Power conversion device

Abstract

The invention provides further optimization for a six-switch flying capacitor step-down conversion circuit and a four-switch flying capacitor step-down conversion circuit applied to an intermediate bus converter. On one hand, the power conversion device is provided, the voltage spike of the switching tube is absorbed by optimizing the clamping circuit and the layout of the clamping circuit, the voltage stress of the switching tube is reduced, extra loss is not generated, and therefore the conversion efficiency of the power conversion device is improved. On the other hand, by optimizing the current sampling circuit, the monitoring and control performance related to the current is optimized, and the size of the power conversion device is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of high-frequency power supply, and in particular relates to a power conversion device. Background Art

[0002] With the development of artificial intelligence, the power requirements of intelligent data processing chips, such as GPU / CPU / NPU, etc. (collectively referred to as xPU) are getting higher and higher, which has greatly increased the power of servers, and the input voltage of servers has gradually changed from 12V to 48V. The operating voltage of xPU is getting lower and lower with the advancement of technology, gradually moving from 0.8V to 0.65V. Therefore, the gain ratio of output voltage to input voltage is getting lower and lower, making the two-stage buck circuit architecture gradually become the mainstream; and in order to obtain high 48V input to 0.65V output conversion efficiency, the intermediate bus voltage moves from 12V to 6.75V or even 3.3V.

[0003] The present invention provides a solution for a power conversion device with 48V input and 12V-3.3V regulated output, further improves the conversion efficiency of the power conversion device, and proposes a voltage spike clamping circuit for a switch tube during the operation of the power conversion device; and proposes a simple and easy-to-implement current sampling circuit and method for monitoring and controlling the working current of the power conversion device.

[0004] The present invention aims at the demand of power conversion devices with high power density and high conversion efficiency, further improves the conversion efficiency of the power conversion devices, and proposes a voltage spike clamping circuit of a switch tube during the operation of the power conversion device, which transmits the voltage spike energy absorbed by the clamping circuit to the output side or input side of the power conversion device to reduce the loss of the clamping circuit; and realizes current detection during the operation of the power conversion device through a simple and easy-to-implement current sampling circuit and method for monitoring and control. Summary of the invention

[0005] In view of this, one of the objects of the present invention is to provide a power conversion device, which reduces the voltage stress of the switch tube by optimizing the voltage spike clamping circuit and the layout of the switch tube and improves the conversion efficiency of the power conversion device.

[0006] Another object of the present invention is to provide a power conversion device, which optimizes the current-related monitoring and control performance and reduces the size of the power conversion device by optimizing the current sampling circuit.

[0007] In order to achieve the above object, the present invention provides a power conversion device on one hand, including an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal and three switch bridge arms, wherein the input negative terminal and the output negative terminal are short-circuited;

[0008] The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are electrically connected to a first lower node;

[0009] The power conversion device further includes a second lower switch, a magnetic component, a first flying capacitor, an input capacitor and an output capacitor, wherein the magnetic component includes a first end, a second end and a third end; the first end of the magnetic component is electrically connected to the first lower node, the second end of the magnetic component and the second lower switch are electrically connected to the second lower node, the second lower switch is connected between the second lower node and the input negative terminal, the third end of the magnetic component is electrically connected to the output positive terminal, and the first flying capacitor is connected between the first upper node and the second lower node;

[0010] The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal;

[0011] The power conversion device also includes a first clamping diode and a first absorption capacitor, wherein the positive electrode of the first clamping diode is electrically connected to the first lower node, the negative electrode of the first clamping diode is electrically connected to the first upper node, one end of the first absorption capacitor is electrically connected to the first upper node, and the other end of the first absorption capacitor is electrically connected to the second lower node.

[0012] Preferably, the first clamping diode and the first absorption capacitor are arranged adjacent to the first lower switch, and the second lower switch is arranged adjacent to the first lower switch.

[0013] Preferably, the power conversion device also includes a second upper switch, a second middle switch and a second flying capacitor; the second upper switch and the second middle switch are electrically connected to the second upper node, the second middle switch and the second lower switch are electrically connected to the second lower node, the second upper switch is electrically connected to the input positive terminal, and the second flying capacitor is connected between the second upper node and the first lower node.

[0014] Preferably, the power conversion device also includes a second clamping diode and a second absorption capacitor, the positive electrode of the second clamping diode is electrically connected to the second lower node, the negative electrode of the second clamping diode is electrically connected to the second upper node, one end of the second absorption capacitor is electrically connected to the second upper node, and the other end of the second absorption capacitor is electrically connected to the first lower node.

[0015] Preferably, it also includes a third clamping diode and a third absorption capacitor, the cathode of the third clamping diode is electrically connected to the second lower node, the anode of the third clamping diode is electrically connected to the input negative terminal, one end of the third absorption capacitor is electrically connected to the input positive terminal, and the other end of the third absorption capacitor is electrically connected to the input negative terminal.

[0016] Preferably, the power conversion device also includes a fourth clamping diode and a fourth absorption capacitor, the cathode of the fourth clamping diode is electrically connected to the first lower node, the anode of the fourth clamping diode is electrically connected to the input negative terminal, one end of the fourth absorption capacitor is electrically connected to the input positive terminal, and the other end of the fourth absorption capacitor is electrically connected to the input negative terminal.

[0017] Preferably, the power conversion device also includes a fifth clamping diode, a sixth clamping diode, a fifth absorption capacitor, a sixth absorption capacitor and a discharge resistor, the cathode of the fifth clamping diode is electrically connected to the first upper node, the anode of the fifth clamping diode is electrically connected to one end of the fifth absorption capacitor, and the other end of the fifth absorption capacitor is electrically connected to the input positive terminal; the anode of the sixth clamping diode is electrically connected to the second lower node, the cathode of the sixth clamping diode is electrically connected to one end of the sixth absorption capacitor, and the other end of the sixth absorption capacitor is electrically connected to the input negative terminal, and the discharge resistor is connected across the anode of the fifth clamping diode and the cathode of the sixth clamping diode.

[0018] Preferably, the power conversion device also includes a seventh clamping diode, a seventh absorption capacitor and a linear voltage stabilization circuit, the positive electrode of the seventh clamping diode is electrically connected to the second lower node, the negative electrode of the seventh clamping diode is electrically connected to one end of the seventh absorption capacitor, the other end of the seventh absorption capacitor is electrically connected to the input negative terminal, and the negative electrode of the seventh clamping diode is electrically connected to one end of the linear voltage stabilization circuit.

[0019] Preferably, the magnetic component includes a first low-voltage winding and a second low-voltage winding, and the first low-voltage winding and the second low-voltage winding are magnetically coupled; the non-same-name end of the first low-voltage winding and the same-name end of the second low-voltage winding are electrically connected to the output positive end, the same-name end of the first low-voltage winding is electrically connected to the first lower node, and the non-same-name end of the second low-voltage winding is electrically connected to the second lower node.

[0020] Preferably, the magnetic component includes an inductor winding, a first low-voltage winding and a second low-voltage winding, the first low-voltage winding and the second low-voltage winding are magnetically coupled; the same-name end of the first low-voltage winding is electrically connected to a first lower node, and the non-same-name end of the first low-voltage winding is electrically connected to a winding short-circuit point; the non-same-name end of the second low-voltage winding is electrically connected to a second lower node, and the same-name end of the second low-voltage winding is electrically connected to the winding short-circuit point; one end of the inductor winding is electrically connected to the winding short-circuit point, and the other end of the inductor winding is electrically connected to the output positive end.

[0021] Another aspect of the present invention provides a power conversion device, comprising an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal and three switch bridge arms, wherein the input negative terminal and the output negative terminal are short-circuited;

[0022] The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are electrically connected to a first lower node;

[0023] The power conversion device further includes a second lower switch, a winding combination, a first flying capacitor, an input capacitor and an output capacitor, wherein the winding combination includes a first end, a second end and a third end; the first end of the winding combination is electrically connected to the first lower node, the second end of the winding combination and the second lower switch are electrically connected to the second lower node, the second lower switch is connected between the second lower node and the input negative terminal, the third end of the winding combination is electrically connected to the output positive terminal, and the first flying capacitor is connected between the first upper node and the second lower node;

[0024] The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal;

[0025] The winding combination further includes a first low-voltage winding and a second low-voltage winding, wherein the first low-voltage winding and the second low-voltage winding are connected in series and bridged between the first end and the second end, and the number of turns of the first low-voltage winding is the same as the number of turns of the second low-voltage winding;

[0026] The power conversion device also includes a first clamping diode, a first absorption capacitor and a clamping bridge arm circuit; the positive electrode of the first clamping diode is electrically connected to the first lower node, and the negative electrode of the first clamping diode is electrically connected to the first clamping point; one end of the first absorption capacitor is electrically connected to the first clamping point, and the other end of the first absorption capacitor is electrically connected to the input negative end; one end of the clamping bridge arm circuit is electrically connected to the first clamping point, and the other end of the clamping bridge arm circuit is electrically connected to the input positive end; the clamping bridge arm circuit includes a clamping winding, and the clamping winding, the first low-voltage winding and the second low-voltage winding are magnetically coupled.

