CN116232083A - LLC synchronous rectification control method, device, equipment and storage medium - Google Patents

LLC synchronous rectification control method, device, equipment and storage medium Download PDF

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Publication number
CN116232083A
CN116232083A CN202310173257.6A CN202310173257A CN116232083A CN 116232083 A CN116232083 A CN 116232083A CN 202310173257 A CN202310173257 A CN 202310173257A CN 116232083 A CN116232083 A CN 116232083A
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llc
frequency
working
determining
resonant converter
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朱景埔
陆奕海
宋晓凡
陈宁
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Mornsun Guangzhou Science and Technology Ltd
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Mornsun Guangzhou Science and Technology Ltd
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    • 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
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/083—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the ignition at the zero crossing of the voltage or the current
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • 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
    • H02M3/01—Resonant DC/DC converters
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses an LLC synchronous rectification control method, a device, equipment and a storage medium, wherein the method comprises the steps of obtaining resonance parameters and determining resonance frequency and resonance period; determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter; determining an operating region of the LLC resonant converter according to the resonant frequency and the operating frequency; and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area. According to the invention, the working area is determined through the resonant frequency and the working frequency, so that the conduction time of the secondary synchronous rectifying tube is controlled, and the secondary synchronous rectifying tube is turned off before the primary switching tube when working in the II area, thereby avoiding the situation of secondary current backflow in the II area and effectively improving the efficiency of the LLC resonant converter; moreover, the control method is simple and clear, and can be realized only by implementing the synchronous rectification time sequence according to the method of the invention without adding an additional detection circuit.

Description

LLC synchronous rectification control method, device, equipment and storage medium
Technical Field
The invention belongs to the technical field of switching power supplies, and particularly relates to an LLC synchronous rectification control method, an LLC synchronous rectification control device, LLC synchronous rectification equipment and a storage medium.
Background
With the maturity of the switching power supply technology, market application is also increasingly demanding high-power small-volume and high-power density switching power supplies, and compared with the traditional analog control mode, the high-power switching power supply product is more prone to a digital control mode. The digital control has the advantages of flexible control strategy, convenience for data exchange communication with the external equipment and convenience for subsequent function upgrading maintenance.
As the regulation mode of the LLC for realizing stable output is PFM, when the LLC circuit with synchronous rectification is output and the synchronous rectification switch tube is on-time T on-SR ＝T on-PR ＝T s When/2, i.e. alternately conducted according to the conventional 50% duty cycle, the LLC main power levels of different working areas can show different working states. When digital control is used, then, when the LLC converter is operated at the resonance frequency point (fs=fr) and at region I (fs>fr), the converter works normally, as shown in the simulation result of fig. 7, wherein the primary side switch tube driving signal, the secondary side synchronous rectifier tube driving signal, the current of the synchronous rectifier tube QSB, the resonance current and the exciting current are respectively from top to bottom in the figure; but when the LLC converter is operating in zone II (fs<fr), the phenomenon that the secondary side output capacitor has energy flowing backward to the resonant cavity occurs, as shown in the simulation result of fig. 8, the primary side switch tube driving signal, the secondary side synchronous rectifying tube driving signal, the current of the synchronous rectifying tube QSB, the resonant current and the exciting current are respectively from top to bottom in the figure, so that the gain and the efficiency of the converter are reduced, and the secondary side synchronous rectifying tube acts instantly to have larger current stress. As can be seen from the simulation result of FIG. 8, the switching time sequence of the primary side switching tube and the secondary side switching tube is as follows when the backflow condition occurs: the secondary synchronous rectifying tube and the primary switching tube are simultaneously turned on and off.
Disclosure of Invention
In order to solve the problems, the invention aims to provide an LLC synchronous rectification control method, an LLC synchronous rectification control device, LLC synchronous rectification control equipment and a storage medium, so that the situation of secondary side energy backflow cannot occur when LLC works in a zone II.
