CN111669057B - DC boost converter and control method thereof - Google Patents

DC boost converter and control method thereof Download PDF

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Publication number
CN111669057B
CN111669057B CN202010455356.XA CN202010455356A CN111669057B CN 111669057 B CN111669057 B CN 111669057B CN 202010455356 A CN202010455356 A CN 202010455356A CN 111669057 B CN111669057 B CN 111669057B
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diode
phase
bridge
coupling inductance
switching tube
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CN111669057A (en
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曹国恩
王一波
曹睿
王哲
王环
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Institute of Electrical Engineering of CAS
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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
    • 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
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

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

Abstract

The invention belongs to the technical field of direct current converters, and particularly relates to a direct current boost converter and a control method thereof, aiming at solving the problems of large loss and narrow working range of the traditional direct current boost converter. The invention comprises the following steps: input power interface, coupling inductance unit and half-bridge unitThe device comprises a unit, a bus supporting capacitor, a pre-charging diode, an isolation transformer, a rectifying and filtering circuit and a power output interface. Wherein, the input power interface can input a photovoltaic or fuel cell power supply with a wide voltage range; the coupling inductance unit comprises a phase A coupling inductance and a phase B coupling inductance; the half-bridge unit comprises a first bridge arm and a second bridge arm; the rectifying and filtering circuit comprises a diode D1‑D4Capacitor Co. The two booster circuits on the primary side are connected in parallel and complementarily share power loss, the current ripple frequency is twice of the switching frequency of the main switching tube, a transformer with a simple structure can be adopted to provide a high boosting ratio, the switching stress of the converter can be reduced through the resonant soft switch, and the performance of the converter is improved.

Description

DC boost converter and control method thereof
Technical Field
The invention belongs to the technical field of direct current converters, and particularly relates to a direct current boost converter and a control method thereof.
Background
The photovoltaic grid-connected power generation is one of important ways of solar energy utilization, with the development of high-power electronic semiconductor devices, the direct-current transmission cost is gradually reduced, the flexible direct-current transmission technology is rapidly developed, and the photovoltaic direct-current grid-connected power generation has the characteristics of flexibility, reliability, economy and the like of a multi-terminal flexible direct-current system, is more suitable for the fields of distributed power generation, power market and the like, and becomes an important utilization form of future photovoltaic power generation.
The photovoltaic cell has the characteristics of soft output characteristics, low voltage level, large voltage fluctuation range and the like, so that the photovoltaic cell needs to be boosted into stable direct-current high voltage after being subjected to DC/DC power conversion with high voltage gain and wide input voltage range so as to meet the requirements of direct-current grid connection or load.
An isolated boost converter and a control technique thereof have been recently researched as one of key techniques of the power generation system. The traditional isolated full-bridge Boost converter has the advantages of high Boost ratio, wide input range and the like, but an active clamping circuit with high requirements on control sequence is required to be configured to absorb the energy of leakage inductance of the transformer, under the application of high power, the voltage stress of a switching tube in the circuit can be increased by the leakage inductance of the transformer and the parasitic inductance of the clamping circuit, and the topology has the problems of complex starting process and the like. The double-inductance half-bridge isolation type Boost converter adopts two half-bridge type Boost converters which are connected in parallel in a staggered mode, reduces the current stress of a switching tube and can reduce input current ripples, but the double-inductance half-bridge isolation type Boost converter works in a hard switching state, has higher voltage stress of a main switching tube, limits the efficiency of the converter due to larger switching loss, and is not suitable for being used in high-power application. The Boost push-pull forward converter combines a Boost push-pull structure with a forward topology, and has the advantages of small number of devices, high utilization rate of a magnetic core, good voltage output characteristic and the like, however, the voltage stress of a switching tube is 2 times of that of a full-bridge circuit, the converter is not suitable for application with higher input voltage, and the problem of direct current magnetic bias can cause overlarge excitation current of a high-frequency transformer and even damage the switching tube.
