Magnetic bias suppression transformer

Abstract

The invention discloses a magnetic bias suppression transformer which comprises a heat conduction plate, a first O-shaped magnetic core, a second O-shaped magnetic core and a third O-shaped magnetic core are sequentially fixed to the heat conduction plate side by side, each side column of the first O-shaped magnetic core is sleeved with a first framework, each side column of the second O-shaped magnetic core is sleeved with a second framework, each side column of the third O-shaped magnetic core is sleeved with a third framework, and the first framework and the second framework are sequentially fixed to the heat conduction plate. Secondary windings which are connected end to end are wound around each first framework and each second framework, a fourth framework is sleeved on the secondary windings wound around the second frameworks, primary windings which are connected end to end are wound around each third framework and each fourth framework, and an insulating layer is coated on the first O-shaped magnetic core, the second O-shaped magnetic core and the third O-shaped magnetic core; the linear inductors are respectively connected in series at two ends of the primary winding and the secondary winding to obtain excitation inductance, so that excitation inrush current is inhibited, the direct current magnetic bias phenomenon is improved, the assembly is convenient, and the space utilization rate is high.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power devices and relates to a bias magnetic suppression transformer. Background Art

[0002] The dual active bridge (DAB) converter is an isolated bidirectional DC-DC converter that can achieve power transmission and conversion between two ports. It has the characteristics of high control flexibility and good power supply reliability. The transformer it contains can not only achieve complete isolation and voltage matching between ports, but also reduce the size and weight of the device. However, in the application of the transformer, due to various reasons, the transformer will cause DC bias magnetic phenomenon, which will lead to reduced transformer efficiency, increased current stress of the power switch tube, and corresponding increase in switching loss. In severe cases, it may cause damage to the switching device.

[0003] Nanocrystalline materials have the characteristics of high magnetic permeability, low loss density and high saturation flux density. They are often used as the core of transformers. Their power density can reach three times that of traditional ferrite transformers. However, nanocrystalline cores are prone to DC bias in transformers. The DC bias current will cause the magnetization curve of the core to no longer be symmetrical about the origin when it is working. When the bias is serious, the core will enter unidirectional deep saturation, the magnetization current will increase dramatically, and the core loss and temperature rise will increase. Nanocrystalline cores can only be designed for use under low flux density, resulting in material waste. Compared with the soft saturation of ferrite cores, the magnetic permeability of nanocrystalline cores will drop sharply when saturated, which will have a greater impact on the transformer.

[0004] Existing methods for suppressing DC bias magnetism: 1. Increasing the effective cross-sectional area of ​​the transformer core to make the transformer less likely to saturate. This method significantly reduces the power density and increases the cost. 2. Connecting a DC blocking capacitor in series on the primary side of the transformer to filter out the DC component in the primary current by using the DC blocking characteristics of the capacitor. However, since the capacitor is connected in series in the main power circuit, its working conditions are much more stringent than those of ordinary filter capacitors and coupling capacitors. Especially in high-power situations, the required capacity of the capacitor is very large, the current loss will increase sharply, and the reliability will be greatly reduced, thereby affecting the working efficiency and reliability of the entire power supply system. 3. Matching the power switch tube with the core. The imbalance of volt-seconds is mainly caused by the different storage time and conduction voltage drop of the two switch tubes. If the switch tube parameters are matched, there will be no bias magnetism. However, the load size and operating temperature changes of the core cannot always match the switch tube parameters. In addition, the storage time is affected by the forward and reverse base input currents in the switch tube. The storage time is difficult to accurately match, and special test instruments are required for testing, which is costly. Based on the above status, corresponding solutions must be taken to the problem of DC bias magnetism. Summary of the invention

[0005] The purpose of the present invention is to provide a bias suppression transformer, which solves the problem in the prior art that the nanocrystalline magnetic core used as the magnetic core of the transformer is prone to generate DC bias.