The technical scheme for solving the technical problems is as follows:
in a first aspect, an embodiment of the present invention provides an LLC synchronous rectification control method, including the steps of:
obtaining resonance parameters, and determining resonance frequency and resonance period;
determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter;
determining an operating region of the LLC resonant converter according to the resonant frequency and the operating frequency;
and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area.
Further, the resonance parameter includes a resonance inductance value and a resonance capacitance value.
Further, the determining the working frequency in the steady state according to the highest frequency of the MOS tube in the LLC resonant converter specifically includes:
and according to the highest frequency of the MOS tube in the LLC resonant converter, starting scanning from the highest frequency, and determining the working frequency in a steady state.
Further, the determining the working area of the LLC resonant converter according to the resonant frequency and the working frequency includes:
the working frequency is larger than or equal to the resonant frequency, and the working area of the LLC resonant converter is determined to be a ZVS working area I area;
and the working frequency is smaller than the resonant frequency, and the working area of the LLC resonant converter is determined to be a ZVS working area II.
Further, the controlling the conduction time of the secondary synchronous rectifier of the LLC resonant converter according to the operating region includes:
determining the working area as a ZVS working area I area, and controlling the conduction time of a secondary synchronous rectifying tube of the LLC resonant converter to be as follows:
Figure BDA0004099923410000021
determining the working area as ZVS working area II, and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be as follows:
Figure BDA0004099923410000022
wherein T is on-SR Representing the conduction time of the synchronous rectifying tube at the secondary side, T r Representing the resonance period.
In a second aspect, an embodiment of the present invention provides an LLC synchronous rectification control device, including:
the resonance data determining unit is used for obtaining resonance parameters and determining resonance frequency and resonance period;
the working frequency determining unit is used for determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter;
an operating region determining unit configured to determine an operating region of the LLC resonant converter according to the resonant frequency and the operating frequency;
and the conduction time control unit is used for controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area.
Further, the working area determining unit includes:
the first judging unit is used for determining the working area of the LLC resonant converter as a ZVS working area I area, wherein the working frequency is larger than or equal to the resonant frequency;
and the second judging unit is used for determining the working area of the LLC resonant converter as ZVS working area II area when the working frequency is smaller than the resonant frequency.
Further, the on-time control unit includes:
the first control unit is used for determining the working area as a ZVS working area I area and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be:
Figure BDA0004099923410000031
the second control unit is used for determining the working area as a ZVS working area II area and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be:
Figure BDA0004099923410000032
wherein T is on-SR Representing the conduction time of the synchronous rectifying tube at the secondary side, T r Representing the resonance period.
In a third aspect, an embodiment of the present invention provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: the computer program when executed by the processor implements the steps of the LLC synchronous rectification control method as described in the first aspect.
In a fourth aspect, an embodiment of the present invention provides a computer storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the LLC synchronous rectification control method according to the first aspect.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
according to the invention, the working area is determined through the resonant frequency and the working frequency, so that the conduction time of the secondary synchronous rectifying tube is controlled, and the secondary synchronous rectifying tube is turned off before the primary switching tube when working in the II area, thereby avoiding the situation of secondary current backflow in the II area and effectively improving the efficiency of the LLC resonant converter; moreover, the control method is simple and clear, and can be realized only by implementing the synchronous rectification time sequence according to the method of the invention without adding an additional detection circuit.
Drawings
FIG. 1 is a circuit block diagram of the present invention;
FIG. 2 is a division of LLC working area;
FIG. 3 is a flow chart illustrating steps of an LLC synchronous rectification control method according to the present invention;
FIG. 4 is a block diagram of a LLC synchronous rectification control device according to the present invention;
FIG. 5 is a phase diagram of an analytical method according to the present invention;
FIG. 6 is a timing diagram of LLC operating in zone II;
FIG. 7 is a schematic diagram of simulated waveforms for LLC operating at resonance point and region I without employing the strategy of the present invention;
FIG. 8 is a schematic diagram of simulated waveforms for LLC operating in zone II without employing the strategy of the present invention;
FIG. 9 is a schematic diagram of simulated waveforms of LLC operating in zone II when the strategy of the present invention is introduced;
FIG. 10 is a schematic diagram of simulated waveforms for LLC operating in zone II according to an embodiment of the present invention.
