CN113541502A - Half-bridge three-level resonant converter and control method thereof - Google Patents

Half-bridge three-level resonant converter and control method thereof Download PDF

Info

Publication number
CN113541502A
CN113541502A CN202110841857.6A CN202110841857A CN113541502A CN 113541502 A CN113541502 A CN 113541502A CN 202110841857 A CN202110841857 A CN 202110841857A CN 113541502 A CN113541502 A CN 113541502A
Authority
CN
China
Prior art keywords
switching
group
tubes
switch
tube
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.)
Pending
Application number
CN202110841857.6A
Other languages
Chinese (zh)
Inventor
卢松
马红波
李建
易俊宏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Southwest Jiaotong University
Original Assignee
Southwest Jiaotong University
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Southwest Jiaotong University filed Critical Southwest Jiaotong University
Priority to CN202110841857.6A priority Critical patent/CN113541502A/en
Publication of CN113541502A publication Critical patent/CN113541502A/en
Pending legal-status Critical Current

Links

Images

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
    • H02M3/3353—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 at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
    • 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
    • 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

Abstract

The invention discloses a half-bridge three-level resonant converter and a control method thereof. The resonant converter comprises an asymmetric three-level bridge arm circuit, a resonant network, a high-frequency isolation transformer and a rectifying and filtering circuit which are sequentially connected in series; the asymmetric three-level bridge arm circuit comprises a first group of switching tubes, a second group of switching tubes, a third switching tube and a fourth switching tube which are sequentially connected in series; the first group of switching tubes and the second group of switching tubes are respectively formed by connecting N switching tubes in parallel, and N is more than or equal to 2; the drain electrode of the first group of switching tubes is connected with a power supply, and the source electrode of the fourth switching tube is grounded; the drain electrode of the third switching tube and the source electrode of the fourth switching tube are respectively connected to the input end of the resonant network; the flying capacitor is connected across the source electrodes of the first group of switching tubes and the source electrode of the third switching tube. The resonant network is an LLC resonant circuit or an LCC resonant circuit. The invention can realize that the working frequency of the transformer is 2N times of the switching frequency of the switching tube, thereby greatly reducing the volume of the transformer and being beneficial to improving the power density of the converter.

