CN114649955A - DC converter topological structure with output voltage regulation capability - Google Patents

DC converter topological structure with output voltage regulation capability Download PDF

Info

Publication number
CN114649955A
CN114649955A CN202210329439.3A CN202210329439A CN114649955A CN 114649955 A CN114649955 A CN 114649955A CN 202210329439 A CN202210329439 A CN 202210329439A CN 114649955 A CN114649955 A CN 114649955A
Authority
CN
China
Prior art keywords
converter
resonant
output
llc
synchronous rectification
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210329439.3A
Other languages
Chinese (zh)
Inventor
陈材
伍纵横
胡至祎
康勇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huazhong University of Science and Technology
Original Assignee
Huazhong University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huazhong University of Science and Technology filed Critical Huazhong University of Science and Technology
Priority to CN202210329439.3A priority Critical patent/CN114649955A/en
Publication of CN114649955A publication Critical patent/CN114649955A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H02M3/33592—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices

Landscapes

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

Abstract

The invention discloses a direct current converter topological structure with output voltage regulation capacity, which belongs to the technical field of direct current-direct current converter topological structures and comprises two transmission paths for transmitting energy from an input port to an output port. The main channel is an LLC resonant converter operating at a fixed switching frequency, transferring most of the input energy to the load. The auxiliary channel comprises two stages, the first stage adopts a small LLC resonant converter to realize high-efficiency isolation conversion, then a non-isolation type PWM direct current converter is cascaded with the LLC resonant converter, and the output voltage is regulated by regulating the PWM direct current converter. The main channel and the auxiliary channel are connected in parallel at the input port, and the output ports are connected in series. The invention simplifies the control strategy and the synchronous rectification logic, and most of the input energy is transferred to the load by the single-stage main channel, thereby obviously reducing the energy loss. Thus, the proposed converter topology achieves high efficiency and high power density.

