1725 results about "Bus voltage" patented technology

The invention discloses a CPLD-driven IGBT short-circuit current dynamic monitoring method and system, and relates to the technical field of power electronics, and the method comprises the specific steps of S100 real-time data acquisition, S200 dynamic threshold calculation, S300 short-circuit state judgment, S400 rapid protection execution, and S500 fault data recording and uploading. Accurate and prospective judgment of the short circuit state of the IGBT is achieved, two stress parameters including the direct-current bus voltage and the junction temperature serve as independent variables, when the bus voltage rises, the voltage stress borne by the IGBT in the turn-off period is increased, meanwhile, the current peak at the short circuit moment is more remarkable, early warning is conducted in advance by dynamically lowering the threshold value, and therefore the short circuit state of the IGBT is accurately judged. According to the mechanism, the monitoring system does not simply respond to the occurred overcurrent, but can pre-judge the safety boundary of the device under the current working condition, so that intervention is implemented before the current really reaches a dangerous peak value, and a protection blind area under a severe working condition is effectively avoided.

The invention discloses a micro-grid power control method, system and device based on fuzzy modulation and a storage medium, and relates to the technical field of intelligent grid integration of a photovoltaic system and a micro-grid, and the method comprises the steps: firstly obtaining the real-time power data of a photovoltaic system, carrying out the control processing through fuzzy logic, and calculating a reference instruction; according to the reference instruction, hysteresis time is dynamically adjusted through modulation hysteresis control, and an inverter switching signal is generated; converting direct current into alternating current based on the switching signal and a power switching device, injecting the alternating current into the micro-grid, calculating active and reactive power reference values, ensuring that the system operates according to a unit power factor, and giving active power to the reference value; according to the method, the power control precision and adaptability of the micro-grid are improved, excessive switching of the inverter is avoided, loss is reduced, the service life is prolonged, power matching and stable transmission are achieved, reactive loss is reduced, bus voltage is stabilized, harmonic waves can be reduced, the electric energy quality is improved, and efficient and stable operation of the micro-grid is guaranteed.

The invention relates to the technical field of electric energy conversion control, and discloses a multi-source load auxiliary power supply power balance control system, which comprises a sampling module, a control module and a modulation module, the sampling module obtains parallel converter branch current and direct current bus voltage; the control module determines a weight by utilizing physical associated association of a bus voltage change gradient and branch current change polarity, corrects a dynamic slope factor determined by a current change rate according to the weight, and performs upper limit clamping on the dynamic slope factor according to a bus voltage margin; according to the invention, the rigid restriction of droop control logic is eliminated, the power deviation generated by asymmetry of feeder impedance is automatically offset while the bus voltage stabilization precision is maintained, and the convergence speed and the certainty of the system during violent load switching are improved.

The invention relates to the technical field of power distribution automation auxiliary power supply control, and discloses an intelligent power distribution circuit system for a digital ring main unit, which comprises a transient voltage gradient induction bridge circuit, a hardware signal processing circuit, a power switch unit and a controlled energy release unit, according to the system, a transient voltage gradient induction bridge circuit is used for collecting a primary side bus voltage change rate signal, a hardware signal processing circuit carries out derivation operation on an induction signal and compares the induction signal with a voltage gradient threshold value, and a power switch unit is blocked at the moment that the voltage abnormally drops so as to cut off a load current path. According to the invention, a hardware parameter direct mapping mechanism is utilized to realize microsecond transient protection response, and the physical decoupling of protection logic and digital software is realized by balancing bus potential pulse caused by sudden unloading of a load through the inherent dehumidification resistor in the multiplexing cabinet.