[0006] The scheme adopted by the present invention is to suppress the bias magnetic transformer, including a heat conducting plate, on which a first O-type magnetic core, a second O-type magnetic core, and a third O-type magnetic core are fixed side by side in sequence, a first frame is sleeved on each side column of the first O-type magnetic core, a second frame is sleeved on each side column of the second O-type magnetic core, and a third frame is sleeved on each side column of the third O-type magnetic core. A secondary winding connected end to end is arranged around each first frame and each second frame, a fourth frame is sleeved on the secondary winding wound on the second frame, and a primary winding connected end to end is arranged around each third frame and each fourth frame, and an insulating layer is arranged to cover the first O-type magnetic core, the second O-type magnetic core, and the third O-type magnetic core.

[0007] The present invention is also characterized in that: The first O-shaped magnetic core and the third O-shaped magnetic core are both formed by splicing two U-shaped ferrite magnetic cores, and the first frame and the third frame are both sleeved at the splicing position of the corresponding two U-shaped ferrite magnetic cores.

[0008] The first O-shaped magnetic core and the third O-shaped magnetic core are both formed by stacking a plurality of magnetic blocks.

[0009] The second O-shaped magnetic core is formed by splicing a plurality of O-shaped nanocrystalline magnetic cores.

[0010] Two hanging ears are arranged oppositely on the top of the epoxy resin sealing glue layer, and through holes are opened on the hanging ears.

[0011] A first epoxy resin plate is fixed between the first O-shaped magnetic core and the second O-shaped magnetic core, and a second epoxy resin plate is fixed between the second O-shaped magnetic core and the third O-shaped magnetic core.

[0012] A clamping plate is fixed on both sides of the second O-shaped magnetic core on the upper surface of the heat conducting plate, and a plurality of bolts are fixed on the upper surface of the heat conducting plate.

[0013] The tops of the secondary windings wound on the two first skeletons are commonly connected to the first copper bar, and the first copper bar is sleeved with a first insulator; the tops of the secondary windings wound on the two second skeletons are commonly connected to the second copper bar, and the second copper bar is sleeved with a second insulator; the tops of the primary windings wound on the two third skeletons are commonly connected to the third copper bar, and the third copper bar is sleeved with a third insulator; the tops of the primary windings wound on the two fourth skeletons are commonly connected to the fourth copper bar, and the fourth copper bar is sleeved with a fourth insulator; the first insulator, the second insulator, the third insulator and the fourth insulator are all located outside the insulating layer.

[0014] The insulation layer is an epoxy resin sealing layer, and both the primary winding and the secondary winding use fully transposed Litz wire.

