19 results about "Current compensation" patented technology

This application discloses a method, device, and medium for setting the zero-sequence current compensation coefficient in a mixed cable line, belonging to the field of relay protection technology for mixed transmission lines. It includes: obtaining the power frequency impedance and length parameters of an N-segment mixed cable line; and obtaining the comprehensive zero-sequence current compensation coefficient K at each connection point of the N-segment mixed cable line. i 1≤i≤N and i is an integer; obtain the comprehensive zero-sequence compensation coefficient K of the fault point. ’ j 1≤j≤N and j is an integer; obtain the comprehensive zero-sequence current compensation coefficient K0 at the end of the operating range of the grounding distance I protection; determine K ’ j The monotonicity of K0; based on monotonicity, compare K0 with N K's. i The value of the zero-sequence current compensation coefficient K is obtained by considering the magnitude of the zero-sequence current compensation coefficient; N≥2 and N is an integer. This application improves the accuracy of the zero-sequence current compensation coefficient setting, which can ensure the reliability of the grounding distance I-stage protection operation and avoid overshooting and false operation when there is a fault at the end of a mixed line.

The invention discloses a motor heating method and device, and a frequency converter. The method comprises the steps of determining an initial current instruction, and performing adjustment amplitude limiting and current compensation processing on the initial current instruction based on a voltage utilization rate to obtain a rotation current angular frequency and a compensation current instruction; a target axis given current instruction is determined based on the given heating power, and a target axis current instruction is obtained based on the target axis given current instruction and the compensation current instruction; acquiring a voltage vector compensation angle and a current vector angle based on the rotating current angular frequency, and acquiring a voltage vector angle based on the voltage vector compensation angle and the current vector angle; and inputting the target shaft current instruction and the voltage vector angle to a preset current controller, so that an inverter outputs high-frequency alternating current to a motor to heat the motor. The power control precision and the control robustness are improved, the dynamic control with a wider heating power range can be realized, and excessive computing resources are not needed.

The invention discloses an electric energy quality control module function demand control method and device and a storage medium, and belongs to the technical field of electric energy quality control. Performing current distribution according to the load side reactive current vacancy demand, the harmonic current vacancy demand and the unbalanced current vacancy demand of the current demand period, and obtaining a function demand parameter of the next slip frequency period according to the distributed current and the total current vacancy demand; and under the constraint of the functional compensation current component upper limit, performing functional current compensation on the load in the power grid based on the reactive current vacancy demand, the harmonic current vacancy demand and the unbalanced current vacancy demand on the load side. The technical problems that an existing electric energy quality treatment scheme cannot completely adapt to the actual electric energy quality treatment requirement, and when the actual requirement does not conform to the capacity configuration of all the functions, the number of all the function modules can only be adjusted through power failure again can be solved.

A current inner loop reference current value compensation method, a control method, a system and a medium are applied to a PI control process of a DC converter, and the method comprises the following steps: according to a power frequency ripple oscillation condition at a bus voltage and a first bus deviation value at a current moment, determining whether PI control at the current moment satisfies a current inner loop reference current value compensation condition; when a compensation condition is met, determining a current compensation value according to the second bus deviation value at the current moment; wherein the first bus deviation value is an absolute difference value between a preset reference voltage value and a filtering result of the bus voltage sampling value through the first filter, and the second bus deviation value is an absolute difference value between the preset reference voltage value and a filtering result of the bus voltage sampling value through the second filter; the first filter and the second filter are both first-order RC filters, the filter coefficient of the first filter is larger than that of the second filter, and stable operation of PI control is guaranteed under the extreme heavy load transient working condition.

This invention provides a multi-dimensional method and system for assessing damage to DC contactors in charging piles. The method includes: a host acquiring the current current value, current temperature, and previous temperature during the charging process of the DC contactor, as well as the voltage sequence and / or current sequence during the previous disconnection process, and historical charging and disconnection data; obtaining a disconnection damage score based on the voltage transient characteristics of the voltage sequence and / or the current drop characteristics of the current sequence; obtaining the current drift degree based on the difference between the current current value and the current compensation current value; obtaining the temperature rise rate deviation of the contact resistance based on the deviation between the actual temperature rise rate and the expected temperature rise rate; the actual temperature rise rate is obtained from the current temperature and the previous temperature, and the expected temperature rise rate is obtained based on the compensation current value and a preset temperature rise model; analyzing historical charging and disconnection data to obtain cumulative operating load data; and comprehensively analyzing the above four indicators to assess the damage status of the DC contactor.