The invention relates to the field of intelligent control of electromagnetic appliances, and provides a control method and system for online fault diagnosis of a magnetic latching relay, and the method comprises the steps: responding to an external control instruction, collecting real-time bus voltage and real-time environment temperature data, constructing environment state characteristics through a magnetothermal coupling algorithm, and generating an initial PWM drive duty ratio; pulse modulation voltage is loaded, a current sampling sequence is collected, a current change rate sequence is obtained through moving average filtering and electromechanical coupling decoupling, extreme value searching is executed to extract counter electromotive force distortion characteristics, and a dynamic current sequential sequence is generated; a fusion input tensor is constructed, armature state probability distribution is output through a gating circulation unit, and a real-time energy compensation instruction is generated in a displacement interval before closing; and according to the real-time energy compensation instruction, respectively generating an enhanced driving waveform, a delayed driving waveform or a vibration driving waveform. According to the method, multi-mode physical characteristic perception and depth time sequence deduction are fused, and online fault diagnosis and active intervention closed loop of the magnetic latching relay are realized.

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

The invention is suitable for the technical field of resonant converters, and provides a starting control circuit and a resonant converter. The starting control circuit comprises a feedback module, a comparison selection module and a logical operation module, the comparison selection module is electrically connected with the feedback module and the logical operation module, the feedback module is used for being electrically connected with the output end of a resonant conversion circuit in the resonant converter, and the logical operation module is used for being electrically connected with a driving circuit in the resonant converter. According to the starting control circuit provided by the embodiment of the invention, the resonant capacitor voltage constraint threshold value which is gradually enlarged along with the starting process can be constructed, smooth establishment of resonant capacitor direct current bias is realized, the fluctuation amplitude of the resonant capacitor voltage is limited, the problem that the total bus voltage is applied to the resonant inductor in a traditional scheme is avoided, and the starting control circuit is suitable for a high-voltage power supply. Finally, the resonance current peak value in the starting stage is effectively suppressed, and the impact of current stress on core devices such as a switching tube and a resonance inductor is reduced.

The invention discloses a grid-connected inverter control method, system and device and a medium. The method comprises the steps of obtaining a power grid operation parameter, a system power instruction and a direct current bus voltage provided by a photovoltaic side hybrid energy storage system; a virtual inertia parameter is dynamically adjusted through an active-frequency control loop of the virtual synchronous machine in combination with an adaptive inertia algorithm, and a virtual rotor angular speed and an active power reference value are obtained through calculation according to a second-order motion equation of the synchronous generator; in combination with a reactive power instruction, a virtual internal potential amplitude is calculated according to a reactive-voltage droop relation through a reactive-voltage control loop of the virtual synchronous machine; and generating a three-phase voltage reference signal of the grid-connected inverter through synchronous rotation coordinate transformation. According to the invention, the dynamic performance, the operation efficiency and the grid-connected stability of the system under complex working conditions are obviously improved.

The invention discloses a bus voltage multi-dimensional real-time monitoring and analyzing method, system, equipment and medium, and belongs to the technical field of power system monitoring and fault prediction.The method comprises the steps that high-frequency synchronous sampling is conducted on bus voltage signals, discrete time sequence voltage signals are obtained and preprocessed, preprocessed voltage signals are obtained, and the discrete time sequence voltage signals are obtained; the method comprises the following steps: synchronously extracting multi-dimensional characteristic parameters of voltage, obtaining a characteristic parameter set, calculating a health degree index comprehensively representing a voltage state by utilizing a dynamic weighted fusion algorithm based on the characteristic parameter set, calculating an abnormal degree of a current value according to a historical data sequence of the health degree index, and performing fault grade judgment according to the abnormal degree. And performing trend extrapolation based on the health degree index and the historical data sequence of the key parameters in the characteristic parameter set, and generating predictive maintenance suggestions. According to the method, the crossing from passive alarm to predictive maintenance is realized, and the intelligent level and the operation and maintenance reliability of state monitoring of the power system are remarkably improved.