Disclosure of Invention
In order to solve the above problems in the prior art, that is, the problems of large loss and narrow working range of the conventional dc boost converter, the present invention provides a dc boost converter, which includes an input power interface, a coupling inductor unit, a half-bridge unit, a bus support capacitor, a pre-charge diode, an isolation transformer, a rectifying and filtering circuit, and an output power interface;
the positive electrode of the input power supply interface is connected to the first connecting end T of the coupling inductance unitL1The anode of the pre-charging diode is connected with the cathode of the input power supply interface and the cathode of the half-bridge unit second connecting end B and the cathode of the bus supporting capacitor;
second connection terminal T of the coupling inductance unitL2The first connecting end A is connected to the positive electrode of the bus supporting capacitor, the cathode of the pre-charging diode and the first half-bridge unit; third connection terminal T of the coupling inductance unitL3Is connected to theA third connecting end C of the half-bridge unit and a first input end of the isolation transformer; fourth connection terminal T of the coupling inductance unitL4The fourth connection end D of the half-bridge unit and the second input end of the isolation transformer are connected;
the first output end of the isolation transformer is connected to the first input end of the rectification and filtering circuit, and the second output end of the isolation transformer is connected to the second input end of the rectification and filtering circuit;
the first output end of the rectification and filtering circuit is connected to the anode of the output power interface, and the second output end of the rectification and filtering circuit is connected to the cathode of the output power interface.
In some preferred embodiments, the coupling inductance unit includes a phase-A coupling inductance LaAnd La' B phase coupling inductance LbAnd Lb', A phase continuous flow diode DaAnd B phase continuous flow diode Db；
The A phase coupling inductor LaAnd La' the dotted terminal, B phase coupling inductance LbAnd Lb' the same name ends are connected together to serve as a first connection end T of the coupling inductance unitL1；
The A phase coupling inductor La'the non-homonymous terminal of the' is connected to the A-phase continuous flow diode DaThe B phase coupling inductance Lb'the non-homonymous terminal of the' is connected to the B-phase continuous flow diode DbThe A continuous flow diode DaDiode D continuous with BbAre connected together as a second connection terminal T of the coupled inductive unitL2；
The A phase coupling inductor LaAs a third connection terminal T of the coupling inductance unitL3；
The B phase coupling inductor LbAs a fourth connection terminal T of the coupling inductance unitL4。
In some preferred embodiments, the half-bridge cells comprise a first leg and a second leg;
the first bridge arm comprises an upper pipe S1Lower tube S2；
The second bridge arm comprises an upper pipe S3Lower tube S4；
The switch tube SxParasitic diodes D each comprising a devicesxAnd parasitic capacitance Csx(ii) a Wherein x is 1,2,3, 4;
the upper pipe S1And the upper tube S3Are connected together as a first connection terminal A of the half-bridge unit;
the lower pipe S2And the lower tube S4Are connected together as a second connection terminal B of the half-bridge cell;
the upper pipe S1And the lower tube S2Are connected together as a third connection C of the half-bridge cell;
the upper pipe S3And the lower tube S4Are connected together as a fourth connection D of the half-bridge cell.
In some preferred embodiments, the isolation transformer comprises a primary winding, a secondary winding and a transformer primary leakage inductance Lr；
The primary side leakage inductance L of the transformerrParasitic in the isolation transformer;
the first connecting end and the second connecting end of the primary winding are respectively used as a first input end and a second input end of the isolation transformer;
and the first connecting end and the second connecting end of the secondary winding are respectively used as a first output end and a second output end of the isolation transformer.
