CN110880872B - Bidirectional self-driven DC-DC converter - Google Patents
Bidirectional self-driven DC-DC converter Download PDFInfo
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- CN110880872B CN110880872B CN201911167108.9A CN201911167108A CN110880872B CN 110880872 B CN110880872 B CN 110880872B CN 201911167108 A CN201911167108 A CN 201911167108A CN 110880872 B CN110880872 B CN 110880872B
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- 230000002457 bidirectional effect Effects 0.000 title claims abstract description 82
- 239000003990 capacitor Substances 0.000 claims description 11
- 230000001360 synchronised effect Effects 0.000 abstract description 15
- 238000005516 engineering process Methods 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 21
- 238000000034 method Methods 0.000 description 8
- 238000012545 processing Methods 0.000 description 5
- 230000000295 complement effect Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 239000002803 fossil fuel Substances 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
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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
- H02M3/3353—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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The embodiment of the invention discloses a bidirectional self-driven DC-DC converter, which comprises a high-voltage side full-bridge circuit unit, a resonant network unit, a transformer unit and a low-voltage side bridge circuit unit, wherein the resonant network unit is connected with the transformer unit; the switching tubes included in the high-voltage side full-bridge circuit unit are connected with the high-voltage side self-driving circuit unit, and the switching tubes included in the low-voltage side full-bridge circuit unit are connected with the low-voltage side self-driving circuit unit. The switch tube of the corresponding rectification part adopts a self-driving mode no matter in a forward working state or a reverse working state, and the switch tube of the corresponding inversion part adopts other driving modes, so that a software control strategy of a synchronous rectification driving technology of the bidirectional LLC converter is simplified, a special synchronous rectification chip is not required to be used, and a self-driving circuit structure is simplified.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a bidirectional self-driven DC-DC converter.
Background
The use of a large amount of fossil fuel causes more and more serious environmental pollution. Such as "greenhouse effect", various extreme weather conditions, and man-made pollution, are closely related to the heavy use of fossil fuels. Under the pressure of the problems, countries have begun to accelerate the development of new energy sources, and in particular, research on renewable energy sources has been increased.
In recent years, the micro-grid and electric automobile industries are developed vigorously, and the development of power electronic converters is driven. Bidirectional DC/DC converters (i.e., bidirectional DC-DC converters) are widely used in the fields of hybrid energy storage in micro-grids, electric vehicles, bidirectional charging piles, and the like. In a new energy power generation system, a storage battery, a super capacitor and the like are often required to ensure stable energy supply. Taking photovoltaic power generation as an example, when the amount of electricity generated by photovoltaic is more than the energy which needs to be supplied to the power grid, a part of the energy is stored in the storage battery through the DC/DC converter. When the power consumption peak period or the light source is insufficient at night, the storage battery releases energy into the power grid through the DC/DC converter, so that the effective utilization and reasonable supply of the energy are fully ensured.
As the bidirectional DC/DC converter for the electric vehicle, a circuit topology as shown in fig. 1 and 2 is generally adopted. For the bidirectional DC/DC converter with circuit topology as shown in fig. 1 and fig. 2, in the prior art, the on and off of the primary and secondary side switching tubes of the converter are mainly controlled by software to realize synchronous rectification control. The synchronous rectification technique can cause the problem of current backflow when the switching frequency fs is less than the resonance frequency fr. When the problem of current back-flow is solved, the current direction of the rectifier switch tube needs to be detected, and therefore the matching of a hardware detection circuit and a software algorithm is needed. The mode of controlling the on and off of the switch tube through software not only has a complex software control strategy, but also needs to add a current detection circuit and a special drive chip of the switch tube, and has a complex circuit structure.
Disclosure of Invention
The embodiment of the invention provides a bidirectional self-driven DC-DC converter, aiming at solving the problems that the existing bidirectional DC/DC converter is complex in software control strategy, a current detection circuit and a special drive chip of a switching tube are required to be added, and the circuit structure is complex when the current back-flow problem is generated and the on-off mode of the switching tube is controlled by software.
The invention provides a bidirectional self-driven DC-DC converter, which comprises a high-voltage side full-bridge circuit unit, a resonant network unit, a transformer unit and a low-voltage side bridge circuit unit, wherein the resonant network unit is connected with the transformer unit; the switching tubes included in the high-voltage side full-bridge circuit unit are connected with the high-voltage side self-driving circuit unit, and the switching tubes included in the low-voltage side full-bridge circuit unit are connected with the low-voltage side self-driving circuit unit;
one end of the high-voltage side full-bridge circuit unit is connected with a high-voltage end, and the other end of the high-voltage side full-bridge circuit unit is connected with one end of the resonant network unit;
the other end of the resonant network unit is connected with the primary side of the transformer unit;
the secondary side of the transformer unit is connected with one end of the low-voltage side bridge type circuit unit;
the other end of the low-voltage side bridge circuit unit is connected with a low-voltage end;
in a forward working state of the bidirectional self-driven DC-DC converter, when the high-voltage side full-bridge circuit unit receives a driving signal of the high-voltage side self-driven circuit unit, the high-voltage side full-bridge circuit unit converts the first-state direct current at the high-voltage end sequentially through the high-voltage side full-bridge circuit unit, the resonant network unit, the transformer unit and the low-voltage side bridge circuit unit to obtain a first-state step-down direct current output by the low-voltage end;
in the reverse working state of the bidirectional self-driven DC-DC converter, when the low-voltage side bridge circuit unit receives a driving signal of the low-voltage side self-driven circuit unit, the second-state direct current at the low-voltage end sequentially passes through the low-voltage side bridge circuit unit, the transformer unit, the resonant network unit and the high-voltage side full-bridge circuit unit to be converted, and then the second-state boosting direct current output by the high-voltage end is obtained.
