CN113949277A - Wide gain control method of boost integrated CLLLC resonant converter - Google Patents

Wide gain control method of boost integrated CLLLC resonant converter Download PDF

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CN113949277A
CN113949277A CN202111187976.0A CN202111187976A CN113949277A CN 113949277 A CN113949277 A CN 113949277A CN 202111187976 A CN202111187976 A CN 202111187976A CN 113949277 A CN113949277 A CN 113949277A
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frequency
converter
dpwm
switch tube
resonant
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李小强
马永超
伍小杰
黄金伟
徐荣姬
王心潭
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China University of Mining and Technology CUMT
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China University of Mining and Technology CUMT
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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
    • H02M3/33584—Bidirectional converters
    • 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
    • H02M3/22—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
    • 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 wide gain control method of a boost integration type CLLLC resonant converter, which specifically comprises two modulation modes of fixed-frequency synchronous DPWM and variable-frequency DPWM, wherein the fixed-frequency synchronous DPWM method can enable the converter to obtain a high-voltage gain upper limit, and the variable-frequency DPWM method can enable the converter to obtain a low-voltage gain lower limit; the modulation modes of the fixed-frequency synchronous DPWM method or the variable-frequency DPWM method both comprise: switch tube S1Switch tube S3The duty ratios are the same and are all D1And the phase difference of the two driving signals is 180 degrees; switch tube S5Switch tube S7The duty ratios are the same and are all D2And the phase difference of the two driving signals is 180 degrees; and the upper tubes of all the bridge arms are in complementary conduction with the lower tubes. In addition, the switch tube S in the fixed frequency synchronous DPWM method1/S3Respectively with the switching tube S5/S7The driving waveforms have the same fundamental wave phase, and the switching tube S in the frequency conversion DPWM method2/S4Respectively connected with a switch tube S6/S8Compared with the traditional modulation method, the method has lower current stress and wider voltage gain range with the same turn-off time, and increases the practicability of the converter.

Description

Wide gain control method of boost integrated CLLLC resonant converter
Technical Field
The invention belongs to the technical field of power electronics, and particularly relates to a wide gain control method for an interleaved Boost integrated CLLLC resonant converter.
Background
The bidirectional isolation type DC-DC converter is an important power electronic device which is connected with a distributed energy storage and power generation unit in a direct-current microgrid and a direct-current voltage bus. In recent years, with the large-scale popularization of electric vehicles and the continuous development of distributed power generation and energy storage systems and uninterruptible power supplies, bidirectional isolated DC-DC converters are more and more widely used. Meanwhile, the industry also puts higher and higher requirements on the power density, efficiency and voltage regulation range of the power transformer.
The interleaved Boost integrated CLLLC resonant converter is integrated by the current mainstream CLLLC resonant converter topology and the interleaved Boost topology, and has the following advantages: the zero-voltage conduction can be realized under high switching frequency, and the characteristics of high power density and high efficiency are achieved; the high-voltage-gain-ratio converter consists of a front-stage interleaved Boost converter and a rear-stage CLLLC resonant converter, the total voltage gain is the product of the voltage gains of the front-stage interleaved Boost converter and the rear-stage CLLLC resonant converter, and high voltage gain can be output. However, the lower limit of the voltage gain in the forward direction of the topology is high, and it is difficult to meet the requirement of a wide voltage gain range.
The voltage gain of the traditional modulation method of the resonant converter, such as frequency conversion control and phase shift control, is related to the load, and the voltage gain range is narrow when the load is heavy, and the voltage gain range is also narrow when the synchronous PWM control is performed, such as the current stress limitation. Therefore, the conventional modulation method cannot enable the interleaved Boost integrated CLLLC resonant converter to realize wide voltage gain range operation.
Disclosure of Invention
In view of the above-mentioned technical shortcomings, an object of the present invention is to provide a wide gain control method for a boost integrated CLLLC resonant converter, which can widen the soft switching range of the converter, reduce the current stress of the converter, simplify the design of the converter parameters, and widen the voltage gain range of the converter.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention provides a wide gain control method of a boost integration type CLLLC resonant converter, which consists of two modulation modes of fixed-frequency synchronous DPWM and variable-frequency DPWM, wherein the converter obtains a high-voltage gain upper limit by the fixed-frequency synchronous DPWM method, and obtains a low-voltage gain lower limit by the variable-frequency DPWM method; the control modes of the fixed-frequency synchronous DPWM method or the variable-frequency DPWM method both comprise: switch tube S1Switch tube S3The duty ratios are the same and are all D1And the phase difference of the two driving signals is 180 degrees; switch tube S5Switch tube S7The duty ratios are the same and are all D2And the phase difference of the two driving signals is 180 degrees; and the upper tubes of all the bridge arms are in complementary conduction with the lower tubes.
