CN108494256A - A kind of the LLC resonant converter underloading voltage modulation system and modulation strategy of energy feedback - Google Patents
A kind of the LLC resonant converter underloading voltage modulation system and modulation strategy of energy feedback Download PDFInfo
- Publication number
- CN108494256A CN108494256A CN201810215315.6A CN201810215315A CN108494256A CN 108494256 A CN108494256 A CN 108494256A CN 201810215315 A CN201810215315 A CN 201810215315A CN 108494256 A CN108494256 A CN 108494256A
- Authority
- CN
- China
- Prior art keywords
- voltage
- synchronous rectifier
- output
- power tube
- output voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
- H02M3/33592—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
Include power supply, semi-bridge alternation circuit, resonant network resistance, high frequency transformer, current-doubling rectifier and output loading the invention discloses a kind of LLC resonant converter of energy feedback underloading voltage modulation system and modulation strategy, the system；The strategy utilizes the structure of high frequency transformer secondary side synchronous rectifier, when system is operated at light load, by the phase shifting angle for adjusting high frequency transformer primary side power tube and secondary side synchronous rectifier, make output capacitance to mains side feedback energy, underloading output voltage is reduced to reach, while making output voltage stabilization in rated voltage according to system input and output voltage relationship.The present invention solves the problems, such as that the lower output voltage pump of LLC resonant converter underloading rises by modulation strategy, stabilize output voltage, without increasing hardware cost, and the problems such as efficiency reduces, application range is limited, output voltage ripple is big is not present, there is larger foreground in commercial Application.
Description
Technical field
The present invention relates to LLC resonant converter technical field more particularly to a kind of LLC resonant converter of energy feedback are light
Carry voltage modulation system and modulation strategy.
Background technology
The one kind of LLC converters as process resonance converter, because its voltage regulation limits is wide, efficient, outlet side without
The advantages that needing filter inductance and be widely used in communicate voltage, battery charging etc. DC convertings field.But due to transformer and
The reason of parasitic capacitance of power tube and load cutout, LLC converters, which have output voltage pump at light load and rise, to be difficult to adjust
Problem, this causes underloading downconverter closed-loop control to become unstable, and the pressure resistance of power tube needs to choose the surplus of bigger, load
Since voltage is damaged higher than rated value, these problems are brought greatly to converter design, stable operation and power supply reliability
Challenge.Presently, there are research method can adjust the lower output voltage of underloading and make its reduction, but there are efficiency to reduce, applies
The shortcomings of occasion is limited, hardware cost is high, output voltage ripple increases.Therefore, the voltage modulated of the lower LLC converters of research underloading
Method is of great significance.
For underloading voltage pump rise problem, traditional LLC controlled resonant converter is there are mainly two types of solution, and one is from parameter
Low start voltage drops in terms of design, topological structure optimization, but there are less efficient, hardware realization is difficult, cost for these methods
The problems such as increase；Another kind is to drop low start voltage by different control strategies, is mainly had at present by adjusting frequency, adjusting
Duty ratio is solved using modes such as intermittent regulation and control, these methods, which have that loss is big and output voltage ripple becomes larger, etc. lacks
Point.
Invention content
The technical problem to be solved in the present invention is for existing in the prior art that loss is big and output voltage ripple is big
Defect provides a kind of the LLC resonant converter underloading voltage modulation system and modulation strategy of energy feedback.
The technical solution adopted by the present invention to solve the technical problems is：
The present invention provides a kind of LLC resonant converter underloading voltage modulation system of energy feedback, including power supply, half bridging
Change circuit, resonant network resistance, high frequency transformer, current-doubling rectifier and output loading；Wherein：
Semi-bridge alternation circuit includes the first power tube and the second power tube being connected in series with；First work(of semi-bridge alternation circuit
The drain of rate pipe is connected with positive pole, and the source level of the second power tube is connected with power cathode；Resonant network resistance includes resonance
Capacitance, resonant inductance and high frequency transformer, resonant capacitance one end are connected with the midpoint of semi-bridge alternation circuit, the other end and resonance electricity
Sense is connected after being connected in series with high frequency transformer first side winding, the other end and power cathode of high frequency transformer first side winding
It is connected；The first synchronous rectifier and the second synchronous rectifier are provided in current-doubling rectifier；The secondary side of high frequency transformer is adopted
With band centre cap structure, centre cap is connected with the cathode at output loading end, and secondary side both ends are synchronous with first whole respectively
Flow tube is connected with the source level of the second synchronous rectifier；The drain electrode of first synchronous rectifier and the second synchronous rectifier is connected in parallel simultaneously
It is connected with output capacitance and the anode of output loading.
Further, it is additionally provided with high frequency transformer magnetizing inductance in resonant network resistance of the invention, it is resonant inductance, humorous
It shakes capacitance and high frequency transformer magnetizing inductance is sequentially connected.
