1547 results about "Filter capacitor" patented technology

The invention relates to the technical field of semiconductor laser power supplies, in particular to a semiconductor laser power supply control circuit based on linear constant current and a method thereof. According to the technical scheme, the circuit comprises a voltage follower module, a linear constant-current driving module, a power switch module, a pulse control module, a sampling feedback module and a follow current protection unit. The in-phase input end of an operational amplifier OPA320 of the voltage follower module is connected with external reference voltage # imgabs0 #, the inverted input end of the operational amplifier OPA320 is grounded through a first resistor R1 and connected with the output end through a second resistor R2, and a filter capacitor C1 is connected to the two ends of the second resistor R2 in parallel. Through a linear constant current control and pulse cooperation mechanism, the current stability and the dynamic response speed of the semiconductor laser under the wide-range and high-frequency working condition are remarkably improved, and it is guaranteed that the laser output power is accurate and reliable.

The power conversion device provided by the invention comprises a direct current end, a positive direct current bus, a negative direct current bus, a positive bus capacitor, a negative bus capacitor, at least three inverter bridge arms, a switch unit, a controller, filter inductors corresponding to the at least three inverter bridge arms one by one, a filter capacitor and an alternating current end. And the third end of each inverter bridge arm sequentially passes through the filter inductor, the filter capacitor and the switch unit corresponding to each inverter bridge arm and then is connected with the midpoint of the bus. The controller controls the switch unit to be switched off or the impedance of the switch unit to be increased when the voltage of the power grid is smaller than or equal to a first voltage threshold value; and after the switch unit is switched off or the impedance of the switch unit is increased, the modulation wave of each inverter bridge arm is controlled to be the modulation wave after the first common-mode modulation signal is superposed on the initial modulation wave of each inverter bridge arm, so that the amplitude of the modulation wave of each inverter bridge arm is increased. Furthermore, not only can the loss of the switching tube in each inverter bridge arm be balanced, but also the problem of common-mode oscillation caused by modulation wave change can be improved.

The invention discloses a single-load wireless power transmission system with single transmitting and double receiving coils and a method thereof. The system comprises a direct-current power supply, a high-frequency inverter, a transmitting end compensation topology module, a transmitting coil module, two receiving coil modules, two receiving end compensation topology modules, a rectifier module, a filter capacitor and a system load module. The topological structure adopts S-LC and S-LCC compensation topology, and a topological structure parameter optimization method is provided, so that the anti-offset characteristic of the system is effectively improved. The optimized system can realize the stability of the output power of the system under the working conditions of offset and load change within a certain range. According to the system, the cost of the system is reduced, the high anti-offset capability can be achieved, the output power is stable, and the overall efficiency of the system is improved.

The present invention relates to a magnetic resonance system and a gradient amplifier filter for a magnetic resonance system. The filter includes a plurality of non-magnetic core inductors and a printed circuit board having a multilayer structure, a plurality of filter capacitors being formed in a plurality of regions of the printed circuit board, respectively, wherein each non-magnetic core inductor is provided on the printed circuit board and spanning two of the plurality of filter capacitors.

The invention discloses a chip reference voltage trimming circuit which is characterized in that when an enable signal is in a high level, a low enable discharge module is turned off, and an adjustable buffer unit generates a preset voltage according to an external reference voltage and a voltage regulating signal; the generated preset voltage generates a reference voltage after passing through a low-pass filtering network consisting of a fast charging path, a slow charging path and a filtering capacitor; the abnormal state detection unit is used for detecting the abnormity of the trimming circuit, if abnormity exists, the output signal of the abnormal state detection unit is high level, the output signal of the quick charging control unit is controlled to be low level, the quick charging access is opened, and the opening time of the quick charging access is controlled through the quick charging control unit; and a following speed trimming signal is input to the fast charging control unit, and the generated reference voltage is trimmed to be the same as the preset voltage. The performance of the reference voltage of the chip is adjusted through the trimming signal, and the performance requirements of equipment in different working states can be met.

