178 results about "Passive filtering" patented technology

An implantable vagal stimulation device with high-energy efficiency and novel data sensing is provided for use in a wide variety of applications where neural stimulation is required, including human heart rate control. The stimulation device uses low-impedance circuitry and digital waveforms to minimize energy losses, thereby requiring a relatively small battery. Front-loaded, passive filtering is employed to reduce electromagnetic noise sensitivity, leaving a clear physiological signal without degradations. This physiological signal is processed by a derivative zero transition detector (DZD), which is immune to variations in input signal dynamic range unlike traditional methods. Information that the DZD receives can be then interpreted and used along with an algorithm to execute appropriate vagal nerve stimulation.

The invention discloses a modified simulated annealing and particle swarm optimization (MPSO-SA) algorithm, which comprises: optimizing a filter device in a power distribution network by introducing an adaptive inertia coefficient and a memory. The adaptive inertia coefficient can be adjusted adaptively, and the algorithm precision can be enhanced; the memory is used for recording the optimal solution which appears during searching; the optimal solution is compared with a final solution after an annealing process is finished, so a whole optimal solution can be obtained; and local optimum of the particle swarm algorithm can be avoided. A simulation result shows that: by the algorithm, installation positions and corresponding parameters of active and passive filter devices are instructed to be optimized uniformly within the range of the power distribution network, so the loss of the system can be reduced; a voltage factor, a power factor and the like are kept within a scheduled range; and an aim of minimizing energy cost of the system and the investment cost of the filter device can be fulfilled.

The device includes voltage detection unit at net side, current detection unit at net side, device of picking-up fundamental current at load side, digital signal processor DSP and control system based on DSP, generator of pulse-width modulation, inverter and LC filter. Structure and control method of combining unsmoothed nonlinear control with observer of expanding state are utilized in the invention. Output, derivative and unknown internal and external interference are observed through observer of expanding state. Harmonic opposite phase compensation is converted to tracking of ideal sine signal. Wattless dynamic compensation is realized through voltage-controlled reactor so as to reduce capacity of inverter to minimum and play filtering action. The invention integrates active filtering, passive filtering and wattless dynamic compensation.

The invention relates to an H-bridge cascade type active power filter. In the invention, an A phase valve circuit LINKA, a B phase valve circuit LINKB, a C phase valve circuit LINKC and a passive filtering inductor branch are connected in a star shape or a triangular shape and then are merged in a power grid. The valve circuit of each phase comprises a common alternating-current bus, a single-phase transformer bank, a direct-current isolation capacitor, an inductor series circuit group, a single-phase H-bridge auxiliary transformer bank, a direct-current voltage support unit direct-current capacitor group and a single-phase H-bridge main convertor group; the single-phase transformer bank comprises m single-phase transformers, and primary windings are connected in parallel through the common alternating-current bus; n secondary windings of the m single-phase transformers are connected with n single-phase H-bridge auxiliary converters through an inductor and the direct-current isolation capacitor group; the n single-phase H-bridge auxiliary converters are respectively connected with n single-phase H-bridge main transformer direct-current voltage support capacitors; and n single-phase H-bridge main converters are connected with the power grid in parallel through the passive filtering inductor branch after being cascaded.

The invention discloses a hydraulic pipeline fluid pulsation attenuation device based on a piezoelectric shunt damping technology. The middle part of an attenuator is a rectangular sealing cavity; left and right ends of the cavity are respectively provided with an inlet circular tube (1) for flowing in a hydraulic fluid and an outlet circular tube (11) for flowing out the hydraulic fluid; the inlet circular tube (1) and the outlet circular tube (11) partially extend into an attenuator cavity; the upper part and the lower part of the inner surface of the cavity are respectively provided with PVDF (polyvinylidene fluoride) piezoelectric films; and outgoing lines for guiding two surfaces of each PVDF piezoelectric film out of the sealing cavity to form electrical connection with the outer part are arranged on each PVDF piezoelectric film. The hydraulic pipeline fluid pulsation attenuation device utilizes active filtering to attenuate low-frequency pulsation and utilizes passive filtering to attenuate medium-high-frequency pulsation; the active filtering and the passive filtering are combined, so that the original dynamic characteristic of a hydraulic system can be kept, and pulsation attenuation effect can be improved within a relatively wide frequency band.