The present invention provides a kind of LLC resonant converter underloading voltage modulated strategy of energy feedback, including following work shape
State：
When LLC resonant converter underloading voltage modulation system normal work, detection output voltage is compared with given voltage
Compared with as a result feeding controller generates control instruction, then generates switching frequency regulating command through voltage-frequency conversion links, controls converter
First power tube and the second power tube switching frequency, to adjust output voltage to given voltage, system is provided to output loading
Energy；
When LLC resonant converter underloading voltage modulation system is operated at light load, system enters energy feedback pattern, adjusts
Phase shifting angle between first power tube and the second power tube and the first synchronous rectifier and the second synchronous rectifier, control output electricity
Hold to input side and release energy, to reduce output voltage amplitude.
Further, the strategy of the invention further includes following working condition：
When load lightens, system is operated in maximum switching frequency, and by several switch periods, output voltage rises, on
It is raised to certain valve system and enters energy feedback pattern, when output voltage is more than given value, the first synchronous rectification is adjusted by PI
Pipe and the second synchronous rectifier increase phase shifting angle, accelerate capacitive energy to input feedback, to reduce rapidly output voltage；
When output voltage declines, then the first synchronous rectifier and the second synchronous rectifier are adjusted by PI, reduces phase shift
Angle reduces capacitive energy to input feedback, to improve output voltage.
Further, the input and output voltage relationship of LLC resonant converter of the invention underloading voltage modulation system is：
Wherein, V2For output voltage amplitude, V1For input voltage amplitude, RoFor output loading, Lr is resonant inductance, and Cr is
Resonant capacitance, ω are angular frequency,For phase shifting angle, output voltage is by input voltage, resonant inductance and capacitance, load and secondary side
The influence of phase shifting angle.
Further, the high frequency of voltage modulation system is lightly loaded in the strategy of the invention by adjusting LLC resonant converter
The angle of flow of Circuit Fault on Secondary Transformer synchronous rectifier makes it be ahead of primary side power tube, and output power is made to be transmitted to from load-side
Mains side, to adjust output voltage；LLC resonant converter is lightly loaded 6 stages of voltage modulation system circuit mode point：
The S1 stages：Moment is t0-t1；
When the t0 moment, the second power tube shutdown, the output capacitance at the second power tube both ends is charged by resonance current, and first
The output capacitance at power tube both ends is discharged, and bridge arm mid-point voltage is caused constantly to increase；Due to resonance and excitation inductance current
Amplitude it is unequal, therefore high frequency transformer secondary side flows through electric current；Since the pulse signal of the first synchronous rectifier is in this rank
It arrives before section, therefore the first power tube flows through electric current, before this body diode conducting of the second power tube, not due to electric current
It is reduced to 0, therefore continues to be connected；The first synchronous rectifier and the second synchronous rectifier simultaneously turn at this time, therefore high frequency transformation
Device both end voltage is 0；This stage output capacitance is discharged to mains side；
The S2 stages：Moment is t1-t2；
When the t1 moment, the output capacitance at the first power tube and the second power tube both ends completes charge and discharge, therefore the first work(
The electric current that the body diode of rate pipe passes through resonant network；The state of resonant network resistance and current-doubling rectifier and S1 stage phases
Together；First synchronous rectifier by electric current continuously increase, the body diode of the second synchronous rectifier by electric current
It is continuous to reduce；
The S3 stages：Moment is t2-t3；
When the t2 moment, the electric current for flowing through the body diode of the second synchronous rectifier is reduced to 0, and outlet side only has first same
Walk rectifying tube conducting, output capacitance is discharged feedback energy to mains side, the state of semi-bridge alternation circuit and resonant network resistance with
The S2 stages are identical；High frequency transformer both end voltage is maintained at positive output voltage, therefore the amplitude of excitation and resonance inductive current
It is gradually decreased as 0 by negative value；
The S4 stages：Moment is t3-t4；
When the t3 moment, resonance and excitation inductance current is equal and amplitude is 0, hereafter its value increases to positive value, and encourages
Magnetoelectricity sense amplitude is more than resonant inductance；The body diode of first power tube turns off, and primary current flows through first power tube itself；Two
Secondary side electric current outflow transformer Same Name of Ends is charged by the body diode of the first synchronous rectifier to output capacitance, and output electricity is caused
Pressure increases；
The S5 stages：Moment is t4-t5；
When the t4 moment, the shutdown of the first synchronous rectifier causes synchronous rectification state to disappear, but does not influence semi-bridge alternation electricity
The operating status on road and resonant network resistance；
The S6 stages：Moment is t5-t6；
When the t5 moment, the pulse signal arrival of the second synchronous rectifier turns it on, then some electric current flows through, but
Numerical value is less than the electric current for the body diode for flowing through the first synchronous rectifier, therefore another part current direction loads；Until first
Synchronous rectifier and the second synchronous rectifier change of current are completed, and half of switch periods terminates, into NextState.
The beneficial effect comprise that：The LLC resonant converter underloading voltage modulated system of the energy feedback of the present invention
System and strategy solve the problems, such as that the lower output voltage pump of LLC resonant converter underloading rises by control strategy, stabilize output electricity
Without increasing hardware cost, and the problems such as efficiency reduces, application range is limited, output voltage ripple is big is not present, in industry in pressure
Using above there is larger foreground.