An image sensor may include an array of imaging pixels arranged in rows and columns. Each column of pixels can be coupled to a column analog-to-digital converter (ADC) via a pixel output line. The column ADC can include a first low noise single-ended comparison stage, a second low noise single-ended comparison stage, a latch circuit, and a counter. The first low noise single-ended comparison stage may include one or more current source transistors, a voltage ramp generator, a common source amplifier transistor, one or more autozero components, one or more capacitors such as a noise filtering capacitor, and a voltage clamping circuit. The voltage ramp generator can output an increasing voltage ramp or a decreasing voltage ramp.

The static synchronous phase modifier comprises a DC / AC converter and a controller, the direct current side of the DC / AC converter is connected with an energy storage unit composed of the hybrid supercapacitor, and the alternating current side of the DC / AC converter is provided with an LC filter circuit; the controller adopts a virtual synchronous machine control technology to control the DC / AC converter, and comprises a power calculation part, an active power control part and a reactive power control part; the power calculation part is used for calculating actual active power and actual reactive power according to the current of the filter inductor, the voltage of the filter capacitor and the line current; the active power control part performs active power control according to the actual active power and the reference active power; the reactive power control part performs reactive power control according to the actual reactive power and the reference reactive power. According to the invention, frequency and voltage support can be provided when a short-circuit fault occurs in the line, frequency collapse is prevented, the low-voltage ride-through success rate of the wind turbine generator is improved, and the grid-connected strength is improved.

The utility model discloses a low power consumption circuit and a refrigerator. The low power consumption circuit comprises a main control circuit; the power supply circuit comprises a live wire terminal, a zero line terminal, a filter capacitor and a rectifying circuit; the discharging circuit comprises a switching circuit, an optocoupler bidirectional silicon controlled rectifier and a discharging resistor; a switching path of the switching circuit is connected in series in a power supply loop of a light-emitting end of the optocoupler bidirectional silicon controlled rectifier, one end of a light-receiving end of the optocoupler bidirectional silicon controlled rectifier is connected with one end of the filter capacitor, and the other end is connected with the other end of the filter capacitor through the discharge resistor; and the voltage detection circuit is used for detecting the AC voltage and outputting a detection signal to the main control circuit, and the main control circuit controls the on-off of the switching circuit according to the received detection signal. According to the low-power-consumption circuit and the refrigerator provided by the utility model, when alternating current is normally supplied, the discharge resistor does not generate power consumption; when the alternating current is cut off, the discharge resistor discharges through the optocoupler bidirectional silicon controlled rectifier, and the technical problem of high power consumption of the discharge resistor during normal power supply in the prior art is solved.

The invention discloses a CPT wireless energy transmission higher harmonic filter and a CPT wireless energy transmission system based on the same, and relates to the technical field of wireless power transmission. Comprising more than one harmonic filter circuit, wherein the CPT wireless energy transfer higher harmonic filter is connected between a CPT wireless energy transfer Class EF inverter and a CPT wireless energy transfer transmitting terminal compensation network; each harmonic filter circuit comprises a filter inductor and a filter capacitor; one end of the filter inductor is connected with a drain electrode of an MOS (Metal Oxide Semiconductor) tube in the CPT wireless energy transfer Class EF inverter and an input end of the CPT wireless energy transfer transmitting end compensation network; the other end of the filter inductor is connected with one end of the filter capacitor, and the other end of the filter capacitor is grounded. According to the invention, the harmonic suppression capability can be improved, the size of filter elements is reduced, the stability of resonant frequency is enhanced, and the design and debugging process is simplified.