The invention relates to the technical field of bidirectional PCS, and discloses a bidirectional PCS converter multi-target power balance optimization method and system based on model predictive control. According to the method, real-time operation parameters are analyzed by using a first-order lag initial model, prediction of power disturbance in a plurality of control periods in the future is realized, power balance optimization is converted from passive response to active pre-judgment, and a linear time-varying prediction model is constructed, so that the real-time performance of power balance optimization is improved. According to the method, the evolution trajectory of the direct current bus voltage in a period of time in the future is predicted, the power balance optimization behavior is continuous and prospective through a rolling optimization mechanism of prediction, evaluation and preferential selection, and meanwhile, the three targets of ensuring voltage stability, reducing switching loss and suppressing current harmonic content are fused into power balance optimization, so that the power balance optimization efficiency is improved. The problems of control hysteresis and target singleness existing in a traditional control method are solved, and quick and accurate power balance control of the bidirectional PCS is realized.

The invention relates to the technical field of power electronic control, and provides a soft start control method for a three-phase PFC (Power Factor Correction), a PFC controller and a power supply system.The soft start control method comprises the steps that when a PFC start instruction is received, an initial target voltage value is set as an actual value of current bus voltage; maintaining the initial target voltage value for a first preset duration; after the initial stable state, sampling in real time to obtain the actual value of the current bus voltage, and calculating the absolute value of the voltage difference between the actual value of the current bus voltage and the current target voltage value; judging whether the absolute value of the voltage difference is smaller than or equal to a preset trigger threshold value; if yes, adding a preset voltage step value to the current target voltage value; if not, keeping the current target voltage value unchanged; and recursive control of the current bus voltage is executed circularly until the updated current target voltage value reaches the final target voltage value. According to the mode, the starting rapidity and the stability of the boosting process are balanced.

The invention relates to the technical field of logistics warehouse storage equipment, in particular to a speed reduction control method for a high-speed motor driven hydraulic system, which comprises the following steps: S1, the output torque of a high-speed motor is transmitted to a gear pump through a motor shaft, a planetary reducer and a planet carrier in sequence to drive the gear pump to work; s2, acquiring a three-phase current instantaneous signal and a direct current bus voltage signal, and performing preprocessing and frequency spectrum conversion to determine a current frequency spectrum; s3, in the current frequency spectrum, extracting an energy value in a preset frequency band with the meshing frequency and harmonic waves of the planetary gear as the center, and calculating to obtain a disturbance characterization value of the planetary gear; s4, determining a torque smooth adjustment coefficient according to the planet wheel disturbance characterization value; and S5, dynamically adjusting a dynamic response parameter of a torque control ring of the high-speed motor according to the torque smooth adjustment coefficient. The problems that in the prior art, a high-rotating-speed motor and a hydraulic pump are not matched in rotating speed, and mechanical disturbance is difficult to restrain are solved.

The invention discloses a dynamic virtual impedance control method for multi-machine parallel connection of a network construction type energy storage converter, and belongs to the technical field of power electronics. The method aims to solve the problem that accurate reactive power distribution, circulating current suppression, dynamic response and voltage precision are difficult to consider in a multi-machine parallel system through fixed parameter virtual impedance. A dynamic adjustable virtual impedance module is introduced into the voltage outer loop output end of each converter, and virtual resistance and virtual inductance are calculated in real time based on locally measured output current, bus voltage change rate and adjacent machine reactive power deviation information; and the average reactive power of the system is estimated through a phase synchronization mechanism under the condition of no communication so as to realize multi-machine cooperation. According to the method, the reactive power distribution error is less than 5%, the bus voltage drop is less than 3%, the high-frequency circulating current is controlled within 5% of the rated current under all working conditions, and the dynamic performance and robustness of the system are remarkably improved.

The invention relates to the technical field of ship electric energy storage, and discloses a ship distributed electric energy storage and distribution balance control system which comprises a plurality of distributed storage units, a direct current bus, a plurality of power conversion modules and a dynamic balance control module. The dynamic balance control module is used for collecting the voltage deviation value of the direct current bus and the current response rate and the charge state parameter of each storage unit and determining a transient charge deviation compensation value, and the system determines the transient power flux of each node according to the current response rate and the charge state parameter. And dynamic linear calibration of feedback gain is realized based on the charge deviation compensation value so as to adjust the power output flow rate of each storage unit, the charge throughput of the direct current bus is balanced through real-time hedging of the surplus or deficient state of the transient charge of the bus, voltage oscillation during ship propulsion load switching is effectively inhibited, and the reliability of the ship propulsion load switching is improved. And the transient stability of the bus voltage is maintained.