[0015] The beneficial effects of the present invention are: The invention suppresses magnetic bias transformer by connecting a linear inductor in series at both ends of the primary winding and the secondary winding to obtain the exciting inductance, thereby suppressing the exciting inrush current and improving the DC magnetic bias phenomenon. The transformer can be made into an integrated structure, which is convenient to assemble and has high space utilization. The exciting inductance is not obtained by increasing the air gap in the magnetic circuit of the nanocrystalline core, thereby eliminating the edge effect caused by the air gap part of the nanocrystalline core, reducing the loss caused by the edge effect, and solving the problem of temperature increase of the nanocrystalline core. Compared with the transformer that is not connected in series, the resistance of the primary winding and the secondary winding is increased. When the volt-second number is unbalanced, the coil The resistor can prevent the nanocrystalline core from saturating quickly. The winding with a larger volt-second value flows through a larger peak current. This current increases the voltage drop of the winding, reduces the volt-second value of the winding, and thus restores the current balance. The excitation inductance can be adjusted by suppressing the linear inductance outside the bias transformer, and the adaptation and modification of the leakage inductance is more flexible. The bias transformer is suitable for the situation where the primary winding and the secondary winding are both low voltage, and for the situation where both sides are high voltage. It is also suitable for the environment where one side is high voltage and the other side is low voltage. It can be adapted according to the insulation structure of the winding. The main magnetic core selects uncut nanocrystalline cores. Crystal cores and nanocrystalline cores have the characteristics of high magnetic permeability, low loss density and high saturation flux density, which improve the transmission efficiency of the bias suppression transformer, help reduce the volume of the bias suppression transformer, reduce the amount of wire used in the winding, and reduce costs; the series inductor core of the bias suppression transformer is composed of two U-shaped ferrite cores or multiple magnetic blocks are stacked into a matching shape. The core raw materials are extensive and low in price. There are air gaps in the spliced ​​parts of the core, and the air gaps can adjust the inductance; both the primary winding and the secondary winding use fully transposed Litz wire to reduce the skin effect and Proximity effect, reducing high-frequency AC loss of windings. Both the primary winding and the secondary winding are connected in parallel, which can reduce current density and increase overall space utilization. When the primary winding of the bias transformer is connected to the AC source generated by the power electronic conversion module, alternating magnetic flux will be generated in the magnetic core, thereby generating an alternating magnetic field, and the secondary winding will generate an induced electromotive force, completing the energy transfer and realizing the conversion of electric energy with one electrical characteristic into electric energy with another electrical characteristic, centrally realizing the functions of electrical isolation, voltage conversion, reactive power compensation, power transmission and control, and bidirectional energy flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an internal structure diagram of the bias magnetic suppression transformer of the present invention; Figure 2 It is an external structural diagram of the bias magnetic suppression transformer of the present invention; Figure 3 It is a splicing structure diagram of a U-shaped ferrite core in a bias suppression transformer of the present invention; Figure 4This is a diagram of the stacking structure of magnetic blocks in the bias magnetic suppression transformer of the present invention; Figure 5 This is a diagram of the splicing structure of the O-type nanocrystalline magnetic core in the bias suppression transformer of the present invention; Figure 6 is a top view of the internal structure of the bias magnetic suppression transformer of the present invention; Figure 7 It is a working connection diagram of the bias magnetic suppression transformer of the present invention; Figure 8 It is a connection diagram of the bias magnetic suppression transformer and the power electronic conversion module of the present invention.

[0017] In the figure, 1. first O-type magnetic core, 2. second O-type magnetic core, 3. third O-type magnetic core, 4. first frame, 5. second frame, 6. third frame, 7. secondary winding, 8. U-shaped ferrite core, 9. fourth frame, 10. primary winding, 11. magnetic block, 12. insulating layer, 13. O-type nanocrystalline core, 14. ear, 15. through hole, 16. card board, 17. bolt, 18. first epoxy resin board, 19. second epoxy resin board, 20. heat conducting plate, 21. first copper bar, 22. first insulator, 23. second copper bar, 24. second insulator, 25. third copper bar, 26. third insulator, 27. fourth copper bar, 28. fourth insulator. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Suppressing bias transformer, refer to Figure 1 , including a heat conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side, and the heat conducting plate 20 is used to transfer and suppress the heat generated by the bias transformer, a first skeleton 4 is sleeved on each side column of the first O-type magnetic core 1, a second skeleton 5 is sleeved on each side column of the second O-type magnetic core 2, and a third skeleton 6 is sleeved on each side column of the third O-type magnetic core 3, and a secondary winding 7 connected end to end is arranged around each first skeleton 4 and each second skeleton 5, and the secondary winding 7 is isolated from the second O-type magnetic core 2 by the second skeleton 5 to reduce the eddy current loss caused by scattered magnetic flux, and a fourth skeleton 9 is sleeved on the secondary winding 7 wound on the second skeleton 5, and a primary winding 10 connected end to end is arranged around each third skeleton 6 and each fourth skeleton 9, and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3.

[0020] Reference Figure 3 The first O-type magnetic core 1 and the third O-type magnetic core 3 are both formed by splicing two U-type ferrite cores 8 , and the first frame 4 and the third frame 6 are both sleeved at the splicing of the corresponding two U-type ferrite cores 8 .