In some preferred embodiments, the rectifying and filtering circuit comprises a diode D1Diode D2Diode D3Diode D4And a filter capacitor Co；
The diode D1And the diode D2The cathode of the rectifier and filter circuit is connected with the first input end of the rectifier and filter circuit;
the diode D3And the diode D4The cathode of the rectifier and filter circuit is connected with the second input end of the rectifier and filter circuit;
the diode D1Cathode of (2), diode D3Cathode and filter capacitor CoAre connected together as a first output terminal of the rectifying and filtering circuit;
the diode D2Anode of (2), diode D4Anode and filter capacitor CoAre connected together as a second output of the rectifying and filtering circuit.
In some preferred embodiments, the a-phase coupling inductor and the B-phase coupling inductor are coupled in the same direction.
In some preferred embodiments, the phase A coupling inductance LaAnd La', A phase continuous flow diode DaThe A-phase booster circuit is formed with the first bridge arm;
the B phase coupling inductor LbAnd Lb', B phase continuous flow diode DbAnd the second bridge arm form a B-phase booster circuit.
In another aspect of the present invention, a method for controlling a dc boost converter is provided, where the method includes:
step S10, setting the upper tube S1And a lower pipe S2Are complementary, upper tube S3And a lower pipe S4Are complementary and the upper tube S1And the lower tube S4Are the same, the lower tube S2And an upper pipe S3The duty ratio of (A) is the same; setting a phase shift angle phi between driving signals of a first bridge arm and a second bridge arm;
step S20, realizing S through the energy transfer function of the coupling inductor in the switching process1、S2、S3And S4Soft switching over the entire switching period;
step S30, modulating S at different time points in the switching period1、S2、S3And S4The control of the output voltage is realized by combining the regulation of the duty ratio of the switching tube and the phase shift angle phi of the bridge arm.
The invention has the beneficial effects that:
(1) the direct current boost converter realizes soft switching of all switching devices through the energy transfer function of the coupling inductor, greatly reduces the switching loss of a switching tube, and is beneficial to improving the switching frequency and reducing the system volume and realizing higher energy conversion efficiency.
(2) The direct current boost converter realizes the stable control of output voltage by adjusting the two control degrees of freedom of duty ratio and phase shift angle, overcomes the defect of low efficiency caused by current circulation and improves the efficiency of the converter.
(3) The direct current boost converter can realize wide-range input voltage, realize soft switching of a switching device in a wide voltage range and improve the comprehensive adaptability of the converter by adjusting two control degrees of freedom of the duty ratio and the phase shift angle.
(4) According to the direct-current boost converter, the two boost circuits on the primary side work in a staggered and parallel mode, so that the ripple frequency of input and output current is twice of the switching frequency, the size of an input and output filter can be obviously reduced, and high power density is realized.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of the circuit configuration of the DC boost converter of the present invention;
FIG. 2 is a waveform diagram illustrating the operation of an embodiment of the DC boost converter of the present invention when D is less than or equal to 0.5;
FIG. 3 is a waveform diagram illustrating the operation of one embodiment of the DC boost converter of the present invention when D > 0.5;
FIG. 4 is a schematic diagram of an equivalent circuit configuration of an embodiment of the DC boost converter of the present invention at state 1;
FIG. 5 is a schematic diagram of an equivalent circuit configuration of an embodiment of the DC boost converter of the present invention at State 2;
FIG. 6 is a schematic diagram of an equivalent circuit configuration of the DC boost converter of one embodiment of the present invention at State 3;
fig. 7 is a schematic diagram of an equivalent circuit configuration of the circuit of an embodiment of the dc boost converter of the present invention at state 4.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the related invention are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
The invention provides a direct current boost converter, wherein two boost circuits on the primary side of the converter are connected in parallel and work complementarily, the power loss is shared, and the ripple frequency of input and output current is twice of the switching frequency of a main switching tube. Based on the structural characteristics of the converter, the converter can provide higher boost ratio by adopting an isolation boost transformer with a simpler structure, can effectively reduce the switching stress of the converter through a resonant soft switch, and can effectively improve the performance of the converter.
The converter is not only suitable for the application range of the conventional DC/DC converter, but also suitable for new energy power generation systems such as photovoltaic power generation, fuel cell power generation and the like.
