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495 results about "Voltage loop" patented technology

Voltage loops Def: A loop is any continuous path (that may even cross gaps across open space) that ends where it starts. Note: The goal of writing current summation and voltage loop equations is to obtain n equations in n unknowns that we can solve to find all the currents and voltages in a circuit.

Network construction type converter, fault ride-through control method and system thereof, terminal and medium

The invention provides a fault ride-through control method and a fault ride-through control system for a grid-forming converter, which are characterized in that the current of the grid-forming converter under an asymmetric fault is controlled by adopting a negative-sequence current reference generation strategy aiming at an inner ring of a controller, and negative-sequence reactive current is injected into a power grid; adopting a partial sequence current amplitude limiting strategy to control the maximum phase current amplitude of the injected asymmetric current not to exceed an amplitude limiting value; controlling the boundary of an active reference value by adopting an active reference value amplitude limiting strategy for an active synchronization ring; a synchronous damping link is adopted to enhance damping in power angle swing; for a reactive voltage loop, a reactive voltage variable coefficient control strategy is adopted to control the output of the maximum reactive current; and an internal potential locking strategy is adopted to suppress overvoltage. According to the invention, negative-sequence reactive power is provided, and overcurrent of each phase is avoided; the power angle characteristic is improved, and the transient stability is improved; stable transient voltage support is provided in a current output capability range; and after the fault is recovered, the voltage of the converter grid-connected point is smoothly recovered.
Owner:SHANGHAI JIAOTONG UNIV +3

Off-grid multi-machine parallel control method for energy storage converter

The invention provides an off-grid multi-machine parallel control method for an energy storage converter, and the method comprises the following steps: a host obtains a given voltage, and transmits the given voltage to each slave; the host acquires power feedback of each slave, calculates average power based on the power feedback of all the slaves, and sends the average power to each slave; the slave obtains slave first voltage compensation based on the average power and the power feedback; and the slave performs voltage loop control and current loop feed-forward calculation at least based on the given voltage and the slave first voltage compensation. According to the energy storage converter off-grid multi-machine parallel control method provided by the invention, the host issues the average power to each slave to realize power equalization, and the voltage compensation is calculated according to the difference between the average power and the power feedback to compensate to the given voltage; the dynamic responsiveness of the dynamic voltage is improved, meanwhile, the power and current balance of each energy storage converter in parallel operation is guaranteed, and dynamic and steady-state operation of multiple energy storage converters in parallel operation is achieved.
Owner:ZHEJIANG JINKO ENERGY STORAGE CO LTD

Power decoupling method for cooperative control of voltage feed-forward compensation and adaptive virtual impedance

The invention relates to the technical field of new energy power system control, and relates to a power decoupling method for cooperative control of voltage feed-forward compensation and adaptive virtual impedance. The method comprises the following steps: acquiring a power grid current and a power grid voltage, and calculating a reactive power measured value and an active power measured value of a power grid; virtual synchronous machine control is carried out, and a voltage feed-forward pre-compensation item is introduced into a reactive power control loop; calculating a reactive power control loop after VSG compensation, and obtaining VSG output side voltage and instantaneous angular frequency; self-adaptive virtual impedance control is adopted, a self-adaptive virtual impedance reference value is calculated, line impedance is dynamically adjusted, and a voltage loop input instruction voltage is calculated according to the line impedance; and adjusting the output performance of the inverter according to the instruction voltage. According to the invention, the problem of power fluctuation caused by VSG output voltage amplitude variation is effectively solved, and the dynamic influence of a power coupling item is weakened.
Owner:SHANDONG UNIV