The invention discloses an isolation type split-phase inverter circuit and a control method thereof. The isolation type split-phase inverter circuit comprises an isolation DC / DC module circuit and a power frequency rectification module circuit. The isolation DC / DC module circuit comprises an input-side full bridge, a three-end transformer and two output-side circuits, an input-side winding of the three-end transformer is connected with a midpoint of a bridge arm of the input-side full bridge, and the input-side full bridge is connected with a filter capacitor C1 in parallel; two output side windings of the three-end transformer are respectively connected with corresponding output circuits through a resonance network circuit, the two output circuits are connected to a power frequency rectification module circuit through filter capacitors C4 and C5, and the negative electrode of the first output circuit and the positive electrode of the second output circuit are connected to form an interface N; the power frequency rectification module circuit comprises a rectification full-bridge circuit, and an interface L1 and an interface L2 are obtained after rectification. Through cooperative control of direct transmission of integrated topology and voltage signals, a complex parameter matching algorithm is not needed, breakthrough in structure simplification, energy conversion efficiency, control convenience, cost control and safety is achieved, and the method is suitable for various power conversion scenes.

The invention provides an arc voltage sampling circuit and method suitable for a welding power source. The arc voltage sampling circuit comprises an anti-interference absorption unit, a sampling conditioning unit and an isolation conversion unit. The anti-interference absorption unit is electrically connected to the output end of the welding power source so as to collect arc voltage signals. The anti-interference absorption unit comprises two common-mode absorption capacitor banks connected between a positive bus and a negative bus in series, and the middle point of the two common-mode absorption capacitor banks is electrically connected to the ground. The sampling conditioning unit comprises a sampling network and a filter capacitor, the sampling network comprises a plurality of divider resistors connected in series between positive and negative buses, the filter capacitor is connected in parallel with the output of the sampling network, and at least one stage of RC filter is formed between the filter capacitor and the divider resistors in the sampling network. The isolation conversion unit comprises an optical coupling isolator and a conversion circuit. The optical coupling isolator isolates the arc voltage sampling signal and converts the arc voltage sampling signal into a switching value signal or an analog quantity signal with various output amplitudes based on the conversion circuit.

The invention discloses an isolation circuit, a three-phase isolation circuit, a controller, a method and a storage medium, and the isolation circuit comprises an input filter capacitor (Ci), a first inductor (Lf1), a second inductor (Lf2), an upper tube (Q1), a lower tube (Q2), a first energy transfer capacitor (C1), a second energy transfer capacitor (C2), a first transformer (T1) and a second transformer (T2). Meanwhile, a single-stage isolation topology control algorithm is simplified, the conversion efficiency is greatly improved, the requirements of higher power level design and wider output voltage range can be met, and higher input voltage working capacity can be achieved; the electromagnetic compatibility of the power supply module can be greatly improved due to the double-inductor design of input energy transfer; furthermore, an active power factor calibration function can be realized, and input and output current ripples and voltage ripples can be greatly reduced through upper and lower tube staggered phase-shifting control, so that the service life of an output capacitor is prolonged.

Techniques for controlling a low-dropout (LDO) voltage regulator. In an example, an LDO voltage regulator circuit includes an amplifier having an output coupled to a transistor. First and second inputs of the amplifier are coupled to a power supply node via first and second resistors, respectively. The transistor gate is coupled to the amplifier output, the transistor source is coupled to the second input of the amplifier, and the transistor drain is coupled to a reference voltage node. The second resistor is variable based on the amplifier output and a reference voltage from the reference voltage node. In an example, the reference voltage node is connectable to ground via a reference resistor connected in parallel with a noise-filtering capacitor, which causes a reference current to flow through the transistor. The reference current is adjusted based on the drain-to-source voltage of the transistor.

The invention discloses a control method and device for switching grid connection to grid disconnection of an energy storage system. The control method comprises the following steps: acquiring a phase voltage and a bus voltage on a line when the energy storage system is controlled to be switched to an off-grid state; determining the maximum open-loop duty ratio according to the phase voltage and the bus voltage; within preset time, the energy storage system is controlled to be in an open-loop driving state, and the duty ratio of a driving signal sent to the energy storage inverter is controlled to be monotonically decreased from the maximum open-loop duty ratio, so that the voltage output by the energy storage inverter is controlled to be gradually decreased to be close to zero, therefore, the voltage output by the energy storage inverter and the voltage on the filter capacitor connected with the output side of the energy storage inverter are not opposite in phase, the oscillation of the output voltage is avoided, the impact current of the output port is suppressed, and the stable operation of the energy storage inverter of the energy storage system is ensured.

