Full-bridge converter module without blocking capacitor

Abstract

The utility model discloses a full-bridge converter module without a blocking capacitor. The full-bridge converter module comprises an input filtering unit, a first inversion bridge arm, a second inversion bridge arm, a planar transformer T, a first rectification bridge arm, a second rectification bridge arm, a planar inductor Lf, an output capacitor Co and a square wave detection unit M, the output capacitor Co is connected between the output positive end and the output negative end; a load Rload is connected between the output positive end and the output negative end; according to the full-bridge converter module, a planar magnetic technology is adopted, blocking capacitor configuration is avoided, positive and negative volt-second products are calculated through square wave voltage sampled by a resistance voltage division circuit and driving edge time captured by a comparator circuit, duty ratio control quantity is output, primary side full-bridge driving signal pulse width is dynamically adjusted, and magnetic flux balance control is achieved; the problem that the blocking capacitor occupies a large area is solved, and the high-power density design of the brick power supply module can be realized.

Description

Technical Field

[0001] This utility model relates to the field of power electronic power conversion technology, and in particular to a high-density full-bridge converter module based on planar magnetic technology that can achieve transformer flux balance without the need for DC blocking capacitors. Background Technology

[0002] Traditional full-bridge converters require a DC blocking capacitor connected in series with the primary winding of the transformer to achieve flux balance. However, this capacitor occupies a large area on the PCB, which is detrimental to improving power density in bulky power supplies. Furthermore, the charging and discharging process of the DC blocking capacitor introduces additional delay, limiting loop bandwidth. Existing technologies attempt to reduce magnetic bias through drive symmetry optimization, but magnetic saturation still occurs when the duty cycle deviation exceeds 0.5%.

[0003] Therefore, brick power supplies urgently need a solution that eliminates the need for DC blocking capacitors and allows for precise control of magnetic flux balance. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a full-bridge converter module that achieves magnetic flux balance without DC blocking capacitors.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a full-bridge converter module without DC blocking capacitor, including an input filtering unit, an inverter first bridge arm, an inverter second bridge arm, a planar transformer T, a rectifier first bridge arm, a rectifier second bridge arm, a planar inductor Lf, an output capacitor Co, and a square wave detection unit M; the output capacitor Co is connected between the output positive terminal and the output negative terminal; a load Rload is connected between the output positive terminal and the output negative terminal;

[0006] The input filtering unit includes an input filter inductor Lin and an input filter capacitor Cin. One end of the input filter inductor Lin is connected to the positive input terminal, and the other end of the input filter inductor Lin is connected to one end of the input filter capacitor Cin. The other end of the input filter capacitor Cin is connected to the negative input terminal. The first and second inverter bridge arms are connected in parallel across the two ends of the input filter capacitor Cin. The first and second rectifier bridge arms are connected in parallel across the two ends of the rectifier bridge arm. One end of the planar inductor Lf is electrically connected to one end of the second rectifier bridge arm. The other end of the planar inductor Lf is connected to the end of the output capacitor Co closest to the positive output terminal.

[0007] The first inverter bridge arm includes a first inverter power switch Q1 and a second inverter power switch Q2, which are connected in series and electrically connected between the two ends of the input filter capacitor Cin; the second inverter bridge arm includes a third inverter power switch Q3 and a fourth inverter power switch Q4, which are connected in series and electrically connected between the two ends of the input filter capacitor Cin.

[0008] The first rectifier bridge arm includes a first rectifier power switch S1 and a second rectifier power switch S2. The first rectifier power switch S1 and the second rectifier power switch S2 are connected in series and electrically connected between one end of the planar inductor Lf and one end of the output capacitor. The second rectifier bridge arm includes a third rectifier power switch S3 and a fourth rectifier power switch S4. The third rectifier power switch S3 and the fourth rectifier power switch S4 are connected in series and then connected in parallel with the first rectifier bridge arm.

[0009] The planar transformer T includes a primary winding and a secondary winding. The two ends of the primary winding are electrically connected to the midpoints of the first and second bridge arms of the inverter, respectively. The two ends of the secondary winding are electrically connected to the midpoints of the first and second bridge arms of the rectifier, respectively. A square wave detection unit is connected in parallel to the two ends of the second bridge arm of the rectifier to detect the rectified output square wave voltage.

[0010] The planar transformer T includes a first winding module and two first magnetic core modules respectively fastened to both sides of the winding module; the first winding module includes a first magnetic core central column through hole disposed on a circuit board, and the circuit board is symmetrically provided with a first side column through hole and a second side column through hole on both sides of the first magnetic core central column through hole, and the areas of the first magnetic core central column through hole, the first side column through hole and the second side column through hole are not equal.