High-precision current limiting circuit of LDO with NMOS tube as power tube

The invention provides a high-precision current limiting circuit of an LDO (Low Dropout Regulator) with an NMOS (N-channel Metal Oxide Semiconductor) tube as a power tube, which is applied to the technical field of current limiting circuits and comprises a voltage loop and a current loop, and the voltage loop is used for monitoring and stabilizing the output voltage VOUT of a power tube NM1; and the current loop is used for acquiring a sampling current according to the load current of the power tube NM1, comparing the sampling current with a reference current IREF, and when the sampling current is higher than the reference current IREF, driving and controlling the output voltage VOUT of the power tube NM1 to be reduced so as to limit the load current of the power tube NM1 to continue to rise. When the LDO works normally, the output voltage VOUT of the power tube NM1 is stabilized through the voltage loop, and when the load current is too high, the output voltage VOUT of the power tube NM1 is driven and controlled to be reduced through the current loop, so that the load current of the power tube NM1 is prevented from continuing to rise, and the stability and the safety of the LDO are improved.
Owner:NANJING MICRO ONE ELECTRONICS

Control method for preventing current backflow in mppt charging based on Buck-Boost circuit

The invention discloses a buck-boost circuit-based mppt charging current backflow prevention control method, and relates to the technical field of switching power supplies, and the method comprises the steps: collecting a photovoltaic input voltage, a battery output voltage, and an inductive current flowing through an inductor; the current input power is calculated based on the photovoltaic input voltage and the inductive current, and the reference voltage is dynamically adjusted through an MPPT loop algorithm; pI voltage loop operation is carried out on the output voltage and the adjusted reference voltage, and expected charging current is generated; pI current loop operation is carried out on the expected charging current and the inductive current sampling value after proportionality coefficient adjustment, and a PWM duty ratio control signal is output to adjust the driving states of the four switching tubes; when the judgment circuit is in an intermittent conduction mode and meets critical conditions, a driving signal of the fourth switching tube is shielded, and only a body diode realizes a current path to prevent reverse flow of current; the battery current is effectively prevented from flowing backwards, and the system safety and the energy utilization efficiency are improved.
Owner:GUANGZHOU ALLPOWERS IND INT

VSG damping enhancement control method based on active lead-lag compensation

The invention discloses a VSG damping enhancement control method based on active lead-lag compensation, and belongs to the field of new energy converter technology control. The method comprises the steps of firstly sampling output voltage and current of a new energy converter, calculating output instantaneous active power and reactive power of a virtual synchronous generator through the sampled voltage and current, and then obtaining an output phase instruction value and a voltage control instruction value through an optimized active-frequency loop and an optimized reactive-voltage loop; and finally, through voltage and current double-closed-loop control, the control of the new energy converter is realized. According to the method, the system damping ratio is increased in the transient process through the control method that the active power is fed back to the forward channel after lead-lag compensation, overshoot and oscillation generated when the active power output by the system changes are effectively restrained, tiny overshoot which cannot be restrained cannot be generated, and when the power grid angular frequency breaks away from the rated value, the system damping ratio is increased. And the steady-state characteristics of the system are not influenced.
Owner:HEFEI UNIV

General networking control method for converter

The invention relates to a general network construction control method for a converter, the converter is connected to a common connection point through an LCL filter, the control link comprises an active outer ring, a reactive outer ring, a virtual impedance ring and a voltage and current control ring, and in the reactive voltage control link, a voltage amplitude difference value and a reactive power difference value are obtained through calculation; multiplying and superposing with a voltage feedback coefficient and a reactive power regulation coefficient, and generating a voltage amplitude reference of a converter voltage loop through a proportional-integral regulator; in the active frequency control link, a frequency difference value and an active power difference value are obtained through calculation, are multiplied by a frequency feedback coefficient and an active adjustment coefficient respectively and then are superposed, and a frequency reference of a voltage inner loop is generated through a proportional-integral regulator; in the general networking control process, outer loop control parameters are changed according to different application scenes, and different active loop and reactive loop control is achieved.
Owner:TIANJIN UNIV

