165 results about "Active power filter" patented technology

The invention relates to the technical field of power electronics, in particular to a control method for a low-voltage intelligent reactive compensation system of a submerged arc furnace. Comprising the following steps: acquiring three-phase voltage, current, power factor, harmonic content and temperature parameters of the low-voltage side of the submerged arc furnace through a sensor network; the load fluctuation of the submerged arc furnace in the future 1-5 minutes is predicted based on a deep learning algorithm, and a compensation demand pre-judgment value is generated; according to a load prediction result and a real-time working condition, performing dynamic switching from three modes of fixed compensation, grouped switching and continuous adjustment; harmonic component dynamic tracking compensation is carried out by combining an active power filter (APF) and a static var generator (SVG); the system overvoltage, overcurrent and temperature parameters are monitored in real time, and a grading protection mechanism is triggered and fed back to the compensation strategy adjusting module. The invention provides a control method for a low-voltage intelligent reactive compensation system of a submerged arc furnace so as to improve the response speed of the system, prolong the service life of equipment and guarantee the electric energy quality of a power grid.

The invention provides an APF and SVG cooperative control-based electric energy quality comprehensive treatment system, and belongs to the technical field of intelligent power grid industry and electric energy quality comprehensive treatment, and the system comprises the steps of obtaining a power grid current signal and a voltage signal, and detecting a harmonic component and a voltage deviation through a harmonic detection module; a collaborative decision controller is adopted to determine a compensation strategy according to the harmonic component and the voltage deviation, and compensation tasks of an active power filter channel and a static var generator channel are distributed; harmonic compensation current is generated through an active power filter channel, and high-frequency harmonics are suppressed; reactive compensation current is generated through a static var generator channel, and voltage fluctuation is stabilized; and the compensation current is filtered through the filtering module and is output to a power grid. The electric energy quality comprehensive treatment system can effectively inhibit power grid harmonic waves, stabilize voltage fluctuation and improve electric energy quality, and is suitable for a complex power grid environment.

The invention belongs to the related technical field of photovoltaic inverter compensation systems, and particularly relates to a high-power-quality converter with chopping inversion multiplexing, which comprises series and parallel APFs (active power filters), a Z-type grounding transformer, a three-phase bridge circuit and a photovoltaic power generation unit, one end of the transformer is connected to the alternating current side of the bridge circuit, the other end of the transformer is externally connected with a load power grid, a grounding point is led out to be connected to one end of the photovoltaic power generation unit while the transformer is connected to the alternating current side, and the other end of the photovoltaic power generation unit is connected to the bridge circuit; the series APF and the parallel APF form a unified power quality controller and are connected between the transformer and the bridge circuit; the parallel APF is used for compensating voltage sine distortion and voltage imbalance in the presence of an inversion working condition, and the series APF is used for filtering harmonic current and compensating reactive power in the presence of the inversion working condition; and the transformer is used for providing a grounding reference for the photovoltaic power generation unit in the presence of a chopping working condition and offsetting a zero-sequence harmonic component of the alternating current side voltage in the presence of an inversion working condition.

The invention belongs to the technical field of power electronics, and provides a method and a system for improving harmonic transient stability of a grid-forming type active power filter, droop control is performed on a deviation value of an active power reference instruction and an actually measured active power value, integration is performed to obtain a power angle, and the power angle and a grid-side harmonic phase are added to generate a harmonic voltage phase instruction; pI control is carried out on a deviation value between the reactive power reference instruction and an actually measured reactive power value to obtain a voltage deviation value, and the voltage deviation value and a network side specified subharmonic voltage amplitude are summed to generate a harmonic voltage amplitude instruction; taking a harmonic voltage amplitude instruction as a d-axis reference, taking 0 as a q-axis reference, respectively subtracting the d-axis reference and the q-axis reference from the harmonic voltage on the d-axis and the q-axis to obtain deviation values, and obtaining a dq component of the harmonic voltage reference through PI control. The operation safety of the power grid can be improved.