A current inner loop reference current value compensation method, control method, system and medium are applied to the PI control process of a DC converter. The method comprises: determining whether the PI control at the current moment satisfies the current inner loop reference current value compensation condition according to the power frequency ripple oscillation condition at the bus voltage and the first bus deviation value at the current moment; when the compensation condition is satisfied, determining the current compensation value according to the second bus deviation value at the current moment; wherein the first bus deviation value is the absolute difference between the preset reference voltage value and the filtering result of the bus voltage sampling value through a first filter, and the second bus deviation value is the absolute difference between the preset reference voltage value and the filtering result of the bus voltage sampling value through a second filter; the first filter and the second filter are both first-order RC filters, and the filtering coefficient of the first filter is greater than the filtering coefficient of the second filter, thereby ensuring stable operation of the PI control under extreme overload transient conditions.

The sampling current compensation method based on the extended state observer solves the problem that the current sampling compensation method based on the current loop has a small application range and is limited by the number and position of current sensors, and belongs to the field of motor driving.The application comprises the following steps: obtaining sampling current i dm 、 qm 、 z1m 、 z2m , sampling voltage u d 、 u q 、 u z1 、 u z2 , u d 、 u q 、 u z1 、 u z2 、 i dm 、 i qm 、 i z1m 、 i z2m , and error current i de 、 i qe , obtained by current observation are input into an extended state observer to obtain an estimated value, the extended state observer comprises a d-q plane extended state observer and a z1-z2 plane extended state observer; error current i de 、 i qe 、 i z1e 、 i z2e , is obtained according to the estimated value; and the error current obtained is subtracted from the sampling current in the rotating coordinate system to realize error compensation of the sampling current.The compensation method of the application is independent of the number and position of current sensors and has a wide application range.

The application discloses a photovoltaic sending-out line pilot protection method and system based on a Dice waveform similarity, and belongs to the technical field of line pilot protection. The method comprises the following steps: selecting the sampling data window length on both sides of the photovoltaic sending-out line, and continuously sampling the voltage and current on both sides of the line; calculating the Dice similarity of the sampling current of each phase on both sides of the line after transient capacitance current compensation according to the voltage and current sampling values on both sides of the line, wherein the Dice similarity criterion is 1 if the Dice similarity is greater than the setting value, and the Dice similarity criterion is 0 otherwise; and sending the corresponding phase tripping signal according to the Dice similarity criterion, wherein the corresponding phase protection tripping signal is sent if the Dice similarity criterion is 1, and the corresponding phase protection tripping signal is not sent if the Dice similarity criterion is 0, so that the photovoltaic sending-out line pilot protection can correctly act in the internal fault and external fault of the 500kV line. Through the application, the problem of the sensitivity reduction of the photovoltaic sending-out line differential protection can be effectively solved under various transition resistance short-circuit faults and other complex conditions at various positions of the line, and the application has the characteristics of simplicity, reliability, easy operation and strong applicability.

The invention relates to the technical field of motor control, and discloses a linear motor system motor cogging force compensation method, device, equipment and medium, and the method comprises the following steps: determining acceleration and deceleration segment displacement according to speed and acceleration, and expecting to carry out n motor pitch sampling so as to obtain total motion displacement Moveis and Movedisgt; the sum of n motor pitches and acceleration and deceleration section displacements; selecting a constant speed section electrical angle according to the acceleration section displacement and the initial position electrical angle, moving along the same direction at equal interval angles, and recording a position where an electrical angle compensation value can be obtained; counting the Q-axis current absolute value corresponding to the position where the electrical angle compensation value can be obtained, and obtaining the current compensation value of the motor cogging force; and performing feed-forward current compensation on the current compensation value. According to the scheme, feedforward compensation is carried out based on the current value corresponding to the electrical angle, the current is given in advance to actively suppress the influence of cogging force fluctuation, and the speed error and the position error of the constant speed section in the motion of the linear motor can be effectively reduced.

