CN104617777B - High-gain low-switching-voltage stress interleaved BOOST converter and working method - Google Patents

Abstract

The invention discloses a high-gain low-switching-voltage stress interleaved BOOST converter and a working method. One end of a first inductor is connected with a drain electrode of a first MOS tube, the other end of the first inductor is connected with one end of a second inductor, a source electrode of the first MOS tube is connected with a source electrode of a second first MOS tube, the source electrode of the second first MOS tube is connected with a third MOS tube, a drain electrode of the second first MOS tube is connected with the other end of the second inductor, one end of the second inductor is further connected with the leakage inductance end of a transformer, the other leakage inductance end of the transformer is connected with the input end of the primary side of the transformer, and a drain electrode of the third MOS tube is connected with the output end of the primary side of the transformer and the positive pole of a fourth diode. Therefore, the lower-voltage-level diode and the lower-breakover-resistance MOS tubes can be selected to further reduce switching loss and breakover loss.

Description

High-gain low switch voltage stress crisscross parallel BOOST converter and method of work

Technical field

The present invention relates to electronic circuit automation control area, more particularly, to a kind of high-gain low switch voltage stress interlocks BOOST converter in parallel and method of work.

Background technology

With the in short supply and serious environmental problem of global energy, new forms of energy resource such as photovoltaic, fuel cell, wind energy, underground heat Can wait and widely be paid close attention in the whole world.However, the output voltage of most of new forms of energy resources such as photovoltaic, fuel cell is relatively low, Need a kind of converter of high-gain in actual applications.In theory, boost, buck-boost and flyback converter is in pole Higher voltage gain can be provided during the dutycycle of end.It is true that the voltage gain of these converters is but limited to switching tube, two The equivalent series resistance of pole pipe, inductance and electric capacity, the impact of leakage inductance.And, not only can introduce very big in extreme dutycycle Current ripples and increase conduction loss, also can introduce very serious diode reverse recovery problem.

Therefore, for improving converter conversion efficiency and avoiding the extreme dutycycle situation of work, many quadratic transformation devices and The 2 stage converter of tandem structure is suggested.Then, because the converter topology of two-layer configuration is complicated, efficiency reduces.And, The stability of converter is a problem and the reverse-recovery problems than more serious output diode.As a result, final efficiency ratio Relatively low, corresponding electromagnetic interference (EMI) noise ratio is more serious.Isolated converter can be easy in the case of having transformer The higher voltage gain of acquisition.However, the leakage inductance of transformer not only results in voltage and current spike, introduce higher switch Tube voltage stress, but also loss and noise can be increased, result leads to less efficient.RCD clamp circuit and active clamping circuir Voltage stress and switching loss can be reduced, but be lost as cost with converter topology complex structure and related clamp circuit 's.

In order to obtain higher conversion efficiency, the substantial amounts of non-isolated converter based on coupling inductance is due to its circuit structure Simple and conduction loss is little and be widely studied.However, they but need buffer to be caused by the leakage inductance of coupling inductance to limit Switch tube voltage spike.Therefore, voltage clamping circuit, active clamping circuir, passive regeneration buffer circuit has been suggested solution Certainly this problem.However, all these methods are all by increasing switching tube and electric capacity, which results in transformer configuration and become multiple Miscellaneous.Based on the non-isolated high-gain converter of the integrated isolated converter of boost, such as integrated boost-flyback converter and collection Boost-SEPIC converter is become to be suggested in the literature.Coupling inductance, as transformer, is improved by adjusting winding turns ratio Voltage gain.Additionally, leakage inductance energy directly recycles in output end, so, the due to voltage spikes of switching tube can be limited.And And, the cut-off current of output diode can be coupled the leakage inductance restriction of inductance, and the reverse-recovery problems of diode alleviate, related Loss also reduce.However, the voltage stress of output diode but increased with the increase of the turn ratio of coupling inductance.Cause This, the reverse-recovery problems of diode yet suffer from.Although avoiding extreme dutycycle, input current ripple is due to the list of circuit Switch control rule but becomes very big, and this makes these converters all be unsuitable for high-power, high current application scenario.Traditional is staggered Boost converter in parallel due to the simple and less input and output ripple of its result, in high-power and PFC should With in be reasonable selection.However, voltage gain ratio is relatively low, the voltage stress of switching tube and diode is close to output voltage In order to solve these problems, switching capacity, transformer or coupling inductance are integrated in traditional crisscross parallel boost converter. Therefore, obtain the converter being applied to powerful high-gain, high efficiency, low voltage stress.