The reference numerals are as follows:
cr, resonance capacitance;
lr, resonant inductance;
lm, exciting the inductor;
QPA, LLC upper tube;
qPB, LLC down tube;
primary side driving signal A, LLC upper tube control signal;
primary side driving signal B, LLC down tube control signal;
QSA, QSB, secondary side synchronous rectifier;
secondary side driving signal a, secondary side driving signal B, secondary side synchronous rectifying tube driving signal.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
Referring to fig. 1, the LLC resonant converter applied in the present solution is formed by sequentially connecting an input bus capacitor, an input square wave generating network, a resonant capacitor, a resonant inductor, a transformer, and an output rectifying network, and in addition, the control system includes a digital control system, a primary side driving isolation unit, a primary side switching tube, a secondary side synchronous rectifying tube, a primary side driving signal amplifying unit, and a secondary side driving signal amplifying unit. The digital control system is used as a core part of control and is used for outputting control signals of a primary side switching tube and a secondary side synchronous rectifying tube, the control signals of the primary side switching tube are output and are connected with one end of a primary side driving isolation unit, and the control signals of the secondary side switching tube are output and are connected with one end of a secondary side driving signal amplifying unit; the other end of the primary side driving isolation unit is connected with one end of the primary side driving signal amplifying unit, the other end of the secondary side driving signal amplifying unit outputs a driving signal to the grid electrode of the secondary side synchronous rectifying tube, and the other end of the primary side driving signal amplifying unit outputs a driving signal to the grid electrode of the primary side switching tube.
As shown in fig. 8, which is a schematic diagram of a simulation waveform of the LLC resonant converter operating in the region ii without intervention, it can be seen that the switching timing of the primary and secondary side switching transistors is: the secondary synchronous rectifying tube and the primary switching tube are simultaneously turned on and off, so that the secondary capacitor current backflow phenomenon is caused. This is parsed to solve the problem.
It should be noted that the operating region of the LLC resonant transformation can be divided into ZVS operating region i and ZVS operating region ii, as shown in fig. 2, at a resonant frequency f r As a demarcation point, f r To the right is ZVS region I, f r And the ZVS working area II area is arranged on the left side.
Referring to fig. 3, an embodiment of the present invention provides an LLC synchronous rectification control method, which includes the following steps:
s100, obtaining resonance parameters, and determining resonance frequency and resonance period.
Wherein the resonance parameter includes a resonance inductance value and a resonance capacitance value.
The resonant frequency is calculated by the following steps:
Figure BDA0004099923410000051
L r for resonant inductance value, C r Is the resonance capacitance value. Resonance period T r And resonant frequency f r Inversely proportional.
S200, determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter.
S300, determining the working area of the LLC resonant converter according to the resonant frequency and the working frequency;
s400, controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area.
According to the invention, the working area is determined through the resonant frequency and the working frequency, so that the conduction time of the secondary synchronous rectifying tube is controlled, and the secondary synchronous rectifying tube is turned off before the primary switching tube when working in the II area, thereby avoiding the situation of secondary current backflow in the II area and effectively improving the efficiency of the LLC resonant converter; moreover, the control method is simple and clear, and can be realized only by implementing the synchronous rectification time sequence according to the method of the invention without adding an additional detection circuit.
In an embodiment, the working frequency in the steady state is determined according to the highest frequency of the MOS transistor in the LLC resonant converter, specifically:
and according to the highest frequency of the MOS tube in the LLC resonant converter, starting scanning from the highest frequency, and determining the working frequency in a steady state.
In one embodiment, step 300 includes:
s301, the working frequency is larger than or equal to the resonant frequency, and the working area of the LLC resonant converter is determined to be a ZVS working area I;
s302, determining the working area of the LLC resonant converter as a ZVS working area II area, wherein the working frequency is smaller than the resonant frequency.