Description of the drawings
Present invention will be further explained below with reference to the attached drawings and examples, in attached drawing：
Fig. 1 is the circuit diagram of the embodiment of the present invention；
Fig. 2 is the synchronous rectification underloading phase shifting control modulation waveform schematic diagram of the embodiment of the present invention；
Fig. 3 is the voltage gain analysis circuit figure of the embodiment of the present invention；
Fig. 4 (a) is the underloading circuit for regulating and controlling operation mode figure (a) of the embodiment of the present invention；
Fig. 4 (b) is the underloading circuit for regulating and controlling operation mode figure (b) of the embodiment of the present invention；
Fig. 4 (c) is the underloading circuit for regulating and controlling operation mode figure (c) of the embodiment of the present invention；
Fig. 4 (d) is the underloading circuit for regulating and controlling operation mode figure (d) of the embodiment of the present invention；
Fig. 4 (e) is the underloading circuit for regulating and controlling operation mode figure (e) of the embodiment of the present invention；
Fig. 4 (f) is the underloading circuit for regulating and controlling operation mode figure (f) of the embodiment of the present invention；
Fig. 5 is the underloading regulating and controlling voltage realization method of the embodiment of the present invention；
In figure：The first power tubes of Q1-, the second power tubes of Q2-, the first synchronous rectifiers of Q3-, the second synchronous rectifiers of Q4-,
VinInput power, Tr- high frequency transformers, Lr- resonant inductances, Cr- resonant capacitances, Lm- magnetizing inductances, C0Capacitance, RoOutput
Load, VprPrimary side port voltage, VseSecondary port voltage, ω-angular frequency,Phase shifting angle, f- working frequencies, Vr- give
Definite value；fmaxMaximum switching frequency, the conversion of VOF voltage-frequency.
Specific implementation mode
In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that described herein, specific examples are only used to explain the present invention, not
For limiting the present invention.
As shown in Figure 1, the LLC resonant converter of the energy feedback of the embodiment of the present invention is lightly loaded voltage modulation system, including
Power supply, semi-bridge alternation circuit, resonant network resistance, high frequency transformer, current-doubling rectifier and output loading；Wherein：
Semi-bridge alternation circuit includes the first power tube Q1 and the second power tube Q2 being connected in series with；The of semi-bridge alternation circuit
The drain of one power tube Q1 is connected with positive pole, and the source level of the second power tube Q2 is connected with power cathode；Resonant network resistance
Including resonant capacitance Cr, resonant inductance Lr and high frequency transformer Tr, the midpoint phase of the one end resonant capacitance Cr and semi-bridge alternation circuit
Even, it is connected with high frequency transformer Tr first side windings after the other end is connected in series with resonant inductance Lr, high frequency transformer Tr is primary
The other end of side winding is connected with power cathode；Be provided in current-doubling rectifier the first synchronous rectifier Q3 and second synchronize it is whole
Flow tube Q4；The secondary side of high frequency transformer Tr uses band centre cap structure, the cathode phase of centre cap and output loading end
Even, secondary side both ends are connected with the source level of the first synchronous rectifier Q3 and the second synchronous rectifier Q4 respectively；First synchronous rectification
The drain electrode of pipe Q3 and the second synchronous rectifier Q4 be connected in parallel and with output capacitance CoIt is connected with the anode of output loading.
High frequency transformer magnetizing inductance Lm, resonant inductance Lr, resonant capacitance Cr and height are additionally provided in resonant network resistance
Frequency power transformer magnetizing inductance Lm is sequentially connected.
The LLC resonant converter of energy feedback is lightly loaded voltage modulated strategy, including following working condition：
When LLC resonant converter underloading voltage modulation system normal work, detection output voltage is compared with given voltage
Compared with as a result feeding controller generates control instruction, then generates switching frequency regulating command through voltage-frequency conversion links, controls converter
First power tube Q1 and the second power tube Q2 switching frequencies, to adjust output voltage to given voltage, system is to output loading
Energy is provided；
When LLC resonant converter underloading voltage modulation system is operated at light load, system enters energy feedback pattern, adjusts
Phase shifting angle between first power tube Q1 and the second power tube Q2 and the first synchronous rectifier Q3 and the second synchronous rectifier Q4, control
Output capacitance C processedoIt releases energy to input side, to reduce output voltage amplitude.
The strategy further includes following working condition：
When load lightens, system is operated in maximum switching frequency, and by several switch periods, output voltage rises, on
It is raised to certain valve system and enters energy feedback pattern, when output voltage is more than given value, the first synchronous rectification is adjusted by PI
Pipe Q3 and the second synchronous rectifier Q4 increases phase shifting angle, accelerates capacitance CoEnergy is to input feedback, to reduce rapidly output electricity
Pressure；
When output voltage declines, then the first synchronous rectifier Q3 and the second synchronous rectifier Q4 is adjusted by PI, reduced
Phase shifting angle reduces capacitive energy to input feedback, to improve output voltage.
LLC resonant converter underloading voltage modulation system input and output voltage relationship be：
Wherein, V2For output voltage amplitude, V1For input voltage amplitude, RoFor output loading, Lr is resonant inductance, and Cr is
Resonant capacitance, ω are angular frequency,For phase shifting angle, output voltage is by input voltage, resonant inductance and capacitance, load and secondary side
The influence of phase shifting angle.