The invention relates to the technical field of power filters, and discloses a fault-tolerant control method, system, equipment, medium and product for an active power filter, and the method comprises the steps: building an observer of a fault sensor through the type of the fault sensor after the type of the fault sensor of the active power filter is determined, and outputting an observation value through the observer; and fault-tolerant control is carried out on the fault sensor through the observed value, so that the fault-tolerant control is carried out on the power grid voltage sensor, the inverter output current sensor and the direct current side voltage sensor without changing a modulation strategy, and the accuracy of fault-tolerant control of the active power filter is improved; and stable operation and reliability of the system of the active power filter are ensured.

The invention discloses a unified control method for harmonic waves by a photovoltaic inverter and an active power filter, and the method comprises the steps: detecting load reactive and harmonic current, converting the load reactive and harmonic current into reactive and harmonic compensation instruction current, and carrying out the maximum power point tracking of a solar photovoltaic array, thereby obtaining active grid-connected instruction current; and then the reactive power and harmonic compensation instruction current and the photovoltaic grid-connected instruction current can be combined, and then a current tracking control method is used for controlling a converter to inject the combined instruction current into a power grid. At night or in cloudy and rainy days, the photovoltaic grid-connected power generation system cannot work due to no electric energy output, and at the moment, the photovoltaic inverter is directly used as an active power filter to compensate reactive power and harmonic current generated by nonlinear equipment and improve the power supply performance of a power grid, so that the photovoltaic grid-connected power generation can be completed on the same device, and the power supply efficiency is improved. Harmonic suppression and reactive compensation are realized, so that a photovoltaic grid-connected power generation system always operates in an optimal economic mode, and equipment investment is effectively saved.

The invention discloses a variable current control device of a frequency converter. The variable current control device comprises a main circuit topology and a system-level control module, the system-level control module comprises a power calculation module, a voltage generation module, an active power filter module and a PWM generation module; the power calculation module is used for calculating the reactive power of the frequency converter according to the sampling voltage at the common coupling point and the three-phase compensation current generated by the frequency converter; the voltage generation module is used for performing power control according to reactive power and direct-current side sampling voltage of the frequency converter and generating a three-phase voltage signal; the active power filter module is used for performing harmonic compensation based on the three-phase voltage signal to obtain a modulation voltage signal; and the PWM generation module is used for generating a pulse width modulation control signal according to the modulation voltage signal and inputting the pulse width modulation control signal into the H-bridge circuit. Power control is performed through the system-level control module to realize reactive power compensation, and harmonic compensation is performed on the main circuit topology, so that the electric energy quality of the power supply is improved.

The invention relates to a harmonic suppression and dynamic voltage compensation method based on a composite control series filter, and belongs to the field of power electronic technology and electric energy quality control. Harmonic current passing through a primary winding of a transformer and a sudden rising or falling signal of power supply voltage are extracted, and after the two signals are controlled and combined into a reference signal, a voltage source inverter (VSI) connected with a secondary side of the transformer in parallel shows a controllable voltage characteristic. The control parameters of the harmonic current can enable the transformer to present relatively large controllable impedance to harmonic waves, so that harmonic wave isolation is realized. In addition, the VSI compensates for the system voltage deviation by detecting the voltage drop. And finally, establishing a simulation model to verify that the series active power filter based on the control strategy can isolate harmonic waves and effectively compensate voltage deviation. Harmonic suppression and dynamic voltage compensation functions can be realized at the same time, and the power quality of a middle-high voltage system is improved.

The invention provides a phase delay test and compensation method for an active power filter, and the method comprises the steps: generating a sine wave control signal with the frequency range of 1 kHz to 20 kHz through an FPGA, and driving a half-bridge inverter of the active power filter to output an analog signal; measuring delay time of three delay links in the active power filter by modules, wherein the delay time comprises delay 1 of an error detection link, delay 2 of an inversion link and delay 3 of a digital processing link; and taking the sum of the delay 1 of the error detection link, the delay 2 of the inversion link and the delay 3 of the digital processing link as the total delay of the system, introducing a phase compensation parameter in an LMS algorithm, and adjusting the phase of the offset current to enable the phase difference between the offset current and the harmonic current of the power grid to be 180 + / -5 degrees. According to the technical scheme, the delay parameter in the active power filter can be measured, phase alignment of the output signal of the active power filter and the harmonic current in the power grid is achieved in a compensation mode, and suppression of the harmonic current of the power grid is achieved.

