399results about How to "Reduce current stress" patented technology

The invention discloses a multi-port isolating bidirectional DC-DC (direct current to direct current) converter which is used for a mixed energy storing system. The converter comprises a phase-shifting transformer and a primary side circuit and a secondary side circuit which are respectively connected with a primary side and a secondary side of the phase-shifting transformer; the secondary side circuit comprises a two-path Buck / Boost converting circuit, wherein the two-path Buck / Boost converting circuit comprises two input / output ends and two bridge arm midpoints and the two bridge arm midpoints are respectively connected with two ends of the secondary side of the phase-shifting transformer; and the primary side circuit comprises at least one two-path Buck / Boost converting circuit, wherein the two-path Buck / Boost converting circuit comprises two input / output ends and two bridge arm midpoints and the two bridge arm midpoints are respectively connected with two ends of the primary side of the phase-shifting transformer. The invention further discloses a voltage matching and controlling method of the multi-port isolating bidirectional DC-DC converter and the mixed energy storing system comprising the converter. Compared with the prior art, the multi-port isolating both-way DC-DC converter can realize complete matching of voltage at two ends of a transformer and can prolong the service lives of a storage battery and a super capacitor.

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 discloses an electric car modularization power system based on parallel connection of batteries and a control method. The electric car modularization power system comprises a battery system and a motor control system, wherein the battery system comprises a power supply battery pack and a battery management system, the motor control system comprises an inverter and an inverting control module, the battery management system is used for managing, sampling and controlling the power supply battery pack, the power supply battery pack is connected to the inverter through a conducting wire, the inverter is used for inverting direct currents into three-phase electric power with adjustable voltage and frequency, which is supplied to a traction motor, and the inverting control module is used for controlling the inverter and is in communication with the battery management system through a bus; power supply batteries are connected in parallel, the power supply battery pack is divided into n groups, the n groups of batteries are respectively used for supplying power to the traction motor by adopting inverter circuits, and the motor control system is combined with the battery management system, and thus the standardization and the modularization of the power system are facilitated, and the management and the replacement of the batteries are convenient.

The invention discloses a bidirectional direct current converter based on an immittance network, and a digital control system and a digital control method of the bidirectional direct current converter. The bidirectional direct current converter based on the immittance network comprises a storage battery, a low-voltage-side filter capacitor, a first active full-bridge circuit, the immittance network, a high-frequency transformer, a second active full-bridge circuit and a high-voltage-bus-side filter capacitor. The digital control system comprises a first voltage sensor, a second voltage sensor, a current sensor and a digital signal processing (DSP) digital controller, wherein the DSP digital controller comprises a BUCK controller, a BOOST controller, a signal conditioner, a first selective switch and a second selective switch. According to the basic characteristics of the immittance network, the two active full-bridge circuits in the bidirectional direct current converter can operate with high power factor, and the current stress of a switching tube can be greatly reduced. By the adoption of the system and the method, according to the characteristics of the immittance network, the zero-current turn on and zero-current turn off of all switching devices of a high-voltage-side active full-bridge circuit are realized, and the efficiency of the converter is 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.

The invention discloses a PWM plus dual phase-shifting control method for a bidirectional DC / DC convertor. The method includes the steps of collecting the port voltage of the bidirectional DC / DC convertor in real time, and computing the duty ratio of a control signal when rematch of the leakage inductance voltage is conducted; acquiring the outward phase-shift angle j output by a circuit closed-loop controller; computing the inward phase-shift angle j0 acted on a second bridge arm of a modified H bridge when circuit power circulation is eliminated totally according to the obtained duty ratio and the outward phase-shift angle; generating the parameters of the outward phase-shift angle, the duty ratio and the inward phase-shift angle into a control signal of the circuit. The PWM plus dual phase-shifting control method for the bidirectional DC / DC convertor has the advantages of being suitable for the convertor with the bi-directional DC / DC topological structure, wherein one side of the convertor is the modified H bridge, the other side of the convertor is buck, boost or other derived circuits, reducing the current stress of a circuit switch device, expanding the soft switching range of the circuit, completely eliminating the circulation power in the circuit when the circuit works under different working conditions of light or heavy load, and improving work efficiency of the circuit.

