Summary of the invention
The application is by providing a kind of induction electric energy based on auxiliary induction transmission circulation control circuit system, it is achieved approximation
Zero current turning-on, zero voltage turn-off, reduce circulation peak value, reduces the switching loss of switching tube, it is suppressed that resonant network with
Bigger circulation between inversion network.
The application is achieved by the following technical solutions:
A kind of induction electric energy based on auxiliary induction transmission circulation control circuit system, including by the DC source E connected_{in}
With filter inductance L_{dc}The quasi-current source of composition, pulse generating circuit, high-frequency inversion network, former limit resonant network, secondary Resonance Neural Network
Network, rectifying and wave-filtering network and load, wherein, described quasi-current source is connected with described high-frequency inversion network, for described high-frequency inversion
Network provides unidirectional current, and described pulse generating circuit is connected with described high-frequency inversion network, and output control pulse controls described
The output waveform of high-frequency inversion network, described high-frequency inversion network is connected with described former limit resonant network, and output square wave current is given
Described former limit resonant network, described secondary resonant network receives the sinusoidal current of described former limit resonant network output, described secondary
Resonant network is connected with load by described rectifying and wave-filtering network, is exported by sinusoidal current to load, institute after rectifying and wave-filtering
State high-frequency inversion network and include the first switch S1, second switch S2, the 3rd switch S3 and the 4th switch S4, at described high-frequency inversion
It is provided with an auxiliary induction L between outfan and the described former limit resonant network of network_{1}, for damping the rate of climb of circulation
And peak value, and in each PWM cycle of pulse generating circuit, all there is described first switch S1, second switch S2, the 3rd open
Close the time T that S3 and the 4th switch S4 simultaneously turns on_{OV}, i.e. the overlapping conducting time, on the one hand give filter inductance L_{dc}Offer electric current returns
Road, on the other hand so that auxiliary induction L_{1}On electric current steadily commutate.
Further, described first switch S1 includes MOSFET pipe Q1 and antiparallel diode D1, described second switch
S2 includes that MOSFET pipe Q2 and antiparallel diode D2, described 3rd switch S3 include MOSFET pipe Q3 and antiparallel two poles
Pipe D3, described 4th switch S4 include MOSFET pipe Q4 and antiparallel diode D4, wherein, the source electrode of described MOSFET pipe Q1
Drain electrode with described MOSFET pipe Q2 is connected, and the source electrode of described MOSFET pipe Q3 is connected with the drain electrode of described MOSFET pipe Q4, institute
The drain electrode stating MOSFET pipe Q1 is connected with the drain electrode of described MOSFET pipe Q3, the source electrode of described MOSFET pipe Q1 and described MOSFET
The drain electrode of pipe Q4 connects, and the positive pole of all diodes all connects with the source electrode of corresponding MOSFET pipe, and the negative pole of all diodes is equal
Drain electrode with corresponding MOSFET pipe connects, and the grid of described MOSFET pipe is all connected with described pulse generating circuit, described
The source electrode of MOSFET pipe Q1 is as the first outfan of described high-frequency inversion network, and the source electrode of described MOSFET pipe Q3 is as described
Second outfan of high-frequency inversion network, described former limit resonant network includes the resonant capacitance C of parallel connection_{p}With resonant inductance L_{p}, and two
The sys node of person is as the input of former limit resonant network, and the first outfan of described high-frequency inversion network is by described auxiliary
Inductance L_{1}Being connected with the input of described former limit resonant network, the second outfan of described high-frequency inversion network is humorous with described former limit
Another input of vibrating network is connected.
Alternatively preferred technical scheme, described first switch S1, second switch S2, the 3rd switch S3 and the 4th
Switch S4 can be selected for IGBT insulated gate bipolar transistor.