The invention discloses an active power filter residual life evaluation method, system and device, a medium and a product, and the method comprises the steps: constructing a failure degradation model of a DC side capacitor of an active power filter and a failure degradation model of an IGBT power module through a Wiener process; determining an edge cumulative distribution function of the direct-current side capacitor and an edge cumulative distribution function of the IGBT power module, coupling the edge cumulative distribution function of the direct-current side capacitor and the edge cumulative distribution function of the IGBT power module by using a Copula function, and based on a joint degradation probability distribution model, performing Monte Carlo simulation to obtain a degradation probability distribution model. According to the method, the degradation tracks of the direct current side capacitor and the IGBT power module from the starting moment to the future moment are simulated, and when any one degradation track passes through the failure threshold value, the latest moment is determined as the degradation moment, so that the residual life estimation value of the active power filter is determined, and the precision of residual life estimation is improved.

The invention discloses an active power filter control method and system suitable for frequency fluctuation, and the method employs an FIR filter based on a Lagrange interpolation method to correct the decimal part of the sampling times, and employs a variable bandwidth adjustment internal model control (VBAI) technology to improve the bandwidth after frequency fluctuation. The problem that the control effect is seriously reduced due to the fact that traditional repeated control sampling times change caused by power grid frequency fluctuation is effectively solved, and control gain stability under frequency fluctuation is guaranteed.

The invention discloses a repetitive control method and device for an active power filtering device, and the method comprises the steps: carrying out the adjustment of the harmonic frequency of a controller according to a harmonic signal obtained from a main circuit of the active power filtering device, calculating the harmonic signal through a harmonic detection module of the adjusted controller, obtaining a fixed delay parameter, and carrying out the calculation of the fixed delay parameter. And calculating according to the fixed delay parameter and the voltage frequency output by the power grid phase-locked loop to obtain a delay parameter so as to judge whether the harmonic signal needs to be compensated or not, if so, calculating a corresponding compensation parameter according to the delay parameter, and outputting a corresponding compensation current according to the compensation parameter to compensate the harmonic signal. Corresponding parameters of the controller are adjusted according to the harmonic frequency of the harmonic signal, adaptive adjustment of different harmonic scenes is achieved, and adaptability and universality to the different harmonic scenes are improved; through the repetitive control method, repetitive tracking control is carried out on the harmonic signals, and signal delay, storage resource waste and repetitive control operation complexity are reduced.

The invention provides a moisture-proof and dust-proof ventilation type active power filter, and relates to the technical field of electric power. The moisture-proof and dust-proof ventilation type active power filter comprises a microcomputer controller, an installation box, a dehumidification box and a filter body. A second fan sucks away air in the mounting box, air enters through multiple sets of ventilation windows at the same time, the purpose of ventilation and heat dissipation is achieved, a filter screen is arranged on the inner side wall of each ventilation window and can play a dustproof role in the ventilation process, dehumidification particles adsorb moisture in the mounting box to play a damp-proof role, and a first fan blows the filter screens in the reverse direction; the filter screen is subjected to dust removal and regeneration, the manual maintenance frequency is effectively reduced, moisture absorption saturated dehumidification particles rotate to the position above the air inlet hole, the microcomputer controller controls the electric heating wire to be powered on, heated air is blown into the corresponding dehumidification cavity through the second fan, and therefore the purposes of heating and regeneration of the dehumidification particles are achieved. And the manual maintenance frequency is further reduced.

The invention discloses a method for suppressing input three-phase harmonic current of ship power supply equipment, which comprises the following steps of: firstly, determining the times and loop parameters of specific harmonic current needing to be compensated by a PFC (Power Factor Correction) unit of the power supply equipment under the working condition by combining a CE101 test chart and the size of an array load, so that harmonic current control participates in the existing PFC current loop control; therefore, the content of the input harmonic current is adjusted to be lower than the CE101 limit value. On the basis of a PFC digital control unit of original equipment, a control method for suppressing input of three-phase harmonic current is added, and an electric reactor or an active power filter (APF) device is omitted, so that the problem that part of sub-harmonic current exceeds a CE101 limit value is solved.

