CN110739859A

CN110739859A - symmetrical half-bridge resonant open-loop DC proportional converter

Info

Publication number: CN110739859A
Application number: CN201911190082.XA
Authority: CN
Inventors: 高彧博; 杭磊; 程立; 李群; 谢章贵
Original assignee: Yangzhou Institute Of Marine Electronic Instruments No723 Institute Of China Shipbuilding Industry Corp
Current assignee: Yangzhou Institute Of Marine Electronic Instruments No723 Institute Of China Shipbuilding Industry Corp
Priority date: 2019-11-28
Filing date: 2019-11-28
Publication date: 2020-01-31
Anticipated expiration: 2039-11-28
Also published as: CN110739859B

Abstract

The application discloses symmetrical half-bridge resonant open-loop direct-current proportional converter which comprises a high-frequency pulse width controller and a high-frequency grid driver, wherein the output end of the high-frequency pulse width controller is connected with the input end of the high-frequency grid driver, the high-frequency pulse width controller is used for inputting a control signal to the high-frequency grid driver, the output end of the high-frequency grid driver is connected with the primary end of an isolation driving transformer, the high-frequency grid driver is used for enhancing the current driving capability of the control signal, the secondary end of the isolation driving transformer is respectively connected with the control end of a symmetrical half-bridge switching circuit and the control end of a high-frequency synchronous rectification filter circuit, and the isolation driving transformer is used for driving the conduction or the disconnection of a half-bridge transistor in the symmetrical half-bridge switching circuit and a full-bridge synchronous rectification transistor in the high-frequency synchronous rectification filter circuit according to the enhanced control signal.

Description

symmetrical half-bridge resonant open-loop DC proportional converter

Technical Field

The application relates to the technical field of direct current conversion, in particular to symmetrical half-bridge resonant open-loop direct current proportional converters.

Background

With the development of power semiconductor devices, topology circuits and switching power supply controllers, the technical indexes of the switching power supply, such as power density, reliability, efficiency, stability, load response capability and the like, are also continuously improved.

The voltage stabilizing method of the switch power supply is to adjust the switch control pulse through the negative feedback compensation network to achieve the purpose of stabilizing the output voltage, through sampling variables or two variables such as the output voltage, the input current or the output current, and the like, comparing the error with the control reference for post-processing, and according to the different sampling signals, the current control loop, the voltage control loop or the double loop control can be divided, and according to the sampling points, the primary feedback (feedforward) and the secondary feedback can be divided in different windings of the switch transformer.

However, in the prior art, the voltage stabilization modes are closed-loop feedback, and are selected according to different response speeds of a feedback loop, such as voltage stabilization accuracy, source characteristics, load characteristics, and the like, the voltage stabilization accuracy is high, but due to the time delay of primary and secondary isolated sampling and the nonlinearity of a compensation network, the response speed of the feedback loop is slow, the stability is poor, the feedback loop with excellent regulation parameter optimization needs dozens of switching cycles to adjust sudden load changes, and the loop is easy to generate a self-oscillation phenomenon.

In addition, the switching power supply operating in the closed-loop feedback mode controls the energy transmitted to the secondary according to the conduction pulse width, the phase relationship or the operating frequency of the feedback signal adjusting transistor, so as to realize the voltage stabilization of the output voltage.

Disclosure of Invention

The purpose of this application lies in: the circuit topological structure of the split-ring proportional converter is optimized, so that the converter has high response speed to a load and high stability, oscillation factors of a feedback loop do not exist, the bridge switch cannot be switched on by mistake to be used for a common fryer, and the reliability is high.

The technical scheme includes that the symmetrical half-bridge resonance open-loop direct-current proportional converter comprises a symmetrical half-bridge switching circuit, an LC series resonant circuit, a high-frequency power transformer, a high-frequency synchronous rectification filter circuit, a fixed-width high-frequency driving control circuit and an isolation driving transformer, wherein the symmetrical half-bridge switching circuit, the LC series resonant circuit, the high-frequency power transformer and the high-frequency synchronous rectification filter circuit are sequentially connected with one another, the fixed-width high-frequency driving control circuit comprises a high-frequency pulse width controller and a high-frequency gate driver, the output end of the high-frequency pulse width controller is connected to the input end of the high-frequency gate driver, the high-frequency pulse width controller is used for inputting a control signal to the high-frequency gate driver, the output end of the high-frequency gate driver is connected to the primary end of the isolation driving transformer, the high-frequency gate driver is used for enhancing the current driving capability of the control signal, the secondary end of the isolation driving transformer is respectively connected to the control end of the symmetrical half-bridge switching circuit and the control end of the high-frequency synchronous rectification filter circuit, the isolation.

In the aforementioned any technical solution, the LC series resonant circuit and the high frequency power transformer in steps comprise an LCT integrated magnetic element, where the LCT integrated magnetic element includes a th primary planar winding of the high frequency transformer, a secondary planar winding of the second high frequency transformer, and the magnetic element further includes a parasitic capacitor and a parasitic inductor, the parasitic capacitor is tightly coupled below the primary planar winding of the th primary planar winding of the high frequency transformer and above the primary planar winding of the second high frequency transformer, and the parasitic inductor is tightly coupled below the primary planar winding of the second high frequency transformer and above the secondary planar winding of the high frequency transformer, where the parasitic capacitor and the parasitic inductor form the LC series resonant circuit.

In any technical solutions, in the step , the primary planar winding of the th high-frequency transformer is composed of three layers of printed circuit boards, a th buried via interlayer transition region is arranged on each printed circuit board, two adjacent layers of printed circuit boards are interconnected through the th buried via interlayer transition region, and turns of winding printed lines are printed on each layer of printed circuit boards.