Further, (1) system operating frequency is met more than ZVS frequency, i.e. f when simultaneously_{s}＞ f_{ZVS}；(2) all switching tubes
Need at t_{1}～t_{3}Time period in turn off；And (3) are at overlapping conducting time T_{OV}Stage, auxiliary induction L_{1}On electric currentMust
Must be more than filter inductance L_{dc}On electric current these three under the conditions of, be divided into following mode during described circulation control circuit stable state:
Mode 0: at t_{0}Before moment, auxiliary induction L_{1}On electric currentUnidirectional current equal to the output of described quasi-current source
i_{in_dc}Negative value, i.e.Resonant capacitor voltageFor negative value, second switch S2, the 3rd switch S3 are on
State, the first switch S1, the 4th switch S4 are off state, filter inductance L_{dc}On electric current by second switch S2, the 3rd
Switch S3 and former limit resonant network constitute primary Ioops；
Mode 1:t_{0}～t_{1}Time period, t_{0}Moment first switchs S1 and the 4th switch S4 conducting, auxiliary induction L_{1}On electric currentAt resonant capacitor voltageEffect under just become from negative, until at t_{1}Moment is equal to i_{in_dc}, at electric currentFor time negative, lead to
Cross second switch S2-diode D4, the 3rd switch S3-diode D1 forms loop, at electric currentBecome timing, open by first
Close S1-diode D3, the 4th switch S4-diode D2 forms loop, and circulation first is switching S1, second switch S2, the 3rd opening
Close in the loop that S3 and the 4th switch S4 is constituted and flow, in this mode, filter inductance L_{dc}On electric current directly by first switch
S1-second switch S2, the 3rd switch S3-the 4th switch S4 constitute loop, without former limit resonant network；
Mode 2:t_{1}～(t_{1}+T_{OV}) time period, t_{1}Moment resonant capacitor voltageIt is still negative value, electric currentContinue to increase,
t_{2}Moment isZero crossing, now, electric currentReach maximum, afterwards, electric currentStart to reduce, in this mode, circulation
Flow, at t in the loop that first switch S1-the 4th switch S4 is constituted_{1}+T_{OV}In the moment, second switch S2 and the 3rd switch S3 closes
Disconnected, in this mode, filter inductance L_{dc}On electric current directly by first switch S1-second switch S2, the 3rd switch S3-the 4th
Switch S4 constitutes loop, without former limit resonant network；
Mode 3:(t_{1}+T_{OV})～t_{3}Time period, in this mode, second switch S2 and the 3rd switch S3 turns off, and circulation exists
Flow in the loop that first switch S1-diode D3, the 4th switch S4-diode D2 are constituted, originally second switch S2, the 3rd
In switch S3, the electric current of flowing has been transferred to the diode D2 of its correspondence, diode D3 so that second switch S2, the 3rd switch S3
Carving voltage when off is approximation 0, it is achieved that ZVS, in this mode, and filter inductance L_{dc}On electric current by the first switch S1, the
Four switch S4 and former limit resonant network constitute loop, electric current i_{L1}For the electric current on filter inductance and loop current sum, at t_{3}Time
Carve, electric current i_{L1}Unidirectional current i equal to the output of described quasi-current source_{in_dc}, loop current reduces to 0, and circulation flow path no longer exists, ring
Stream disappears；
Mode 4:t_{3}～t_{4}Time period, the first switch S1 and the 4th switch S4 are in the conduction state, second switch S2 and the 3rd
Switch S3 is off state, filter inductance L_{dc}On electric current by the first switch S1, second switch S2 and former limit Resonance Neural Network
Network constitutes primary Ioops；
t_{4}～t_{5}Time period is the lower half cycle of this circulation control circuit, corresponding, the first switch, the 4th switch are turning off
Shi Shixian ZVS.
Compared with prior art, the technical scheme that the application provides, the technique effect or the advantage that have be: reduces circulation
Peak value, it is possible to realize approximation zero current turning-on, zero voltage turn-off, reduce switching tube spoilage.