Description

DC converter topological structure with output voltage regulation capability
Technical Field
The invention belongs to the technical field of direct current-direct current converter topological structures, and particularly relates to a direct current converter topological structure with output voltage regulation capacity.
Background
Thanks to the rapid development of the information industry, data centers are configured with more servers, and power consumption is increased. As output power increases, the power supply takes up more server rack space. In order to reduce energy loss and improve space utilization, it is necessary to achieve high efficiency and high power density in the energy conversion stage.
Conventional hard-switched Pulse Width Modulation (PWM) converters are widely used in industrial power delivery systems. However, the large losses generated by hard switching prevent further improvements in efficiency and power density. Therefore, a converter under hard switching is not suitable for a server power supply with high requirements on efficiency and power density.
The single-stage DC-DC LLC resonant converter is widely applied to occasions requiring electrical isolation and high efficiency. In general, the LLC converter can realize zero-voltage turn-on (ZVS) and turn-off with a small turn-off current on a primary side switching tube, and can realize zero-current turn-off (ZCS) on a secondary side switching tube. It greatly reduces the switching loss and makes high frequency switching possible. For a single stage LLC converter, the output voltage can be regulated by adjusting the phase shift angle, switching frequency, or duty cycle, but this requires a large resonant inductance, sacrificing efficiency and power density. In addition, for high frequency regulated LLC converters with phase shift modulation or frequency modulation, it is difficult to obtain an effective control strategy, and the logic of synchronous rectification is also difficult to implement.
The LLC converter exhibits optimum performance at the series resonant frequency, i.e., zero-voltage-on-switching (ZVS) of the primary device, low-current turn-off, and zero-current-off (ZCS) of the secondary synchronous rectifier can be achieved simultaneously, thereby achieving high efficiency and high power density. LLC converters with fixed frequency and no regulation function have been proven to work at MHz, but LLC resonant converters with fixed switching frequency can only provide a fixed transformation ratio, and thus their output voltage will fluctuate with input voltage and load current.
In order to fully utilize the advantages of the LLC resonant converter and meet the requirement of output voltage regulation, researchers have proposed a two-stage LLC resonant converter solution. By separating the voltage regulation function from the electrical isolation function, each stage can be optimized respectively and conveniently, and the control strategy and the synchronous rectification logic are easy to realize. However, in conventional two-stage designs, the regulator stage is required to deliver the entire load power, thereby introducing larger size components that reduce efficiency and power density. In order to obtain output regulation capability and improve conversion efficiency, another group of researchers have proposed a quasi-single-stage structure, that is, in a sigma converter, most of energy is directly transmitted to a load by an LLC resonant converter, and only part of energy is regulated by a buck converter, so that output regulation capability and higher conversion efficiency are obtained. But buck converters cannot achieve electrical isolation. In order to realize electrical isolation, some new structures are proposed on the basis of a sigma converter, but the problems of increased equipment voltage and current stress, reduced efficiency and the like caused by circulating energy in the converter exist.
Therefore, for the dc-dc converter with the output voltage regulation capability and the LLC resonant converter operating at a fixed switching frequency, it is necessary to further optimize its structure and control strategy, so as to improve its power density and efficiency, and simplify its control strategy and control logic of synchronous rectification as much as possible, and obtain good dynamic performance, i.e. to keep the output voltage stable when the input voltage and the load change within a certain range.
Disclosure of Invention
The invention aims to provide a direct current converter topological structure with output voltage regulation capability, and aims to solve the technical problems that the existing LLC resonant converter with the output voltage regulation capability has the disadvantages of low power density, low efficiency, complex control strategy, difficult realization of synchronous rectification control logic and the like due to the topological structure.
The technical scheme for solving the technical problems is as follows: a direct current-direct current converter topology structure with an output voltage regulation capability and an LLC resonant converter working at a fixed switching frequency comprises two transmission paths for transferring energy from an input port to an output port. The main channel transfers most of the energy input to the output port. The auxiliary channel comprises two stages for processing the regulated portion of the input power. The input ports of the main channel and the auxiliary channel are connected in parallel, and the output ports of the main channel and the auxiliary channel are connected in series;