Broadband self-adaptive impedance remodeling method based on energy storage

The invention provides a broadband self-adaptive impedance remodeling method based on energy storage, which comprises the following steps of: dividing an impedance frequency band of an energy storage system according to analysis on a PLL (Phase Locked Loop), a voltage loop, a current loop and a filter, and constructing an improved self-adaptive impedance remodeling control strategy based on combination of active damping and virtual admittance based on the divided frequency band; according to the impedance remodeling control strategy, establishing an energy storage inverter system impedance model considering impedance remodeling; based on an impedance model, the frequency band overlapping effect between different frequency bands and between different control links is comprehensively considered, and the impedance near a system oscillation frequency point is remodeled through sequential optimization design of PLL control, virtual admittance control and active damping control. The purposes of broadband oscillation suppression of the diversified new energy cluster sending-out system and safe and stable operation of a power system are achieved.
Owner:STATE GRID GANSU ELECTRIC POWER RESEARCH INSTITUTE +1

Network source coordination control system and method of offshore wind power flexible direct current power transmission system

The invention provides a network source coordination control system and method for an offshore wind power flexible direct current transmission system, and the system comprises a receiving end converter control module which controls the output frequency of a receiving end converter through a power ring by simulating the synchronous operation mechanism of a virtual synchronous generator; the voltage loop controls the output voltage of the receiving end converter; the current reference value of the current loop is output and given through the voltage loop, and current tracking is realized through PI control; the sending-end converter control module is used for reflecting the active demand information of the system on the frequency of the sending-end offshore wind power collection alternating-current system to realize active support control of the offshore wind turbine generator to the flexible direct-current power transmission system; and the offshore wind turbine generator control module is used for participating in system frequency modulation control through the wind turbine generator when the wind turbine generator runs in a deloading mode under the normal condition and the power is unbalanced based on the variable-speed wind turbine generator control strategy.
Owner:SHANDONG ELECTRIC POWER ENG CONSULTING INST CORP

Fault voltage ride-through optimization method and system for network construction type energy storage converter

The invention belongs to the technical field of new energy, and particularly relates to a fault voltage ride-through optimization method and system for a network construction type energy storage converter. Carrying out positive and negative sequence separation and Clark-Park coordinate transformation on the three-phase power grid voltage and the inversion current, calculating active power and reactive power of the network-forming type energy storage converter, and carrying out power loop control to obtain three-phase reference voltage and angular velocity; performing voltage loop control, and dynamically adjusting a positive sequence active current and a positive sequence reactive current according to whether a low-voltage-crossing indication signal exists or not; performing positive-sequence current loop control and negative-sequence current loop control, and then performing inverse Clark-park conversion to obtain positive-sequence three-phase reference voltage and negative-sequence three-phase reference voltage; and superposing the positive-sequence three-phase reference voltage and the negative-sequence three-phase reference voltage for PWM (Pulse Width Modulation). According to the invention, when the power grid voltage is unbalanced due to a fault, the oscillation of the direct current side voltage and power caused by the negative sequence component is eliminated, and the power angle stability is improved and the fault current is suppressed by dynamically adjusting the related reference value during the fault voltage ride-through period.
Owner:HKUST DIGITAL (SHANGHAI) ENERGY TECH CO LTD

Control system for phase-locked loop-free synchronous tracking mode of hybrid network following-constructing system

PendingCN119482691Asmall fluctuation rangeImprove steady state performanceSingle network parallel feeding arrangementsVirtual synchronous generatorTransient state
The invention discloses a control system for a phase-locked loop-free synchronous tracking mode of a hybrid network following-construction system, and belongs to the technical field of virtual synchronous generator control, phase angle information generated by network construction type control is used for synchronization of a network following type inverter, and synchronization of the network following type inverter is realized without a phase-locked loop. According to the control technology, potential unstable factors caused by the dynamic state of the phase-locked loop can be avoided, and meanwhile, the two inverters of the following network and the constructing network have better transient performance. According to the improved scheme, an ideal voltage source on the direct current side of the inverter is replaced by a boost circuit controlled by a single current loop, and a direct current voltage loop is added to an active loop controlled by a network constructed on the alternating current side. Compared with the control technology provided by the invention, the improvement enables the control technology to have no frequency steady-state deviation and have better transient and steady-state performance.
Owner:HEFEI UNIV OF TECH +1