The embodiment of the invention provides a bidirectional self-driven DC-DC converter, wherein switching tubes included in a high-voltage side full bridge circuit unit are connected with a high-voltage side self-driven circuit unit, and switching tubes included in a low-voltage side bridge circuit unit are connected with a low-voltage side self-driven circuit unit, the switching tubes of a corresponding rectifying part adopt a self-driven mode no matter in a forward working state or a reverse working state, the switching tubes of a corresponding inverting part adopt other driving modes, a software control strategy of a bidirectional LLC converter synchronous rectifying driving technology is simplified, a special synchronous rectifying chip is not needed, and a self-driven circuit structure is simplified.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic circuit diagram of a first embodiment of a bidirectional DC/DC converter of an electric vehicle in the prior art;
FIG. 2 is a schematic diagram of a circuit configuration of a second embodiment of a bidirectional DC/DC converter of an electric vehicle in the prior art;
fig. 3 is a schematic structural diagram of a bidirectional self-driven DC-DC converter provided by an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a bidirectional self-driven DC-DC converter according to an embodiment of the present invention;
fig. 5 is a schematic circuit diagram of a first low-side self-driving circuit unit in a bidirectional self-driven DC-DC converter according to an embodiment of the present invention;
fig. 6 is a schematic circuit diagram of a forward operating state of a bidirectional self-driven DC-DC converter according to an embodiment of the present invention;
FIG. 7a is a timing diagram illustrating a switching frequency less than a resonant frequency in a forward operating state of a bidirectional self-driven DC-DC converter according to an embodiment of the present invention;
FIG. 7b is a timing diagram illustrating the switching frequency equal to the resonant frequency in the forward operation state of the bidirectional self-driven DC-DC converter according to the embodiment of the present invention;
FIG. 7c is a timing diagram illustrating the switching frequency being greater than the resonant frequency in the forward operating state of the bidirectional self-driven DC-DC converter according to the embodiment of the present invention;
fig. 8 is a schematic circuit diagram of a reverse operation state of a bidirectional self-driven DC-DC converter according to an embodiment of the present invention;
fig. 9a is a timing chart of a switching frequency less than a resonant frequency in a reverse operation state in a bidirectional self-driven DC-DC converter provided by an embodiment of the present invention;
FIG. 9b is a timing diagram illustrating the switching frequency equal to the resonant frequency in the reverse operation state of the bi-directional self-driven DC-DC converter provided by the embodiment of the present invention;
fig. 9c is a timing diagram illustrating the switching frequency being greater than the resonant frequency in the reverse operation state in the bidirectional self-driven DC-DC converter according to the embodiment of the present invention.
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 some, not all, embodiments of the present invention. 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.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Please refer to fig. 3 and fig. 4, wherein fig. 3 is a schematic structural diagram of a bidirectional self-driven DC-DC converter according to an embodiment of the present invention; fig. 4 is a schematic circuit diagram of a bidirectional self-driven DC-DC converter according to an embodiment of the present invention. As shown in fig. 3 and 4, the bidirectional self-driven DC-DC converter includes:
a high-voltage side full-bridge circuit unit 11, a resonant network unit 12, a transformer unit 13 and a low-voltage side bridge circuit unit 14; the switching tubes included in the high-voltage side full-bridge circuit unit 11 are all connected with a high-voltage side self-driving circuit unit 11a, and the switching tubes included in the low-voltage side bridge circuit unit 14 are all connected with a low-voltage side self-driving circuit unit 14 a;
one end of the high-voltage side full-bridge circuit unit 11 is connected with a high-voltage end 10, and the other end of the high-voltage side full-bridge circuit unit 11 is connected with one end of the resonant network unit 12;
the other end of the resonant network unit 12 is connected with the primary side of the transformer unit 13;
the secondary side of the transformer unit 13 is connected with one end of the low-voltage side bridge circuit unit 14;
the other end of the low-voltage side bridge circuit unit 14 is connected with a low-voltage end 15;
in a forward working state of the bidirectional self-driven DC-DC converter, when the high-side full-bridge circuit unit 11 receives a driving signal of the high-side self-driving circuit unit 11a, the high-side full-bridge circuit unit 11 converts the first-state direct current of the high-voltage end 10 sequentially through the high-side full-bridge circuit unit 11, the resonant network unit 12, the transformer unit 13, and the low-voltage side bridge circuit unit 14 to obtain a first-state step-down direct current output by the low-voltage end 15;
in the reverse working state of the bidirectional self-driven DC-DC converter, when the low-voltage side bridge circuit unit 14 receives the driving signal of the low-voltage side self-driving circuit unit 14a, the second-state direct current of the low-voltage end 15 is converted by the low-voltage side bridge circuit unit 14, the transformer unit 13, the resonant network unit 12, and the high-voltage side full bridge circuit unit 11 in sequence, so as to obtain the second-state boost direct current output by the high-voltage end 10.
The primary side of a transformer unit 13 in the bidirectional self-driven DC-DC converter adopts a full-bridge structure, and the secondary side of the transformer unit 13 adopts a full-wave rectification structure. The primary voltage is set to V1 (i.e., the voltage at the high-voltage end is V1), and the secondary voltage is set to V2 (i.e., the voltage at the low-voltage end is V2). When the bidirectional self-driven DC-DC converter is in a forward working state, the primary side is an input end and V1 is input voltage, the secondary side is an output end and V2 is output voltage. When the bidirectional self-driven DC-DC converter is in a reverse working state, the primary side is an output end and V1 is output voltage, the secondary side is an input end and V2 is input voltage.
The high-voltage side self-driving circuit unit 11a is connected to the primary side driving chip U1, the primary side driving chip U1 is connected to the DSP unit 20, the low-voltage side self-driving circuit unit 14a is connected to the secondary side driving chip U2, and the secondary side driving chip U2 is connected to the DSP unit 20.
When the bidirectional self-driven DC-DC converter is in a forward working state, the DSP unit 20 sends a PWM signal (PWM signal, i.e., pulse width modulation signal) to the primary side driving chip U1, the primary side driving chip U1 outputs a corresponding high-voltage side driving signal to the high-voltage side self-driving circuit unit 11a, and the high-voltage side self-driving circuit unit 11a generates a high-voltage side driving voltage signal according to the high-voltage side driving signal. The high-side driving voltage signal generated by the high-side self-driving circuit unit 11a drives the first-state direct current of the high-side end 10 to sequentially pass through the high-side full-bridge circuit unit 11, the resonant network unit 12, the transformer unit 13 and the low-side bridge circuit unit 14, so as to obtain the first-state step-down direct current output by the low-side end 15. Meanwhile, the DSP unit 20 controls the output voltage of the secondary driving chip U2 to be always at a low level, and at this time, the secondary driving chip U2 drives the low-voltage side self-driving circuit unit 14a to generate a low-voltage side driving voltage signal, and the switching tube in the low-voltage side bridge circuit unit 14 operates in a self-driving mode.
When the bidirectional self-driven DC-DC converter is in a reverse operation state, the DSP unit 20 sends a PWM signal (i.e., a PWM signal) to the secondary driving chip U2, the secondary driving chip U2 outputs a corresponding low-voltage side driving signal to the low-voltage side self-driving circuit unit 14a, and the low-voltage side self-driving circuit unit 14a generates a low-voltage side driving voltage signal according to the low-voltage side driving signal. The low-voltage side driving voltage signal generated by the low-voltage side self-driving circuit unit 14a drives the second-state direct current at the low-voltage end to be converted sequentially through the low-voltage side bridge circuit unit 14, the transformer unit 13, the resonant network unit 12 and the high-voltage side bridge circuit unit 11, so as to obtain the second-state boost direct current output by the low-voltage end 15. Meanwhile, the DSP unit 20 controls the output voltage of the primary side driving chip U1 to be always at a low level, at this time, the primary side driving chip U1 drives the high-voltage side self-driving circuit unit 11a to generate a high-voltage side driving voltage signal, and the switching tubes in the high-voltage side full bridge circuit unit 11 operate in a self-driving mode.
Therefore, the switch tube of the rectification part in the bidirectional self-driven DC-DC converter adopts a self-driving mode, the switch tube of the inversion part adopts a driving mode of generating PWM by DSP, and a software control strategy of a synchronous rectification driving technology of the bidirectional self-driven DC-DC converter is simplified.