In the strategy by adjust LLC resonant converter be lightly loaded voltage modulation system high frequency transformer secondary side synchronize it is whole
The angle of flow of flow tube makes it be ahead of primary side power tube, and output power is made to be transmitted to mains side from load-side, defeated to adjust
Go out voltage；LLC resonant converter is lightly loaded 6 stages of voltage modulation system circuit mode point：
The S1 stages：Moment is t0-t1；
When the t0 moment, the second power tube Q2 shutdowns, the output capacitance at the second both ends power tube Q2 is charged by resonance current,
The output capacitance at the first both ends power tube Q1 is discharged, and bridge arm mid-point voltage is caused constantly to increase；Due to resonance and excitation electricity
The amplitude of inducing current is unequal, therefore high frequency transformer Tr secondary sides flow through electric current；Due to the pulse of the first synchronous rectifier Q3
Signal arrives before this stage, therefore the first power tube Q1 flows through electric current, before this body diode of the second power tube Q2
Conducting, since electric current is not reduced to 0, continues to be connected；The first synchronous rectifier Q3 and the second synchronous rectifier Q4 are same at this time
When be connected, therefore high frequency transformer both end voltage be 0；This stage output capacitance CoIt discharges to mains side；
The S2 stages：Moment is t1-t2；
When the t1 moment, the output capacitance completion charge and discharge at the first power tube Q1 and the second both ends power tube Q2, therefore the
The electric current that the body diode of one power tube Q1 passes through resonant network；The state of resonant network resistance and current-doubling rectifier and S1 ranks
Duan Xiangtong；First synchronous rectifier Q3 by electric current continuously increase, the body diode of the second synchronous rectifier Q4 is logical
The electric current crossed constantly reduces；
The S3 stages：Moment is t2-t3；
When the t2 moment, the electric current for flowing through the body diode of the second synchronous rectifier Q4 is reduced to 0, and outlet side only has first
Synchronous rectifier Q3 conductings, output capacitance CoIt discharges feedback energy to mains side, semi-bridge alternation circuit and resonant network resistance
State is identical as the S2 stages；High frequency transformer Tr both end voltages are maintained at positive output voltage, therefore excitation and resonant inductance electricity
The amplitude of stream is gradually decreased as 0 by negative value；
The S4 stages：Moment is t3-t4；
When the t3 moment, resonance and excitation inductance current is equal and amplitude is 0, hereafter its value increases to positive value, and encourages
Magnetoelectricity sense amplitude is more than resonant inductance；The body diode of first power tube Q1 turns off, and primary current flows through the first power tube Q1 sheets
Body；Secondary side current flows out transformer Same Name of Ends by the body diode of the first synchronous rectifier Q3 to output capacitance CoCharging,
Output voltage is caused to increase；
The S5 stages：Moment is t4-t5；
When the t4 moment, the first synchronous rectifier Q3 shutdowns cause synchronous rectification state to disappear, but do not influence semi-bridge alternation
The operating status of circuit and resonant network resistance；
The S6 stages：Moment is t5-t6；
When the t5 moment, the pulse signal arrival of the second synchronous rectifier Q4 turns it on, then some electric current flows through,
But numerical value is less than the electric current for the body diode for flowing through the first synchronous rectifier Q3, therefore another part current direction loads；Until
First synchronous rectifier Q3 and the second synchronous rectifier Q4 changes of current are completed, and half of switch periods terminates, into NextState.
In another specific embodiment of the present invention：
LLC resonant converter is mainly made of translation circuit, resonant tank and rectification circuit three parts.Wherein translation circuit
Part can be divided into full-bridge type inverter structure and semibridge system inverter structure by different structure division, and rectification circuit can be divided by different structure
For full-bridge rectification topology, times stream rectification topology and voltage multiplying rectifier topology, by whether controllable standard can to divide into diode whole
Current circuit and circuit of synchronous rectification this two class based on power tube.The present invention is unfolded with semibridge system synchronous rectification LLC converters
Research, circuit topology are as shown in Figure 1.Resonant inductance Lr, resonant capacitance Cr and magnetizing inductance Lm three parts constitute resonance and return
Road, half-bridge converter open the light pipe Q1, Q2, synchronous rectification switch pipe Q3, Q4.
1, synchronous rectification is lightly loaded phase-shift control mode
Modulation waveform is as shown in Figure 2 at light load for LLC converters.Switching tube Q1, Q2 work is 180 degree complementation square wave, is passed through
It is modulated to resonant tank and square-wave voltage is provided, so that input energy is transmitted to output at high-frequency ac sine wave by resonance.It is synchronous
Rectifier switch pipe Q3, Q4 also work as 180 degree complementation square-wave waveform (D=0.5), and access is provided for output capacitance energy feedback.
Two bridge arms are operated in phase shift operation mode, and angle is defined as phase shifting angle between Q1 and Q3.By the conducting for adjusting two bridge arms
Angle, transformation system operation mode adjust input-output power, to stabilize the output voltage.
2, it is lightly loaded voltage modulated mathematical relationship
From the angle analysis of mean power, as long as the angle of flow of secondary side power tube is not ahead of leading for primary side power tube
Current flow angle, it is to be transmitted to load-side from mains side to lead to power always.Therefore, it can be kept advanced by adjusting the angle of flow of secondary side
In primary side, so that output power is transmitted to mains side from load-side and adjust output voltage.