Direct-current transformer power self-balancing control system

The invention discloses a direct-current transformer power self-balancing control system, which belongs to the technical field of direct-current self-energy taking under a direct-current power distribution network, and comprises a plurality of flyback converters, and a master-slave control framework is formed by taking the actually grounded flyback converter as a master module and taking other flyback converters as slave modules; the main module controls an MOS tube in the main module to be switched on or switched off according to the reference duty ratio; and the slave module controls on or off of an MOS tube in the slave module according to the reference duty ratio and the duty ratio correction. The master module adopts a system output voltage loop to maintain the stability of the system output voltage, the slave module input stage adopts an input grading ring to realize the sharing of the input voltage between flyback modules, and the slave module output stage adopts an output current sharing ring to improve the dynamic response effect of the system. The system can solve the problem of power distribution imbalance caused by inconsistent parameters between flyback modules.
Owner:STATE GRID JIANGSU ELECTRIC POWER CO LTD RESEARCH INSTITUTE +3

Network construction control method and system of static var generator without super capacitor

The invention provides a network construction control method and system for a static var generator without a super capacitor, and the method comprises the steps: obtaining a variable needed by the control of the static var generator, comprise a three-phase bridge arm voltage measurement value, a three-phase bridge arm voltage instruction value, a reactive power instruction value, an alternating voltage amplitude instruction value, an output reactive power measurement value, an output alternating current measurement value, an alternating voltage amplitude measurement value of a common coupling point, a direct-axis voltage measurement value and a quadrature-axis voltage measurement value; obtaining a three-phase modulation voltage through a voltage loop and an alternating current loop according to variables required by control and based on direct current voltage-frequency-phase control and reactive power-voltage droop control; and obtaining a switch tube control signal according to the three-phase modulation voltage, and completing network construction control of the static var generator according to the switch tube control signal. According to the invention, the stability of the DC voltage of the static var generator can be ensured without adding a super capacitor, and active support is provided for an AC side power grid.
Owner:ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID JIBEI ELECTRIC POWER CO LTD +1

Low-voltage ride-through control method and device for network-forming inverter

The invention relates to the technical field of power electronics, and discloses a low-voltage ride-through control method and device for a network-forming inverter, and the method comprises the steps: monitoring the voltage drop degree of a network side; and adjusting a proportional control coefficient and an integral control coefficient of a proportional-integral controller in the grid-forming inverter according to the grid-side voltage drop degree. By adaptively adjusting the reactive power-voltage loop PI parameter, the stability of the inverter is ensured, and the reactive current response speed of the network-forming inverter during low voltage ride through is greatly improved at the same time.
Owner:GOODWE TECHNOLOGIES CO LTD

Power supply device and test machine

The utility model relates to a power supply device and a testing machine, the power supply device comprises a main loop, a voltage loop, a current loop and a clamping circuit, in a pressurization mode, when a detection current output by the clamping circuit at the current loop is in a set current clamping range, the output impedance is high resistance; and when the detection current output by the current loop is not in a set current clamping range, the clamping circuit triggers the clamping current to carry out analog output, and the output impedance is switched to low resistance, so that the output of the main loop is equivalent to a constant current source. In the current adding mode, when the detection voltage output by the clamping circuit at the voltage loop is within a set voltage clamping range, the output impedance is high resistance; and when the detection voltage output by the voltage loop is not in a set voltage clamping range, the clamping circuit triggers the clamping voltage to perform analog output, and the output impedance is switched to low resistance, so that the output of the main loop is equivalent to a constant voltage source. The simulation regulation function is achieved, and the response speed is high.
Owner:HANGZHOU CHANGCHUAN TECH CO LTD