The invention provides a non-full-line parallel line grounding distance protection method for coupling zero sequence current compensation, and relates to the technical field of relay protection, and the method comprises the steps: collecting the three-phase voltage and three-phase current of a protected line in real time, and judging the operation mode of the line; calculating a fault distance based on different operation modes, constructing a segmented zero-sequence network fault coupling equation based on a mutual inductance difference between a parallel segment and a non-parallel segment, and solving the segmented zero-sequence network coupling equation to obtain a coupling zero-sequence current; the fault distance is compared with the length of the parallel section to judge that the fault is located in the parallel section, the junction area or the non-parallel section, and regional self-adaptive compensation is carried out based on the judgment result; introducing a compensation item formed by the coupling zero-sequence current and the coupling zero-sequence current compensation coefficient into a measurement impedance calculation formula for grounding distance protection, and calculating to obtain corrected measurement impedance; if the corrected measured impedance meets the amplitude criterion and the phase angle criterion at the same time, a tripping signal is sent out.

The invention provides a peak overcurrent protection system and method for a three-phase rectification power supply, and relates to the technical field of circuit protection, and the method comprises the steps: carrying out the clustering analysis of multi-dimensional electric quantity data during the operation of the three-phase rectification power supply, constructing a state recognition model, and obtaining a risk early warning signal of the operation state of the three-phase rectification power supply; according to the risk early warning signal and the constraint condition of the three-phase rectification power supply, reactive current compensation amount is calculated, and a reactive current control instruction is obtained; executing the reactive current control instruction to inject reactive current into the three-phase rectification power supply, and monitoring to obtain change characteristics of electrical characteristics of a port of the three-phase rectification power supply; and performing protection logic judgment on the basis of the current amplitude change rate and the phase deviation characteristic in the change characteristic to obtain a fusion judgment result, and outputting a tripping signal and executing overcurrent isolation. According to the application, peak current advanced interception and multi-criterion collaborative decision based on intelligent early warning can be realized; therefore, over-current protection from passive cut-off to active defense is completed.

The invention discloses a new energy transmission line fault phase selection method and system based on impedance compensation, and relates to the technical field of power system relay protection, and the method comprises the steps: calculating the zero-sequence current and negative-sequence current of the installation position of a relay protection device based on the three-phase current of a to-be-detected line; if the zero-sequence current is larger than a preset zero-sequence threshold value and the negative-sequence current is larger than a preset negative-sequence threshold value, the back-side zero-sequence impedance and the back-side negative-sequence impedance of the installation position of the relay protection device are calculated respectively, a zero-sequence current compensation coefficient and a negative-sequence current compensation coefficient are calculated, and the zero-sequence current and the negative-sequence current are compensated and corrected respectively; the compensated zero-sequence current and the compensated negative-sequence current are obtained, and a target phase selection criterion and an impedance auxiliary phase selection criterion are constructed; and carrying out outgoing line fault phase selection on the to-be-detected line based on the target phase selection criterion and the impedance auxiliary phase selection criterion. The technical problem that a traditional phase selection mode based on phase comparison is prone to misjudgment or failure is solved.

This application discloses a current compensation control method, apparatus, and electronic device. The method includes: monitoring whether compensation conditions are met for a target output channel in a current closed-loop chip; the current closed-loop chip can output a target current through closed-loop control using a drive current; the current closed-loop chip includes at least one output channel, each output channel being used to output a corresponding current; the target output channel is the output channel that outputs the target current from at least one output channel; if the compensation conditions are met, detecting whether a fault exists in the target output channel; if a fault exists in the target output channel, performing: monitoring whether the compensation conditions are met; if no fault exists in the target output channel, performing an automatic zeroing process on the target output channel, the automatic zeroing process being used to achieve current compensation for the target output channel.

The invention discloses a power fluctuation suppression method and system based on an LCC and an MMC. The method comprises the following steps: collecting operation state data of a receiving end converter and electrical operation data of a system in real time; according to the operation state data of the current converter at the receiving end, whether commutation failure occurs at the receiving end is judged; when it is judged that commutation failure occurs, joint calculation is performed based on system electrical operation data and a preset sending end hybrid cascade analysis model, and a reactive compensation instruction for the MMC and a current compensation instruction for the LCC are generated; and the reactive compensation instruction is sent to the MMC at the rectification side, the current compensation instruction is sent to the LCC at the rectification side, and transient active power fluctuation suppression of the DC system is realized through cooperative regulation and control of the MMC and the LCC. According to the invention, the transient stability and power transmission capability of the DC system after the commutation failure are obviously improved, and the problem of active power transmission drop of the DC system after the commutation failure of the sending-end hybrid cascade DC power transmission system is solved.

