228 results about "Voltage limit" patented technology

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.

A method and system for protecting a battery power limit, and a storage medium are disclosed. The method for protecting a battery power limit is applied to a vehicle with a battery management system. The method includes: acquiring temperature data, a state of charge, and a cell voltage extreme value of a battery, periodically; calculating a current maximum available power according to the temperature data and the state of charge; determining a power limit coefficient according to the cell voltage extreme value, and a voltage limited power interval corresponding to the temperature data; and obtaining an actual available power that the battery management system allows the vehicle to use according to the maximum available power and the power limit coefficient. According to the method, different temperature ranges can be adapted according to logic.

The invention belongs to the technical field of impact current suppression, and relates to a method and system for suppressing the impact current of a DC bus output by a DC charger, and the method comprises the following steps: collecting the output voltage of the DC bus and the required voltage of a vehicle side, and forming a voltage sequence; calculating the change rate and the pressure difference of the two; when the change rate exceeds a threshold value or the communication time sequence is discontinuous, entering voltage limiting constraint control; determining a limiting function according to the change rate and the voltage difference and updating a voltage reference value; adjusting the output voltage according to the updated reference value; and continuously executing voltage reference value updating and output adjustment until the output and the required voltage tend to be consistent, then exiting the voltage limiting constraint, and continuously performing dynamic adjustment according to the required voltage. According to the technical scheme, through dynamic monitoring and voltage difference constraint on the bus and the required voltage, voltage limiting adjustment and reference value smooth updating during sudden change are achieved, the impact current peak value is effectively restrained, and it is ensured that the voltage is stable, the current is limited, and the system operates stably.

The invention discloses a bidirectional direct current circuit breaker which comprises an electronic branch assembly, a voltage limiting branch assembly and an energy consumption branch assembly. The electronic branch assembly is used for transferring current; the voltage limiting branch assembly is electrically connected with the electronic branch assembly in parallel so as to reduce the turn-off overvoltage of the circuit breaker; and the energy consumption branch assembly is electrically connected with the electronic branch assembly in parallel so as to be used for absorbing the energy of the circuit. According to the hybrid DC circuit breaker, the current transfer function of the hybrid DC circuit breaker can be realized through the electronic branch assembly, the voltage limiting branch assembly and the energy consumption branch assembly. Compared with a bidirectional direct-current circuit breaker based on a power electronic device in the related technology, the bidirectional direct-current circuit breaker is compact in structure, low in connection inductance and high in universality, and functional units can be configured. The problems that in the related technology, connection is complex, redesign is needed under different working conditions, and functional units are inconvenient to adjust are solved.

The invention discloses a photovoltaic string medium-voltage convergence system, and belongs to the technical field of photovoltaic power generation, the system realizes voltage level jump through a + / -1500V bipolar symmetric architecture, and a plurality of 1500V photovoltaic strings are configured to have positive electrodes and negative electrodes symmetrically arranged to form a medium-voltage convergence system with the total output voltage of 3000V. And meanwhile, the stability of the system is maintained through the midpoint high-resistance grounding device, and the voltage limitation of a traditional 1500V system is broken through on the premise of not changing the insulation and voltage resistance level (1500V) of the existing equipment. According to the scheme, the direct current side transmission loss and the cable cost are remarkably reduced, the confluence radius is expanded, existing photovoltaic modules, cables and matched equipment are compatible, and an efficient and economical confluence solution is provided for a large photovoltaic power station.

The invention relates to a rotating shaft assembly, a grounding part and electronic equipment, the rotating shaft assembly comprises a rotating shaft and the grounding part, the grounding part is arranged between the rotating shaft and a rotating shaft back cover in the electronic equipment and is electrically connected with the rotating shaft back cover and the rotating shaft to form a grounding circuit, and the grounding part comprises a voltage limiting element. When the voltage in the grounding circuit is greater than or equal to a first threshold value of the voltage limiting element, the voltage limiting element conducts the grounding circuit; when the voltage in the grounding circuit is smaller than the first threshold value of the voltage limiting element, the voltage limiting element disconnects the grounding circuit. The rotating shaft assembly is simple in structure, easy to manufacture and low in cost, the ESD grounding requirement of the rotating shaft back cover and the daily use requirement of a user can be met at the same time, the service life of a metal appearance part outside the electronic equipment is prolonged, and the use safety of the electronic equipment is improved.