Specifically, as shown in fig. 3 and 4, in the forward operation state of the bidirectional self-driven DC-DC converter:
the high-voltage side full-bridge circuit unit 11 is configured to receive a driving signal of the high-voltage side self-driving circuit unit 11a and convert the first-state direct current of the high-voltage terminal 10 into a first-state alternating current;
the resonant network unit 12 is configured to resonate the first state alternating current output by the high-voltage side full bridge circuit unit 11 to obtain a first alternating square wave voltage;
the transformer unit 13 is configured to step down the first ac square wave voltage output by the resonant network unit 12 to obtain a first state step-down ac;
the low-voltage side bridge circuit unit 14 is configured to convert the first-state step-down ac power output by the transformer unit 13 to obtain a first-state step-down dc power.
Under the forward working state of the bidirectional self-driven DC-DC converter, under the processing of the high-voltage side full-bridge circuit unit 11, converting the first-state direct current of the high-voltage end 10 into a first-state alternating current; under the resonance of the resonance network unit 12, resonating the first state alternating current to obtain a first alternating current square wave voltage; under the voltage reduction processing of the transformer unit 13, the first alternating-current square wave voltage is reduced to obtain first state reduced-voltage alternating current; under the processing of the low-voltage side bridge circuit unit 14, the first-state step-down alternating current is converted to obtain a first-state step-down direct current. The high-voltage side full bridge circuit unit 11 can be regarded as an inverter part of the bidirectional self-driven DC-DC converter, and is driven by the DSP unit 20 sending out a PWM signal; the low-side bridge circuit unit 14 can be regarded as a rectifying part of the bidirectional self-driven DC-DC converter, which operates in a self-driven mode.
Specifically, as shown in fig. 3 and 4, in the reverse operation state of the bidirectional self-driven DC-DC converter:
the low-voltage side bridge circuit unit 14 is configured to receive a driving signal from the low-voltage side self-driving circuit unit 14a and convert the second-state direct current of the low-voltage terminal 15 into a second-state alternating current;
the transformer unit 13 is configured to boost the second-state alternating current output by the low-voltage side bridge circuit unit 14 to obtain second-state boosted alternating current;
the resonant network unit 12 is configured to resonate the boost alternating current in the second state output by the transformer unit 13 to obtain a second alternating square wave voltage;
the high-voltage side full-bridge circuit unit 11 is configured to convert the second ac square wave voltage output by the resonant network unit 12 to obtain a second state boost direct current.
In the reverse working state of the bidirectional self-driven DC-DC converter, the second-state direct current at the low-voltage end 15 is converted into second-state alternating current under the processing of the low-voltage side bridge circuit unit 14; under the boosting process of the transformer unit 13, boosting the second state alternating current output by the low-voltage side bridge circuit unit 14 to obtain second state boosted alternating current; under the resonance of the resonance network unit 12, the boost alternating current in the second state is resonated to obtain a second alternating square wave voltage; and under the processing of the high-voltage side full-bridge circuit unit 11, converting the second alternating-current square wave voltage to obtain a second state boosted direct current. The low-voltage side bridge circuit unit 14 can be regarded as an inverter part of the bidirectional self-driven DC-DC converter, and is driven by the DSP unit 20 sending out a PWM signal; the high-side full bridge circuit unit 11 can be regarded as a rectifying part of the bidirectional self-driven DC-DC converter, and operates in a self-driven mode.
Specifically, as shown in fig. 3 and 4, the high-side full-bridge circuit unit 11 includes 4 switching tubes, which are respectively denoted as a first switching tube S1, a second switching tube S2, a third switching tube S3, and a fourth switching tube S4; the first switching tube S1 is connected to the first high-voltage self-driving circuit unit 11a1, the second switching tube S2 is connected to the second high-voltage self-driving circuit unit 11a2, the third switching tube S3 is connected to the third high-voltage self-driving circuit unit 11a3, and the fourth switching tube S4 is connected to the fourth high-voltage self-driving circuit unit 11a 4.
In the forward working state of the bidirectional self-driven DC-DC converter, a full-bridge circuit (which may be regarded as an inverter part) is formed by the first switch tube S1, the second switch tube S2, the third switch tube S3, and the fourth switch tube S4 in the high-voltage full-bridge circuit unit 11, and each switch tube in the high-voltage full-bridge circuit unit 11 is connected to a high-voltage self-driven circuit unit. In the reverse operation state of the bidirectional self-driven DC-DC converter, a rectifying circuit is formed by the first switch tube S1, the second switch tube S2, the third switch tube S3 and the fourth switch tube S4 in the high-side full bridge circuit unit 11 in the self-driven mode. More specifically, the first switch tube S1, the second switch tube S2, the third switch tube S3 and the fourth switch tube S4 are all MOS field effect transistors.
Specifically, as shown in fig. 3 and 4, the low-voltage side bridge circuit unit 14 includes 2 switching tubes, which are respectively denoted as a fifth switching tube S5 and a sixth switching tube S6; the fifth switching tube S5 is connected to the first low-voltage self-driving circuit unit 14a1, and the sixth switching tube S6 is connected to the second low-voltage self-driving circuit unit 14a 2.
In the forward working state of the bidirectional self-driven DC-DC converter, a rectifying circuit is formed by the fifth switching tube S5 and the sixth switching tube S6, each switching tube in the low-voltage side bridge circuit unit 14 is connected to a low-voltage side self-driven circuit unit, and the fifth switching tube S5 and the sixth switching tube S6 form the rectifying circuit in the self-driven mode. In the reverse operation state of the bidirectional self-driven DC-DC converter, an inverter circuit is formed by the fifth switch tube S5 and the sixth switch S6 in the low-side bridge circuit unit 14. More specifically, the fifth switch tube S5 and the sixth switch tube S6 are both MOS field effect tubes.
Specifically, as shown in fig. 4 and 5, the first low-side self-driving circuit unit 14a1 includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, a seventh switch Q6, an eighth switch Q7, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a first resistor R1, and a second resistor R2;
one end of the first resistor R1 is connected to a first direct current voltage V _ bias, and the other end of the first resistor R1 is connected to the base and collector of the first triode Q1;
the emitter of the first triode Q1 is connected with the anode of the first diode D1;
the collector of the second triode Q2 is connected to the first direct current voltage V _ bias, the emitter of the second triode Q2 is connected to the emitter of the third triode Q3, the base of the second triode Q2 is connected to the base of the third triode Q3, and the base of the second triode Q2 is connected to the emitter of the fourth triode Q4;
the base of the third triode Q3 is connected with the emitter of the fourth triode Q4, and the base of the third triode Q3 is also connected with the anode of the second diode D2;
the collector of the fourth triode Q4 is connected to the first direct current voltage V _ bias, the emitter of the fourth triode Q4 is further connected to the anode of the second diode D2, the base of the fourth triode Q4 is connected to the first direct current voltage V _ bias through the second resistor R2, and the base of the fourth triode Q4 is further connected to the cathode of the second diode D2;
a base electrode of the fifth triode Q5 is connected to a base electrode of the first triode Q1, a base electrode of the fifth triode Q5 is further connected to an anode of the third diode D3, a base electrode of the fifth triode Q5 is further connected to a drain electrode of the seventh switching tube Q6, a collector electrode of the fifth triode Q5 is connected to a cathode of the third diode D3, a collector electrode of the fifth triode Q5 is further connected to a base electrode of the fourth triode Q4, a collector electrode of the fifth triode Q5 is further connected to a drain electrode of the eighth switching tube Q7, and an emitter electrode of the fifth triode Q5 is connected to an anode of the fourth diode D4;
the source of the seventh switch Q6 is connected to the collector of the third transistor Q3, and the source of the seventh switch Q6 is also connected to the cathode of the fourth diode D4;
the source electrode of the eighth switch tube Q7 is connected with the source electrode of the seventh switch tube Q6.