Description

Half-bridge three-level resonant converter and control method thereof
Technical Field
The invention relates to the technical field of resonant converters, in particular to a half-bridge three-level resonant converter and a control method thereof.
Background
The resonant converter has the advantages of simple topology, good soft switching characteristic, high efficiency and the like, and is widely concerned in academia and industry. The common flying capacitor type half-bridge three-level resonant LLC resonant converter is shown in fig. 1, and is composed of a switching inverter bridge arm circuit, a resonant circuit, a transformer, a rectifier circuit, and the like. The switching inverter bridge arm circuit is composed of four switching tubes Q1、Q2、Q3、Q4The direct current voltage is sequentially connected in series and used for inverting the direct current voltage into a square wave; the resonant circuit helps to realize the soft switching characteristic of the switching tube; the transformer and the rectifying circuit are used for transmitting energy to a load end.
The flying capacitor type half-bridge three-level LLC resonant converter shown in fig. 1 has two control strategies, which are a conventional control strategy and a frequency-doubling modulation control strategy, respectively. Conventional control strategy is shown in fig. 2a, switching tube Q in topology1And Q2Driven by a 50% duty cycle control signal, and switching transistor Q3And Q4Driven by another complementary 50% duty ratio control signal, so that the peak-to-peak value of the resonant cavity input voltage inverted by the three-level bridge arm is equal to the input voltage VIN. The frequency multiplication control strategy is shown in FIG. 2b, and the switching tube Q in the topology1And Q2Driven by control signals with 25% duty ratio, and the drive signals are 180 degrees different from each other, and a switching tube Q3And Q4Driven by a 75% duty cycle control signal and switching tube Q3Driving signal and switching tube Q2The driving signals of the switch tube Q are complementary4Driving signal and switching tube Q1Are complementary to each other. The frequency multiplication modulation control half-bridge three-level LLC has two changes of the traditional control strategy: the peak value of the input voltage of the resonant network is half of that of a traditional 50% duty ratio controlled half-bridge three-level LLC resonant converter, namely half of the input voltage; and secondly, the input voltage frequency of the resonant network is 2 times of the switching frequency of the four switching tubes. In practical application, dead time is required between the driving signals of the two tubes for preventing the tubes from being connected in a straight-through manner and realizing zero-voltage conduction of the switching tubes.
Obviously, the half-bridge three-level LLC resonant converter based on the frequency multiplication modulation strategy has higher voltage reduction characteristic due to the fact that the input voltage of the resonant cavity is reduced by half, is more suitable for working in an application scene with high voltage reduction ratio, and the frequency multiplication characteristic of the half-bridge three-level LLC resonant converter is also beneficial to reducing the size of a transformer and better LLC gain adjustment capacity. For example, a topology proposed by an article entitled a Novel AC/DC Converter Based on Stacked Boost Circuit and Dual-Mode LLC Circuit (IEEE Transactions on industrial Applications,2020.3015793) published by tinting Yao et al, the three-level DC/DC part in the Converter proposed by the article makes use of the difference in characteristics of the three-level LLC under a frequency doubling modulation strategy to realize that the Converter can switch under the traditional modulation and frequency doubling modulation strategies, thereby ensuring a wider input voltage range and meeting the requirement of Converter gain adjustment.
However, with the progress of semiconductor devices, magnetic materials and related process technologies, resonant converters such as LLC have been developed vigorously, and how to improve the power density of the converter as much as possible while ensuring the working efficiency of the converter is a research hotspot in the academic and industrial fields at present. In order to increase the power density of the converter, it is desirable to make the converter as small as possible, in particular the magnetic elements of the converter. Accordingly, it is inevitably necessary to increase the operating frequency of the transducer, particularly the operating frequency of the magnetic element. It is also well known in the art that the higher the operating frequency of a magnetic element, the smaller the volume of the magnetic element. The working range of the common ferrite material magnetic core is about hundreds of kHz to 1MHz, the manganese-zinc power material magnetic core can work to 3MHz or more, even the microwave ferrite material and other hexagonal crystal materials can work to hundreds of GHz. However, in practical applications, the switching frequency of the switching device limits further improvement of the operating frequency of the magnetic core material of the resonant converter such as LLC. In addition, because the LLC resonant converter often adjusts the output voltage by changing the switching frequency, if the input-output range of the converter design is too wide, the switching frequency of the converter may also change too widely, which may result in high requirements for the switching capability of the switching device, and may cause circuit damage in severe cases. Therefore, it is necessary to study how to ensure that the switching frequency of the converter is within an acceptable range of the device capability, and at the same time, to further increase the operating frequency of the magnetic element. Although the traditional half-bridge three-level LLC resonant converter based on the frequency doubling modulation strategy can already realize frequency doubling of the transformer operating frequency to the switching frequency, under specific application scenarios such as wide input/output voltage regulation range, extremely high requirements for the volume of the magnetic element, and the like, the frequency doubling capability is still insufficient for improving the operating frequency of the magnetic element, optimizing the volume of the magnetic element, and regulating the voltage of the resonant converter.
Disclosure of Invention
The invention aims to provide a half-bridge three-level resonant converter and a control method thereof, which solve the problems of insufficient working frequency of a magnetic element, insufficient frequency modulation range of switching frequency of the resonant converter and the like under the specific application scenes that the resonant converter has wide voltage regulation range of certain input and output ranges and extremely high volume requirements of the magnetic element. The invention can realize that the working frequency of the transformer is 2N (N is a positive integer) times of the switching frequency of the switching tube while keeping the high step-down ratio characteristic of the traditional frequency doubling modulation method, thereby greatly reducing the volume of the transformer and being beneficial to improving the power density of the converter; in addition, due to the 2N frequency doubling effect of the converter, the wider resonant cavity input voltage frequency adjustment can be realized within a smaller switching frequency variation range, so that the resonant cavity gain of the converter is adjusted, and the wider input and output voltage adjustment range is realized; and the first group of switching tubes and the second group of switching tubes are in a staggered parallel connection effect, so that the conduction loss of the switching tubes is reduced, and the conversion efficiency of the converter is improved.