The invention relates to a direct current boost converter, which comprises an input power interface, a coupling inductance unit, a half-bridge unit, a bus support capacitor, a pre-charging diode, an isolation transformer, a rectifying and filtering circuit and an output power interface, wherein the input power interface is connected with the half-bridge unit;
the positive electrode of the input power supply interface is connected to the first connecting end T of the coupling inductance unitL1The anode of the pre-charging diode is connected with the cathode of the input power supply interface and the cathode of the half-bridge unit second connecting end B and the cathode of the bus supporting capacitor;
second connection terminal T of the coupling inductance unitL2A support capacitor connected to the bus barThe anode, the cathode of the pre-charging diode and the first connection end A of the half-bridge unit; third connection terminal T of the coupling inductance unitL3The third connection end C of the half-bridge unit and the first input end of the isolation transformer are connected; fourth connection terminal T of the coupling inductance unitL4The fourth connection end D of the half-bridge unit and the second input end of the isolation transformer are connected;
the first output end of the isolation transformer is connected to the first input end of the rectification and filtering circuit, and the second output end of the isolation transformer is connected to the second input end of the rectification and filtering circuit;
the first output end of the rectification and filtering circuit is connected to the anode of the output power interface, and the second output end of the rectification and filtering circuit is connected to the cathode of the output power interface.
In order to more clearly explain the dc boost converter of the present invention, the steps in the embodiment of the present invention are described in detail below with reference to fig. 1.
The direct current boost converter of one embodiment of the invention comprises an input power interface 1, a coupling inductance unit 2, a half-bridge unit 3 and a bus support capacitor 4 (namely C)c) Precharge diode 5 (i.e., D)s) An isolation transformer 6, a rectifying and filtering circuit 7 and an output power interface 8 (connectable with a load R)L) The parts are described in detail as follows:
the input power interface 1 can input power with a wide voltage range such as photovoltaic power or fuel cell power.
The coupling inductance unit 2 comprises an A-phase coupling inductance LaAnd La' B phase coupling inductance LbAnd Lb', A phase continuous flow diode DaAnd B phase continuous flow diode Db。
A half-bridge unit 3 including a first bridge arm and a second bridge arm, the first bridge arm including an upper tube S1Lower tube S2The second bridge arm comprises an upper pipe S3Lower tube S4。
The isolation transformer 6 comprises a primary winding, a secondary winding and a primary leakage inductance L of the transformerr。
The rectifying and filtering circuit 7 comprises a diode D1Diode D2Diode D3Diode D4And a filter capacitor Co。
The output power interface 8 is used for outputting the power converted by the converter and can be connected with a load RLThe dc grid connection may be performed.
Input power interface 1 anode, precharge diode 5 (i.e., D)s) The anode of (A) is coupled with an inductor (L)aAnd La' the dotted terminal, B phase coupling inductance LbAnd Lb' the dotted terminal is connected with the first connection terminal T of the coupling inductance unitL1Connecting;
negative electrode of input power interface 1, bus support capacitor 4 (i.e., C)c) Negative electrode of (2) and lower tube S2Source, lower tube S4Is connected with the second connection end B of the half-bridge unit;
bus bar support capacitor 4 (i.e. C)c) Positive, pre-charge diode 5 (i.e., D)s) The cathode of the diode (D) is connected with the A continuous flow diode (D)aCathode of (D) and B-phase continuous flow diode (D)bCathode and upper tube S1Drain electrode, upper tube S3Is connected with the second connection terminal T of the coupling inductance unitL2The first connecting end A of the half-bridge unit is connected;
a phase coupling inductance LaNon-homonymous terminal, first input terminal of isolation transformer and upper tube S1Source electrode, lower tube S2Is connected with the third connection terminal C of the half-bridge unit;
b phase coupling inductance LbNon-homonymous terminal, second input terminal of isolation transformer and upper tube S3Source electrode, lower tube S4Is connected with the fourth connection end D of the half-bridge unit;
a phase coupling inductance La' non-homonymous terminal, A continuous flow diode DaIs connected with the anode of the B phase coupling inductor Lb' non-homonymous terminal and B continuous flow diode DbThe anodes of the anode groups are connected;
diode D1Anode of (2), diode D2The cathode of the isolation transformer is connected with a first connecting end of a secondary winding of the isolation transformer;
diode D3Anode of (2), diode D4The cathode of the isolation transformer is connected with a second connecting end of the secondary winding of the isolation transformer;
diode D1Cathode of (2), diode D3Cathode and filter capacitor CoAnd the positive pole of the output power interface 8 (or the load R)LPositive electrode of (1) connection;
diode D2Anode of (2), diode D4Anode and filter capacitor CoAnd the negative pole of the output power supply interface 8 (or the load R)LNegative electrode of (d) is connected.
