Transformer core design method and transformer

Abstract

The present invention discloses a transformer core design method and a transformer, relating to the technical field of transformers. The method includes: determining the pitch of the stranded wire used for winding the transformer winding; determining the core required for the transformer to be designed according to the core area of the transformer to be designed and the pitch; wherein, the core area of the core is equal to the core area of the transformer to be designed, and the window depth of the core is an integer multiple of the pitch. The beneficial effects of the present invention are as follows: taking into account the influence between the windings within the layer and between different strands of the multi-strand litz wire, thereby being able to significantly reduce the proximity effect resistance, reduce the resistance loss, and improve the efficiency of the transformer.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformers, and particularly relates to a design method for a transformer core and a transformer. Background Art

[0002] In electrical engineering, when designing a high-frequency transformer, it is necessary to consider the proximity effect and skin effect on the transformer. Often, in order to reduce the proximity effect of the transformer, it is considered to set the primary winding and the secondary winding in a cross-over manner. However, this setting method only considers the proximity effect between the primary winding and the secondary winding, and does not consider the proximity effect within the layer. Therefore, it is necessary to propose a better design method for a transformer core to reduce the proximity effect. Summary of the Invention

[0003] Based on the technical problem that the existing technology of setting the primary winding and the secondary winding in a cross-over manner cannot reduce the proximity effect within the layer, the present invention proposes a design method for a transformer core and a transformer.

[0004] In a first aspect, an embodiment of the present invention provides a design method for a transformer core, including:

[0005] Determine the pitch of the stranded wire for winding the transformer winding;

[0006] According to the core area of the transformer to be designed and the pitch, determine the core required for the transformer to be designed; wherein, the core area of the core is equal to the core area of the transformer to be designed, and the window depth of the core is an integer multiple of the pitch.

[0007] Optionally, before determining the core required for the transformer to be designed according to the core area of the transformer to be designed and the pitch, the method further includes:

[0008] Determine the apparent power of the transformer to be designed;

[0009] According to the apparent power, determine the core area of the transformer to be designed.

[0010] Optionally, determining the apparent power of the transformer to be designed includes:

[0011] Determine the input power and output power of the transformer to be designed;

[0012] According to the input power and the output power, determine the apparent power of the transformer to be designed.

[0013] Optionally, according to the input power and the output power, determining the apparent power of the transformer to be designed includes:

[0014] According to the input power and the output power, the apparent power is obtained by using a first pre-designed formula; wherein, the first pre-designed formula includes:

[0015] P t = P1 + P2

[0016] wherein, P t is the apparent power, P1 is the input power, and P2 is the output power.

[0017] Optionally, according to the apparent power, determining the core area of the transformer to be designed includes:

[0018] Calculating according to the apparent power by using a second pre-designed formula to obtain the core area of the transformer to be designed; wherein, the second pre-designed formula includes:

[0019]

[0020] wherein, AP is the core area of the transformer to be designed, P t is the apparent power, K W is the window utilization factor, K f is the form factor, J is the current density, B m is the working magnetic flux density, and f is the frequency.

[0021] Optionally, before determining the pitch of the stranded wire for winding the transformer winding, the method further includes:

[0022] Determining the output power and output voltage of the transformer to be designed;

[0023] According to the output power and output voltage of the transformer to be designed, determining the cross-sectional area of the stranded wire for winding the transformer winding;

[0024] Selecting the stranded wire meeting the cross-sectional area from alternative stranded wires, and determining the pitch of the stranded wire for winding the transformer winding according to the specification corresponding to the selected stranded wire.

[0025] Optionally, according to the output power and output voltage of the transformer to be designed, determining the cross-sectional area of the stranded wire for winding the transformer winding includes:

[0026] Calculating according to the output power and output voltage of the transformer to be designed by using a third pre-designed formula to obtain the cross-sectional area of the stranded wire for winding the transformer winding; wherein, the third pre-designed formula includes:

[0027]

[0028] Among them, A2 is the cross-sectional area of the stranded wire, P2 is the output power of the transformer to be designed, V2 is the output voltage of the transformer to be designed, and J is the current density.

[0029] Optionally, after determining the magnetic core required for the transformer to be designed according to the magnetic core area and the pitch of the transformer to be designed, the method further includes:

[0030] According to the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed, wind the stranded wire around the magnetic core according to the number of turns of the primary winding and the number of turns of the secondary winding required, to obtain the designed transformer.