The technical scheme for realizing the purpose of the invention is as follows:
a half-bridge three-level resonant converter comprises an asymmetric three-level bridge arm circuit, a resonant network, a high-frequency isolation transformer and a rectifying and filtering circuit which are sequentially connected in series; the asymmetric three-level bridge arm circuit comprises a first group of switching tubes, a second group of switching tubes, a third switching tube and a fourth switching tube which are sequentially connected in series; the first group of switching tubes and the second group of switching tubes are respectively formed by connecting N switching tubes in parallel, and N is more than or equal to 2; the drain electrode of the first group of switching tubes is connected with a power supply, and the source electrode of the fourth switching tube is grounded; the drain electrode of the third switching tube and the source electrode of the fourth switching tube are respectively connected to the input end of the resonant network; the flying capacitor is connected across the source electrodes of the first group of switching tubes and the source electrode of the third switching tube.
In a further technical scheme, the resonant network is an LLC resonant circuit or an LCC resonant circuit.
The control method of the half-bridge three-level resonant converter comprises the following steps:
respectively applying to N switching tubes of the first group of switching tubes and N switching tubes of the second group of switching tubes
Figure BDA0003179176850000021
A drive signal of a duty cycle; the phase of the driving signal of the first switch tube of the second group of switch tubes is lagged behind the phase of the driving signal of the first switch tube of the first group of switch tubes
Figure BDA0003179176850000031
The phase of the driving signal of the second switch tube of the first group of switch tubes is lagged behind the phase of the driving signal of the first switch tube of the second group of switch tubes
Figure BDA0003179176850000032
The phase of the driving signal of the second switch tube of the second group of switch tubes is lagged behind the phase of the driving signal of the second switch tube of the first group of switch tubes
Figure BDA0003179176850000033
The rest is analogized; the driving signal of the third switch tube is a complementary signal of the driving signals of the N switch tubes of the second group of switch tubes after logical OR operation; the driving signal of the fourth switching tube is a complementary signal of the driving signals of the N switching tubes of the first group of switching tubes after logical OR operation.
The other half-bridge three-level resonant converter comprises an asymmetric three-level bridge arm circuit, a resonant network, a high-frequency isolation transformer and a rectifying and filtering circuit which are sequentially connected in series; the asymmetric three-level bridge arm circuit comprises a first switching tube, a second switching tube, a third group of switching tubes and a fourth group of switching tubes which are sequentially connected in series; the third group of switching tubes and the fourth group of switching tubes are respectively formed by connecting N switching tubes in parallel, and N is more than or equal to 2; the drain electrode of the first switch tube is connected with a power supply, and the source electrode of the fourth switch tube is grounded; the drain electrode of the first switching tube and the source electrode of the second switching tube are respectively connected to the input end of the resonant network; the flying capacitor is connected across the source electrode of the first switch tube and the source electrode of the third switch tube.
In a further technical scheme, the resonant network is an LLC resonant circuit or an LCC resonant circuit.
The control method of the half-bridge three-level resonant converter comprises the following steps:
respectively applying to N switching tubes of the third group of switching tubes and N switching tubes of the fourth group of switching tubes
Figure BDA0003179176850000034
A drive signal of a duty cycle; the phase of the driving signal of the first switch tube of the third group of switch tubes is lagged behind the phase of the driving signal of the first switch tube of the fourth group of switch tubes
Figure BDA0003179176850000035
The second switch tube of the fourth group of switch tubes has a phase lag behind the phase of the driving signal of the first switch tube of the third group of switch tubes
Figure BDA0003179176850000036
The phase of the driving signal of the second switch tube of the third group of switch tubes is lagged behind that of the driving signal of the second switch tube of the fourth group of switch tubes
Figure BDA0003179176850000037
The rest is analogized; the driving signal of the first switching tube is a complementary signal of the driving signals of the N switching tubes of the fourth group of switching tubes after logical OR operation; the driving signal of the second switch tube is a complementary signal of the driving signals of the N switch tubes of the third group of switch tubes after logical OR operation.
Compared with the prior art, the invention has the advantages that,
1. the high step-down ratio characteristic of the traditional frequency doubling modulation method is kept, and meanwhile, the working frequency of the transformer can be 2N (N is a positive integer) times of the switching frequency of the switching tube, so that the size of the transformer is greatly reduced, and the power density of the converter is improved.
2. The resonant cavity input voltage frequency can be adjusted in a wider range of change of the switching frequency, so that the resonant cavity gain is adjusted, and the wider input and output voltage adjusting range of the resonant converter is realized.
3. The first group of switch tubes and the second group of switch tubes are in a staggered parallel connection effect, so that the conduction loss of the switch tubes is reduced, and the conversion efficiency of the converter is improved.
Drawings
Fig. 1 is a block diagram of a flying capacitor type half-bridge three-level LLC resonant converter.
Fig. 2a is a schematic diagram of a conventional control strategy of a flying capacitor type half-bridge three-level LLC resonant converter.
Fig. 2b is a schematic diagram of a frequency multiplication modulation strategy of the flying capacitor type half-bridge three-level LLC resonant converter.
Fig. 3a is a block diagram of an asymmetric bridge arm half bridge three-level LLC resonant converter.
Fig. 3b is a block diagram of another asymmetric leg half bridge three level LLC resonant converter.
Fig. 4a is a structural diagram of a frequency-doubled asymmetric bridge arm half-bridge three-level LLC resonant converter in the first embodiment 4.
Fig. 4b is a schematic diagram of a control method of the frequency-doubling asymmetric bridge arm half-bridge three-level LLC resonant converter in the first embodiment 4.