[0027] Preferably, the clamped bridge arm circuit is a clamped half-bridge circuit, and the clamped bridge arm circuit further comprises a third clamping diode, a fourth clamping diode, a third absorption capacitor, a fourth absorption capacitor, a second clamping point and a third clamping point;

[0028] The anode of the third clamping diode is electrically connected to the second clamping point, and the cathode of the third clamping diode is electrically connected to the input positive terminal; the anode of the fourth clamping diode is electrically connected to the first clamping point, and the cathode of the fourth clamping diode is electrically connected to the second clamping point; one end of the third absorption capacitor is electrically connected to the third clamping point, and the other end of the third absorption capacitor is electrically connected to the input positive terminal; one end of the fourth absorption capacitor is electrically connected to the first clamping point, and the other end of the fourth absorption capacitor is electrically connected to the third clamping point;

[0029] The clamping winding is connected between the second clamping point and the third clamping point; the number of turns of the clamping winding is the same as the number of turns of the first low-voltage winding.

[0030] Preferably, the clamped bridge arm circuit is a clamped full-bridge circuit, and the clamped bridge arm circuit further includes a third clamping diode, a fourth clamping diode, a fifth clamping diode, a sixth clamping diode, a second clamping point and a third clamping point;

[0031] The anode of the third clamping diode is electrically connected to the second clamping point, and the cathode of the third clamping diode is electrically connected to the input positive terminal; the anode of the fourth clamping diode is electrically connected to the first clamping point, and the cathode of the fourth clamping diode is electrically connected to the second clamping point; the anode of the fifth clamping diode is electrically connected to the third clamping point, and the cathode of the fifth clamping diode is electrically connected to the input positive terminal; the anode of the sixth clamping diode is electrically connected to the first clamping point, and the cathode of the sixth clamping diode is electrically connected to the third clamping point;

[0032] The clamping winding is connected between the second clamping point and the third clamping point; the number of turns of the clamping winding is twice the number of turns of the first low-voltage winding.

[0033] Preferably, the power conversion device also includes a second clamping diode and a second absorption capacitor; the positive electrode of the second clamping diode is electrically connected to the second lower node, and the negative electrode of the second clamping diode is electrically connected to the first clamping point; one end of the second absorption capacitor is electrically connected to the first clamping point, and the other end of the second absorption capacitor is electrically connected to the input negative terminal.

[0034] Preferably, the power conversion device also includes a second upper switch, a second middle switch and a second flying capacitor; the second upper switch and the second middle switch are electrically connected to the second upper node, the second middle switch and the second lower switch are electrically connected to the second lower node, the second upper switch is electrically connected to the input positive terminal, and the second flying capacitor is connected between the second upper node and the first lower node.

[0035] Preferably, the power conversion device also includes a third clamping diode and a third absorption capacitor; the cathode of the third clamping diode is electrically connected to the second lower node, and the anode of the third clamping diode is electrically connected to the input negative terminal; one end of the third absorption capacitor is electrically connected to the input positive terminal, and the other end of the third absorption capacitor is electrically connected to the input negative terminal.

[0036] Preferably, the power conversion device also includes a fourth clamping diode and a fourth absorption capacitor; the cathode of the fourth clamping diode is electrically connected to the first lower node, and the anode of the fourth clamping diode is electrically connected to the input negative terminal; one end of the fourth absorption capacitor is electrically connected to the input positive terminal, and the other end of the fourth absorption capacitor is electrically connected to the input negative terminal.

[0037] Another aspect of the present invention provides a power conversion device, comprising an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, three switch bridge arms, an upper node and a lower node, wherein the input negative terminal and the output negative terminal are short-circuited; the upper node comprises a first upper node and a second upper node, and the lower node comprises a first lower node and a second lower node;

[0038] The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are connected to a first lower node;

[0039] The power conversion device further includes a second lower switch, a winding combination, a first flying capacitor, an input capacitor and an output capacitor, wherein the winding combination includes a first end, a second end and a third end; the first end of the winding combination is electrically connected to the first lower node, the second end of the winding combination and the second lower switch are electrically connected to the second lower node, the second lower switch is connected between the second lower node and the input negative terminal, the third end of the winding combination is electrically connected to the output positive terminal, and the first flying capacitor is connected between the first upper node and the second lower node;

[0040] The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal;

[0041] The power conversion device also includes a first clamping diode, an absorption capacitor and a first linear voltage stabilization circuit, wherein the positive electrode of the first clamping diode is electrically connected to one of the lower nodes, the negative electrode of the first clamping diode is electrically connected to one end of the first absorption capacitor, the other end of the first absorption capacitor is electrically connected to the input negative terminal, and the negative electrode of the first clamping diode is electrically connected to one end of the linear voltage stabilization circuit.

[0042] Preferably, it also includes a third clamping diode and a third absorption capacitor, the cathode of the third clamping diode is electrically connected to the second lower node, the anode of the third clamping diode is electrically connected to the input negative terminal, one end of the absorption capacitor is electrically connected to the input positive terminal, and the other end of the absorption capacitor is electrically connected to the input negative terminal.

[0043] Preferably, it also includes a fifth clamping diode, a sixth clamping diode, a fifth absorption capacitor, a sixth absorption capacitor and a discharge resistor, the cathode of the fifth clamping diode is electrically connected to the first upper node, the anode of the fifth clamping diode is electrically connected to one end of the fifth absorption capacitor, and the other end of the fifth absorption capacitor is electrically connected to the input positive terminal; the anode of the sixth clamping diode is electrically connected to another of the lower nodes, the cathode of the sixth clamping diode is electrically connected to one end of the sixth absorption capacitor, and the other end of the sixth absorption capacitor is electrically connected to the input negative terminal, and the discharge resistor is connected across the anode of the fifth clamping diode and the cathode of the sixth clamping diode.

[0044] Preferably, it also includes a high-voltage winding, which is connected in series with the first flying capacitor between the first upper node and the second lower node; the high-voltage winding is coupled to the winding combination.

[0045] Another aspect of the present invention provides a power conversion device, comprising an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, three switch bridge arms, an upper node and a lower node, wherein the upper node comprises a first upper node and a second upper node, and the lower node comprises a first lower node and a second lower node; the input negative terminal and the output negative terminal are short-circuited;

[0046] The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and the three-switch bridge arm includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are connected to a first lower node;

[0047] The power conversion device further includes a second lower switch, a low-voltage winding, an inductor winding, a first flying capacitor, an input capacitor and an output capacitor; the low-voltage winding includes a first low-voltage winding and a second low-voltage winding, the first end of the first low-voltage winding is electrically connected to the first lower node, the first end of the second low-voltage winding is electrically connected to the second lower switch at the second lower node, the second end of the first low-voltage winding and the second end of the second low-voltage winding are electrically connected to one end of the inductor winding, and the other end of the inductor winding is electrically connected to the output positive end; the second lower switch is connected between the second lower node and the input negative end, and the first flying capacitor is connected between the first upper node and the second lower node;

[0048] The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal;

[0049] The power conversion device also includes an auxiliary winding, a first sampling resistor and a first sampling capacitor. The auxiliary winding, the first sampling resistor and the first sampling capacitor are electrically connected in series to form a first series sampling branch. The first series sampling branch is connected across one of the lower nodes and the output positive terminal. The auxiliary winding includes a first auxiliary winding and a second auxiliary winding. The first auxiliary winding is coupled to one of the low-voltage windings, and the second auxiliary winding is coupled to the inductor winding. The voltage across the first sampling capacitor is the first current sampling voltage.

[0050] Preferably, the first auxiliary winding and the second auxiliary winding are electrically connected in series, and the auxiliary winding is wound along a winding path of the low-voltage winding and the inductor winding.

[0051] Preferably, the first end of the second auxiliary winding and the first end of the inductor winding are the same end.

[0052] Preferably, it also includes a second upper switch, a second middle switch and a second flying capacitor; the second upper switch and the second middle switch are electrically connected to the second upper node, the second middle switch and the second lower switch are electrically connected to the second lower node, the second upper switch is electrically connected to the input positive terminal, and the second flying capacitor is connected between the second upper node and the first lower node.

[0053] Preferably, it also includes a transformer core and an inductor core; the transformer core includes two magnetic substrates, two transformer side columns and a transformer center column; the transformer side columns and the transformer center column are arranged between the two magnetic substrates, and are arranged in the order of side columns, center columns and side columns; the channels between the transformer center column and the transformer side columns are respectively the first transformer winding channel and the second transformer winding channel; the transformer core also includes two opposite sides, which are respectively the first transformer winding channel side and the second transformer winding channel side 1, and the first transformer winding channel and the second transformer winding channel both pass through the first transformer winding channel side and the second transformer winding channel side. Channel side; the inductor core includes two magnetic substrates, two inductor side columns and one inductor middle column; the inductor side columns and the inductor middle column are arranged between the two magnetic substrates, and are arranged in sequence according to the order of side columns, middle columns and side columns; the channels between the inductor middle column and the inductor side columns are respectively the first inductor winding channel and the second inductor winding channel; the inductor core also includes two opposite sides, namely the first inductor winding channel side and the second inductor winding channel side 1, and the first inductor winding channel and the second inductor winding channel both pass through the first inductor winding channel side and the second inductor winding channel side; the second transformer winding channel side is arranged adjacent to the first inductor winding channel side.

[0054] Preferably, the first auxiliary winding is wound around the transformer center column twice from the first end to the second end along the first direction, and then is wound around the transformer side column along the outer side of the transformer core from the first transformer winding channel side, and then passes through the second transformer winding channel side to be electrically connected to the second auxiliary winding; the second auxiliary winding is wound around the inductor center column twice from the first end to the second end along the second direction, passes through the first inductor winding channel side, and is electrically connected to the output positive pin of the power conversion circuit through the first sampling resistor and the first sampling capacitor connected in series.