The application discloses a voltage-limited overvoltage protection component with a recoverable electromagnetic drive tripping mechanism, which is composed of a voltage-limited overvoltage protector and an electromagnetic drive tripping mechanism. In a normal state, the normally closed contact of the electromagnetic drive tripping mechanism is in a closed state, which does not affect the normal working state of the voltage-limited overvoltage protector and the protection state under a normal intensity overvoltage. When an overvoltage occurs, a pulse current flowing through the voltage-limited pressure-sensitive resistor induces a current in the upper metal disc of the electromagnetic drive tripping mechanism, which is opposite to the direction of the spiral conductor coil of the lower electromagnetic drive disc, so that the upper metal disc of the lower electromagnetic drive mechanism induces an electromagnetic repulsive force with the lower electromagnetic drive disc, thereby causing the normally closed contact of the electromagnetic drive tripping mechanism to break, effectively inhibiting the continuous effect of a subsequent power frequency or direct current arc on the voltage-limited protector, prolonging the service life of the voltage-limited overvoltage protection component, and effectively realizing the safe use coefficient and prolonging the service life of the voltage-limited overvoltage protection component.

The invention relates to an electronic device (100), comprising:-a switching device (102) for switching a main current path (103), the switching device (102) having n semiconductor switching cells (102.1, 102.2,..., 102. N) connected in series, where n is a natural number other than zero,-a voltage limiting device (114) connected in parallel with the switching device (102), the invention relates to a voltage limiting device (100), comprising at least one overvoltage protection means (107) and at least one bidirectional trigger diode (109) connected in series with the at least one overvoltage protection means (107), and n overvoltage arresters (110, 110.1, 110.2,..., 110. N), each of the n overvoltage arresters (110, 110.1, 110.2,..., 110. N) being connected in parallel with each of the n semiconductor switching units (102.1, 102.2,..., 102. N) in a bijection-dependent manner.

This invention relates to a voltage limiting control method for a series-type offshore wind power DC collector system, comprising: superimposing a low-voltage DC link voltage control loop on the power control loop of the wind turbine generator-side converter, and obtaining a reference value for the d-axis component of the generator-side converter voltage. umsd_ref and q-axis component reference value umsq_ref The control signal for the generator-side converter is generated through sinusoidal pulse width modulation to maintain stable low-voltage DC link voltage while ensuring stable power output. The grid-side converter of the wind turbine adopts voltage / frequency control to obtain the d-axis reference value of the grid-side converter output voltage. uod _ ref and q-axis reference value uoq _ ref The grid-side converter control signal is generated by sinusoidal pulse width modulation. By setting the d-axis setpoint of the grid-side converter output voltage, the AC output voltage of the grid-side converter is limited, thereby controlling the DC output voltage of the wind turbine generator within the limit value.

Electrical protection device, associated electrical installation and control method The present invention relates to an electrical protection device comprising: a mechanical switch; an interruption cell (18) comprising N switching modules (32, 42), N being greater than or equal to 2, each switching module (32, 42) comprising a voltage limiting element (39, 49), each voltage limiting element having a different limiting voltage (Ulim1, Ulim2);a control unit comprising a cell control module (66), configured to control each switching module in the blocked configuration, the limiting voltages, alone and / or summed together, form at least 2N-1 distinct steps, and the cell control module is configured to control in the blocked configuration the switching module(s) whose limiting voltages form a step being the largest step less than or equal to a dielectric withstand of the mechanical switch. Figure for the abbreviation: Figure 2;

The invention discloses a power output circuit and a power output method.The power output circuit comprises a constant-current module, a constant-voltage module and a master control module.The master control module receives an external input instruction, generates a first control signal and a second control signal according to the external input instruction and outputs the first control signal and the second control signal to the constant-current module; the first control signal is output to the constant-current module, and the second control signal is output to the constant-voltage module, so as to control the constant-current and constant-voltage output of the input power supply. Through the scheme, constant-current and constant-voltage output of the input power supply is realized, 0-40A adjustable current and 1.25-6.25 V adjustable voltage can be provided on the premise that a 5V safety voltage threshold is not exceeded, and the technical effects of large-current output and wide-range voltage adjustability under strict voltage limitation are realized.