The invention provides a generator and battery power distribution method and device based on model prediction control, and belongs to the technical field of power distribution. The method provided by the invention comprises the following steps: loading a preset dynamic model library; generating and calibrating a total load power prediction sequence based on the flight plan and the rotor aerodynamic power model; calling the dynamic model library to predict and control the rolling optimization to output the optimal power instruction sequence of the generator; in the rolling optimization execution process, bus voltage dynamic characteristics are monitored in real time, a graded response mechanism is started based on a turboshaft engine dynamic model when load sudden change occurs, and the power of a generator and the power of a battery are adjusted; in the load abrupt change response process, rolling optimization is executed again based on the adjusted power and the corresponding system state, meanwhile, feed-forward compensation is carried out on the bus voltage deviation, and the voltage is controlled to be within a stable interval set by rolling optimization by adjusting the power of the generator; and circularly executing until the flight task is finished, and determining the generator power and the battery power.

The invention discloses a solar photovoltaic power generation and energy storage integrated communication machine room and an energy management and multi-mode refrigeration control method thereof, and belongs to the field of solar photovoltaic power generation green low-carbon communication machine rooms. The communication machine room takes an optical storage all-in-one machine and a unified direct-current bus as a core, photovoltaic power is connected to the direct-current bus through DC / DC, stored energy is connected to the direct-current bus through bidirectional DC / DC, commercial power is connected to the direct-current bus through AC / DC, a bus voltage stabilizing module is configured, and photovoltaic power supply priority, residual power charging and gap energy complementation are achieved. The energy management method comprises the steps of collecting power and a charge state to generate a state quantity, distributing the power according to priorities and issuing a control instruction. According to the refrigeration control method, the refrigeration mode or the mixed mode of the heat pipe and the compressor is switched according to the outdoor temperature threshold value and the refrigeration requirement, the three-way valve, the compressor and the fan are cooperatively controlled, and hysteretic and minimum retention time constraints are adopted to restrain frequent switching. According to the scheme, the renewable energy proportion and power supply continuity are improved, refrigeration energy consumption is reduced, and temperature control of the machine room is kept stable.

The invention provides a zero-voltage ride-through control method for a self-synchronizing voltage source doubly-fed wind turbine generator, which comprises the following steps that: when the self-synchronizing voltage source doubly-fed wind turbine generator is in a transient state, a grid-side converter adopts vector control, and a rotor-side converter adopts additional virtual impedance and annular current limiting; the transient overcurrent of the grid-side converter and the rotor-side converter can be effectively suppressed, so that the continuous operation capability of the wind turbine generator in the zero-voltage ride-through period can be maintained; meanwhile, by improving the transient capacity and the transient reactive current amplitude of the converter, the transient voltage supporting capacity of the wind turbine generator during the zero voltage ride-through period can be effectively provided; when the self-synchronizing voltage source doubly-fed wind turbine generator set is in a transient state, overvoltage of direct-current bus voltage is limited by a Chopper circuit, active-priority current amplitude limiting control is adopted by a grid-side converter, parameters of a current inner ring PI controller of a rotor-side converter are optimized, energy balance of a direct-current side can be achieved in the zero-voltage ride-through period, and stability of the direct-current bus voltage is maintained.

The invention provides a grid-side current harmonic suppression method and device for a motor driving system without an electrolytic capacitor. The method comprises the following steps: determining first and second bus voltage harmonics based on bus voltage obtained by sampling and inverter switching frequency; correcting the bus voltage according to the first bus voltage harmonic wave and the second bus voltage harmonic wave so as to determine a reconstructed bus voltage; according to the second bus voltage harmonic, the reconstructed bus voltage, an inverter output three-phase duty ratio and a motor three-phase current, first and second network side current harmonic regulation and control voltages are determined based on a self-defined closed-loop controller; and adopting a motor alpha-axis correction voltage and a motor beta-axis correction voltage determined according to the first and second grid-side current harmonic regulation and control voltages to participate in motor SVPWM modulation to output the three-phase duty ratio of an inverter so as to suppress grid-side input current harmonics. According to the method and the device, factors such as motor operation conditions, bus voltage harmonic waves and digital control delay are comprehensively considered, the quality of grid-side input electric energy is improved, and disturbance to machine-side rotating speed and torque is reduced.