[0055] Preferably, the auxiliary winding passes through the first transformer winding channel, the first inductor winding channel, the second inductor winding channel and the second transformer winding channel in sequence from the first end of the first auxiliary winding to the second end of the second auxiliary winding, and after being wound twice around the transformer center column and the inductor center column, it is electrically connected to the output positive pin of the power conversion circuit via the first sampling resistor and the first sampling capacitor connected in series.

[0056] The beneficial effects of the present invention are:

[0057] (1) By optimizing the voltage spike clamping circuit and layout of the switch tube, the voltage stress of the switch tube is reduced and the conversion efficiency of the power conversion device is improved.

[0058] (2) By optimizing the current sampling circuit, the current-related monitoring and control performance is optimized and the size of the power conversion device is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0060] Figures 1A to 1C is a schematic diagram of a six-switch power conversion circuit;

[0061] FIG. 2A to FIG. 2C is a schematic diagram of a four-switch power conversion circuit;

[0062] Figure 3A It is a schematic diagram of a clamping circuit of a power conversion circuit;

[0063] Figure 3B It is a schematic diagram of the clamping circuit and the lower switch layout;

[0064] Figure 3C and Figure 3D is another schematic diagram of a clamping circuit of a power conversion circuit;

[0065] Figure 4 is another schematic diagram of a clamping circuit of a power conversion circuit;

[0066] Figure 5A and Figure 5C It is a schematic diagram of a current sampling circuit of a power conversion circuit;

[0067] Figure 5B and Figure 5D The winding method of the auxiliary winding;

[0068] in:

[0069] 1a / 1b / 1c six-switch flying capacitor step-down power conversion circuit; 2a / 2b / 2c four-switch flying capacitor step-down power conversion circuit; 3a / 3b / 3c / 3d clamping circuit; 4 magnetic component; 5 transformer core; 6 inductor core; 11a / 11b transformer side column; 12 transformer center column; 13a / 13b transformer winding channel; 14a first transformer winding channel side;

[0070] 14b second transformer winding channel side; 21a / 21b inductor side column; 22 inductor middle column; 23a / 23b inductor winding channel;

[0071] 24a first inductor winding channel side; 24b second inductor winding channel side; A1 / A2 upper node; B1 / B2 lower node;

[0072] C1 / C2 flying capacitor; Ca filter capacitor; Cc1 / Cc2 sampling capacitor; Cin input capacitor; Co output capacitor;

[0073] CW21 / CW22 first auxiliary winding; CW1a / CW1b second auxiliary winding;

[0074] Dl1 / Dl2 / Dl3 / Dl4 / Dl5 / Dl6 / Dl7 clamping diodes; Cl1 / Cl2 / Cl3 / Cl4 / Cl5 / Cl6 / Cl7 absorption capacitors;

[0075] E1 / E2 / E3 clamping point; R1 discharge resistor; LW1 / LW1a / LW1b inductor winding; Q1 / Q3 upper switch; Q2 / Q4 middle switch; Rc1 / Rc2 sampling resistor; SR1 / SR2 lower switch; TL1 winding short-circuit point; TW12 / TW11 high voltage winding; TW21 / TW22 low voltage winding; TW31 clamping winding; Vc1 / Vc2 / Vc3 / Vc4 / Vc5 connection point; Vcs1 / Vcs2 sampling voltage; Vs voltage; Vin+ input positive terminal; Vin- input negative terminal; Vo+ output positive terminal; Vo- output negative terminal; DETAILED DESCRIPTION

[0076] One of the core aspects of the present invention is to provide a power conversion device, which reduces the voltage stress of the switch tube and improves the conversion efficiency of the power conversion device by optimizing the design of the clamping circuit and its layout; optimizes the current-related monitoring and control performance and reduces the size of the power conversion device by optimizing the current sampling circuit.

[0077] The present invention also provides a power conversion device, which optimizes the current-related monitoring and control performance and reduces the size of the power conversion device by optimizing the current sampling circuit.

[0078] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0079] Figures 1A to 1CThe six-switch flying capacitor step-down power conversion circuit shown in FIG. FIG. 2A to FIG. 2C The four-switch flying capacitor step-down power conversion circuit can be applied to an intermediate bus power conversion device with 48V input and 12V~3.3V regulated output.

[0080] Figures 1A to 1C The six-switch flying capacitor step-down power conversion circuit shown includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, two three-switch bridge arms, two flying capacitors, two low-voltage windings, and an input capacitor and an output capacitor. Figure 1A In the power conversion circuit 1a shown, the input negative terminal Vin- and the output negative terminal Vo- are short-circuited; the two three-switch bridge arms are respectively the first switch bridge arm 10a and the second switch bridge arm 10b, wherein the first switch bridge arm 10a includes an upper switch Q1, a middle switch Q2 and a lower switch SR1, the upper switch Q1 and the middle switch Q2 are electrically connected to the upper node A1, the middle switch Q2 and the lower switch SR1 are electrically connected to the lower node B1, the upper switch Q1 is electrically connected to the input positive terminal Vin+, and the lower switch SR1 is electrically connected to the input negative terminal Vin-; the second switch bridge arm 10b includes an upper switch Q3, a middle switch Q4 and a lower switch SR2, the upper switch Q3 and the middle switch Q4 are electrically connected to the upper node A2, the middle switch Q4 and the lower switch SR2 are electrically connected to the lower node B2, the upper switch Q3 is electrically connected Input positive terminal Vin+, lower switch SR2 is electrically connected to input negative terminal Vin-; input capacitor Cin is connected between input positive terminal Vin+ and input negative terminal Vin-, output capacitor Co is connected between output positive terminal Vo+ and output negative terminal Vo+; flying capacitor C1 is connected between upper node A1 of first switch bridge arm 10a and lower node B2 of second switch bridge arm 10b, flying capacitor C2 is connected between upper node A2 of second switch bridge arm 10b and lower node B1 of first switch bridge arm 10a; first end of low voltage winding TW21 is electrically connected to lower node B1, first end of low voltage winding TW22 is electrically connected to lower node B2, second end of low voltage winding TW21 and second end of low voltage winding TW22 are electrically connected to winding short-circuit point TL1, as shown in FIG. Figure 1A As shown, the winding short-circuit point TL1 is the output positive terminal Vo+; the low-voltage winding TW21 and the low-voltage winding TW22 are coupled on a magnetic core, and the first end of the low-voltage winding TW21 and the second end of the low-voltage winding TW22 are the same-named ends (ie, the same polarity), marked as point ends.

[0081] Figure 1B The power conversion circuit 1b shown in Figure 1A On the basis of the power conversion circuit 1a shown, the coupling coefficient between the low voltage winding TW21 and the low voltage winding TW22 is increased to be close to that of an ideal transformer, and an inductor LW1 is added and connected across the winding short-circuit point TL1 and the output positive terminal Vo+. Figure 1C The power conversion circuit 1c shown in FIG. Figure 1B On the basis of the power conversion circuit 1b shown, it also includes two high-voltage windings TW11 and TW12, the high-voltage windings TW11 and TW12 and the low-voltage windings TW21 and TW22 are wound on the same magnetic core, the high-voltage winding TW11 is electrically connected in series with the flying capacitor C1 and is connected across the upper node A1 and the lower node B2, the first end of the high-voltage winding TW11 is connected in series with the flying capacitor C1, and the second end of the high-voltage winding TW11 is short-circuited with the lower node B2; the high-voltage winding TW12 is electrically connected in series with the flying capacitor C2 and is connected across the upper node A2 and the lower node B1, the first end of the high-voltage winding TW12 is connected in series with the flying capacitor C2, and the second end of the high-voltage winding TW12 is short-circuited with the lower node B1; the second end of the high-voltage winding TW11, the first end of the high-voltage winding TW12, the first end of the low-voltage winding TW21 and the second end of the low-voltage winding TW22 are the same-named ends (that is, the same polarity) and are marked as point ends.

[0082] FIG. 2A to FIG. 2C The four-switch flying capacitor step-down power conversion circuit includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, a three-switch bridge arm, a lower switch SR2, a flying capacitor, two low-voltage windings, an input capacitor and an output capacitor. Figure 2A In the power conversion circuit 2a shown, the input negative terminal Vin- and the output negative terminal Vo- are short-circuited; the three-switch bridge arm includes an upper switch Q1, a middle switch Q2 and a lower switch SR1, the upper switch Q1 and the middle switch Q2 are electrically connected to an upper node A1, the middle switch Q2 and the lower switch SR1 are electrically connected to a lower node B1, the upper switch Q1 is electrically connected to the input positive terminal Vin+, and the lower switch SR1 is electrically connected to the input negative terminal Vin-; one end of the lower switch SR2 is electrically connected to the input negative terminal, and the other end is electrically connected to the lower node B2 ; The input capacitor Cin is connected between the input positive terminal Vin+ and the input negative terminal Vin-, and the output capacitor Co is connected between the output positive terminal Vo+ and the output negative terminal Vo-; the flying capacitor C1 is connected between the upper node A1 and the lower node B2; the first end of the low-voltage winding TW21 is electrically connected to the lower node B1, the first end of the low-voltage winding TW22 is electrically connected to the lower node B2, the second end of the low-voltage winding TW21 and the second end of the low-voltage winding TW22 are electrically connected to the winding short-circuit point TL1, as shown in Figure 2A As shown, the winding short-circuit point TL1 is the output positive terminal Vo+; the low-voltage winding TW21 and the low-voltage winding TW22 are coupled on a magnetic core, and the first end of the low-voltage winding TW21 and the second end of the low-voltage winding TW22 are the same-named ends (ie, the same polarity), marked as point ends.