A method for operating an electrochemical stack (10) comprising a plurality of electrochemical cells (1), each cell having an anode compartment (2) with an anode electrode (6) and a cathode compartment (3) with a cathode electrode (7), wherein the anode compartment (2) and the cathode compartment (3) are separated from each other by a semipermeable membrane (8). An electrical voltage is present between the anode electrode (6) and the cathode electrode (7) during operation, with the electrochemical cells (1) being connected in series. A cell voltage monitoring unit (17) is connected to the electrochemical cells (1). The method is characterized by - Measuring electrical voltages U i using the cell voltage monitoring system (17) of n electrochemical cells connected in series, where n is greater than or equal to 2, - Comparing the measured voltages U i with a maximum voltage U exp,nand a minimum voltage U min,n , where the maximum voltage U exp,n n times the maximum possible cell voltage of a single electrochemical cell U exp is and U min,n the (n-1) times the maximum possible cell voltage of a single cell (1) plus a lower voltage limit U Limit , where U Limit the smallest cell voltage down to which operation of a single electrochemical cell (1) is to be carried out, - Output an error message if at least one of the measured voltages U i smaller than U min,n or larger than U exp,n is.

The invention discloses a field weakening trajectory tracking control method for permanent magnet synchronous motors based on enhanced model predictive current control, comprising: S1, establishing a mathematical model of the permanent magnet synchronous motor in a synchronous rotating coordinate system and determining the optimal operating trajectory in the field weakening region; S2, constructing an extended virtual voltage vector set synthesized from the basic voltage vector, and constructing a virtual voltage vector containing continuous components, excess components, and disturbance components as feedback quantities, which are adjusted by the field weakening current controller. d The shaft reference current limits the virtual voltage amplitude within the inverter output voltage limit; S3, a nonlinear extended state observer based on a nonlinear function is designed to estimate the current state and total disturbance in real time, and correct the current prediction model. The optimal voltage vector is selected through a cost function, and a switching pulse sequence is generated to drive the inverter. This invention can effectively reduce current ripple when motor parameters are mismatched and overcome the deviation of the field weakening trajectory when model parameters are mismatched.

System which includes the following: a peak current mode controller for controlling the cycle operation of a power switch in a switching power converter for controlling an output voltage to a nominal value, wherein the peak current mode controller includes a comparator (520) to generate a turn-off command in response to a comparison of a multiplied fault signal with a signal (Isense) representing an input current into an AC / DC power converter; an upper threshold voltage (VOUT-limit) matching circuit (530) configured to increase an upper threshold voltage (VOUT-limit) in response to an increase in a voltage ripple between the output voltage and the nominal value, wherein the upper threshold voltage (VOUT-limit) matching circuit (530) is further configured to decrease the upper threshold voltage in response to a decrease in the voltage ripple; a lower threshold voltage (VOUT lower limit) matching circuit (535) configured to decrease a lower threshold voltage (VOUT lower limit) in response to an increase in voltage ripple, wherein the lower threshold voltage (VOUT lower limit) matching circuit (535) is further configured to increase the lower threshold voltage in response to a decrease in voltage ripple; and a mode control circuit (525) configured to allow the comparator (520) to control the cycling of a power switch when an output voltage for the switching power converter is both lower than the upper threshold voltage (VOUT upper limit) and higher than the lower threshold voltage (VOUT lower limit), and to prevent the comparator (520) from controlling the cycling of the power switch when the output voltage is higher than the upper threshold voltage (VOUT upper limit) or lower than the lower threshold voltage (VOUT lower limit).