[0031] Optionally, after determining the magnetic core required for the transformer to be designed according to the magnetic core area and the pitch of the transformer to be designed, the method further includes:

[0032] Determine the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed, so as to wind the stranded wire around the magnetic core according to the number of turns of the primary winding and the number of turns of the secondary winding.

[0033] Optionally, determining the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed; includes:

[0034] Determine the input voltage of the primary winding and the output voltage of the secondary winding of the transformer to be designed;

[0035] According to the input voltage of the primary winding, calculate using a fourth preliminary design formula to obtain the number of turns of the primary winding; where, the fourth preliminary design formula includes:

[0036]

[0037] Among them, N1 is the number of turns of the primary winding, K f is the form factor, B m is the working magnetic flux density, A e is the cross-sectional area of the magnetic core, f is the frequency, V1 is the input voltage of the primary winding; and

[0038] According to the input voltage of the primary winding, the output voltage of the secondary winding and the number of turns of the primary winding, calculate using a fifth preliminary design formula to obtain the number of turns of the secondary winding; where, the fifth preliminary design formula includes:

[0039]

[0040] Among them, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, V1 is the input voltage of the primary winding, and V2 is the output voltage of the secondary winding.

[0041] Optionally, the stranded wire is obtained by stranding at least two Litz wires.

[0042] In a second aspect, an embodiment of the present invention further provides a transformer, which is manufactured by using the transformer core design method described in any one of the above embodiments.

[0043] In a transformer core design method provided by an embodiment of the present invention, by setting the window depth of the core of the transformer to an integer multiple of the pitch of the stranded wire used for winding the transformer winding, when winding the winding, the winding length of the stranded wire winding in the core will be an integer multiple of the pitch of the stranded wire, thereby being able to suppress the proximity effect between the windings within the layer. Considering the influence between the windings within the layer and between different strands of multiple Litz wires, it is possible to significantly reduce the proximity effect resistance, reduce the resistance loss, and improve the efficiency of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The scope of the present disclosure can be better understood by reading the detailed description of the exemplary embodiments below in conjunction with the accompanying drawings. The accompanying drawings included are:

[0045] Figure 1 A flowchart showing a transformer core design method proposed in Embodiment 1 of the present invention;

[0046] Figure 2 A schematic diagram showing the proximity effect;

[0047] Figure 3 A schematic diagram showing the stranded wire;

[0048] Figure 4 A flowchart showing a transformer core design method proposed in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will describe in detail the implementation methods of the present invention in conjunction with the accompanying drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly.

[0050] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0051] Example 1

[0052] According to an embodiment of the present invention, a transformer core design method is provided. Figure 1The flowchart of a transformer core design method proposed in Embodiment 1 of the present invention is shown. As Figure 1 shown, the transformer core design method may include: Step 110 to Step 120.

[0053] In Step 110, determine the pitch of the stranded wire for winding the transformer winding.

[0054] Here, the stranded wire is obtained by stranding at least two Litz wires, that is, the stranded wire is stranded together by at least two Litz wires in a certain direction and with a certain pitch. Among them, the stranded wire for winding the transformer winding refers to the stranded wire of the conductor used for the winding of the transformer to be designed.

[0055] In one embodiment, the stranded wire can be obtained through Step 111 to Step 113:

[0056] In Step 111, determine the output power and output voltage of the transformer to be designed.

[0057] Here, the output power and output voltage of the transformer can be obtained according to the actual requirements of the transformer to be designed.

[0058] In Step 112, according to the output power and output voltage of the transformer to be designed, determine the cross-sectional area of the stranded wire for winding the transformer winding.

[0059] In an optional embodiment, according to the output power and output voltage of the transformer to be designed, calculate using a third preliminary design formula to obtain the cross-sectional area of the stranded wire for winding the transformer winding; where the third preliminary design formula includes:

[0060]

[0061] Among them, A2 is the cross-sectional area of the stranded wire, P2 is the output power of the transformer to be designed, V2 is the output voltage of the transformer to be designed, and J is the current density.

[0062] In Step 113, select the stranded wire that meets the cross-sectional area from the alternative stranded wires, and determine the pitch of the stranded wire for winding the transformer winding according to the specifications corresponding to the selected stranded wire.