[0083] Figure 2B The power conversion circuit 2b shown in FIG. Figure 2AOn the basis of the power conversion circuit 2a shown, the coupling coefficient between the low voltage winding TW21 and the low voltage winding TW22 is increased to be close to that of an ideal transformer, and an inductor LW1 is added and connected across the winding short-circuit point TL1 and the output positive terminal Vo+. Figure 2C The power conversion circuit 2c shown in FIG. Figure 2B On the basis of the power conversion circuit 2b shown, it also includes a high-voltage winding TW11, the high-voltage winding TW11 and the low-voltage windings TW21 and TW22 are wound on the same magnetic core, and the high-voltage winding TW11 is electrically connected in series with the flying capacitor C1 and bridged between the upper node A1 and the lower node B2, and the first end of the high-voltage winding TW11 is connected in series with the flying capacitor C1, and the second end of the high-voltage winding TW11 is short-circuited with the lower node B2; the second end of the high-voltage winding TW11, the first end of the low-voltage winding TW21 and the second end of the low-voltage winding TW22 are the same-named ends (that is, the same polarity) and are marked as point ends.

[0084] here, Figure 1A The low voltage windings TW21 and TW22 constitute a winding combination, the first end of the low voltage winding TW21 is the first end of the winding combination, the first end of the low voltage winding TW22 is the second end of the winding combination, and the second ends of the low voltage winding TW21 and the low voltage winding TW22 are the third end of the winding combination. Figure 1B and Figure 1C The low voltage windings TW21 and TW22 and the inductor winding LW1 in the winding combination constitute a winding combination, the first end of the low voltage winding TW21 is the first end of the winding combination, the first end of the low voltage winding TW22 is the second end of the winding combination, and the end of the inductor winding that is not electrically connected to the low voltage winding is the third end of the winding combination. Similarly, FIG. 2A to FIG. 2C The definition of winding combination can be found in Figures 1A to 1C The winding combination shown is defined and will not be repeated here.

[0085] Embodiment 1

[0086] In order to protect the switch tube in the power conversion circuit and to prevent the voltage spike at both ends of the switch tube from damaging the switch tube when the switch tube current is disconnected, the present invention provides an optimized switch tube voltage spike clamping circuit. Figure 1B The power conversion circuit 1b shown in FIG. 1 is used as an example. The power conversion device also includes clamping circuits 3a and 3b, such as Figure 3AAs shown, both clamping circuits 3a and 3b include clamping diodes and absorption capacitors, wherein clamping circuit 3a is used to protect the upper switch, and clamping circuit 3b is used to protect the lower switch. The clamping circuit 3b for protecting the lower switch SR1 includes a clamping diode Dl1 and an absorption capacitor Cl1, wherein the positive electrode of the clamping diode Dl1 is electrically connected to the lower node B1, the negative electrode of the clamping diode Dl1 is electrically connected to the upper node A1, and the absorption capacitor Cl1 is connected in parallel with the flying capacitor C1; similarly, the clamping circuit 3b for protecting the lower switch SR2 includes a clamping diode Dl2 and an absorption capacitor Cl2, wherein the positive electrode of the clamping diode Dl2 is electrically connected to the lower node B2, the negative electrode of the clamping diode Dl2 is electrically connected to the upper node A2, and the absorption capacitor Cl2 is connected in parallel with the flying capacitor C2. A clamping diode Dl1 and a flying capacitor Cl1 are added to the lower switch SR1, and as shown in FIG. Figure 3B The layout shown in the figure minimizes the area surrounded by the series branch formed by the clamping diode Dl1, the absorption capacitor Cl1 and the lower switch SR2 and the lower switch SR1; similarly, the clamping diode Dl2 and the flying capacitor Cl2 are added to the lower switch SR2, and Figure 3B The layout shown minimizes the area surrounded by the series branch formed by the clamping diode Dl2, the absorption capacitor Cl2 and the lower switch SR1 and the lower switch SR2. Take the switch SR1 as an example, when the lower switch SR1 is turned off, the lower switch SR2 is in the on state, and the voltage spike of the lower switch SR1 is stored in the absorption capacitor Cl1 through the clamping diode Dl1 and the lower switch SR2; and because the absorption capacitor Cl1 is connected in parallel with the flying capacitor C1, the excess energy of the absorption capacitor Cl1 can be transferred to the flying capacitor C1, so that the voltage across the absorption capacitor Cl1 and the flying capacitor C1 is the same, that is, equal to Vin / 2; this clamping circuit and layout method achieves the effect of effectively absorbing the voltage spike across the lower switch SR1 in each switching cycle, and feeding the voltage spike energy back to the flying capacitor in the power conversion circuit, thereby generating no additional loss. Similarly, the absorption capacitor Cl2, the clamping diode Dl2 and the lower switch SR1 have similar drain-source voltage clamping protection functions for the lower switch SR2, which will not be described here. Figure 3B The specific layout is that the lower switch SR1 and the absorption capacitor Cl1 and the absorption capacitor Cl2 and the lower switch SR2 are placed in sequence, and the absorption diodes Dl1 and Dl2 are placed on both sides of the absorption capacitors Cl1 and Cl2. The layout method is not limited to this. In short, the lower switches SR1 and SR2 are placed symmetrically, the absorption capacitors Cl1 and Cl2 are placed symmetrically, and the absorption diodes Dl1 and Dl2 are placed symmetrically, so that the loop formed by the lower switch SR1 and the absorption diode Dl1 and the absorption capacitor Cl1 and the lower switch SR2 is approximately equal to the loop formed by the lower switch SR2 and the absorption diode Dl2 and the absorption capacitor Cl2 and the lower switch SR1. The layout that achieves the minimum loop area at the same time meets the scope of the present invention.

[0087] The clamping circuit 3a for protecting the upper switch Q1 includes a clamping diode D13 and an absorption capacitor Cl3. The absorption capacitor Cl3 and the clamping diode D13 are arranged adjacent to the upper switch Q1, and the absorption capacitor Cl3 is connected across the input positive terminal Vin+ and the input negative terminal Vin-; the clamping diode D13 is electrically connected in series between the absorption capacitor Cl3 and the flying capacitor C1, with its positive electrode electrically connected to the input negative terminal Vin-, and its negative electrode electrically connected to the lower node B2; the series branch formed by the absorption capacitor Cl3, the clamping diode D13 and the flying capacitor C1 is connected in parallel to the drain-source terminals of the upper switch Q1 with the shortest distance, and forms a minimum loop; similarly The clamping circuit 3a for protecting the upper switch Q3 includes a clamping diode Dl4 and an absorption capacitor Cl4. The absorption capacitor Cl4 and the clamping diode Dl4 are arranged adjacent to the upper switch Q3, and the absorption capacitor Cl4 is connected across the input positive terminal Vin+ and the input negative terminal Vin-; the clamping diode Dl4 is electrically connected in series between the absorption capacitor Cl4 and the flying capacitor C2, with its positive electrode electrically connected to the input negative terminal Vin-, and its negative electrode electrically connected to the lower node B1; the series branch formed by the absorption capacitor Cl4, the clamping diode Dl4 and the flying capacitor C2 is connected in parallel at both ends of the drain and source of the upper switch Q3 with the shortest distance to form a minimum loop. When the upper switch Q1 is turned off, the absorption capacitor Cl3, the clamping diode D13 and the flying capacitor C1 absorb the voltage spike across the drain and source generated when the upper switch Q1 is turned off; and because the absorption capacitor Cl3 and the flying capacitor C1 can automatically balance their own charges through the power circuit, the absorption capacitor Cl3, the clamping diode D13 and the flying capacitor C1 can continuously absorb the voltage spike generated when the upper switch Q1 is turned off in each switching cycle without generating additional losses. Similarly, the absorption capacitor Cl4, the clamping diode D14 and the flying capacitor C2 have similar voltage clamping protection functions for the upper switch Q3, which will not be described in detail here.