Controller, control device and switching power supply

The invention discloses a control method, a control device and a switching power supply, the control method is applied to an N-phase converter, and the control method comprises the following steps: calculating an electrical parameter output by the N-phase converter and a modulation wave required by each phase bridge arm switching tube when a common-mode voltage reaches an expected value through voltage loop and current loop double closed-loop control; adjusting the current modulation wave of each phase of bridge arm switch tube so as to obtain N first modulation waves; calculating a second frequency required by a modulation wave of each phase of bridge arm switch tube when each phase of bridge arm switch tube realizes ZVS by predicting the magnitude of bridge arm side inductive current pulsation in each phase of LCL filter, taking the second frequency as the frequency of a carrier wave, and generating N carrier waves; and comparing the first modulation wave of each phase of bridge arm switch tube with the corresponding carrier wave to obtain a driving signal for controlling the on and off of each phase of bridge arm switch tube. According to the invention, good harmonic performance can be obtained while low common-mode voltage is realized.
Owner:MORNSUN GUANGZHOU SCI & TECH

Resistance-capacitance circuit constant current precision control method

The invention discloses a resistance-capacitance circuit constant current precision control method, and relates to the technical field of resistance-capacitance circuits, and the method specifically comprises the steps: S1, constructing a resistance-capacitance circuit topology, and building a small signal model based on the resistance-capacitance circuit topology; s2, double-closed-loop control of an outer current loop and an inner voltage loop is adopted, a reference voltage signal is generated in the outer current loop through a PI controller, and current tracking is achieved in the inner voltage loop based on a nonlinear algorithm; and S3, introducing a dynamic compensation mechanism, and adaptively inhibiting a precision error through feed-forward compensation and parameters. According to the invention, double closed-loop control of outer loop current and inner loop voltage is adopted, and dynamic compensation is carried out on current errors through feed-forward compensation and parameter self-adaption. And the constant current precision control of the multi-branch resistance-capacitance circuit is realized by precisely calculating the duty ratio and performing closed-loop correction.
Owner:SHENZHEN ZHI YUE SHENG ELECTRONIC TECH CO LTD

Stability analysis method and system of tracking and networking inverter hybrid system, and medium

The invention provides a stability analysis method and system for a tracking and networking inverter hybrid system and a medium, and the method comprises the steps: selecting the active power of a tracking inverter and the reactive power of a networking inverter as core variables through working condition variable dimensionality reduction; determining a working condition range in combination with capacity constraint, performing discretization processing, and calculating dq components of voltage and current of an inverter port based on a discrete working condition; discrete impedance models of the two types of inverters are respectively constructed; the influence of a phase-locked loop controller, a current loop controller and a power loop controller is considered in a following network type, and the effect of a virtual synchronous controller, a current loop controller and a voltage loop controller is included in a construction network type; and calculating a closed-loop transfer admittance matrix of the power grid through the discretized impedance of the inverter to realize stability analysis of the hybrid system. According to the method, the modeling complexity is effectively reduced, the stable working areas of the system under different working conditions can be quantified, and an accurate reference basis is provided for stable operation of the hybrid inverter system.
Owner:STATE GRID HUBEI ELECTRIC POWER RES INST

Multi-phase BUCK converter and high-dynamic adaptive phase cutting method

The invention discloses a multiphase BUCK converter and a high-dynamic self-adaptive phase cutting method. The multiphase BUCK converter comprises a 16-phase power level, a current sampling module, an MOS driving module, a digital control module, a CMCOT simulation main control loop and a dynamic detection circuit. The MOS driving module controls a switching tube in the 16-phase power level, the current sampling module collects an inductive current signal, the input end of the CMCOT simulation main control loop is connected with the output end of the current sampling module, and a PWM control signal is output to the digital control module; the input end of the dynamic detection circuit is connected with an output signal of a voltage loop gain in the CMCOT analog main control loop, and a mark signal is generated and output to the digital control module; the digital control module generates a phase cutting signal. A phase cutting strategy is correspondingly provided, the number of PWM started by a phase cutting signal is adaptively changed, the transient voltage undershoot is reduced, meanwhile, voltage overregulation is avoided, and the transient performance is remarkably improved.
Owner:SOUTHEAST UNIV

