CN220935023U - Power conversion system - Google Patents
Power conversion system Download PDFInfo
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- CN220935023U CN220935023U CN202322668244.4U CN202322668244U CN220935023U CN 220935023 U CN220935023 U CN 220935023U CN 202322668244 U CN202322668244 U CN 202322668244U CN 220935023 U CN220935023 U CN 220935023U
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Abstract
The utility model discloses a power supply conversion system which comprises a resonant capacitor C r, a transformer, power switching devices S1, S2, Q1 and Q2, wherein the power switching devices S1, S2 and Q1 are connected in series and connected between an input positive electrode interface and an input negative electrode interface in parallel, and one end of the power switching device Q2 is connected with the input negative electrode interface; the transformer comprises a primary winding T 1 and two secondary windings T 21、T22 with the same number of turns, wherein one end of a resonant capacitor C r and the primary winding T 1 are connected in series and then connected between power switch pieces S1 and S2, and the other end of the resonant capacitor C r is connected to the non-grounding end of a power switch piece Q2; one end of the two secondary windings T 21、T22 are connected in series and then connected between the power switching devices S2 and Q1, and the other end of the two secondary windings T 21、T22 is connected to the non-grounding end of the power switching device Q2; an output positive electrode port is connected to a connecting line between the two secondary windings T 21、T22, and an output negative electrode port is connected with an input negative electrode port through a connecting line.
Description
Technical Field
The present utility model relates to a power conversion system.
Background
The conventional buck high-current output dc power conversion system generally employs a hybrid switched capacitor conversion circuit, as shown in fig. 1 (from CN112491269 a power conversion system) and fig. 2 (from CN111416516 a hybrid switched capacitor converter). The hybrid switched capacitor conversion circuit has the advantages of small switching loss, small current stress of a switching tube and the like, so that the converter can work at a higher switching frequency (hundreds of kilohertz to several megahertz), thereby remarkably reducing the volume of a magnetic element of the converter and greatly improving the power density of the converter.
However, for the circuit of fig. 1, it can only fix the input-output voltage transformation ratio to 4:1, thereby limiting its application range. In fact, on-board bus converters of modern data center microprocessors have a trend towards large voltage transformation ratios of 8:1, 10:1 and the like, and bus converters with 4:1 fixed transformation ratios are difficult to meet voltage transformation requirements; for the circuit of fig. 2, although it can realize flexible voltage transformation ratio by changing the turns ratio of the transformer, the transformer of the circuit has two primary windings and two secondary windings, the complex multi-winding coupling relationship and the high-frequency current loop bring great challenges to the design of the transformer, and the improvement of the efficiency and the power density of the transformer is limited to a certain extent.
Therefore, how to develop a power conversion system capable of improving the above prior art is an urgent need.
Disclosure of utility model
The technical problems to be solved by the utility model are as follows: the power conversion system can flexibly realize the 1 DC voltage transformation ratio of X, wherein X can be any integer greater than or equal to 5, has the technical advantages of low switching loss and low conduction loss, and is suitable for being applied to data centers, bus converters in vehicles and the like.
In order to solve the technical problems, the utility model adopts the following technical scheme: the device comprises an input positive electrode interface, an input negative electrode interface, an output positive electrode interface, an output negative electrode interface, a resonant capacitor C r and a transformer; an output capacitor is arranged between the output positive electrode interface and the output negative electrode interface, and the power switch piece S1, the power switch device S2 and the power switch device Q1 are connected in series in sequence and then are connected between the input positive electrode interface and the input negative electrode interface; the transformer comprises a primary winding T 1 and two secondary windings T 21、T22, the turns of the two secondary windings are the same, one end of the resonant capacitor C r and the primary winding T 1 which are connected in series is connected between the power switch pieces S1 and S2, and the other end of the resonant capacitor C r and the primary winding T 1 are connected to the non-grounding end of the power switch piece Q2; the same-name end of the primary winding T 1 of the transformer is positioned between the power switch piece S1 and the power switch piece S2; the same-name end of one transformer secondary winding T 21 is connected with the different-name end of the other transformer secondary winding T 22, the different-name end of the transformer secondary winding T 21 is connected between the power switch piece S2 and the power switch piece Q1, the same-name end of the other transformer secondary winding T 22 is connected to the non-grounding end of the power switch piece Q2, and the other end of the power switch piece Q2 is connected with an input negative electrode interface; an output positive electrode port is connected to a connecting line between the two secondary windings T 21、T22; the input capacitor is connected between the input positive electrode interface and the input negative electrode interface or the output positive electrode port; the output negative electrode port is connected with the input negative electrode port through a wiring, and a grounding wire is also connected with the wiring between the output negative electrode port and the input negative electrode port.