Interleaving and Transformer Paralleling boost converter becomes new forms of energy because of the feature that its structure is simple and input and output ripple is little The preferable selection of system.However, the voltage gain of traditional crisscross parallel boost converter is relatively low.Therefore, forward converter andCode converter is integrated in traditional crisscross parallel boost converter and is suggested.Higher voltage can not only be obtained increase Benefit and the voltage stress of switching tube and diode can also be reduced.However, integrated forward converter andCode converter circuit Considerably complicated and expensive.For universal, with normal shock type andCode converter is compared, and flyback converter is obtained in that higher Voltage gain, and circuit structure is simpler.Therefore, flyback converter is integrated in traditional interleaved parallel converter It is also that another one preferably selects.

Content of the invention

It is contemplated that at least solving technical problem present in prior art, especially innovatively propose a kind of high-gain Low switch voltage stress crisscross parallel BOOST converter and method of work.

In order to realize the above-mentioned purpose of the present invention, the invention provides a kind of high-gain low switch voltage stress crisscross parallel BOOST converter, it is it is critical that include：First metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor, the first inductance, the second inductance, Transformer leakage inductance, the first diode, the second diode, the 3rd diode, the 4th diode, load, output capacitance, the first electricity Appearance, the second electric capacity, transformer,

First inductance one end connects the first metal-oxide-semiconductor drain electrode, and the described first inductance other end connects second inductance one end, described First metal-oxide-semiconductor source electrode connects the second metal-oxide-semiconductor source electrode, and described second metal-oxide-semiconductor source electrode connects the 3rd metal-oxide-semiconductor source electrode, described 2nd MOS Pipe drain electrode connects the second inductance other end, and described second inductance one end is also connected with transformer leakage inductance one end, described transformer leakage inductance Other end connection transformer primary side input, described 3rd metal-oxide-semiconductor drain electrode connection transformer primary side output end and the four or two Pole pipe positive pole, described 4th diode cathode connects the second metal-oxide-semiconductor drain electrode and second electric capacity one end, the described first inductance other end Be also connected with Circuit Fault on Secondary Transformer input and first electric capacity one end, the described first electric capacity other end connect the first diode cathode and 3rd diode cathode, described 3rd diode cathode connection transformer secondary side output end, described first diode cathode is even Connect the second electric capacity other end and the second diode cathode, described second diode cathode connects output capacitance one end and load respectively One end, the described output capacitance other end connects the 3rd metal-oxide-semiconductor source electrode, and the described load other end connects the 3rd metal-oxide-semiconductor source electrode.

Invention additionally discloses a kind of method of work of high-gain low switch voltage stress crisscross parallel BOOST converter, its It is critical that arranging three metal-oxide-semiconductor work schedules, a time cycle of metal-oxide-semiconductor on, off is divided into t₀、t₁、t₂、t₃、t₄、 t₅Six time points, described method of work includes：

Step 1, in t₀To t₁Stage, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor conducting, the first diode, the two or two Pole pipe, the 3rd diode, the 4th diode is all off, the first inductance, the electric current i in the second inductance and transformer leakage inductance_L1, i_L2And i_LlkLinearly increasing, load energy is provided by output capacitance, and the voltage at the 4th diode two ends is close to zero；

Step 2, in t₁To t₂Stage, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor conducting, the first metal-oxide-semiconductor turns off, the second diode, the Three diodes, the 4th diode turn off, the first diode current flow, are stored in energy in the first inductance and the first electric capacity and pass through the One diode is delivered to the second electric capacity, and output capacitance provides energy to load；

Step 3, in t₂To t₃Stage, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor conducting, the first diode, the two or two Pole pipe, the 3rd diode, the 4th diode is all off, the first inductance, the electric current i in the second inductance and transformer leakage inductance_L1, i_L2And i_LlkLinearly increasing, load energy is provided by output capacitance, and the voltage at the 4th diode two ends is close to zero；