The invention discloses a modular neutral-point-clamped three-level inverter zero-sequence circulating current suppression method, and relates to the field of electrical engineering, and the method comprises the steps: building a zero-sequence circulating current mathematical model of a modular neutral-point-clamped three-level inverter parallel system based on the Kirchhoff voltage and current law; on the basis of the mathematical model, combining with the Thevenin equivalent law, simplifying an original circuit, establishing an equivalent zero-sequence circulating current circuit model, and in the zero-sequence circulating current circuit model, providing a low-impedance bypass for the high-frequency zero-sequence circulating current through a filter capacitor branch, and shunting the high-frequency zero-sequence circulating current; an LCL filter structure is optimized through a scheme that modules share a filter capacitor, so that a plurality of inverter modules share one filter capacitor, the consumption of the filter capacitor is reduced, and current ripples on a connecting cable are reduced; a switch ripple phase shift regulation strategy is implemented, phases of switch signals are staggered among different inverter modules, and automatic offset of high-frequency switch ripples on a module shared filter capacitor is realized.

A self-centering washer is positioned between a feedthrough and a filter circuit board. The washer has openings through which first and second terminal pins extend. A first opening has an inner arcuate portion contacting the first terminal pin and an outer perimeter portion exposing the braze sealing the terminal pin to the insulator. A second opening has an inner arcuate portion contacting the second terminal pin and an outer perimeter portion exposing the braze sealing the terminal pin to the insulator. In an imaginary configuration with the first and second washer openings superimposed one on top of the other, the cumulative arcuate distance of the inner arcuate portions about one of the terminal pins, subtracting overlap, results in a gap between the superimposed washer openings that is less than a diameter of the first and second terminal pins so that the washer is prevented from lateral movement.

The utility model discloses a lightning stroke protection circuit of an electromagnetic heating device, which comprises an over-current, over-voltage and interference suppression circuit, a rectification filter circuit and a resonance heating circuit which are connected in sequence, the over-current, over-voltage and interference suppression circuit comprises a fuse FS01, a piezoresistor RZ01, a piezoresistor RZ02, a filter capacitor CX01 and a filter inductor L1, wherein the AC-L of the alternating current is sequentially connected with the fuse FS01 and the piezoresistor RZ01 in series to return to the AC-N, the AC-L of the alternating current is connected with the filter inductor L01 and the piezoresistor RZ02 in series to return to the AC-N, and the filter capacitor CX01 is connected with the piezoresistor RZ02 in parallel; the resonance heating circuit comprises a wire coil, a resonance capacitor CXZ30, an IGBT 30 and a TVS tube group. According to the utility model, two groups of piezoresistors are adopted in the overcurrent, overvoltage and interference suppression circuit, and a filter inductor is arranged in front, so that the protection response speed is improved, the effects of reducing voltage and clamping high voltage are achieved, the lightning stroke protection on a bridge rectifier is improved, and the IGBT of the resonance heating circuit is connected in parallel with a TVS tube group, so that the lightning stroke protection on the IGBT is improved, and the service life of the resonance heating circuit is prolonged. Therefore, the overall lightning protection of the electromagnetic heating device is improved.

The invention discloses a common-mode electromagnetic interference modeling and suppression method for a matrix converter, and the method comprehensively considers high-frequency parameters and topological characteristics, builds a conduction CM EMI equivalent circuit model of the matrix converter, completes the impedance network fitting of key elements and the extraction of high-frequency parasitic parameters, and achieves the modeling and suppression of the common-mode electromagnetic interference of the matrix converter. The precision of the CM EMI model of the matrix converter is improved, and the analysis of the CM EMI characteristics of the matrix converter is simplified. According to the common-mode electromagnetic interference suppression method for the matrix converter, CM EMI characteristics of the matrix converter are analyzed, a low-attenuation loop in the converter is constructed by adopting a method of combining a neutral line leading-back type structure and increasing output filter capacitor neutral-point-to-ground parasitic capacitance, the propagation proportion of noise in a linear impedance stabilization network measurement branch is reduced, and the measurement accuracy of the common-mode electromagnetic interference suppression method for the matrix converter is improved. And effective suppression of low-cost CM EMI noise is realized on the premise of not depending on an input EMI filter.