[0021] Reference Figure 4 The first O-type magnetic core 1 and the third O-type magnetic core 3 are both composed of a plurality of stacked magnetic blocks 11, which can flexibly adjust the leakage inductance required by the overall transformer, and are distributed with air gaps. The air gaps can avoid the first O-type magnetic core 1 and the third O-type magnetic core 3 from being torn due to the inconsistent thermal expansion coefficients of the insulating layer 12 and the first O-type magnetic core 1 and the third O-type magnetic core 3, thereby ensuring the reliability of their electrical performance.

[0022] Reference Figure 5 The second O-type magnetic core 2 is composed of a plurality of O-type nanocrystalline magnetic cores 13 spliced ​​together.

[0023] Reference Figure 6 Two lifting ears 14 are relatively arranged on the top of the insulating layer 12, and a through hole 15 is opened on the lifting ear 14. The lifting ear 14 is used to lift the bias suppression transformer for easy transfer and transportation; a first epoxy resin plate 18 is fixed between the first O-type magnetic core 1 and the second O-type magnetic core 2, and a second epoxy resin plate 19 is fixed between the second O-type magnetic core 2 and the third O-type magnetic core 3. The first epoxy resin plate 18 and the second epoxy resin plate 19 can increase the insulation distance; a clamping plate 16 is fixed on both sides of the second O-type magnetic core 2 on the upper surface of the heat conducting plate 20, and a plurality of bolts 17 are fixed on the upper surface of the heat conducting plate 20. The bolts 17 are convenient for fixing the bias suppression transformer.

[0024] Reference Figure 1 The top of the secondary winding 7 wound on the two first skeletons 4 is commonly connected to a first copper bar 21, and the first copper bar 21 is sleeved with a first insulator 22; the top of the secondary winding 7 wound on the two second skeletons 5 is commonly connected to a second copper bar 23, and the second copper bar 23 is sleeved with a second insulator 24; the top of the primary winding 10 wound on the two third skeletons 6 is commonly connected to a third copper bar 25, and the third copper bar 25 is sleeved with a third insulator 26; the top of the primary winding 10 wound on the two fourth skeletons 9 is commonly connected to a fourth copper bar 27, and the fourth copper bar 27 is sleeved with a fourth insulator 28; the first insulator 22, the second insulator 24, the third insulator 26, and the fourth insulator 28 are all located outside the insulating layer 12, and the insulator is used to increase the creepage distance between the winding and the corresponding magnetic core. The copper bar is connected inside the insulator to realize the electrical connection between the primary winding, the secondary winding, the high-voltage module, and the low-voltage module.

[0025] The insulating layer 12 is an epoxy resin sealing layer. When the insulating layer 12 is set, the epoxy resin glue is first prepared and then placed in a high-pressure potting mold for evacuation, and then potting is performed. The thermal conductivity of the epoxy resin glue is 2-3W (m·K) to ensure that heat is conducted out. After potting and curing, the withstand voltage level of the bias-suppressing transformer can be increased. The epoxy resin potting glue has an H level after curing, and a temperature resistance of not less than 180°C. Both the primary winding 10 and the secondary winding 7 use fully transposed Litz wire, which can reduce the skin effect and proximity effect at high frequencies, and reduce the high-frequency AC loss of the winding. The two sides of the wire package are used in parallel to reduce the coil current density and reduce the temperature rise and loss of the bias-suppressing transformer. The outer insulation level of the Litz wire is H level or higher, and the temperature resistance of the Litz wire is not less than 180°C.

[0026] The working principle of the present invention is: Reference Figure 7 The primary winding 10 and the secondary winding 7 are respectively connected to a power electronic conversion module, and the two power electronic conversion modules are commonly connected to a control module. Under the control of the control module, the power electronic conversion module converts the input industrial frequency AC signal into a high-frequency signal, and then inputs the high-frequency signal into the bias suppression transformer. The bias suppression transformer couples the high-frequency signal from the primary winding 10 to the secondary winding 7 according to the principle of electromagnetic induction, and then the power electronic conversion module converts it into a DC signal output, thereby realizing bidirectional transmission and energy transfer.

