397results about How to "Reduce current stress" patented technology

The invention discloses a phase shift control method for a double-active full bridge bidirectional DC-DC converter in a full load range ZVS and belongs to the high frequency switching power supply inthe power electronic field. The method is characterized in that an excitation current is introduced by the converter on the basis of the original topology, the minimum current required for resonance of a secondary side switch tube when it is turned off is compensated, and thereby the soft switching range of the secondary side switch tube of the converter is expanded. In an EPS mode, based on the injected excitation current, the control strategy for the full load range ZVS and the low current stress is designed, by controlling an on-bridge duty cycle of a high voltage side and an inter-bridge phase shift angle of two full bridges, the converter can operate in the ZVS region at different voltage ratios under different transmission powers, that the converter achieves soft switching over the full load range is guaranteed, switching loss of the switch tube is reduced, moreover, the current peak is reduced, the current stress of the power device is reduced, on-state loss and loop loss of theconverter are reduced, and circuit loss is further reduced. The converter is advantaged in that efficiency and reliability can be improved.

The invention relates to an optimal current waveform controlling method for a current type two-way DC-DC convertor, and belongs to the power electronics field of the high frequency switch power source direction. According to the method, by simultaneously adjusting the duty ratio of a low voltage side and the conductive logic of two bridge arm switching tubes of a high voltage side, so that when the voltage of the low voltage side of a transformer reaches zero, a leakage inductance current of the transformer maintains the cocurrent change, the dynamic change of the leakage inductance current is completed so that the maximum peak value can be reached, when the voltage of the low voltage side of a transformer does not reach zero, the peak value of the leakage inductance current is guaranteed to be minimum under the condition of transmitting the same power. Therefore, the current-circulation loss and the conduction loss of circuits and the switching tubes and the current stress of power devices are greatly reduced, and the efficiency and performance of the circuits are improved. Meanwhile, although conducting logics of secondary side switching tubes during a boost mode and a buck mode are slightly different, the seamless switching can be achieved between the boost mode and the buck mode, so that a closed loop real-time control on the system can be easily achieved.

An organic electroluminescent display device includes a substrate, a gate line on the substrate, a data line crossing the gate line over the substrate, a switching thin film transistor near the crossing of the gate line and data line, a driving thin film transistor system including a plurality of sub-TFTs connected in parallel to the switching thin film transistor via a gate base, a power line crossing the gate line over the substrate and electrically connected with the plurality of sub-TFTs, a first electrode over the driving thin film transistor system in contact with the plurality of sub-TFTs, an organic electroluminescent layer on the first electrode, and a second electrode of transparent material on the organic electroluminescent layer.

The invention relates to a leakage inductance current slope direct control method based on an isolation type two-way three-level converter and belongs to the field of power electronics. Leakage inductance current is directly sampled at a high speed in real time to realize direct control on the leakage inductance current; even a transformer turn ratio error and circuit parasitic parameters exist, better control on leakage inductance current slope can also be realized; thus the current stress and current-circulation loss of a circuit are reduced. The low voltage side of a main circuit is formed by a current type half-bridge topology structure with an active clamping circuit; a high voltage side adopts a three-level half-bridge topology structure; a control strategy is that output voltage, input current and the leakage inductance current are sampled, operation is performed by a digital operation controller (DSP (digital signal processor)), a duty ratio and a phase shift angle are generated by a digital PI regulator, switching tubes of primary and secondary sides are controlled, the circuit power transmission direction and the leakage inductance current slope are directly controlled, and thus the less current stress and current-circulation loss and seamless switching of two-way operation of the circuit are realized.

The invention discloses a novel power electronic traction transformer topological structure and a control method thereof. A novel power electronic traction transformer comprises N power transformation units. Each power transformation unit comprises an H bridge converter and a middle/high frequency isolated-type DC/DC conversion unit. The N H bridge converters for an N-grade cascaded H bridge converter, and the middle/high frequency isolated-type DC/DC conversion unit comprises K DC/DC converters. Input ends of the N power transformation units are connected in series and output ends of the N power transformation units are connected in parallel. Input ends of the N-grade cascaded H bridge converter are connected in series, and output ends of the N-grade cascaded H bridge converter are disconnected. Input ends of the N DC/DC conversion units are connected with the output ends of the N-grade cascaded H bridge converter, and output ends of the N DC/DC conversion units are connected in parallel. Input ends of the K DC/DC converters are connected in series, and output ends of the K DC/DC converters are connected in series. The power balance control of the novel power electronic traction transformer comprises three parts: the direct current output voltage balance control of each H bridge converter, the output current balance control of each middle/high frequency isolated-type DC/DC conversion unit, and the input voltage balance control of each DC/DC converter of each middle/high frequency isolated-type DC/DC conversion unit.