Step 4, in t₃To t₄Stage, the first metal-oxide-semiconductor conducting, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor turn off, and the first diode closes Disconnected, the second diode, the 3rd diode, the 4th diode current flow, the electric current in the first inductance is linearly increasing, is stored in the second electricity Energy in sense and the second electric capacity is discharged into output capacitance and load by the second diode, meanwhile, is stored in transformer leakage inductance In energy pass through the 4th diode, the second electric capacity, the second diode is discharged into output capacitance and load, in t₄Moment, the 4th The electric current of diode and transformer leakage inductance is reduced to zero, and the energy being stored in transformer passes through the 3rd diode to the first electric capacity Release is to make up the energy of previous stage first electric capacity release；

Step 5, in t₄To t₅Stage, the first metal-oxide-semiconductor conducting, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor turn off, the second diode, the Three diode current flows, the first diode, the 4th diode turn off, and the electric current in the first inductance is linearly increasing, is stored in transformer In energy be released to the first electric capacity, output energy is provided by the second inductance and the second electric capacity.

The method of work of described high-gain low switch voltage stress crisscross parallel BOOST converter is it is preferred that described step Rapid 4 include：

The magnetizing inductance L of setting transformer_m, and assume K=L_m/(L_m+L_lk), transformer leakage inductance L_lkIn energy pass through the Four diodes are discharged into output end, exergonic dutycycle D_D4For：

The method of work of described high-gain low switch voltage stress crisscross parallel BOOST converter is it is preferred that also include The step of setting voltage gain：

Output V_oTo input V_INVoltage gain M, by the voltage-second balance principle of the first inductance and the second inductance, obtain：

V_IN+V_C1(1-D)-V_C2(1-D)=0,

V_IN+V_C2(1-D)-V_O(1-D)=0,

First electric capacity is the output capacitance of flyback converter, therefore, the voltage V of the first electric capacity_C1For：

K is the ratio that transformer primary side magnetizing inductance and former limit magnetizing inductance add transformer leakage inductance, and N is Transformer secondary umber of turn and the ratio of the primary side winding number of turn, D is dutycycle；

WillSubstitute into V_IN+V_C1(1-D)-V_C2(1-D)=0 and V_IN+V_C2(1-D)-V_O(1-D)=0 obtains The voltage of two electric capacity and output capacitance is respectively：

Therefore voltage gain is：

Because magnetizing inductance L_mMuch larger than transformer leakage inductance L_lk, close to 1, as K=1, ideal voltage gain is therefore K：

The method of work of described high-gain low switch voltage stress crisscross parallel BOOST converter is it is preferred that also include The step of setting voltage stress：

According to Kirchhoff's second law, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the first diode, the two or two Pole pipe, the 3rd diode, the voltage stress of the 4th diode must be：

Make K=1, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the first diode, the second diode, the three or two pole Pipe, the voltage stress distribution of the 4th diode are：

V_D4,max=0.

In sum, due to employing technique scheme, the invention has the beneficial effects as follows：

Described converter to reduce input and output ripple using Interleaving and Transformer Paralleling.Flyback converter is integrated in biography The crisscross parallel Boost of system, and the transformer primary side winding of flyback converter is directly connected with output end.Cause This, the leakage inductance energy of transformer can recycle, thus improve transducer effciency.Additionally, increased switching capacity conduct Reducing the voltage stress of switching tube and diode, this makes the diode of more low-voltage-grade and has lower conducting divider The switching tube of resistance can be selected to reduce switching loss and conduction loss further.

The additional aspect of the present invention and advantage will be set forth in part in the description, and partly will become from the following description Obtain substantially, or recognized by the practice of the present invention.

Brief description

The above-mentioned and/or additional aspect of the present invention and advantage will become from reference to the description to embodiment for the accompanying drawings below Substantially and easy to understand, wherein：

Fig. 1 is high-gain switching voltage stress crisscross parallel BOOST variator circuit diagram of the present invention；

Fig. 2 is high-gain switching voltage stress crisscross parallel BOOST variator oscillogram of the present invention；

Fig. 3 is high-gain switching voltage stress crisscross parallel BOOST variator equivalent circuit diagram of the present invention；

Fig. 4 is high-gain switching voltage stress crisscross parallel BOOST variator equivalent circuit diagram of the present invention；

Fig. 5 is high-gain switching voltage stress crisscross parallel BOOST variator equivalent circuit diagram of the present invention；

Fig. 6 is high-gain switching voltage stress crisscross parallel BOOST variator equivalent circuit diagram of the present invention.