[0027] Reference Figure 8 The connection modes of the power electronic conversion module with the primary winding 10 and the secondary winding 7 are as follows: the primary winding 10 and the secondary winding 7 are respectively connected to a high-voltage module; the primary winding 10 is connected to a high-voltage module, and the secondary winding 7 is connected to a low-voltage module; the primary winding 10 and the secondary winding 7 are respectively connected to a low-voltage module; the primary winding 10 is connected to a low-voltage module, and the secondary winding 7 is connected to a high-voltage module.

[0028] Embodiment 1: A bias-suppressing transformer comprises a heat-conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side; a first frame 4 is sleeved on each side column of the first O-type magnetic core 1, a second frame 5 is sleeved on each side column of the second O-type magnetic core 2, and a third frame 6 is sleeved on each side column of the third O-type magnetic core 3; a secondary winding 7 connected end to end is arranged around each first frame 4 and each second frame 5; a fourth frame 9 is sleeved on the secondary winding 7 wound on the second frame 5; a primary winding 10 connected end to end is arranged around each third frame 6 and each fourth frame 9; and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3. The first O-type magnetic core 1 and the third O-type magnetic core 3 are both composed of two U-type ferrite cores 8 spliced ​​together. The first skeleton 4 and the third skeleton 6 are both sleeved at the joint of the corresponding two U-type ferrite cores 8. Two ears 14 are arranged on the top of the insulating layer 12, and a through hole 15 is opened on the ear 14. A first epoxy resin plate 18 is fixed between the first O-type magnetic core 1 and the second O-type magnetic core 2, and a second epoxy resin plate 19 is fixed between the second O-type magnetic core 2 and the third O-type magnetic core 3. The tops of the secondary windings 7 wound on the two first skeletons 4 are commonly connected to a first copper bar 21, and a first insulator 22 is sleeved on the first copper bar 21; the secondary windings 7 wound on the two second skeletons 5 are connected to the first copper bar 21. The first copper bar 21 is sleeved with a first insulator 22. The top of the secondary winding 7 is commonly connected to a second copper bar 23, and the second copper bar 23 is sleeved with a second insulator 24; the top of the primary winding 10 wound on the two third skeletons 6 is commonly connected to a third copper bar 25, and the third copper bar 25 is sleeved with a third insulator 26; the top of the primary winding 10 wound on the two fourth skeletons 9 is commonly connected to a fourth copper bar 27, and the fourth copper bar 27 is sleeved with a fourth insulator 28; the first insulator 22, the second insulator 24, the third insulator 26, and the fourth insulator 28 are all located outside the insulating layer 12, the insulating layer 12 is an epoxy resin sealing layer, and the primary winding 10 and the secondary winding 7 both use fully transposed Litz wire.

[0029] Embodiment 2: A bias-suppressing transformer comprises a heat-conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side; a first frame 4 is sleeved on each side column of the first O-type magnetic core 1, a second frame 5 is sleeved on each side column of the second O-type magnetic core 2, and a third frame 6 is sleeved on each side column of the third O-type magnetic core 3; a secondary winding 7 connected end to end is arranged around each first frame 4 and each second frame 5; a fourth frame 9 is sleeved on the secondary winding 7 wound on the second frame 5; a primary winding 10 connected end to end is arranged around each third frame 6 and each fourth frame 9; and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3.