The invention relates to a direct current stabilized current power supply which realizes low ripple by IGBT series-parallel connection, and the invention belongs to the field of automatic control technology and power electronic technology and relates to a power change circuit based on a large capacity IGBT apparatus. The power change circuit comprises an incoming filter circuit, a phase shifting circuit, an input end rectification filter circuit, an energy storage circuit, a front reduction voltage chopper circuit, a front passive filter circuit, a back reduction voltage chopper circuit, a back passive filter circuit, an output end passive filter circuit, a voltage sensor circuit, a current sensor circuit and a control circuit used for controlling a whole circuit to work. Water cooling or forced air cooling can be applied to the direct current stabilized current power supply, and the direct current stabilized current power supply has the advantages that the power supply has high stability of current in a long term, low voltage (current) ripple, fast response, high regulation precision, small size, high efficiency and small noise of a device.

The invention discloses a high voltage filter and dynamic reactive power compensation control system combining a PPF with a TSC and a control method thereof, belonging to the technical field of power electronics. The invention solves the problems that a traditional independent PPF technology has reactive power compensation reactive power over compensation, and an independent TSC technology adopts classification switching and is not adapted to reactive power continuous variation of a power grid. In a device thereof, a passive filtering unit and a reactive power dynamic compensation unit are in parallel connected between the input end and the load end of the power grid, a signal conditioning circuit is used for detecting three-phase current and voltage signals of the power grid, the output end of the signal conditioning circuit is connected with the input end of a DSP (Digital Signal Processing) and CPLD (Complex Programmable Logic Device) control circuit, the output end of the DSP and CPLD control circuit is connected with a level conversion circuit, and the output end of the level conversion circuit is connected with a control signal input end of the reactive power dynamic compensation unit. In the method, a reactive power compensation capacitor is controlled to be thrown into the power grid according to the position of obtained power grid parameters in a space nine zone. The invention is used for reactive power compensation of the power grid.

The invention discloses an active tuning type hybrid filter, which is characterized in that the output of an APF (active power filter) is directly connected with two ends of a filter reactor L of a PPF (passive power filter) in parallel (or by a coupling transformer in parallel). The invention also discloses a control method of active tuning, which comprises the following steps by using the hybrid filter: connecting a branch with a linear load required to filter in parallel; obtaining each single harmonic current component to be filtered by detecting a harmonic current; comparing a condenser voltage with a reactor voltage and then carrying out PI adjustment so as to obtain the detuning degree under the condition of the frequency of harmonic to be filtered; generating the detuning degree into a harmonic compensating current weighting coefficient; forming a harmonic compensating current command; generating an active current command of fundamental waves; summing to obtain a command current of the APF; and generating a PWM (pulse-width modulation) drive signal after the command current and an actually-output current signal are subjected to PWM generation and drive. The method is remarkable, safe and reliable.

The invention discloses a hybrid active power filter and an SVPWM (Space Vector Pulse Width Modulation) method based on the filter. The hybrid active power filter comprises an active power filter (APF), single-tuned passive filters (PPFs) and an isolation transformator, wherein an inverter of the active power filter adopts a three-phase four-switch structure; four IGBT (Insulated-Gate Bipolar Transistor) devices form two bridge arms; a capacitor on the DC side forms a third bridge arm; the output terminal of the active power filter is connected with the secondary side of the isolation transformator; the secondary side of the isolation transformator is connected in parallel with a fundamental shunt inductor; and the primary side of the isolation transformator is connected in series with the seventh single-tuned passive filter and connected to a power grid after being connected in parallel with a non-linear load. According to the invention, the passive filters are used to filter the fifth, the seventh and eleventh major character harmonics caused by the non-linear load, meanwhile, a certain of reactive power is compensated, and branch circuits of the active power filter dynamically control the residual harmonics in real time.

The invention discloses an active filter and a method for eliminating the secondary resonance of a train DC bus bar. The active filter comprises a bi-directional DC / DC converter with a step-up and step-down voltage function, a filter inductor and an energy storage capacitor. According to the principle of power balance, when the secondary ripple of bus voltage is fully compensated, the secondary ripple power of single-phase rectifier should be controlled equal to the secondary ripple power compensated by active power filter, and the direction is opposite. According to the voltage, current and other electrical quantities detected by the actual system, the closed-loop control is carried out, which ensures the compensation effect and the dynamic response ability of the system when the train isrunning, and improves the stability of the system. It can replace the traditional passive LC filter, can overcome the shortcoming that the passive filter can only compensate the harmonics of fixed frequency, can adapt to the complex power network environment, and the effect is more ideal than the traditional method. The device can reduce the volume and weight of the traction drive system, reducethe cost and increase the power density of the converter.