[0011] The first magnetic core module of the planar transformer T is provided with a magnetic core center column that mates with the through hole of the first magnetic core center column, a first magnetic core side column that mates with the through hole of the first side column, and a second magnetic core side column that mates with the through hole of the second side column. The top surfaces of the first magnetic core center column, the top surfaces of the first magnetic core side column, and the top surfaces of the second magnetic core side column of the first magnetic core modules on both sides are in contact with each other.

[0012] The secondary winding of the planar transformer T is arranged on the inner layer of the circuit board around the through hole of the first magnetic core, and the primary winding is arranged on the inner layer of the circuit board around the through hole of the first magnetic core and is located on a different inner layer from the secondary winding. Both the secondary winding and the primary winding of the transformer T contain at least one turn of coil.

[0013] The planar inductor Lf includes a second winding module and two second magnetic core modules respectively fastened to both sides of the second winding module; the second winding module includes a through hole in the center of the second magnetic core disposed on the circuit board, and symmetrical through holes in the third and fourth side pillars on both sides of the through hole in the center of the second magnetic core, wherein the areas of the through hole in the center of the second magnetic core are not equal to those of the through holes in the third and fourth side pillars;

[0014] The second magnetic core module of the planar inductor Lf is provided with a second magnetic core central post that mates with the through hole of the second magnetic core central post, a third magnetic core side post that mates with the through hole of the third side post, and a fourth magnetic core side post that mates with the through hole of the fourth side post. The top surfaces of the second magnetic core central post, the top surfaces of the third magnetic core side post, and the top surfaces of the fourth magnetic core side post of the second magnetic core module on both sides are in contact with each other.

[0015] The planar inductor Lf winding is disposed on the inner layer of the circuit board around the through hole of the second magnetic core, and contains at least one turn of coil.

[0016] As a preferred embodiment, the square wave detection unit M includes a first resistor R1 and a second resistor R2 connected in series. The first resistor R1 and the second resistor R2 are connected in parallel across the two ends of the second bridge arm of the rectifier. The filter capacitor C1 is connected in parallel across the two ends of the second resistor R2. The sampling voltage point of the comparator U1 is set on the line connecting the first resistor R1 and the second resistor R2. The comparator U1 is electrically connected to the digital controller.

[0017] The beneficial effects of this utility model are as follows: The full-bridge converter module of this utility model adopts planar magnetic technology and has no DC blocking capacitor configuration. It calculates the positive and negative volt-second products and outputs the duty cycle control quantity by sampling the square wave voltage through the resistor voltage divider circuit and capturing the driving edge time through the comparator circuit. It dynamically adjusts the pulse width of the primary side full-bridge driving signal to achieve magnetic flux balance control, solves the problem of large board area occupied by DC blocking capacitors, and is conducive to realizing high power density design of brick power modules.

[0018] The square wave detection unit detects the rectified output square wave voltage, calculates the forward and reverse volt-second products for each switching cycle, and outputs a duty cycle compensation amount ΔD based on the difference between the positive and negative volt-second products. This dynamically adjusts the dead time of the primary-side full-bridge drive signal with an adjustment accuracy of ≤10ns. This eliminates the need for a DC blocking capacitor, thus improving power density. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the circuit topology of the full-bridge converter;

[0020] Figure 2 This is a 3D structural diagram of the full-bridge converter;

[0021] Figure 3 This is a three-dimensional structural diagram of the full-bridge converter from another angle;

[0022] Figure 4 This is a schematic diagram of the circuit board structure of this full-bridge converter;

[0023] Figure 5 This is a schematic diagram of the multi-layer structure of the circuit board of this full-bridge converter;

[0024] Figure 6This is a schematic diagram of the transformer core module of this full-bridge converter;

[0025] Figure 7 This is a schematic diagram of the inductor core module of this full-bridge converter;

[0026] Figure 8 This is a schematic diagram of the square wave detection unit M of the full-bridge converter;

[0027] Figure 9 This is the flowchart of the volt-second product control algorithm for this full-bridge converter;

[0028] Figure 10 This is a waveform diagram of the volt-second product control of this full-bridge converter;

[0029] In the diagram: 10. Second winding module; 11. Circuit board; 12. First side post through hole; 13. First core center post through hole; 14. Second side post through hole; 15. Third side post through hole; 16. Second core center post through hole; 17. Inductor second side post through hole; 18. First core module; 19. First core side post; 20. Core center post; 21. Second core side post; 22. Second core module; 23. Third core side post; 24. Second core center post; 25. Fourth core side post; 26. First winding module. Detailed Implementation

[0030] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. It should be understood that the embodiments in this application are merely illustrative of the principles and effects of this invention, as well as some examples of its application, and are not intended to limit this utility model. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this invention, and these modifications and improvements all fall within the protection scope of this utility model.