the main channel is an LLC resonant converter which works at a fixed switching frequency and transmits most of input energy to an output port;
the auxiliary channel comprises two stages, the first stage adopts a small LLC resonant converter to realize efficient isolation conversion, and the second stage adopts a non-isolation PWM direct current-direct current converter to be cascaded with the small LLC resonant converter. The output voltage is regulated by a cascaded non-isolated PWM DC-DC converter of the regulating auxiliary channel.
The invention has the beneficial effects that: since the voltage regulation of the topology is achieved at a fixed switching frequency, the architecture simplifies the control strategy and the synchronous rectification logic. Compared with the common two-stage scheme, most of energy input by the structure is transferred to the load by the main channel with a single stage, and only a small part of energy is transferred to the load by the auxiliary channel with the two-stage structure, so that the energy loss is remarkably reduced. Thus, the proposed converter topology achieves high efficiency and high power density.
On the basis of the technical scheme, the invention can be further improved as follows.
Further, the LLC resonant converter used by the energy transmission main channel and the LLC resonant converter used by the auxiliary channel both operate at the series resonant frequency of the respective resonant cavities.
Further, the switching frequency of the PWM converter used by the energy transfer auxiliary channel is independent of the two LLC resonant converters.
The invention has the further beneficial effects that: the LLC resonant converters of the energy transmission main channel and the auxiliary channel can obtain stable transformation ratio, the advantages of high efficiency and high power density of the LLC resonant converter are reserved, the LLC resonant converter does not need to be additionally controlled, and only the PWM converter needs to be controlled to regulate the output voltage.
Further, the LLC resonant converter used for the energy transmission main channel and the LLC resonant converter used for the energy transmission auxiliary channel work under the same series resonant frequency and duty ratio through proper resonant cavity parameter design, in the structure, square wave input voltage is respectively introduced into the two energy transmission paths by not adopting two completely same bridge arms, but the two bridge arms are combined into one bridge arm, the two energy transmission paths are connected with completely same square wave direct current input voltage, and completely same square wave voltage is output.
The invention has the following further beneficial effects: the topology of the circuit is greatly simplified.
Further, the LLC resonant converter of the main channel and the LLC resonant converter of the auxiliary channel share one group, and the group is composed of a first switch tube Q1And a second switching tube Q2Formed half bridge arm, input voltage VinVia an input filter capacitor CinThe filtered signal is applied to the first switch tube Q1And a second switching tube Q2Two ends of the formed half-bridge arm are connected with a first switch tube Q1And a second switching tube Q2And the middle point output of the formed half-bridge arm.
The main channel comprises a first resonant inductor Lr1A first resonant capacitor Cr1With a first excitation inductance Lm1First center-tapped transformer T1A first synchronous rectification switch tube S1A second synchronous rectification switch tube S2And a first output filter capacitor Co1First resonant inductor Lr1A first resonant capacitor Cr1And with a first excitation inductance Lm1First center-tapped transformer T1The primary side of the first resonant cavity is connected in series to form a first resonant cavity, and the input of the first resonant cavity is a first switching tube Q1And a second switching tube Q2The voltage output from the midpoint of the half-bridge arm with the first excitation inductor Lm1First center-tapped transformer T1The secondary side of the transformer is connected with a first synchronous rectification switching tube S1A second synchronous rectification switch tube S2Formed synchronous rectifier, first center-tapped transformer T1The voltage output by the secondary side passes through a first synchronous rectification switching tube S1And a second synchronous rectification switching tube S2After being rectified, the voltage is filtered by a first output filter capacitor Co1And (6) filtering.