Specific embodiment

Embodiments of the invention are described below in detail, the example of described embodiment is shown in the drawings, wherein from start to finish The element that same or similar label represents same or similar element or has same or like function.Below with reference to attached The embodiment of figure description is exemplary, is only used for explaining the present invention, and is not considered as limiting the invention.

In describing the invention it is to be understood that term " longitudinal ", " horizontal ", " on ", D score, "front", "rear", The orientation of instruction such as "left", "right", " vertical ", " level ", " top ", " bottom " " interior ", " outward " or position relationship are based on accompanying drawing institute The orientation showing or position relationship, are for only for ease of the description present invention and simplify description, rather than the dress of instruction or hint indication Put or element must have specific orientation, with specific azimuth configuration and operation, therefore it is not intended that limit to the present invention System.

In describing the invention, unless otherwise prescribed and limit, it should be noted that term " installation ", " being connected ", " connection " should be interpreted broadly, for example, it may be the connection of mechanical connection or electrical connection or two element internals, can To be to be joined directly together it is also possible to be indirectly connected to by intermediary, for the ordinary skill in the art, can basis Concrete condition understands the concrete meaning of above-mentioned term.

As shown in figure 1, the invention provides a kind of high-gain low switch voltage stress crisscross parallel BOOST converter, its It is critical that including：First metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor, the first inductance, the second inductance, transformer leakage inductance, first Diode, the second diode, the 3rd diode, the 4th diode, load, output capacitance, the first electric capacity, the second electric capacity, transformation Device,

First inductance one end connects the first metal-oxide-semiconductor drain electrode, and the described first inductance other end connects second inductance one end, described First metal-oxide-semiconductor source electrode connects the second metal-oxide-semiconductor source electrode, and described second metal-oxide-semiconductor source electrode connects the 3rd metal-oxide-semiconductor source electrode, described 2nd MOS Pipe drain electrode connects the second inductance other end, and described second inductance one end is also connected with transformer leakage inductance one end, described transformer leakage inductance Other end connection transformer primary side input, described 3rd metal-oxide-semiconductor drain electrode connection transformer primary side output end and the four or two Pole pipe positive pole, described 4th diode cathode connects the second metal-oxide-semiconductor drain electrode and second electric capacity one end, the described first inductance other end Be also connected with Circuit Fault on Secondary Transformer input and first electric capacity one end, the described first electric capacity other end connect the first diode cathode and 3rd diode cathode, described 3rd diode cathode connection transformer secondary side output end, described first diode cathode is even Connect the second electric capacity other end and the second diode cathode, described second diode cathode connects output capacitance one end and load respectively One end, the described output capacitance other end connects the 3rd metal-oxide-semiconductor source electrode, and the described load other end connects the 3rd metal-oxide-semiconductor source electrode.

In the circuit proposing in Fig. 1.Switching tube S₃There is provided an inflow output end for the electric current in static exciter inductance Path, therefore reduce switching tube S₂Current stress and conduction loss, reduce input current ripple.Work as S₂During shutoff, two Pole pipe D₄Stop and be stored in inductance L₂In energy transmission in transformer primary side winding, but allow it be delivered to output end.With When, by D₄The leakage inductance energy of converter can be used in output end.Diode D₄Voltage stress close to zero, this is great Reduce D₄Reverse-recovery problems, thus improve efficiency.Switching tube S₃Use reduce S₂Current stress, thus can Think that this two switching tubes select the MOSFET of more low current level.Although increased a switching tube in circuit, loss But do not accordingly increase.Described S₁、S₂、S₃Grid connects controller respectively.

The operation principle of the converter proposing can the key job waveform from Fig. 2 can illustrate.To put it more simply, assuming In Fig. 2, all of element is all preferable except transformer, and all works in the steady state.In order to describe S₃And D₄Effect it is considered to Leakage inductance L of transformer_lk.In circuit analysis, the converter of proposition is operated in continuous mode (CCM), and under stable state, dutycycle is big In 0.5, switching tube S₁And S₂There is during work 180 ° of phase places, S₂And S₃There is during work 0 ° of phase place.The converter proposing is at one Stable state waveform in switch periods corresponds to 5 kinds of circuit operation modes.Operation mode is described as follows.

