156results about "Active power filtering" patented technology

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 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.

Systems and methods for supplying power (both active and reactive) at a medium voltage from a DCSTATCOM to an IT load without using a transformer are disclosed. The DCSTATCOM includes an energy storage device, a two-stage DC-DC converter, and a multi-level inverter, each of which are electrically coupled to a common negative bus. The DC-DC converter may include two stages in a bidirectional configuration. One stage of the DC-DC converter uses a flying capacitor topology. The voltages across the capacitors of the flying capacitor topology are balanced and switching losses are minimized by fixed duty cycle operation. The DC-DC converter generates a high DC voltage from a low or high voltage energy storage device such as batteries and / or ultra-capacitors. The multi-level, neutral point, diode-clamped inverter converts the high DC voltage into a medium AC voltage using a space vector pulse width modulation (SVPWM) technique.

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 control method and system for a hybrid active power filter and a storage medium, and the method comprises the steps: taking an inductance value and a capacitance value of a passive power filter as the input of a particle swarm optimization method, and obtaining an optimized inductance value and an optimized capacitance value; when the harmonic wave frequency filtered by the passive power filter is the same as the harmonic wave frequency filtered by the active power filter, the active power filter is equivalent to a virtual LC filter with the same structure as the passive power filter; otherwise, enabling the active power filter to be equivalent to a virtual resistor; obtaining a harmonic compensation current reference value of the active power filter; and superposing the harmonic compensation current reference value and the reactive compensation current reference value to obtain the total reference current of the active power filter, taking the total reference current as the input of a proportional resonance controller, and performing PWM modulation on the output of the proportional resonance controller. According to the invention, the harmonic current amplification problem of the passive power filter is eliminated, and the stability and compensation performance of a power system are improved.

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 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.

A hybrid uninterruptible power supply includes a power conversion unit including a converter electrically connected to a first external alternating current (AC) power source, an inverter electrically connected to an output of the converter and to a load, and a power storage unit electrically connected between the converter and the inverter, a current thrupass unit electrically connected to the first external AC power source and electrically connected to the load and including a first thyristor, a current bypass unit including a second thyristor and a switch electrically connected in parallel to the second thyristor, the second thyristor being electrically connected to a second external AC power source and electrically connected to the load, and a controller configured to control the power conversion unit, the current thrupass unit, and the current bypass unit.

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 discloses a parallel APF harmonic suppression method based on SVPWM for charging pile grid connection. The parallel APF harmonic suppression method comprises the following steps that an uncontrolled direct current charging pile typical model is built; nonlinear load harmonic waves in the typical model of the uncontrolled direct current charging pile are detected; taking the chaos sequence as a spread spectrum signal, and superposing the spread spectrum signal on a reference frequency signal to replace a fixed switching frequency of SVPWM (Space Vector Pulse Width Modulation) so as to suppress high-frequency noise waves of an APF (Active Power Filter) system; and a PI control strategy based on a chaos period is adopted to generate a compensation current to treat the detected nonlinear load harmonic waves. And the harmonic suppression effect is enhanced.

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 an active power filter control method in a hybrid compensation system and a computer device. The hybrid compensation system comprises a power grid, an active power filter and a passive power filter. The active power filter and the passive power filter are connected in parallel between a power grid and a load. According to the invention, the APF is controlled to simulate the resistance at the harmonic frequency to realize harmonic suppression of the load, so that the current resonance amplification of the PPF can be avoided when the APF and the PPF compensate the harmonic at the same frequency, and the stable operation of the hybrid compensation system is ensured.

The invention discloses a method and a system for controlling an APF (active power filter) multi-machine parallel system, which are suitable for a system in which N APFs run in parallel. The system comprises two stages of control units, a central controller is a first-stage control unit, and each APF controller is a second-stage control unit. The first-stage control unit calculates a feed-forward coefficient according to the rated compensation capacity of each APF and transmits the feed-forward coefficient to the second-stage control unit; the second-stage control unit detects harmonic current through current sensors connected to the network side and the load side and then outputs compensation current. The output current feedback signal is subtracted from the reference current signal, so that the reference current and the output current are proportionally reduced, and the output current of each APF is automatically distributed according to the rated capacity proportion; the compensation precision of the system can be improved according to the feed-forward coefficient transmitted by the first-stage control unit. According to the method, the flexibility, the expansibility and the reliability of the APF multi-machine parallel system can be improved, and when a central controller fails or equipment communication fails, each APF can still operate independently, and compensation current is automatically distributed.

The utility model relates to the technical field of APF filters, and discloses a heat dissipation device for an APF filter, which comprises a filter body, a heat dissipation groove is formed in one side of the filter body, a heat dissipation net is embedded in the heat dissipation groove, supporting plates are arranged on the front side and the rear side of the heat dissipation net, a cleaning brush is arranged on one side of each supporting plate, and the cleaning brush is arranged on the other side of each supporting plate. One side of the cleaning brush abuts against the filter body, a connecting column is slidably connected to the interior of the supporting plate, the two ends of the connecting column are fixedly connected with fixing bases, and the problem that a large amount of dust and sundries are accumulated on a heat dissipation net due to long-time heat dissipation of an existing APF is solved. The impurities not only affect the ventilation effect of the heat dissipation net, but also may block holes of the heat dissipation net to reduce the heat dissipation efficiency, and after the heat dissipation performance of the equipment is gradually reduced, the internal temperature of the equipment is increased, and a series of performance problems, such as unstable operation and reduced efficiency, may be caused.