[0088] Figure 3A The clamping circuits 3a and 3b shown are suitable for power conversion circuits 1b, such as Figures 1A to 1C as well as FIG. 2A to FIG. 2C In addition, in some application scenarios where the duty cycle of the upper switch is less than 0.5, the clamping circuits 3a and 3b can be used. When the duty cycle of the upper switch is greater than or equal to 0.5, this embodiment proposes another optimized voltage spike clamping circuit of the switch tube, such as Figure 3C and Figure 3D shown. Figure 3CThe clamping circuit 3c shown includes a clamping winding TW31, clamping diodes Dl1 / Dl2 / Dl3 / Dl4 and absorption capacitors Cl1 / Cl2 / Cl3 / Cl4. The positive electrode of the clamping diode Dl1 is electrically connected to the lower node B1, the negative electrode of the clamping diode Dl1 is electrically connected to one end of the absorption capacitor Cl1 at the clamping point E1, and the other end of the absorption capacitor Cl1 is electrically connected to the input negative terminal Vin-; that is, the series branch of the clamping diode Dl1 and the absorption capacitor Cl1 is connected in parallel at both ends of the lower switch SR1; the positive electrode of the clamping diode Dl2 is electrically connected to the lower node B2, the negative electrode of the clamping diode Dl2 is electrically connected to one end of the absorption capacitor Cl2 at the clamping point E1, and the other end of the absorption capacitor Cl2 is electrically connected to the input negative terminal Vin-; that is, the series branch of the clamping diode Dl2 and the absorption capacitor Cl2 is connected in parallel at both ends of the lower switch SR2; the negative electrode of the clamping diode Dl1 and the negative electrode of the clamping diode Dl2 are short-circuited at the clamping point E1. The negative electrode of the clamping diode D13 is electrically connected to the input positive terminal, the positive electrode of the clamping diode D13 is electrically connected to the negative electrode of the clamping diode D14 at the clamping point E2, and the positive electrode of the clamping diode D14 is electrically connected to the clamping point E1; one end of the absorption capacitor Cl3 is electrically connected to the input positive terminal, the other end of the absorption capacitor Cl3 is electrically connected to one end of the absorption capacitor Cl4 at the clamping point E3, and the other end of the absorption capacitor Cl4 is electrically connected to the clamping point E1; the clamping diodes D13 and D14, the absorption capacitors Cl3 and Cl4, and the clamping winding TW31 form a half-bridge circuit. The clamping winding TW31 is connected across the clamping points E2 and E3, and the clamping winding TW31 is coupled to the same magnetic core with the low-voltage windings TW21 and TW22, and the end electrically connected to the clamping point E2 is marked as a point end; here, the ratio of the number of turns of the two low-voltage windings and the clamping winding is 1:1:1. The peak energy of the lower switches SR1 and SR2 is stored in the absorption capacitors Cl1 and Cl2; the voltage across the low-voltage windings TW21 and TW22 is the alternating voltage Vin / 4, and the clamping winding TW31 couples the alternating voltage across the low-voltage windings TW21 and TW22, so that the voltage across the absorption capacitors Cl1 and Cl2 is clamped to Vin / 2, effectively clamping the voltage across the lower switches SR1 and SR2, and effectively absorbing excess peak energy, and feeding it back to the power conversion circuit 1b, reducing the energy loss of the power conversion circuit. Figure 3C The absorption capacitors Cl3 and Cl4 in can be replaced by clamping diodes Dl5 and Dl6, such as Figure 3D As shown, here, the clamping diodes D13 / D14 / D15 / D16 and the clamping winding TW31 form a full bridge circuit; the ratio of the number of turns of the two low-voltage windings and the clamping winding is 1:1:2. The cathode of the clamping diode D15 is electrically connected to the input positive terminal Vin+, the anode of the clamping diode D15 is electrically connected to the cathode of the clamping diode D16 at the clamping point E3, and the anode of the clamping diode D16 is electrically connected to the clamping point E1. Figure 3DThe clamping circuit 3d shown can also effectively clamp the voltage across the lower switches SR1 and SR2, and effectively absorb the excess peak energy and feed it back to the power conversion circuit 1b, thereby reducing the energy loss of the power conversion circuit. Figure 3A The clamp circuit 3a is shown, but is not limited to this. Figure 3C The clamp circuit 3c and Figure 3D The clamping circuit 3d shown is not limited to being applied to a power conversion circuit with a duty cycle greater than or equal to 0.5, but can also be applied to a power conversion circuit with a duty cycle less than 0.5.

[0089] Embodiment 2

[0090] The present invention also provides two switch tube voltage spike clamping circuits 3e and 3f. Figure 2C Taking the power conversion circuit 2c shown in FIG. 1 as an example, the power conversion device further includes clamping circuits 3e and 3f. Figure 4As shown. The clamping circuit 3e includes two clamping diodes D15 and D16, two absorption capacitors Cl5 and Cl6, and a discharge resistor R1. Among them, one end of the absorption capacitor Cl5 is electrically connected to the input positive terminal Vin+, the other end of Cl5 is electrically connected to the positive electrode of the clamping diode D15 at point Vc1, and the negative electrode of D15 is electrically connected to the upper node A1; one end of the absorption capacitor Cl6 is electrically connected to the input negative terminal Vin-, the other end of Cl6 is electrically connected to the negative electrode of the clamping diode D16 at point Vc2, and the positive electrode of D16 is electrically connected to the lower node B1; the discharge resistor R1 is connected across the points Vc1 and Vc2 (i.e., between the positive electrode of the clamping diode D15 and the negative electrode of the clamping diode D16). The clamping diode D15 and the absorption capacitor Cl5 are used to absorb the voltage spikes at both ends of the drain and source of the upper switch Q1, and the clamping diode D16 and the absorption capacitor Cl6 are used to absorb the voltage spikes at both ends of the drain and source of the lower switch SR1. The discharge resistor R1 provides an energy feedback path, so that the absorption capacitor C15 absorbs the energy after the capacitor C16 is connected in series, and can feed back the absorbed energy to the input capacitor Cin in a way with less loss; so that the absorption capacitor C15 or C16 can continuously absorb the voltage spikes at both ends of the drain and source of the corresponding switch in each switching cycle, and reduce the power loss of the power conversion device. In another embodiment, the positive electrode of the clamping diode D16 can also be electrically connected to the lower node B2, and used together with the absorption capacitor Cl6 to absorb the voltage spikes at both ends of the drain and source of the lower switch SR2. The clamping circuit 3f includes a clamping diode D17 and an absorption capacitor Cl7, one end of the absorption capacitor Cl7 is electrically connected to the input negative terminal Vin-, the other end of the absorption capacitor Cl7 and the negative electrode of the clamping diode D17 are electrically connected to the point Vc3, and the positive electrode of the clamping diode D17 is electrically connected to the lower node B2. The power conversion device also includes a linear voltage regulator circuit, and the input end of the linear voltage regulator circuit LDO is electrically connected to a point Vc3; the clamping circuit 3f is used to absorb the voltage spikes at both ends of the drain and source of the lower switch SR2, and the energy absorbed by the absorption capacitor C17 is provided to the linear voltage regulator circuit for powering the auxiliary circuit of the power conversion device, so that the absorption capacitor C17 can continuously absorb the voltage spikes at both ends of the drain and source of the lower switch SR2 in each switching cycle, and reduce the power loss of the power conversion device.

[0091] like Figure 3A The clamp circuits 3a and 3b shown, Figure 3C The clamp circuit 3c shown, Figure 3D The clamp circuit 3d shown and Figure 4 The clamping circuits 3e and 3f shown can be combined and applied to the power conversion devices 1a to 1c and 2a to 2c according to actual needs, and are not limited to Figure 3A The combination of the clamp circuits 3a and 3b shown, Figure 3C The clamp circuit 3c shown, Figure 3D The clamp circuit 3d shown and Figure 4The clamp circuits 3e and 3f are shown as a combination.

[0092] Embodiment 3

[0093] The present invention provides a current sampling circuit and method, which is suitable for Figure 1B and Figure 1C The power conversion circuits 1b and 1c shown in FIG. Figure 2B and Figure 2C The power conversion circuits 2b and 2c shown. Figure 1B The power conversion circuit 1b shown in FIG. Figure 5A As shown, the power conversion device also includes an auxiliary winding, a sampling resistor Rc1 and a sampling capacitor Cc1. The auxiliary winding, the sampling resistor Rc1 and the sampling capacitor Cc1 are electrically connected in series to form a sampling series branch of the output current, and the sampling series branch is connected between the lower node B1 and the output positive terminal Vo+. The auxiliary winding includes a first auxiliary winding CW21 and a second auxiliary winding CW1a. The first auxiliary winding CW21 is coupled with the low voltage winding TW21, and the second auxiliary winding CW1a is coupled with the inductor winding LW1; the first end of the first auxiliary winding CW21 is short-circuited with the lower node B1, the second end of the first auxiliary winding CW21 is short-circuited with the first end of the second auxiliary winding CW1a, and the second end of the second auxiliary winding CW1a is electrically connected to one end of the sampling resistor Rc1, the other end of the sampling resistor Rc1 is electrically connected to one end of the sampling capacitor Cc1, and the other end of the sampling capacitor Cc1 is electrically connected to the output positive terminal Vo+. The first end of the first auxiliary winding CW21 and the first end of the low voltage winding TW21 are the same end (i.e., the same polarity), marked as a point end; the first end of the second auxiliary winding CW1a and the winding short-circuit point TL1 of the inductor winding LW1 are the same end, marked as an * end; the voltage across the sampling capacitor Cc1 is the current sampling voltage Vcs1 of the power conversion circuit. The specific principle is that the voltage across the first auxiliary winding CW21 is used to offset the AC voltage across the low voltage winding TW21, and the voltage across the second auxiliary winding CW1a is used to offset the AC voltage across the inductor winding LW1. Because the sampling series branch is connected across the lower node B1 and the output positive terminal Vo+, the sampling voltage Vcs1 is equal to the DC component of the voltage between the lower node B1 and the output positive terminal Vo+, which reflects the magnitude of the output current of the power conversion circuit.

[0094] The winding method of the first auxiliary winding CW21 and the second auxiliary winding CW1a can refer to Figure 5B The power conversion device further comprises a transformer assembly and an inductor assembly, wherein the transformer assembly comprises a transformer core 5 and at least two low voltage windings TW21 and TW22, and the inductor assembly comprises an inductor core 6 and an inductor winding LW1.

[0095] The transformer core 5 includes two magnetic substrates (not shown), two transformer side columns 11a and 11b and a transformer center column 12, wherein the two transformer side columns 11a and 11b and the transformer center column 12 are arranged between the two magnetic substrates and are arranged in sequence in the order of side columns, center columns and side columns; the channel between the transformer center column 12 and the transformer side column 11a is the transformer winding channel 13a, and the channel between the transformer center column 12 and the transformer side column 11b is the transformer winding channel 13b; the magnetic core 10 also includes two opposite sides, namely the first transformer winding channel side 14a and the second transformer winding channel side 14b, and the transformer winding channel 13a and the transformer winding channel 13b both pass through the first transformer winding channel side 14a and the second transformer winding channel side 14b.