The invention provides a low-power bidirectional photovoltaic storage current transformer. A grid-connected charge and discharge loop is formed by a storage battery and a two-path interleaved BUCK/BOOST circuit, a bidirectional DC/AC full-bridge circuit, a grid-connected and offline switching circuit and a power grid. The storage battery is connected with the two-path interleaved BUCK/BOOST circuit, the bidirectional DC/AC full-bridge circuit, the grid-connected and offline switching circuit and a load in turn so as to form a sensitive load power supply circuit. A solar cell panel and a photovoltaic input BOOST circuit are connected with the two-path interleaved BUCK/BOOST circuit and the storage battery in turn so as to form a photovoltaic charging circuit. The solar cell panel and the photovoltaic input BOOST circuit are connected with the bidirectional DC/AC full-bridge circuit, the grid-connected and offline switching circuit and the power grid or the load in turn so as to form a photovoltaic grid-connected and offline power generation circuit. A central control microprocessor controls the two-path interleaved BUCK/BOOST circuit, a bidirectional DC/DC full-bridge circuit, the bidirectional DC/AC full-bridge circuit, the photovoltaic input BOOST circuit and the grid-connected and offline switching circuit so that the current transformer is enabled to work under the mode of grid-connected and offline power generation or storage battery discharging or storage battery charging according to the state of the power grid, the storage battery and the solar cell panel.

The improved single stage power converter circuit topology substantially reduces EMI that is conducted to the AC line, reduces input AC current inrush, improves output ripples by the use of an auxiliary supply near zero crossings of the line AC voltage, provides Power Factors greater than 0.95, provides Total Harmonic Distortions less than 15%, and maintains constant power, including constant power in a non-linear output load. Further, this circuit topology provides output open and short circuit protections by reducing current stress in power components. This topology can also make the power source to appear as a fast-acting variable impedance source, an ideal source for powering an output load that has negative resistance characteristics such as gas discharge lamps.

The invention provides a novel resonant DC-link soft switching inverter and a modulation method thereof, and relates to the technical field of inverters. The inverter comprises an auxiliary resonant circuit, an inverter bridge, a load circuit and a DC power supply, wherein the auxiliary resonant circuit comprises a bus switch tube, two auxiliary switch tubes, two auxiliary resonant inductors, a primary resonant capacitor, two auxiliary resonant capacitors, an anti-parallel diode of the bus switch tube and four auxiliary diodes; the inverter bridge is of a three-phase bridge structure; the load circuit is a three-phase resistor-inductance load; and various main power switch tubes of the inverter bridge work in manners of sine pulse width modulation and complementary turn-on at a phase difference of 180 degrees. According to the novel resonant DC-link soft switching inverter, a zero-crossing reverse process of current of each auxiliary resonant inductor is avoided, the service life of the inverter is prolonged, and the current stress of the auxiliary switch tubes of the inverter, the conduction loss of the auxiliary resonant circuit and the switching losses of the bus switch tube and the auxiliary switch tubes are effectively reduced.

The invention discloses a current type one-way DC-DC converter and a symmetrical double PWM plus phase-shift control method for controlling the converter, relates to the current type one-way DC-DC converter and the control method, and belongs to the field of power electronics. The converter is composed of a main circuit and a control circuit. The main circuit is composed of an input side and an output side. The control circuit comprises a controller and a drive circuit. The invention also discloses the symmetrical double PWM plus phase-shift control method for controlling the current type one-way DC-DC converter. With adjustment of a phase-shift control ring between low-voltage side voltage vab and high-voltage side voltage vcd and adjustment of switching tube duty ratio through a low-voltage side PWM control ring, current stress and circulating current loss are reduced and low-ripple operation of circuit input current is realized, switching tube current stress of the input side and circulating current loss of the converter are reduced, semi-active full-bridge switching tube ZVS soft switching of the output side and diode ZCS switching are realized and efficiency and reliability of the converter are enhanced.

The present invention relates to a DC/DC converter (1) with primary side (11) consisting of a resonant converter, which DC/DC converter (1) comprises a first and a second transformer (T1, T2), connected in series on the primary side (11) and on the secondary side (12) of the DC/DC converter. The secondary side (12) comprises an autotransformer (Tcd) consisting of a first and a second winding (Tcda, Tcdb) connected to a common center tap (Tcdc), where the first winding (Tcda) of the autotransformer (Tcd) is connected to the secondary winding (T1b) of the first transformer (T1), forming a first output connection point (P1), the second winding (Tcdb) of the autotransformer (Tcd) is connected to the secondary winding (T2b) of the second transformer (T2), forming a second output connection point (P2), and the center tap (Tcdc) of the autotransformer (Tcd) is connected to the positive output (21) of the secondary side (12). The secondary side (12) also comprises a first and a second rectifying switching device (S1, S2), where the first rectifying switching device (S1) is connected between the first output connection point (P1) and the negative output (22) of the secondary side (12), and the second rectifying switching device (S2) is connected between the second output connection point (P2) and the negative output (22) of the secondary side (12). The present invention also relates to a DC/DC converter system comprising at least two inventive DC/DC converters (1).