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 invention discloses a minimum backflow power phase shift control method for an isolated-type bidirectional DC converter, and relates to the technical field of power and electronic transformer control methods. The method comprises the following steps: enabling a control system to control a sampling chip to collect an output voltage V2 and an output current i2, and determining the output power of the converter through the output voltage V2 and the output current i2; obtaining a standard transmission power p through dividing the transmission power by the maximum transmission power PN of the isolated-type bidirectional DC converter; calculating an internal phase shift angle d1 according to different ranges of the standard transmission power p and a minimum backflow power; solving the difference between the output voltage V2 and a given output voltage V2ref, and obtaining an external phase shift angle d2 through a PI controller; carrying out the pulse generation according to the internal phase shift angle d1 and the external phase shift angle d2, and enabling the output voltage V2 to be constant through the closed-loop adjustment of the value of the external phase shift angle d2 The method is simple in control, and is easy to implement.

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 high-power bidirectional multi-way direct-current simulation power supply. The high-power bidirectional multi-way direct-current simulation power supply is characterized by consisting of at least two mutually insulated simulation direct-current power supply units, wherein each simulation direct-current power supply unit comprises an AC / DC converter and a DC / DC converter which are connected in series; an input end of each AC / DC converter is connected with a secondary side winding of an input transformer; an input end of each DC / DC converter is connected with a capacitor in parallel, and a positive electrode of an output end of each DC / DC converter is connected with a diode in series; two ends of each diode are respectively connected with a switch in parallel. The high-power bidirectional multi-way direct-current simulation power supply is universal in function, only needs to adopt different control strategies, can widen the functions without replacing hardware, and solves the problems of high testing cost of existing DC equipment, small capacity, difficulty in expansion, single voltage level and functions and the like.

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 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 provides a GOA circuit. According to the GOA circuit, a second thin film transistor is arranged in an output module, the drain electrode of the second thin film transistor is electrically connected with the source electrode of a first thin film transistor, a first control signal is accessed to the grid electrode of the second thin film transistor, an Mth clock signal is accessed to the source electrode of the second thin film transistor, and opening and closure of the second thin film transistor are controlled through the first control signal; or the drain electrode of the secondthin film transistor is electrically connected with the source electrode of the first thin film transistor, the Mth clock signal is accessed to the grid electrode of the second thin film transistor,the source electrode of the second thin film transistor is electrically connected with a first node, and then the second thin film transistor is communicated when the Mth clock signal is at a high level and the first node is at a high level, and is cut off at other moments. Therefore, a voltage difference between the source electrode and the drain electrode of the first thin film transistor is avoided, the current stress to the first thin film transistor is reduced, and the product quality is effectively improved.

A flyback power converter and electronic apparatus suitable for synchronous rectification are disclosed. The flyback power converter includes a voltage transformer, a main switch, a synchronous rectification switch, a synchronous rectification control circuit, a sampling circuit and an operation circuit. A control end of the main switch receives a main switch signal so as to control the main switch. The synchronous rectification control circuit transmits control signal to control end of the synchronous rectification switch according to sensing signal received. The sampling circuit samples the state of the synchronous rectification switch so as to generate first logic signal and second logic signal. The operation circuit executes timing for charging / discharging according to the first and the second logic-signal, so as to output switch cut-off pulse signal to a voltage-dividing circuit. If voltage of the sensing signal is lower than predetermined threshold voltage, the synchronous rectification switch enters into cut-off state according to the control signal.

A multi-transformer push-pull type photovoltaic inverter comprises a DSP, a DC / DC convertor, a DC / AC convertor and a filter, wherein the DC / DC convertor, the DC / AC convertor and the filter are sequentially connected, and a composite controller which is composed of a PI controller of the DC / AC convertor, an artificial neural network model and a feed-forward arithmetic unit is arranged in the DSP. The input end of the artificial neural network model is connected with the state variable of the DC / AC convertor in the kappath sampling period, a predicted value of the output voltage which is outputted by the artificial neural network model in the (kappa+1)th sampling period is connected with the negative input end of the feed-forward arithmetic unit, the positive input end of the feed-forward arithmetic unit is connected with a set value of voltage at the kappa moment, and an output signal of the feed-forward arithmetic unit is connected with an output signal of he PI controller and then controls the duty ratio of the DC / AC convertor. According to the multi-transformer push-pull type photovoltaic inverter, the output voltage of the inverter at the next moment is predicted through the neural network model, compensation for the duty ratio at the present moment is timely conducted through the feed-forward arithmetic unit, and therefore the hysteresis quality of the PI controller is overcome, and the robustness of the inverter system is improved.