Embodiment
A kind of induction electric energy based on auxiliary induction transmission circulation control circuit system, as it is shown in figure 1, include by connecting
DC source E_{in}With filter inductance L_{dc}Composition quasi-current source, pulse generating circuit, high-frequency inversion network, former limit resonant network,
Secondary resonant network, rectifying and wave-filtering network and load, wherein, described quasi-current source is connected with described high-frequency inversion network, for institute
Stating high-frequency inversion network and provide unidirectional current, described pulse generating circuit is connected with described high-frequency inversion network, output control pulse
Controlling the output waveform of described high-frequency inversion network, described high-frequency inversion network is connected with described former limit resonant network, output
Square wave current gives described former limit resonant network, and described secondary resonant network receives the sinusoidal electricity of described former limit resonant network output
Stream, described secondary resonant network by described rectifying and wave-filtering network with load be connected, by sinusoidal current after rectifying and wave-filtering defeated
Going out to load, described high-frequency inversion network includes the first switch S1, second switch S2, the 3rd switch S3 and the 4th switch S4,
It is provided with an auxiliary induction L between outfan and the described former limit resonant network of described high-frequency inversion network_{1}, for damping ring
The rate of climb of stream and peak value, and in each PWM cycle of pulse generating circuit, all there is described first switch S1, second open
Close S2, the 3rd switch S3 and the 4th switchs the time T that S4 simultaneously turns on_{OV}, i.e. the overlapping conducting time, on the one hand give filter inductance
L_{dc}There is provided current loop, on the other hand so that auxiliary induction L_{1}On electric current steadily commutate (from+i_{in_dc}It is converted into-i_{in_dc}, or
Person is from-i_{in_dc}It is converted into+i_{in_dc})。
Wherein, described first switch S1 includes MOSFET pipe Q1 and antiparallel diode D1, described second switch S2 bag
Include MOSFET pipe Q2 and antiparallel diode D2, described 3rd switch S3 and include MOSFET pipe Q3 and antiparallel diode
D3, described 4th switch S4 include MOSFET pipe Q4 and antiparallel diode D4, wherein, the source electrode of described MOSFET pipe Q1 with
The drain electrode of described MOSFET pipe Q2 connects, and the source electrode of described MOSFET pipe Q3 is connected with the drain electrode of described MOSFET pipe Q4, described
The drain electrode of MOSFET pipe Q1 is connected with the drain electrode of described MOSFET pipe Q3, and the source electrode of described MOSFET pipe Q1 is managed with described MOSFET
The drain electrode of Q4 connects, the positive pole of all diodes all with the source electrode connection of corresponding MOSFET pipe, the negative pole of all diodes all with
The drain electrode of corresponding MOSFET pipe connects, and the grid of described MOSFET pipe is all connected with described pulse generating circuit, described MOSFET
The source electrode of pipe Q1 is as the first outfan of described high-frequency inversion network, and the source electrode of described MOSFET pipe Q3 is inverse as described high frequency
Becoming the second outfan of network, described former limit resonant network includes the resonant capacitance C of parallel connection_{p}With resonant inductance L_{p}, and both are also
Interlink point passes through described auxiliary induction L as the input of former limit resonant network, the first outfan of described high-frequency inversion network_{1}
It is connected with the input of described former limit resonant network, the second outfan of described high-frequency inversion network and described former limit resonant network
Another input be connected.
The oscillogram of system when Fig. 2 show stable state, Fig. 3 (a), Fig. 3 (b), Fig. 3 (c), Fig. 3 (d), Fig. 3 (e) are respectively
The equivalent circuit diagram of each mode during stable state.
Mode 0: at t_{0}Before moment, auxiliary induction L_{1}On electric currentUnidirectional current equal to the output of described quasi-current source
i_{in_dc}Negative value, i.e.Resonant capacitor voltageFor negative value, second switch S2, the 3rd switch S3 are on