The invention discloses a reactive compensation system of a thyristor controlled magnetically controlled reactor, comprising an automatic control system, a magnetically controlled reactor and filter equipment, wherein the automatic control system is electrically connected with the magnetically controlled reactor; the filter equipment is composed of a plurality of reactive filter circuit branches; and the magnetically controlled reactor and the filter equipment are connected on three-phase alternating current in parallel. The system is characterized in that the reactive filter circuit branches are composed of filter capacitors and filter reactors which are mutually connected in series. According to reactive power sampling carried out on the grid system by a voltage sampling circuit and a current sampling circuit in the automatic control system, the signal is sent to a controller and the controller automatically adjusts the thyristor control angle of the magnetically controlled reactor to change the winding DC and control core saturation and realizes continuous adjustment of the reactance, thus realizing fast reactive power compensation. The system can quickly track reactive fluctuation of the grid or load and carry out random real-time compensation to maintain voltage stability.

An optical device (D) is dedicated to the transformation of the propagation mode of optical signals. This device comprises at least a first mode converter (3) that is supplied with signals that are propagated in a first guided mode and that delivers the signals in a multimode fibre (4) partly in the first guided mode and partly in a second guided more of a higher order that the first. The multimode fibre (4) comprises at least first passive filtering means (R) which have the task of converting the first guided mode into at least one dissipative cladding mode in order to prevent or limit the propagation of the signals in this first guided mode while at the same time authorising the propagation of the signals having the second guided mode in the multimode fibre (4).

The invention relates to a mixed active power filter based on an ip-iq detection method and hysteresis control. The mixed active power filter comprises an ip-iq harmonic current detection circuit, a hysteresis control circuit, a PF (passive filter) circuit, an APF (active power filter) circuit, a coupling transformer circuit and the like. The ip-iq harmonic current detection circuit detects harmonic current of instantaneous current of each phase in a three-phase circuit, the detected harmonic current is inputted into the hysteresis control circuit to generate a hysteresis control signal, the hysteresis control circuit automatically adjusts a hysteresis width to fix switching frequency, the hysteresis control signal is inputted into the APF circuit to generate compensating current for counteracting the harmonic current, and the APF circuit is serially connected with one branch of the PF circuit and then connected into the coupling transformer circuit. The harmonic current in the harmonic three-phase circuit is effectively filtered out by combining functional advantages of an APF and the PF, performance is improved, and the total cost of the filter is reduced.

An integrated reception system for use in a mobile phone for receiving FM / digital broadcast signals. The reception system, which is installed within the phone body, includes a substrate, an antenna having a meandering pattern disposed on the substrate for receiving the broadcast signals, and a pre-processing module disposed on the substrate and connected to the antenna for pre-processing the received signals. The pre-processing module may include a passive filtering network for band-tuning, and an active amplifier for amplifying the received signals from the antenna. The mobile phone has components for converting the received signals into audio signals to produce audio sound.

The invention relates to a method for the comprehensive control of passive filter and reactive power compensation, which comprises: firstly, judging locking conditions including total distortion and default phase of a harmonic current and voltage threshold crossing, and locking a feed outlet and switching to a protective flow when any condition is met; and when no locking condition is met, entering a control policy selection flow, wherein the policy selection is performed mainly for judging if a potential maximum subharmonic exceeds a standard, switching is performed according to a reactive power compensation policy if the potential maximum subharmonic does not exceed the standard, and control is performed according to a filter wave if the potential maximum subharmonic exceeds the standard. In the invention, through the dual control of the reactive power compensation and the filter, a power system can output at a maximum power and the production benefits are increased; and a locking protection function is provided, so the safe and reliable operation of the system are further ensured.

Systems and methods of the present disclosure involve passive, hybrid, and active filtering configurations to mitigate current harmonics for various electrical loads. One hybrid filtering configuration is medium voltage (MV) active filtering using a DC-DC converter and a multi-level inverter, and low voltage (LV) passive filtering. Another hybrid filtering configuration is MV passive filtering and LV active filtering using a two-level inverter. An active filtering configuration includes both MV and LV active filtering. The present disclosure also features power distribution unit (PDU) transformers electrically coupled to respective power supplies on the LV side of an electrical system. Each PDU transformer includes primary coils in a delta configuration and secondary coils in a wye configuration. The secondary coils are in series with respective leakage inductance coils. The secondary coils and the leakage inductance coils are integrated together into a single unit or module.