The invention discloses a staggered parallel flyback LED driving power supply and a PFM (pulse width modulation) control circuit thereof. A main circuit of the driving power supply is formed by staggering and parallel connection of two flyback converters, and comprises an alternating-current input end, an EMI (electromagnetic interference) filter, a bridge rectifier, the two parallel flyback converters, an output rectifier and an LED load. By the aid of the staggered parallel main circuit structure, current stress of switching tubes is reduced, input and output current ripple is reduced, the EMI filter design is simplified, power level of the driving power supply is increased, and the like. A PFM control method is adopted in the control circuit of the driving power supply; compared with a common PWM control method, the PFM control method has the advantages that by the aid of the PFM control circuit, the driving power supply can change in switching tube turning-on time and switching frequency simultaneously when the load changes, working loss during light load of the driving power supply is reduced, and power supply efficiency is improved. The driving power supply is suitable for applications of an LED driving power supply with an automatic dimming function.

The invention relates to the matrix converter control technology and the high-frequency alternating-current link technology, particularly to a control method and apparatus of an AC-DC series resonance matrix converter for a high-voltage direct-current load. According to the method, a control strategy of switching of an excitation voltage from a low-wire voltage to a high-wire voltage and then to 0 voltage is used in the half period of a high-frequency current, thereby realizing three-voltage instantaneous composition; and thus the equivalent excitation voltage adjustment is realized and the average value of each phase of input wire current is in direct proportion to a phase voltage, and a high power fact and a low harmonic current are realized only by a small filtering inductance value. The provided method and the apparatus have the following beneficial effect: voltage-stabilizing outputting-based AC-DC series resonance matrix converter controlling with characteristics of high efficiency, high power factor, and low-harmonic and low-peak value current. And the method and the apparatus is especially suitable for the AC-DC series resonance matrix converter.

The present invention discloses a zero voltage zero current full-bridge DC-DC converter. Diodes are respectively and reversely connected in parallel with two ends of lead arm switching tubes and lagging switching tubes. Capacitors C1,C3 are connected in parallel with the lead arm switching tubes S1,S3. A homonymous terminal at the primary side of a transformer TX1 is connected to a transmitting terminal of the lead arm switching tube S1. A synonymous terminal at the primary side of the transformer TX1 is connected to an inductor LIK. A homonymous terminal of the secondary side of the transformer is connected to the anode of a diode D6, while a synonymous terminal of the secondary side is connected to the anode of a diode D5. An output coupling inductive circuit is added to the cathodes of the diodes D5,D5 and two ends of the center of the secondary side of the transformer. The output coupling inductive circuit mainly consists of a clamp capacitor Ch, an output coupling inductor Lc, and diodes Df,Dd,Dc. The converter can realize zero voltage zero current soft switching at a wider load range. Auxiliary circuits have no dissipative elements. The inductor does not need to store energy in advance. The stress of the current at the primary side is not increased.

The invention provides a 3D integrated framework of an ultrahigh frequency power converter. The 3D integrated framework comprises a PCB circuit layer and a winding unit erected on the PCB circuit layer. The winding unit is connected with the PCB circuit layer through a wire. The winding unit comprises winding layers formed on a first insulating layer and a first soft magnetic thin film layer formed on a second insulating layer. The first soft magnetic thin film layer is arranged below the winding layers in a laminated mode to be used for achieving magnetic shielding between the winding layers and the PCB circuit layer. Compared with the prior art, by the adoption of 3D integration, the size of the converter is reduced, and the power density is increased; soft magnetic materials are adopted to form the magnetic shielding layer, magnetic field interference between windings and the PCB circuit layer and between the windings and external metal is solved, the Q value of the windings is increased, the alternating current resistance and high-frequency loss of an inductor and a transformer are reduced, and the working efficiency of the converter is improved; a plane magnetic element is further adopted, and the miniaturization and flattening of products are guaranteed; temperature rising of the magnetic element is reduced greatly, and the working environment of a semiconductor device is improved.

A phase shift full bridge converter with a reduced current stress includes: a switching unit that switches an input voltage; a transformer that includes a first capacitor serially connected to, and having a primary side and a secondary side; an auxiliary circuit unit that includes a first switch, a second switch, and a second capacitor, which are connected in parallel to the secondary side of the transformer; and a rectification unit that is connected to the auxiliary circuit unit, with an output inductor being removed.

The invention relates to a multiphase parallel resonant converter for an electrodeless lamp and a light adjusting control method. The multiphase parallel resonant converter is composed of a switching network, a resonant network and an electrodeless lamp load. The switching network is composed of n bridge arms which are connected in parallel, wherein one bridge arm is used as a phase-shift bridge arm and is used for light adjusting control, the rest (n-1) bridge arms which are connected in parallel are same-phase drive bridge arms, the power output of the resonant converter can be enlarged, and the current stress of a switching tube is reduced. The light adjusting control method in which phase shift and phase lock are combined is also provided. The parallel resonant converter can always work nearby the inherent resonance points of the resonant network in the same-phase driving and phase-shift light adjusting process, adverse effects of drifting of the inherent resonance points caused by the change of the resonant network and lamp load parameters on the work of the lamp are avoided, and it is guaranteed that the electrodeless lamp works stably and reliably.