State, the first switch S1, the 4th switch S4 are off state, filter inductance L_{dc}On electric current by second switch S2, the 3rd
Switch S3 and former limit resonant network constitute primary Ioops；
Mode 1:t_{0}-t_{1}Time period, t_{0}Moment first switchs S1 and the 4th switch S4 conducting, auxiliary induction L_{1}On electric currentAt resonant capacitor voltageEffect under just become from negative, until at t_{1}Moment is equal to i_{in_dc}, at electric currentFor time negative, lead to
Cross second switch S2-diode D4, the 3rd switch S3-diode D1 forms loop, at electric currentBecome timing, open by first
Close S1-diode D3, the 4th switch S4-diode D2 forms loop, and owing in MOSFET, electric current can be with two-way flow, and it is led
Logical pressure drop is generally below its body diode, therefore circulation switchs S1, second switch S2, the 3rd switch S3 and the 4th switch S4 first
Flow in the loop constituted, in this mode, filter inductance L_{dc}On electric current directly by the first switch S1-second switch S2, the
Three switch S3-the 4th switch S4 constitute loop, without former limit resonant network；
Mode 2:t_{1}-(t_{1}+T_{OV}) time period, t_{1}Moment resonant capacitor voltageIt is still negative value, electric currentContinue to increase, t_{2}
Moment isZero crossing, now, electric currentReach maximum, afterwards, electric currentStarting to reduce, in this mode, circulation exists
Flow, at t in the loop that first switch S1-the 4th switch S4 is constituted_{1}+T_{OV}In the moment, second switch S2 and the 3rd switch S3 turns off,
In this mode, filter inductance L_{dc}On electric current directly by first switch S1-second switch S2, the 3rd switch S3-the 4th open
Close S4 and constitute loop, without former limit resonant network；
Mode 3:(t_{1}+T_{OV})-t_{3}Time period, in this mode, second switch S2 and the 3rd switch S3 turns off, and circulation is the
Flow in the loop that one switch S1-diode D3, the 4th switch S4-diode D2 are constituted, originally at second switch S2, the 3rd open
Close the electric current of flowing in S3 and be transferred to the diode D2 of its correspondence, diode D3 so that second switch S2, the 3rd switch S3 exist
Turning off moment voltage is approximation 0, it is achieved that ZVS, in this mode, and filter inductance L_{dc}On electric current by first switch S1, the 4th
Switch S4 and former limit resonant network constitute loop, electric currentFor the electric current on filter inductance and loop current sum, at t_{3}Moment,
Electric currentUnidirectional current i equal to the output of described quasi-current source_{in_dc}, loop current reduces to 0, and circulation flow path no longer exists, and circulation disappears
Lose；
Mode 4:t_{3}-t_{4}Time period, the first switch S1 and the 4th switch S4 are in the conduction state, second switch S2 and the 3rd
Switch S3 is off state, filter inductance L_{dc}On electric current by the first switch S1, second switch S2 and former limit Resonance Neural Network
Network constitutes primary Ioops；
t_{4}-t_{5}Time period is the lower half cycle of this circulation control circuit, corresponding, the first switch, the 4th switch are when off
Realize ZVS.
Knowable to the analysis of each mode above, it is achieved the condition of above-mentioned mode of operation has a three below:
(1) if owing to this main circuit suppresses first kind circulation, so, system operating frequency is more than ZVS frequency, i.e. f_{s}＞
f_{ZVS}；(2) all switching tubes need at t_{1}～t_{3}Turn off in time period, i.e. overlapping conducting time T_{OV}Have certain limitations.If switch
Pipe is at t_{1}Front shutoff, due to i_{L1}Less than i_{in_dc}, auxiliary induction L_{1}Upper electric current i_{L1}To improve within a very short time to i_{in_dc}, produce
Due to voltage spikes can add to turn off switching tube two ends, may damage switching tube；
(3) at overlapping conducting time T_{OV}Stage, auxiliary induction L_{1}On electric current i_{L1}Have to be larger than filter inductance L_{dc}On electricity
Stream, otherwise cannot realize ZVS and turn off.As auxiliary induction L_{1}Electric current i_{L1}At overlapping conducting time T_{OV}Inside it is consistently less than i_{in_dc}Time,
The most there is not t_{1}～t_{3}In this stage, this just will necessarily produce the highest due to voltage spikes.
When above three condition all meets, circulation amplitude is suppressed, and four switching tubes all can realize ZVS and turn off.