Further, the auxiliary channel comprises a second resonant inductance Lr2A second resonant capacitor Cr2With a second excitation inductance Lm2A second center-tapped transformer Tx and a third synchronous rectification switch tube S3And the fourth synchronous rectification switch tube S4And a second output filter capacitor Co2Second resonant inductor Lr2A second resonant capacitor Cr2And with a second excitation inductance Lm2Second center-tapped transformer T2The primary side of the first resonant cavity is connected in series to form a second resonant cavity, and the input of the second resonant cavity is a first switching tube Q1And a second switching tube Q2Voltage output from midpoint of half-bridge arm with second exciting inductance Lm2Second center-tapped transformer T2The secondary side of the first synchronous rectification switch tube S is connected with a second synchronous rectification switch tube S3And the fourth synchronous rectification switch tube S4Formed synchronous rectifier, second center-tapped transformer T2The voltage output by the secondary side passes through a third synchronous rectification switching tube S3And a fourth synchronous rectification switching tube S4After being rectified, the voltage is filtered by a second output filter capacitor Co2And (6) filtering.
Further, the primary side switching tube Q of the topological structure1And Q2A gallium nitride device is used.
The invention has the further beneficial effects that: the turn-off loss of the primary side switching tube is greatly reduced.
Further, the topological structure of the synchronous rectifier S1-S4Silicon devices are used.
The invention has the further beneficial effects that: the conduction loss of the secondary side rectifier bridge under the condition of high output current is greatly reduced.
Further, a driving signal of the synchronous rectifier of the topological structure is synchronous with a driving signal of the primary side switching tube, and the synchronous rectifier has fixed frequency and duty ratio.
Compared with the prior art, the invention simplifies the control strategy and the synchronous rectification logic, and most of the input energy is transferred to the load from the single-stage main channel, thereby obviously reducing the energy loss. Thus, the proposed converter topology achieves high efficiency and high power density.
Drawings
Fig. 1 is a schematic block diagram of a dc converter topology proposed in the present invention;
FIG. 2 is a schematic diagram of the original circuit topology of the DC converter proposed in the present invention;
FIG. 3 is a simplified circuit topology of the DC converter proposed in the present invention;
fig. 4 is a main waveform diagram of the dc converter proposed in the present invention in a steady state;
FIG. 5 is an equivalent circuit diagram of each stage of the DC converter proposed in the present invention in steady state, wherein (a), (b), and (c) are t in FIG. 40～t1、t1～t2、t2～t3Equivalent circuit diagrams corresponding to the time intervals;
fig. 6 is a schematic diagram of a circuit topology of a dc converter according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Fig. 1 is a schematic block diagram of a dc converter topology and its output voltage regulation principle proposed in the present invention. In this topology, the energy transfer from the input port to the output port can be divided into two transmission paths, and these two paths are called a main channel and an auxiliary channel as the channels for energy transfer. The main channel transmits most of the input energy to the output port, and the main channel is composed of only one LLC resonant converter working at a fixed switching frequency, specifically, the main channel for energy transmission is composed of a single LLC resonant converter working at a fixed switching frequency, which converts the input dc voltage into the output dc voltage and undertakes most of the work of the converter to transmit energy. The auxiliary channel is responsible for energy transfer only for the majority of the energy input to the output port, but it also assumes the task of regulating the output voltage. In particular, the auxiliary channel comprises a total of two stages, the first stage being a small LLC resonant converter, in particular also an LLC resonant converter operating at a fixed switching frequency. The small LLC resonant converter is also required to be cascaded with a non-isolated PWM DC-DC converter, such as a Buck converter, a Boost converter and the like, in an auxiliary channel, and the cascaded DC converter is used for processing a regulated part of input energy. In addition, the input ports of the main channel and the auxiliary channel are connected in parallel, and the output ports are connected in series.
In FIG. 1, VinThe input voltage of the DC converter is formed by connecting the main path and the auxiliary path of energy transmission in parallel, so that the input voltage of the main path and the auxiliary path of energy transmission is Vin；VmainIs an input voltage VinThe output voltage of the energy transmission main path is obtained by performing direct current-direct current conversion through an LLC resonant converter on the energy transmission main path; pmainThe energy flows out from the output port after passing through the energy transmission main path in the input total energy; vauxIs an input voltage VinThe output voltage of the energy transmission auxiliary path is obtained after two times of direct current-direct current conversion of the LLC resonant converter and the non-isolated PWM direct current converter on the energy transmission auxiliary path; pauxThe energy which flows out from the output port after passing through the energy transmission auxiliary path in the input total energy; output voltage Vo(Vout) The total voltage output by the proposed DC converter is V because the main path and the auxiliary path of energy transmission are connected in series at the output porto＝Vmain+Vaux。