[0096] The inductor core 6 includes two magnetic substrates (not shown), two inductor side columns 21a and 21b and an inductor middle column 22, wherein the two inductor side columns 21a and 21b and the inductor middle column 22 are arranged between the two magnetic substrates and are arranged in sequence in the order of side columns, middle columns and side columns; the channel between the inductor middle column 22 and the inductor side column 21a is the inductor winding channel 23a, and the channel between the inductor middle column 22 and the inductor side column 21b is the inductor winding channel 23b; the inductor core 20 also includes two opposite sides, namely the first inductor winding channel side 24a and the second inductor winding channel side 24b.

[0097] The transformer core 5 and the inductor core 6 are placed side by side, so that the second transformer winding channel side 14b is adjacent to the first inductor winding channel side 24a, and the transformer winding channel 13a or the transformer winding channel 13b is approximately parallel to the inductor winding channel 23a or the inductor winding channel 23b; when the first transformer winding channel side 14a is defined as the left side of the magnetic component 4, the second inductor winding channel side 24b is the right side of the magnetic component 4; the upper side and the lower side of the magnetic core component 4 are located between the left side and the right side of the magnetic core component 4.

[0098] In this embodiment, the inductor winding LW1 is equivalently divided into two parts, LW1a and LW2a. The first winding includes a low-voltage winding TW21 and an inductor winding LW1a, and the second winding includes a low-voltage winding TW22 and an inductor winding LW1b. In this embodiment, the first end of the first winding (i.e., the first end of the low-voltage winding TW21) and the first end of the second winding (i.e., the first end of the low-voltage winding TW22) are both arranged on the first transformer winding channel side 14a, and the second end of the first winding (i.e., the output positive terminal Vo+ electrically connected to the inductor winding LW1a) and the second end of the second winding (i.e., the output positive terminal Vo+ electrically connected to the inductor winding LW1b) are both arranged on the lower side of the transformer assembly and the inductor assembly.

[0099] Detailed, such as Figure 5BAs shown, the low voltage winding TW21 is wound around the middle column 12 twice in the counterclockwise direction (defined as the first direction) from the first end to the second end; the second end of the low voltage winding TW21 is wound around the side column 11a along the outer side of the transformer magnetic core 10 from the first transformer winding channel side 14a, passes through the second transformer winding channel side 14b, and is electrically connected to the inductor winding LW1a. Then the inductor winding LW1a is wound around the inductor middle column 22 twice in the clockwise direction (defined as the second direction) from the first end to the second end, passes through the first inductor winding channel side 24a, and is electrically connected to the output positive terminal Vo+ (i.e., the output positive pin) of the power conversion circuit.

[0100] The first auxiliary winding CW21 is wound from the first end (i.e., the lower node B1) to the second end along the winding path of the low-voltage winding TW21, firstly wound around the middle column 12 in the counterclockwise direction for two turns, then wound around the side column 11a along the outer side of the transformer magnetic core 10 from the first transformer winding channel side 14a, and passes through the second transformer winding channel side 14b, and is electrically connected to the second auxiliary winding CW1a; then the second auxiliary winding CW1a is wound around the inductor middle column 22 in the clockwise direction from the first end to the second end, and after passing through the first inductor winding channel side 24a, is electrically connected to one end of the sampling resistor Rc1, the other end of the sampling resistor Rc1 is electrically connected to one end of the sampling capacitor Cc1, and the other end of the sampling capacitor Cc1 is electrically connected to the output positive terminal Vo+. By winding the first auxiliary winding CW21 and the second auxiliary winding CW1a along the winding paths of the low-voltage winding TW21 and the inductor winding LW1a respectively, the coupling of the first auxiliary winding CW21 and the low-voltage winding TW21 as well as the coupling of the second auxiliary winding CW2a and the inductor winding LW1a can be achieved, so that the voltage across the first auxiliary winding CW21 can offset the AC voltage across the low-voltage winding TW21, and the voltage across the second auxiliary winding CW1a can offset the AC voltage across the inductor winding L1a.

[0101] The auxiliary winding can also be Figure 5C As shown, the power conversion device also includes an auxiliary winding, a sampling resistor Rc2 and a sampling capacitor Cc2. The auxiliary winding, the sampling resistor Rc2 and the sampling capacitor Cc2 are electrically connected in series to form a sampling series branch of the output current. The sampling series branch is connected between the lower node B2 and the output positive terminal Vo+.

[0102] The auxiliary winding includes a first auxiliary winding CW22 and a second auxiliary winding CW1b, wherein the first auxiliary winding CW22 is coupled to the low voltage winding TW22, and the second auxiliary winding CW1b is coupled to the inductor winding LW1. The second end of the first auxiliary winding CW22 and the second end of the low voltage winding TW22 are the same end (i.e., the polarity is the same), and are marked as point ends; the first end of the second auxiliary winding CW1b and the winding short-circuit point TL1 end of the inductor winding LW1 are the same end, and are marked as * ends; and the first end of the first auxiliary winding CW22 is electrically connected to the lower node B2, the second end of the first auxiliary winding CW22 is electrically connected to the first end of the second auxiliary winding CW1b, the second end of CW1b is electrically connected to one end of the sampling resistor Rc2, the other end of the sampling resistor Rc2 is electrically connected to one end of the sampling capacitor Cc2, and the other end of the sampling capacitor Cc2 is electrically connected to the output positive terminal Vo+. The voltage across the sampling capacitor Cc2 is the current sampling voltage Vcs2 of the power conversion circuit. The specific principle is that the voltage across the first auxiliary winding CW22 is used to offset the AC voltage across the low-voltage winding TW22, and the voltage across the second auxiliary winding CW1b is used to offset the AC voltage across the inductor winding LW1. Because the sampling series branch is connected between the lower node B2 and the output positive terminal Vo+, the sampling voltage Vcs2 is equal to the DC component of the voltage between the lower node B2 and the output positive terminal Vo+, which reflects the output current of the power conversion circuit.

[0103] Detailed, such as Figure 5D As shown, the second winding (i.e., the low-voltage winding TW22 and the inductor winding LW1b) passes through the transformer winding channel 13a (this is a partial winding of the low-voltage winding TW22), the inductor winding channel 23a (this is a partial winding of the equivalent inductor winding LW1b), the inductor winding channel 23b (this is a partial winding of the equivalent inductor winding LW1b) and the transformer winding channel 13b (this is a partial winding of the low-voltage winding TW22) from the first end to the second end in sequence, that is, it completes one circle around the transformer center column 12 and the inductor center column 22 and reaches the midpoint X of the first winding; in this embodiment, after the second winding is wound around the transformer center column and the inductor center column twice, it is electrically connected to the output positive terminal Vo+ (i.e., the output positive pin) of the power conversion circuit.

[0104] Correspondingly, the auxiliary winding (i.e., the first auxiliary winding CW22 and the second auxiliary winding LW1b) passes through the transformer winding channel 13a (this is a partial winding of the first auxiliary winding CW22), the inductor winding channel 23a (this is a partial winding of the second auxiliary winding CW1b), the inductor winding channel 23b (this is a partial winding of the second auxiliary winding CW1b) and the transformer winding channel 13b (this is a partial winding of the first auxiliary winding CW22) from the first end of the first auxiliary winding CW22 to the second end of the second auxiliary winding LW1b along the winding path of the second winding, that is, it completes one circle around the transformer center column 12 and the inductor center column 22; in this embodiment, after the auxiliary winding is wound around the transformer center column and the inductor center column for two circles, it is electrically connected to one end of the sampling resistor Rc2, the other end of the sampling resistor Rc2 is electrically connected to one end of the sampling capacitor Cc2, and the other end of the sampling capacitor Cc2 is electrically connected to the output positive terminal Vo+. By winding the first auxiliary winding CW22 and the second auxiliary winding CW1b along the winding paths of the low-voltage winding TW22 and the inductor winding L1b respectively, the coupling of the first auxiliary winding CW22 and the low-voltage winding TW22, as well as the coupling of the second auxiliary winding CW1b and the inductor winding L1b can be achieved, so that the voltage across the first auxiliary winding CW21 can offset the AC voltage across the low-voltage winding TW21, and the voltage across the second auxiliary winding CW1a can offset the AC voltage across the low-voltage winding L1a.

[0105] In another embodiment, the first auxiliary winding CW22 and the second auxiliary winding CW1b are wound around the transformer middle column and the inductor middle column for one circle, and then electrically connected to one end of the sampling resistor Rc2, the other end of the sampling resistor Rc2 is electrically connected to one end of the sampling capacitor Cc2, and the other end of the sampling capacitor Cc2 is electrically connected to the output positive terminal Vo+; in this case, the first end of the first auxiliary winding CW22 is short-circuited with the midpoint X of the first winding. In this embodiment, the sampling voltage Vcs2 can also reflect the magnitude of the output current of the power conversion circuit.

[0106] In another embodiment, the power conversion device may also include two sampling series branches, respectively as follows: Figure 5A and Figure 5C As shown in the connection, two sampling voltages Vcs1 and Vcs2 are obtained at both ends of the two sampling capacitors Cc1 and Cc2 respectively; and further connecting the two sampling capacitors Cc1 and Cc2 in parallel can double the voltage amplitude of the sampling voltage Vcs1 or Vcs2, thereby improving the resolution of the current sampling circuit. The winding method can refer to Figure 5B and Figure 5D The winding method shown is not limited thereto, as long as the auxiliary winding is wound along the winding path of the low voltage winding and the inductor winding.