[0031] like Figure 1-7 As shown, a full-bridge converter module without DC blocking capacitor includes an input filter unit, an inverter first bridge arm, an inverter second bridge arm, a planar transformer T, a rectifier first bridge arm, a rectifier second bridge arm, a planar inductor Lf, an output capacitor Co, and a square wave detection unit M; the output capacitor Co is connected between the output positive terminal and the output negative terminal; a load Rload is connected between the output positive terminal and the output negative terminal.

[0032] The input filtering unit includes an input filter inductor Lin and an input filter capacitor Cin. One end of the input filter inductor Lin is connected to the positive input terminal, and the other end of the input filter inductor Lin is connected to one end of the input filter capacitor Cin. The other end of the input filter capacitor Cin is connected to the negative input terminal. The first and second inverter bridge arms are connected in parallel across the two ends of the input filter capacitor Cin. The first and second rectifier bridge arms are connected in parallel across the two ends of the rectifier bridge arm. One end of the planar inductor Lf is electrically connected to one end of the second rectifier bridge arm. The other end of the planar inductor Lf is connected to the end of the output capacitor Co closest to the positive output terminal.

[0033] The first inverter bridge arm includes a first inverter power switch Q1 and a second inverter power switch Q2, which are connected in series and electrically connected between the two ends of the input filter capacitor Cin; the second inverter bridge arm includes a third inverter power switch Q3 and a fourth inverter power switch Q4, which are connected in series and electrically connected between the two ends of the input filter capacitor Cin.

[0034] The first rectifier bridge arm includes a first rectifier power switch S1 and a second rectifier power switch S2. The first rectifier power switch S1 and the second rectifier power switch S2 are connected in series and electrically connected between one end of the planar inductor Lf and one end of the output capacitor. The second rectifier bridge arm includes a third rectifier power switch S3 and a fourth rectifier power switch S4. The third rectifier power switch S3 and the fourth rectifier power switch S4 are connected in series and then connected in parallel with the first rectifier bridge arm.

[0035] The planar transformer T includes a primary winding and a secondary winding. The two ends of the primary winding are electrically connected to the midpoints of the first and second bridge arms of the inverter, respectively. The two ends of the secondary winding are electrically connected to the midpoints of the first and second bridge arms of the rectifier, respectively. A square wave detection unit is connected in parallel to the two ends of the second bridge arm of the rectifier to detect the rectified output square wave voltage.

[0036] The planar transformer T includes a first winding module 26 and two first magnetic core modules 18 respectively fastened to both sides of the winding module; the first winding module 26 includes a first magnetic core central column through hole 13 that is disposed through the circuit board 11, and the circuit board 11 is symmetrically provided with a first side column through hole 12 and a second side column through hole 14 on both sides of the first magnetic core central column through hole, and the areas of the first magnetic core central column through hole 13, the first side column through hole 12 and the second side column through hole 14 are not equal;

[0037] The first magnetic core module 18 of the planar transformer T is provided with a magnetic core column 20 that mates with the first magnetic core column through hole 13, a first magnetic core side column 19 that mates with the first side column through hole 12, and a second magnetic core side column 21 that mates with the second side column through hole 14. The top surfaces of the first magnetic core column, the top surfaces of the first magnetic core side column, and the top surfaces of the second magnetic core side column of the first magnetic core module 18 on both sides are in contact with each other.

[0038] The secondary winding of the planar transformer T is arranged on the inner layer plate of the circuit board around the through hole 13 of the first magnetic core, and the primary winding is arranged on the inner layer plate of the circuit board 11 around the through hole 13 of the first magnetic core and is located on a different inner layer plate from the secondary winding. Both the secondary winding and the primary winding of the transformer T contain at least one turn of coil.

[0039] The planar inductor Lf includes a second winding module 10 and two second magnetic core modules 22 respectively fastened to both sides of the second winding module 10; the second winding module 10 includes a second magnetic core central column through hole 16 that is disposed through the circuit board 11, and a third side column through hole 15 and a fourth side column through hole 17 symmetrically disposed on both sides of the second magnetic core central column through hole 16, the areas of the second magnetic core central column through hole 16 and the third side column through hole 15 and the fourth side column through hole 17 are not equal;

[0040] The second magnetic core module 22 of the planar inductor Lf is provided with a second magnetic core post 24 that mates with the second magnetic core post through hole 16, a third magnetic core side post 23 that mates with the third side post through hole 15, and a fourth magnetic core side post 25 that mates with the fourth side post through hole 17. The top surfaces of the second magnetic core post, the top surfaces of the third magnetic core side post, and the top surfaces of the fourth magnetic core side post of the second magnetic core module 10 on both sides are in contact with each other.