The invention relates to the technical field of optical fiber communication, specifically relates to a laser. The laser comprises an N type electrode, a substrate, a lower limiting layer and a lower waveguide layer which are arranged from the bottom up in sequence; a first active waveguide region, a second passive filtering waveguide region and a third passive coupled waveguide region which are separated mutually are arranged above the lower waveguide layer; a quantum well layer is arranged in the first active waveguide region; a one-order grating is arranged on the quantum well layer; a P type electrode is arranged on the top of the first active waveguide region; a grating material layer is arranged in the second passive filtering waveguide region; a P type electrode is arranged on the top of the second passive filtering waveguide region; a two-order grating is arranged in the third passive coupled waveguide region; and a light beam generated by exciting the quantum well layer passesthrough the one-order grating, the grating material layer and the two-order grating in sequence to be output from the top of the third passive coupled waveguide region. The laser is very simple in assembling process, the manufacturing cost of a device is lowered effectively, the overall stability of the device is improved, and the packaged dimension is reduced.

The invention discloses a serial hybrid active filter including a harmonic absorber. The serial hybrid active filter comprises an active filter unit and a passive filter unit, wherein the active filter unit comprises a transformer, an inverter and a detection control unit; a primary side AX of the transformer is connected in series to a power grid; a secondary side of the transformer is connected with the inverter; the detection control unit is used for detecting a voltage or current signal of the primary side, and driving and controlling the on / off of a switch tube of the inverter to generate a voltage or current to be applied to the secondary side of the transformer, so that the primary side AX of the transformer presents low impedance to fundamental waves and presents high impedance to harmonic waves; and the passive filter unit comprises LC series-parallel branches which are connected in parallel to two ends of a harmonic source load. During working, the active filter unit presents low impedance to the fundamental waves and presents high impedance to high-order harmonic waves. A serial part of the passive filter unit generates series resonance at m-order harmonic frequency, and absorbs m-order harmonic current, so that the harmonic waves flow through the passive filter unit instead of flowing into the power grid, and a function of filtering the harmonic waves is realized.

The invention discloses a transformerless hybrid active power amplifier and implementation and control methods thereof. The transformerless hybrid active power amplifier comprises a double-turned passive filter and a diode-clamped active filter. The diode-clamped active filter is a tri-level inverter. The double-turned passive filter comprises three passive filter branches connected with phases A, B and C of a power grid respectively. Each passive filter branch comprises an impregnated capacitor (C1), a divider capacitor (C2), a parallel capacitor (C3), a first inductor (L1) and a second inductor (L2). Impregnation points of the three passive filter branches are connected with three terminals on the alternating-current side of the tri-level inverter through three output inductors (L) respectively. The transformerless hybrid active power amplifier features both low cost of a PPF (passive power filter) and excellent filtering and dynamic performance of an APF (active power filter), is easy to implement and is effective in filtering.

The invention discloses a hybrid power filter main circuit which comprises a passive filter circuit, an active filter circuit and a measuring circuit, wherein the passive filter circuit consists of a double-tuned filter branch circuit and a base-wave partial-pressure series double-tuned filter branch circuit; a resonance point of one double-tuned filter branch circuit is set to be three times or five times, and a resonance point of the other branch circuit is set to be five times or seven times; the passive filter circuit is directly connected with the active filter circuit by a circuit instead of a coupling transformer; and the measuring circuit comprises a voltage sensor B1 at a power grid side, a load current sensor B2 at the power grid side, a passive filter branch circuit current sensor B5 in a passive filter branch circuit, a voltage sensor B5 at an active and passive connecting point, a compensating current sensor B4 in the active filter circuit, and a direct current (DC) bus voltage sensor V1. Due to the structure without the coupling transformer, the cost and the size of a system are obviously reduced, the defect of compensating current phase delay caused by the coupling transformer can be overcome, and the compensation precision is improved.