In one embodiment, step 400 includes:
s401, determining the working area as a ZVS working area I area, and controlling the conduction time of a secondary synchronous rectifying tube of the LLC resonant converter to be as follows:
Figure BDA0004099923410000061
judging the ZVS working area I of the LLC resonant converter, and controlling the on time of the secondary synchronous rectifying tube of the LLC resonant converter by using the same grid driving signal as the primary synchronous rectifying tubeThe method comprises the following steps:
Figure BDA0004099923410000062
s402, determining the working area as a ZVS working area II area, and controlling the conduction time of a secondary synchronous rectifying tube of the LLC resonant converter to be as follows:
Figure BDA0004099923410000063
wherein, judging the ZVS working area II area of the LLC resonant converter, and calculating the resonant frequency point f r Corresponding resonant period T r To limit the conduction time T of the secondary synchronous tube on-SR The method comprises the following steps:
Figure BDA0004099923410000071
therefore, the frequency of the secondary synchronous rectifying tube and the frequency of the primary switching tube are equal to be conducted simultaneously, but the secondary synchronous rectifying tube is turned off before the primary switching tube, so that the situation of secondary current backflow can be avoided.
The specific analysis process of the embodiment of the invention is as follows:
when LLC works at resonance point, the resonant frequency is defined by f s ＝f r It can be seen that
Figure BDA0004099923410000072
When LLC works in zone I, the LLC is divided into two parts by f s >f r It can be seen that->
Figure BDA0004099923410000073
And when LLC works in zone II, the LLC is divided into two zones by f s <f r It can be seen that
Figure BDA0004099923410000074
In practical applications, the dead time t is usually considered d To ensure the primary side switching tube ZVS. Analysis of LLC operation in zone II from the above operation procedure, T on-SR ＞T r After the energy transfer from the primary side to the secondary side is completed, the secondary side switch tube which is turned off is still kept on, so that the voltage at two ends of the exciting inductance Lm is kept in a clamping state, L r 、C r Continuing resonance, so that energy in part of the output capacitor is coupled by the transformer and flows back into the resonant cavity; when the on-time is finished and the primary side and secondary side switching tubes are simultaneously turned off, the secondary side of the transformer is turned off, the LLC working process enters dead time, in the dead time, resonance current flows through the body diode of the complementary switching tube of the rectifying circuit, part of energy is re-injected into the output capacitor, the energy of the resonant cavity is reduced, and the current is reduced, namely, the phenomenon of backflow of the LLC working in the II region and the harm of the phenomenon of backflow of the LLC working in the II region are realized.
As shown in fig. 6, the LLC resonant converter is further analyzed by a planar track method in conjunction with fig. 6 in a time domain process according to the following steps:
operating state one (t) 0 ～t 1 )：
The excitation current changes linearly, and has:
Figure BDA0004099923410000075
wherein-I Lm0 At t 0 Exciting current value at moment, V O Is the output voltage average.
The resonant current varies approximately sinusoidally, with:
Figure BDA0004099923410000081
wherein-V Cr0 At t 0 The voltage of the resonance capacitor at the moment,
Figure BDA0004099923410000082
for the resonant angular frequency +.>
Figure BDA0004099923410000083
Is characteristic impedance->
Figure BDA0004099923410000084
t 1 The moment resonant current is:
Figure BDA0004099923410000085
working state two (t) 1 ～t 2 ) The three elements resonate and the phase diagram obtained in the combined state is shown in figure 5.