As a preferable scheme, the power switch components S1 and Q1 are controlled by the first control signal and turned on and off simultaneously, the power switch components S2 and Q2 are controlled by the second control signal and turned on and off simultaneously, and the first control signal and the second control signal are 180 degrees out of phase.
As a preferred solution, the primary winding T 1 and the two secondary windings T 21、T22 are wound on the same core leg.
The beneficial effects of the utility model are as follows:
according to the technical scheme, the X-1 direct-current voltage transformation ratio can be flexibly realized, wherein X can be any integer greater than or equal to 5, so that the technical scheme has obvious advantages in the application fields of the 48V bus converter of the data center and the vehicle-mounted 48V bus converter. The 8:1 voltage change bit is suitable for a 48V data center microprocessor on-board bus converter based on a 6V bus architecture at present.
The transformer of the technical scheme only comprises one primary winding and two secondary windings, and compared with the prior art, the technical scheme has the advantages of small number of windings and simple coupling mode; meanwhile, the working mode and the high-frequency current loop of the transformer are simple, so that the design difficulty of the transformer of the core device of the transformer can be remarkably reduced, and the high efficiency and the high power density of the power supply can be realized more easily.
The power conversion system controls the power switch to act, and the resonance capacitor Cr resonates with the resonance inductor of the transformer, so that soft switching operation of all the power switch is realized, and particularly, zero-voltage switching can be realized by the power switch S1 and S2, so that no switching loss exists; the turn-off loss is greatly reduced. The power switch components Q1 and Q2 can realize zero-current on and zero-current off, and no switching loss exists.
Since all power switching elements operate as soft switches, the switching frequency of the converter can be increased to a high frequency range (hundreds of kilohertz to several megahertz), thereby significantly reducing the volume of the magnetic element and achieving higher power densities.
Drawings
FIG. 1 is a prior art hybrid switched capacitor converter circuit;
FIG. 2 is a schematic diagram of another conventional hybrid switched capacitor converter circuit;
FIG. 3 is a schematic diagram of a circuit topology of the present power conversion system;
FIG. 4 is a schematic diagram of an equivalent circuit of the present power conversion system;
FIG. 5 is a schematic diagram of a positive half-cycle equivalent circuit of the present power conversion system;
FIG. 6 is a schematic diagram of a negative half-cycle equivalent circuit of the present power conversion system;
FIG. 7 is a waveform diagram of the present power conversion system;
FIG. 8 is a schematic circuit diagram of embodiment 2 of the present power conversion system;
FIG. 9 is a schematic circuit diagram of a power conversion system according to embodiment 3 of the present invention;
FIG. 10 is a schematic circuit diagram of a power conversion system according to embodiment 4 of the present invention;
Detailed Description
Specific embodiments of the present utility model are described in detail below with reference to the accompanying drawings.
Embodiment 1 as shown in fig. 3, a power conversion system includes an input positive electrode interface V in +, an input negative electrode interface V in -, an output positive electrode interface V o +, an output negative electrode interface V o -, a resonance capacitor Cr, a transformer, a power switch device S1, a power switch device S2, a power switch device Q1, and a power switch device Q2, wherein an input capacitor Cin is disposed between the input positive electrode interface V in + and the input negative electrode interface V in -; an output capacitor Co is arranged between the output positive electrode interface V o and the output negative electrode interface V o;
The transformer comprises a primary winding T 1 and two secondary windings T 21、T22, the number of turns of the two secondary windings is the same, one end of a resonant capacitor C r and the primary winding T 1 are connected in series and then connected between a power switch piece S1 and a power switch piece S2, and the other end of the resonant capacitor C r is connected to a non-grounding end of the power switch piece Q2; the same-name end of the primary winding T 1 of the transformer is positioned between the power switch piece S1 and the power switch piece S2; the same-name end of one transformer secondary winding T 21 is connected with the different-name end of the other transformer secondary winding T 22, the different-name end of the transformer secondary winding T 21 is connected between the power switch piece S2 and the power switch piece Q1, the same-name end of the other transformer secondary winding T 22 is connected to the non-grounding end of the power switch piece Q2, and the other end of the power switch piece Q2 is connected with an input negative electrode interface;
The power switch piece S1 and the power switch piece S2 are Si MOSFETs or GaN HEMTs or SiC MOSFETs.
An output positive electrode port is connected to a connecting line between the two secondary windings T 21、T22, an output negative electrode port is connected with an input negative electrode port through a connecting line, and a grounding wire is also connected to the connecting line between the output negative electrode port and the input negative electrode port. The primary winding T 1 and the two secondary windings T 21、T22 are wound on the same core leg.
