CN212518799U

CN212518799U - Circuit for solving primary multipath parallel current sharing by utilizing magnetic circuit full coupling

Info

Publication number: CN212518799U
Application number: CN202021350092.3U
Authority: CN
Inventors: 徐艳超; 陈超飞; 李金洁; 吴飞飞; 赵耀峰; 张现民; 李维旭; 杨旭东
Original assignee: Shijiazhuang Tonghe Electronics Co Ltd
Current assignee: Shijiazhuang Tonghe Electronics Co Ltd
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2021-02-09
Anticipated expiration: 2030-07-10

Abstract

The utility model provides an utilize magnetic circuit total coupling to solve the parallelly connected circuit that flow equalizes of elementary multichannel, can realize the direct parallelly connected autonomic flow equalizing of multichannel to the multichannel can use one set of drive circuit, greatly simplifies circuit topology, optimizes inductance and transformer design method, does not increase any other hardware costs. The method is realized by designing a direct parallel multi-path inductor and a transformer into a full magnetic coupling mode, adopting a parallel wire same-direction winding method when winding multi-path windings, and forcibly dividing abnormal current caused by inconsistent parameters such as switching devices, capacitors, loop parasitics and the like by utilizing the principle that equal coils of the windings are in phase and the windings are mutually embedded with the transformer.

Description

Circuit for solving primary multipath parallel current sharing by utilizing magnetic circuit full coupling

Technical Field

The utility model relates to an utilize the circuit that the primary multichannel was parallelly connected and is flow equalized in magnetic circuit total coupling solution.

Background

In the switching power supply, when a plurality of primary side branches are directly connected in parallel, static and dynamic non-uniform current can be caused by parameters such as internal threshold voltage and conduction internal resistance of the switching tube and external parameters such as loop stray inductance, parasitic capacitance and device dispersion.

With the improvement of the power grade and the density of the switching power supply, in order to solve the problem of insufficient capacity of the original device, a multi-path parallel connection mode is mostly adopted. And multiple branches are directly connected in parallel, and dynamic and static non-uniform currents are inevitably brought by self discrete parameters of a switch device, a capacitor and the like and loop parasitic parameters of layout wiring, a driving circuit and the like. The method of device screening, loop independence and the like is adopted, which brings a huge rise in cost.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems, when multiple paths are connected in parallel, a primary side inductor and a transformer are designed to be in a full magnetic coupling mode, and primary non-uniform current caused by the problem is solved by clamping the end voltage of the inductor and the end voltage of the transformer by using a principle similar to that of the transformer.

The technical scheme provided by the embodiment of the application is as follows:

when two parallel inductors are wound, two windings are wound on the same magnetic core in parallel and in the same direction, and the primary winding of the transformer is wound in the same way. Two paths of inductors and the primary of the transformer are highly coupled, two windings are induced in the same magnetic field, electromotive force is induced on one path of the other path when any path is excited, voltages at two ends of the inductors are clamped by a certain phase, the voltages of the certain phase are finally transformed, and the voltages are the same at each moment. In addition, the winding adopts double wires and is wound on the same magnetic core in a parallel winding way, so that the magnetic core is shown inThe sensitivity parameters from the sensors are highly consistent. According to the formula UL ═ Ldi (t)/dt, two paths i can be known_LThe same is true. The two half-bridge LLC topologies are directly connected in parallel, and a first parallel branch is connected with a resonant capacitor C1, a resonant inductor L1, a main transformer T1, a rectifier diode D1, a rectifier diode D2, a rectifier diode D3 and a rectifier diode D4 in series after being connected in parallel through a switching tube V1 and a switching tube V3, and then is connected with an output filter capacitor CD1 in parallel; after the second parallel branch is connected in parallel by the switching tubes V2 and V4, the second parallel branch is sequentially connected in series with a resonant capacitor C2, a resonant inductor L2, a main transformer T2, rectifier diodes D5, D6, D7 and D8, and connected in parallel with an output filter capacitor CD 3. The two half-bridges are driven identically, i.e. V1, V2 use the same DRIVE signal DRIVE1_ a and V3, V4 use the same DRIVE signal DRIVE1_ B. The branch 1 and the branch 2 work in the same state, primary current can simultaneously flow through L1 and L2, T1 and T2 in the same direction, parameters of L1 and L2, and parameters of T1 and T2 designed by the method are consistent and highly coupled, and induced electromotive force generated by the method is equivalent to the same direction. When the loop impedances of I1 and I2 are equal, the two branches I1 and I2 have the same size and direction, the inductance is the same as the induced voltage generated by the primary side of the transformer, and the two branches with the same terminal voltage do not block each other; when the impedances of loops where the I1 and the I2 are located are unequal, two paths of current tend to generate deviation, so that the induced voltage generated by an inductor wound in the same direction of an equal coil and a primary side of a transformer are different, the deviation of the generated induced voltage just resists to cause the current deviation external voltage, the voltage deviation of the inductor and the voltage of the transformer is finally compensated by a resonant capacitor, a switching device and the like, the same terminal voltage acts on the L1 and the L2 which have the same parameter height, and the T1 and the T2 to bring the same I1 and I2, so that the current equalization of the branch 1 and the branch 2 is realized.