In the second state, the resonant current is equal to the exciting current and is slightly increased, t 2 The resonance current value at the moment is i Lr (t 2 ) From the phase diagram, it can be seen that:
i Lr (t 2 )＝I Lm0 ；
Figure BDA0004099923410000086
if it is considered that
Figure BDA0004099923410000087
Then there are:
Figure BDA0004099923410000088
the method can obtain:
Figure BDA0004099923410000089
in practice there are:
Figure BDA00040999234100000810
since the excitation current varies linearly, t 0 ～t 1 Is of the actual duration of (a)
Figure BDA0004099923410000091
I.e. the duration of the energy transfer (the required on-time of the secondary side switching tube) is: />
Figure BDA0004099923410000092
From the above analysis, it can be seen that for synchronous rectification LLC circuits operating in the resonant frequency and region i, the same gate drive signal can be used for the primary and secondary sides, and for LLC circuits operating in region ii, the synchronous overall tube conduction time for the secondary side is:
Figure BDA0004099923410000093
the above is derived from the secondary synchronous rectification on-time analysis, and then, as shown in fig. 3, the resonant parameters of the LLC resonant converter are given for the execution of the digital control system: resonant inductance value L r Resonance capacitance value C r Calculating the resonant frequency f by a digital control system r Resonance period T r The method comprises the steps of carrying out a first treatment on the surface of the When LLC resonant converter starts to work, during the output voltage establishment process, the digital control system starts to work from the highest frequency f of a given MOS tube max Starting to scan the LLC resonant converter operating frequency from high to low, reading the operating frequency f when the output is established to the rated output s And resonant frequency f r Comparing; when f s ＞f r Judging that the converter works in the area I, and enabling synchronous rectification on signals of the secondary side to be identical with corresponding on signals of the switching tube of the primary side; when f s ＜f r And judging that the converter works in the zone II, and giving synchronous rectification on time of the secondary side: t (T) on-SR ＜T r /2。
Fig. 9 and fig. 10 are graphs of simulation results of the embodiment of the present invention, in which the primary side switching tube driving signal, the secondary side synchronous rectifying tube driving signal, the current of the synchronous rectifying tube QSB, the resonant current and the exciting current are respectively selected from the following parameters: l (L) r ＝47.5uH，C r As can be seen from fig. 10, the secondary synchronous rectifier is simultaneously turned on and turned off before the primary switching tube corresponding to the primary switching tube at this time on-SR ＝5.19μs＜5.56μs＝T r /2。
Therefore, the invention can control the on time of the secondary synchronous finishing tube when the LLC resonant converter works in the zone II of the ZVS working zone by adopting the partition control strategy, thereby avoiding the condition that the primary secondary switching tube is simultaneously turned on and turned off to cause backflow in the zone II.
Referring to fig. 4, an embodiment of the present invention provides an LLC synchronous rectification control device, which includes:
the resonance data determining unit is used for obtaining resonance parameters and determining resonance frequency and resonance period;
the working frequency determining unit is used for determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter;
an operating region determining unit configured to determine an operating region of the LLC resonant converter according to the resonant frequency and the operating frequency;
and the conduction time control unit is used for controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area.
In an embodiment, the work area determination unit includes:
the first judging unit is used for determining the working area of the LLC resonant converter as a ZVS working area I area, wherein the working frequency is larger than or equal to the resonant frequency;
and the second judging unit is used for determining the working area of the LLC resonant converter as ZVS working area II area when the working frequency is smaller than the resonant frequency.
In one embodiment, the on-time control unit includes:
the first control unit is used for determining the working area as a ZVS working area I area and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be:
Figure BDA0004099923410000101
the second control unit is used for determining the working area as a ZVS working area II area and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be:
Figure BDA0004099923410000102
wherein T is on-SR Representing the conduction time of the synchronous rectifying tube at the secondary side, T r Representing the resonance period.
It should be noted that, for details not disclosed in the startup control device in the embodiment of the present invention, please refer to details disclosed in the startup control method in the embodiment of the present invention, and details are not described here again.
The embodiment of the invention provides electronic equipment, which comprises: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: the computer program when executed by the processor implements the steps of the LLC synchronous rectification control method as described above.
It should be noted that, for details not disclosed in the electronic device in the embodiment of the present invention, please refer to details disclosed in the startup control method in the embodiment of the present invention, and detailed descriptions thereof are omitted herein.
The embodiment of the invention also provides a computer storage medium, wherein a computer program is stored on the computer storage medium, and the computer program realizes the steps of the LLC synchronous rectification control method when being executed by a processor.
It should be noted that, for details not disclosed in the computer storage medium of the embodiment of the present invention, please refer to details disclosed in the startup control method of the embodiment of the present invention, and detailed descriptions thereof are omitted herein.