Fig. 4c is a structural diagram of a frequency-doubled asymmetric bridge arm half-bridge three-level LLC resonant converter of the second embodiment 4.
Fig. 4d is a schematic diagram of a control method of a frequency-doubling asymmetric bridge arm half-bridge three-level LLC resonant converter in the second embodiment 4.
Fig. 5a is a structural diagram of a frequency-doubled asymmetric bridge arm half-bridge three-level LLC resonant converter of the third embodiment 6.
Fig. 5b is a schematic diagram of a control method of a frequency-doubling asymmetric bridge arm half-bridge three-level LLC resonant converter in the third embodiment 6.
Fig. 5c is a structural diagram of a frequency-doubled asymmetric bridge arm half-bridge three-level LLC resonant converter of the fourth embodiment 6.
Fig. 6 is a steady-state operation waveform diagram of the frequency-doubled asymmetric bridge arm half-bridge three-level LLC resonant converter in the first embodiment 4.
Fig. 7-1 is an equivalent circuit diagram in the operating state 1 of the first embodiment.
Fig. 7-2 is an equivalent circuit diagram in the operating state 2 and the operating state 10 of the first embodiment.
Fig. 7-3 are equivalent circuit diagrams in four stages of the operating states 3, 7, 11, 15 of the first embodiment.
Fig. 7 to 4 are equivalent circuit diagrams in the operating state 4 and the operating state 12 of the first embodiment.
Fig. 7 to 5 are equivalent circuit diagrams in the operating state 5 of the first embodiment.
Fig. 7 to 6 are equivalent circuit diagrams in the operating state 6 and the operating state 14 of the first embodiment.
Fig. 7 to 7 are equivalent circuit diagrams in the operating state 8 and the operating state 16 of the first embodiment.
Fig. 7 to 8 are equivalent circuit diagrams in the operating state 9 of the first embodiment.
Fig. 7 to 9 are equivalent circuit diagrams in the operating state 13 of the first embodiment.
Fig. 8 is a structural diagram of a 2N frequency multiplication asymmetric bridge arm half-bridge three-level LCC resonant converter in accordance with the fifth embodiment.
Main symbol names in the above figures: vINIs an input supply voltage; q11、Q12、…、Q1NA first group of switch tubes; q21、Q22、…、Q2NA second group of switch tubes; q31、Q32、…、Q3NA third group of switch tubes; q41、Q42、…、Q4NA fourth group of switch tubes; q1、Q2、Q3、Q4Is respectively a first, a second, a third and a fourthClosing the pipe; cQ11、CQ12、…、CQ1N、CQ21、CQ22、…、CQ2N、CQ31、CQ32、…、CQ3N、CQ41、CQ42、…、CQ4N、CQ1、CQ2、CQ3、CQ4Is parasitic capacitance of the switch tube; dQ11、DQ12、…、DQ1N、DQ21、DQ22、…、DQ2N、DQ31、DQ32、…、DQ3N、DQ41、DQ42、…、DQ4N、DQ1、DQ2、DQ3、DQ4Is a switch body diode; cFLYIs a flying capacitor; l isrIs a resonant inductor in a resonant network; l ismIs an excitation inductance in the resonant network; crIs a resonant capacitor in the resonant network; TR is a first isolation transformer; d1、D2Is a secondary side rectifier diode; c0Is an output filter capacitor; rLIs an output load; v0Is the output voltage; vABThe voltage between the point A and the point B is the input voltage of the resonant network; vgs_Q11、Vgs_Q12、Vgs_Q13、Vgs_Q21、Vgs_Q22、Vgs_Q23、Vgs_Q31、Vgs_Q32、Vgs_Q41、Vgs_Q42、Vgs_Q1、Vgs_Q2、Vgs_Q3、Vgs_Q4Is a switching tube driving waveform; i.e. iLrIs a resonant current waveform in the resonant network; i.e. iLmIs the waveform of the exciting current in the resonant network; i.e. iD1、iD2Is a secondary side rectifier diode current waveform; n is the number of turns of the isolation transformer.
Detailed Description
The invention provides a novel half-bridge three-level LLC resonant converter of an asymmetric bridge arm and a frequency multiplication modulation control strategy thereof, which can realize that the input voltage frequency is 4 times, 6 times, … times and 2N times (N is a positive integer and is more than or equal to 2) of the switching frequency of a switching tube while keeping the high step-down ratio characteristic, thereby reducing the volume and the loss of a transformer.
The topology provided by the invention has the main advantages that: the asymmetric half-bridge three-level LLC resonant converter not only reserves the high step-down ratio characteristic of the original frequency multiplication modulation strategy, namely the peak value of the input voltage of the resonant cavity is half of the input voltage, but also can realize that the input voltage frequency is 4 times, 6 times, … times and 2N times of the switching frequency of the switching tube, thereby improving the working frequency of the transformer greatly and being beneficial to reducing the volume and the loss of the transformer; compared with the traditional half-bridge three-level LLC converter which can only realize double frequency modulation, the switching loss of the converter is theoretically consistent, but due to the provided asymmetric three-level topology, the number of the switching tubes is increased, which is equivalent to increasing a shunt branch, so that the conduction loss of the switching tubes is favorably reduced, and the conversion efficiency of the converter is improved. In line with conventional LLC converters, the converter regulates the output voltage by varying the frequency of the switching tube control signal. Therefore, due to the frequency doubling effect of the converter, the converter can realize a wider input-output voltage regulation range with a smaller switching frequency variation range.
The asymmetric bridge arm half-bridge three-level LLC resonant converter based on the frequency multiplication modulation strategy is shown in fig. 3a and fig. 3 b. The topology of fig. 3a is controlled in the following manner: for the first group of switching tubes (Q)11～Q1N) A second group of switch tubes (Q)21～Q2N) Application of
Figure BDA0003179176850000051
(N is a positive integer, and N is more than or equal to 2) duty ratio, and the phases of the driving signals of the switching tubes in the same group are sequentially mutually different
Figure BDA0003179176850000052
And a second group of switching tubes (Q)21～Q2N) Comparing the switching tubes (Q) in the first group in turn11～Q1N) Hysteresis
Figure BDA0003179176850000053
And a third switching tube (Q)3) The driving signal of (1) is all the second group of switching tubes (Q)21～Q2N) The complementary signal after the logical OR operation is firstly solved by the driving signal, and the fourth switch tube (Q)4) The driving signal of (A) is all the first group of switching tubes (Q)11～Q1N) The driving signals are complementary signals after logical OR operation. The topology of fig. 3b is controlled in the following manner: for the third group of switching tubes (Q)31～Q3N) And a fourth group of switching tubes (Q)41～Q4N) Application of
Figure BDA0003179176850000054
(N is a positive integer, and N is more than or equal to 2) duty ratio, and the phases of the driving signals of the switching tubes in the same group are sequentially mutually different
Figure BDA0003179176850000055
And a third group of switching tubes (Q)31～Q3N) Comparing the switching tubes (Q) in the fourth group in turn41～Q4N) Hysteresis
Figure BDA0003179176850000056
And a first switch tube (Q)1) The driving signal of (C) is all the fourth group of switching tubes (Q)41～Q4N) A complementary signal after logical OR operation is firstly found by the driving signal, a second switch tube (Q)2) The driving signal of (C) is all the third group of switching tubes (Q)31～Q3N) The driving signals are complementary signals after logical OR operation.