In any of the above solutions, in step , the primary planar winding of the second high frequency transformer is composed of three layers of printed circuit boards, each layers of printed circuit boards are printed with turns of winding printed lines, and the winding printed lines of the th layer of printed circuit board of the primary planar winding of the second high frequency transformer are the same as the winding printed lines of the third layer of printed circuit board of the primary planar winding of the high frequency transformer.

In any technical solutions, , the secondary planar winding of the high-frequency transformer is composed of two layers of printed circuit boards, a third buried via interlayer transition region is disposed on the printed circuit board, the two layers of printed circuit boards are connected in parallel through the third buried via interlayer transition region, turns of winding tracks are printed on each layers of printed circuit boards, and the winding tracks on the two layers of printed circuit boards have the same shape.

In any of the solutions, at step , six coils are disposed at a secondary side of the isolation driving transformer, an th coil and a second coil are connected to a th driving circuit, and a third coil, a fourth coil, a fifth coil and a sixth coil are connected to a second driving circuit, wherein the th coil, the third coil and the fifth coil are th dotted terminals, the second coil, the fourth coil and the sixth coil are second dotted terminals, and th dotted terminals and the second dotted terminals are phase-interleaved.

In any of the technical solutions, in the step , the symmetric half-bridge switching circuit is a symmetric half-bridge switching circuit composed of two half-bridge transistors, two voltage-sharing capacitors, two voltage-sharing resistors and a high-frequency power transformer, and is characterized in that the th driving circuit includes two ways of th gate voltage-dividing driving circuits, and the th coil and the second coil are connected to the gates of the two half-bridge transistors connected in series in the symmetric half-bridge switching circuit through the two ways of th gate voltage-dividing driving circuits, respectively.

In any of the technical solutions, in step , the high-frequency synchronous rectification filter circuit is a synchronous high-frequency synchronous rectification filter circuit composed of four synchronous rectification transistors and a filter capacitor, and the four synchronous rectification transistors are connected to the secondary side of the high-frequency power transformer, and the second driving circuit includes four paths of second gate voltage division driving circuits, and a third coil, a fourth coil, a fifth coil and a sixth coil are sequentially connected to gates of the four synchronous rectification transistors in the synchronous high-frequency synchronous rectification filter circuit through the four paths of second gate voltage division driving circuits.

In any of the above solutions, the th gate voltage dividing driving circuit is configured to have the same structure as the 0 th gate voltage dividing driving circuit, and the 1 th gate voltage dividing driving circuit includes four high frequency diodes, a transient suppression diode and three gate driving circuit resistors, wherein a cathode of the 2 th high frequency diode is connected to an anode of the second high frequency diode and connected to a positive terminal of the coil, an anode of the th high frequency diode is connected to a terminal of the th gate driving circuit resistor, the second high frequency diode, the third high frequency diode and the fourth high frequency diode are connected in series in phase, a cathode of the fourth high frequency diode is connected to a terminal of the second gate driving circuit resistor, an other terminal of the second gate driving circuit resistor is connected to an other terminal of the th gate driving circuit resistor and connected to a gate of the transistor, and a cathode of the transient suppression diode is connected to an other terminal of the second gate driving circuit resistor and an anode of the transient suppression diode is connected to a source of the coil.

In any of the above, in step , the high frequency pulse width controller is an open loop controller, and a control signal of the high frequency pulse width controller is determined by a resonance parameter of the LC series resonant circuit, wherein the control signal includes a driving voltage frequency and an on pulse width.

The beneficial effect of this application is:

according to the technical scheme, the circuit topology structure is adjusted, the open-loop conversion proportion of the converter is guaranteed to be constant under different load conditions, the circuit characteristics are equivalent to a direct current transformer model, and the direct current transformer has the advantages of being high in power density, high in load response speed, high in stability and the like. In a control circuit of the proportional converter, a negative feedback loop is not arranged, the response speed to a load is high and the stability is high only by depending on the physical characteristics of a circuit topology, the oscillation factor of the feedback loop is avoided, the phenomenon that the bridge switch is conducted by mistake to lead to a common fryer is avoided, and the reliability is high. And the protection dead zone of the half-bridge transistor is removed, and the converter almost works under the condition of full-pulse-width conduction, so that the transmitted power reaches the maximum, and the high power density is realized.

1. The symmetrical half-bridge resonance open-loop direct-current proportional converter has high power density, the LC series resonance frequency is the same as the switching frequency through parameter adjustment, the resonance current is a sine wave with the same phase and frequency as the switching waveform, soft switching of two transistors of a primary half bridge and four transistors of a secondary synchronous rectification in the converter is realized, the switching loss is almost zero, the switching frequency of the converter is greatly improved, the power density is improved, meanwhile, in an open-loop working mode, the protection dead zone of the half-bridge transistors is removed, the converter almost works under the condition of full pulse width conduction, the power transmitted by a transformer is maximized, and the power density is also improved in steps.

2. The load response speed is high: the open-loop direct-current proportional converter does not need isolation sampling and feedback loop compensation, load response is adjusted by means of the maximum adjusting capacity of the open-loop gain of the circuit, and the fastest load response speed under the same power conversion capacity is achieved.

3. The stability is high: the open-loop direct-current proportional converter has no negative feedback compensation network, can not generate self-oscillation under different load conditions, and has high stability.

4. The reliability is high: the open-loop direct-current proportional converter has no oscillation factor of a feedback loop, cannot cause the bridge switch to be conducted mistakenly to be communicated with a common fryer, and is high in reliability.

5. The efficiency is high: the symmetrical half-bridge resonance open-loop direct current proportional converter makes LC series resonance frequency the same with switching frequency through parameter adjustment, makes resonant current be the sine wave with switching waveform same phase and same frequency, has realized the soft switch of two transistors of elementary half-bridge and four transistors of secondary synchronous rectification in the converter, and switching loss is almost zero, and conversion efficiency is high.