Here, the specific circuits of the first low voltage side self-driving circuit unit 14a1 connected to the fifth switching tube S5 are described in detail by taking only the first low voltage side self-driving circuit unit 14a1 as an example, the first high voltage side self-driving circuit unit 11a1 connected to the first switching tube S1, the second high voltage side self-driving circuit unit 11a2 connected to the second switching tube S4, the third high voltage side self-driving circuit unit 11a3 connected to the third switching tube S3, the fourth high voltage side self-driving circuit unit 11a3 connected to the fourth switching tube S1, and the second low voltage side self-driving circuit unit 14a2 connected to the sixth switching tube S6 are identical to the first low voltage side self-driving circuit unit 14a1, and the specific connection method thereof may also refer to the specific circuits of the first low voltage side self-driving circuit unit 14a1 as shown in fig. 4. By using the self-driving circuit, the rectifying part and the inverting part drive the switching tube by controlling the self-driving circuit, so that the driving circuit is simplified; and the self-driving circuit is built by adopting independent circuit components, and a special synchronous rectification chip is not used, so that the device cost is saved.
Specifically, as shown in fig. 3, 4, 6, and 8, the high-side full-bridge circuit unit 11 includes, among the first switch transistor S1, the second switch transistor S2, the third switch transistor S3, and the fourth switch transistor S4:
one end of the first switch tube S1 is connected to the high voltage terminal 10, and the other end of the first switch tube S1 is connected to one end of the second switch tube S2;
the other end of the second switch tube S1 is connected to the high voltage terminal 10; the first switch tube S1 and the second switch tube S2 are connected in series to form a first bridge arm, and the middle point of the first bridge arm is a first network point A;
one end of the third switch tube S3 is connected to the high voltage terminal 10, and the other end of the third switch tube S3 is connected to one end of the fourth switch tube S4;
the other end of the fourth switching tube S4 is connected to the high voltage terminal 10; the third switching tube S3 and the fourth switching tube S4 are connected in series to form a second bridge arm, and the middle point of the second bridge arm is a second network point B.
When the bidirectional self-driven DC-DC converter is in a forward working state, the DSP unit 20 sends a PWM signal (PWM signal, i.e., pulse width modulation signal) to the primary side driving chip U1, and the primary side driving chip U1 outputs corresponding high-voltage side driving signals to the first high-voltage side self-driving circuit unit 11a1, the second high-voltage side self-driving circuit unit 11a2, the third high-voltage side self-driving circuit unit 11a3, and the fourth high-voltage side self-driving circuit unit 11a 4. Specifically, the primary side driving chip U1 outputs a first high-voltage side driving signal Vg1 to the first high-voltage side self-driving circuit unit 11a1, the primary side driving chip U1 outputs a second high-voltage side driving signal Vg2 to the second high-voltage side self-driving circuit unit 11a2, the primary side driving chip U1 outputs a third high-voltage side driving signal Vg3 to the third high-voltage side self-driving circuit unit 11a3, and the primary side driving chip U1 outputs a fourth high-voltage side driving signal Vg4 to the fourth high-voltage side self-driving circuit unit 11a 4. The first high-voltage side driving signal Vg1 drives the first high-voltage side self-driving circuit unit 11a1 to generate a first high-voltage side driving voltage signal Vgs1, the second high-voltage side driving signal Vg2 drives the second high-voltage side self-driving circuit unit 11a2 to generate a second high-voltage side driving voltage signal Vgs2, the third high-voltage side driving signal Vg3 drives the third high-voltage side self-driving circuit unit 11a3 to generate a third high-voltage side driving voltage signal Vgs3, and the fourth high-voltage side driving signal Vg4 drives the fourth high-voltage side self-driving circuit unit 11a4 to generate a fourth high-voltage side driving voltage signal Vgs 4. Where Vgs1 and Vgs2 are 50% duty cycle complementary drive voltage signals (ignoring dead time), Vgs3 and Vgs4 are also 50% duty cycle complementary drive voltage signals (ignoring dead time).
More specifically, as shown in fig. 4, 6, and 8, the first high-voltage side self-driving circuit unit 11a1 and the third high-voltage side self-driving circuit unit 11a3 are connected through a first synchronous digital signal isolator U3; the second high-voltage side self-driving circuit unit 11a2 and the fourth high-voltage side self-driving circuit unit 11a4 are connected through a second SDH isolator (the second SDH isolator is not shown in FIGS. 4, 6 and 8, and its specific wiring method can refer to the first SDH isolator U3). More specifically, the model of the DSP unit 20 IS TMS320F28035PNT, the model of the primary side driving chip U1 IS SI8235BB-D-IS of SILICON, the model of the secondary side driving chip U2 IS SI8235AB-D-IM, and the model of the first synchronous digital signal isolator U3 IS ISO7221AQDRQ1 (manufactured by Texas instruments). As shown in fig. 4, the synchronous isolation signal of the first high-side driving voltage signal Vgs1 is Vgs1 'and the synchronous isolation signal of the third high-side driving voltage signal Vgs3 is Vgs 3'.
When the bidirectional self-driven DC-DC converter is in a reverse operation state, the DSP unit 20 controls the output voltage of the primary side driving chip U1 to be always low level, so that the first high-voltage side driving signal Vg1, the second high-voltage side driving signal Vg2, the third high-voltage side driving signal Vg3, and the fourth high-voltage side driving signal Vg4 are always low level, the first high-voltage side self driving circuit unit 11a1, the second high-voltage side self driving circuit unit 11a2, the third high-voltage side self driving circuit unit 11a3, and the fourth high-voltage side self driving circuit unit 11a4 are driven to generate a first high-voltage side driving voltage signal Vgs1, a second high-voltage side driving voltage signal Vgs2, a third high-voltage side driving voltage signal Vg3, and a fourth high-voltage side driving voltage signal Vgs4, respectively, and the first switching tube S1, the second switching tube S2, the third switching tube S3, and the fourth switching tube S4 are controlled to be turned on and turned off, the first to fourth switching tubes S1 to S4 on the primary side operate in the self-driving mode at this time.