The invention provides a high-power filter based on fractional order positive and negative inductor parallel connection and a control method, and the filter comprises a fractional order negative inductor # imgabs0 # and a positive inductor # imgabs1 # which are connected in parallel. The fractional order negative inductor # imgabs2 comprises a first switch tube V1, a second switch tube V2, a third switch tube V3, a fourth switch tube V4, filter inductors L1 and L2, a filter capacitor Cf, a filter damper Rf, a grounding capacitor Cg, a sampling resistor R, a DC-DC conversion circuit, a self-powered module, an MCU controller, a digital-to-analog converter AD and a sine pulse width modulation module SPWM. According to the scheme, the inductance value and the order of the fractional-order inductor can be changed at will by changing the parameters of the MCU controller, so that the inductance value of the high-power filter with the fractional-order positive and negative inductors connected in parallel is changed, and low cost, small size, high power density and flexible and adjustable order and inductance value of the filter inductor are realized; and the method can be applied to a high-power scene with relatively high harmonic content, and a better filtering effect is achieved.

The invention discloses a direct-current filter capacitor applied to the aviation field, and the capacitor upper and lower cover conductive copper bar group adopts a composite copper bar structure of which the upper and lower covers are mutually closed, and the capacitor upper cover conductive copper bar group is provided with an upper cover conductive copper bar group and a copper upper cover structure which is downwards and vertically turned over; the capacitor lower cover conductive copper bar group is provided with a lower cover conductive copper bar group and a copper lower cover structure which is upwards and vertically turned over, the capacitor packaging shell is provided with a bottom shell and a shell side wall structure which is upwards and vertically turned over from the periphery of the bottom shell, and the capacitor inner core group is distributed in a closed cover cavity which is formed after the upper part and the lower part of the closed cover cavity are mutually closed; the whole interior of the closed cover cavity is of a cylindrical cavity structure, the closed capacitor upper cover conductive copper bar set and the closed capacitor lower cover conductive copper bar set are provided with capacitor leading-out positive and negative electrode conductive copper bar sets which are led out upwards, and capacitor positive and negative electrode leading-out end insulation blocks are arranged outside a bottom shell of the capacitor packaging shell. The special strict requirements of high stability and reliability of electric work, long service life, low aging rate and the like are better met, and the service life safety is improved.

A method for detecting an insulation fault of an electric battery. The method includes acquiring an insulation resistance value from a detection device, the detection device being connected to an electrical accumulator battery terminal and to ground, and including, in series, a current-limiting resistor, a filtering resistor and a voltage source, and a filtering capacitor in parallel with said filtering resistor. The method further includes a series of steps of optimizing the switching period of the switch of the device for detecting the insulation resistance value.

The utility model discloses an anti-thunder filtering electric connector, which comprises a metal shell, an input end contact element, a filtering capacitor, an output end lead, a transient suppression diode and a printed board, and is characterized in that the filtering capacitor is a plate-type capacitor which is arranged in the metal shell; the plurality of input end contacts respectively pass through a plurality of inner electrode through holes of the plate-type capacitor and a plurality of corresponding through holes on the printed board, the plurality of transient suppression diodes are respectively installed on the printed board, and one ends of the transient suppression diodes are respectively in conductive connection with the plurality of input end contacts. The other ends of the plurality of transient suppression diodes are respectively and conductively connected with the inner wall of the metal shell, and the inner ends of the plurality of input end contacts are respectively and conductively connected with the inner ends of the plurality of output end leads. The utility model has the functions of filtering, lightning protection and electric connection at the same time, the product integration level is very high, the volume and the weight are reduced, a lightning protection circuit module does not need to be added in a post-stage circuit module during application, the design and the production of the whole machine are facilitated, and the production efficiency of the whole machine is improved.