It can be seen that, in the symmetrical half-bridge resonant open-loop dc proportional converter, the output voltage and the input voltage form a fixed ratio, which is equivalent to ideal dc transformer functions, and is a dc converter with high power density, fast load response speed, high stability, high reliability and high efficiency.

Drawings

The advantages of the above and/or additional aspects of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic block diagram of a symmetric half-bridge resonant open-loop dc proportional converter according to embodiments of the present application;

fig. 2 is a schematic diagram of a symmetric half-bridge resonant open-loop dc proportional converter according to embodiments of the present application;

fig. 3 is a schematic diagram of an LCT integrated magnetic element according to embodiments of the present application;

fig. 4 is a schematic diagram of a th, second, and third layer printed circuit boards of a th high frequency transformer primary planar winding, according to embodiments of the present application;

fig. 5 is a picture of an LCT integrated magnetic element according to embodiments of the present application;

FIG. 6 is a schematic diagram of an isolated drive transformer according to embodiments of the present application;

FIG. 7 is a schematic diagram of a gate divider driver circuit according to embodiments of the present application;

FIG. 8 is a diagram of the drive waveforms of a prototype circuit half-bridge transistor and a secondary in-phase synchronous rectifier transistor of a symmetric half-bridge resonant open-loop DC proportional converter drive circuit according to embodiments of the present application;

FIG. 9 is a drain-source voltage waveform, a resonant current waveform, a resonant capacitor end-of-line resonant voltage waveform according to embodiments of the present application;

fig. 10 is a connection block diagram of a symmetric half-bridge resonant open-loop dc proportional converter according to embodiments of the present application in a power supply system.

Detailed Description

In order to provide a more clear understanding of the above objects, features and advantages of the present application, the present application is described in further detail with reference to the accompanying drawings and detailed description.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

As shown in FIG. 1 and FIG. 2, the present embodiment provides symmetrical half-bridge resonant open-loop DC proportional converters, the open-loop DC proportional converter includes a symmetrical half-bridge switching circuit 100, an LC series resonant circuit, a high-frequency power transformer, a high-frequency synchronous rectification filter circuit 600, a fixed-width high-frequency driving control circuit 200 and an isolation driving transformer 300, the fixed-width high-frequency driving control circuit 200 includes a high-frequency pulse width controller and a high-frequency gate driver, an output end of the high-frequency pulse width controller is connected to an input end of the high-frequency gate driver, the high-frequency pulse width controller is used for inputting a control signal to the high-frequency gate driver, an output end of the high-frequency gate driver is connected to a primary end of the isolation driving transformer 300, the high-frequency gate driver is used for enhancing current driving capability of the control signal, a secondary end of the isolation driving transformer 300 is respectively connected to a control end of the symmetrical half-bridge switching circuit 100 and a control end of the high-frequency synchronous rectification filter circuit 600, the isolation driving transformer 300 is used for driving the symmetrical half-bridge switching circuit 100 to turn on or turn off according to the enhanced control.

Specifically, the input end of the symmetric half-bridge switching circuit 100 is connected with an external power supply direct current power supply, the output end thereof is connected with an LC series resonance circuit, the output end of the LC series resonance circuit is connected with a high-frequency power transformer, the output end of the high-frequency power transformer is connected with a high-frequency synchronous rectification circuit, and the output end of the high-frequency synchronous rectification circuit is used as the direct current output of the converter; the constant-width high-frequency control pulse voltage signal generated by the constant-width high-frequency drive control circuit 200 is sent to the input end of the isolation drive transformer 300, and the output end of the isolation drive transformer 300 is respectively sent to the symmetrical half-bridge switching circuit 100 and the transistors of the high-frequency synchronous rectification circuit, so that the function of open-loop high-frequency switching conversion is realized; the constant-width high-frequency driving control circuit 200 generates a constant-width high-frequency pulse voltage signal, sends the signal to the isolation driving transformer 300, sends the signal to the symmetrical half-bridge switching circuit 100 after being isolated by the isolation driving transformer 300, the symmetrical half-bridge switch circuit 100 is controlled by a constant-width high-frequency pulse voltage signal sent by the isolation driving transformer 300, the voltage amplitude generated by the direct-current input after switching conversion is the same as the direct-current input voltage, the pulse voltage source with the frequency pulse width the same as the constant-width high-frequency pulse voltage signal generated by the constant-width high-frequency driving control circuit 200 is connected to two ends of the pulse voltage source after the primary series connection of the LC series resonance circuit and the high-frequency power transformer, the pulse voltage output by the secondary side of the high-frequency power transformer is rectified and filtered by the high-frequency synchronous rectification circuit, the control signal of the high-frequency synchronous rectification circuit is also from the isolation driving transformer 300, and the whole symmetrical half-bridge resonance open-loop direct-current.

As shown in fig. 3, this embodiment shows implementations of the LC series resonant circuit and the high frequency power transformer, the LC series resonant circuit 400 and the high frequency power transformer 500 are composed of LCT integrated magnetics including a th high frequency transformer primary planar winding 401, a second high frequency transformer primary planar winding 402, and a high frequency transformer secondary planar winding 405, the magnetics further including a parasitic capacitance 403 and a parasitic inductance 404;

the parasitic capacitance 403 is closely coupled below the high frequency transformer primary planar winding 401 and above the second high frequency transformer primary planar winding 402.

Specifically, a high-dielectric-constant dielectric material with an adjustable thickness is added between the th high-frequency transformer primary planar winding 401 and the second high-frequency transformer primary planar winding 402 in a mixed-voltage mode to serve as the parasitic capacitor 403, the three are tightly coupled, the size of the inter-turn parasitic capacitor 403 is controlled, and the integrated design of the resonant capacitor of the sinusoidal power converter is completed.