Due in IPT system, the most former and deputy limit equal approximate resonance of resonant network, and Q-value is higher.Therefore, at weight
Folded ON time T_{OV}In, can be by former limit parallel resonance electric capacity C_{p}It is approximately an alternating-current voltage source.Its voltage expression is:
Fig. 4 is circulation equivalent circuit diagram in overlapping ON time, can list following formula
$\begin{array}{c}{U}_{{L}_{1}}\left(t\right)=-{U}_{{C}_{P}}\left(t\right)={L}_{1}\frac{{\mathrm{di}}_{{L}_{1}}\left(t\right)}{dt}\\ {i}_{{L}_{1}}\left(t\right)={\∫}_{{t}_{0}}^{t}\frac{-{U}_{{C}_{P}}\left(t\right)}{{L}_{1}}\·dt-{i}_{in\_dc}={U}_{{C}_{P}\_peak}\frac{\mathrm{cos}(\mathrm{\ω}t-{\mathrm{\ωt}}_{2})-\mathrm{cos}(-{\mathrm{\ωt}}_{2})}{{\mathrm{\ωL}}_{1}}-{i}_{in\_dc}\end{array}---\left(2\right)$
At t_{2}Moment,i_{L1}Reach peak value:
${i}_{{L}_{1}\_peak}={i}_{{L}_{1}}\left({t}_{2}\right)={U}_{{C}_{P}\_peak}\frac{1-\mathrm{cos}(-{\mathrm{\ωt}}_{2})}{{\mathrm{\ωL}}_{1}}-{i}_{in\_dc}---\left(3\right)$
From condition (3), i_{L1_peak}Have to be larger than i_{in_dc}, from formula (3), reduce L_{1}Size, can directly increase
Big i_{L1_peak}.Therefore, it can by suitably choosing L_{1}Value meet condition (3).
One important feature of this circulation control circuit is constant voltage no-load voltage ratio.Circuit diagram 5 show circulation control circuit
Input, output waveform figure, when system reaches stable state, power supply input power is:
The output of high-frequency inversion network is:
$\begin{array}{c}{P}_{inv\_out}=\frac{2}{T}{\∫}_{\mathrm{\θ}1}^{\mathrm{\θ}2}{i}_{in\_dc}{U}_{inv\_out\_peak}\mathrm{sin}\mathrm{\ω}t\·dt\\ =\frac{1}{\mathrm{\π}}{\∫}_{\mathrm{\θ}1}^{\mathrm{\θ}2}{i}_{in\_dc}{U}_{inv\_peak}\mathrm{sin}\mathrm{\θ}\·d\mathrm{\θ}=\frac{1}{\mathrm{\π}}{i}_{in\_dc}\·(-{U}_{inv\_out\_peak}\mathrm{cos}\mathrm{\θ}{|}_{\mathrm{\θ}1}^{\mathrm{\θ}2})\\ =\frac{1}{\mathrm{\π}}{i}_{in\_dc}{U}_{inv\_out\_peak}\·({\mathrm{cos\θ}}_{1}+\mathrm{cos}(\mathrm{\π}-{\mathrm{\θ}}_{2}\left)\right)\end{array}---\left(5\right)$
θ in formula_{1}、θ_{2}The initial phase angle being not zero for half period medium-high frequency inversion network output voltage and end phase angle, with
Resonant capacitor voltagePhase angle is reference.
Ignore the loss of high-frequency inversion network breaker in middle pipe, L_{dc}Loss, then the output of high-frequency inversion network is with straight
Stream power supply input power is equal.
$\begin{array}{c}{P}_{\mathrm{sup}ple\_in}={P}_{inv\_out}\\ {U}_{inv\_out\_peak}={E}_{in}\frac{\mathrm{\π}}{({\mathrm{cos\θ}}_{1}+\mathrm{cos}(\mathrm{\π}-{\mathrm{\θ}}_{2}\left)\right)}\end{array}---\left(6\right)$
At [θ_{1},π-θ_{2}Time between], high-frequency inversion net output voltage is directly output to resonant capacitance two ends.It is also contemplated that
θ_{1}、π-θ_{2}Less, therefore typically have following formula to set up:
U_{Cp_peak}=U_{inv_out_peak} (7)
To auxiliary induction L_{1}For former limit resonant network below, owing to former limit resonant network is near resonant frequency,
Its energy is the overwhelming majority transmitted by first-harmonic, and therefore, the input power of former limit resonant network is expressed as:
${P}_{res\_in}=\frac{{\left({U}_{Cp\_peak}\right)}^{2}}{2\left|{Z}_{parallel}\right|}cos\mathrm{\θ}---\left(8\right)$
In formula (8), θ is resonant network input impedance angle, is alsoAnd i_{L1}Fundamental harmonic wave between phase contrast,
Z_{parallel}It it is the total impedance (series resonant network of secondary use herein) of former limit resonant network and late-class circuit thereof.