A dc boost converter control method according to a second embodiment of the present invention is a dc boost converter control method based on the above-described dc boost converter, including:
step S10, setting the upper tube S1And a lower pipe S2Are complementary, upper tube S3And a lower pipe S4Are complementary and the upper tube S1And the lower tube S4Are the same, the lower tube S2And an upper pipe S3The duty ratio of (A) is the same; setting a phase shift angle phi between driving signals of a first bridge arm and a second bridge arm;
step S20, realizing S through the energy transfer function of the coupling inductor in the switching process1、S2、S3And S4Soft switching over the entire switching period;
step S30, modulating S at different time points in the switching period1、S2、S3And S4The control of the output voltage is realized by combining the regulation of the duty ratio of the switching tube and the phase shift angle phi of the bridge arm.
As shown in FIGS. 2 and 3, D ≦ 0.5 and D, respectively, for an embodiment of the DC boost converter of the present invention>0.5 operating waveform diagram, the operating process of the DC boost converter of the present invention is divided into 8 main states, since the states 1 to 4 and 5 to 8 are the same in principle, except the operating process from S1、S2Is transferred to S3、S4For simplicity, only states 1 to 4 will be described in detail below.
For simplicity of analysis, the following assumptions were made:
(1) all switching tubes (upper tubes and lower tubes) and diodes are ideal devices;
(2) all coupling inductors, capacitors and resistors are ideal devices;
(3) the output filter capacitor and the bus support capacitor are large enough to be used as a constant voltage source in a switching period.
As shown in fig. 4, it is a schematic diagram of an equivalent circuit structure of a circuit in state 1 of the dc boost converter according to an embodiment of the present invention:
at t0Time of day, S2Off, S1In the off state, LaThe current in (2) is in the reverse direction and is simultaneously on CS1And CS2Charging and discharging are carried out due to CS2Voltage at both ends cannot suddenly change, S2Zero voltage turn off (ZVS); when S is2When the voltage at both ends is reduced to 0V, S1Is turned on, the input voltage VinBy S1Is applied to the inductor LaUpper, LaThe current above starts to decrease in the reverse direction while the winding inductance L is coupledaThe' current also starts to decrease.
Due to S3-S4Driving signal and S of branch1-S2The duty cycle of the branches is the same and the phase difference is phi, at this stage, S4Is in a conducting state and S3In the off state, the voltage V on the bus supporting capacitorBulkBy S4And DS1Applied to the isolation transformer T, the transformer begins to deliver power to the secondary side.
As shown in fig. 5, the equivalent circuit structure diagram of the circuit of an embodiment of the dc boost converter of the present invention in state 2 is:
at t1Time of day, S1Is on due to DS1By the effect of a follow current of S1For ZVS on, this stage, LaAt VinThe current falls to 0 in the reverse direction and then starts rising in the forward direction, while the inductance L of the coupled winding is increasedaThe current on' continues to drop, at t2Time La' Up current is dropped to 0, DaAnd cutting off in the reverse direction. At this stage, S4Is still in the conducting state and S3Still in the off state, the isolation transformer T still delivers power to the secondary side.