The parasitic inductance 404 is closely coupled below the secondary planar winding 402 of the second high frequency transformer and above the secondary planar winding 405 of the high frequency transformer.

Specifically, a magnetic dielectric material with adjustable thickness is added between the primary planar winding 402 of the second high-frequency transformer and the secondary planar winding 405 of the high-frequency transformer to serve as the parasitic inductor 404, so that the size of the leakage inductance of the parasitic inductor 404 is controlled, and the integrated design of the resonant inductance of the sinusoidal power converter is completed.

In this embodiment, the th high-frequency transformer primary planar winding 401 and the second high-frequency transformer primary planar winding 402 are connected in series to serve as the primary winding of the high-frequency transformer, the high-frequency transformer secondary planar winding 405 is used as the secondary winding of the high-frequency transformer, the parasitic inductor 404 is multiplexed, and the three windings are used as the high-frequency transformer, thereby completing the integrated design of the high-frequency transformer.

The parasitic capacitance 403 and the parasitic inductance 404 constitute an LC series resonant circuit.

Specifically, the parasitic capacitor 403 is between the th high-frequency transformer primary planar winding 401 and the second high-frequency transformer primary planar winding 402, the parasitic inductor 404 is between the second high-frequency transformer primary planar winding 402 and the high-frequency transformer secondary planar winding 405, the parasitic capacitor 403 is connected in series with the th high-frequency transformer primary planar winding 401 and the second high-frequency transformer primary planar winding 402, the equivalent circuit of the parasitic inductor 404 is connected in series with the th high-frequency transformer primary planar winding and the second high-frequency transformer primary planar winding, the parasitic inductor 404 can control the coupling coefficient of the primary winding and the secondary winding, the magnetic dielectric material can be thickened to reduce the coupling coefficient, increase the leakage inductance, reduce the thickness of the magnetic dielectric material to improve the coupling coefficient, reduce the leakage inductance, and realize the control of the size of the leakage.

Through the design, a magnetic circuit is designed by using magnetic loops of ferrite magnetic elements, and the laminated structure is that a high-frequency transformer primary planar winding 401, a parasitic capacitor (high dielectric constant dielectric material) 403, a second high-frequency transformer primary planar winding 402, a parasitic inductor (magnetic dielectric material) 404 and a high-frequency transformer secondary planar winding 405 are tightly coupled from top to bottom in sequence.

The parasitic capacitor 403 and the primary winding of the high-frequency transformer are connected to the symmetrical half-bridge switching circuit 100, and the secondary winding of the high-frequency transformer is connected to the high-frequency synchronous rectification filter circuit 600, so that the LC series resonant circuit 400 and the high-frequency power transformer 500 can be replaced by the LCT integrated magnetic element.

, the high-frequency transformer primary planar winding 401 is composed of three layers of printed circuit boards, wherein a buried via interlayer transition region 408 is arranged on each printed circuit board, two adjacent layers of printed circuit boards are interconnected through the buried via interlayer transition region 408, and turns of winding printed lines are printed on each layers of printed circuit boards.

Specifically, in this embodiment, the th high-frequency transformer primary planar winding 401, the second high-frequency transformer primary planar winding 402, and the high-frequency transformer secondary planar winding 405 are interconnected by using a printed circuit board through a buried via interlayer transition region 408 on the printed circuit board, and each layer of the circuit board winding has turns.

Taking the th high-frequency transformer primary planar winding 401 as an example, as shown in fig. 4, fig. 4(a), 4(b) and 4(c) are sequentially a th layer, a second layer and a third layer of PCB windings, and the layout drawing of the PCB windings is completed by taking the section of a femto EI32/6/20 type ferrite core as a design.

In this embodiment, a board material of FR4 is used as an interlayer dielectric of the PCB winding, a material of Np0 (typical value of dielectric constant is 85) is used as a high dielectric constant dielectric material, and FPC _ C350 (relative permeability is 9 ± 20%) is used as a magneto-dielectric material.

The interconnection is realized through the transition region between buried hole layers on the printed circuit board, each layer of circuit board winding is turns, the maximum utilization of the area of the printed line occupied board is realized, the influence of the proximity effect between the windings in the printed board on the same layer is reduced, the rectangular conductor flat ratio of the printed winding is increased, the influence of the skin effect is reduced, and the effective current carrying capacity in the winding is improved, the copper foil occupied area between primary layers is estimated to be 90%, and the calculation is carried out according to a plate capacitance formula:

designed capacitance value of 17nF, epsilon₀Taking 8.86X 10-12F/m, epsilon_rTo 85, it can be calculated that: the thickness d is 36um, so in circuit debugging, Np0 customizes the thickness specification to be 36um, two specifications of 50um, can combine and adjust thickness d to adjust the resonance capacitance value.

The resonance leakage inductance is realized by a leakage inductance adjusting dielectric layer, namely the FPC C350, in the process of debugging the circuit, the FPC C350 with the thickness specification of 0.5mm and 1mm is customized, and the thickness can be combined and adjusted, so that the resonance inductance value is adjusted.

, the secondary planar winding 402 of the secondary high frequency transformer is composed of three layers of printed circuit boards, each layer of printed circuit boards is printed with turns of winding printed lines, and the winding printed lines of the th layer of printed circuit board of the secondary planar winding 402 of the secondary high frequency transformer are the same as the winding printed lines of the third layer of printed circuit board of the primary planar winding 401 of the th high frequency transformer.