[0030] The first O-type magnetic core 1 and the third O-type magnetic core 3 are both composed of 8 stacked magnetic blocks 11, two ears 14 are arranged on the top of the insulating layer 12, and a through hole 15 is opened on the ear 14; a first epoxy resin plate 18 is fixed between the first O-type magnetic core 1 and the second O-type magnetic core 2, a second epoxy resin plate 19 is fixed between the second O-type magnetic core 2 and the third O-type magnetic core 3, a clamping plate 16 is fixed on both sides of the second O-type magnetic core 2 on the upper surface of the heat conducting plate 20, and 10 bolts 17 are fixed on the upper surface of the heat conducting plate 20, and the top of the secondary winding 7 wound on the two first skeletons 4 is commonly connected to the first copper bar 21, and the first copper bar 21 A first insulator 22 is sleeved on the upper part; a second copper bar 23 is commonly connected to the top of the secondary winding 7 wound on the two second skeletons 5, and a second insulator 24 is sleeved on the second copper bar 23; a third copper bar 25 is commonly connected to the top of the primary winding 10 wound on the two third skeletons 6, and a third insulator 26 is sleeved on the third copper bar 25; a fourth copper bar 27 is commonly connected to the top of the primary winding 10 wound on the two fourth skeletons 9, and a fourth insulator 28 is sleeved on the fourth copper bar 27; the first insulator 22, the second insulator 24, the third insulator 26, and the fourth insulator 28 are all located outside the insulating layer 12.

[0031] Embodiment 3: A bias-suppressing transformer comprises a heat-conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side; a first frame 4 is sleeved on each side column of the first O-type magnetic core 1, a second frame 5 is sleeved on each side column of the second O-type magnetic core 2, and a third frame 6 is sleeved on each side column of the third O-type magnetic core 3; a secondary winding 7 connected end to end is arranged around each first frame 4 and each second frame 5; a fourth frame 9 is sleeved on the secondary winding 7 wound on the second frame 5; a primary winding 10 connected end to end is arranged around each third frame 6 and each fourth frame 9; and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3.

[0032] The second O-type magnetic core 2 is composed of four O-type nanocrystalline magnetic cores 13 spliced ​​together. The tops of the secondary windings 7 wound on the two first skeletons 4 are commonly connected to the first copper bar 21, and the first copper bar 21 is sleeved with a first insulator 22; the tops of the secondary windings 7 wound on the two second skeletons 5 are commonly connected to the second copper bar 23, and the second copper bar 23 is sleeved with a second insulator 24; the tops of the primary windings 10 wound on the two third skeletons 6 are commonly connected to the third copper bar 25, and the third copper bar 25 is sleeved with a third insulator 26; the tops of the primary windings 10 wound on the two fourth skeletons 9 are commonly connected to the fourth copper bar 27, and the fourth copper bar 27 is sleeved with a fourth insulator 28; the first insulator 22, the second insulator 24, the third insulator 26, and the fourth insulator 28 are all located outside the insulating layer 12, the insulating layer 12 is an epoxy resin sealing layer, and the primary winding 10 and the secondary winding 7 both use fully transposed Litz wires.

[0033] Embodiment 4: A bias-suppressing transformer comprises a heat-conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side; a first frame 4 is sleeved on each side column of the first O-type magnetic core 1, a second frame 5 is sleeved on each side column of the second O-type magnetic core 2, and a third frame 6 is sleeved on each side column of the third O-type magnetic core 3; a secondary winding 7 connected end to end is arranged around each first frame 4 and each second frame 5; a fourth frame 9 is sleeved on the secondary winding 7 wound on the second frame 5; a primary winding 10 connected end to end is arranged around each third frame 6 and each fourth frame 9; and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3.

[0034] The first O-type magnetic core 1 and the third O-type magnetic core 3 are both composed of two U-type ferrite cores 8 spliced ​​together, the first skeleton 4 and the third skeleton 6 are both sleeved on the corresponding joints of the two U-type ferrite cores 8, the second O-type magnetic core 2 is composed of five O-type nanocrystalline magnetic cores 13 spliced ​​together, two ears 14 are relatively arranged on the top of the insulating layer 12, and a through hole 15 is opened on the ear 14; a first epoxy resin plate 18 is fixed between the first O-type magnetic core 1 and the second O-type magnetic core 2, a second epoxy resin plate 19 is fixed between the second O-type magnetic core 2 and the third O-type magnetic core 3, a clamping plate 16 is fixed on both sides of the second O-type magnetic core 2 on the upper surface of the heat conducting plate 20, and 8 bolts 17 are fixed on the upper surface of the heat conducting plate 20.