(1) mode 1 [t0<t≤t1]：Switching tube S₁, S₂, S₃Conducting, diode D₁, D₂, D₃, D₄All off, corresponding Current path such as Fig. 3.It can be seen that inductance L₁, L₂With transformer leakage inductance L_lkIn electric current i_L1, i_L2And i_LlkLinear increasing Plus, load energy is provided by output capacitance.Further, since S₂, S₃Conducting, diode D₄The voltage at two ends close to zero, therefore, D₄Reverse-recovery problems be greatly reduced, corresponding efficiency improves.

(2) mode 2 [t1<t≤t2]：Switching tube S₂, S₃Still turn on, S₁Turn off, diode D₂, D₃, D₄Turn off, D₁Lead Logical, corresponding current path such as Fig. 4.It is stored in inductance L₁With electric capacity C₁In energy pass through D₁It is delivered to C₂, output capacitance C_oStill There is provided energy so to load R.

(3) mode 3 [t2<t≤t3]：From figure 3, it can be seen that S₁, S₂, S₃Conducting, corresponding current path and Fig. 3 phase With.

(4) mode 4 [t3<t≤t4]：S₁Conducting, S₂, S₃Turn off, D₁Turn off, D₂, D₃, D₄Conducting, corresponding current path As Fig. 5.Inductance L₁In electric current linearly increasing, be stored in inductance L₂With electric capacity C₂In energy pass through D₂It is discharged into output capacitance C_o With load R.Meanwhile, it is stored in leakage inductance L_lkIn energy pass through D₄, C₂, D₂It is discharged into C_oWith load R.In t₄Moment, D₄And L_lk's Electric current is reduced to zero.Additionally, the energy being stored in transformer passes through D₃To electric capacity C₁Release is to make up previous stage C₁Release Energy.

(5) mode 4 [t4<t≤t5]：Switching tube S₁Still turn on, S₂, S₃Turn off, diode D₂, D₃Conducting, D₁, D₄Close Disconnected, corresponding current path such as Fig. 6.Inductance L₁In electric current still linearly increasing, the energy being stored in transformer is still released Put to C₁, output energy is by inductance L₂With electric capacity C₂There is provided.So far, complete the working condition of switch periods.

The magnetizing inductance L of transformer will be considered_m, and assume K=L_m/(L_m+L_lk).In mode 4, leakage inductance L_lkIn energy By D₄It is discharged into output end, exergonic dutycycle D_D4For：

Additionally, can easily find out from Fig. 3-6, the dutycycle under other mode (1,2,3,5) is respectively (D- 0.5), (1-D), (D-0.5), (1-D) (N-1)/(1+N).

Voltage gain

Export V first_oTo input V_INVoltage gain M (or voltage conversion rate).By inductance L₁And L₂Voltage-second balance former Reason, can obtain：

V_IN+V_C1(1-D)-V_C2(1-D)=0 (2)

V_IN+V_C2(1-D)-V_O(1-D)=0 (3)

Switching capacity C₁It is considered as the output capacitance of flyback converter, therefore, C₁Voltage V_C1For：

K is the ratio that transformer primary side magnetizing inductance and former limit magnetizing inductance add transformer leakage inductance, i.e. transformer primary side inductance The coefficient of coup, N is the ratio of transformer secondary umber of turn and the primary side winding number of turn.D is dutycycle.

(4) substitution (2) and (3) can be obtained electric capacity C₂And C_oVoltage be respectively：

Therefore voltage gain is：

Because magnetizing inductance L_mMuch larger than leakage inductance L_lk, therefore K is close to 1.As K=1, ideal voltage gain is：

The converter proposing and ideal voltage gain in K=1, the function relation curve with dutycycle during N=3.Propose Converter can easily obtain high voltage gain than other two converters.In identical voltage gain, the conversion of proposition Utensil has less dutycycle, and therefore, extreme dutycycle is avoided that, conduction loss also can reduce.