The embodiment of the invention provides a delay-free dynamic tracking APF current inner loop control system and control method. The system comprises a control module and an actual circuit. The control module comprises a voltage acquisition module, a current acquisition module, a voltage prediction module, a current prediction module, a voltage generation module, an amplitude limiting module, a time delay module and a PWM generation module; according to the technical scheme, the current value and the voltage value of the network side at the current moment are collected, the current value and the voltage value are used for prediction to obtain the prediction signal, the voltage control signal is obtained according to the prediction signal and the compensation current instruction, the APF controls the output voltage according to the voltage control signal, the APF inverter acts on an actual circuit, and therefore the current compensation effect is achieved. Therefore, the dynamic performance of the existing APF current control algorithm is greatly improved, the delay of the current control response is reduced, and the non-delay dynamic tracking of the current instruction is realized.

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.

Techniques are described for testing whether an end effector, or component thereof, is correctly or incorrectly installed to a manipulation system. In an example, a manipulation system can include a manipulator arm configured to receive an end effector having a first moveable jaw, a transducer configured to provide first effort information of the end effector as the end effector moves, and a processor configured to provide a command signal to effect a first test move of the first moveable jaw, and to provide an installation status of the of the end effector using the first effort information of the first test move.

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.

Techniques are described for testing whether an end effector, or component thereof, is correctly or incorrectly installed to a manipulation system. In an example, a manipulation system can include a manipulator arm configured to receive an end effector having a first moveable jaw, a transducer configured to provide first effort information of the end effector as the end effector moves, and a processor configured to provide a command signal to effect a first test move of the first moveable jaw, and to provide an installation status of the end effector using the first effort information of the first test move.

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.

This invention provides a control method for the active section of a hybrid power active filter. By employing a three-phase fictitious and improved symmetrical component method, it can perform electrical quantity calculations under severely asymmetrical three-phase nonlinear load conditions, extracting the zero-sequence current component, which contains zero-sequence harmonic currents. Furthermore, due to the use of a triangular wave comparison control method, the resulting PWM pulse signal contains fewer harmonics. Using this PWM pulse signal to control the active section of the hybrid power active filter enables effective control and accurate filtering of zero-sequence harmonic currents. In summary, the control method of this invention enables the hybrid power active filter to accurately filter zero-sequence harmonic currents under severely asymmetrical three-phase nonlinear load conditions, achieving an ideal filtering effect.

The utility model discloses power electronics equipment's test and debugging technical field relates to a kind of debugging device for active filter;Including cabinet;The cabinet inside is provided with voltage regulator, control module and power module;The control module is located above voltage regulator;The cabinet side is provided with aviation plug;The power module and voltage regulator are electrically connected;The voltage regulator and aviation plug are electrically connected;The aviation plug is electrically connected with active filter and control module respectively;The active filter and mutual inductor are electrically connected;The mutual inductor and control module are electrically connected;The voltage regulator and intelligent electric meter are electrically connected;The intelligent electric meter and control module and electrically connected.The utility model can realize the quick power-on test of active filter, parameter adjustment and performance verification.

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 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.

A cascaded multilevel converter is disclosed. The converter comprises a plurality of modules coupled together to form a branch, each of the modules comprising a switching circuit and a DC link for supplying a DC voltage to the switching circuit. The converter further comprises a controller for controlling the switching circuit of each module to generate an AC voltage in the branch, wherein the controller is configured to: determine, for each module, a voltage across a capacitor of the DC link of the module; determine, for each module, a reference power value for charging the capacitor of the DC link of the module to a reference voltage value for the module; determine, from the reference power values of the modules, a common reference AC current value for AC current in the branch; and determine, from the common reference AC current value, a common reference AC voltage value for an AC voltage in the branch.

Using an active filter to suppress oscillations. A device (50) for controlling a converter (9, 15) of a power generation system, in particular a wind turbine (1), is described. The converter is connected to a connection point (21) to a public power grid (23). The device includes: a measurement section (31) adapted to provide measurement values indicating the values of the current (33) and voltage (35) at the connection point (21); a main converter controller (27) adapted to receive the measurement values (33, 35) and generate a main converter control signal (37) based on the measurement values; an active filter system (29) adapted to receive the measurement values (33, 35) and generate an active filter control signal (39) based on the measurement values; an adder element (30) adapted to add the main converter control signal (37) and the active filter control signal (39) and supply the sum signal (41) as a control signal to the converter (9, 15).

The invention relates to a control method for a parallel active power filter based on harmonic voltage suppression, and belongs to the technical field of power control. Three-phase power grid voltages are respectively obtained through a sensor, and a compensation current instruction of each selected subharmonic of each phase is calculated and determined through a second-order band-pass filter bank of selected subharmonic; determining an instantaneous value instruction of the compensation current of each selected subharmonic of each phase according to the transfer function, summing the instantaneous value instruction of the compensation current of each selected subharmonic corresponding to each phase, determining a total instruction of the selected subharmonic of each phase, and sending the total instruction to a current control loop; and the current control loop modulates and drives the voltage type inverter through the PWM driving module, so that the compensation current waveform formed by the voltage type inverter is consistent with the total instruction current waveform, and the compensation current is input to the power grid. The safety and stability of the harmonic suppression process are improved.