Preferably, the difference delta between fixed duty cycles of the synchronous DPWM control during working is selected according to the standard of soft switching under rated power1Delta difference from the fixed duty cycle of the variable frequency DPWM control during operation2At (0, 0.5)]Control with constant frequency synchronous DPWM in the duty ratio range, D2＝D1+δ1Voltage gain with D1Rises and falls when D2When rising to 0.5, D2Held constant at 0.5, D2And D1No longer maintain the duty ratio difference delta1，D1Can continue to rise until D1＝D2When D is equal to 0.5, the converter voltage gain is 21And when the voltage continues to rise, the modulation mode is switched from constant-frequency synchronous DPWM control to variable-frequency DPWM control, the voltage reduction of the rear-stage CLLLC resonant converter is started, and the voltage gain is along with D1Rising and falling, D1Initial stage of ascent, D2It remains 0.5 constant until D2＝D1-δ2Then, D2And D1Maintaining the difference delta2Simultaneously ascending; when D is present1When it rises to 0.75, D1Held constant at 0.75, D2And D1No longer maintain the duty ratio difference delta2，D2Can continue to rise until D1＝D2At 0.75, the converter achieves the lowest voltage gain.
Preferably, the fixed frequency in the fixed frequency synchronous DPWM method is embodied in that the working frequency is fixed at the resonant frequency, and the corresponding parameter relationship is as follows:
Figure BDA0003300075370000021
in formula (1): f. ofsIs the switching frequency; f. ofrIs the resonant frequency; l isrFor the resonant inductance parameter, Lr＝Lr1＝Lr2；CrAs a resonant capacitance parameter, Cr＝Cr1＝Cr2。
Preferably, the frequency conversion in the variable frequency DPWM method is embodied in the duty cycle D1And the switching frequency fsThe linear relation corresponds to the parameter relation:
fs＝2(1-D1)fr (2)
in formula (2): f. ofsIs the switching frequency; f. ofrTo the resonant frequency, D1Is a switch tube S1Switch tube S3Duty cycle.
Preferably, the fixed frequency synchronous DPWM method further comprises: switch tube S1/S3Respectively with the switching tube S5/S7Have the same fundamental phase; the variable frequency DPWM method further comprises: switch tube S2/S4Respectively connected with a switch tube S6/S8With the same off-time.
Preferably, the topological structure of the converter comprises a preceding converter and a following converter, the preceding converter is an interleaved Boost bidirectional DC-DC converter, and the following converter is a CLLLC resonant converter.
Preferably, two ends of the CLLLC resonant converter are respectively an output-side dc bus and a middle-stage dc bus, two ends of the dc bus are respectively butted with two full bridges, each full bridge is formed by two sets of series-connected full bridgesThe two switch tubes are connected in parallel, and a lead is led out from the midpoint of each group of the switch tubes connected in series and is connected with the resonant cavity; the resonant cavity is a two-port network, one port is connected with the middle points of the two bridge arms of the input side full bridge, and the other port is connected with the middle points of the two bridge arms of the output side full bridge; a transformer is arranged in the middle of the resonant cavity, and a resonant inductor L is connected in series on the primary side of the transformerr1And a resonance capacitor Cr1(ii) a The secondary side of the transformer is connected in series with a resonance inductor Lr2And a resonance capacitor Cr2。
Preferably, two ends of the interleaved Boost bidirectional DC-DC converter are an input-side DC bus and a middle-stage DC bus, respectively, and two ends of the input-side DC bus pass through two input inductors L1、L2And the alternating Boost bidirectional DC-DC converters are respectively connected with the middle points of the input side full bridges and finally form a front-stage interleaved Boost bidirectional DC-DC converter with the input side full bridges and the middle-stage direct-current bus.
The invention has the beneficial effects that: .