When the input voltage is according to V shown in fig. 1inWhen the line graph of (2) is changed, since the LLC resonant converter on the main path of energy transfer operates at a fixed switching frequency, the gain of the output voltage on the main path is not changed, i.e. VmainThe trend sum V ofinSame, at this time, only VauxThe change trend of (1) and V in the graphauxAre in line with each other, and output voltage VoCan it remain constant. In this structure, since VmainAnd VoThe two energy transmission paths are connected in series, so that only a part of energy which is small in proportion to the total input energy passes through the two-stage direct current conversion structure of the auxiliary energy transmission path, namely, the energy lost on the hard-switching non-isolated PWM converter is small. Within a certain regulation range, the power loss is small.
FIG. 2 is a schematic diagram of the original circuit topology of the DC converter proposed in the present invention, LLC1Is an LLC resonant converter operating at a fixed switching frequency in the main energy transmission path, wherein Q1And Q2Form the bridge arm, Q of the input square wave voltage of the primary side of the transformer1Is an upper switch tube, Q of the bridge arm2A lower switching tube of the bridge arm, Lr1Is LLC1Resonant inductance of, Cr1Is LLC1Resonant capacitance of Lm1Is LLC1Excitation inductance of, T1Is LLC1The turn ratio of the center-tapped transformer of (1) to (1), S1And S2Is LLC1Secondary side synchronous rectification switching tube ofo1Is the output voltage of the main path of energy transmission, Co1Is a capacitor for output voltage stabilization and filtering of the energy transmission main path.
LLC2Is a small LLC resonant converter operating at a fixed switching frequency in the auxiliary path of energy transfer, where Q3And Q4Form the bridge arm, Q of the input square wave voltage of the primary side of the transformer3Is an upper switch tube, Q of the bridge arm4A lower switching tube of the bridge arm, Lr2Is LLC2Resonant inductance of, Cr2Is LLC2Resonant capacitance of Lm2Is LLC2Excitation inductance of, T2Is LLC2The turn ratio of the center-tapped transformer (1: 1, S)3And S4Is LLC2Secondary side synchronous rectification switching tube ofo2Is LLC2Output voltage of Co2Is used for LLC2The output voltage stabilization and the filtering capacitor. Vo3Is the output voltage of the PWM converter in the auxiliary path for energy transfer, Co3Is a capacitor for output voltage stabilization and filtering of the energy transmission auxiliary path. CinIs a capacitor for input voltage stabilization and filtering, RLIs the load resistance of the proposed converter.
In fig. 2, the switching frequency of the non-isolated PWM converter is independent of the two LLC resonant converters, and by changing the duty cycle of the PWM converter, the magnitude of the output voltage of the auxiliary energy transmission path can be adjusted, thereby adjusting the output voltage of the entire converter. Since in the proposed circuit topology the factors causing the output voltage variation are mainly the input voltage and the load current, the duty cycle of the PWM converter is determined by the output voltage and the load current together through a feedback control loop.
FIG. 3 is a simplified circuit topology diagram of the DC converter proposed in the present invention, which is due to LLC1And LLC2The LLC resonant converter can work under the condition of fixed switching frequency, and the LLC resonant converter can enable the primary side switching tube to be switched on at zero voltage, switched off at low voltage and the secondary side rectifier to be switched off at zero current when the switching frequency is equal to the series resonant frequency of the resonant cavity, so that the LLC resonant converter has the highest efficiency and power density and the best performance. Therefore, in the present invention, LLC1And LLC2Are operated at the series resonant frequency of their respective resonant cavities. By designing respective resonant cavity parameters, LLC1And LLC2Have the same series resonance frequency, i.e. LLC1And LLC2Have the same switching frequency, so that the reference Q in FIG. 21And Q2Bridge arm formed of Q3And Q4The bridge arm composition is represented by Q in FIG. 31And Q2The bridge arm is formed.
By making two bridge arms work at the same switching frequency, the switching frequency is LLC1And LLC2Of series resonant frequency, LLC1And LLC2The best performance, i.e. high efficiency, high power density, and LLC1And LLC2The driving signals required by the primary side switching tube and the secondary side rectifier are completely oneTherefore, the control strategy and the control logic of synchronous rectification are greatly simplified. Meanwhile, the two bridge arms in fig. 2 are combined into one bridge arm in fig. 3, so that the complexity of the circuit can be greatly reduced.