Network construction type converter control method and system suitable for multiple power grid intensities

The invention provides a network construction type converter control method suitable for multiple power grid intensities, and belongs to the field of new energy grid-connected stability. The method comprises the steps that the actual output power of an inverter is calculated according to inverter side capacitor voltage and grid-connected current; the actual output power of the inverter and the power reference value control an output internal potential amplitude reference value and an internal potential phase angle through the virtual synchronous generator; subtracting the voltage drop of the grid-connected current on the virtual impedance from the internal potential amplitude reference value to obtain a virtual internal potential; inputting the virtual internal potential as a reference voltage into a voltage and current double-loop controller, inputting a grid-connected current into a proportional differential controller, subtracting the output of the proportional differential controller from the output of the voltage and current double-loop controller, inputting an obtained result into an inverter through an SPWM modulator, and controlling the inverter; the invention also provides a control system of the network-forming converter. Grid-connected current proportional differential feedback is introduced, the inner loop control bandwidth is kept constant in the dynamic change process of the power grid strength, and power-voltage loop harmful coupling is eliminated.
Owner:STATE GRID ANHUI ELECTRIC POWER CO LTD ELECTRIC POWER SCI RES INST +1

Optimal Hankel norm approximation-based grid construction converter model order reduction method, system, equipment and medium

The invention belongs to the technical field of mathematical modeling of a network construction converter, and discloses a network construction converter model order reduction method, system and equipment based on optimal Hankel norm approximation and a medium, so as to solve the problem of applicability of a network construction converter model under the condition of a high short circuit ratio. The method is based on a full-order model and comprises the steps of S1, current loop order reduction processing, S2, voltage loop Hankel approximation order reduction and S3, construction of a nine-order model. According to the method, through dq decoupling, feedforward offset and optimal Hankel norm approximation, a full-order system is reduced into a nine-order model, and the calculation complexity is greatly reduced while the control precision is ensured. According to the method, active and reactive high-frequency component quantity links filtered by a filter and a line resistance-inductance equation are considered, the nine-order model of the network construction converter is constructed, and the model precision is effectively improved.
Owner:ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY

Control method and system for small-duty-ratio BOOST module based on digital control

The invention relates to the technical field of switching power supply analog control, in particular to a control method and system for a small-duty-ratio BOOST module based on digital control, and the method comprises the following steps: S1, carrying out the sampling of the equal-proportion reduced output voltage of an operational amplifier through an ADC analog-to-digital converter, processing the sampled voltage value through a filtering algorithm to obtain an output voltage VO; and S2, carrying out calculation processing on the output voltage VO through a PID control algorithm, and obtaining an expected output voltage through a fixed-frequency adjustment duty ratio PWM and a fixed-duty ratio frequency modulation PFM. Efficient and stable voltage boosting is achieved through double-closed-loop digital control, dynamic response and anti-interference capacity are achieved, the core lies in collaborative design of power conversion and a control strategy, input direct-current voltage is boosted to higher stable output voltage, a double-closed-loop (voltage loop + current loop) control strategy is adopted, and the voltage boosting effect is achieved. And closed-loop adjustment is realized by combining PWM driving and ADC sampling.
Owner:TIANSHUI 749 ELECTRONICS

Voltage conversion circuit compatible with buck and boost and switching power supply conversion chip