The invention provides a harmonic detection and treatment method and equipment used in an electric power system, and belongs to the technical field of electric power systems, and the method specifically comprises the steps: determining the harmonic influence type of a switch cabinet according to the temperature monitoring data of the switch cabinet in different harmonic current intervals, according to the method, the monitoring load interval is determined according to the switch cabinet data of different harmonic influence types, and when the switch cabinet is in the monitoring load interval of the active filter, whether harmonic detection processing is needed is determined according to the temperature detection data of the switch cabinets of different harmonic influence types, so that the working stability and reliability of the active filter are improved.

The invention provides a harmonic protection device for electric energy management, which comprises a cabinet body, a cabinet door is arranged on one side of the cabinet body, a partition plate parallel to the bottom of the cabinet body is arranged in the cabinet body, the partition plate is slidably arranged in the cabinet body in the vertical direction, and an air guide cylinder assembly is arranged on the partition plate in the vertical direction. The power filter is arranged in the air guide cylinder assembly, the air guide cylinder assembly is provided with a dust sweeping brush corresponding to the outer side of the power filter, a reciprocating driving mechanism for driving the partition plate to reciprocate up and down is arranged in the cabinet body, and the reciprocating driving mechanism is in transmission connection with the air outlet fan; in the heat dissipation device, the reciprocating driving mechanism drives the partition plate to move up and down in the heat dissipation process, the outer side of the power filter can be swept up and down through the dust sweeping brush in the air guide cylinder assembly, dust is prevented from adhering to the outer side of the power filter, dust adhering to the outer side of the active power filter can be reduced, and the heat dissipation effect of the active power filter is guaranteed; and the performance reduction caused by over-high temperature is avoided.

The application discloses a harmonic compensation and stability improvement method, system, medium and equipment, filters components of a grid voltage in a two-phase static coordinate system to obtain corresponding fundamental components; subtracts the fundamental components of the grid voltage from the components of the grid voltage in the two-phase static coordinate system to obtain total harmonic components of the grid voltage; filters the total harmonic components of the grid voltage by using multiple band-pass filters to obtain multiple harmonic components corresponding to frequencies; subtracts reference current instructions of an active power filter from the multiple harmonic components, and inputs the result as a new current reference instruction into a current controller; and based on a virtual harmonic admittance method, outputs harmonic compensation currents through current inner loop control in the two-phase static coordinate system to realize harmonic compensation on a nonlinear load with frequency coupling characteristics and suppression of harmonic compensation oscillation. The application can adapt to various complex grid environments and has relatively practical engineering application value.

The invention relates to the technical field of power electronics, and discloses a fusion type frequency division converter which comprises a main power conversion unit based on an IGCT tube, an active power filtering unit based on an IGBT tube and an output unit, the first end of the main power conversion unit is connected with direct current, and the second end of the main power conversion unit is connected with the first end of the output unit; the first end of the active power filtering unit is connected with the second end of the output unit, and the second end of the active power filtering unit is grounded; the third end of the output unit is connected with the to-be-powered device. The application range of the IGCT is widened to the fields of new energy power generation, energy storage and the like, and the advantages of the IGCT are fully played by reducing the switching frequency, so that the current situation that new energy power generation and energy storage are exclusively occupied by an IGBT is broken through.

The utility model provides a harmonic suppression cabinet, which comprises a cabinet body, and an active power filter, an air switch and terminal assembly, a current transformer, an electric reactor and a fan which are respectively arranged in the cabinet body, an air inlet and the fan are respectively arranged on two opposite side walls of the cabinet body; the active power filter is arranged above the air switch and terminal assembly to form a first parallel assembly; the current transformer is arranged above the reactor to form a second parallel assembly; the first parallel assembly is arranged on the side close to the air inlet, the second parallel assembly is arranged on the side close to the fan, and the cabinet body is provided with an openable cabinet door at the position corresponding to the first parallel assembly. The harmonic suppression cabinet provided by the utility model is reasonable in internal component layout, compact in structure, small in overall size and convenient to maintain.

The utility model discloses a power control module and device, the power control module comprises a control circuit and a plurality of control modules connected with the control circuit, and each control module comprises a switch unit, a contactor, an active power filter and an output port. The control circuit is connected with the switch units in the control modules so as to control on-off of the switch units, the first ends of the switch units are connected with power voltage, and the second ends of the switch units are connected with coil terminals of the contactors so as to control on-off between the coil terminals of the contactors and the power voltage. A first contact of the contactor is connected with the input voltage, a second contact of the contactor is connected with the output port, and the active power filter is connected with the first contact of the contactor to filter the input voltage. The power control module and device can simultaneously control the power output of a plurality of channels, solve the problems of automatic timing test and multi-channel test, and improve the test efficiency and convenience.