Specifically, the printed lines of the last layer of the high-frequency transformer primary planar winding 401 and the th secondary winding of the second high-frequency transformer primary planar winding 402 are the same in shape, the last layer of the high-frequency transformer primary planar winding 401 is tightly attached to the parasitic capacitor (high-dielectric-constant dielectric material) 403 and is located above the parasitic capacitor (high-dielectric-constant dielectric material) 403, the th secondary winding of the second high-frequency transformer primary planar winding 402 is tightly attached below the parasitic capacitor (high-dielectric-constant dielectric material) 403, and the value of the parasitic capacitor 403 between the last layer of the high-frequency transformer primary planar winding 401 and the th secondary winding of the second high-frequency transformer primary planar winding 402 is increased through the increase of the thickness of the middle dielectric material.

, the secondary planar winding 405 of the high-frequency transformer is composed of two layers of printed circuit boards, a third buried via interlayer transition area is arranged on each printed circuit board, the two layers of printed circuit boards are connected in parallel through the third buried via interlayer transition area, turns of winding printed lines are printed on each layers of printed circuit boards, and the winding printed lines on the two layers of printed circuit boards are identical in shape.

, the magnetic element is provided with an iron core through hole 406, the magnetic element further comprises an EI-shaped iron core 407, and the EI-shaped iron core 407 passes through the iron core through hole 406 and passes through the high frequency transformer primary planar winding 401, the second high frequency transformer primary planar winding 402 and the parasitic capacitor 403.

Specifically, as shown in fig. 5, in the present embodiment, a flying magnetic EI32/6/20 type ferrite core is selected as the EI type iron core 407 for design, and specific parameters of the EI type iron core 407 are not described herein again. The position and thickness of the air gap of the EI-type iron core 407 can be adjusted to a larger extent for the leakage inductance of the primary and secondary sides of the high-frequency transformer. The coupling coefficient can be reduced and the leakage inductance can be increased by increasing the air gap of the central magnetic column. By increasing the air gaps of the magnetic columns on the two sides, the excitation inductance and the leakage inductance of the transformer can be synchronously reduced under the condition of keeping the coupling coefficient unchanged. For an LC sinusoidal power converter requiring wide temperature range operation, the full passage of the magnetic circuit through the EI-type iron core 407 results in a large variation in inductance, and the variation in leakage inductance is reduced by increasing the thickness of the air gap.

Therefore, magnetic loops are used for integrally designing a resonant capacitor, a resonant inductor and a high-frequency transformer, the size control of turn-to-turn parasitic capacitance is realized by adding a thickness-adjustable high-dielectric-constant dielectric material layer between turns of a primary planar winding of the high-frequency transformer, the integrated design of the resonant capacitor is completed, the size control of leakage inductance is realized by adding a thickness-adjustable magnetic dielectric material layer between primary and secondary windings of the high-frequency transformer, the integrated design of the resonant inductor is completed, the size of an LCT element is greatly reduced, the parasitic parameters of the LCT element are utilized, the power density of a sinusoidal power converter is improved, and the power density of the LCT integrated magnetic element in the embodiment is improved to 270W/cubic inch from 200W/cubic inch compared with the combination of a traditional LC resonant circuit and the high-frequency transformer through calculation of the power density.

The embodiment also shows an implementation manner of kinds of fixed-width high-frequency driving control circuits, which comprise a high-frequency pulse width controller 1 and a high-frequency gate driver 2, wherein the output end of the high-frequency pulse width controller 1 is connected to the input end of the high-frequency gate driver 2, and the high-frequency pulse width controller 1 is used for inputting a control signal to the high-frequency gate driver 2;

specifically, the high frequency pulse width controller 1 includes a clock oscillator, a flip-flop and a logic circuit, and a control signal with constant frequency and constant width can be generated by means of a conventional technique in the prior art.

Preferably, the high-frequency pulse width controller 1 is an open-loop controller, and the driving voltage frequency and the conducting pulse width of the high-frequency pulse width controller 1 are determined by the resonance parameters of the LC series-symmetric half-bridge switching circuit 8. The set driving voltage frequency and the conduction pulse width are kept constant, the pulse width is fully conducted except for a protection dead zone for preventing the transistors from being in common, namely the duty ratio of the conduction pulse width is 49%.

The high frequency pulse width controller 1 is a high frequency pulse width controller with a frequency of 750 kHz.

The output end of the high-frequency gate driver 2 is connected to the primary end of the isolation driving transformer 3, in this embodiment, a driving integrated circuit such as UCC27714 is provided, and the high-frequency gate driver 2 is used for enhancing the current driving capability of the control signal through the totem pole of the driving integrated circuit;

the high frequency gate driver 2 is a high frequency gate driver with a frequency of 750 kHz.

The present embodiment also shows implementations of the isolation driving transformer, wherein six coils are disposed at the secondary end of the isolation driving transformer 300, the coil 32 and the second coil 33 are connected to the driving circuit, the third coil 34, the fourth coil 35, the fifth coil 36 and the sixth coil 37 are connected to the second driving circuit, wherein the coil 32, the third coil 34 and the fifth coil 36 are dotted terminals, the second coil 33, the fourth coil 35 and the sixth coil 37 are second dotted terminals, and the dotted terminals and the second dotted terminals are interleaved in phase.

Specifically, as shown in fig. 6, the isolation driving transformer completes the timing control of six interleaved driving signals through the design of the same-name end, and realizes the switching control of two half-bridge transistors in a symmetrical half-bridge switching circuit and the synchronous rectification control of four synchronous rectification transistors in a high-frequency synchronous rectification filter circuit.

The primary side 31 of the isolation driving transformer is connected to the high-frequency gate driver, receives the control signal Sp with enhanced current driving capability, the positive ends of the th coil 32, the third coil 34 and the fifth coil 36 on the secondary side of the isolation driving transformer are homonymous ends, the generation signals Ss1, Ss3 and Ss5 are in phase with the control signal Sp, the negative ends of the second coil 33, the fourth coil 35 and the sixth coil 37 are homonymous ends, and the generation signals Ss2, Ss4 and Ss6 are 180 degrees different in phase from the control signal Sp, namely, the phases are staggered.