Theoretical point is carried out to the output voltage gain under different first and second sidesway phase angles using First Harmonic Approximation circuit model
Analysis, input and output voltage can be equivalent at sinusoidal voltage source, is analyzed using phase method, analysis circuit is as shown in Figure 3.
If input voltage phasor isOutput voltage phasor isIfIn advanceOne angleIt can be able to according to fig. 3
Lower formula：
In order to finally obtain the mathematical relationship of output voltage gain and secondary side phase shifting angle, formula is simplified below.
For formula (2), first to expression formulaSimplified, as follows：
Enable expression formulaAmplitude be A, phase angle isThen there is following expression：
Then formula (2) can be expressed as：
Similarly, abbreviation is carried out to formula (3), enabledAmplitude be B, then：
Then formula (3) can be expressed as：
Formula (2) and (3), which are then substituted into formula (4), to obtain：
It enablesAmplitude be C, then can be expressed as：
Formula (16) can be established according to bearing power relationship and (17) are as follows：
It can be obtained by formula (16) and (17)：
Had according to trigonometric function relationship：
It can be obtained by formula (19) and (20)：
Then output voltage can be expressed as：
Formula (8) is substituted into formula (22) to obtain：
Output voltage is by input voltage, resonant inductance and capacitance, load and secondary side phase shifting angle known to formula (23)
It influences.According to the positive direction of hypothesis, when secondary side phase shifting angle is ahead of primary side, lateral input side transimission power is exported.
3, it is lightly loaded voltage modulated operational modal analysis
Next the circuit operations conditions in detailed 1/2 switch periods of analysis LLC converters.In 1/2 switch periods
It is interior, 6 operating statuses can be divided into：S1, S2, S3, S4, S5 and S6.
Circuit diagram under S1-S6 operating statuses is as shown in Figure 4.
S1 (t0-t1 stages)：When the t0 moment, power tube Q2 shutdowns, the output capacitance at the both ends power tube Q2 is by resonance electricity
The output capacitance of current charge, the both ends power tube Q1 is discharged, and bridge arm mid-point voltage is caused constantly to increase.Due to resonance and excitation
The amplitude of inductive current is unequal, therefore Circuit Fault on Secondary Transformer flows through electric current.Due to synchronous rectifier Q3 pulse signal herein
It arrives before, therefore Q1 flows through electric current, the body diode conducting of Q2, since electric current is not reduced to 0, continues to lead before this
It is logical.Since Q3 and Q4 are simultaneously turned on, transformer both end voltage is 0.This stage output capacitance is discharged to mains side.
S2 (t1-t2 stages)：When the t1 moment, the output capacitance at the both ends power tube Q1 and Q2 completes charge and discharge, therefore Q1
The body diode electric current that passes through resonant network.Other circuit states are identical as mode S1.Q3 by electric current continuously
Increase, Q4 body diodes by electric current constantly reduce.
S3 (t2-t3 stages)：T2 moment, the electric current for flowing through the body diode of Q4 are reduced to 0, and outlet side only has Q3 conductings,
For output capacitance to mains side electric discharge feedback energy, other circuit states are identical as S2.Transformer both end voltage is maintained at positive defeated
Go out voltage, therefore excitation and the amplitude of resonance inductive current are gradually decreased as 0 by negative value.
S4 (t3-t4 stages)：When the t3 moment, resonance and excitation inductance current is equal and amplitude is 0, hereafter its value to
Positive value increases, and the latter's amplitude is more than the former.The body diode of Q1 turns off, and primary current flows through Q1 itself.Secondary side current stream
Go out transformer Same Name of Ends to charge to output capacitance by the body diode of Q3, output voltage is caused to increase.
S5 (t4-t5 stages)：T4 moment, synchronous rectifier Q3 shutdowns cause synchronous rectification state to disappear, but do not influence it
His circuit operations conditions.
S6 (t5-t6 stages)：The pulse signal arrival at t5 moment, synchronous rectifier Q4 turns it on, then some electricity
Stream flows through, but numerical value is less than the electric current for flowing through Q3 body diodes, therefore some current direction loads.Until Q3, Q4 are changed
Stream is completed, and half of switch periods terminates, into NextState.
According to symmetry, after LLC converters the circuit operation of 1/2 switch periods similar can obtain, analysis method with it is upper
Noodles are seemingly.
4, it is lightly loaded voltage modulated strategy
LLC resonant converter is operated in two kinds of operating modes：Normal operation mode and energy feedback mode.Normal work
When, output voltage is adjusted by controlling switching frequency, system provides energy to output loading；When LLC is operated at light load, system
Into energy feedback pattern, output capacitance releases energy to input side, to reduce output voltage amplitude.