FIG. 4 is a main waveform diagram of the circuit topology of the DC converter proposed in the present invention, and (a), (b), (c) in FIG. 5 are t in FIG. 40～t1、t1～t2、t2～t3Equivalent circuit diagram corresponding to the time interval. V in FIG. 4gs_Q1And Vgs_Q2Are respectively a primary side switching tube Q1And Q2All the driving signals of LLC1And LLC2Series resonant frequency, V, of the resonant cavityds_QIs a primary side switching tube Q2The drain-source voltage of (1). i.e. ir1Is LLC1Resonant current of (i)m1Is LLC1Excitation current of is1、is2Are respectively LLC1The secondary rectifier of (2). i.e. ir2Is LLC2Resonant current of im2Is LLC2Excitation current of is3、is4Are respectively LLC2The secondary rectifier of (2).
FIG. 5 (a) is the proposed circuit topology t in FIG. 40～t1Equivalent circuit diagram of time period, wherein Q1At t0When the resonant cavity is switched on, the resonant cavity starts to oscillate, and the resonant current is a section of sine wave. At the same time, the secondary rectifier tube S1And S3At t0Time-on, excitation inductance Lm1Is clamped by the output voltage, Lm1The voltage across is nVo1I.e. Vin2; excitation inductance Lm2Is also clamped by the output voltage, Lm2Voltage at both ends is mVo2I.e. Vin/2. Thus Lm1And Lm2The current flowing upwards increases linearly, the resonance current and the excitation current shift, and the energy passes through Q1、T1、T2、S1、S3To the load.
FIG. 5 (b) is the proposed circuit topology t in FIG. 41～t2Equivalent circuit diagram of time period int1～t2In the period, the resonant current is equal to the exciting current, and the current i flowing through the secondary rectifier tubes1And is3Equal to 0, secondary rectifier tube S1And S3And the zero-current turn-off of the secondary rectifier tube is realized. Meanwhile, the excitation inductor is no longer clamped by the output voltage, but resonates with the resonant inductor and the resonant capacitor, and the resonant inductor and the resonant capacitor resonate together at t2Moment, primary side switch tube Q1Has been turned off. At t1～t2The input voltage no longer transfers energy from the primary side to the output side during the dead time, and the output voltage is maintained by the output capacitor. The most important purpose of setting the dead time is to enable the primary side switching tube Q2Secondary side rectifier tube S2、S4Until their respective drain-source voltages are equal to 0, so that zero-voltage switching-on is achieved in the next stage.
In fig. 5 (c) is t in fig. 4 for the proposed circuit topology2～t3Equivalent circuit diagram of time period, at t2Moment, primary side switch tube Q2Secondary side rectifier tube S2、S4And when the resonant cavity is switched on, the input voltage is applied to the resonant cavity again, the resonant inductor and the resonant capacitor continue to resonate, and the resonant current is a section of sine wave. Excitation inductance Lm1Is clamped by the output voltage, Lm1The voltage across is-nVo1I.e. -Vin2; excitation inductance Lm2Is also clamped by the output voltage, Lm2The voltage across both ends is-mVo2I.e., -Vin/2. Thus Lm1And Lm2The current flowing upwards is changed linearly, the slope of the change is negative, the resonance current and the excitation current are deviated, and the energy passes through Q2、T1、T2、S2、S4To the load. To t3At the moment, the resonant current and the exciting current are equal, and the primary side switching tube Q2Secondary side rectifier tube S2、S4Zero current is turned off.
T in FIG. 43～t4In time period, due to the primary side switching tube Q2Secondary side rectifier tube S2、S4Has been at t3At the moment the zero current is switched off,the circuit is at t3Another dead time is entered, and the equivalent circuit at this time is similar to (b) in fig. 5. The exciting inductor is no longer clamped by the output voltage, but resonates with the resonant inductor and the resonant capacitor, and at t4Moment, primary side switch tube Q2Has been turned off. At t3～t4The input voltage no longer transfers energy from the primary side to the output side during the dead time, and the output voltage is maintained by the output capacitor. At t3～t4Primary side switch tube Q in time period1Secondary side rectifier tube S1、S3Until their respective drain-source voltages are equal to 0, so that zero-voltage switching-on is achieved in the next stage.
Fig. 6 is a schematic diagram of a circuit topology of a dc converter according to an embodiment of the present invention, and the auxiliary energy transmission channel of the circuit topology shown in fig. 1, 2, 3, and 5 requires a non-isolated PWM converter such as a Buck converter, a Boost converter, and a DCX converter2And (4) cascading. In the present embodiment, the non-isolated PWM converter is a Buck converter. The Buck converter is composed of a switch tube Q3、Q4A pair of bridge arms and an inductor L1Capacitor Co3Is formed of a switching tube Q3Is an upper switch tube and a switch tube Q of the bridge arm4Is the lower switch tube of the bridge arm. And the primary side switching tube adopts gallium nitride (GaN) equipment to reduce turn-off loss, and the secondary side rectifier adopts silicon (Si) equipment to reduce conduction loss.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (9)