[0035] Embodiment 5: A bias-suppressing transformer comprises a heat-conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side; a first frame 4 is sleeved on each side column of the first O-type magnetic core 1, a second frame 5 is sleeved on each side column of the second O-type magnetic core 2, and a third frame 6 is sleeved on each side column of the third O-type magnetic core 3; a secondary winding 7 connected end to end is arranged around each first frame 4 and each second frame 5; a fourth frame 9 is sleeved on the secondary winding 7 wound on the second frame 5; a primary winding 10 connected end to end is arranged around each third frame 6 and each fourth frame 9; and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3.

[0036] The first O-type magnetic core 1 and the third O-type magnetic core 3 are both composed of 6 stacked magnetic blocks 11, the second O-type magnetic core 2 is composed of 5 O-type nanocrystalline magnetic cores 13, a clamping plate 16 is fixed on both sides of the second O-type magnetic core 2 on the upper surface of the heat conducting plate 20, 12 bolts 17 are fixed on the upper surface of the heat conducting plate 20, the top of the secondary winding 7 wound on the two first skeletons 4 is commonly connected to the first copper bar 21, and the first copper bar 21 is sleeved with a first insulator 22; the top of the secondary winding 7 wound on the two second skeletons 5 is commonly connected to A second copper bar 23 is connected, and a second insulator 24 is sleeved on the second copper bar 23; the tops of the primary windings 10 wound on the two third skeletons 6 are commonly connected to a third copper bar 25, and a third insulator 26 is sleeved on the third copper bar 25; the tops of the primary windings 10 wound on the two fourth skeletons 9 are commonly connected to a fourth copper bar 27, and a fourth insulator 28 is sleeved on the fourth copper bar 27; the first insulator 22, the second insulator 24, the third insulator 26, and the fourth insulator 28 are all located outside the insulating layer 12.

[0037] Embodiment 6: A bias-suppressing transformer comprises a heat-conducting plate 20, on which a first O-type magnetic core 1, a second O-type magnetic core 2, and a third O-type magnetic core 3 are fixed in sequence and side by side; a first frame 4 is sleeved on each side column of the first O-type magnetic core 1, a second frame 5 is sleeved on each side column of the second O-type magnetic core 2, and a third frame 6 is sleeved on each side column of the third O-type magnetic core 3; a secondary winding 7 connected end to end is arranged around each first frame 4 and each second frame 5; a fourth frame 9 is sleeved on the secondary winding 7 wound on the second frame 5; a primary winding 10 connected end to end is arranged around each third frame 6 and each fourth frame 9; and an insulating layer 12 is arranged to cover the first O-type magnetic core 1, the second O-type magnetic core 2, and the third O-type magnetic core 3.

[0038] The second O-type magnetic core 2 is composed of three O-type nanocrystalline magnetic cores 13. Two ears 14 are arranged on the top of the insulating layer 12. The ears 14 are provided with through holes 15. The tops of the secondary windings 7 wound on the two first skeletons 4 are connected to the first copper bar 21. The first copper bar 21 is sleeved with a first insulator 22. The tops of the secondary windings 7 wound on the two second skeletons 5 are connected to the second copper bar 23. The second copper bar 23 is sleeved with a second insulator 24. The secondary windings 7 wound on the two third skeletons 6 are connected to the second copper bar 23. The top of the primary winding 10 is commonly connected to a third copper bar 25, and the third copper bar 25 is sleeved with a third insulator 26; the top of the primary winding 10 wound on two fourth skeletons 9 is commonly connected to a fourth copper bar 27, and the fourth copper bar 27 is sleeved with a fourth insulator 28; the first insulator 22, the second insulator 24, the third insulator 26, and the fourth insulator 28 are all located outside the insulating layer 12, and the insulating layer 12 is an epoxy resin sealing layer. The primary winding 10 and the secondary winding 7 both use fully transposed Litz wire.