The embodiment of the invention provides a voltage conversion circuit compatible with step-down and step-up and a switching power supply conversion chip, and the circuit comprises a main circuit which is configured to receive an input voltage and adjust an output voltage through the charging and discharging control of an inductor coupled with the input voltage; a mode control circuit configured to output a first voltage signal or a second voltage signal according to a magnitude relationship between the input voltage and the output voltage; the first transistor is coupled between the main circuit and the output voltage and is configured to control the grid voltage of the first transistor by the voltage signal output by the mode control circuit; the voltage loop control circuit is configured to generate control signals for controlling switches of a first power tube and a second power tube in the main circuit according to feedback of the output voltage and the reference voltage; and the protection circuit is configured to protect the first power tube. The problems that a large surge current passes through from input to output after an existing BOOST type circuit is powered on, the voltage obtained during compatible voltage reduction is inverted, and the soft start process of voltage boosting is not smooth are solved.
Owner:SILICON CONTENT TECH CO LTD

Method and device for measuring resistance value of contact resistor of crimping tube and test loop for measuring resistance value of contact resistor of crimping tube

The invention discloses a method and device for measuring the resistance value of a crimping tube contact resistor and a test loop for measuring the resistance value of the crimping tube contact resistor, and belongs to the field of cables. The method comprises the following steps: acquiring the total number of crimping pipes in a test loop, the first length of a reference cable, the reference temperature of a conductor in the reference cable and the total length of the cable except the length of the crimping pipes in the test loop; when the power frequency current enters the test loop and the real-time temperature of the reference cable reaches the reference temperature, acquiring the loop voltage and loop current of the test loop and the voltages at the two ends of the reference cable; according to the loop voltage, the loop current, the two-end voltage, the first length and the total length of the cable, the total contact resistance value of the test loop is calculated; and determining the contact resistance value of each crimping tube in the test loop according to the total number of the crimping tubes and the total contact resistance value. By implementing the application, the problem that the contact resistance cannot be effectively measured in the prior art can be solved.
Owner:GUANGZHOU POWER SUPPLY BUREAU GUANGDONG POWER GRID CO LTD

Automatic current sharing control method for interleaved parallel BUCK converter

An automatic current sharing control method for an interleaved BUCK converter belongs to the technical field of power electronics, and comprises the following steps: step S1, obtaining an output voltage and a given output voltage of a load end of the interleaved BUCK converter; obtaining the current of each phase of inductor; s2, obtaining an average value of the inductive current of each phase, and averaging the average value of the inductive current of each phase as a reference value of a current loop; s3, calculating a duty ratio signal through a current loop; s4, calculating a duty ratio signal through a voltage loop; and S5, superposing the duty ratio signal of the current loop operation of each phase with the duty ratio signal of the voltage loop operation. According to the invention, the inductive current of each phase follows the average inductive current of three phases in real time, high-precision current-sharing control is realized, and the control reliability is improved, so that the output current is controlled at an average level.
Owner:SHENYANG INST OF ENG

Nonlinear robust control method and device for DC-DC converter

The invention belongs to the technical field of power electronics, and provides a nonlinear robust control method and device for a DC-DC converter. The method comprises the following steps: acquiring an output voltage of the DC-DC converter and feeding back the output voltage to a terminal sliding mode controller, calculating a voltage error between a reference voltage and the output voltage of the DC-DC converter by the terminal sliding mode controller, and calculating the voltage error of the DC-DC converter according to a relation among a preset fractional order nonlinear sliding mode surface, a linear sliding mode surface and the voltage error, generating a first control signal as a reference current of the linear controller to form a voltage loop; and the output current of the DC-DC converter is obtained and fed back to the linear controller, the linear controller generates a second control signal in combination with the reference current and acts on a set power switch tube of the DC-DC converter to form a current loop, and finally DC-DC converter double-loop nonlinear robust control based on cooperation of the reference voltage, the output voltage and the output current is achieved. And good transient response is ensured.
Owner:SHANDONG UNIV

Power current loop control method for seamless switching of grid-connected and off-grid modes of energy storage PCS