A converter station AC filter group circuit breaker abnormal arcing modeling analysis method comprises the following steps: firstly, carrying out time mark alignment, amplitude calibration and filtering de-noising on wave recording signals such as AC bus voltage and filter branch current to obtain high-quality input data; then, combining a primary wiring diagram, enabling an alternating current system to be equivalent to an ideal power supply and series impedance, enabling circuit breaker arcing to be equivalent to arc resistance changing along with time, and constructing an equivalent circuit model comprising the power supply, the impedance, a capacitor, an electric reactor and dynamic arc resistance; establishing a state space equation according to a voltage and current constraint relation, and performing time domain solution by adopting a two-step two-order or three-order diagonal implicit Runge-Kutta method to obtain voltage and current responses of the whole process of the fault; on this basis, the arc resistance change is inversed according to the ratio of arc voltage to current, the current zero passage is identified through the resistance symbol change at adjacent moments, and the zero passage section is smoothed; and finally, the inversion result is verified again by means of the simplified equivalent model.

The invention discloses a grading diagnosis method, system and device for a charging module and a storage medium, which are used for reducing unnecessary charging interruption and improving the adaptive capacity of the charging module to external disturbance. The method comprises the steps that when it is monitored that the voltage of a direct-current bus drops and the change rate exceeds a preset change rate threshold value, it is judged that a transient event is triggered, a triggering timestamp of the transient event is obtained, and a plurality of operation parameters at the moment before the transient event is triggered are obtained and determined as a stable baseline; evaluating a synchronous change trend of the plurality of operation parameters relative to the stable baseline, and classifying each operation parameter into a preset state label according to an evaluation result; based on the correlation among the plurality of operation parameters and the combination of the state labels, the event source category of the transient event is diagnosed, and the event source category at least comprises a power grid side sag event, a load side sudden load event and a module internal fault event; and executing a hierarchical response strategy matched with the event source category.

The invention discloses an integrated optimization method of a flywheel energy storage system. The corresponding system is formed by connecting a plurality of flywheel monomers in parallel through a direct current bus. The method comprises the steps that the real-time rotating speed, the direct-current bus voltage, the maximum charging and discharging power capacity and a power grid frequency modulation power instruction of each flywheel single body are collected; calculating current stored kinetic energy based on the rotating speed and the rotational inertia of the rotor, and normalizing to obtain an energy state index SoE; a double-layer collaborative architecture is adopted for power scheduling; at the moment of charging and discharging mode switching, the total disturbance of the system is estimated on line through a cascade expansion state observer, and feed-forward compensation is implemented in control output to suppress instantaneous fluctuation of the voltage of the direct-current bus. According to the method, the SoE is obtained by calculating the kinetic energy and normalizing the kinetic energy, so that the accurate representation of the energy storage state is realized; and voltage fluctuation can be effectively suppressed when working conditions suddenly change. The method avoids overcharge and overdischarge of individual units, guarantees high reliability and safety, prolongs the service life of equipment, and is especially suitable for power grid frequency support application in a high-proportion renewable energy access scene.

The invention discloses a humanoid robot joint motor control method with model prediction control, and relates to the technical field of robot motion control. The method is used for solving the problems of control instruction infeasibility and model disturbance caused by voltage saturation during high-speed motion. An error state space model of a joint motor system is established, and non-linear terms such as gravity are used as nominal feed-forward quantities for stripping; then, the rotating speed of the motor and the bus voltage of the driver are collected in real time, the back electromotive force is calculated, and the voltage margin is mapped into a dynamic torque physical limit value at the current moment; and meanwhile, estimating an unmodeled lumped disturbance value of the model by using an extended state observer. And finally, taking the dynamic limit as a real-time inequality constraint, introducing a disturbance value correction prediction equation, constructing and solving a quadratic programming problem, extracting an optimal compensation torque, superposing the optimal compensation torque with an inverse dynamic feedforward torque, and converting the superposed torque into a current signal to drive a motor, thereby realizing high-dynamic and high-precision robust control under the physical boundary constraint.