As shown in fig. 6, the equivalent circuit structure diagram of the circuit in state 3 of the dc boost converter of the present invention is as follows:
at t2Time of day, LaThe current of' is reduced to 0, DaCutoff, S1In the on state, VinBy S1Is applied to LaIn addition, due to the coupling effect of the inductor,
Figure BDA0002509016280000101
k is the coupling coefficient of the coupling inductance, k for forward coupling>0, so LaThe current rise slope at (a) becomes smaller.
As shown in fig. 7, the equivalent circuit structure diagram of the circuit of an embodiment of the dc boost converter of the present invention in state 4 is:
at t3Time of day, S1Off, LaCurrent pair CS1And CS2Charging and discharging are carried out, and S cannot be suddenly changed due to the voltage on the capacitor1For ZVS OFF, when CS1Voltage on to VBulkWhen S is present2Is turned on, LaCurrent of (2) through DS2Freewheeling proceeds while the current begins to drop. Due to S1Turn off, simultaneously S4In the on state, the voltage drop across the isolation transformer T is 0V and the transfer of power to the secondary side is stopped.
State 5 (t)4～t5) State 6 (t)5～t6) State 7 (t)6～t7) And state 8 (t)7～t8) Lower S3-S4Working state of branch and S under state 1, state 2, state 3 and state 41-S2The working process of the branch is the same, at t8Time of day, S1And turning off, and repeating the working process of the starting state 1, so that a switching cycle is completed.
From the above analysis, it can be seen that the energy by coupling the inductanceMass transfer effect, S1、S2、S3And S4ZVS soft switching can be achieved throughout the switching cycle. Meanwhile, by adjusting the phase shift angle phi, soft switching of all switching tubes in a wide load and voltage range can be realized. The direct current boost converter can greatly reduce the switching loss under high frequency and improve the efficiency of the direct current boost converter.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process and related description of the system described above may refer to the corresponding process in the foregoing method embodiments, and will not be described herein again.
It should be noted that, the dc boost converter and the control method thereof provided in the foregoing embodiments are only illustrated by the division of the functional modules, and in practical applications, the functions may be distributed by different functional modules according to needs, that is, the modules or steps in the embodiments of the present invention are further decomposed or combined, for example, the modules in the foregoing embodiments may be combined into one module, or may be further split into a plurality of sub-modules, so as to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not to be construed as unduly limiting the present invention.
The terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing or implying a particular order or sequence.
The terms "comprises," "comprising," or any other similar term are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims (5)

1. A DC boost converter is characterized in that the converter comprises an input power interface, a coupling inductance unit, a half-bridge unit, a bus support capacitor, a pre-charging diode, an isolation transformer, a rectifying and filtering circuit and an output power interface;
the positive electrode of the input power supply interface is connected to the first connecting end T of the coupling inductance unitL1The anode of the pre-charging diode is connected with the second connecting end B of the half-bridge unit and the cathode of the bus supporting capacitor through the cathode;
the coupling inductance unit comprises an A-phase coupling inductance LaAnd La' B phase coupling inductance LbAnd Lb', A phase continuous flow diode DaAnd B phase continuous flow diode Db(ii) a The A phase coupling inductor LaAnd La' the dotted terminal, B phase coupling inductance LbAnd Lb' the same name ends are connected together to serve as a first connection end T of the coupling inductance unitL1The A phase coupling inductance La'the non-homonymous terminal of the' is connected to the A-phase continuous flow diode DaThe B phase coupling inductance Lb'the non-homonymous terminal of the' is connected to the B-phase continuous flow diode DbThe A continuous flow diode DaDiode D continuous with BbAre connected together as a second connection terminal T of the coupled inductive unitL2The A phase coupling inductance LaAs a third connection terminal T of the coupling inductance unitL3The B phase coupling inductance LbAs a fourth connection terminal T of the coupling inductance unitL4(ii) a The second connection terminal TL2The first connecting end A is connected to the positive electrode of the bus supporting capacitor, the cathode of the pre-charging diode and the first half-bridge unit; the third connection terminal TL3Is connected to the halfA third connection terminal C of the bridge unit and a first input terminal of the isolation transformer; the fourth connection terminal TL4The fourth connection end D of the half-bridge unit and the second input end of the isolation transformer are connected; the phase A coupling inductor and the phase B coupling inductor are coupled in the same direction;