The invention relates to a converter soft start method based on mode seamless switching, which belongs to the technical field of converter soft start, and comprises the following steps: a converter adopts a network following / network construction hybrid control structure; after the converter receives a starting instruction, voltage and frequency are automatically constructed in a network construction control mode, and a filter capacitor is pre-charged; performing amplitude and phase angle pre-synchronization on the voltage of the output port of the converter and the voltage of the power grid based on a pre-synchronization strategy; and switching the converter from a network construction control mode to a network following control mode to complete soft start. According to the method, the pre-charging requirement of the alternating current capacitor is met, and soft-start smooth grid-connected operation of the converter is realized through a pre-synchronization strategy.

The invention provides a detection circuit, a battery pack and a battery management system. The detection circuit is used for detecting a connection circuit of a first battery in a plurality of batteries connected in series. The detection circuit comprises a self-checking resistor; the equalization circuit comprises an equalization switch, and the equalization circuit is connected in series with the first battery through a self-check resistor; the filter circuit comprises a filter capacitor, and the filter circuit is connected with the equalization circuit in parallel; the sampling chip is connected with the two ends of the filter capacitor, the sampling chip, the filter circuit and the self-checking resistor jointly form a sampling circuit of the first battery, the sampling chip is used for determining whether the sampling circuit of the first battery fails or not according to a first voltage and a second voltage, the first voltage is the voltage on the filter capacitor when the equalization switch is switched off, and the second voltage is the voltage on the filter capacitor when the equalization switch is switched off; and the second voltage is the voltage on the filter capacitor when the equalization switch is closed. The detection circuit reduces the diagnosis cost and the overall size.

The invention discloses a novel chopping correlation double-sampling stable multi-path amplifying circuit and method, and relates to integrated circuit design. A Miller compensation capacitor in a chopping stable multi-path CSMP amplification circuit architecture is utilized to design a chopping correlation double-sampling circuit, and compared with a traditional correlation double-sampling circuit, a group of sampling capacitors and sampling switches are reduced. Large capacitance and large resistance required by a traditional high-pass filter circuit are eliminated, and the layout area and the current required for driving a high-pass filter capacitor are reduced; and thermal noise caused by large resistance in the passive high-pass filter is reduced, and the input equivalent noise density is improved. Through an offset calibration technology, the stability of the CSMP architecture is ensured, and the offset voltage is reduced at the same time; output ripples are suppressed by using the high-pass performance of the novel chopping correlation double-sampling circuit, 1 / f noise is reduced, and input equivalent noise density is reduced. The advantages of the chopping correlation double sampling technology and the stable multi-path amplification circuit are combined, and the advantages of low offset, low output ripple and low input equivalent noise density are achieved.

The invention relates to a compact railway energy regulation and control complex which comprises a converter unit with an intermediate frequency transformer as a core, and an alternating current port of each converter unit is connected with buses of alpha and beta phase traction feeder lines on the secondary side of a V / v traction transformer in series. A magnetic field hedging decoupling inductor and a filter capacitor of the medium-frequency transformer form a secondary harmonic filter branch on the direct current side of each converter unit, non-negligible secondary harmonic components on the direct current side of each converter unit in the single-phase converter system are filtered out, and a power winding of the medium-frequency transformer is connected with a DC / DC converter on the inner side of each converter unit. The compact railway energy regulation and control complex can accurately control the tidal current distribution of the two power supply arms, carries out comprehensive energy regulation and control through a direct current port and an external energy storage and new energy power generation system, can effectively inhibit the voltage fluctuation of a feeder line side, improves the comprehensive energy utilization rate and the new energy consumption rate of an electric railway system, and improves the energy utilization rate of the electric railway system. Compensating the power factor of the high-voltage side of the transformer substation and inhibiting the voltage unbalance degree of the PCC point.