The above embodiments are merely examples of the present invention and are not intended to limit the scope of the present invention, so any modifications, equivalents, etc. which do not depart from the principles of the present invention should be included in the scope of the present invention.

Claims (10)

1. An LLC synchronous rectification control method is characterized in that the LLC synchronous rectification control method comprises the following steps:
obtaining resonance parameters, and determining resonance frequency and resonance period;
determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter;
determining an operating region of the LLC resonant converter according to the resonant frequency and the operating frequency;
and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area.
2. The LLC synchronous rectification control method as set forth in claim 1, wherein: the resonance parameter includes a resonance inductance value and a resonance capacitance value.
3. The LLC synchronous rectification control method as set forth in claim 1, wherein: the working frequency in steady state is determined according to the highest frequency of the MOS tube in the LLC resonant converter, and the working frequency is specifically as follows:
and according to the highest frequency of the MOS tube in the LLC resonant converter, starting scanning from the highest frequency, and determining the working frequency in a steady state.
4. The LLC synchronous rectification control method as set forth in claim 1, wherein: the determining the working area of the LLC resonant converter according to the resonant frequency and the working frequency comprises the following steps:
the working frequency is larger than or equal to the resonant frequency, and the working area of the LLC resonant converter is determined to be a ZVS working area I area;
and the working frequency is smaller than the resonant frequency, and the working area of the LLC resonant converter is determined to be a ZVS working area II.
5. The LLC synchronous rectification control method as set forth in claim 1, wherein: and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area, wherein the method comprises the following steps of:
determining the working area as ZVS working area I area, and controlling the secondary side of the LLC resonant converter to be identical to the secondary side of the LLC resonant converterThe conduction time of the step-up tube is as follows:
Figure FDA0004099923400000011
determining the working area as ZVS working area II, and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be as follows:
Figure FDA0004099923400000012
wherein T is on-SR Representing the conduction time of the synchronous rectifying tube at the secondary side, T r Representing the resonance period.
6. An LLC synchronous rectification control device, characterized in that it comprises:
the resonance data determining unit is used for obtaining resonance parameters and determining resonance frequency and resonance period;
the working frequency determining unit is used for determining the working frequency in a steady state according to the highest frequency of the MOS tube in the LLC resonant converter;
an operating region determining unit configured to determine an operating region of the LLC resonant converter according to the resonant frequency and the operating frequency;
and the conduction time control unit is used for controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter according to the working area.
7. The LLC synchronous rectification control device as set forth in claim 6, wherein: the work area determining unit includes:
the first judging unit is used for determining the working area of the LLC resonant converter as a ZVS working area I area, wherein the working frequency is larger than or equal to the resonant frequency;
and the second judging unit is used for determining the working area of the LLC resonant converter as ZVS working area II area when the working frequency is smaller than the resonant frequency.
8. The LLC synchronous rectification control device as set forth in claim 6, wherein: the on-time control unit includes:
the first control unit is used for determining the working area as a ZVS working area I area and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be:
Figure FDA0004099923400000021
the second control unit is used for determining the working area as a ZVS working area II area and controlling the conduction time of the secondary synchronous rectifying tube of the LLC resonant converter to be:
Figure FDA0004099923400000022
wherein T is on-SR Representing the conduction time of the synchronous rectifying tube at the secondary side, T r Representing the resonance period.
9. An electronic device, the electronic device comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: the computer program when executed by the processor implements the steps of the LLC synchronous rectification control method according to any one of claims 1 to 5.
10. A computer storage medium having stored thereon a computer program which when executed by a processor performs the steps of the LLC synchronous rectification control method according to any one of claims 1 to 5.
CN202310173257.6A 2023-02-24 2023-02-24 LLC synchronous rectification control method, device, equipment and storage medium Pending CN116232083A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117997084A (en) * 2024-04-07 2024-05-07 广东高斯宝电气技术有限公司 SR dead zone control method for improving LLC topology efficiency

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117997084A (en) * 2024-04-07 2024-05-07 广东高斯宝电气技术有限公司 SR dead zone control method for improving LLC topology efficiency

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