[0041] The planar inductor Lf winding is disposed on the inner layer of the circuit board 11 around the through hole 16 in the center post of the second magnetic core, and contains at least one turn of coil.

[0042] The square wave detection unit M includes a first resistor R1 and a second resistor R2 connected in series. The first resistor R1 and the second resistor R2 are connected in parallel across the two ends of the second bridge arm of the rectifier. The filter capacitor C1 is connected in parallel across the two ends of the second resistor R2. The sampling voltage point of the comparator U1 is set on the line connecting the first resistor R1 and the second resistor R2. The comparator U1 is electrically connected to the digital controller.

[0043] The flux balance control method for a full-bridge converter module without DC blocking capacitor, as described above, is as follows:

[0044] Each control cycle t0-t4 is divided into 4 intervals. During time t0-t1, the first inverter power switch Q1 and the fourth inverter power switch Q4 are turned on, and the midpoint A of the first rectifier bridge arm and the midpoint B of the second rectifier bridge arm output a positive half-cycle square wave VAB. After passing through the power switch S1 of the first rectifier bridge arm and the power switch S4 of the second rectifier bridge arm, the output is V. RC The amplitude remains VAB; time t1-t2 is the dead time; time t2-t3, the second inverter power switch Q2 and the third inverter power switch Q3 are turned on, and the midpoint A of the first rectifier bridge arm and the midpoint B of the second rectifier bridge arm output a negative half-cycle square wave -VAB, which is then output as V by the power switch S2 of the first rectifier bridge arm and the power switch S3 of the second rectifier bridge arm. RC The amplitude is VAB; t3-t4 is the dead time;

[0045] V RC The voltage V is obtained by voltage division through series resistors R1 and R2 and filtering by capacitor C1. RC_sample Sampling voltage V RC_sample The voltage is passed to the digital controller as a rectified output square wave voltage; simultaneously, the sampled voltage V... RC_sample Compared with the voltage reference Vref, comparator U1 outputs a high level at time 0 and a low level at time t1. The digital controller takes t1-t0 as the positive half-cycle pulse width ton+. Comparator U1 outputs a high level at time t2 and a low level at time t3. The digital controller takes t3-t2 as the negative half-cycle pulse width ton-.

[0046] The digital controller calculates the volt-second product V during the positive half-cycle. RC_sample ·t on+ negative half-cycle V RC_sample ·t on- .

[0047] |V RC_sample ·t on+ -V RC_sample ·t on- When | > threshold, it indicates that the transformer flux is unbalanced and compensation adjustment is required; further judgment is needed when V RC_sample ·t on+ -V RC_sample ·t on- When the threshold is exceeded, the output duty cycle compensation is -ΔD, where ΔD = |t on+ -t on- | / T s T sDuring the switching cycle, the digital controller outputs a delay of Δt to the drive circuits of the second inverter power switch Q2 and the third inverter power switch Q3, increasing the drive pulse width of the second inverter power switch Q2 and the third inverter power switch Q3; otherwise, it outputs a duty cycle compensation amount +ΔD, where ΔD = |t| on+ -t on- | / T s T s The switching cycle is Δt, and after a delay of Δt, the output is given to the drive circuits of the first inverter power switch Q1 and the fourth inverter power switch Q4, increasing the drive pulse width of the first inverter power switch Q1 and the fourth inverter power switch Q4.

[0048] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some examples of its application, and are not intended to limit the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements are all within the protection scope of the present invention.