When the first to fourth switching tubes S1 to S4 operate in the self-driving mode, the first high-voltage side driving voltage signal Vgs1 is interlocked by controlling the first high-voltage side self-driving circuit unit 11a1, and the third high-voltage side driving voltage signal Vgs3 is interlocked by controlling the third high-voltage side self-driving circuit unit 11a3, so that the first high-voltage side driving voltage signal Vgs1 and the third high-voltage side driving voltage signal Vgs3 do not occur as high-level signals at the same time. The second high-voltage side driving voltage signal Vgs2 forms an interlock by controlling the second high-voltage side self driving circuit unit 11a2 while the fourth high-voltage side driving voltage signal Vgs4 forms an interlock by controlling the fourth high-voltage side self driving circuit unit 11a4, and the second high-voltage side driving voltage signal Vgs2 and the fourth high-voltage side driving voltage signal Vgs4 do not occur to be high-level signals at the same time. When the first switching tube S1 to the fourth switching tube S4 on the primary side operate in the self-driving mode, the switching tubes of the upper and lower arms of the first arm in the high-voltage side full-bridge circuit unit 11 are effectively prevented from being shared, and the switching tubes of the upper and lower arms of the second arm are also prevented from being shared.
Specifically, as shown in fig. 3, 4, 6, and 8, the resonant network element 12 includes a first inductance Lr, a second inductance Lm1, a third inductance Lm, and a first capacitance Cr;
one end of the first capacitor Cr is connected to the second network point B, and the other end of the first capacitor Cr is connected to the primary side of the transformer unit 13;
one end of the first inductor Lr is connected to the first network point a, one end of the first inductor Lr is further connected to one end of the second inductor Lm1, the other end of the first inductor Lr is connected to the primary side of the transformer unit 13, and the other end of the first inductor Lr is further connected to one end of the third inductor Lm;
one end of the second inductor Lm1 is connected to the first network point a, the other end of the second inductor Lm1 is connected to the second network point B, and the other end of the second inductor Lm1 is further connected to one end of the first capacitor Cr;
one end of the third inductor Lm is connected to the primary side of the transformer unit 13, the other end of the third inductor Lm is connected to the primary side of the transformer unit 13, and the other end of the third inductor Lm is further connected to the other end of the first capacitor Cr.
The excitation inductance of the resonant network unit 12 is a third inductance Lm, the resonant inductance is a first inductance Lr, the resonant capacitance is a first capacitance Cr, and the auxiliary inductance is a second inductance Lm 1. The alternating current can be resonated by the resonant network unit 12 to obtain an alternating square wave voltage.
Specifically, as shown in fig. 3, 4, 6, and 8, the secondary side of the transformer unit 13 includes 3 taps, which are a secondary side first tap, a secondary side second tap, and a secondary side third tap (the secondary side first tap, the secondary side second tap, and the secondary side third tap are not identified in the transformer T1 in fig. 4, 6, and 8, and the secondary side first tap, the secondary side second tap, and the secondary side third tap are sequentially distributed from top to bottom in the secondary side of the transformer unit 13 in the above-mentioned figure); wherein the secondary side second connector is connected with one end of the low-voltage end 15.
The transformer unit 13 may also be denoted as a transformer T1, the primary-secondary turn ratio of the transformer T1 is n:1, and the transformer unit 11 can effectively boost or reduce the voltage of the alternating current.
Specifically, as shown in fig. 3, 4, 6, and 8, the fifth switching transistor S5 and the sixth switching transistor S6 included in the low-side bridge circuit unit 14 are MOS transistors, and are respectively denoted as a fifth MOS transistor and a sixth MOS transistor;
the drain of the fifth MOS transistor is connected to the secondary first terminal of the transformer unit 11, the drain of the fifth MOS transistor is further connected to the negative electrode of the first diode D1, the gate of the fifth MOS transistor is connected to the emitter of the second transistor Q2, the gate of the fifth MOS transistor is further connected to the emitter of the third transistor Q3, the source of the fifth MOS transistor is connected to the source of the sixth MOS transistor, the source of the fifth MOS transistor is further connected to the collector of the third transistor Q3, the source of the fifth MOS transistor is further connected to the source of the seventh switch Q6, the source of the fifth MOS transistor is further connected to the negative electrode of the fourth diode D4, and the source of the fifth MOS transistor is further connected to the source of the eighth switch Q7;
the drain of the sixth MOS transistor is connected to the secondary side third terminal of the transformer unit 13, the drain of the sixth MOS transistor is further connected to the second low-voltage side self-driving circuit unit 14a2, the source of the sixth MOS transistor is connected to the second low-voltage side self-driving circuit unit 14a2, the source of the sixth MOS transistor is further grounded, the source of the sixth MOS transistor is further connected to the other end of the low-voltage terminal 15, and the gate of the sixth MOS transistor is connected to the second low-voltage side self-driving circuit unit 14a 2.
When the bidirectional self-driven DC-DC converter is in a reverse operation state, the DSP unit 20 sends a PWM signal (i.e., a PWM signal) to the secondary driving chip U2, and the secondary driving chip U2 outputs corresponding low-voltage-side driving signals to the first low-voltage-side self driving circuit unit 14a1 and the second low-voltage-side self driving circuit unit 14a 2. Specifically, the secondary driving chip U2 outputs a first low-voltage driving signal Vg5 to the first low-voltage self-driving circuit unit 14a1, and the secondary driving chip U2 outputs a second low-voltage driving signal Vg6 to the second low-voltage self-driving circuit unit 14a 2. The first low-side drive signal Vg5 drives the first low-side self-drive circuit unit 14a1 to generate a first low-side drive voltage signal Vgs5, and the second low-side drive signal Vg6 drives the second low-side self-drive circuit unit 14a2 to generate a second low-side drive voltage signal Vgs6, where Vgs5 and Vgs6 are complementary drive voltage signals at 50% duty cycle (ignoring dead time).
When the bidirectional self-driven DC-DC converter is in the forward operation state, the DSP unit 20 controls the output voltage of the secondary side driving chip U2 to be always at the low level, so that the first low-voltage side driving signal Vg5 drives the first low-voltage side self-driving circuit unit 14a1 to generate the first low-voltage side driving voltage signal Vgs5, and the second low-voltage side driving signal Vg6 drives the second low-voltage side self-driving circuit unit 14a2 to generate the second low-voltage side driving voltage signal Vgs 6. The first low-voltage side driving voltage signal Vgs5 and the second low-voltage side driving voltage signal Vgs6 control the fifth switching tube S5 and the sixth switching tube S6 to be turned on and off, respectively, and then the fifth switching tube S5 and the sixth switching tube S6 on the secondary side operate in the self-driving mode at this time.