The invention belongs to the field of vehicle-mounted electronic product power supply, and particularly discloses a stabilized power supply output system and an output method thereof.The system comprises a voltage reference chip, a first triode, a second triode, a power MOS tube, a first resistor, a second resistor, a third resistor and a fourth resistor; the third resistor and the fourth resistor are connected in series between the power output end and the ground, the voltage dividing point is connected with the base electrode of the second triode, the emitter electrode is grounded through the first resistor, and the collector electrode is connected with the source electrode of the power MOS tube through the fifth resistor and used for adjusting the voltage stabilizing output voltage limit value according to the normal working voltage limit value of a back-stage load. When the voltage of the input end is smaller than the set voltage-stabilizing output voltage limit value, the output voltage is kept consistent with the input voltage, and when the voltage of the input end is larger than the set voltage-stabilizing output voltage limit value, the output voltage is kept at the set voltage-stabilizing output voltage limit value. The circuit can meet the requirement of a large-power load, and can still work normally when the power supply voltage changes.

The application discloses a short-circuit recovery voltage limiting method for a three-stage direct-current generator, which detects output voltage U0 of the three-stage direct-current generator and load current i L to determine the state of the load, adjusts the output state of the three-stage direct-current generator according to the state of the load by using an asymmetric half-bridge excitation topology, detects the generation output voltage and the load current to determine characteristic states such as a short-circuit state, a short-circuit recovery state and a first voltage peak falling edge after short-circuit recovery, and closes upper and lower excitation power tubes in combination with the asymmetric half-bridge during short-circuit recovery, so that the two power tubes are opened only when the first voltage peak falls to a voltage undervoltage value after short-circuit recovery, and voltage overshoot during short-circuit recovery of the three-stage direct-current generator is limited to the maximum extent, and the safety of a power supply system is ensured.

The invention provides an electric steering engine load braking control method, and belongs to the field of aircraft control. According to the method, on the premise of no current closed-loop control, the current peak value and the pumping voltage of the electric steering engine under the load braking working condition are remarkably reduced, and the impact on a controller is reduced. An electric steering engine load braking module is designed, an output voltage amplitude limiting value is dynamically adjusted through an electric steering engine speed signal, reverse voltage braking is used when the load speed is too high, the electric steering engine is decelerated and braked in advance, braking energy is reduced, and finally the braking current peak value and pumping voltage are reduced. A speed weighting calculation module is synchronously designed, and an electric steering engine speed input signal with higher signal quality is provided for a load braking module. The method realizes the suppression of the braking current and the pumping voltage of the electric steering engine under the condition of no current closed-loop control, and has the characteristics of simple algorithm, low hardware requirement and good suppression effect.

This invention discloses a constant power charge-discharge control method for vanadium redox flow batteries based on MPC-SP, applied to an energy storage control system consisting of an MPC-SP controller, a PCS, and the vanadium redox flow battery. Based on a preset SOC range, the controller dynamically and precisely adjusts the power output to the battery, increasing the power in stages as the actual SOC value of the battery increases. Simultaneously, the controller constantly monitors the battery terminal voltage Ud; when Ud reaches a voltage limit, it switches to constant voltage mode, effectively preventing battery damage due to excessive voltage. This state-based dynamic power management is far safer, more flexible, and more intelligent than traditional fixed constant power control. This invention reduces the rate of current change during the charge-discharge process of the vanadium redox flow battery, extending battery life while ensuring safety.

The present application relates to the field of motor control, and more particularly to a fault-tolerant control method, device, computer equipment and computer storage medium for open-circuit fault of an alternating current motor. The method comprises: A, under the condition of considering the change of motor cross-axis current and direct-axis current with motor rotor electric angle, constructing a fault-tolerant control optimization model, wherein the fault-tolerant control optimization model comprises a cost equation generated based on a motor torque equation and a restriction condition constituted by one or more of a fault phase current equation, a motor phase current limit equation and a motor phase voltage limit equation; and B, determining a phase current reference value at the current motor rotor electric angle by using the fault-tolerant control optimization model.

The invention relates to a system (2) for converting a first voltage (U1) into a second voltage (U2), comprising: a converter (4) provided with at least two input terminals (5), at least two output terminals (8), and at least one electronic switching branch (10), the or each branch (10) comprising two switching half-branches (16) connected in series to an intermediate terminal (8), the at least one half-branch (16) comprises at least one switching member (19), the or each switching member (19) comprising a controllable electronic switch (20); and means (6) for controlling the or each electronic switch (20) of the or each branch (10); the converter (4) further comprises, for the or each electronic switch (20), a passive voltage limiting component (12) connected to said electronic switch (20), thermally coupled to said electronic switch (20) and having a negative temperature coefficient.