The circuit can be further expanded to realize the parallel connection of more branches, and the method is characterized in that multiple paths of inductance windings are wound on the same magnetic core in parallel and in the same direction, and multiple paths of primary windings of the transformer are wound on the same magnetic core in parallel and in the same direction. The principle is that the two paths are connected in parallel.

By using the circuit, the independent current sharing of multiple paths of direct parallel connection can be realized, one set of driving circuit can be used for the multiple paths, the circuit topology is greatly simplified, the design method of the inductor and the transformer is optimized, and the cost of any other hardware is not increased. The method is realized by designing a direct parallel multi-path inductor and a transformer into a full magnetic coupling mode, adopting a parallel wire same-direction winding method when winding multi-path windings, and forcibly dividing abnormal current caused by inconsistent parameters such as switching devices, capacitors, loop parasitics and the like by utilizing the principle that equal coils of the windings are in phase and the windings are mutually embedded with the transformer.

Drawings

FIG. 1 shows a two-way LLC parallel embodiment of the present invention;

FIG. 2 is a circuit for performing simulation comparison of two parallel LLC topologies;

FIG. 3 is a 'independent inductor and transformer' simulation waveform;

FIG. 4 is a simulation waveform of a fully coupled inductor and transformer;

fig. 5 shows the circuit principle when three branches are connected in parallel.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the accompanying drawings and the detailed description.

Take two LLC in parallel as an example. When two parallel inductors are wound, two windings are wound on the same magnetic core in parallel and in the same direction, and the primary winding of the transformer is wound in the same way. Two paths of inductors and the primary of the transformer are highly coupled, two windings are induced in the same magnetic field, electromotive force is induced on one path of the other path when any path is excited, voltages at two ends of the inductors are clamped by a certain phase, the voltages of the certain phase are finally transformed, and the voltages are the same at each moment. In addition, because the winding adopts double wires and is wound on the same magnetic core in parallel, the inductance parameters expressed by the winding are highly consistent. From the formula UL ═ ldi (t)/dt, it can be seen that the two ils are identical. The circuit is shown in figure 1:

fig. 1 shows that two half-bridge LLC topologies are directly connected in parallel, the first parallel branch is composed of switching tubes V1, V3, a resonant capacitor C1, a resonant inductor L1, a main transformer T1, rectifier diodes D1, D2, D3, D4, and an output filter capacitor CD 1; the second parallel branch is composed of switching tubes V2 and V4, a resonant capacitor C2, a resonant inductor L2, a main transformer T2, rectifier diodes D5, D6, D7 and D8 and an output filter capacitor CD 3. The two half-bridges are driven identically, namely V1 and V2 use the same DRIVE signal DRIVE1_ A, V3 and V4 use the same DRIVE signal DRIVE1_ B, branch 1 and branch 2 work in the same state, primary current can flow through L1 and L2 and T1 and T2 simultaneously and in the same direction, L1 and L2 and T1 and T2 designed by the method are consistent in parameters and highly coupled, and induced electromotive force generated by the half-bridges is equivalent to the same direction. When the loop impedances of I1 and I2 are equal, the two branches I1 and I2 have the same size and direction, the inductance is the same as the induced voltage generated by the primary side of the transformer, and the two branches with the same terminal voltage do not block each other; when the impedances of loops where I1 and I2 are located are unequal, two paths of current tend to generate deviation, so that induced voltages generated at the primary side of an inductor and a transformer are different, the deviation of the generated induced voltages just resists to external voltages causing current deviation, the terminal voltages of the inductor and the transformer are the same finally, voltage deviation is compensated by a resonant capacitor, a switching device and the like, and the same terminal voltages act on L1 and L2, T1 and T2 with the same parameter height to bring the same I1 and I2, so that current equalization of a branch 1 and a branch 2 is realized. For two-way parallel LLC topology using the method and without the method, the simulation comparison circuit is as shown in fig. 2:

in fig. 2, the device discreteness can be reflected most directly by changing the resonant capacitance parameter, the parameter C2 parameter is changed to be positive deviation 20nF according to the deviation of changing the capacitance capacity of C1 and C2 by 10%, the C1 is set to be 200nF, the C2 is set to be 220nF, and other parameters are kept unchanged. Compared with simulation 'independent inductor and transformer' and 'full coupling inductor and transformer', the specific simulation waveforms are shown in fig. 3 and 4 in detail.

Fig. 3 is a simulation waveform of 'independent inductor and transformer', and fig. 4 is a simulation waveform of 'fully coupled inductor and transformer'. In the figure, IP1 and IP2 represent two primary currents, VL1 and VL2 represent two inductor terminal voltages, and VT1 and VT2 represent two transformer primary side end voltages. According to simulation results, after device deviation is introduced into the parallel circuit, a circuit with measures is not adopted, the voltage deviation between the two branch inductors and the terminal voltage of the transformer is large, and primary current poles are not uniform; the circuit using the method has the advantages that the two branch inductors are completely consistent with the terminal voltage of the transformer, and the primary current is relatively uniform and consistent.

The circuit can be further expanded to realize the parallel connection of more branches, and the method is characterized in that multiple paths of inductance windings are wound on the same magnetic core in parallel and in the same direction, and multiple paths of primary windings of the transformer are wound on the same magnetic core in parallel and in the same direction. The principle is that the two paths are connected in parallel. The specific circuit is shown in fig. 5 in detail, and fig. 5 shows a circuit principle when three branches are connected in parallel, so that parallel current sharing of more branches can be realized.

Claims

1. A circuit for solving the problem of primary multi-path parallel current sharing by utilizing magnetic circuit full coupling is characterized in that: the device comprises two half-bridge LLC topologies which are directly connected in parallel, wherein a first parallel branch is connected in parallel by switching tubes V1 and V3 and then sequentially connected in series with a resonant capacitor C1, a resonant inductor L1, a main transformer T1, rectifier diodes D1, D2, D3 and D4, and then connected in parallel with an output filter capacitor CD 1; after the second parallel branch is connected in parallel by the switching tubes V2 and V4, the second parallel branch is sequentially connected in series with a resonant capacitor C2, a resonant inductor L2, a main transformer T2, rectifier diodes D5, D6, D7 and D8 and a filter capacitor CD3 in parallel; the two half bridges are driven identically, a DRIVE signal DRIVE1_ A is connected with V1 and V2, and a DRIVE signal DRIVE1_ B is connected with V3 and V4; the two windings of L1 and L2 and T1 and T2 are respectively bifilarly wound and wound on the same magnetic core in the same direction.

2. The circuit of claim 1, wherein the circuit for solving the primary multi-path parallel current sharing by using the magnetic circuit full coupling comprises: the three-branch inductive windings are all wound on the same magnetic core in parallel and in the same direction, and the three-branch primary windings of the transformer are all wound on the same magnetic core in parallel and in the same direction.

3. A circuit for solving primary multi-path parallel current sharing by using magnetic circuit full coupling according to claim 1 or 2, wherein: the multiple paths of inductance windings are all wound on the same magnetic core in parallel and in the same direction, and the multiple paths of transformer primary windings are all wound on the same magnetic core in parallel and in the same direction.