Each element voltage stress

Voltage stress for ease of each element of the converter proposing is analyzed, and ignores the ripple voltage of electric capacity, according to Kiel Hough voltage law, each switching tube S₁-S₃With diode D₁-D₄Voltage stress can be：

Compare for convenience, ignore transformer leakage inductance L_lk, that is, making K=1, the voltage stress of each switching tube and diode divides Cloth is：

V_D4,max=0 (18)

It can be seen that the voltage stress of each switching tube is much smaller than V from (15) formula_O/ 2, therefore, switching loss and conducting are damaged Power consumption is enough to be reduced.From (18), formula can be seen that diode D₄Voltage stress close to zero, its reverse-recovery problems greatly subtracts Little, thus the diode of more low-voltage-grade can be selected to reduce switch and conduction loss further.

The consideration of the mode of operation of converter proposing

For the application of new forms of energy resource such as photovoltaic, fuel cell, need a kind of voltage gain height, input current ripple little DC converter.It is therefore proposed converter be one and preferably select.Due to cross structure, the converter of proposition is not only Higher voltage gain is provided, and extends the service life of fuel cell and battery block by suppressing input current ripple. The converter proposing is operated in continuous mode (CCM) and is more suitable for than being operated in discrete mode (DCM).In DCM pattern, although energy Produce big output voltage and there is little dutycycle, but output voltage is more sensitive to dutycycle.Therefore, closed-loop feedback circuit Design more complicated.And, during DCM pattern, input current ripple is larger, so that the service life of fuel cell can be shortened, Corresponding system effectiveness also can reduce.It is therefore proposed that converter be unsuitable for the application of new energy resources system in DCM pattern, this Invention only considers the situation of CCM pattern.When dutycycle is less than 0.5, the converter of proposition still can work, but now transformer The voltage on secondary side is relatively low, and result makes output voltage relatively low.Therefore, the present invention only considers the situation that dutycycle is more than 0.5.

The practicality of the converter proposing for checking, has built an input 24V, has exported 200V, 200W, switching frequency The experimental prototype of 50KHZ.

In the design of this paper experimental prototype parameter, crucial design procedure is to can guarantee that area of safety operaton and select lower The design of the transformer turns ratio of electric pressure element.After transformer turns ratio determines, dutycycle can rationally determine.Then, switch Pipe, diode, the electric pressure of electric capacity can easily select.It is true that switching tube, diode, dutycycle, the choosing of the turn ratio Select and need compromise to process.

The staggered pulsewidth modulation MOSFET gate signal voltage V of measurement_GS1,V_GS2And V_GS3.As can be seen that dutycycle D is more than 0.5, and be 0.56, switching tube S₁, S₂Driving gate signal phase be 180 °, S₂, S₃Driving gate signal phase be 0 °.

Model machine component parameter

Just can easily obtain the output voltage of 200V in low-down dutycycle 0.56, each switching capacity is to reduce The voltage stress of each switching tube and diode assume responsibility for most of voltage.It is demonstrated experimentally that its voltage is about 54V, much smaller than defeated Go out voltage, and 1/4 close to output voltage.It is thereby possible to select the switching tube of more low-voltage-grade reduces conducting further damaging Consumption and switching loss.It is demonstrated experimentally that D₂Voltage be about 54V, equal to the voltage of switching tube, (15) the formula phase with steady-state analysis Symbol, D₁Voltage be much smaller than output voltage.As (18) formula, the voltage of the D4 recording is close to zero.It is thereby possible to select more The diode of low-voltage-grade, and the reverse-recovery problems of diode can be reduced accordingly.By measuring i_D2,i_C2,i_Llk Current waveform.By measuring input current i_IN, inductive current i_L1And i_L2Waveform it can be seen that due to cross structure, defeated Enter electric current and there is less ripple.

Finally, as input voltage VIN=27V, peak efficiency is about 97.1%, and full load is about 91.8%.Work as input When voltage is reduced to 20V, peak efficiency is 96%.The efficiency of converter improves with the increase of input voltage.When input electricity When pressure increases, input current and dutycycle reduce, and therefore, related loss reduces.Converter in the same terms VIN=24V, VO=200V, efficiency curve during load change.

Converter of the present invention is flyback and switching capacity is integrated in a traditional crisscross parallel boost converter, this Plant transformer configuration to be used for reducing input and output ripple.Flyback converter is designed to improve voltage gain, it is to avoid be operated in Extreme dutycycle situation.Additionally, switching capacity to reduce the voltage stress of switching tube and diode as divider.So, relatively The switching tube of the diode of low-voltage-grade and less conducting resistance can be selected to reduce switch and conduction loss further. The primary side winding being additionally, since transformer is directly connected with output point, and leakage inductance energy can be recycled, by main switch Due to voltage spikes also can be reduced.Thus, corresponding efficiency is enhanced.