Claims

1. A full-bridge converter module without DC blocking capacitor, comprising an input filtering unit, an inverter first bridge arm, an inverter second bridge arm, a planar transformer T, a rectifier first bridge arm, a rectifier second bridge arm, a planar inductor Lf, an output capacitor Co, and a square wave detection unit M; the output capacitor Co is connected between the output positive terminal and the output negative terminal; a load Rload is connected between the output positive terminal and the output negative terminal; Its features are: The input filtering unit includes an input filtering inductor Lin and an input filtering capacitor Cin. One end of the input filtering inductor Lin is connected to the positive input terminal, and the other end of the input filtering inductor Lin is connected to one end of the input filtering capacitor Cin. The other end of the input filtering capacitor Cin is connected to the negative input terminal. The first inverter bridge arm and the second inverter bridge arm are connected in parallel across the two ends of the input filtering capacitor Cin. The first rectifier bridge arm and the second rectifier bridge arm are connected in parallel across their ends, and one end of the planar inductor Lf is electrically connected to one end of the second rectifier bridge arm. The other end of the planar inductor Lf is connected to the end of the output capacitor Co closest to the positive output terminal. The first inverter bridge arm includes a first inverter power switch Q1 and a second inverter power switch Q2, which are connected in series and electrically connected between the two ends of the input filter capacitor Cin; the second inverter bridge arm includes a third inverter power switch Q3 and a fourth inverter power switch Q4, which are connected in series and electrically connected between the two ends of the input filter capacitor Cin. The first rectifier bridge arm includes a first rectifier power switch S1 and a second rectifier power switch S2. The first rectifier power switch S1 and the second rectifier power switch S2 are connected in series and electrically connected between one end of the planar inductor Lf and one end of the output capacitor. The second rectifier bridge arm includes a third rectifier power switch S3 and a fourth rectifier power switch S4. The third rectifier power switch S3 and the fourth rectifier power switch S4 are connected in series and then connected in parallel with the first rectifier bridge arm. The planar transformer T includes a primary winding and a secondary winding. The two ends of the primary winding are electrically connected to the midpoints of the first and second bridge arms of the inverter, respectively. The two ends of the secondary winding are electrically connected to the midpoints of the first and second bridge arms of the rectifier, respectively. A square wave detection unit is connected in parallel to the two ends of the second bridge arm of the rectifier to detect the rectified output square wave voltage. The planar transformer T includes a first winding module (26) and two first magnetic core modules (18) respectively fastened to both sides of the winding module; the first winding module (26) includes a first magnetic core central column through hole (13) through the circuit board (11), and the circuit board (11) is symmetrically provided with a first side column through hole (12) and a second side column through hole (14) on both sides of the first magnetic core central column through hole, and the areas of the first magnetic core central column through hole (13) are not equal to those of the first side column through hole (12) and the second side column through hole (14); The first magnetic core module (18) of the planar transformer T is provided with a magnetic core column (20) that cooperates with the first magnetic core column through hole (13), a first magnetic core side column (19) that cooperates with the first side column through hole (12), and a second magnetic core side column (21) that cooperates with the second side column through hole (14). The top surfaces of the first magnetic core column, the top surfaces of the first magnetic core side column, and the top surfaces of the second magnetic core side column of the first magnetic core module (18) on both sides are in contact with each other. The secondary winding of the planar transformer T is arranged on the inner layer of the circuit board around the through hole (13) of the first magnetic core. The primary winding is arranged on the inner layer of the circuit board (11) around the through hole (13) of the first magnetic core and is located on a different inner layer from the secondary winding. Both the secondary winding and the primary winding of the transformer T contain at least one turn of coil. The planar inductor Lf includes a second winding module (10) and two second magnetic core modules (22) respectively fastened to both sides of the second winding module (10); the second winding module (10) includes a second magnetic core central column through hole (16) that is disposed through the circuit board (11), and a third side column through hole (15) and a fourth side column through hole (17) symmetrically disposed on both sides of the second magnetic core central column through hole (16), and the areas of the second magnetic core central column through hole (16) are not equal to those of the third side column through hole (15) and the fourth side column through hole (17); The second magnetic core module (22) of the planar inductor Lf is provided with a second magnetic core column (24) that cooperates with the second magnetic core column through hole (16), a third magnetic core side column (23) that cooperates with the third side column through hole (15), and a fourth magnetic core side column (25) that cooperates with the fourth side column through hole (17). The top surfaces of the second magnetic core column, the top surfaces of the third magnetic core side column, and the top surfaces of the fourth magnetic core side column of the second magnetic core module (22) on both sides are in contact with each other. The planar inductor Lf winding is disposed on the inner layer of the circuit board (11) around the through hole (16) of the second magnetic core, and contains at least one turn of coil.

2. The full-bridge converter module without DC blocking capacitor as described in claim 1, characterized in that: The square wave detection unit M includes a first resistor R1 and a second resistor R2 connected in series. The first resistor R1 and the second resistor R2 are connected in parallel across the two ends of the second bridge arm of the rectifier. The filter capacitor C1 is connected in parallel across the two ends of the second resistor R2. The sampling voltage point of the comparator U1 is set on the line connecting the first resistor R1 and the second resistor R2. The comparator U1 is electrically connected to the digital controller.

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