Claims

1. A bias suppression transformer, characterized in that: The invention comprises a heat conducting plate (20), on which a first O-type magnetic core (1), a second O-type magnetic core (2), and a third O-type magnetic core (3) are fixed in parallel in sequence, each side column of the first O-type magnetic core (1) is sleeved with a first frame (4), each side column of the second O-type magnetic core (2) is sleeved with a second frame (5), and each side column of the third O-type magnetic core (3) is sleeved with a third frame (6), a secondary winding (7) connected end to end is arranged around each of the first frames (4) and each of the second frames (5), a fourth frame (9) is sleeved on the secondary winding (7) wound on the second frame (5), a primary winding (10) connected end to end is arranged around each of the third frames (6) and each of the fourth frames (9), and an insulating layer (12) is arranged to cover the first O-type magnetic core (1), the second O-type magnetic core (2), and the third O-type magnetic core (3).

2. The bias suppression transformer according to claim 1, characterized in that: The first O-shaped magnetic core (1) and the third O-shaped magnetic core (3) are both formed by splicing two U-shaped ferrite magnetic cores (8), and the first frame (4) and the third frame (6) are both sleeved on the splicing positions of the corresponding two U-shaped ferrite magnetic cores (8).

3. The bias suppression transformer according to claim 1, characterized in that: The first O-type magnetic core (1) and the third O-type magnetic core (3) are both composed of a plurality of stacked magnetic blocks (11).

4. The bias suppression transformer according to claim 1, characterized in that: The second O-type magnetic core (2) is formed by splicing a plurality of O-type nanocrystalline magnetic cores (13).

5. The bias suppression transformer according to any one of claims 1 to 4, characterized in that: Two lifting ears (14) are arranged opposite to each other on the top of the insulating layer (12), and a through hole (15) is provided on the lifting ears (14).

6. The bias suppression transformer according to any one of claims 1 to 4, characterized in that: A first epoxy resin plate (18) is fixed between the first O-shaped magnetic core (1) and the second O-shaped magnetic core (2), and a second epoxy resin plate (19) is fixed between the second O-shaped magnetic core (2) and the third O-shaped magnetic core (3).

7. The bias suppression transformer according to any one of claims 1 to 4, characterized in that: A clamping plate (16) is fixed to each side of the second O-shaped magnetic core (2) on the upper surface of the heat conducting plate (20), and a plurality of bolts (17) are fixed to the upper surface of the heat conducting plate (20).

8. The bias suppression transformer according to any one of claims 1 to 4, characterized in that: The tops of the secondary windings (7) wound on the two first frames (4) are commonly connected to a first copper bar (21), and a first insulator (22) is sleeved on the first copper bar (21); the tops of the secondary windings (7) wound on the two second frames (5) are commonly connected to a second copper bar (23), and a second insulator (24) is sleeved on the second copper bar (23); the tops of the primary windings (10) wound on the two third frames (6) are commonly connected to a third copper bar (25), and a third insulator (26) is sleeved on the third copper bar (25); the tops of the primary windings (10) wound on the two fourth frames (9) are commonly connected to a fourth copper bar (27), and a fourth insulator (28) is sleeved on the fourth copper bar (27); the first insulator (22), the second insulator (24), the third insulator (26), and the fourth insulator (28) are all located outside the insulating layer (12).

9. The bias suppression transformer according to any one of claims 1 to 4, characterized in that: The insulating layer (12) is an epoxy resin sealing layer, and the primary winding (10) and the secondary winding (7) both use fully transposed Litz wires.

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