The method can widen the soft switching range of the interleaved Boost integrated CLLLC resonant converter, reduce the current stress of the converter, simplify the parameter design of the converter and widen the voltage gain range of the converter.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a topological diagram of an interleaved Boost integrated bidirectional CLLLC resonant converter;
FIG. 2 is a schematic diagram of the working waveform of the fixed-frequency synchronous DPWM method of the present invention;
FIG. 3 shows the voltage gain G of the down converter of the constant frequency synchronous DPWM method of the present inventiontotalWith duty cycle D1、D2Changing the three-dimensional map;
FIG. 4 is a schematic diagram of the operating waveform of the variable frequency DPWM method of the present invention;
FIG. 5 is a voltage gain curve obtained from a simulation example under the variable frequency DPWM method of the present invention;
FIG. 6 is a working waveform under a fixed frequency synchronous DPWM method;
FIG. 7 is a diagram illustrating the operation waveforms under the conventional constant-frequency synchronous PWM control;
fig. 8 is a working waveform under the variable frequency DPWM method.
The symbols and designations in the drawings indicate: u shapei-a power supply side input voltage; u shapezThe intermediate stage voltage is the output voltage of the front stage and is also the input voltage of the rear stage; u shapeo-a load side output voltage; i.e. io-load side output current; u. ofab-the resonant tank voltage of the primary side of the transformer; u. ofcd-the resonant tank voltage of the secondary side of the transformer; l ism-an excitation inductance; l isr1-a primary resonant inductance of the transformer; l isr2-secondary resonant inductance of the transformer; l is1、L2-an input side inductance; i.e. i1-resonant inductance Lr1Current flow; i.e. i2-resonant inductance Lr2Current flow; i.e. imExcitation inductance LmCurrent flow; i.e. iL1Inductance L1Current flow; i.e. iL2Inductance L2Current flow; cr1-a primary resonant capacitor of the transformer; cr2-secondary resonant capacitance of the transformer; u. of1-resonant capacitor Cr1A voltage; u. of2-resonant capacitor Cr2A voltage; ci-a power supply side filter capacitance; cz-an intermediate stage filter capacitor; co-an output side filter capacitance; d1Switching tube S1Switch tube S3A duty cycle; d2Switching tube S5Switch tube S7A duty cycle; gtotal-converter total voltage gain; ro-a load resistance; delta-D1And D2The absolute value of the deviation therebetween; f. ofs-operating frequency.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment provides a wide gain control method of a boost integration type CLLLC resonant converter, which specifically comprises two modulation modes of fixed-frequency synchronous DPWM and variable-frequency DPWM, wherein the fixed-frequency synchronous DPWM method can enable the converter to obtain a high-voltage gain upper limit, and the variable-frequency DPWM method can enable the converter to obtain a low-voltage gain lower limit; the control modes of the fixed-frequency synchronous DPWM method or the variable-frequency DPWM method both comprise: switch tube S1Switch tube S3The duty ratios are the same and are all D1And the phase difference of the two driving signals is 180 degrees; switch tube S5Switch tube S7The duty ratios are the same and are all D2And the phase difference of the two driving signals is 180 degrees; and the upper tubes of all the bridge arms are in complementary conduction with the lower tubes. In addition, the switch tube S in the fixed frequency synchronous DPWM method1/S3Respectively with the switching tube S5/S7The driving waveforms have the same fundamental wave phase, and the switching tube S in the frequency conversion DPWM method2/S4Respectively connected with a switch tube S6/S8With the same off-time.
The topological structure of the interleaved Boost integrated CLLLC resonant converter of the present embodiment is shown in fig. 1, and is composed of two parts, the front stage is an interleaved Boost bidirectional DC-DC converter, the rear stage is a CLLLC resonant converter, two ends of the CLLLC resonant converter at the rear stage are an output side direct current bus and a middle stage direct current bus respectively, two ends of the direct current bus are respectively butted with two full bridges, each full bridge is formed by connecting two groups of series-connected switching tubes in parallel, and a lead is led out from the midpoint of each group of series-connected switching tubes to connect with a resonant cavity; the resonant cavity is a two-port network, one port is connected with the middle points of the two bridge arms of the input side full bridge, and the other port is connected with the middle points of the two bridge arms of the output side full bridge; a transformer is arranged in the middle of the resonant cavity, and a resonant inductor L is connected in series on the primary side of the transformerr1And a resonance capacitor Cr1(ii) a The secondary side of the transformer is connected in series with a resonance inductor Lr2And a resonance capacitor Cr2. Preceding stage crossingTwo ends of the staggered Boost bidirectional DC-DC converter are respectively an input side direct current bus and a middle level direct current bus, and two ends of the input side direct current bus pass through two input inductors L1、L2Respectively connected to the midpoints of the input side full bridges.