, the symmetrical half-bridge switching circuit 100 is a symmetrical half-bridge switching circuit 100 composed of two half-bridge transistors (101, 102), two voltage-sharing capacitors (103, 104), two voltage-sharing resistors (105, 106) and a high-frequency power transformer, the th driving circuit includes two th gate voltage-dividing driving circuits, and the th coil 32 and the second coil 33 are sequentially connected to the two th gate voltage-dividing driving circuits and respectively connected to the gates of the two half-bridge transistors connected in series in the symmetrical half-bridge switching circuit 100.

Specifically, the signals Ss1 and Ss2 correspond to the th driving voltage signals S1 and S2, and are respectively transmitted to the gates of the half-

bridge transistors

101 and 102 through the two th gate voltage dividing driving circuits, and the signals Ss1 and Ss2 are electrically isolated and are staggered in phase.

Further , the high frequency synchronous rectification filter circuit 600 is a synchronous high frequency synchronous rectification filter circuit 600 composed of four synchronous rectification transistors (610, 611, 612, 613) and a filter capacitor 614, the four synchronous rectification transistors are connected to the secondary side of the high frequency power transformer, the second driving circuit includes four second gate voltage division driving circuits, and the third coil 34, the fourth coil 35, the fifth coil 36 and the sixth coil 37 are connected to the gates of the four synchronous rectification transistors in the synchronous high frequency synchronous rectification filter circuit 600 through the four second gate voltage division driving circuits in sequence.

Specifically, the signals Ss3, Ss4, Ss5 and Ss6 correspond to the second driving voltage signals Sa1, Sa2, Sa3 and Sa4 in sequence, and are transmitted to the gates of the

synchronous rectification transistors

610, 611, 612 and 613 respectively through four paths of second gate voltage division driving circuits, the signals Ss3, Ss4, Ss5 and Ss6 are electrically isolated, and the signals Ss3 and Ss5 are staggered in phase with the signals Ss4 and Ss 6.

, as shown in FIG. 7, the gate voltage-dividing driving circuit and the second gate voltage-dividing driving circuit are identical in structure, the 0 gate voltage-dividing driving circuit includes four HF diodes, a transient suppression diode 48 and three gate driving circuit resistors, the 1 th HF diode 42 has its cathode connected to the anode of the second HF diode 44 and connected to the positive terminal of the coil, the th HF diode 42 has its anode connected to the terminal of the gate driving circuit resistor 43 of the th, the second HF diode 44, the third HF diode 45 and the fourth HF diode 46 are connected in series in phase, the cathode of the fourth HF diode 46 is connected to the terminal of the second gate driving circuit resistor 47, the other terminal of the second gate driving circuit resistor 47 is connected to the other terminal of the gate driving circuit resistor 43 of the and connected to the half-bridge of the transistors 410 (i.e., the synchronous rectifier transistors 610, 611, 612, 613 and 102), the transient suppression diode 48 and the third HF diode resistor 48 are connected in parallel to the cathode of the coil, the transient suppression diode 48 and connected to the source of the transient driving circuit resistor 410 and connected to the source of the second gate driving circuit resistor .

Specifically, the number of two high-frequency diodes in the th gate voltage division driving circuit can be determined according to actual requirements, and the th gate voltage division driving circuit enables the on-state voltage of the transistor 410 to be lower than the off-state voltage by two diode drops, for example, for the driving of a GS66508 type gallium nitride transistor, the forward withstand voltage is 7V, the reverse withstand voltage is-10V, and the positive and negative voltages between drive signals and the gate source are different, in this embodiment, the positive voltage is set to be 5V, the negative voltage is greater than the positive voltage by two diode drops, namely, the negative voltage is-6.2V, so that the saturated on and the fast off of the transistor 410 are realized, and the tolerance design of the voltage between the gate sources is ensured.

Adjusting the second gate driving circuit resistor 37 can change the conducting front edge of the transistor 410 if the gate-source parasitic capacitance of the transistor 410 is C_gsThe resistance of the second gate driving circuit resistor 47 is R_gThe positive voltage of the signal SsX (X ═ 1,2, … 6) is v_gThe gate-source voltage of the transistor 410 is v₀Then, there is the following relationship in the rising process because the third gate driving circuit resistor 49 has a larger resistance value, and the voltage division effect of the second gate driving circuit resistor 47 and the third gate driving circuit resistor 49 is neglected.

In the formula, v_thTo turn on the threshold voltage of the transistor, τ is the transistor turn on front time.

The resistance of the second gate driving circuit resistor 47 can be adjusted to be R_gThe size of the transistor is controlled to realize tau, when tau is too small, the ringing of a driving signal of the transistor is serious, and when tau is too large, the transistor is used410 are too large in switching losses.

Similarly, the control of the turned-off trailing edge of the transistor can be realized by adjusting the resistance of the th gate driving circuit resistor 43.

In order to verify the effectiveness of the control of the driving circuit in the embodiment on the symmetric half-bridge resonant open-loop dc proportional converter, LM5035A is used as the high-frequency pulse width controller, UCC277101 is used as the high-frequency gate driver, the slope compensation and feedback pins are connected to a fixed level, so that the high-frequency pulse width controller LM5035A is in an open-loop operating mode, the output pulse width is maximum, an external resistor is adjusted to obtain a suitable dead time, the output driving waveform of the high-frequency pulse width controller LM5035A is connected to the high-frequency gate driver UCC27714, the high-frequency gate driver is isolated by an isolation driving transformer at the later stage, a magnetic core made of a femto 3F4 material is used as an iron core of the isolation driving transformer, and the output of the high-frequency gate driver uc.