The invention belongs to the field of industrial control and computer data security, and particularly relates to a millisecond-level power failure data protection system for an industrial control panel. The invention discloses a millisecond power failure data protection system for an industrial control panel. The millisecond power failure data protection system comprises a core processing component, a real-time synchronous shadow memory component, a bus voltage monitoring component, a pre-entropy reduction logic control component, a nonvolatile storage component and a flight control bus arbitration component. The bus voltage monitoring assembly monitors a voltage drop trend and performs early warning, the pre-entropy reduction logic control assembly calculates a minimum data survival set according to energy entropy, the real-time synchronous shadow memory assembly constructs a synchronous shadow control domain and atomizes data, and the flight control bus arbitration assembly compulsively takes over a bus and freezes processor access at the moment of power failure. Atomized writing of data into the nonvolatile storage component is guaranteed. According to the invention, zero-delay data protection and millisecond-level hot start recovery at the moment of power failure are realized, and the data security and reliability of the industrial control equipment in a severe environment are enhanced.

The invention discloses a light-diesel hybrid energy storage system and a control method thereof, and belongs to the field of microgrids. The system comprises a photovoltaic power generation unit, a diesel generator set, a hybrid energy storage unit (a storage battery and a super capacitor), an AC / DC bus, a bidirectional AC / DC converter and a system controller. The controller executes hybrid energy storage frequency division control (without sampling load power and distributing power through bus voltage), V / f control and nine multi-mode energy management strategies, and monitors parameters such as photovoltaic output, load power, energy storage charge state and the like in real time to realize intelligent mode switching. The super capacitor preferentially responds to the pulse load, and the voltage fluctuation ratio is smaller than or equal to 5%; the service life of the storage battery is prolonged in combination with energy storage charge state threshold management; photovoltaic maximum utilization enables the system efficiency to be greater than or equal to 90%, and the diesel oil consumption is obviously reduced. The method is suitable for power grid coverage difficulty scenes such as off-network communication base stations, remote sentries and emergency power supply stations, and has high reliability and maneuverability.

The invention provides a satellite power supply system topology architecture and a maximum power point tracking control method thereof, and aims to improve the energy utilization efficiency of a solar cell array of a spinning body spacecraft under a complex illumination condition. The architecture adopts a combined topology architecture of a preceding-stage sequence switch maximum power point shunt regulation (S3MPR) circuit and a backward-stage four-switch Buck-Boost (FSBB) converter, and is suitable for a special operation environment of a spinning body spacecraft power supply system. The system adopts a bus full adjustment mode, enables the DC bus voltage to be stabilized near the maximum power point voltage of the photovoltaic array through a double closed-loop control strategy, and carries out real-time shunting adjustment on an S3MPR circuit in combination with a multi-peak maximum power point tracking (MPPT) algorithm, thereby ensuring the efficient operation of the photovoltaic array. According to the invention, high-efficiency energy tracking and stable charging can be realized under a complex illumination condition, and the reliability and the energy utilization rate of a spinning body spaceflight power supply system are remarkably improved.

The invention relates to the technical field of generator control, and discloses an intelligent vehicle-mounted high-power self-generating control method and system. The method comprises the following steps: acquiring operating parameters of a generator set, performing high-precision digital processing, realizing constant-rotating-speed control through cooperation of multiple controllers based on a rotating-speed fluctuation characteristic value, performing power factor correction through coordinate transformation and active rectification to obtain a direct-current bus voltage, performing precise voltage stabilization by adopting a multi-phase interleaving converter, and outputting the direct-current bus voltage. And finally, outputting a high-quality three-phase alternating-current power supply through space vector modulation and closed-loop feedback control. The technical problems in the prior art that the power supply quality control capability is insufficient, the intelligent level is low, the environmental adaptability is poor, the load adaptability is limited, and the maneuverability is limited are solved.