[0063] Here, since the stranded wire is stranded together by multiple Litz wires in a certain direction and with a certain rule, after selecting the stranded wire with a cross-sectional area that meets the requirements, the pitch of the stranded wire for winding the transformer winding can be obtained according to the specifications of the stranded wire.

[0064] In addition, the skin effect needs to be considered when selecting the stranded wire, so as to determine the wire diameter of each single Litz wire in the selected stranded wire. That is, the cross-sectional area of the selected stranded wire should meet the requirements, and the wire diameter of each single Litz wire in the stranded wire should also meet the requirements. The wire diameter of each single Litz wire can be determined by the following method:

[0065] Use the calculation formula to calculate the skin depth of the wire. Here, Δ is the skin depth, μ0 is the magnetic permeability of the wire, ρ is the resistivity, and f s is the electromagnetic wave frequency. Among them, the electromagnetic wave frequency f s is equal to the frequency f.

[0066] The wire diameter d of each single Litz wire in the stranded wire is less than 2Δ, and generally, Litz wire with a wire diameter of 0.59 is selected.

[0067] In step 120, according to the core area of the transformer to be designed and the pitch, determine the core required for the transformer to be designed; among them, the core area of the core is equal to the core area of the transformer to be designed, and the window depth of the core is an integer multiple of the pitch.

[0068] Here, the core area AP refers to the product of the cross-sectional area A e of the core and the window area A w . After calculating the core area required for the transformer to be designed, by querying the core table, select the core that meets the required core area from the core table, that is, the core area of the selected core needs to be equal to the calculated core area of the transformer to be designed.

[0069] Moreover, when selecting the core, the core area of the selected core not only meets the requirements of the core area required for the transformer to be designed, but also the window depth of the selected core should be an integer multiple of the pitch of the stranded wire used for winding the transformer winding, so that the winding length of the stranded wire on the core is an integer multiple of the pitch, in order to reduce the proximity effect of the transformer. For example, if the pitch is 0.2 mm, the window depth can be 100 times 2 cm.

[0070] It should be noted that if the core parameters meeting the above requirements cannot be found in the core table, the core meeting the above requirements can be designed and manufactured by oneself.

[0071] Among them, the proximity effect refers to that when alternating currents flow through conductors close to each other, each conductor is not only in the electromagnetic field generated by its own current, but also in the electromagnetic field generated by the current in other conductors. At this time, the current distribution in each conductor will be affected by the adjacent conductors, and this phenomenon is called the proximity effect.

[0072] Figure 2The schematic diagram showing the proximity effect is as follows Figure 2 As shown, for wire 1, under the influence of the alternating magnetic field generated by wire 2, the charges in wire 1 are forced to move to the left, so the current density on the left side of wire 1 is relatively large. This non-uniform current distribution will lead to a relatively large wire resistance for wire 1. Similarly, wire 2 is affected by the magnetic field generated by wire 1, resulting in a relatively large current density on the right side.

[0073] Figure 3 The schematic diagram showing the stranded wire is as follows Figure 3 As shown, multiple wires are stranded to form a stranded wire. When wire 1 and wire 2 are stranded together, that is, wire 1 and wire 2 form a stranded wire, within one pitch period, the current density on the left side of wire 1 is large in the first half period and the current density on the right side is large in the second half period. Considering the comprehensive effect, the current density distribution will be more uniform compared to the winding formed without stranding. Obviously, this stranding method will, to a certain extent, reduce the non-uniform current distribution phenomenon, suppress the influence of the proximity effect, and further reduce the problem of increased wire resistance caused by the proximity effect. Since the magnetic field affecting the proximity effect in the inner region of the magnetic core where the winding is located is relatively strong, in the present invention, the window depth of the magnetic core is set to an integer multiple of the pitch of the stranded wire, so that the winding length of the stranded wire winding in the magnetic core will be an integer multiple of the pitch of the stranded wire, thereby reducing the influence of the proximity effect.

[0074] In an alternative embodiment, the magnetic core area of the transformer to be designed can be obtained through the following steps:

[0075] Step 121, determine the apparent power of the transformer to be designed.

[0076] Specifically, this step is to determine the input power and output power of the transformer to be designed; based on the input power and the output power, determine the apparent power of the transformer to be designed.