As shown in figure 5, when system is operated in nominal load, output voltage passes through PI regulating switch pipe Q1-Q2 working frequencies
F makes output reach given value Vr；When load lightens, system is operated in maximum switching frequency fmax, by several switch periods,
Output voltage rises, and rises to certain valve system and enters energy feedback pattern, (the Vo when output voltage is more than given value>Vr),
Pi regulator regulating switch pipe Q3-Q4 increases phase shifting angle, accelerates capacitive energy to input feedback, to reduce rapidly output electricity
Pressure；When output voltage declines, then by pi regulator regulating switch pipe Q3-Q4, reduce phase shifting angle, reduces capacitive energy to defeated
Enter feedback, to improve output voltage.Since the work period of two kinds of operation modes is identical, output voltage ripple frequency is identical,
To be conducive to system EMI design.
To sum up, adjusting the secondary side angle of flow makes its angle of flow with primary side power tube in advance, and output capacitance may be implemented
Energy feedback to power supply, output capacitance side is as dead terminal, due to continuing, to mains side feedback energy, to cause output voltage several
It is down to zero, can preferably reduce output voltage.
The present invention utilizes the structure of Circuit Fault on Secondary Transformer synchronous rectifier, by the phase shift for adjusting first and second side power tube
Angle makes output capacitance to mains side feedback energy, to achieve the purpose that reduce underloading output voltage and stablize in rated voltage, this
Efficiency reduces, application range is limited, output voltage ripple is big etc. is not present without increasing hardware cost in the control plan that text proposes
Problem has larger foreground in commercial Application.
It should be understood that for those of ordinary skills, it can be modified or changed according to the above description,
And all these modifications and variations should all belong to the protection domain of appended claims of the present invention.
Claims (6)
1. a kind of LLC resonant converter of energy feedback is lightly loaded voltage modulation system, which is characterized in that including power supply, half bridging
Change circuit, resonant network resistance, high frequency transformer, current-doubling rectifier and output loading；Wherein：
Semi-bridge alternation circuit includes the first power tube (Q1) being connected in series with and the second power tube (Q2)；The of semi-bridge alternation circuit
The drain of one power tube (Q1) is connected with positive pole, and the source level of the second power tube (Q2) is connected with power cathode；Resonant network
Circuit includes resonant capacitance (Cr), resonant inductance (Lr) and high frequency transformer (Tr), resonant capacitance one end (Cr) and semi-bridge alternation
The midpoint of circuit is connected, and the other end is connected after being connected in series with resonant inductance (Lr) with high frequency transformer (Tr) first side winding,
The other end of high frequency transformer (Tr) first side winding is connected with power cathode；Be provided in current-doubling rectifier first synchronize it is whole
Flow tube (Q3) and the second synchronous rectifier (Q4)；The secondary side of high frequency transformer (Tr) uses band centre cap structure, center
Tap is connected with the cathode at output loading end, secondary side both ends respectively with the first synchronous rectifier (Q3) and the second synchronous rectifier
(Q4) source level is connected；The drain electrode of first synchronous rectifier (Q3) and the second synchronous rectifier (Q4) be connected in parallel and with output electricity
Hold (Co) be connected with the anode of output loading.
2. the LLC resonant converter of energy feedback according to claim 1 is lightly loaded voltage modulation system, which is characterized in that
High frequency transformer magnetizing inductance (Lm), resonant inductance (Lr), resonant capacitance (Cr) and high frequency are additionally provided in resonant network resistance
Static exciter inductance (Lm) is sequentially connected.
3. a kind of LLC resonant converter using energy feedback described in claim 1 is lightly loaded voltage modulated strategy, feature exists
In, including following working condition：
When LLC resonant converter underloading voltage modulation system normal work, detection output voltage is compared with given voltage, knot
Fruit is sent into controller and generates control instruction, then generates switching frequency regulating command through voltage-frequency conversion links, controls converter first
Power tube (Q1) and the second power tube (Q2) switching frequency, to adjust output voltage to given voltage, system is to output loading
Energy is provided；
When LLC resonant converter underloading voltage modulation system is operated at light load, system enters energy feedback pattern, adjusts first
Phase shift between power tube (Q1) and the second power tube (Q2) and the first synchronous rectifier (Q3) and the second synchronous rectifier (Q4)
Angle, control output capacitance (Co) release energy to input side, to reduce output voltage amplitude.
4. the LLC resonant converter of energy feedback is lightly loaded voltage modulated strategy according to claim 3, which is characterized in that should
Strategy further includes following working condition：
When load lightens, system is operated in maximum switching frequency, and by several switch periods, output voltage rises, rises to
Certain valve system enters energy feedback pattern, and when output voltage is more than given value, the first synchronous rectifier is adjusted by PI
(Q3) and the second synchronous rectifier (Q4), increase phase shifting angle accelerate capacitance (Co) energy to input feedback, it is defeated to reduce rapidly
Go out voltage；
When output voltage declines, then the first synchronous rectifier (Q3) and the second synchronous rectifier (Q4) are adjusted by PI, reduced
Phase shifting angle reduces capacitive energy to input feedback, to improve output voltage.
5. the LLC resonant converter of energy feedback according to claim 3 is lightly loaded voltage modulated strategy, which is characterized in that
LLC resonant converter underloading voltage modulation system input and output voltage relationship be：
Wherein, V2For output voltage amplitude, V1For input voltage amplitude, RoFor output loading, Lr is resonant inductance, and Cr is resonance
Capacitance, ω are angular frequency,For phase shifting angle, output voltage is by input voltage, resonant inductance and capacitance, load and secondary side phase shift
The influence at angle.