Based on the idea of frequency multiplication control, it is easy to summarize the asymmetrical three-level topology and frequency multiplication control strategy thereof during frequency multiplication of 6 to 2N. Taking the topology of fig. 3a as an example, it is shown in table 1.
TABLE 1
Figure BDA0003179176850000061
The topology and control scheme of a 4-frequency-doubled asymmetric half-bridge three-level LLC resonant converter with this control concept are shown in fig. 4a and fig. 4b, respectively. The control strategy for realizing the frequency control of the 4 times of the input voltage of the resonant cavity is as follows: for the first group of switching tubes (Q)11、Q12) A second group of switch tubes (Q)21、Q22) A 12.5% duty cycle drive signal is applied,the phase difference of the switch tubes in the same group is 180 degrees, and the second group of switch tubes (Q)21、Q22) Lagging the first set of switching tubes (Q) in sequence11、Q12) Phase 90 DEG, to the third switching tube (Q)3) And a fourth switching tube (Q)4) All apply a drive signal with a 75% duty cycle, and the third switch tube (Q)3) The driving signal of (A) is a second group of switching tubes (Q)21) And a switch tube (Q)22) The drive signal of (2) first obtains a complementary signal after logical OR operation, and a fourth switching tube (Q)4) The driving signal of (A) is a first group of switching tubes (Q)11) And a switch tube (Q)12) The driving signal of (2) first obtains a complementary signal after logical OR operation, and at the moment, the switching tube Q3And Q4The switching frequency of (2) is 2 times of the switching frequency of the asymmetric switching tube.
Similarly, the control scheme of the 4-frequency-doubled asymmetric half-bridge three-level LLC resonant converter topology shown in fig. 4c is shown in fig. 4 d. The method specifically comprises the following steps: for the third group of switching tubes (Q)31、Q32) And a fourth group of switching tubes (Q)41、Q42) All apply drive signals with 12.5% duty ratio, the phase difference of the switching tubes in the same group is 180 degrees, and the switching tubes in the third group (Q)31、Q32) Lagging the fourth group of switching tubes (Q) in sequence41、Q42) Phase 90 DEG, to the first switch tube (Q)1) And a fourth switching tube (Q)2) All apply a drive signal with a 75% duty cycle, and a first switching tube (Q)1) The driving signal of (2) is a fourth group of switching tubes (Q)41) And a switch tube (Q)42) The drive signal of (2) first obtains a complementary signal after logical OR operation, and a fourth switching tube (Q)2) The driving signal of (2) is a third group of switching tubes (Q)31) And a switch tube (Q)32) The driving signal of (2) first obtains a complementary signal after logical OR operation, and at the moment, the switching tube Q1And Q2The switching frequency of (2) is 2 times of the switching frequency of the asymmetric switching tube.
Similarly, the topology and the control mode of the 6-frequency-doubling asymmetric half-bridge three-level LLC resonant converter based on the control idea are shown in fig. 5a and fig. 5b, respectively. To achieve the input voltage frequency 6 times of the switching frequency of the switching tube, the control strategy becomes: for the first group of switch tubes(Q11、Q12、Q13) A second group of switch tubes (Q)21、Q22、Q23) 1/12 duty cycle driving signals are applied, the switching tubes in the same group are 120 degrees out of phase, and the switching tubes in the second group (Q)21、Q22、Q23) Lagging the first set of switching tubes (Q) in sequence11、Q12、Q13) Phase position is 60 degrees, and the switching tube Q is aligned3And Q4A 75% duty cycle drive signal is still applied and the transistor Q is switched3The driving signal of (A) is a second group of switching tubes (Q)21、Q22、Q23) The driving signal of (2) firstly obtains a complementary signal after logical OR operation, and a switching tube Q4The driving signal of (A) is a first group of switching tubes (Q)11、Q12、Q13) The drive signal firstly obtains a complementary signal after logical OR operation, and the corresponding switch tube Q at the time3And Q4The switching frequency of (2) is 3 times of the switching frequency of the asymmetric switching tube.
Similarly, a control method of the 6 frequency-doubled asymmetric half-bridge three-level LLC resonant converter topology shown in fig. 5c can be derived accordingly, and will not be described here again. In addition, the half-bridge three-level topology of the asymmetric bridge arm and the control strategy thereof provided by the invention can also be used with a resonant converter such as an LCC (lower control circuit) and the like, as shown in FIG. 8.
The half-bridge three-level LLC resonant converter with any even-number frequency multiplication asymmetric bridge arm has similarity, so that the specific working mode of the half-bridge three-level LLC resonant converter with the 4-number frequency multiplication asymmetric bridge arm is introduced by taking the half-bridge three-level LLC resonant converter as an example for analysis.
The topologies shown in fig. 3a and fig. 3b are 2N frequency-doubled asymmetric half-bridge three-level LLC resonant converters proposed in the present invention. The specific circuit comprises the following steps: flying capacitor CFLY(1) The high-frequency three-level bridge circuit comprises an asymmetric three-level bridge arm (2), a resonant network (3), a high-frequency isolation transformer (4) and a rectifying and filtering circuit (5). The secondary side of the isolation transformer can adopt full-wave rectification, full-bridge rectification or other modes, wherein full-wave rectification is taken as an example, D1、D2Two rectifier diodes. The resonant network is used for realizing zero-voltage switching of the switching tube and zero-current switching of the rectifier diode.
The specific operation of the first embodiment will now be described with reference to the structure shown in fig. 4a and the control strategy shown in fig. 4 b. Before performing a detailed modal analysis, the following assumptions are made:
1. the output filter capacitor is large enough to make the output voltage as a constant value in one switching period;
2. flying capacitor CFLYThe resonance capacitance is large enough not to affect the resonance frequency of the resonance network.
So that f can be usedrRepresenting the resonant capacitance CrAnd a resonant inductor LrResonant frequency of both, by fmRepresenting the resonant capacitance CrResonant inductor LrAnd an excitation inductance LmResonant frequency of the three, andr>fm. Due to the magnitude relationship between the switching frequency fs and the resonant frequency fr, the operating mode of the converter is divided into three modes, namely, the under-resonant mode (fs)<fr), quasi-resonant mode (fs ═ fr), and over-resonant mode (fs)>fr). The operation principle of the converter in different modes is slightly different, but the LLC converter has the highest efficiency when operating in a quasi-resonant mode (fs ═ fr). Therefore, the present description only deals with the case of fs ═ fr to analyze the working principle, and the other two analysis methods are similar. In the quasi-resonant mode (fs ═ fr) mode, one switching period of the converter can be divided into 16 working modes, and in the steady-state operation, the waveforms of each key voltage and current are as shown in fig. 6.
The specific working principle is as follows:
(1) operating state 1, as shown in fig. 7-1: t is t0<t<t1And (5) stage. At t0Time, Q11Zero voltage conduction, and Q3Is still in a conducting state, so that the resonant cavity input voltage VABAt Q11After complete conduction, it is 0.5VIN. L in resonant networkrAnd CrSeries resonance, forward resonance of resonant current in resonant cavity, secondary side diode D2Conducting so that the exciting current is changed from the minimum value to nV0/LmThe slope of (a) increases linearly, and the difference between the resonant current and the excitation current in the resonant cavity transfers energy.
(2) In the working state 2, the operation of the device is carried out,as shown in fig. 7-2: t is t1<t<t2And (5) stage. At t1Time, Q11Turn off, the input voltage of resonant cavity is from 0.5VINStarting commutation, diode D2The middle resonance current just resonates to 0, and the primary side resonance current in the resonant cavity is equal to the maximum value of the excitation current. The load energy is provided by an output capacitor. Note that in this stage is L in the cavityr、Lm、CrThe three elements resonate together. Since the resonant periods of the three elements are long, it can be approximated that the resonant current in the dead time remains approximately constant. Due to Q11And Q12Parallel connection, so that the resonant current in the resonant cavity will simultaneously supply Q in this stage11And Q12Output capacitor CQ11、CQ12Charging and Q4Output capacitor CQ4And (4) discharging. Is in the next state Q4The zero voltage conduction creates conditions.
(3) Operating state 3, as shown in fig. 7-3: t is t2<t<t3And (5) stage. At t2Time, Q4Zero voltage conduction, and Q3Is still in a conducting state, so that the resonant cavity input voltage VABAt Q4After complete conduction is 0, LrAnd CrAnd (4) series resonance. From the direction of the same name end, the secondary side diode D in the stage1When the resonant cavity is conducted, the resonant current in the resonant cavity can be reversely resonated to zero firstly, and the excitation current is set to-nV from the maximum value0/LmThe slope of (a) decreases linearly. The difference between the resonant current and the excitation current in the resonant cavity transfers energy.
(4) Operating state 4, as shown in fig. 7-4: t is t3<t<t4And (5) stage. At t3Time, Q3Turn-off, the resonant cavity input voltage is reversed from 0, and the diode D1The middle resonance current just resonates to 0, and the primary side resonance current in the resonant cavity is equal to the maximum value of the excitation current. Similar to mode 2, in this phase, the load energy is provided by the output capacitor. The resonant current in the resonant cavity will equal the excitation current and give Q21And Q22Output capacitor CQ21、CQ22Discharge, give Q3Output capacitor CQ3And (6) charging. Is the next oneState Q21The zero voltage conduction creates conditions.
(5) Operating state 5, as shown in fig. 7-5: t is t4<t<t5And (5) stage. At t4Time, Q21Zero voltage conduction, and Q4Is still in a conducting state, so that the resonant cavity input voltage VABAt Q4After complete conduction, it is 0.5VIN，LrAnd CrThe current in the resonant cavity is positively resonated, energy is transferred to a load through a high-frequency transformer, and the exciting current is linearly increased from a minimum value. Secondary side diode D2And conducting.
(6) Operating state 6, as shown in fig. 7-6: t is t5<t<t6And (5) stage. At t5Time, Q21Is turned off, and Q4The resonant cavity is still in a conducting state, and the input voltage of the resonant cavity is controlled to be 0.5VINStarting commutation, diode D2The middle resonance current just resonates to 0, and the primary side resonance current in the resonant cavity is equal to the maximum value of the excitation current. Similar to modes 2 and 4, in this phase, the load energy is provided by the output capacitor. The resonant current in the resonant cavity will equal the excitation current and give Q21And Q22Output capacitor CQ21、CQ22Charging, giving Q3Output capacitor CQ3And (4) discharging. Is in the next state Q3The zero voltage conduction creates conditions.
(7) Operating state 7, as shown in fig. 7-3: t is t6<t<t7And (5) stage. At t6Time, Q3Zero voltage conduction, and Q4Still in the conducting state, so the circuit working state is consistent with the working state 3.
(8) Operating state 8, as shown in fig. 7-7: t is t7<t<t8And (5) stage. At t7Time, Q4Is turned off, and Q3Is still in a conducting state, so that the resonant cavity input voltage is reversed from 0, and the diode D1The middle resonance current just resonates to 0, and similarly, in the stage, the load energy is provided by the output capacitor, and the exciting current in the resonant cavity gives Q4Output capacitor CQ4Charging, giving Q11And Q12Output capacitor CQ11、CQ12And (4) discharging. Is in the next state Q12The zero voltage conduction creates conditions.
(9) Operating state 9, as shown in fig. 7-8: t is t8<t<t9And (5) stage. At t8Time, Q12Zero voltage conduction, and Q3On state, so that the resonant cavity input voltage VABIs 0.5VINThe resonant cavity current positive resonance transfers energy to the load, and the exciting current increases linearly. Secondary side diode D2And conducting.
(10) Operating condition 10, as shown in fig. 7-2: : t is t9<t<t10Stage at t9Time, Q11And (4) turning off, wherein the working state of the circuit is consistent with the working state 2.
(11) Operating state 11, as shown in fig. 7-3: : t is t10<t<t11Stage at t10Time, Q4Zero voltage conduction, this phase is consistent with operating state 3.
(12) Operating state 12, as shown in fig. 7-4: : t is t11<t<t12Stage at t11Time, Q3Off, this phase corresponding to operating state 4.
(13) Operating state 13, as shown in fig. 7-9: : t is t12<t<t13Stage at t12Time, Q22Zero voltage conduction, and Q4Is in a conducting state, so that the resonant cavity input voltage VABIs 0.5VINThe resonant cavity current positive resonance transfers energy to the load, the exciting current increases linearly, and the secondary side diode D2And conducting.
(14) Operating state 14, as shown in fig. 7-6: t is t13<t<t14Stage at t13Time, Q22Off, so this phase coincides with operating state 6.
(15) Operating state 15, as shown in fig. 7-3: t is t14<t<t15Stage at t14Time, Q3Zero voltage conduction, this phase is consistent with operating state 3.
(16) Operating state 16, as shown in fig. 7-8: t is t15To t1Stage at t15Time, Q4Off, this phase corresponding to the operating state 8.
In conclusion, the novel half-bridge three-level LLC resonant converter of the asymmetric bridge arm and the frequency multiplication modulation control strategy thereof reserve the high step-down ratio characteristic of the traditional frequency multiplication modulation method, and can realize that the working frequency of the transformer is 2N (N is a positive integer) times of the switching frequency of the switching tube, thereby greatly reducing the volume of the transformer and being beneficial to improving the power density of the converter; meanwhile, wider resonant cavity input voltage frequency adjustment can be realized within a smaller switching frequency variation range, so that resonant cavity gain is adjusted, and wider input and output voltage adjustment range of the resonant converter is realized; in addition, the asymmetric three-level bridge arm switching tubes are in a staggered parallel connection effect, so that the conduction loss of the switching tubes is reduced, and the conversion efficiency of the converter is improved.