the half-bridge unit comprises a first bridge arm and a second bridge arm; the first bridge arm comprises a switch tube S1Switch tube S2The second bridge arm comprises a switch tube S3Switch tube S4The switching tube Sx includes a parasitic diode Dsx and a parasitic capacitor Csx of the device, wherein x =1,2,3,4, respectively, and the switching tube S1And the switching tube S3Are connected together as a first connection A of the half-bridge unit, the switching tube S2Source electrode of and the switching tube S4Are connected together as a second connection terminal B of the half-bridge cell, the switching tube S1Source electrode of and the switching tube S2Are connected together as a third connection C of the half-bridge cell, the switching tube S3Source electrode of and the switching tube S4Are connected together as a fourth connection D of the half-bridge cell;
the first output end of the isolation transformer is connected to the first input end of the rectification and filtering circuit, and the second output end of the isolation transformer is connected to the second input end of the rectification and filtering circuit;
the first output end of the rectification and filtering circuit is connected to the anode of the output power interface, and the second output end of the rectification and filtering circuit is connected to the cathode of the output power interface.
2. The dc boost converter according to claim 1, wherein said isolation transformer comprises a primary winding, a secondary winding and a transformer primary leakage inductance Lr；
The primary side leakage inductance L of the transformerrParasitic in the isolation transformer;
the first connecting end and the second connecting end of the primary winding are respectively used as a first input end and a second input end of the isolation transformer;
and the first connecting end and the second connecting end of the secondary winding are respectively used as a first output end and a second output end of the isolation transformer.
3. The dc boost converter according to claim 1, wherein said rectifying and filtering circuit comprises a diode D1Diode D2Diode D3Diode D4And a filter capacitor Co；
The diode D1And the diode D2The cathode of the rectifier and filter circuit is connected with the first input end of the rectifier and filter circuit;
the diode D3And the diode D4The cathode of the rectifier and filter circuit is connected with the second input end of the rectifier and filter circuit;
the diode D1Cathode of (2), diode D3Cathode and filter capacitor CoAre connected together as a first output terminal of the rectifying and filtering circuit;
the diode D2Anode of (2), diode D4Anode and filter capacitor CoAre connected together as a second output of the rectifying and filtering circuit.
4. The DC boost converter according to claim 1,
the A phase coupling inductor LaAnd La', A phase continuous flow diode DaThe A-phase booster circuit is formed with the first bridge arm;
the B phase coupling inductor LbAnd Lb', B phase continuous flow diode DbAnd the second bridge arm form a B-phase booster circuit.
5. A method for controlling a DC boost converter, the method being based on the DC boost converter of any one of claims 1-4, the method comprising:
step S10, setting switch tube S1And a switching tube S2Duty cycle complementation ofSwitching tube S3And a switching tube S4Are complementary and switch tube S1And a switching tube S4Have the same duty ratio, and the switching tube S2And a switching tube S3The duty ratio of (A) is the same; setting a phase shift angle phi between driving signals of a first bridge arm and a second bridge arm;
step S20, realizing S through the energy transfer function of the coupling inductor in the switching process1、S2、S3And S4Soft switching over the entire switching period;
step S30, modulating S at different time points in the switching period1、S2、S3And S4The control of the output voltage is realized by combining the regulation of the duty ratio of the switching tube and the phase shift angle phi of the bridge arm.
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