1. A dc converter topology with output voltage regulation capability, comprising two transmission paths for transferring energy from an input port to an output port: the input ports of the main channel and the auxiliary channel are connected in parallel, and the output ports of the main channel and the auxiliary channel are connected in series;
the main channel is an LLC resonant converter, which operates at a fixed switching frequency;
the auxiliary channel comprises two stages, the first stage adopts an LLC resonant converter, the second stage adopts a non-isolated PWM DC-DC converter to be cascaded with the first stage, and the output voltage is regulated by regulating the cascaded non-isolated PWM DC-DC converter of the auxiliary channel.
2. A DC converter topology according to claim 1, characterized in that the LLC resonant converter used for the main channel and the LLC resonant converter used for the auxiliary channel both operate at the series resonant frequency of the respective resonant cavities.
3. The dc converter topology of claim 1, wherein a switching frequency of a PWM converter used by an auxiliary channel is independent of two LLC resonant converters.
4. The direct current converter topology structure according to claim 1 or 2, wherein the LLC resonant converter used in the main channel and the LLC resonant converter used in the auxiliary channel operate at the same series resonant frequency and duty ratio, and the main channel and the auxiliary channel share a bridge arm, are connected to the same direct current input voltage, and output the same square wave voltage.
5. The DC converter topology of claim 4, wherein the LLC resonant converter of the main channel and the LLC resonant converter of the auxiliary channel share a set of Q by a first switch tube1And a second switching tube Q2Formed half bridge arm, input voltage VinVia an input filter capacitor CinThe filtered signal is applied to the first switch tube Q1And a second switching tube Q2Two ends of the formed half-bridge arm are connected with a first switch tube Q1And a second switching tube Q2And the middle point output of the formed half-bridge arm.
6. Root of herbaceous plantThe DC converter topology of claim 5, wherein the main channel comprises a first resonant inductor Lr1A first resonant capacitor Cr1With a first excitation inductance Lm1First center-tapped transformer T1A first synchronous rectification switch tube S1A second synchronous rectification switch tube S2And a first output filter capacitor Co1First resonant inductor Lr1A first resonant capacitor Cr1And with a first excitation inductance Lm1First center-tapped transformer T1The primary side of the first resonant cavity is connected in series to form a first resonant cavity, and the input of the first resonant cavity is a first switching tube Q1And a second switching tube Q2The voltage output by the midpoint of the half-bridge arm is provided with a first excitation inductor Lm1First center-tapped transformer T1The secondary side of the transformer is connected with a first synchronous rectification switching tube S1A second synchronous rectification switch tube S2Formed synchronous rectifier, first center-tapped transformer T1The voltage output by the secondary side passes through a first synchronous rectification switching tube S1And a second synchronous rectification switching tube S2After being rectified, the voltage is filtered by a first output filter capacitor Co1And (5) filtering.
7. The DC converter topology of claim 5, wherein the auxiliary channel comprises a second resonant inductor Lr2A second resonant capacitor Cr2With a second excitation inductance Lm2Second center-tapped transformer T2And the third synchronous rectification switch tube S3And the fourth synchronous rectification switch tube S4And a second output filter capacitor Co2Second resonant inductor Lr2A second resonant capacitor Cr2And with a second excitation inductance Lm2Second center-tapped transformer T2The primary side of the first resonant cavity is connected in series to form a second resonant cavity, and the input of the second resonant cavity is a first switching tube Q1And a second switching tube Q2Voltage output from midpoint of half-bridge arm with second exciting inductance Lm2Second center-tapped transformer T2The secondary side of the first synchronous rectification switch tube S is connected with a second synchronous rectification switch tube S3The fourth synchronizationRectifier switch tube S4Formed synchronous rectifier, second center-tapped transformer T2The voltage output by the secondary side passes through a third synchronous rectification switching tube S3And a fourth synchronous rectification switching tube S4After being rectified, the output voltage passes through a second output filter capacitor Co2And (6) filtering.
8. The dc converter topology of claim 1, wherein a drive signal of a synchronous rectifier of the topology is synchronous with a drive signal of a primary side switching tube, and has the same and fixed frequency and duty cycle.
9. The dc converter topology of claim 1, wherein the PWM dc-dc converter is a Buck converter or a Boost converter.
CN202210329439.3A 2022-03-30 2022-03-30 DC converter topological structure with output voltage regulation capability Pending CN114649955A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210329439.3A CN114649955A (en) 2022-03-30 2022-03-30 DC converter topological structure with output voltage regulation capability