Claims (6)

1. A half-bridge three-level resonant converter comprises an asymmetric three-level bridge arm circuit, a resonant network, a high-frequency isolation transformer and a rectifying and filtering circuit which are sequentially connected in series; the asymmetrical three-level bridge arm circuit is characterized by comprising a first group of switching tubes, a second group of switching tubes, a third switching tube and a fourth switching tube which are sequentially connected in series; the first group of switching tubes and the second group of switching tubes are respectively formed by connecting N switching tubes in parallel, and N is more than or equal to 2; the drain electrode of the first group of switching tubes is connected with a power supply, and the source electrode of the fourth switching tube is grounded; the drain electrode of the third switching tube and the source electrode of the fourth switching tube are respectively connected to the input end of the resonant network; the flying capacitor is connected across the source electrodes of the first group of switching tubes and the source electrode of the third switching tube.
2. A half-bridge three-level resonant converter as claimed in claim 1, characterized in that the resonant network is an LLC resonant circuit or an LCC resonant circuit.
3. The method as claimed in claim 1, wherein the N switching transistors of the first group of switching transistors and the N switching transistors of the second group of switching transistors are separately controlledAdding
Figure FDA0003179176840000011
A drive signal of a duty cycle; the phase of the driving signal of the first switch tube of the second group of switch tubes is lagged behind the phase of the driving signal of the first switch tube of the first group of switch tubes
Figure FDA0003179176840000012
And the number of the first and second electrodes,
the phase of the driving signal of the second switch tube of the first group of switch tubes is lagged behind the phase of the driving signal of the first switch tube of the second group of switch tubes
Figure FDA0003179176840000013
And the number of the first and second electrodes,
the phase of the driving signal of the second switch tube of the second group of switch tubes is lagged behind the phase of the driving signal of the second switch tube of the first group of switch tubes
Figure FDA0003179176840000014
The rest is analogized;
the driving signal of the third switch tube is a complementary signal of the driving signals of the N switch tubes of the second group of switch tubes after logical OR operation;
the driving signal of the fourth switching tube is a complementary signal of the driving signals of the N switching tubes of the first group of switching tubes after logical OR operation.
4. A half-bridge three-level resonant converter comprises an asymmetric three-level bridge arm circuit, a resonant network, a high-frequency isolation transformer and a rectifying and filtering circuit which are sequentially connected in series; the asymmetrical three-level bridge arm circuit is characterized by comprising a first switching tube, a second switching tube, a third switching tube and a fourth switching tube which are sequentially connected in series; the third group of switching tubes and the fourth group of switching tubes are respectively formed by connecting N switching tubes in parallel, and N is more than or equal to 2; the drain electrode of the first switch tube is connected with a power supply, and the source electrode of the fourth switch tube is grounded; the drain electrode of the first switching tube and the source electrode of the second switching tube are respectively connected to the input end of the resonant network; the flying capacitor is connected across the source electrode of the first switch tube and the source electrode of the third switch tube.
5. A half-bridge three-level resonant converter as claimed in claim 4, characterized in that the resonant network is an LLC resonant circuit or an LCC resonant circuit.
6. The method as claimed in claim 4, wherein the N switching transistors of the third set of switching transistors and the N switching transistors of the fourth set of switching transistors are applied respectively
Figure FDA0003179176840000021
A drive signal of a duty cycle; and the number of the first and second electrodes,
the phase of the driving signal of the first switch tube of the third group of switch tubes is lagged behind that of the driving signal of the first switch tube of the fourth group of switch tubes
Figure FDA0003179176840000022
And the number of the first and second electrodes,
the phase of the driving signal of the second switch tube of the fourth group of switch tubes is lagged behind the phase of the driving signal of the first switch tube of the third group of switch tubes
Figure FDA0003179176840000023
And the number of the first and second electrodes,
the phase of the driving signal of the second switch tube of the third group of switch tubes is lagged behind that of the driving signal of the second switch tube of the fourth group of switch tubes
Figure FDA0003179176840000024
The rest is analogized;
the driving signal of the first switching tube is a complementary signal of the driving signals of the N switching tubes of the fourth group of switching tubes after logical OR operation;
the driving signal of the second switch tube is a complementary signal of the driving signals of the N switch tubes of the third group of switch tubes after logical OR operation.
CN202110841857.6A 2021-07-26 2021-07-26 Half-bridge three-level resonant converter and control method thereof Pending CN113541502A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110841857.6A CN113541502A (en) 2021-07-26 2021-07-26 Half-bridge three-level resonant converter and control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110841857.6A CN113541502A (en) 2021-07-26 2021-07-26 Half-bridge three-level resonant converter and control method thereof