When the fifth switching tube S5 and the sixth switching tube S6 operate in the self-driving mode, the first low-voltage side driving voltage signal Vgs5 forms an interlock by controlling the first low-voltage side self-driving circuit unit 14a1, and the second low-voltage side driving voltage signal Vgs6 forms an interlock by controlling the second low-voltage side self-driving circuit unit 14a2, so that the first low-voltage side driving voltage signal Vgs5 and the second low-voltage side driving voltage signal Vgs6 do not occur while being high-level signals. When the secondary side fifth switch tube S5 and the secondary side sixth switch tube S6 operate in the self-driving mode, the common phenomenon of the fifth switch tube S5 and the sixth switch tube S6 in the low-side bridge circuit unit 14 is effectively avoided.
In order to better understand the specific operation of the bidirectional self-driven DC-DC converter, the following description is made in conjunction with fig. 3 to 9 c.
Please refer to fig. 6 for the operation process of the forward operation state of the bidirectional self-driven DC-DC converter, and fig. 7a to fig. 7c for the timing diagrams of the forward operation state of the bidirectional self-driven DC-DC converter.
When the switching frequency fs of the bidirectional self-driven DC-DC converter is less than the resonant frequency fr, the timing diagram is as shown in FIG. 7 a:
1) in the operating mode 1, the time interval is [ t0, t1 ]]At time t0, the DSP unit 20 sends out the PWM signal Vg1 to the first high-voltage-side self-driving circuit unit 11a1 corresponding to the first switch tube S1, and sends out the PWM signal Vg4 to the fourth high-voltage-side self-driving circuit unit 11a4 corresponding to the fourth switch tube S4. The first high-voltage side self-driving circuit unit 11a1 and the fourth high-voltage side self-driving circuit unit 11a4 start to operate, and generate driving voltages Vgs1 and Vgs4 respectively to turn on the first switching tube S1 and the fourth switching tube S4, at which time the resonant current irAnd auxiliary inductor current iLm1The sum freewheels through the body diodes of the first switching tube S1 and the fourth switching tube S4, the voltages across the first switching tube S1 and the fourth switching tube S4 are clamped to zero, respectively, and the first switching tube S1 and the fourth switching tube S4 achieve zero-voltage turn-on (ZVS). At this time, the input voltage V1 is applied to two points, i.e. a first network point A and a second network point Br、iLm、iLm1Begins to increase while the current iS6When the current flows through the sixth switching tube S6, the self-driving circuit corresponding to the sixth switching tube S6, i.e., the second low-voltage side self-driving circuit unit 14a2, starts to operate, and the generated driving voltage Vgs6 turns on the sixth switching tube S6, so that the sixth switching tube S6 turns on a Zero Current (ZCS). The voltage at C, D two points on the secondary side of the transformer unit 11 is clamped at 2 times V2, irAnd iLm1The sum of the positive and negative zero-crossings flows through the first switch tube S1 and the fourth switch tube S4.
2) In the operating mode 2, the time interval is [ t1, t2 ]]At time t1, resonant current irAnd an excitation current iLmEqual to the current i flowing through the sixth switch tube S6S6When the voltage drops to zero, the self-driving circuit of the sixth switching tube S6 stops operating from the second low-voltage side self-driving circuit unit 14a2, no Vgs6 is generated, the sixth switching tube S6 is turned off, and the sixth switching tube S6 realizes zero current turn-off (ZCS). At this time, series harmonics of Lr, Lm and Cr occurVibration irSlowly rises.
3) In the operating mode 3, the time interval is [ t2, t3 ]]At time t2, the DSP unit 20 stops sending PWM signals Vg1 and Vg4, the first high-voltage side self-driving circuit unit 11a1 and the fourth high-voltage side self-driving circuit unit 11a4 stop operating, no driving voltages Vgs1 and Vgs4 are generated, the first switch tube S1 and the fourth switch tube S4 are turned off, and the current irAnd iLm1The sum charges the junction current of the first switch tube S1 and the fourth switch tube S4 to V1, and discharges the junction capacitance of the second switch tube S2 and the third switch tube S3 to zero. After the process is finished, the voltages of the two points of the first network point A and the second network point B are both-V1.
4) In the operating mode 4, the time interval is [ t3, t4 ]]At time t3, the discharge of the junction capacitor between the second switch tube S2 and the third switch tube S3 is completed, and the current irAnd iLm1The current of the second switching tube S2 and the body diode of the third switching tube S3 follow current, and the body diode of the fifth switching tube S5 is turned onS5Starting to increase from zero, the self-driving circuit of the fifth switch tube S5, the first low-voltage side self-driving circuit unit 14a1, starts to operate, and generates the driving voltage Vgs5 to turn on the fifth switch tube S5. The energy transmission process of the latter half cycle is started from the time t4, and the work project of the latter half cycle corresponds to the above 4 work projects, and is not described in detail.
When the switching frequency fs of the bidirectional self-driven DC-DC converter is equal to the resonant frequency fr in the forward operation state, the timing diagram is shown in fig. 7b, and the specific 4 operation modes are the same as those when the switching frequency fs of the bidirectional self-driven DC-DC converter is less than the resonant frequency fr, and the detailed contents thereof will not be described again. Similarly, when the switching frequency fs of the bidirectional self-driven DC-DC converter in the forward operation state is greater than the resonant frequency fr, the timing diagram thereof is shown in fig. 7c, and the specific 4 operation modes are the same as those when the switching frequency fs of the bidirectional self-driven DC-DC converter is less than the resonant frequency fr, and the specific contents thereof will not be described in detail herein.
Please refer to fig. 8 for the operation process of the reverse operation state of the bidirectional self-driven DC-DC converter, and refer to fig. 9a to fig. 9c for the timing chart of the reverse operation state of the bidirectional self-driven DC-DC converter.
When the switching frequency fs of the bidirectional self-driven DC-DC converter is less than the resonant frequency fr, the timing diagram is as shown in FIG. 9 a:
11) in the operating mode 1, the time interval is [ t0, t1 ]]At time t0, current iS6The voltage across the sixth switching tube S6 is clamped to zero by the body diode of the sixth switching tube S6, and at this time, the DSP unit 20 sends a PWM signal Vg6 to the self-driving circuit of the sixth switching tube S6 (i.e., the second low-voltage side self-driving circuit unit 14a2), and the second low-voltage side self-driving circuit unit 14a2 starts to operate to generate a driving voltage Vgs6, so that the sixth switching tube S6 is turned on, and the sixth switching tube S6 realizes zero-voltage turn-on (ZVS). At this time, the voltage at C, D point on the secondary side of the transformer unit 11 is clamped at 2 times V2, the current ir、iLm1And iLm2Starting to increase from the negative direction, the resonant current irAnd iLm1The first high-voltage self-driving circuit unit 11a1 and the fourth high-voltage self-driving circuit unit 11a4 start to operate through the first switching tube S1 and the fourth switching tube S4, the generated driving voltages Vgs1 and Vgs4 turn on the first switching tube S1 and the fourth switching tube S4, respectively, and the first switching tube S1 and the fourth switching tube S4 are turned on by Zero Current (ZCS). The voltage at the first and second network points a and B is clamped at the input voltage V1.