Through the circuit prototype test of the embodiment, waveforms of the signals Ss1 and Ss3 can be measured and obtained as shown in fig. 8, the signals Ss1 and Ss3 sequentially correspond to the waveforms a and B in fig. 8, and the waveform A, B is basically as can be obtained through analysis of the waveform A, B, that is, switching of a primary side half bridge transistor and synchronous rectification of a secondary side full bridge transistor in the symmetrical half bridge resonant open loop dc proportional converter can be realized through the driving circuit of the symmetrical half bridge resonant open loop dc proportional converter in the embodiment.

Further , the high frequency pulse width controller is an open loop controller, and the control signal of the high frequency pulse width controller is determined by the resonance parameter of the LC series resonant circuit, wherein the control signal includes a driving voltage frequency and an on pulse width.

This embodiment further shows driving methods of a symmetric half-bridge resonant open-loop dc proportional converter, which are suitable for driving the driving circuit of the symmetric half-bridge resonant open-loop dc proportional converter in the above embodiments, and the method includes:

step 1, determining the switching frequency of a driving circuit according to the resonance angular frequency of an LC series-connection symmetric half-bridge switching circuit;

and 2, sending a transistor conduction instruction to the driving circuit according to the switching frequency, wherein the transistor conduction instruction is used for controlling the transistor in the driving circuit to be conducted or disconnected.

As shown in fig. 9, the switching frequency is set to 451kHz, a curve 810 in fig. 9 is a drain-source waveform of a transistor on a half-bridge transistor, i.e., a drain-voltage waveform with the source of the transistor as a reference point, a curve 820 is a resonant current waveform, and a curve 830 is a resonant voltage waveform across the resonant capacitor. As can be seen from fig. 9, the waveform of the operating current is close to a sine wave, the switching crossover is negligible, the soft switching characteristic is good, and the actual effect of the circuit of the embodiment is verified.

As shown in fig. 10, with the continuous development of the power supply architecture, most of the current power supply systems are front-end modules that perform rectification filtering and active power factor correction of an ac input power, dc powers with relatively high stable voltage are output, and the requirements of load points on the quality of the power supply are higher and higher, and there are many load-point voltage regulators with different power supply voltages, but the input voltage is generally low, and in this usage context, the requirement of the intermediate-stage isolation proportional converter for the precision of voltage stabilization is properly reduced.

The AC is input into a front-end power supply 21, the secondary DC bus power supply with relatively stable voltage generated by the front-end filtering and active power factor correction is input into a symmetrical half-bridge resonance open-loop DC proportional converter 22, the secondary DC bus power supply is sent to n load point voltage regulators 23 after the proportional voltage reduction and the electrical isolation are completed, the secondary DC bus power supply is sent to a load 24 after the final voltage stabilization of the load point voltage regulators, and the connection relationship is the practical application of the invention in a power supply system.

The symmetrical half-bridge resonance open-loop direct-current proportional converter is connected in the circuit mode, the working characteristic that the voltage gain is constant under different load conditions is determined through a large signal transfer function of a circuit topological structure, the stability of the output voltage of the open-loop proportional converter under different load conditions is guaranteed, a negative feedback loop does not exist, the response speed to a load is high, the stability is high, the oscillation factor of the feedback loop does not exist, the bridge switch cannot be conducted mistakenly to share the explosion machine due to the fact that the oscillation factor of the feedback loop does not exist, the reliability is high, the protection dead zone of a half-bridge transistor is removed, the converter almost works under the condition of full-pulse-width conduction, the transmitted power reaches the maximum, and high power density is achieved.

The technical scheme of the application is explained in detail in the above with reference to the accompanying drawings, and the application provides symmetrical half-bridge resonant open-loop direct-current proportional converters, wherein each open-loop direct-current proportional converter comprises a symmetrical half-bridge switching circuit, an LC series resonant circuit, a high-frequency power transformer, a high-frequency synchronous rectification filter circuit and an open-loop direct-current proportional converter which are sequentially connected, and further comprises a fixed-width high-frequency driving control circuit and an isolation driving transformer, wherein the fixed-width high-frequency driving control circuit comprises a high-frequency pulse width controller and a high-frequency gate driver, an output end of the high-frequency pulse width controller is connected to an input end of the high-frequency gate driver, the high-frequency pulse width controller is used for inputting a control signal to the high-frequency gate driver, an output end of the high-frequency gate driver is connected to a primary end of the isolation driving transformer, the high-frequency gate driver is used for enhancing the current driving capability of the control signal, a secondary end of the isolation driving transformer is respectively connected to a control end of the symmetrical half-bridge switching circuit and a control end of the high-frequency synchronous rectification filter circuit, the isolation driving transformer is used for driving the on or off of the transistors in the symmetrical half-bridge switching circuit according to the enhanced control signal, and for preventing the topology of the bridge synchronous rectification filter circuit from being falsely connected to.

The steps in the present application may be sequentially adjusted, combined, and subtracted according to actual requirements.

The units in the device can be merged, divided and deleted according to actual requirements.

Although the present application has been disclosed in detail with reference to the accompanying drawings, it is to be understood that such description is merely illustrative and not restrictive of the application of the present application. The scope of the present application is defined by the appended claims and may include various modifications, adaptations, and equivalents of the invention without departing from the scope and spirit of the application.