In the description of this specification, reference term " embodiment ", " some embodiments ", " example ", " specifically show The description of example " or " some examples " etc. means specific features, structure, material or the spy describing with reference to this embodiment or example Point is contained at least one embodiment or the example of the present invention.In this manual, to the schematic representation of above-mentioned term not Necessarily refer to identical embodiment or example.And, the specific features of description, structure, material or feature can be any One or more embodiments or example in combine in an appropriate manner.

Although an embodiment of the present invention has been shown and described, it will be understood by those skilled in the art that：Not Multiple changes, modification, replacement and modification can be carried out to these embodiments in the case of the principle of the disengaging present invention and objective, this The scope of invention is limited by claim and its equivalent.

Claims (4)

1. a kind of high-gain low switch voltage stress crisscross parallel BOOST converter is it is characterised in that include：First metal-oxide-semiconductor, Second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor, the first inductance, the second inductance, transformer leakage inductance, the first diode, the second diode, the three or two Pole pipe, the 4th diode, load, output capacitance, the first electric capacity, the second electric capacity, transformer,

First inductance one end connects the first metal-oxide-semiconductor and drains, described first inductance other end connection second inductance one end, and described first Metal-oxide-semiconductor source electrode connects the second metal-oxide-semiconductor source electrode, and described second metal-oxide-semiconductor source electrode connects the 3rd metal-oxide-semiconductor source electrode, described second metal-oxide-semiconductor leakage Pole connects the second inductance other end, and described second inductance one end is also connected with transformer leakage inductance one end, and described transformer leakage inductance is another End connection transformer primary side input, described 3rd metal-oxide-semiconductor drain electrode connection transformer primary side output end and the 4th diode Positive pole, described 4th diode cathode connects the second metal-oxide-semiconductor drain electrode and second electric capacity one end, and described first inductance one end is also connected with Circuit Fault on Secondary Transformer input and first electric capacity one end, the described first electric capacity other end connects the first diode cathode and the three or two Pole pipe negative pole, described 3rd diode cathode connection transformer secondary side output end, described first diode cathode connects second The electric capacity other end and the second diode cathode, described second diode cathode connects output capacitance one end and load one end respectively, The described output capacitance other end connects the 3rd metal-oxide-semiconductor source electrode, and the described load other end connects the 3rd metal-oxide-semiconductor source electrode；

The method of work of described high-gain low switch voltage stress crisscross parallel BOOST converter is that three metal-oxide-semiconductors of setting work Sequential, a time cycle of metal-oxide-semiconductor on, off is divided into t₀、t₁、t₂、t₃、t₄、t₅Six time points, step is as follows：

Step 1, in t₀To t₁Stage, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor conducting, the first diode, the two or two pole Pipe, the 3rd diode, the 4th diode is all off, the first inductance, the electric current i in the second inductance and transformer leakage inductance_L1, i_L2 And i_LlkLinearly increasing, load energy is provided by output capacitance, and the voltage at the 4th diode two ends is close to zero；

Step 2, in t₁To t₂Stage, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor conducting, the first metal-oxide-semiconductor turns off, the second diode, the three or two Pole pipe, the 4th diode turn off, the first diode current flow, and the energy being stored in the first inductance and the first electric capacity passes through the one or two Pole pipe is delivered to the second electric capacity, and output capacitance provides energy to load；

Step 3, in t₂To t₃Stage, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor conducting, the first diode, the two or two pole Pipe, the 3rd diode, the 4th diode is all off, the first inductance, the electric current i in the second inductance and transformer leakage inductance_L1, i_L2 And i_LlkLinearly increasing, load energy is provided by output capacitance, and the voltage at the 4th diode two ends is close to zero；