${Z}_{parallel}=({\mathrm{j\ωL}}_{P}+\frac{{\mathrm{\ω}}^{2}{M}^{2}}{{\mathrm{j\ωL}}_{S}+\frac{1}{{\mathrm{j\ωC}}_{S}}+{R}_{L\_eq}})//\frac{1}{{\mathrm{j\ωC}}_{S}}=\frac{1}{\frac{1}{({\mathrm{j\ωL}}_{P}+\frac{{\mathrm{\ω}}^{2}{M}^{2}}{{\mathrm{j\ωL}}_{S}+\frac{1}{{\mathrm{j\ωC}}_{S}}+{R}_{L\_eq}})}+{\mathrm{j\ωC}}_{S}}$
In formula (9)
Convolution (6), (7), (8), the input power of resonant network is:
${P}_{res\_in}=\frac{{\mathrm{\π}}^{2}{E}_{in}^{2}}{2{({\mathrm{cos\θ}}_{1}+\mathrm{cos}(\mathrm{\π}-{\mathrm{\θ}}_{2}\left)\right)}^{2}}\·\frac{\mathrm{cos}\mathrm{\θ}}{\left|{Z}_{parallel}\right|}---\left(10\right)$
In real system, due to L in real system_{1}The least, t_{0}～t_{3}Time period accounts for the least of whole cycle
Point, therefore θ_{1}、π-θ_{2}For the whole cycle the least, can ignore, then (10) formula can be reduced to:
${P}_{res\_in}\≈\frac{{\mathrm{\π}}^{2}{E}_{in}^{2}}{8}\·\frac{cos\mathrm{\θ}}{\left|{Z}_{parallel}\right|}---\left(11\right)$
Ignore L_{dc}、L_{1}With the loss on each switching tube, the most former limit resonant network input power is equal with power supply input power.
${E}_{in}{i}_{in\_dc}=\frac{{\mathrm{\π}}^{2}{E}_{in}^{2}}{8}\·\frac{cos\mathrm{\θ}}{\left|{Z}_{parallel}\right|}---\left(12\right)$
Therefore,
Next the voltage change ratio of lower whole system will be analyzed.For high-frequency inversion network, its voltage change ratio is:
${M}_{1}=\frac{{U}_{inv\_out\_peak}}{{E}_{in}}=\frac{\mathrm{\π}}{({\mathrm{cos\θ}}_{1}+\mathrm{cos}(\mathrm{\π}-{\mathrm{\θ}}_{2}\left)\right)}---\left(14\right)$
Due to θ_{1}、π-θ_{2}It is all higher than 0, but value is less, typically has 1 ＜ (cos θ_{1}+cos(π-θ_{2})) ＜ 2, therefore, high frequency is inverse
The voltage change ratio becoming network only changes in smaller range.
For former limit in parallel resonant network, its voltage change ratio is
${M}_{2}=\frac{{U}_{{R}_{L}}}{{U}_{inv\_out\_peak}}=\frac{j\mathrm{\ω}M}{({\mathrm{j\ωL}}_{p}+{R}_{{L}_{p}})+\frac{({\mathrm{j\ωL}}_{p}+{R}_{{L}_{p}})({\mathrm{j\ωL}}_{s}+{R}_{{L}_{s}}+\frac{1}{{\mathrm{j\ωC}}_{s}})+{\mathrm{\ω}}^{2}{M}^{2}}{{R}_{L}}}---\left(15\right)$
As load R_{L}Relatively big andWhen can ignore, (15) formula can abbreviation be
${M}_{2}\≈\frac{j\mathrm{\ω}M}{({\mathrm{j\ωL}}_{p}+{R}_{{L}_{p}})}\≈\frac{M}{{L}_{p}}---\left(16\right)$
Now M_{2}No longer change, approximately constant with frequency and the change of load.
Then the voltage change ratio of whole system is
${M}_{sys}={M}_{1}{M}_{2}\≈\frac{\mathrm{\π}}{({\mathrm{cos\θ}}_{1}+\mathrm{cos}(\mathrm{\π}-{\mathrm{\θ}}_{2}\left)\right)}\frac{M}{{L}_{p}}---\left(17\right)$
Consider further that θ_{1}、π-θ_{2}For the whole cycle the least, can ignore, then the voltage change ratio of whole system is:
${M}_{sys}\≈\frac{\mathrm{\π}}{2}\frac{M}{{L}_{p}}---\left(18\right)$
By formula (18) it can be seen that the voltage change ratio of this system is when loading value and being bigger, basic with load and frequency without
Close.Therefore, constant voltage no-load voltage ratio is one critically important feature of this system, in the occasion that some is the highest to voltage request, and can not
Need to add extra voltage regulator, it becomes possible to realize the output of metastable voltage.And this system to operating frequency also without
Requirement, when conversion frequency, system output characteristics is without significant change, during real system work, can be by selecting suitable work
Working frequency, makes working state of system reach optimum.