Publications (1)

Publication Number Publication Date
CN113541502A true CN113541502A (en) 2021-10-22

Family

ID=78120711

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110841857.6A Pending CN113541502A (en) 2021-07-26 2021-07-26 Half-bridge three-level resonant converter and control method thereof

Country Status (1)

Country Link
CN (1) CN113541502A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113991989A (en) * 2021-12-27 2022-01-28 深圳市永联科技股份有限公司 Current ripple adjusting unit and related product

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170324326A1 (en) * 2016-04-11 2017-11-09 Tianshu Liu Two-phase three-level converter and controller therefor
CN108964478A (en) * 2018-09-19 2018-12-07 矽力杰半导体技术(杭州)有限公司 Mode of resonance switch converters
TWI683522B (en) * 2018-10-24 2020-01-21 林景源 High frequency time-division multi-phase power converter
US20210067045A1 (en) * 2019-08-26 2021-03-04 Delta Electronics, Inc. Three-level modulation for wide output voltage range isolated dc/dc converters
CN112838766A (en) * 2021-01-06 2021-05-25 西南交通大学 High-voltage-reduction-ratio three-level LLC resonant converter and control method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170324326A1 (en) * 2016-04-11 2017-11-09 Tianshu Liu Two-phase three-level converter and controller therefor
CN108964478A (en) * 2018-09-19 2018-12-07 矽力杰半导体技术(杭州)有限公司 Mode of resonance switch converters
TWI683522B (en) * 2018-10-24 2020-01-21 林景源 High frequency time-division multi-phase power converter
US20210067045A1 (en) * 2019-08-26 2021-03-04 Delta Electronics, Inc. Three-level modulation for wide output voltage range isolated dc/dc converters
CN112838766A (en) * 2021-01-06 2021-05-25 西南交通大学 High-voltage-reduction-ratio three-level LLC resonant converter and control method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TIANSHU LIU，ETAL: "A Novel Asymmetrical Three-Level BUCK (ATL", 《2015 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113991989A (en) * 2021-12-27 2022-01-28 深圳市永联科技股份有限公司 Current ripple adjusting unit and related product

Similar Documents

Publication Publication Date Title
CN110401350B (en) Phase-shift control method for full-load range ZVS of double-active full-bridge bidirectional DC-DC converter
CN110768535B (en) Wide gain control method of variable topology LLC resonant converter
CN107346941B (en) Soft switch bidirectional phase shift converter with expanded load range
TWI382642B (en) Resonant circuit with narrow operating frequency band and resonant power converter
CN110707931A (en) LLC resonant converter and control method
CN112234835B (en) Variable structure combined LLC resonant converter
CN111431415B (en) High-boost isolated DC converter with parallel input and series output
CN112838766A (en) High-voltage-reduction-ratio three-level LLC resonant converter and control method thereof
US11539309B2 (en) Zero-voltage zero-current soft switching type driving method for ultrasonic driving unit
CN114337344A (en) Control method based on self-adaptive hybrid rectification multi-switch resonant LLC converter
CN111697841A (en) Converter circuit
CN114157150B (en) High-gain bidirectional Y source-LLC isolated DC-DC converter
CN113541502A (en) Half-bridge three-level resonant converter and control method thereof
CN115133781B (en) Multimode three bridge arm DC-DC converter
CN111525803B (en) Conversion device
CN116111830A (en) Half-bridge-full-bridge combined LLC resonant direct-current converter based on double transformers
CN109742957A (en) A kind of bicyclic complex resonance type soft switch transducer
CN114665720A (en) Bidirectional series resonant converter and improved intermittent sinusoidal modulation method thereof
CN209982343U (en) Circuit structure for realizing wide-gain FB-HB LLC resonant converter
CN112054689A (en) Isolated three-level direct current converter
CN113890375A (en) Bipolar output bidirectional LLC resonant converter topology
Jin et al. Hybrid Control for Three-Level LLC Resonant Converter of Dual-Bridge for Wide Output Range
CN217883231U (en) Full-half-bridge resonant converter structure based on controllable switched capacitor
CN114006535B (en) Bidirectional three-level current-doubling LCL-T resonant converter circuit
TWI823250B (en) Bidirectional dc-dc energy converter with isolation

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
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20211022

WD01 Invention patent application deemed withdrawn after publication