[0107] The current sampling circuit and method disclosed in the present invention obtain the current signal of the power conversion device through an auxiliary winding tightly coupled with the low-voltage winding and the inductor winding, and process it through a filtering and proportional unit. The method is simple and easy to implement, and can completely obtain the current signal of the power conversion device, so as to facilitate the controller to control or monitor the current of the power conversion device.

[0108] The magnetic columns (side columns and middle columns) in the transformer core or inductor core disclosed in the present invention can be independently formed with two magnetic substrates, or the magnetic columns can be integrally formed with one of the magnetic substrates, or each magnetic column can be divided into two parts, each part is integrally formed with one magnetic substrate; the transformer core material and the driving core material can both be ferrite. The cross section of the connection between the magnetic column of the transformer core or inductor core and the magnetic substrate and the cross section of the magnetic substrate can be rectangular, square, circular or elliptical, etc., but are not limited thereto.

[0109] The switch disclosed in the present invention can be SiMOSFET, SiCMOSFET, GaNMOSFET or IGBTMOSFET, etc., all of which can realize the function of the switch disclosed in the present invention.

[0110] The power conversion device described in the above embodiments may be a part of an electronic device or an independent power module, as long as it meets the technical features and benefits disclosed by the present invention.

[0111] The “equal”, “same” or “equal” disclosed in the present invention must take into account the parameter distribution of the project, and the error distribution is within ±30%; the definition of two line segments or two straight lines being “parallel” is that the angle between the two line segments or two straight lines is less than or equal to 45 degrees; the definition of two line segments or two straight lines being “perpendicular” is that the angle between the two line segments or two straight lines is within the range of [60, 120] degrees; the definition of phase “misalignment” also needs to take into account the parameter distribution of the project, and the error distribution of the misalignment degree is within ±30%.

[0112] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0113] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power conversion device, characterized in that: It includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal and three switch bridge arms, wherein the input negative terminal and the output negative terminal are short-circuited; The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are electrically connected to a first lower node; The power conversion device further includes a second lower switch, a magnetic component, a first flying capacitor, an input capacitor and an output capacitor, wherein the magnetic component includes a first end, a second end and a third end; the first end of the magnetic component is electrically connected to the first lower node, the second end of the magnetic component and the second lower switch are electrically connected to the second lower node, the second lower switch is connected between the second lower node and the input negative terminal, the third end of the magnetic component is electrically connected to the output positive terminal, and the first flying capacitor is connected between the first upper node and the second lower node; The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal; The power conversion device also includes a first clamping diode and a first absorption capacitor, wherein the positive electrode of the first clamping diode is electrically connected to the first lower node, the negative electrode of the first clamping diode is electrically connected to the first upper node, one end of the first absorption capacitor is electrically connected to the first upper node, and the other end of the first absorption capacitor is electrically connected to the second lower node.

2. The power conversion device according to claim 1, characterized in that: The first clamping diode and the first absorption capacitor are disposed adjacent to the first lower switch, and the second lower switch is disposed adjacent to the first lower switch.

3. The power conversion device according to claim 1, characterized in that: The power conversion device also includes a second upper switch, a second middle switch and a second flying capacitor; the second upper switch and the second middle switch are electrically connected to the second upper node, the second middle switch and the second lower switch are electrically connected to the second lower node, the second upper switch is electrically connected to the input positive terminal, and the second flying capacitor is connected between the second upper node and the first lower node.

4. The power conversion device according to claim 3, characterized in that: The power conversion device also includes a second clamping diode and a second absorption capacitor, the positive electrode of the second clamping diode is electrically connected to the second lower node, the negative electrode of the second clamping diode is electrically connected to the second upper node, one end of the second absorption capacitor is electrically connected to the second upper node, and the other end of the second absorption capacitor is electrically connected to the first lower node.

5. The power conversion device according to claim 1, characterized in that: It also includes a third clamping diode and a third absorption capacitor; the cathode of the third clamping diode is electrically connected to the second lower node, and the anode of the third clamping diode is electrically connected to the input negative terminal; one end of the third absorption capacitor is electrically connected to the input positive terminal, and the other end of the third absorption capacitor is electrically connected to the input negative terminal.

6. The power conversion device according to claim 3, characterized in that: It also includes a fourth clamping diode and a fourth absorption capacitor; the cathode of the fourth clamping diode is electrically connected to the first lower node, and the anode of the fourth clamping diode is electrically connected to the input negative terminal; one end of the fourth absorption capacitor is electrically connected to the input positive terminal, and the other end of the fourth absorption capacitor is electrically connected to the input negative terminal.

7. The power conversion device according to claim 1, characterized in that: It also includes a fifth clamping diode, a sixth clamping diode, a fifth absorption capacitor, a sixth absorption capacitor and a discharge resistor, wherein the cathode of the fifth clamping diode is electrically connected to the first upper node, the anode of the fifth clamping diode is electrically connected to one end of the fifth absorption capacitor, and the other end of the fifth absorption capacitor is electrically connected to the input positive terminal; the anode of the sixth clamping diode is electrically connected to the second lower node, the cathode of the sixth clamping diode is electrically connected to one end of the sixth absorption capacitor, and the other end of the sixth absorption capacitor is electrically connected to the input negative terminal, and the discharge resistor is connected across the anode of the fifth clamping diode and the cathode of the sixth clamping diode.

8. The power conversion device according to claim 1, characterized in that: It also includes a seventh clamping diode, a seventh absorption capacitor and a linear voltage stabilization circuit, wherein the anode of the seventh clamping diode is electrically connected to the second lower node, the cathode of the seventh clamping diode is electrically connected to one end of the seventh absorption capacitor, the other end of the seventh absorption capacitor is electrically connected to the input negative terminal, and the cathode of the seventh clamping diode is electrically connected to one end of the linear voltage stabilization circuit.

9. The power conversion device according to claim 1, characterized in that: The magnetic component includes a first low-voltage winding and a second low-voltage winding, and the first low-voltage winding and the second low-voltage winding are magnetically coupled; the non-same-name end of the first low-voltage winding and the same-name end of the second low-voltage winding are electrically connected to the output positive end, the same-name end of the first low-voltage winding is electrically connected to the first lower node, and the non-same-name end of the second low-voltage winding is electrically connected to the second lower node.

10. The power conversion device according to claim 1, characterized in that: The magnetic component includes an inductor winding, a first low-voltage winding and a second low-voltage winding, the first low-voltage winding and the second low-voltage winding are magnetically coupled; the same-name end of the first low-voltage winding is electrically connected to a first lower node, and the non-same-name end of the first low-voltage winding is electrically connected to a winding short-circuit point; the non-same-name end of the second low-voltage winding is electrically connected to a second lower node, and the same-name end of the second low-voltage winding is electrically connected to the winding short-circuit point; one end of the inductor winding is electrically connected to the winding short-circuit point, and the other end of the inductor winding is electrically connected to the output positive end.

11. A power conversion device, characterized in that: It includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal and three switch bridge arms, wherein the input negative terminal and the output negative terminal are short-circuited; The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are electrically connected to a first lower node; The power conversion device further includes a second lower switch, a winding combination, a first flying capacitor, an input capacitor and an output capacitor, wherein the winding combination includes a first end, a second end and a third end; the first end of the winding combination is electrically connected to the first lower node, the second end of the winding combination and the second lower switch are electrically connected to the second lower node, the second lower switch is connected between the second lower node and the input negative terminal, the third end of the winding combination is electrically connected to the output positive terminal, and the first flying capacitor is connected between the first upper node and the second lower node; The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal; The winding combination further includes a first low-voltage winding and a second low-voltage winding, wherein the first low-voltage winding and the second low-voltage winding are connected in series and bridged between the first end and the second end, and the number of turns of the first low-voltage winding is the same as the number of turns of the second low-voltage winding; The power conversion device also includes a first clamping diode, a first absorption capacitor and a clamping bridge arm circuit; the positive electrode of the first clamping diode is electrically connected to the first lower node, and the negative electrode of the first clamping diode is electrically connected to the first clamping point; one end of the first absorption capacitor is electrically connected to the first clamping point, and the other end of the first absorption capacitor is electrically connected to the input negative end; one end of the clamping bridge arm circuit is electrically connected to the first clamping point, and the other end of the clamping bridge arm circuit is electrically connected to the input positive end; the clamping bridge arm circuit includes a clamping winding, and the clamping winding, the first low-voltage winding and the second low-voltage winding are magnetically coupled.

12. The power conversion device according to claim 11, characterized in that: The clamped bridge arm circuit is a clamped half-bridge circuit, and the clamped bridge arm circuit further includes a third clamping diode, a fourth clamping diode, a third absorption capacitor, a fourth absorption capacitor, a second clamping point and a third clamping point; The anode of the third clamping diode is electrically connected to the second clamping point, and the cathode of the third clamping diode is electrically connected to the input positive terminal; the anode of the fourth clamping diode is electrically connected to the first clamping point, and the cathode of the fourth clamping diode is electrically connected to the second clamping point; one end of the third absorption capacitor is electrically connected to the third clamping point, and the other end of the fourth absorption capacitor is electrically connected to the input positive terminal; one end of the fourth absorption capacitor is electrically connected to the first clamping point, and the other end of the fourth absorption capacitor is electrically connected to the third clamping point; The clamping winding is connected between the second clamping point and the third clamping point; the number of turns of the clamping winding is the same as the number of turns of the first low-voltage winding.