Selecting in terms of switching tube, need this circuit is opened switch tube voltage, current stress and switch, shutoff moment
State is analyzed.
The symmetry run in view of system in the cycle, the voltage of some switching tube derived, current stress
It is the voltage of four switching tubes, current stress.Mainly for t_{0}～t_{4}Time period is analyzed.
Switching tube S2, S3 are at t_{3}～t_{4}Stage is off state, and bears forward voltage.The drain-source of its switching tube
The voltage that two ends are born is equal toSo the maximum voltage that switching tube drain-source two ends are born isThis value
Can be determined by formula (6), (7).
Switching tube S1, S4 are at t_{0}～t_{4}Time period is on the stage all the time, in non-overlapped conducting phase t_{3}～t_{4}, on it
The electric current flow through is i_{in_dc}。
At overlapping conducting stage t_{0}～t_{3}, the electric current that all switching tubes flow through is synthesized by two parts electric current, and Part I is
L_{dc}On electric current, owing to this stage all switching tubes are both turned on, so current uniform, the electric current that all switching tubes flow through isPart II is L_{1}On electric current, the first switching tube S1, the 4th switching tube S4 upstream overcurrent areSecond switch
Pipe S2, the 3rd switching tube S3 upstream overcurrent are
To sum up, in the overlapping conducting stage, the electric current that the first switching tube S1, the 4th switching tube S4 flow through isThe
The electric current flow through on two switching tube S2, the 3rd switching tube S3 is
The maximum of the electric current then flow through on the first switching tube S1, the 4th switching tube S4 isBut due toValue cannot accurately calculate, therefore current stress cannot determine in advance, can only rely on experimental data.
Further, when selecting switching tube, also need to consider practical devices current changing rateRestriction.Because leading in overlap
Logical stage current rate of change is relatively big, may be beyond the maximum current slew rate of some devices.
First switching tube S1, the 4th switching tube S4 are at t_{0}Moment is open-minded, and after opening, the electric current that it flows through isDue to nowEqual to-i_{in_dc}, it is possible to realize zero current turning-on characteristic.
Second switch pipe S2, the 3rd switching tube S3 are at t_{3}Moment turns off, and has no progeny in pass, and its anti-paralleled diode turns on, therefore,
It is capable of zero voltage turn-off characteristic.
In sum, the first switch S1, second switch S2, the 3rd switch S3 and the 4th switch S4 are capable of zero current and open
Logical, zero voltage turn-off characteristic.
Alternatively preferred technical scheme, described first switch S1, second switch S2, the 3rd switch S3 and the 4th
Switch S4 can be selected for IGBT insulated gate bipolar transistor, because the characteristic of its zero voltage turn-off, when can eliminate IGBT shutoff
Current tail phenomenon.
In above-described embodiment of the application, by providing a kind of induction electric energy based on auxiliary induction transmission circulation to control electricity
Road system, is provided with an auxiliary induction L between the outfan and described former limit resonant network of described high-frequency inversion network_{1},
For damping the rate of climb and the peak value of circulation, and in each PWM cycle of pulse generating circuit, all have described first open
Close the time T that S1, second switch S2, the 3rd switch S3 and the 4th switch S4 simultaneously turn on_{OV}, i.e. the overlapping conducting time, on the one hand
To filter inductance L_{dc}There is provided current loop, on the other hand so that auxiliary induction L_{1}On electric current steadily commutate, this system realizes near
Like zero current turning-on, zero voltage turn-off, reduce circulation peak value, reduce the switching loss of switching tube, it is suppressed that resonant network
And the bigger circulation between inversion network.
It should be pointed out that, described above is not limitation of the present invention, the present invention is also not limited to the example above,
Change, modification that those skilled in the art are made in the essential scope of the present invention, add or replace, also should
Belong to protection scope of the present invention.