6. the LLC resonant converter of energy feedback according to claim 3 is lightly loaded voltage modulated strategy, which is characterized in that
Leading for the high frequency transformer secondary side synchronous rectifier of voltage modulation system is lightly loaded in the strategy by adjusting LLC resonant converter
Current flow angle makes it be ahead of primary side power tube, and output power is made to be transmitted to mains side from load-side, to adjust output voltage；
LLC resonant converter is lightly loaded 6 stages of voltage modulation system circuit mode point：
The S1 stages：Moment is t0-t1；
When the t0 moment, the second power tube (Q2) shutdown, the output capacitance at the both ends the second power tube (Q2) is charged by resonance current,
The output capacitance at the both ends the first power tube (Q1) is discharged, and bridge arm mid-point voltage is caused constantly to increase；Due to resonance and excitation
The amplitude of inductive current is unequal, therefore high frequency transformer (Tr) secondary side flows through electric current；Due to the first synchronous rectifier (Q3)
Pulse signal arrive before this stage, therefore the first power tube (Q1) flows through electric current, before this second power tube (Q2)
Body diode conducting, since electric current is not reduced to 0, continue to be connected；First synchronous rectifier (Q3) and second same at this time
Step rectifying tube (Q4) simultaneously turns on, therefore high frequency transformer both end voltage is 0；This stage output capacitance (Co) put to mains side
Electricity；
The S2 stages：Moment is t1-t2；
When the t1 moment, the output capacitance completion charge and discharge at the first power tube (Q1) and the both ends the second power tube (Q2), therefore the
The electric current that the body diode of one power tube (Q1) passes through resonant network；The state and S1 of resonant network resistance and current-doubling rectifier
Stage is identical；First synchronous rectifier (Q3) by electric current continuously increase, the body two of the second synchronous rectifier (Q4)
Pole pipe by electric current constantly reduce；
The S3 stages：Moment is t2-t3；
When the t2 moment, the electric current for flowing through the body diode of the second synchronous rectifier (Q4) is reduced to 0, and outlet side only has first same
It walks rectifying tube (Q3) to be connected, output capacitance (Co) discharge feedback energy to mains side, semi-bridge alternation circuit and resonant network resistance
State it is identical as the S2 stages；High frequency transformer (Tr) both end voltage is maintained at positive output voltage, therefore excitation and resonance electricity
The amplitude of inducing current is gradually decreased as 0 by negative value；
The S4 stages：Moment is t3-t4；
When the t3 moment, resonance and excitation inductance current is equal and amplitude is 0, hereafter its value increases to positive value, and excitation electricity
Feel amplitude and is more than resonant inductance；The body diode of first power tube (Q1) turns off, and primary current flows through the first power tube (Q1) originally
Body；Secondary side current flows out transformer Same Name of Ends by the body diode of the first synchronous rectifier (Q3) to output capacitance (Co) fill
Electricity causes output voltage to increase；
The S5 stages：Moment is t4-t5；
When the t4 moment, the first synchronous rectifier (Q3) shutdown causes synchronous rectification state to disappear, but does not influence semi-bridge alternation electricity
The operating status on road and resonant network resistance；
The S6 stages：Moment is t5-t6；
When the t5 moment, the pulse signal arrival of the second synchronous rectifier (Q4) turns it on, then some electric current flows through, but
Numerical value is less than the electric current for the body diode for flowing through the first synchronous rectifier (Q3), therefore another part current direction loads；Until
First synchronous rectifier (Q3) and the second synchronous rectifier (Q4) change of current are completed, and half of switch periods terminates, into NextState.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810215315.6A CN108494256B (en) | 2018-03-15 | 2018-03-15 | Energy feedback LLC resonant converter light-load voltage modulation system and modulation strategy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810215315.6A CN108494256B (en) | 2018-03-15 | 2018-03-15 | Energy feedback LLC resonant converter light-load voltage modulation system and modulation strategy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108494256A true CN108494256A (en) | 2018-09-04 |
| CN108494256B CN108494256B (en) | 2020-02-14 |
Family
ID=63339668
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810215315.6A Expired - Fee Related CN108494256B (en) | 2018-03-15 | 2018-03-15 | Energy feedback LLC resonant converter light-load voltage modulation system and modulation strategy |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108494256B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111277145A (en) * | 2020-03-03 | 2020-06-12 | 合肥阳光电动力科技有限公司 | Control device and control method of DC-DC conversion circuit |
| CN111342663A (en) * | 2020-01-16 | 2020-06-26 | 广州金升阳科技有限公司 | Dummy load circuit of switching power supply and control method thereof |
| CN112152462A (en) * | 2020-08-27 | 2020-12-29 | 东南大学 | Light-load control method for energy feedback of Buck-Boost LLC two-stage converter |