13. The power conversion device according to claim 11, characterized in that: The clamping bridge arm circuit is a clamping full-bridge circuit, and the clamping bridge arm circuit further includes a third clamping diode, a fourth clamping diode, a fifth clamping diode, a sixth clamping diode, a second clamping point and a third clamping point; The anode of the third clamping diode is electrically connected to the second clamping point, and the cathode of the third clamping diode is electrically connected to the input positive terminal; the anode of the fourth clamping diode is electrically connected to the first clamping point, and the cathode of the fourth clamping diode is electrically connected to the second clamping point; the anode of the fifth clamping diode is electrically connected to the third clamping point, and the cathode of the fifth clamping diode is electrically connected to the input positive terminal; the anode of the sixth clamping diode is electrically connected to the first clamping point, and the cathode of the sixth clamping diode is electrically connected to the third clamping point; The clamping winding is connected between the second clamping point and the third clamping point; the number of turns of the clamping winding is twice the number of turns of the first low-voltage winding.

14. The power conversion device according to claim 11, characterized in that: It also includes a second clamping diode and a second absorption capacitor; the anode of the second clamping diode is electrically connected to the second lower node, and the cathode of the second clamping diode is electrically connected to the first clamping point; one end of the second absorption capacitor is electrically connected to the first clamping point, and the other end of the second absorption capacitor is electrically connected to the input negative terminal.

15. The power conversion device according to claim 11, characterized in that: It also includes a second upper switch, a second middle switch and a second flying capacitor; the second upper switch and the second middle switch are electrically connected to the second upper node, the second middle switch and the second lower switch are electrically connected to the second lower node, the second upper switch is electrically connected to the input positive terminal, and the second flying capacitor is connected between the second upper node and the first lower node.

16. The power conversion device according to claim 11, characterized in that: It also includes a third clamping diode and a third absorption capacitor; the cathode of the third clamping diode is electrically connected to the second lower node, and the anode of the third clamping diode is electrically connected to the input negative terminal; one end of the third absorption capacitor is electrically connected to the input positive terminal, and the other end of the third absorption capacitor is electrically connected to the input negative terminal.

17. The power conversion device according to claim 15, characterized in that: It also includes a fourth clamping diode and a fourth absorption capacitor; the cathode of the fourth clamping diode is electrically connected to the first lower node, and the anode of the fourth clamping diode is electrically connected to the input negative terminal; one end of the fourth absorption capacitor is electrically connected to the input positive terminal, and the other end of the fourth absorption capacitor is electrically connected to the input negative terminal.

18. A power conversion device, characterized in that: It includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, a three-switch bridge arm, an upper node and a lower node, wherein the input negative terminal and the output negative terminal are short-circuited; the upper node includes a first upper node and a second upper node, and the lower node includes a first lower node and a second lower node; The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are connected to a first lower node; The power conversion device further includes a second lower switch, a winding combination, a first flying capacitor, an input capacitor and an output capacitor, wherein the winding combination includes a first end, a second end and a third end; the first end of the winding combination is electrically connected to the first lower node, the second end of the winding combination and the second lower switch are electrically connected to the second lower node, the second lower switch is connected between the second lower node and the input negative terminal, the third end of the winding combination is electrically connected to the output positive terminal, and the first flying capacitor is connected between the first upper node and the second lower node; The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal; The power conversion device also includes a first clamping diode, an absorption capacitor and a first linear voltage stabilization circuit, wherein the positive electrode of the first clamping diode is electrically connected to one of the lower nodes, the negative electrode of the first clamping diode is electrically connected to one end of the first absorption capacitor, the other end of the first absorption capacitor is electrically connected to the input negative terminal, and the negative electrode of the first clamping diode is electrically connected to one end of the linear voltage stabilization circuit.

19. The power conversion device according to claim 18, characterized in that: It also includes a third clamping diode and a third absorption capacitor, wherein the cathode of the third clamping diode is electrically connected to the second lower node, the anode of the third clamping diode is electrically connected to the input negative terminal, one end of the absorption capacitor is electrically connected to the input positive terminal, and the other end of the absorption capacitor is electrically connected to the input negative terminal.

20. The power conversion device according to claim 18, characterized in that: It also includes a fifth clamping diode, a sixth clamping diode, a fifth absorption capacitor, a sixth absorption capacitor and a discharge resistor, wherein the cathode of the fifth clamping diode is electrically connected to the first upper node, the anode of the fifth clamping diode is electrically connected to one end of the fifth absorption capacitor, and the other end of the fifth absorption capacitor is electrically connected to the input positive terminal; the anode of the sixth clamping diode is electrically connected to another of the lower nodes, the cathode of the sixth clamping diode is electrically connected to one end of the sixth absorption capacitor, and the other end of the sixth absorption capacitor is electrically connected to the input negative terminal, and the discharge resistor is connected across the anode of the fifth clamping diode and the cathode of the sixth clamping diode.

21. The power conversion device according to claim 18, characterized in that: It also includes a high-voltage winding, which is connected in series with the first flying capacitor and spans between the first upper node and the second lower node; the high-voltage winding is coupled to the winding combination.

22. A power conversion device, characterized in that: It includes an input positive terminal, an input negative terminal, an output positive terminal, an output negative terminal, a three-switch bridge arm, an upper node and a lower node, wherein the upper node includes a first upper node and a second upper node, and the lower node includes a first lower node and a second lower node; the input negative terminal and the output negative terminal are short-circuited; The three-switch bridge arm is connected between the input positive terminal and the input negative terminal, and the three-switch bridge arm includes a first upper switch, a first middle switch and a first lower switch, wherein the first upper switch and the first middle switch are electrically connected to a first upper node, and the first middle switch and the first lower switch are connected to a first lower node; The power conversion device further includes a second lower switch, a low-voltage winding, an inductor winding, a first flying capacitor, an input capacitor and an output capacitor; the low-voltage winding includes a first low-voltage winding and a second low-voltage winding, the first end of the first low-voltage winding is electrically connected to the first lower node, the first end of the second low-voltage winding is electrically connected to the second lower switch at the second lower node, the second end of the first low-voltage winding and the second end of the second low-voltage winding are electrically connected to one end of the inductor winding, and the other end of the inductor winding is electrically connected to the output positive end; the second lower switch is connected between the second lower node and the input negative end, and the first flying capacitor is connected between the first upper node and the second lower node; The input capacitor is connected between the input positive terminal and the input negative terminal, and the output capacitor is connected between the output positive terminal and the output negative terminal; The power conversion device further includes an auxiliary winding, a first sampling resistor and a first sampling capacitor. The auxiliary winding, the first sampling resistor and the first sampling capacitor are electrically connected in series to form a first series sampling branch. The first series sampling branch is connected across one of the lower nodes and the output positive terminal. The auxiliary winding includes a first auxiliary winding and a second auxiliary winding. The first auxiliary winding is coupled to one of the low-voltage windings, and the second auxiliary winding is coupled to the inductor winding. The voltage across the first sampling capacitor is a first current sampling voltage. The first auxiliary winding and the second auxiliary winding are electrically connected in series, and the auxiliary winding is wound along the winding path of the low-voltage winding and the inductor winding.

23. The power conversion device according to claim 22, characterized in that: The first end of the second auxiliary winding and the first end of the inductor winding are the same end.

24. The power conversion device according to claim 22, characterized in that: It also includes a second upper switch, a second middle switch and a second flying capacitor; the second upper switch and the second middle switch are electrically connected to the second upper node, the second middle switch and the second lower switch are electrically connected to the second lower node, the second upper switch is electrically connected to the input positive terminal, and the second flying capacitor is connected between the second upper node and the first lower node.

25. The power conversion device according to claim 22, characterized in that: It also includes a transformer core and an inductor core; the transformer core includes two magnetic substrates, two transformer side columns and a transformer center column; the transformer side columns and the transformer center column are arranged between the two magnetic substrates, and are arranged in the order of the side columns, the center column and the side columns; the channels between the transformer center column and the transformer side columns are respectively the first transformer winding channel and the second transformer winding channel; the transformer core also includes two opposite sides, which are respectively the first transformer winding channel side and the second transformer winding channel side 1, and the first transformer winding channel and the second transformer winding channel both pass through the first transformer winding channel side and the second transformer winding channel side; the inductor core includes two magnetic substrates, two inductor side columns and one inductor middle column; the inductor side columns and the inductor middle column are arranged between the two magnetic substrates, and are arranged in sequence according to the order of side columns, middle columns and side columns; the channels between the inductor middle column and the inductor side columns are respectively the first inductor winding channel and the second inductor winding channel; the inductor core also includes two opposite sides, namely the first inductor winding channel side and the second inductor winding channel side 1, and the first inductor winding channel and the second inductor winding channel both pass through the first inductor winding channel side and the second inductor winding channel side; the second transformer winding channel side is arranged adjacent to the first inductor winding channel side.

26. The power conversion device according to claim 25, characterized in that: The first auxiliary winding is wound around the transformer center column twice along the first direction from the first end to the second end, and then is wound around the transformer side column along the outer side of the transformer core from the first transformer winding channel side, and then passes through the second transformer winding channel side to be electrically connected to the second auxiliary winding; the second auxiliary winding is wound around the inductor center column twice along the second direction from the first end to the second end, passes through the first inductor winding channel side, and is electrically connected to the output positive pin of the power conversion circuit through the first sampling resistor and the first sampling capacitor connected in series.

27. The power conversion device according to claim 25, characterized in that: The auxiliary winding passes through the first transformer winding channel, the first inductor winding channel, the second inductor winding channel and the second transformer winding channel in sequence from the first end of the first auxiliary winding to the second end of the second auxiliary winding, and is wound around the transformer center column and the inductor center column twice, and is electrically connected to the output positive pin of the power conversion circuit via the first sampling resistor and the first sampling capacitor connected in series.

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