The application discloses a kind of electric energy metering box systems based on harmonic identification compensation, including signal pre-processing module, offline training module, online inference module and harmonic reconstruction and compensation module.Signal pre-processing module is framed according to time window to the current signal collected, generates frequency spectrum label count vector.Offline training module executes variational expectation maximization training of implicit Dirichlet distribution model to historical frequency spectrum label corpus, learns the frequency spectrum signature distribution and feature template of multiple harmonic source mode.Online inference module solidifies the parameter obtained by training, executes lightweight variational inference iteration, estimates the harmonic source mixing proportion vector of current frame.Harmonic reconstruction and compensation module carries out weighted vector synthesis to mixing proportion vector and feature template, generates compensation current reference signal output to active power filter.The application can realize sub-millisecond level real-time harmonic source mode identification and compensation in resource-limited embedded environment.

The application discloses an active power filter control method for preventing resonance, and relates to the technical field of power quality control.The method injects a harmonic current with a frequency of a pre-judged harmonic frequency into a power supply circuit, compares the change in the grid-side current and the load-side current before and after the injection, obtains a sensitive frequency point, separates the harmonic component corresponding to the sensitive frequency point from the harmonic components corresponding to other frequencies, and respectively generates compensation currents, wherein the harmonic component corresponding to the sensitive frequency point is adjusted through a feedback coefficient, different compensation currents are superimposed to obtain a comprehensive compensation current, the comprehensive compensation current is used to offset the load harmonic current, and the grid-side current is ensured to be undistorted.The technical scheme in the application can realize harmonic impedance adjustment, effectively prevent harmonic amplification, avoid passive element burning or power supply failure, and enhance the safety and reliability of power supply.

A control system including a power grid configured to supply a grid voltage, a filter capacitor and a filter inductor each connected in parallel to the power grid, a filter current meter connected in series to the filter inductor, an active power filter connected to the filter current meter, a nonlinear load connected in series to the power grid, and a modulated model predictive controller (MMPC) configured to generate a control signal for operating the active power filter.

The invention relates to the technical field of active power filtering equipment, and discloses active power filtering equipment convenient to maintain, the active power filtering equipment convenient to maintain comprises a bottom plate, the outer side of the bottom plate is fixedly provided with supporting legs, and the outer side of the bottom plate is provided with a maintenance assembly, a trigger assembly, a dustproof assembly and a supporting assembly. The maintenance assembly comprises a hollow vertical rod, one end of the hollow vertical rod is fixedly installed on the outer side of the bottom plate, and a hollow transverse rod is fixedly installed on the outer side of the hollow vertical rod. According to the active power filtering equipment convenient to maintain, in order to enable the equipment to be maintained more conveniently and quickly, a maintenance assembly is arranged and cooperates with a door plate to open a buckle structure so as to open a side plate, and meanwhile, in daily life, a motor drives a fan to rotate, so that the maintenance efficiency is improved. Through the hollow vertical rod, the hollow cross rod, the circular opening, the concentric-square-shaped groove, the air inlet groove and the long groove, the filtering equipment is well cooled, and the maintenance frequency of the device is reduced.

The utility model relates to the technical field of electrical connection, in particular to an electricity-saving and energy-saving terminal electrical comprehensive treatment protection module, which comprises a central control module used for data processing and circuit integral control, and an enhanced active power filter module used for adjusting three-phase imbalance, the bus capacitor module is used for balancing current of each phase through charging and discharging, and the enhanced active power filter module comprises a sampling module used for detecting voltage and current of a system side in real time; and the compensating current generating circuit is used for controlling the on-off of the three-phase circuit to absorb energy from the power grid and mutually convert the energy among the three-phase circuit so as to enable the three-phase current to reach a balanced state. According to the utility model, real-time detection of system side current can be carried out, on-off of the three-phase circuit is controlled, energy is absorbed from a power grid and is mutually converted among the three-phase circuit, so that three-phase current reaches a balance state, and the like, thereby eliminating total harmonic distortion of the power grid with low harmonic, compensating reactive power, improving power factor of the power grid, and reducing power consumption. And an energy-saving node effect is achieved.