The specific control mode of the fixed-frequency synchronous DPWM method in this embodiment is as follows: switch tube S1、S3The duty ratios are the same and are all D1And the phase difference of the two driving signals is 180 degrees; switch tube S5、S7The duty ratios are the same and are all D2And the phase difference of the two driving signals is 180 degrees; s1、S3Respectively with S5、S7Have the same fundamental phase; and the upper tubes of all the bridge arms are in complementary conduction with the lower tubes. The switching frequency is:
Figure BDA0003300075370000051
in formula (1): f. ofsIs the switching frequency; f. ofrIs the resonant frequency; l isrFor the resonant inductance parameter, Lr＝Lr1＝Lr2；CrAs a resonant capacitance parameter, Cr＝Cr1＝Cr2。
The duty ratio regulation range of the fixed-frequency synchronous DPWM method is (0, 0.5)]D is ensured when the duty ratio is adjusted1And D2The difference is small and is not more than 0.1 at most. The relevant operating waveforms are shown in fig. 2.
FIG. 3 is a three-dimensional graph of voltage gain for the fixed frequency synchronous DPWM method, plotted according to the voltage gain expression shown in equation (2).
Figure BDA0003300075370000061
In formula (2): gtotal-converter total voltage gain; d1Switching tube S1Switch tube S3A duty cycle; d2Switching tube S5Switch tube S7A duty cycle;
the soft switching conditional expression of the fixed-frequency synchronous DPWM method is as follows:
Figure BDA0003300075370000062
in the formula (3), F is a soft switching condition parameter; u shapeiIs the power supply side input voltage; zr＝(Lr/Cr)0.5As an auxiliary parameter, D1Switching tube S1Switch tube S3A duty cycle; d2Switching tube S5Switch tube S7A duty cycle; l isrIs a resonant inductor Lr1、Lr2A value of (d); crIs a resonant capacitor Cr1、Cr2A value of (d); k is Lm/Lr，LmIs an excitation inductor; p1Is the input power; p2Is the output power; cossThe equivalent capacitor is connected with the switching tube in parallel; t isdIs the dead time.
When F >0, soft switching can be achieved. The soft switching conditional expression is an important basis for designing resonance parameters of the down converter by the fixed-frequency synchronous DPWM method.
The variable-frequency DPWM method described in this embodiment widens the lower limit of the voltage gain of the converter, and the specific control method is as follows: switch tube S1、S3The duty ratios are the same and are all D1And the phase difference of the two driving signals is 180 degrees; switch tube S5、S7The duty ratios are the same and are all D2And the phase difference of the two driving signals is 180 degrees; the upper tubes of all bridge arms are in complementary conduction with the lower tubes; s2、S4Respectively with S6、S8Have the same off-time. The switching frequency is:
fs＝2(1-D1)fr (4)
in formula (4): f. ofsTo the switching frequency, frTo the resonant frequency, D1Is a switch tube S1Switch tube S3A duty cycle; the duty ratio satisfies that D2 is more than or equal to 0.5 and less than or equal to D1 is more than or equal to 0.75. The relevant operating waveforms are shown in fig. 4.
The accurate voltage gain expression of the variable frequency DPWM method is difficult to derive, and L is used in the embodimentr＝5μH，CrA simulation example was constructed for the resonance parameter of 500nH, and the measured voltage gain curve is shown in fig. 5. Wherein delta2Is D1And D2Absolute value of deviation, same duty cycle D1When is below delta2At 0, the voltage gain of the variable frequency DPWM method is lowest, but δ needs to be increased when soft switching cannot be achieved2To achieve soft switching.
As can be seen from fig. 5(a), the voltage gain curve of the variable frequency DPWM method is affected by the load, the smaller the load resistance, the larger the load, and the easier the converter can achieve low voltage gain, but the larger the load, the more difficult the soft switching can be achieved, and the need to increase δ2To achieve soft switching. On the other hand, as shown in FIG. 5(b), when the load resistance is fixed to 50. omega., δ2The larger the overall voltage gain of the variable frequency DPWM method. From the above, the overall voltage gain of the variable frequency DPWM method decreases with increasing load, and with δ2Increase and rise, but larger delta2The values will generally match larger loads, so the voltage gain curves do not differ too much from load to load in the case of soft switching.