The invention relates to an accelerator beam position diagnosis system and an accelerator beam position diagnosis method based on eight-octant probe distribution. The system comprises a three-dimensional eight-octant interception-type probe distribution mechanism, a multi-range passive filter signal conditioning module, a beam signal amplifying module, a beam signal photoelectric isolation module, a beam signal acquisition module, a beam position automatic diagnosis module and an intelligent configuration decision supporting system. When a particle accelerator operates, the eight-octant probes distributed on the wall of a vacuum pipeline collect beam signals coupled by charges incident to the sensitive ends by the beam, the position automatic diagnosis module in the controller calculates the position information of the beam in real time according to eight-octant voltage signals acquired by the signal acquisition module, the operation result is transmitted to the intelligent configuration decision supporting system of an operation station, a three-dimensional animation is adopted to prompt the operator whether the beam biases and the beam adjustment strategy. Through the intelligent and visual diagnosis strategy, the accuracy, the real-time performance and the usability of the accelerator beam position measurement system are effectively improved.

The invention discloses a power inductive filtering system and a virtual impedance comprehensive control method therefor. The power inductive filtering system mainly comprises a novel inductive filtering transformer subjected to special design and a filtering branch connected with the novel inductive filtering transformer, wherein the filtering branch comprises a single tuned filter set and harmonic current controlled voltage source inverters connected in series. According to the power inductive filtering system and the virtual impedance comprehensive control method, power grid resonance damping control of the voltage source inverters is organically combined with zero impedance control of filters according to unsolved technical problems in an existing filtering method and existing device manufacturing process difficulties, so that the problem of performance reduction of a passive filtering device caused by impedance parameter change of a power grid system is solved on one hand and the optimization control of a quality factor of the passive filtering device can be realized for reducing the dependence on the level of a device production process on the other hand; and quality factors of the single tuned filters are enabled to meet design requirements, so that the overall filtering characteristics are further improved.

A hybrid filtering compensation device is characterized in that a grid-side signal acquisition module sends a signal detected on a current-voltage transformer CT1 on the grid side to a passive filtering compensation module, a shunt reactor L outputs inductive reactive power for compensating the capacitive reactive power generated by a filtering compensation branch; a load-side signal acquisition module sends a signal detected by a current-voltage transformer CT2 on the load side to an active filtering module; a knife switch QK is connected with a busbar between the grid side and the load side; The wire output end of the knife switch QK is connected with three fuses; the three fuses are connected with the shunt reactor L, the passive filtering compensation module, the active filtering module, and a touch screen controller; a circuit breaker QF1 is installed between a power main circuit and the wire input end of the passive filtering compensation module, and the touch screen controller is connected with the passive filtering compensation module and the active filtering module through a 485 communication bus.

The invention provides a fundamental wave magnetic flux tuning passive filter and harmonic extraction device which comprises an alternating-current power supply, a harmonic filtering and extraction unit and a load harmonic source, wherein the alternating-current power supply is used for transmitting a generated fundamental wave signal to the harmonic filtering and extraction unit; the harmonic filtering and extraction unit is used for transmitting the fundamental wave signal to the load harmonic source in a tuning manner without attenuation; meanwhile, an extracted harmonic signal is subjected to harmonic rectification and filtering treatment in a tuning manner to obtain a direct-current signal; the load harmonic source is used for providing the fundamental wave signal subjected to harmonic source rectification to a load; and meanwhile, the generated harmonic wave signal is returned to the harmonic filtering and extraction unit. The fundamental wave magnetic flux tuning passive filter and harmonic extraction device has the characteristics of simple structure, better harmonic filtering effect, energy conservation and the like and can be widely applied to the field of accurate equipment control.

Embodiments of the present invention relate generally to reconstruction filtering. In particular, embodiments enable highly linear, highly programmable, and easily reconfigurable reconstruction filters. Further, embodiments provide substantial power consumption, area, and cost savings compared to conventional solutions. For example, embodiments use all-passive filtering and substantially reduce active elements compared to conventional solutions. As a result, significant reductions in required area, noise, and power consumption can be achieved. In addition, embodiments perform filtering solely in the current domain, thereby eliminating the non-linear voltage-to-current conversion used in conventional circuits and enabling highly linear filtering. Furthermore, embodiments are highly programmable and easily reconfigurable without the use of tunable capacitors. As such, embodiments are very suitable solutions for multi-band multi-mode wireless transmitters.

In one embodiment, the present invention is directed to an apparatus configured to perform channel filtering operations digitally, to reduce area and power consumption as compared to analog filtering. After passive filtering of downconverted analog baseband signals, the signals are provided to digitization circuitry to convert the filtered baseband signals into digital signals. Then a digital circuit, which may be implemented as a digital signal processor (DSP), may channel filter the digital signals and provide the filtered digital signals to conversion circuitry to convert the channel filtered digital signals back to analog signals.