[0077] Here, the input power and output power of the transformer to be designed are determined according to the specifications of the transformer designed according to actual needs.

[0078] Among them, the apparent power can be obtained through the calculation formula P t = P1 + P2, where P t is the apparent power, P1 is the input power, and P2 is the output power.

[0079] The apparent power can also be obtained using the calculation formula where P t is the apparent power, η is the efficiency, and P2 is the output power.

[0080] Step 122, based on the apparent power, determine the magnetic core area of the transformer to be designed.

[0081] Here, the core area AP refers to the cross-sectional area A of the core e and the window area A w product.

[0082] In one embodiment, a second pre-design formula can be used for calculation to obtain the core area of the transformer to be designed; wherein, the second pre-design formula includes:

[0083]

[0084] wherein, AP is the core area of the transformer to be designed, P t is the apparent power, K W is the window utilization factor, K f is the form factor, J is the current density, B m is the working magnetic flux density, and f is the frequency.

[0085] Here, the value of the window utilization factor K W can be 0.4. In the form factor K f , for a sine wave, the value is 4.44, for a rectangular wave, it is 4, the value of the working magnetic flux density is 0.2, and the value of the frequency f is 50 kHz.

[0086] In this embodiment, by setting the window depth of the core of the transformer to an integer multiple of the pitch of the stranded wire used to wind the transformer winding, when winding the winding, the winding length of the stranded wire winding in the core will be an integer multiple of the pitch of the stranded wire, thereby being able to suppress the proximity effect between the windings within the layer. Taking into account the influence between the windings within the layer and between different strands of multiple litz wires, it can thus greatly reduce the proximity effect resistance, reduce the resistance loss, and improve the transformer efficiency.

[0087] Example 2

[0088] Based on the above embodiment, Embodiment 2 of the present invention can further provide a method for designing a transformer core. Figure 4 Fig. shows a schematic flowchart of a method for designing a transformer core proposed in Embodiment 2 of the present invention. As Figure 4 shown, the method for designing a transformer core can include: Step 210 to Step 250.

[0089] Step 210, determining the apparent power of the transformer to be designed.

[0090] Specifically, this step can be to determine the input power and output power of the transformer to be designed; based on the input power and the output power, determine the apparent power of the transformer to be designed.

[0091] Here, the input power and output power of the transformer to be designed are determined according to the transformer required in the actual situation.

[0092] Among them, the apparent power is a quantity representing the capacity of an AC electrical equipment, equal to the product of the effective value of voltage and the effective value of current. The apparent power multiplied by the power factor is equal to the active power.

[0093] Among them, the apparent power can be obtained through the first pre-design formula P t = P1 + P2, where P t is the apparent power, P1 is the input power, and P2 is the output power.

[0094] The apparent power can also be obtained by using the calculation formula where P t is the apparent power, η is the efficiency, and P2 is the output power.

[0095] Step 220: Determine the core area of the transformer to be designed according to the apparent power.

[0096] Here, the core area AP refers to the product of the core cross-sectional area A e and the window area A w . In one embodiment, the second pre-design formula can be used for calculation to obtain the core area of the transformer to be designed; among them, the second pre-design formula includes:

[0097]

[0098] where AP is the core area of the transformer to be designed, P t is the apparent power, K W is the window utilization factor, K f is the form factor, J is the current density, B m is the working magnetic flux density, and f is the frequency.

[0099] Here, the value of the window utilization factor K W can be 0.4. In the form factor K f , for a sine wave, the value is 4.44, for a rectangular wave, it is 4, the value of the working magnetic flux density is 0.2, and the value of the frequency f is 50 kHz.

[0100] Step 230: Determine the pitch of the stranded wire used for winding the transformer winding.

[0101] Here, the stranded wire is the wire used to form the transformer winding. In the present invention, the stranded wire is formed by stranding multiple litz wires together in a certain direction and according to a certain rule. It is applicable to occasions where the skin effect and proximity effect losses of a single-strand wire are too large at a relatively high operating frequency. Using a stranded wire can reduce the operating temperature. Compared with a single-strand wire of the same cross-sectional area, the stranded wire has higher mechanical properties and flexibility.

[0102] In an alternative embodiment, the lay length of the stranded wire can be obtained through the following steps:

[0103] Determine the output power and output voltage of the transformer to be designed.