The application discloses a kind of MTPA-weak magnetic feedforward control method, system based on model parameter updating, storeable medium, it is related to motor control field.The present application includes two stages: MTPA stage control and weak magnetic stage control respectively.Specifically, on the basis of MTPA control, judge whether current point is in the overlapping region of voltage limit circle and current limit circle, if meet then continue to execute MTPA mode, if not meet then jump to weak magnetic region control, according to the interrelation of target torque and voltage limit region, current limit region, real-time solution updates the current operating point of weak magnetic area.In the present application, the smoothness of two-stage transition and the responsiveness of the system under varying conditions are improved.In the case of inductance parameter variation, the present application can update the current operating point based on inductance variation in real time, effectively suppress the working condition fluctuation, and show good application prospect.

The application relates to the technical field of semiconductor bridge electrostatic discharge protection and current protection, and discloses an electrostatic discharge and current protection circuit of a semiconductor bridge, which comprises an ESD protection circuit, a current protection circuit and an NMOS connected in parallel, the ESD protection circuit comprises a bidirectional transient suppression diode and a capacitor connected in parallel, the bidirectional transient suppression diode clamps a transient high voltage by breakdown conduction, the voltage is limited in a safe range, the capacitor reduces a voltage rising rate and suppresses overshoot by shunting and absorbing a transient current, the NMOS provides a low-resistance discharge path, and the voltage and current impact applied to the semiconductor bridge are reduced; the current protection circuit comprises a bidirectional rectifier circuit and a detection circuit; and the NMOS is connected between the detection circuits. The application can realize ESD protection and current protection of the semiconductor bridge, prevents current from damaging the structure, and guarantees the safety of the semiconductor bridge working in an electromagnetic and ESD environment.

The application discloses a kind of generator phase-advancing capability analysis method and system based on power grid transient stability constraint, comprising the following steps: according to power grid system stability and converter station bus voltage control condition obtains single machine maximum phase-advancing depth;According to single machine maximum phase-advancing depth, obtain the phase-advancing depth of power plant and the phase-advancing depth reserved by whole plant.This application mainly aims at the problem that the regulation range of other regulating means such as shunt reactor is limited when voltage is too high due to excessive reactive power, fully considers factors such as stator end heating and power angle static stability, determines single machine maximum phase-advancing depth, considers the most serious situation of overvoltage of DC converter station, determines the phase-advancing capability of power plant and the phase-advancing capability reserved by whole plant after DC fault tripping based on whether steady-state overvoltage exceeds voltage limit, fully develops the voltage regulating capability of generator, so as to more economically and efficiently ensure the stable operation of power grid voltage.

A limiting circuit, particularly for a power supply, includes a first reverse-polarized Zener diode connected and configured to limit a voltage between two output terminals depending on a first breakdown voltage, a second reverse-polarized Zener connected and configured to limit a voltage between two output terminals depending on a second breakdown voltage, a semiconductor switch coupled in series with the second Zener diode to open or close depending on a switching signal, a first shunt resistor coupled in a load path and with the first and second Zener diodes to carry the load current and the currents flowing through the first and second Zener diodes, and a comparating device configured to generate the switching signal depending on a voltage drop over the first shunt resistor.

A computer system for controlling an energy storage system with heterogenous battery packs is provided. The system, using a processing circuitry, obtains pack-specific minimum and maximum allowed operating voltages for each battery pack; determines joint ESS-specific minimum and maximum voltage limits satisfying each of the respective pack-specific minimum and maximum allowed operating voltages for all of the battery packs; obtains actual state of charge, SoC, values for each battery pack; determine rescaled SoC values by scaling the actual SoC value for a battery pack to a range defined by an estimated SoC value of the battery pack at the ESS-specific minimum and maximum voltage limits, and controls the ESS using the rescaled SoC values for the battery packs.