The invention discloses a resonant converter and a method for controlling the same, and belongs to the technical field of power electronics converters. The resonant converter comprises two high-frequency square-wave voltage sources (u<P1> and u<P2>), two resonant inductors (L<r1> and L<r2>), two resonant capacitors (C<r1> and C<r2>), two main inductors (L<m1> and L<m2>), two transformers (T<1> and T<2>), six diodes (D<1>, D<2>, D<3>, D<4>, D<5> and D<6>), an output filter capacitor (C<o>) and a load (R<o>). The frequencies and the pulse widths of the two high-frequency square-wave voltage sources are identical to one another, the frequencies of the two high-frequency square-wave voltage sources are fixed, and output voltages can be adjusted under phase-shift control between the two high-frequency square-wave voltage sources. The resonant converter and the method have the advantages that two resonant networks which are formed by the resonant inductors, the resonant capacitors and the main inductors constantly work at the fixed frequencies, and accordingly the resonant converter is simple in control and easy to implement; soft switching on all switch tubes and the diodes of the converter can be implemented in full-voltage and load ranges, high-frequency and efficient power conversion can be implemented, the sizes of the inductors and the sizes of the transformers can be effectively reduced, and high-power density effects can be realized.

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 provides a light emitting element driving circuit, wherein a plurality of LEDs (11a-11e) are connected in series, and an FET (13) which functions as a constant current source is arranged on one end. Switches (12a-12e) are connected in parallel to the LEDs (11a-11e). A switch control circuit (15) separately controls to turn on / off the switches (12a-12e) by using switch control signals (Xa-Xe), and changes the states of all the switches (12a-12e) in the same timing from the off-sate to the on state. The drive control circuit (14) may control the gate voltage of the FET (13) to a low level in timing when the switches (12a-12e) change to the on-state. Thus, luminances of the light emitting elements (LEDs) are separately adjusted and an overcurrent is prevented from flowing to the light emitting elements.

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.

The invention discloses an active current limiting method applicable to a direct current fault of an MMC direct current transformer. Additional bias <delta>u of a direct current component and gain Kuof an alternating current component of a bridge arm voltage are generated based on induction voltage drop <delta>U<dc2> output by a virtual impedance module; when the system is in steady state operation, the output current is constant, wherein <delta>U<dc2> is equal to 0, <delta>u is equal to 0, and Ku is equal to 1; when direct current fault occurs, the output current is increased suddenly, and <delta>U<dc2> is greater than 0; when <delta>U<dc2> exceeds the upper bond of a dead region, <delta>u is increased suddenly from 0 and then is limited to be kept stable until the <delta>u<max> is equalto U<dc2> / 2, so that the direct current bias in the bridge arm voltage is eliminated; meanwhile, by virtue of change of <delta>u, Ku is changed from 1 to 2 / n, so that the alternating current component amplitude value is in the bridge arm voltage is lowered, and the reference value of the bridge arm voltage is adjusted; and by virtue of the effect of a modulation module, the number of sub modulesinput in each phase of MMC in the fault side is reduced from n<sum>=n to n'<sum> belonging to {0, 1}, so that the number of sub modules participated in discharge at the same moment is reduced, the capacitor discharging speed is lowered, and current limiting is achieved.

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.

The invention discloses a vehicle charging converter with high efficiency. The vehicle charging converter with high efficiency includes successively connected EMI circuit, a PFC circuit, an inversioncircuit, a rectification circuit, an output circuit and a control circuit, wherein the EMI circuit is used for reducing the influence of high frequency noise of the converter on the power grid; on thepremise of guaranteeing the quality of the input current, the PFC circuit can convert the single phase alternating current into the high voltage direct current; the inversion circuit converts the high voltage direct current into high frequency square wave which is adjustable in frequency; the rectification circuit performs rectification after performing transformer isolation of the rectificationcircuit to obtain stable direct current voltage; and finally the high frequency current ripple is filtered and then is output by the output circuit, and the control circuit completes acquisition, calculation and output of the controlled quantity of the converter, and then operating and protection of the vehicle charging converter can be realized. In the vehicle charging converter with high efficiency, the PFC circuit and the inversion circuit respectively use GaN HEMT and Si MOSFET as the main switch devices; by means of combination with the advantages of a wide-gap semiconductor device and atotem PFC topology, the vehicle charging converter with high efficiency has the advantages of being good in the grid side harmonic wave characteristic, being small in volume, being flexible in control, and greatly improving the conversion efficiency of vehicle charging.