12) In the operating mode 2, the time interval is [ t1, t2 ]]At time t1, resonant current irAnd an excitation current iLm1Equal to the current i flowing through the first switch tube S1S1And a current i flowing through the fourth switching tube S4S4Dropping to zero, the first high-voltage side self-driving circuit unit 11a1 and the fourth high-voltage side self-driving circuit unit 11a4 start to stop operating, the driving voltages Vgs1 and Vgs4 are not generated, the first switching tube S1 and the fourth switching tube are turned off, and S1 and S4 are zero current turn-off (ZCS). At this time, Lr, Lm1 and Cr are in series resonance, irSlowly rises.
13) In the operating mode 3, the time interval is [ t2, t3 ]]At time t2, the DSP unit 20 stops sending the PWM signal Vg6, and the self-driving circuit of the sixth switch tube S6 (i.e. the second low-voltage side)The self-driving circuit unit 14a2) stops working, the sixth switching tube S6 is turned off without generating the driving voltage Vgs6, and the current iS6The junction current of the sixth switching tube S6 is charged to 2 times V2, and the junction capacitance of the fifth switching tube S5 is discharged to zero. After this process is over, the voltage at C, D is 2 times-V2.
14) In the operating mode 4, the time interval is [ t3, t4 ]]At time t3, the discharge of the junction capacitor of the fifth switch tube S5 is completed, and the current iS5Freewheeling is achieved through the body diode of the fifth switching tube S5, the body diodes of the second switching tube S2 and the third switching tube S3 are turned on, iS2And iS3Starting from zero, the self-driving circuits of the second switch tube S2 and the third switch tube S3 start to operate (i.e., the second high-voltage side self-driving circuit unit 11a2 and the third high-voltage side self-driving circuit unit 11a3 start to operate), and generate driving voltages Vgs2 and Vgs3 to turn on the second switch tube S2 and the third switch tube S3, respectively. The energy transmission process of the latter half cycle is started from the time t4, and the work project of the latter half cycle corresponds to the above 4 work projects, and is not described in detail.
When the switching frequency fs of the bidirectional self-driven DC-DC converter is equal to the resonant frequency fr in the reverse operation state, the timing diagram is shown in fig. 9b, and the specific 4 operation modes are the same as those when the switching frequency fs of the bidirectional self-driven DC-DC converter is less than the resonant frequency fr, and the detailed contents thereof will not be described again. Similarly, when the switching frequency fs of the bidirectional self-driven DC-DC converter in the reverse operation state is greater than the resonant frequency fr, the timing diagram is shown in fig. 9c, and the specific 4 operation modes are the same as those when the switching frequency fs of the bidirectional self-driven DC-DC converter is less than the resonant frequency fr, and the specific contents thereof will not be described in detail herein.
The bidirectional self-driven DC-DC converter solves the problem of reverse current flow of the switching tubes of the rectifying part when the switching frequency fs is less than the resonance frequency fr, improves the reliability of the converter, simultaneously realizes synchronous rectification control of the switching tubes of the rectifying part and ZCS soft switching of the switching tubes of the rectifying part, and improves the conversion efficiency of the converter.
It can be seen that, in this embodiment, the switching tubes included in the high-voltage side full bridge circuit unit are all connected to the high-voltage side self-driving circuit unit, and the switching tubes included in the low-voltage side bridge circuit unit are all connected to the low-voltage side self-driving circuit unit, and no matter in a forward working state or a reverse working state, the switching tubes of the corresponding rectifying portions all adopt a self-driving mode, and the switching tubes of the corresponding inverting portions adopt other driving modes, so that a software control strategy of a bidirectional LLC converter synchronous rectification driving technology is simplified, a proprietary synchronous rectification chip is not required to be used, and a circuit structure of the self-driving is simplified.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A bidirectional self-driven DC-DC converter is characterized by comprising a high-voltage side full-bridge circuit unit, a resonant network unit, a transformer unit and a low-voltage side bridge circuit unit; the switching tubes included in the high-voltage side full-bridge circuit unit are connected with the high-voltage side self-driving circuit unit, and the switching tubes included in the low-voltage side full-bridge circuit unit are connected with the low-voltage side self-driving circuit unit;
one end of the high-voltage side full-bridge circuit unit is connected with a high-voltage end, and the other end of the high-voltage side full-bridge circuit unit is connected with one end of the resonant network unit;
the other end of the resonant network unit is connected with the primary side of the transformer unit;
the secondary side of the transformer unit is connected with one end of the low-voltage side bridge type circuit unit;
the other end of the low-voltage side bridge circuit unit is connected with a low-voltage end;
in a forward working state of the bidirectional self-driven DC-DC converter, when the high-voltage side full-bridge circuit unit receives a driving signal of the high-voltage side self-driven circuit unit, the high-voltage side full-bridge circuit unit converts the first-state direct current at the high-voltage end sequentially through the high-voltage side full-bridge circuit unit, the resonant network unit, the transformer unit and the low-voltage side bridge circuit unit to obtain a first-state step-down direct current output by the low-voltage end;
in a reverse working state of the bidirectional self-driven DC-DC converter, when the low-voltage side bridge circuit unit receives a driving signal of the low-voltage side self-driven circuit unit, the low-voltage side bridge circuit unit converts the second-state direct current of the low-voltage end sequentially through the low-voltage side bridge circuit unit, the transformer unit, the resonant network unit and the high-voltage side full bridge circuit unit to obtain a second-state boosting direct current output by the high-voltage end;
the low-voltage side bridge circuit unit comprises 2 switching tubes which are respectively marked as a fifth switching tube and a sixth switching tube; the fifth switching tube is connected with the first low-voltage side self-driving circuit unit, and the sixth switching tube is connected with the second low-voltage side self-driving circuit unit;
the first low-voltage side self-driving circuit unit comprises a first triode, a second triode, a third triode, a fourth triode, a fifth triode, a seventh switching tube, an eighth switching tube, a first diode, a second diode, a third diode, a fourth diode, a first resistor and a second resistor;
one end of the first resistor is connected with a first direct-current voltage, and the other end of the first resistor is connected with a base electrode and a collector electrode of the first triode;
an emitting electrode of the first triode is connected with the anode of the first diode;
a collector of the second triode is connected with the first direct-current voltage, an emitter of the second triode is connected with an emitter of the third triode, a base of the second triode is connected with a base of the third triode, and the base of the second triode is also connected with an emitter of the fourth triode;
the base electrode of the third triode is connected with the emitter electrode of the fourth triode, and the base electrode of the third triode is also connected with the anode of the second diode;
a collector of the fourth triode is connected with the first direct-current voltage, an emitter of the fourth triode is also connected with the anode of the second diode, a base of the fourth triode is connected with the first direct-current voltage through the second resistor, and a base of the fourth triode is also connected with the cathode of the second diode;
the base electrode of the fifth triode is connected with the base electrode of the first triode, the base electrode of the fifth triode is further connected with the anode of the third diode, the base electrode of the fifth triode is further connected with the drain electrode of the seventh switching tube, the collector electrode of the fifth triode is connected with the cathode of the third diode, the collector electrode of the fifth triode is further connected with the base electrode of the fourth triode, the collector electrode of the fifth triode is further connected with the drain electrode of the eighth switching tube, and the emitter electrode of the fifth triode is connected with the anode of the fourth diode;
the source electrode of the seventh switching tube is connected with the collector electrode of the third triode, and the source electrode of the seventh switching tube is also connected with the cathode of the fourth diode;
and the source electrode of the eighth switching tube is connected with the source electrode of the seventh switching tube.