The application discloses a winding control method and system, and relates to the technical field of capacitor production control. The method further subdivides the acceleration process and the deceleration process of the winding shaft S curve planning track into multiple running stages such as jiajia acceleration, jiajia deceleration, jiajia deceleration, jiajia deceleration and the like, so that the acceleration of the planning track continuously changes between the running stages; according to the current running stage, the current planning position and the current planning linear velocity of the current period are acquired; the current compensation linear velocity is determined based on the feedback compensation mechanism, the current planning position and the actual position, the corresponding position deviation is determined by using the current planning position and the actual position, the angular velocity of the winding shaft is determined according to the current winding diameter, the current compensation linear velocity and the current planning linear velocity, and winding processing is performed. It can ensure that the linear velocity of the winding shaft follows the specification linear velocity synchronously, ensure the constant tension in the winding process, and also effectively avoid the tension control precision decline caused by the deviation.

The invention relates to a current detection method and device of an energy storage system and a storage medium, and belongs to the technical field of energy storage, and the method comprises the steps: obtaining a current no-load mode and a sampling current of a to-be-detected target battery in the energy storage system; acquiring a current correction coefficient corresponding to the current no-load mode; under the condition that the sampling current belongs to the first data range, correcting the sampling current based on the current correction coefficient to obtain a corrected current; the problem that the result of the compensated current is inaccurate due to the fact that current compensation is carried out in a fixed compensation mode in a traditional current detection method can be solved, and due to the fact that different no-load modes correspond to different current correction coefficients, the current correction coefficient corresponding to the current no-load mode is used for correcting the sampling current, and the accuracy of the current correction coefficient is improved. It can be ensured that the current correction coefficient can adapt to different no-load scenes of the energy storage system, and the accuracy of current correction is ensured.

The invention discloses a power distribution network distributed current compensation method and system adaptive to a photovoltaic converter cluster, relates to the technical field of distributed power distribution network current compensation, and aims to solve the problems of response delay and poor safety collaboration caused by complex calculation and neglect of converter capacity limitation of a power distribution network imbalance compensation method. Unbalanced component decoupling is carried out on transformer outlet three-phase electric quantity to accurately obtain a total unbalance compensation instruction so as to lock the unbalance component from the source, margin calculation is carried out based on each converter capacity coefficient to generate an unbalance compensation coefficient, and the overall compensation potential of a cluster is further quantified. Classifying and simplifying the total imbalance compensation instruction according to the cluster cooperative compensation capability to obtain a rated compensation current limit value; and finally, generating a target compensation current instruction of each converter through adaptive weighted fusion processing, and realizing rapid and accurate compensation of the unbalanced current of the power distribution network on the premise of ensuring safe operation of the converter.

The application provides a current compensation method of a three-phase inverter, which comprises the following steps: obtaining the counter-current power error of each phase of the three-phase inverter; for each phase of the three-phase inverter, taking the phase as a target phase, determining a compensation value adjustment amplitude according to the counter-current power error of the target phase; adjusting a preset compensation value according to the compensation value adjustment amplitude to obtain an adjusted compensation value; compensating the given current of the target phase according to the adjusted compensation value to obtain a compensated given current; and performing current control on the target phase according to the compensated given current. Through the above method, the power in and out of each grid-connected point of the three-phase inverter can be stabilized to approach 0 in the phase-independent anti-counter-current scene of unbalanced load.

This invention discloses a method and system for selecting fault lines in resonant grounding systems based on the harmonic characteristics of fault current. After a fault occurs, the zero-sequence voltage of the bus and the zero-sequence current of each feeder are collected. The zero-sequence voltage and zero-sequence current are then filtered and normalized to obtain normalized zero-sequence voltage and zero-sequence current. Based on the normalized zero-sequence voltage and zero-sequence current, a capacitor current compensation model is constructed to calculate the fault current signal of each feeder. Harmonic extraction based on fundamental wave shift is performed on the fault current signal to obtain the harmonic components in the fault current signal of each feeder. The harmonic energy ratio and kurtosis index of the harmonic components of each feeder are calculated respectively, and a comprehensive criterion is constructed to select the faulty line. This invention can reliably initiate single-phase grounding faults in distribution networks and identify faulty feeders under high-resistance grounding and arc-type grounding conditions, improving the accuracy of fault diagnosis and engineering applicability.