Systems and methods are provided for fail-safe protection of circuitry from electrostatic discharge due through input and output connections. The power circuitry may include a string of diodes, connections to power lines, and particular diodes for voltage pull-up and pull-down clamping. There may be both a pull-up third diode in the diode string for connection between I / O and VDD and a pull-down third diode between I / O and VSS. During an ESD event the ESD device is configured to hold voltage from exceeding a threshold voltage and damaging internal circuitry. During operational mode the ESD device is turned off and does not interfere with circuit operations.

This application provides an energy storage system, including: a housing; an energy storage device housed within the housing; and a voltage limiting device, wherein a first terminal of the voltage limiting device is electrically connected to the energy storage device, and a second terminal of the voltage limiting device is electrically connected to the housing or a conductive device within the housing. This system can limit overvoltage within the energy storage device's housing while reducing the risk of thermal runaway in the energy storage system.

This invention relates to the field of distribution network fault detection technology, and is a method and system for detecting low-voltage distribution area faults based on the wide-area response of an active distribution network. The system includes a data acquisition and processing unit, which acquires signal data from the active distribution network lines and preprocesses the signal data. The acquired signal data includes voltage and current signals at the grid connection points of each distributed power source on the active distribution network lines, as well as current signals at the outgoing lines of the low-voltage distribution area. A voltage limit judgment unit determines whether more than 50% of the distributed power source grid connection points on the active distribution network lines have exceeded the voltage limit. This invention senses low-voltage distribution area faults through the wide-area response of an active distribution network containing distributed power sources, and constructs fault detection criteria through wide-area response parameters and their spatiotemporal distribution characteristics, achieving effective low-voltage distribution area fault detection and location, and improving the efficiency of fault detection.

The invention relates to the technical field of power electronics, in particular to a dual-power-supply coupling application port protection circuit suitable for series sampling of thin-film capacitors, which comprises a power supply A, a power supply B, an isolation capacitor CI, a tested capacitor Ct, a controller and a dual-power-supply coupling application port protection circuit, the dual power supply coupling application port protection circuit comprises an LR filter circuit, an air core inductor L2, a resistance-capacitance voltage division circuit, a TVS voltage limiting circuit, a double-pole-double-throw switch, an air core inductor L3, a voltage sampling circuit and a TVS voltage sampling circuit. According to the invention, a thin-film capacitor or a ceramic capacitor with low cost is adopted as a high-voltage sampling part, a hollow inductor L2 is arranged to limit the peak current of a resistance-capacitance voltage division circuit, and a TVS voltage limiting circuit is arranged to limit the peak voltage of the resistance-capacitance voltage division circuit; in addition, the air core inductor L3 is arranged to limit the peak current of the TVS voltage limiting circuit, and voltage and current protection is carried out, so that the circuit can operate reliably.

The application relates to a method for supplying power (20) to an electrolysis plant (100) with several electrolyzers (12.1, 12.2, ... 12.n) and several power converters (10.1, 10.2, ... 10.n). The electrolyzers (12.1, 12.2, ... 12.n) are connected to their respective power converters (10.1, 10.2, ... 10.n) via DC lines (DC+, DC-). The power converters (10.1, 10.2, ... 10.n) are electrically connected in parallel to each other on the AC side, in particular via a transformer (16), to an AC network (18). During operation of the electrolysis plant (100), at least one DC line (DC+, DC-) has a fixed reference to earth potential (PE), in particular by at least one DC-negative line (DC-) being connected to earth potential (PE). The procedure indicates: - Setting the respective DC currents to the electrolyzers (12.1, 12.2, ... 12.n) by the respective power converter (10.1, 10.2, ... 10.n) to supply the associated electrolyzers (12.1, 12.2, ... 12.n) depending on the respective electrolyzer setpoints (SP1, SP2, ... SPn), - Determining the current ground reference of the electrolyzers (12.1, 12.2, ... 12.n), and - Limiting the absolute values ​​of DC_minus earth voltages (MU1, MU2, ... MUn) of the DC_minus lines (DC-) relative to earth potential (PE) to a predefinable earth voltage limit value. The application also concerns a power supply (20) for an electrolysis plant (100) and an electrolysis plant (100).