2. A bi-directional self-driven DC-DC converter according to claim 1, wherein in a forward operating state of the bi-directional self-driven DC-DC converter:
the high-voltage side full-bridge circuit unit is used for receiving a driving signal of the high-voltage side self-driving circuit unit and converting the first-state direct current at the high-voltage end into first-state alternating current;
the resonance network unit is used for resonating the first state alternating current output by the high-voltage side full-bridge circuit unit to obtain a first alternating square wave voltage;
the transformer unit is used for reducing the first alternating-current square wave voltage output by the resonance network unit to obtain a first-state reduced-voltage alternating current;
the low-voltage side bridge circuit unit is used for converting the first-state step-down alternating current output by the transformer unit to obtain first-state step-down direct current.
3. A bi-directional self-driven DC-DC converter according to claim 1, characterized in that in a reverse operating state of the bi-directional self-driven DC-DC converter:
the low-voltage side bridge circuit unit is used for receiving a driving signal of the low-voltage side self-driving circuit unit and converting the second-state direct current at the low-voltage end into second-state alternating current;
the transformer unit is used for boosting the second-state alternating current output by the low-voltage side bridge circuit unit to obtain second-state boosted alternating current;
the resonance network unit is used for resonating the second-state boosting alternating current output by the transformer unit to obtain a second alternating square wave voltage;
and the high-voltage side full-bridge circuit unit is used for converting the second alternating-current square wave voltage output by the resonant network unit to obtain the boosting direct current in the second state.
4. A bidirectional self-driven DC-DC converter according to any one of claims 1 to 3, characterized in that the high-side full-bridge circuit unit comprises 4 switching tubes, which are respectively marked as a first switching tube, a second switching tube, a third switching tube and a fourth switching tube; the first switch tube is connected with the first high-voltage side self-driving circuit unit, the second switch tube is connected with the second high-voltage side self-driving circuit unit, the third switch tube is connected with the third high-voltage side self-driving circuit unit, and the fourth switch tube is connected with the fourth high-voltage side self-driving circuit unit.
5. The bidirectional self-driven DC-DC converter according to claim 1, wherein the high-side full-bridge circuit unit comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein:
one end of the first switch tube is connected with the high-voltage end, and the other end of the first switch tube is connected with one end of the second switch tube;
the other end of the second switch tube is connected with the high-voltage end; the first switching tube and the second switching tube are connected in series to form a first bridge arm, and the middle point of the first bridge arm is a first network point;
one end of the third switching tube is connected with the high-voltage end, and the other end of the third switching tube is connected with one end of the fourth switching tube;
the other end of the fourth switching tube is connected with the high-voltage end; the third switching tube and the fourth switching tube are connected in series to form a second bridge arm, and the middle point of the second bridge arm is a second network point.
6. A bidirectional self-driven DC-DC converter according to claim 5, characterized in that the resonant network unit comprises a first inductance, a second inductance, a third inductance, and a first capacitance;
one end of the first capacitor is connected with the second network point, and the other end of the first capacitor is connected with the primary side of the transformer unit;
one end of the first inductor is connected with the first network point, one end of the first inductor is also connected with one end of the second inductor, the other end of the first inductor is connected with the primary side of the transformer unit, and the other end of the first inductor is also connected with one end of the third inductor;
one end of the second inductor is connected with the first network point, the other end of the second inductor is connected with the second network point, and the other end of the second inductor is also connected with one end of the first capacitor;
one end of the third inductor is connected with the primary side of the transformer unit, the other end of the third inductor is connected with the primary side of the transformer unit, and the other end of the third inductor is further connected with the other end of the first capacitor.
7. A bidirectional self-driven DC-DC converter according to claim 6, characterized in that the secondary side of the transformer unit comprises 3 taps, a secondary side first tap, a secondary side second tap, a secondary side third tap, respectively; wherein the secondary side second joint is connected with one end of the low-voltage end.
8. The bidirectional self-driven DC-DC converter according to claim 7, wherein the fifth switching tube and the sixth switching tube included in the low-voltage side bridge circuit unit are both MOS tubes, which are respectively denoted as a fifth MOS tube and a sixth MOS tube;
the drain of the fifth MOS transistor is connected to the first secondary terminal of the transformer unit, the drain of the fifth MOS transistor is further connected to the negative electrode of the first diode, the gate of the fifth MOS transistor is connected to the emitter of the second triode, the gate of the fifth MOS transistor is further connected to the emitter of the third triode, the source of the fifth MOS transistor is connected to the source of the sixth MOS transistor, the source of the fifth MOS transistor is further connected to the collector of the third triode, the source of the fifth MOS transistor is further connected to the source of the seventh switching transistor, the source of the fifth MOS transistor is further connected to the negative electrode of the fourth diode, and the source of the fifth MOS transistor is further connected to the source of the eighth switching transistor;
the drain electrode of the sixth MOS tube is connected with the third joint of the secondary side of the transformer unit, the drain electrode of the sixth MOS tube is also connected with the second low-voltage side self-driving circuit unit, the source electrode of the sixth MOS tube is also grounded, the source electrode of the sixth MOS tube is also connected with the other end of the low-voltage end, and the grid electrode of the sixth MOS tube is connected with the second low-voltage side self-driving circuit unit.
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| CN102035394A (en) * | 2010-12-20 | 2011-04-27 | 北京新雷能科技股份有限公司 | Forward topology synchronous rectification driver circuit |
| CN105006974A (en) * | 2015-07-30 | 2015-10-28 | 广州金升阳科技有限公司 | Synchronous rectification control method, control device and switch power supply |
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| US7203041B2 (en) * | 2004-04-30 | 2007-04-10 | Power-One, Inc | Primary side turn-off of self-driven synchronous rectifiers |
| US9660544B1 (en) * | 2014-08-08 | 2017-05-23 | Flextronics Ap, Llc | Self-driven synchronous rectifier circuit |
| CN107659127B (en) * | 2016-07-25 | 2021-05-28 | 中兴通讯股份有限公司 | Control method and device of synchronous rectification self-driving circuit |
| CN209930165U (en) * | 2019-01-30 | 2020-01-10 | 西安福华力能电源有限公司 | Synchronous rectifying device using driving winding |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102035394A (en) * | 2010-12-20 | 2011-04-27 | 北京新雷能科技股份有限公司 | Forward topology synchronous rectification driver circuit |
| CN105006974A (en) * | 2015-07-30 | 2015-10-28 | 广州金升阳科技有限公司 | Synchronous rectification control method, control device and switch power supply |
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