The application discloses a switch tube off negative voltage determination method and device and a switch tube driving control circuit. The switch tube off negative voltage determination method comprises the following steps: determining a first off negative voltage model and a second off negative voltage model; inputting the obtained off gate resistance, on gate resistance, bus voltage and minimum on voltage of the switch tube into the first off negative voltage model to obtain an upper limit absolute value of the off negative voltage of the switch tube; inputting the obtained off gate resistance, on gate resistance, bus voltage and maximum bearable negative voltage absolute value of the switch tube into the second off negative voltage model to obtain a lower limit absolute value of the off negative voltage of the switch tube; and determining the off negative voltage interval of the switch tube according to the upper limit absolute value and the lower limit absolute value. When the off negative voltage interval is used for negative voltage off control of the switch tube, the switch tube can be effectively prevented from being mis-opened, the switch tube can be protected, and the service life of the switch tube is prolonged.

The invention discloses an intelligent operation and maintenance and energy efficiency optimization management system for a photovoltaic power station, and relates to the technical field of energy efficiency optimization of photovoltaic power stations. The window positioning module is used for setting a dawn window; the amplitude ratio calculation module is used for calculating the amplitude ratio of the rising stage to the falling stage of the relative series resistance indicating quantity; the target parallel branch judgment module is used for screening a target branch; the total loss integral calculation module is used for calculating a total loss integral; the bus voltage adjusting module is used for adjusting voltage to reduce loss; and the operation and maintenance work order priority generation module is used for generating work order priorities based on the related parameters. According to the method, accurate identification, loss optimization and operation and maintenance scheduling of the abnormity in the dawn stage can be realized.

The invention discloses a multi-port DAB energy storage system directly connected with an elevator frequency converter bus and a cooperative control method of the multi-port DAB energy storage system, and is suitable for an elevator frequency converter direct-current bus direct-connection scene. Aiming at the defects in the aspects of elevator bus transient support, multi-branch extension and parallel operation safety access in the prior art, at least two DAB power branches are adopted, the low-voltage sides of the DAB power branches are connected into the same low-voltage direct-current source in parallel to realize current expansion, and the high-voltage sides of the DAB power branches are connected to a VFD direct-current bus through a parallel operation access switch to realize voltage expansion after being connected in series and laminated; the controller adopts fixed frequency phase shift control, and combines a two-line parallel operation or power-off time sequence and a zero-crossing residence strategy; through multi-branch phase interleaving, mutual exclusion amplitude limiting constraint, ZVS guarantee and a fault striding linkage mechanism, branch power balance, circulating current suppression and bus stable support are realized. According to the invention, the millisecond voltage of the bus can be efficiently suppressed, the response speed, the operation efficiency and the reliability of the system are improved, and the core requirements of elevator bus energy recovery and transient stability control are met.

The invention discloses a grid-connected control method and system based on a three-port energy router. The grid-connected control system comprises a photovoltaic power generation system, an energy storage system and a grid-connected inverter system, the photovoltaic power generation system adopts a perturbation and observation method and is used for performing photovoltaic maximum power generation; the energy storage system comprises a storage battery, adopts direct current bus voltage stabilization control, and is used for performing peak load shifting of energy and maintaining the direct current bus voltage; the preceding stage of the grid-connected inverter system adopts fuzzy VSG + pre-synchronization control so as to realize grid-connected and off-grid seamless following and provide voltage support; the post-stage of the grid-connected inverter system adopts double closed-loop + optimization compensation control, performs power regulation and control through weighted cooperation with a VSG double closed-loop system, and is responsible for long-term energy balance. According to the invention, photovoltaic maximum power tracking, energy storage charging and discharging coordination and grid-connected and off-grid seamless switching are realized, and the method is suitable for distributed power supply grid connection, a DC micro-grid and a novel power distribution system.