The power switch piece performs periodic action according to the switching period, and the resonance capacitor and the resonance inductor generate resonance by controlling the on or off of the power switch piece. The power switch piece S1 and the power switch piece Q1 are controlled by a control signal I to be simultaneously turned on and turned off, the power switch piece S2 and the power switch piece Q2 are controlled by a control signal II to be simultaneously turned on and turned off, and the control signal I and the control signal II are 180 degrees out of phase.
Fig. 4 is an equivalent circuit of fig. 3, in which a transformer consisting of a primary winding T 1, a secondary winding T 21, and a secondary winding T 22 is equivalent to an ideal transformer with a turns ratio of N 1:N2:N2, an excitation inductance L m converted to the primary, and a leakage inductance L k converted to the primary.
By controlling the power switching element to operate, the resonant capacitor C r resonates with the resonant inductor L r, so that the power switching element can realize soft switching operation, wherein the resonant inductor can be, for example, but not limited to, leakage inductance of a transformer and parasitic inductance of a wire.
The working principle of the power supply conversion system at the stage t 0-t 1 is specifically as follows:
As shown in fig. 5 and 7, at time t 0, the power switch S1 and the power switch Q1 are turned on, the circuit operates in a positive half-period of resonance, and the circuit resonant frequency f r is shown in formula (1):
wherein Cr is a resonance capacitor; lr is the resonant inductance;
The switching frequency f s of the converter is equal to the resonant frequency f r, namely f s＝fr, the series impedance of the resonant capacitor and the resonant inductor in the resonant state is 0, and according to kirchhoff's voltage law, let N be N 1/N2, the voltage becomes as shown in formula (2):
wherein V o is the output voltage; v in is the input voltage; n 1 is the number of turns of the primary winding of the transformer; n 2 is the number of turns of the secondary winding of the transformer. According to the formula (2), the circuit can realize the 1-to-1 transformation ratio of the input and output voltage X, wherein X is any integer which is larger than or equal to 5.
The exciting inductance current increases linearly, and the current change rate is shown as a formula (3):
Wherein i Lm is exciting current; l m is an excitation inductor;
The current of the secondary winding T 22 of the transformer is equal to the primary resonance current, namely i w1＝ip, and the current i w2 of the secondary winding T 21 of the transformer can be obtained according to magnetomotive force balance of the transformer, as shown in formula (4):
iw2＝ip+nis＝iw1+nis (4)
Wherein i p is primary side resonance current; i w2 is the current of the secondary winding T 21 of the transformer; i s is the secondary side resonant current;
At time t 1, power switch S1 and power switch Q1 are turned off. As the current i w2 of the secondary winding T 21 of the transformer resonates to 0, the power switch piece Q1 realizes zero current turn-off; according to formulas (3) and (4), the off current Ip of the power switch S1 is:
Where fs is the switching frequency.
The working principle of the power conversion system at the stage t 1-t 2 is as follows:
After the power switch S1 and the power switch Q1 are turned off at time t1, the circuit operates in a dead zone phase from t1 to t2, and the duration is defined as td. In general, the dead time td is far smaller than the switching period of the circuit operation, and the excitation current and the resonance current in the dead time stage are approximately considered to be unchanged; the constant current source I p charges the output capacitor of the power switch piece S1, discharges the output capacitor of the power switch piece S2, and the body diode of the power switch piece S2 conducts the follow current after the charge and discharge are completed, so that the bridge arm voltage v AB realizes smooth phase change. After the process is finished, the power switch S2 at time t 2 realizes zero-voltage switching on, and the power switch Q2 at time realizes zero-current switching on.
The switching frequency fs, the dead time td and the excitation inductance value Lm can be reasonably designed, so that the power switch piece S2 realizes zero-voltage switching-on, and the power switch piece Q2 realizes zero-current switching-on.
The working principle of the power conversion system in the t 2-t 3 stage is symmetrical to that of the t 0-t 1 stage, and the same analysis can be used for obtaining: the power switch piece S2 and the power switch piece Q2 are turned on at the time t2, the circuit operates in a resonance state, and the resonance frequency is shown in the formula (1). the power switch piece Q2 realizes zero current turn-off at the time t 3; the power switch S2 turns off the current level Ip as shown in equation (5).
The working principle of the power conversion system in the t 3-t 4 stage is symmetrical to that of the t 1-t 2 stage, and the same analysis can be used for obtaining: the power switch piece S2 and the power switch piece Q2 are turned off at the moment t3, the circuit operates in a dead zone stage from t3 to t4, and in general, the dead zone time td is far smaller than the switching period of the circuit operation, and the excitation current and the resonance current in the dead zone stage are approximately considered to be unchanged; the constant current source I p charges the output capacitor of the power switch piece S2, discharges the output capacitor of the power switch piece S1, and the body diode of the power switch piece S1 conducts follow current after the charge and discharge are completed, so that the bridge arm voltage v AB realizes smooth phase change. After the process is finished, the power switch piece S1 realizes zero-voltage switching-on at the time t 3, and the power switch piece Q1 realizes zero-current switching-on.