The specific implementation manner of the wide gain control method described in this embodiment is as follows: selecting the difference delta between fixed duty ratios when the synchronous DPWM control works based on the standard of realizing soft switching under rated power1Delta difference from the fixed duty cycle of the variable frequency DPWM control during operation2At (0, 0.5)]Control with constant frequency synchronous DPWM in the duty ratio range, D2＝D1+δ1Voltage gain with D1Rises and falls when D2When rising to 0.5, D2Held constant at 0.5, D2And D1No longer maintain the duty ratio difference delta1，D1Can continue to rise until D1＝D2When D is equal to 0.5, the converter voltage gain is 21And when the voltage continues to rise, the modulation mode is switched from constant-frequency synchronous DPWM control to variable-frequency DPWM control, the voltage reduction and voltage increase of the rear-stage CLLLC resonant converter are startedYifollow D1Rising and falling, D1Initial stage of ascent, D2It remains 0.5 constant until D2＝D1-δ2Then, D2And D1Maintaining the difference delta2While rising. When D is present1When it rises to 0.75, D1Held constant at 0.75, D2And D1No longer maintain the duty ratio difference delta2，D2Can continue to rise until D1＝D2At 0.75, the converter voltage gain is lowest.
This embodiment uses Lr＝5μH,Cr＝500nH，Lm＝100μH，L1＝L2＝200μH，Ci＝Cz＝CoAn experiment was performed by setting up an experimental platform for the transducer parameters of 150 μ H, and fig. 6, 7, and 8 were obtained.
In the experimental example, the duty ratio range in which the wide gain control method is set according to the practical situation of the experimental platform is [0.2,0.75 ]]FIG. 6 is a graph of the converter voltage gain upper limit waveform obtained using the fixed frequency synchronous DPWM method, at which time D1＝0.2，D2The input voltage is 48.8V, the output voltage is 204V, and the voltage gain is 4.18, which is 0.23.
FIG. 7 is a waveform diagram obtained by conventional fixed-frequency synchronous PWM control under the same experimental platform parameters, at which time D1＝0.2，D2Fixed at 0.5, input voltage at 49.1V, output voltage at 142V, and voltage gain at 2.89. It can be seen from the figure that the experimental platform designed according to the fixed-frequency synchronous DPWM method is not suitable for using the conventional fixed-frequency synchronous PWM control, otherwise, an excessive resonant current spike is generated, and if the conventional fixed-frequency synchronous PWM control is used, the resonant inductance value must be increased, which inevitably reduces the soft switching range of the converter. In summary, the fixed-frequency synchronous DPWM method of the present embodiment has obvious advantages compared with the conventional fixed-frequency synchronous PWM control.
FIG. 8 is a graph of the converter voltage gain lower limit waveform obtained using the variable frequency DPWM method, where D1＝0.75，D20.73, load 50 Ω, input voltage 50V, output voltage 10.6V, and voltage gain 0.212. The method shows that the variable-frequency DPWM method can realize good voltage reduction effect.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present embodiment without departing from the spirit and scope of the embodiment. Thus, the present embodiment is intended to include such modifications and variations provided they come within the scope of the claims of the present embodiment and their equivalents.

Claims (8)

1. The wide gain control method of the boost integration CLLLC resonant converter is characterized by comprising two modulation modes of fixed-frequency synchronous DPWM and variable-frequency DPWM, wherein the converter obtains a high-voltage gain upper limit by the fixed-frequency synchronous DPWM method and obtains a low-voltage gain lower limit by the variable-frequency DPWM method; the control modes of the fixed-frequency synchronous DPWM method or the variable-frequency DPWM method both comprise: switch tube S1Switch tube S3The duty ratios are the same and are all D1And the phase difference of the two driving signals is 180 degrees; switch tube S5Switch tube S7The duty ratios are the same and are all D2And the phase difference of the two driving signals is 180 degrees; and the upper tubes of all the bridge arms are in complementary conduction with the lower tubes.