Step 4, in t₃To t₄Stage, the first metal-oxide-semiconductor conducting, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor turn off, and the first diode turns off, the Two diodes, the 3rd diode, the 4th diode current flow, the electric current in the first inductance is linearly increasing, be stored in the second inductance and Energy in second electric capacity is discharged into output capacitance and load by the second diode, is stored in transformer leakage inductance meanwhile Energy passes through the 4th diode, the second electric capacity, and the second diode is discharged into output capacitance and load, in t₄Moment, the four or two pole The electric current of pipe and transformer leakage inductance is reduced to zero, and the energy being stored in transformer is discharged to the first electric capacity by the 3rd diode To make up the energy of previous stage first electric capacity release；

Step 5, in t₄To t₅Stage, the first metal-oxide-semiconductor conducting, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor turn off, the second diode, the three or two Pole pipe turns on, and the first diode, the 4th diode turn off, and the electric current in the first inductance is linearly increasing, is stored in transformer Energy is released to the first electric capacity, and output energy is provided by the second inductance and the second electric capacity.

2. high-gain low switch voltage stress crisscross parallel BOOST converter according to claim 1 it is characterised in that Described step 4 includes：

The magnetizing inductance L of setting transformer_m, and assume K=L_m/(L_m+L_lk), transformer leakage inductance L_lkIn energy pass through the four or two Pole pipe is discharged into output end, exergonic dutycycle D_D4For：

$D_{D4}=\frac{2(1-D)}{1+N}.$

3. high-gain low switch voltage stress crisscross parallel BOOST converter according to claim 1 it is characterised in that Also include the step that voltage gain is set：

Output V_oTo input V_INVoltage gain M, by the voltage-second balance principle of the first inductance and the second inductance, obtain：

V_IN+V_C1(1-D)-V_C2(1-D)=0,

V_IN+V_C2(1-D)-V_O(1-D)=0,

First electric capacity is the output capacitance of flyback converter, therefore, the voltage V of the first electric capacity_C1For：

K is the ratio that transformer primary side magnetizing inductance and former limit magnetizing inductance add transformer leakage inductance, and N is transformation The device vice-side winding number of turn and the ratio of the primary side winding number of turn, D is dutycycle；

WillSubstitute into V_IN+V_C1(1-D)-V_C2(1-D)=0 and V_IN+V_C2(1-D)-V_O(1-D)=0 obtains the second electric capacity It is respectively with the voltage of output capacitance：

$V_{C2}=\frac{1+KND}{1-D}{V}_{IN},$

$V_O=\frac{2+KND}{1-D}{V}_{IN},$

Therefore voltage gain is：

$M=\frac{V_O}{V_{IN}}=\frac{2+KND}{1-D},$

Because magnetizing inductance L_mMuch larger than transformer leakage inductance L_lk, close to 1, as K=1, ideal voltage gain is therefore K：

$M=\frac{2+ND}{1-D}.$

4. high-gain low switch voltage stress crisscross parallel BOOST converter according to claim 1 it is characterised in that Also include the step that voltage stress is set：

According to Kirchhoff's second law, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the first diode, the two or two pole Pipe, the 3rd diode, the voltage stress of the 4th diode must be：

$V_{S1,\max }=V_{S2,\max }=\frac{V_{IN}}{1-D}=\frac{V_O}{2+KND},$

$V_{S3,\max }=\frac{V_O}{2(2+KND)}(2+KD-D+ND-KND),$

$V_{D1,\max }=\frac{2V_{IN}}{1-D}=\frac{2V_O}{2+KND},$

$V_{D2,\max }=\frac{V_{IN}}{1-D}=\frac{V_O}{2+KND},$

$V_{D3,\max }=\frac{{\mathrm{NV}}_{IN}}{1-D}=\frac{{\mathrm{NV}}_O}{2+KND},$

$V_{D4,\max }=\frac{V_O}{2(2+KND)}(D-KD+KND-ND),$

Make K=1, the first metal-oxide-semiconductor, the second metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the first diode, the second diode, the 3rd diode, The voltage stress distribution of four diodes is：

$V_{S1,\max }=V_{S2,\max }=V_{S3,\max }=V_{D2,\max }=\frac{V_{IN}}{1-D}=\frac{V_O}{2+ND},$

$V_{D1,\max }=\frac{2V_{IN}}{1-D}=\frac{2V_O}{2+ND},$

$V_{D3,max}=\frac{{\mathrm{NV}}_{IN}}{1-D}=\frac{{\mathrm{NV}}_O}{2+ND},$

V_D4,max=0.