The invention discloses a power current loop control method for seamless switching of grid-connected and off-grid modes of an energy storage PCS, and the method achieves the seamless switching of the two control modes through the dynamic adjustment of a power reference value of an inverter, the merging of a PQ-controlled current loop and a Vf-controlled current loop, and the introduction of a PQ-controlled reference current into a Vf control loop. The method specifically comprises the following steps: detecting voltage, current and phase parameters in grid-connected and off-grid states, and calculating corresponding power; when the switching signal is received, the grid-connected active power is adjusted to an off-grid preset value through a PI controller; switching an inverter control mode within a power error allowable range, and introducing a PQ reference current to a Vf voltage loop; and control mode switching and switch state change are completed in sequence. According to the method, the problems of voltage fluctuation and current sudden change during switching in a traditional method are effectively solved, bidirectional seamless switching can be realized without reducing zero output power, dependence on an additional energy storage system is reduced, and the operation stability of the micro-grid is improved.
Owner:HANGZHOU ELECTRIC EQUIP MFG +1

Fault current calculation method and system for high-voltage alternating-current submarine cable grounding system and storage medium

The invention discloses a fault current calculation method and system for a high-voltage alternating-current submarine cable grounding system and a storage medium, and the method comprises the following steps: enabling a power supply device and an electric device to be equivalent to an impedance and series voltage source combination and a load impedance based on the Thevenin equivalence theorem; in combination with the double-end grounding characteristic, a submarine cable loop is equivalent according to a pi type, and a three-phase equivalent circuit is constructed; determining a fault phase, and dividing the submarine cable as a left side and a right side by a fault point; a voltage loop equation is listed based on the Kirchhoff theorem, and a matrix recursion rule is deduced in combination with a double-side elimination principle. And establishing an analytic relationship between the main sections of the submarine cables at the power side and the short-circuit side and the fault circulating current according to a recursion rule. And with a fault point current equation as a boundary condition, left sheath fault circulation distribution is solved simultaneously. And repeating the steps on the right side to obtain right side distribution so as to obtain fault phase whole-line distribution. According to the method, the circulation distribution can be accurately calculated, the fault analysis accuracy and efficiency are improved, and support is provided for submarine cable operation and maintenance and the like.
Owner:ZHEJIANG UNIV

Current sharing control method and device for charging module parallel operation system

The invention provides a current-sharing control method and a current-sharing control device for a charging module parallel system, which can simplify software and hardware design of the system and realize current-sharing control in a simpler and more reliable way, and the charging module parallel system comprises a plurality of charging modules which are connected in parallel. Comprising the following steps: detecting whether the charging module parallel operation system meets the condition that at least two charging modules are started or not; if yes, detecting whether a current sharing starting condition is met, and if yes, starting current sharing; otherwise, current sharing is not started; obtaining the number of charging modules needing current sharing and current sharing adjustment data of the charging modules, and generating an adjustment quantity to modify a reference control voltage in combination with the current sharing adjustment data and the number of the charging modules needing current sharing; and in combination with the current-sharing regulation data and the number of the charging modules needing current sharing, generating a regulation variable to modify a given voltage value of the voltage loop, and realizing current sharing by modifying the reference control voltage and the given voltage value of the voltage loop at the same time.
Owner:SUZHOU XINYUAN ELECTRONIC TECH CO LTD

Consistency stable operation control method for net-forming type flywheel energy storage array

The invention provides a consistent and stable operation control method for a net-forming type flywheel energy storage array, and relates to the technical field of flywheel energy storage. Comprising a distributed power distribution strategy based on a ratio consistency algorithm and a flywheel energy storage array control strategy based on'voltage-rotating speed-current 'three closed loops. For rotating speed control, the problems of energy-saving voltage stabilization, SOC management, flywheel unit rotating speed balance and the like do not need to be considered, only the rotating speed loop needs to be connected between the voltage loop and the current loop in series, and the structure is simpler. In terms of power distribution, the strategy does not depend on a central controller or a leader unit, each flywheel unit only needs to exchange information with the adjacent unit to complete power distribution, the reliability of the flywheel energy storage array is improved, and the robustness is good.
Owner:STATE GRID LIAONING ELECTRIC POWER CO LTD +1