The voltage and current stress analysis of the power switch part of the power conversion system is as follows:
the transformer winding current in fig. 7 is analyzed by adopting a fundamental wave equivalent model, and the following steps are obtained:
Where i w,p1、iw,p2 is the peak transformer secondary winding current, as indicated in fig. 7; i o,dc is the output current average value. The current stress of each power switch element can be deduced from the equation (6).
The following table is a summary of the characteristics of the power switch components of the power conversion system:
Example 2 is shown in fig. 8, which differs from example 1 in that: the power switches Q1 and Q2 are diodes.
Example 3 is shown in fig. 9, which differs from example 1 in that: an external inductance connection module A and an external inductance connection module B are respectively arranged at two ends of the primary winding T 1, and an external inductance connection module C and an inductance connection module D are respectively arranged at the end parts, far away from the secondary winding T 21 and the secondary winding T 22.
Example 4 is shown in fig. 10, which differs from example 1 in that: one end of the input capacitor C in is connected between the input positive electrode interface and the output positive electrode interface in a bridging way, and the capacitor is connected with the output capacitor in series to serve as the input capacitor of the power conversion system.
In the embodiments described above, the switching frequency of the converter is equal to the resonant frequency, and in other embodiments, the corresponding power switch may be turned off when the secondary winding current of the transformer does not resonate to 0. Because the capacitance of the resonant capacitor Cr is larger and the inductance of the resonant inductor Lr is smaller, the power device switch is not turned off with zero current, but the turn-off loss is smaller and can be ignored. Typically, the switching frequency does not exceed twice the resonant frequency.
The above-described embodiments are merely illustrative of the principles and functions of the present utility model, and some of the practical examples, not intended to limit the utility model; it should be noted that modifications and improvements can be made by those skilled in the art without departing from the inventive concept, and these are all within the scope of the present utility model.
Claims (3)
1. A power conversion system comprises an input positive electrode interface, an input negative electrode interface, an output positive electrode interface, an output negative electrode interface, a resonant capacitor C r and a transformer; an output capacitor is arranged between the output positive electrode interface and the output negative electrode interface, and is characterized in that: the power switch piece S1, the power switch device S2 and the power switch device Q1 are sequentially connected in series and then connected between an input positive electrode interface and an input negative electrode interface; the transformer comprises a primary winding T 1 and two secondary windings T 21、T22, the turns of the two secondary windings are the same, one end of the resonant capacitor C r and the primary winding T 1 which are connected in series is connected between the power switch pieces S1 and S2, and the other end of the resonant capacitor C r and the primary winding T 1 are connected to the non-grounding end of the power switch piece Q2; the same-name end of the primary winding T 1 of the transformer is positioned between the power switch piece S1 and the power switch piece S2; the same-name end of one transformer secondary winding T 21 is connected with the different-name end of the other transformer secondary winding T 22, the different-name end of the transformer secondary winding T 21 is connected between the power switch piece S2 and the power switch piece Q1, the same-name end of the other transformer secondary winding T 22 is connected to the non-grounding end of the power switch piece Q2, and the other end of the power switch piece Q2 is connected with an input negative electrode interface; an output positive electrode port is connected to a connecting line between the two secondary windings T 21、T22; the input capacitor is connected between the input positive electrode interface and the input negative electrode interface or the output positive electrode port; the output negative electrode port is connected with the input negative electrode port through a wiring, and a grounding wire is also connected with the wiring between the output negative electrode port and the input negative electrode port.
2. A power conversion system according to claim 1, wherein: the power switch piece S1 and the power switch piece Q1 are controlled by a first control signal and are simultaneously turned on and off, the power switch piece S2 and the power switch piece Q2 are controlled by a second control signal and are simultaneously turned on and off, and the first control signal and the second control signal are 180 degrees out of phase.
3. A power conversion system according to any one of claims 1-2, wherein: the primary winding T 1 and the two secondary windings T 21、T22 are wound on the same magnetic core column.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322668244.4U CN220935023U (en) | 2023-09-28 | 2023-09-28 | Power conversion system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202322668244.4U CN220935023U (en) | 2023-09-28 | 2023-09-28 | Power conversion system |
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| CN220935023U true CN220935023U (en) | 2024-05-10 |
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| CN202322668244.4U Active CN220935023U (en) | 2023-09-28 | 2023-09-28 | Power conversion system |
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