| CN112436732A (en) * | 2020-11-13 | 2021-03-02 | 北京航天发射技术研究所 | Full-digital control method and control system for light-load intermittent output of power supply |
| CN113949282A (en) * | 2021-10-21 | 2022-01-18 | 浙江大学 | Three-port vehicle-mounted charger |
| WO2022133823A1 (en) * | 2020-12-23 | 2022-06-30 | 深圳市汇顶科技股份有限公司 | Antenna circuit, communication chip, terminal device, and feedback tuning method |
| CN114844382A (en) * | 2022-06-09 | 2022-08-02 | 东南大学 | LLC resonant converter synchronous rectification method based on resonant inductor voltage |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101093961A (en) * | 2006-06-22 | 2007-12-26 | 台达电子工业股份有限公司 | Resonance converter, and voltage stabilizing method for implementing light loading and idling load |
| CN102548158A (en) * | 2012-03-28 | 2012-07-04 | 无锡安特源科技有限公司 | Light load control structure of power supply using logic link control (LLC) topology |
-
2018
- 2018-03-15 CN CN201810215315.6A patent/CN108494256B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101093961A (en) * | 2006-06-22 | 2007-12-26 | 台达电子工业股份有限公司 | Resonance converter, and voltage stabilizing method for implementing light loading and idling load |
| CN102548158A (en) * | 2012-03-28 | 2012-07-04 | 无锡安特源科技有限公司 | Light load control structure of power supply using logic link control (LLC) topology |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111342663A (en) * | 2020-01-16 | 2020-06-26 | 广州金升阳科技有限公司 | Dummy load circuit of switching power supply and control method thereof |
| CN111342663B (en) * | 2020-01-16 | 2021-03-05 | 广州金升阳科技有限公司 | Dummy load circuit of switching power supply and control method thereof |
| CN111277145A (en) * | 2020-03-03 | 2020-06-12 | 合肥阳光电动力科技有限公司 | Control device and control method of DC-DC conversion circuit |
| CN111277145B (en) * | 2020-03-03 | 2021-10-29 | 合肥阳光电动力科技有限公司 | Control device and control method of DC-DC conversion circuit |
| CN112152462A (en) * | 2020-08-27 | 2020-12-29 | 东南大学 | Light-load control method for energy feedback of Buck-Boost LLC two-stage converter |
| CN112152462B (en) * | 2020-08-27 | 2021-10-15 | 东南大学 | Light-load control method for energy feedback of Buck-Boost LLC two-stage converter |
| CN112436732A (en) * | 2020-11-13 | 2021-03-02 | 北京航天发射技术研究所 | Full-digital control method and control system for light-load intermittent output of power supply |
| WO2022133823A1 (en) * | 2020-12-23 | 2022-06-30 | 深圳市汇顶科技股份有限公司 | Antenna circuit, communication chip, terminal device, and feedback tuning method |
| CN113949282A (en) * | 2021-10-21 | 2022-01-18 | 浙江大学 | Three-port vehicle-mounted charger |
| CN114844382A (en) * | 2022-06-09 | 2022-08-02 | 东南大学 | LLC resonant converter synchronous rectification method based on resonant inductor voltage |
| CN114844382B (en) * | 2022-06-09 | 2024-06-14 | 东南大学 | LLC resonant converter synchronous rectification method based on resonant inductance voltage |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108494256B (en) | 2020-02-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108494256A (en) | A kind of the LLC resonant converter underloading voltage modulation system and modulation strategy of energy feedback | |
| CN103516196B (en) | Switching power unit | |
| CN107276418B (en) | Wide-range soft switching direct current conversion circuit and control method thereof | |
| CN108512421B (en) | A kind of PFWM control method | |
| CN107966626B (en) | Power module test system of power electronic transformer | |
| CN108736727B (en) | Power converter and control method thereof | |
| US20110242854A1 (en) | Switching power unit | |
| CN109921653B (en) | Single-phase power electronic transformer topological structure and control method thereof | |
| CN111478572B (en) | Single-pole AC-DC converter modal smooth switching and power factor correction control method | |
| CN112436728B (en) | High-efficiency control method of bidirectional resonant converter | |
| EP2975753B1 (en) | A three-level converter | |
| CN106130356A (en) | Based on the adjustable wide input LLC resonant converter of transformer voltage ratio and regulation and control method | |
| CN110445387B (en) | Topological structure and control method of formation and grading power supply | |
| CN110611444B (en) | Bridgeless integrated AC-DC (alternating current-direct current) rectifying circuit and rectifying method | |
| CN103956922A (en) | Switch power supply and control method thereof | |
| CN107947587A (en) | A kind of high-efficiency constant-flow Width funtion output circuit | |
| CN101197543A (en) | Controllable green electric power adopting novel regulation and transformation method | |
| CN213846539U (en) | High-frequency intermittent control system of bidirectional series resonant converter | |
| CN114268104A (en) | Novel transformerless three-bridge-arm series active voltage quality regulator and control method | |
| CN101795004A (en) | Alternating current active power factor correction compensation circuit | |
| CN110729906A (en) | Zero-voltage conversion CLL resonant DC-DC converter and control method thereof | |
| Wu et al. | An LLC converter operating in super-wide output voltage range with variable-mode control strategy | |
| CN107070218B (en) | High-power soft switch chopper circuit | |
| CN210724569U (en) | Zero-voltage conversion CLL resonance DC-DC converter | |
| CN108683353A (en) | Substation's energy-saving multifunctional integration charge and discharge device and control method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200214 |