Claims

The symmetrical half-bridge resonance open-loop direct-current proportional converter is characterized by comprising a symmetrical half-bridge switching circuit, an LC series resonance circuit, a high-frequency power transformer and a high-frequency synchronous rectification filter circuit which are sequentially connected, a fixed-width high-frequency drive control circuit and an isolation drive transformer;

the fixed-width high-frequency driving control circuit comprises a high-frequency pulse width controller and a high-frequency grid driver, wherein the output end of the high-frequency pulse width controller is connected to the input end of the high-frequency grid driver, the high-frequency pulse width controller is used for inputting a control signal to the high-frequency grid driver, the output end of the high-frequency grid driver is connected to the primary end of the isolation driving transformer, and the high-frequency grid driver is used for enhancing the current driving capability of the control signal;

the secondary end of the isolation driving transformer is respectively connected with the control end of the symmetrical half-bridge switch circuit and the control end of the high-frequency synchronous rectification filter circuit, and the isolation driving transformer is used for driving the on-off of the half-bridge transistor in the symmetrical half-bridge switch circuit and driving the on-off of the full-bridge synchronous rectification transistor in the high-frequency synchronous rectification filter circuit according to the control signal after enhancement.
2. The symmetrical half-bridge resonant open-loop DC proportional converter of claim 1, wherein the LC series resonant circuit and the high frequency power transformer are comprised of LCT integrated magnetics comprising th high frequency transformer primary planar winding, second high frequency transformer primary planar winding and high frequency transformer secondary planar winding, the magnetics further comprising parasitic capacitance and parasitic inductance;

the parasitic capacitance is closely coupled below the th high-frequency transformer primary planar winding and above the second high-frequency transformer primary planar winding;

the parasitic inductance is closely coupled below the primary planar winding of the second high-frequency transformer and above the secondary planar winding of the high-frequency transformer,

and the parasitic capacitor and the parasitic inductor form an LC series resonance circuit.
3. The symmetrical half-bridge resonant open-loop dc proportional converter as claimed in claim 2, wherein the th high frequency transformer primary planar winding is composed of three layers of printed circuit boards, the printed circuit boards are provided with th buried via interlayer transition regions, two adjacent layers of printed circuit boards are interconnected through the th buried via interlayer transition regions, each layers of printed circuit boards are printed with turns of winding tracks.
4. The symmetric half-bridge resonant open-loop dc proportional converter as claimed in claim 3, wherein the primary planar winding of the second high frequency transformer is composed of three layers of printed circuit boards, each layers of printed circuit boards having turns of winding tracks printed thereon, and the winding tracks of the th layer of printed circuit board of the primary planar winding of the second high frequency transformer have the same shape as the winding tracks of the third layer of printed circuit board of the primary planar winding of the high frequency transformer.
5. The symmetrical half-bridge resonant open-loop dc-to-dc ratio converter according to claim 4, wherein the secondary planar winding of the high frequency transformer is composed of two layers of printed circuit boards, the printed circuit boards are provided with a third buried via interlayer transition region, the two layers of printed circuit boards are connected in parallel through the third buried via interlayer transition region, each layers of printed circuit boards are printed with turns of winding tracks, and the winding tracks on the two layers of printed circuit boards are identical in shape.
6. The symmetric half-bridge resonant open-loop dc proportional converter of claim 1, wherein the secondary side of the isolated drive transformer is provided with six coils;

an th coil and a second coil are connected to the th driving circuit, and a third coil, a fourth coil, a fifth coil and a sixth coil are connected to the second driving circuit, wherein the th coil, the third coil and the fifth coil are th dotted terminals, the second coil, the fourth coil and the sixth coil are second dotted terminals, and the th dotted terminals and the second dotted terminals are staggered in phase.
7. The symmetrical half-bridge resonant open-loop DC proportional converter as claimed in claim 6, wherein the symmetrical half-bridge switching circuit is a symmetrical half-bridge switching circuit consisting of two half-bridge transistors, two voltage-sharing capacitors, two voltage-sharing resistors and a high-frequency power transformer, wherein the th driving circuit comprises two th grid voltage-dividing driving circuits;

the th coil and the second coil sequentially pass through the th grid voltage division driving circuit in two ways and are respectively connected with the grids of two half-bridge transistors which are connected in series in the symmetrical half-bridge switching circuit.
8. The symmetrical half-bridge resonant open-loop dc proportional converter according to claim 7, wherein the high frequency synchronous rectifying-filtering circuit is a synchronous high frequency synchronous rectifying-filtering circuit composed of four synchronous rectifying transistors and a filtering capacitor, the four synchronous rectifying transistors being connected to the secondary side of the high frequency power transformer, wherein the second driving circuit comprises: four second grid voltage division driving circuits;

the third coil, the fourth coil, the fifth coil and the sixth coil are sequentially connected with four paths of second grid voltage division driving circuits and respectively connected with the grids of four synchronous rectification transistors in the synchronous high-frequency synchronous rectification filter circuit.
9. The symmetrical half-bridge resonant open-loop DC-to-DC proportional converter of claim 8, wherein the th gate divider driver circuit and the second gate divider driver circuit are identical in structure, the th gate divider driver circuit comprises four high frequency diodes, a transient suppression diode and three gate driver circuit resistors, wherein,

the cathode of the th high-frequency diode is connected with the anode of the second high-frequency diode and then connected with the positive end of the coil, and the anode of the th high-frequency diode is connected with the end of the th gate drive circuit resistor;

after the second high-frequency diode, the third high-frequency diode and the fourth high-frequency diode are connected in series in the same phase, the cathode of the fourth high-frequency diode is connected to the end of the second gate driving circuit resistor, and the other end of the second gate driving circuit resistor is connected to the other end of the gate driving circuit resistor and is connected to the gate of the transistor;

after the transient suppression diode and the third gate drive circuit resistor are connected in parallel, the cathode of the transient suppression diode is connected to the other terminal of the second gate drive circuit resistor, and the anode of the transient suppression diode is connected to the negative terminal of the coil and to the source of the transistor.
10. The symmetric half-bridge resonant open-loop dc-to-dc proportional converter of claim 1, wherein the high frequency pulse width controller is an open-loop controller, the control signal of the high frequency pulse width controller being determined by a resonant parameter of the LC series resonant circuit, wherein the control signal comprises a drive voltage frequency and a conduction pulse width.