The invention relates to the technical field of power system automation and electric energy quality control, in particular to an electric energy quality optimization control method and system based on distributed collaborative decision. The method comprises the following steps: deploying synchronous phasor measurement units and corresponding edge intelligent decision nodes at a plurality of nodes of a power grid, and constructing a distributed network; each node calculates an electric energy quality characteristic index based on local data; dynamic role negotiation is carried out through local communication, and a leading controller is determined; the dominant controller fuses strategies and confidence information of local and adjacent nodes to generate a cooperative control strategy; and finally, equipment such as a static var generator and an active power filter is controlled to perform coordinated execution. Through a decentralized collaborative decision-making mechanism, the defects that centralized control is slow in response and low in reliability are overcome, rapid self-adaptive treatment on voltage sag, harmonic waves and other problems is achieved, and the response speed, the treatment success rate and the system robustness are remarkably improved.

The application discloses a kind of multi-module active power filter control methods, comprising: detecting load current effective value, according to the size relationship and duration of load current and preset load current threshold, start or stop the operation of active power filter module;According to the output current of the preset capacity allocation strategy of active power filter module is distributed, and the running load rate of the active power filter module being calculated is operated;According to the size relationship and duration of running load rate and preset expected load rate upper limit and preset expected load rate lower limit, start or stop the operation of active power filter module.By the technical scheme of the application, the function that multiple module output currents are automatically distributed according to the size of load is realized, so as to conveniently realize the control of the whole system output and start-stop current, improve the compensation accuracy effect, prolong the service life of the whole system, improve the stability, reduce the failure rate.

The invention provides a harmonic suppression method, device and equipment for a Hull moving average filter and a medium. The harmonic suppression method comprises the steps of collecting load end current; based on an improved harmonic current detection method, a harmonic current instruction signal is detected and extracted according to a load end current; controlling the harmonic current command signal to pass through an active power filter to generate a compensation current; and the compensation current is injected into the power grid. The technical problems that in a traditional harmonic and reactive current detection method, unavoidable losses are brought to the dynamic response speed and accuracy of current detection, and the harmonic compensation performance of a system is finally affected are solved.

A wind power grid impact damping suppression method based on branch and bound and knapsack optimization control can realize efficient and rapid suppression of wind power fluctuation. The device is characterized by combining the advantages of thyristor switched filter (TSF) and active power filter (APF), and developing active damping generator technology based on knapsack optimization control for wind power grid impact suppression. The developed ADG technology has the following advantages: ① It has the characteristics of TSF harmonic impact suppression, voltage mutation and high cost performance; ② It has the characteristics of APF output damping continuous adjustable and high precision; ③ Based on branch and bound, the wind power impact is classified as the reference of the maximum damping of ADG output, which effectively improves the rapidity and stability of ADG response; ④ The knapsack problem (UKP) is used to realize the optimal switching control of ADG, which meets the minimum cost and efficient wind power disturbance impact suppression.

The invention relates to a wheel polygon wear suppression method, an inter-harmonic excitation suppression circuit, a method and a medium, and relates to the technical field of railway traction transmission. On the basis of inter-harmonic excitation suppression and polygon wear feedback suppression, the malignant feedback effect caused by electromechanical coupling is weakened, and therefore suppression of polygon wear development of the wheel is achieved; the inter-harmonic excitation suppression comprises the following steps of: arranging an active power filter in a direct current link, and compensating direct current link power fluctuation caused by harmonic waves introduced by a rectifier; the polygon abrasion feedback suppression comprises the steps that compensation current is calculated based on the rotating speed fluctuation quantity under polygon abrasion excitation, and the T-axis current of the motor is compensated. According to the scheme, corresponding technical measures can be put forward from the two aspects of inter-harmonic excitation source suppression and polygon wear feedback suppression, comprehensive suppression of development of polygon wear of the wheel is achieved, polygon wear of the wheel caused by electrical parameters is reduced, and the method has the advantages of being low in implementation cost and not prone to being affected by the external environment.