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210329439.3A CN114649955A (en) 2022-03-30 2022-03-30 DC converter topological structure with output voltage regulation capability

Publications (1)

Publication Number Publication Date
CN114649955A true CN114649955A (en) 2022-06-21

Family

ID=81994624

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210329439.3A Pending CN114649955A (en) 2022-03-30 2022-03-30 DC converter topological structure with output voltage regulation capability

Country Status (1)

Country Link
CN (1) CN114649955A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4336718A1 (en) * 2022-09-09 2024-03-13 Infineon Technologies Austria AG Switching converter using partial power processing

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4336718A1 (en) * 2022-09-09 2024-03-13 Infineon Technologies Austria AG Switching converter using partial power processing

Similar Documents

Publication Publication Date Title
CN111490683B (en) Trajectory control method for double-transformer series resonance double-active bridge DC-DC converter topology
US7573731B2 (en) Active-clamp current-source push-pull DC-DC converter
CN100353654C (en) Cascading bidirectional DC-DC converter
CN109756142B (en) Reconfigurable H5 inverter bridge and single-directional resonant converter based on inverter bridge
CN110719035B (en) Topological structure of single-stage DAB-LLC hybrid bidirectional DC-DC converter
EP3734824B1 (en) Method for controlling a power conversion circuit and related power conversion circuit
CN110798073A (en) Wide voltage range output current feed converter
CN110190752B (en) Bidirectional CLLLC-DCX resonant converter and control method thereof
CN110165895B (en) Circuit structure and control method for realizing wide-gain FB-HB LLC resonant converter
CN109842299B (en) Combined direct current conversion system and control method thereof
CN110829855A (en) LLC converter switching over wide voltage range based on alternating current switch
CN111064370B (en) LLC and DAB mixed bidirectional DC-DC converter
WO2022000217A1 (en) Resonant converter, and voltage conversion method
CN104702115A (en) Method of equally dividing power of input-parallel output-parallel modularized DC (Direct Current) converter
CN109302078B (en) DC-DC switching power supply based on synchronous rectification mode
CN114649955A (en) DC converter topological structure with output voltage regulation capability
CN107171563B (en) The combined converter of tight adjustment output
CN110224605B (en) Full-bridge conversion circuit
CN110995011B (en) Bidirectional DC-DC converter based on alternating current switch switching
CN115441746A (en) Direct current converter topological structure with adjustable output voltage in wide input range
CN109194135B (en) Adaptive efficiency optimization method of power converter with adjustable resonance state
CN113890375B (en) Bi-polar output bi-directional LLC resonant converter topology
CN116111830A (en) Half-bridge-full-bridge combined LLC resonant direct-current converter based on double transformers
CN115149809A (en) Non-isolated full-bridge cascaded converter circuit and control method thereof
CN108494260A (en) A kind of soft switch circuit

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination