curve, and intercepting an arc resistance curve from the slope descending moment to the moment when the short-circuit current is zero to obtain an arc burning stage arc resistance curve; respectively carrying out data fitting according to the arc starting stage arc resistance curve and the arcing stage arc resistance curve to obtain a sectional arc resistance curve equation; and taking the arc resistance curve equation as a control signal to build and obtain a fuse simulation model based on the controlled resistor. The method has the advantages that the arc resistance curve is divided into two sections, the corresponding arc resistance curve equation is designed, the simulation precision is higher, and the method can be better suitable for different working conditions.

The invention provides a power factor correction method and system for AC-DC conversion of a server power supply, and relates to the technical field of server power supplies, and the method comprises the steps: collecting an input AC signal and a DC bus output signal, calculating a real-time power factor value, constructing a compensation function based on the power factor value, and calculating a deviation value; and generating a compensation parameter matrix through recursive calculation, processing a direct current output signal by adopting an adaptive filtering algorithm, fusing the direct current output signal with the compensation parameter matrix, calculating to obtain a current adjusting signal and a duty ratio adjusting signal, and accurately adjusting a power factor.

A bidirectional on-board charger includes a direct current bus, two bus capacitors, a power factor correction circuit, and a controller. The power factor correction circuit includes: a first bridge arm; and three second bridge arms, separately connected in series between the positive electrode and the negative electrode of the direct current bus. The controller is configured to: control the first switch (K1) to be turned off, and control at least one of the second bridge arms to output a direct current to charge a power battery; or control the first switch (K1) to be turned on, and control a midpoint of at least one of the second bridge arms to output an alternating current to supply power to an alternating current load. A Vehicle power system and an electric vehicle are further disclosed. The charger reduces circuit costs.