The invention discloses an integrated three-phase Boost-LLC topology and a modulation method. The integrated three-phase Boost-LLC topology comprises a transformer, a primary side circuit and a secondary side circuit, wherein the primary side circuit and the secondary side circuit are connected to the two sides of the transformer; the primary side circuit comprises a preceding-stage three-phase staggered Boost circuit and a backward-stage three-phase LLC resonant circuit, the preceding-stage three-phase Boost circuit comprises six switching tubes and three choking coil inductors, the three inductors are connected between the input and the midpoint of a three-phase bridge arm, the six switching tubes are located between the positive electrode and the negative electrode of a middle bus, and the backward-stage three-phase LLC resonant circuit is located between the positive electrode and the negative electrode of the middle bus. Meanwhile, the six switching tubes are multiplexed to serve as inversion bridge arms of a post-stage three-phase LLC, and the post-stage LLC resonant circuit is connected behind the three-phase bridge arms; the secondary side circuit comprises a three-phase rectifier bridge, is composed of six switching tubes and is connected to the secondary side of the transformer, and the direct current output is connected with an output filter capacitor and a load. According to the invention, the number of devices is reduced through bridge arm multiplexing, a wide voltage regulation range is realized, and synchronous rectification is convenient to realize.

A fault suppression control method based on a capacitive energy storage system comprises the steps that a DC / DC converter of the capacitive energy storage system is constructed, a voltage and current double-closed-loop control structure of the capacitive energy storage system in a charging mode and a discharging mode is constructed based on the DC / DC converter, and the voltage of an energy storage capacitor or a filter capacitor serves as an outer loop control variable; the current of the energy storage inductor is used as an inner loop control variable, turn-on and turn-off signals of a switching device are output through PWM modulation, and finally fault suppression control is achieved after current-limiting control parameter optimization. Energy absorption and release between the ship power system and the energy storage capacitor are realized by adopting the bidirectional DC / DC converter, fault current suppression during a fault is realized, meanwhile, the requirement on a current limiting reactor is reduced, the cost of system elements is reduced, and the influence of reactor installation on the system is avoided.

The invention relates to an internal serial metallized film, a preparation method, a filter capacitor and a base film, the base film is made of a blending material of polyethylene glycol terephthalate and polyethylene naphthalate according to a mass ratio of 2: 3, and the thickness of the base film is 8-12 [mu] m; the multi-layer metallization layer is arranged on the base film and comprises a first metal layer, a buffer layer and a second metal layer, the buffer layer is located between the first metal layer and the second metal layer, the patterned structure forms a plurality of conductive units which are connected in series on the multi-layer metallization layer, each conductive unit is in a regular hexagon shape, and the first metal layer is arranged on the first metal layer. The side length of the conductive units is 3-6mm, and an isolation belt with the width of 0.3-0.8 mm is arranged between the adjacent conductive units. According to the invention, a plurality of key performance indexes such as high-frequency filtering performance, voltage endurance capability, oxidation resistance, structural stability, light transmission and the like are optimized and improved.

The single-phase bidirectional single-stage isolation matrix converter comprises a pre-stage circuit and a post-stage circuit, and the pre-stage circuit comprises an LC filter on the power grid side, a pre-stage single-phase matrix conversion circuit and an LLC resonance circuit with a high-frequency transformer; the post-stage circuit comprises a post-stage conversion circuit and an output filter capacitor; the front-stage single-phase matrix conversion circuit comprises four bidirectional switch assemblies of a full-bridge structure. Each bidirectional switch assembly comprises two unidirectional controllable MOS tubes which are reversely connected in series, one end of each bidirectional switch assembly is connected to an L line or an N line of a power grid, and the other end of each bidirectional switch assembly is connected to the LLC resonance circuit. The rear-stage conversion circuit comprises a bidirectional MOS (Metal Oxide Semiconductor) tube bridge circuit and three high-frequency transformer secondary windings which are in triangular connection or star connection; and two end points of each secondary winding are respectively connected to the upper MOS tube and the lower MOS tube of the corresponding bridge arm and then are connected to output positive and negative ends. The converter has the advantages of high power density, low current harmonic, high power factor and the like, and is small in size, strong in anti-interference capability, wide in buck-boost range, and safe and reliable in commutation.