2. The wide gain control method of boost integrated CLLLC resonant converter according to claim 1, characterized in that the difference δ of fixed duty cycle when the synchronous DPWM control is operated is selected based on soft switching at rated power1Delta difference from the fixed duty cycle of the variable frequency DPWM control during operation2At (0, 0.5)]Control with constant frequency synchronous DPWM in the duty ratio range, D2＝D1+δ1Voltage gain with D1Rises and falls when D2When rising to 0.5, D2Held constant at 0.5, D2And D1No longer maintain the duty ratio difference delta1，D1Can continue to rise until D1＝D2When D is equal to 0.5, the converter voltage gain is 21When the modulation mode continues to rise, the modulation mode is switched from the constant-frequency synchronous DPWM control to the variable-frequency DPWM control, and the rear-stage CLLLC harmonic begins to be subjected toThe vibration converter performs voltage reduction with voltage gain following D1Rising and falling, D1Initial stage of ascent, D2It remains 0.5 constant until D2＝D1-δ2Then, D2And D1Maintaining the difference delta2Simultaneously ascending; when D is present1When it rises to 0.75, D1Held constant at 0.75, D2And D1No longer maintain the duty ratio difference delta2，D2Can continue to rise until D1＝D2At 0.75, the converter achieves the lowest voltage gain.
3. The wide gain control method of the boost integrated CLLLC resonant converter as claimed in claim 1, wherein the fixed frequency in the fixed frequency synchronous DPWM method is embodied at a position where its operating frequency is fixed at the resonant frequency, and the corresponding parameter relationship is:
Figure FDA0003300075360000011
in formula (1): f. ofsIs the switching frequency; f. ofrIs the resonant frequency; l isrFor the resonant inductance parameter, Lr＝Lr1＝Lr2；CrAs a resonant capacitance parameter, Cr＝Cr1＝Cr2。
4. The wide gain control method of a boost integrated CLLLC resonant converter as claimed in claim 1, characterized in that the frequency conversion in said frequency conversion DPWM method is embodied in duty cycle D1And the switching frequency fsThe linear relation corresponds to the parameter relation:
fs＝2(1-D1)fr (2)
in formula (2): f. ofsIs the switching frequency; f. ofrTo the resonant frequency, D1Is a switch tube S1Switch tube S3Duty cycle.
5. The liter of claim 1The wide gain control method of the voltage integration type CLLLC resonant converter is characterized in that the fixed frequency synchronous DPWM method further comprises the following steps: switch tube S1/S3Respectively with the switching tube S5/S7Have the same fundamental phase; the variable frequency DPWM method further comprises: switch tube S2/S4Respectively connected with a switch tube S6/S8With the same off-time.
6. The wide gain control method of a Boost integrated CLLLC resonant converter as claimed in claim 1, wherein the topology of said converter includes a pre-stage converter, a post-stage converter, said pre-stage converter being an interleaved Boost bidirectional DC-DC converter, said post-stage converter being a CLLLC resonant converter.
7. The wide gain control method of the boost integrated CLLLC resonant converter according to claim 6, wherein two ends of the CLLLC resonant converter are respectively an output side direct current bus and a middle stage direct current bus, two ends of the direct current bus are respectively butted with two full bridges, each full bridge is formed by connecting two groups of serially connected switch tubes in parallel, and a lead is led out from the midpoint of each group of serially connected switch tubes to connect with the resonant cavity; the resonant cavity is a two-port network, one port is connected with the middle points of the two bridge arms of the input side full bridge, and the other port is connected with the middle points of the two bridge arms of the output side full bridge; a transformer is arranged in the middle of the resonant cavity, and a resonant inductor L is connected in series on the primary side of the transformerr1And a resonance capacitor Cr1(ii) a The secondary side of the transformer is connected in series with a resonance inductor Lr2And a resonance capacitor Cr2。
8. The wide gain control method of the Boost integrated CLLLC resonant converter according to claim 6, wherein two ends of the interleaved Boost bidirectional DC-DC converter are an input side direct current bus and a middle stage direct current bus respectively, and two ends of the input side direct current bus pass through two input inductors L1、L2Respectively connected with the middle point of the input side full bridge, and finally formed with the input side full bridge and the intermediate stage direct current busAnd the interleaved Boost bidirectional DC-DC converter of the front stage.
CN202111187976.0A 2021-10-12 2021-10-12 Wide gain control method of boost integrated CLLLC resonant converter Pending CN113949277A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116155108A (en) * 2023-01-04 2023-05-23 深圳市迪威电气有限公司 Control method of bidirectional LLC resonant DC converter capable of stabilizing voltage in wide range

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116155108A (en) * 2023-01-04 2023-05-23 深圳市迪威电气有限公司 Control method of bidirectional LLC resonant DC converter capable of stabilizing voltage in wide range
CN116155108B (en) * 2023-01-04 2023-10-24 深圳市迪威电气有限公司 Control method of bidirectional LLC resonant DC converter capable of stabilizing voltage in wide range

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