[0104] Here, the output power and output voltage of the transformer can be obtained according to the actual requirements of the transformer to be designed.

[0105] According to the output power and output voltage of the transformer to be designed, determine the cross-sectional area of the stranded wire used for winding the transformer winding.

[0106] Select a stranded wire that meets the cross-sectional area from the alternative stranded wires, and determine the lay length of the stranded wire used for winding the transformer winding according to the specifications corresponding to the selected stranded wire.

[0107] In an alternative embodiment, according to the output power and output voltage of the transformer to be designed, calculate using a third preliminary design formula to obtain the cross-sectional area of the stranded wire used for winding the transformer winding; wherein, the third preliminary design formula includes:

[0108]

[0109] wherein, A2 is the cross-sectional area of the stranded wire, P2 is the output power of the transformer to be designed, V2 is the output voltage of the transformer to be designed, and J is the current density.

[0110] Here, since the stranded wire is formed by stranding multiple litz wires together in a certain direction and according to a certain rule, after selecting a stranded wire with a qualified cross-sectional area, the lay length of the stranded wire used for winding the transformer winding can be obtained according to the specifications of the stranded wire.

[0111] In addition, the skin effect needs to be considered when selecting the stranded wire, so as to determine the wire diameter of a single litz wire in the selected stranded wire. That is, the cross-sectional area of the selected stranded wire should meet the requirements, and the wire diameter of a single litz wire in the stranded wire should also meet the requirements. The wire diameter of a single litz wire can be determined by the following method:

[0112] Use the calculation formula Calculate the skin depth of the wire, where Δ is the skin depth, μ0 is the magnetic permeability of the wire, ρ is the resistivity, and fs is the electromagnetic wave frequency. Among them, the electromagnetic wave frequency f s is equal to the frequency f.

[0113] The wire diameter d of a single-strand Litz wire of the stranded wire is < 2Δ, and generally a Litz wire with a wire diameter of 0.59 is selected.

[0114] Step 240: Determine the magnetic core required for the transformer to be designed according to the magnetic core area of the transformer to be designed and the pitch. Among them, the magnetic core area of the magnetic core is equal to the magnetic core area of the transformer to be designed, and the window depth of the magnetic core is an integer multiple of the pitch.

[0115] Here, after calculating the magnetic core area required for the transformer to be designed, by querying the magnetic core table, select the magnetic core that meets the required magnetic core area from the magnetic core table, that is, the magnetic core area of the selected magnetic core needs to be equal to the calculated magnetic core area of the transformer to be designed.

[0116] However, when selecting the magnetic core, the magnetic core area of the selected magnetic core not only meets the requirements of the magnetic core area required for the transformer to be designed, but also the window depth of the selected magnetic core is an integer multiple of the pitch of the stranded wire used to wind the transformer winding, so that the winding length of the stranded wire on the magnetic core is an integer multiple of the pitch, in order to reduce the proximity effect of the transformer. For example, if the pitch is 0.2 mm, the window depth can be 100 times 2 cm.

[0117] It should be noted that if the magnetic core parameters that meet the above requirements cannot be found in the magnetic core table, the magnetic core that meets the above requirements can be designed and molded by oneself.

[0118] In an optional embodiment, the magnetic core area of the transformer to be designed can be obtained through the following steps:

[0119] Determine the input power and output power of the transformer to be designed;

[0120] Here, the input power and output power of the transformer to be designed are determined according to the specifications of the transformer designed according to actual needs.

[0121] According to the input power and the output power, determine the apparent power of the transformer to be designed;

[0122] Here, the apparent power can be obtained through the calculation formula P t = P1 + P2, where P t is the apparent power, P1 is the input power, and P2 is the output power.

[0123] The apparent power can also be obtained by using the calculation formula where P tis the apparent power, η is the efficiency, and P2 is the output power.

[0124] Determine the core area of the transformer to be designed according to the apparent power.

[0125] Here, the core area AP refers to the product of the cross-sectional area A of the core e and the window area A w .

[0126] In one embodiment, a second preliminary design formula can be used for calculation to obtain the core area of the transformer to be designed; wherein, the second preliminary design formula includes:

[0127]

[0128] wherein, AP is the core area of the transformer to be designed, P t is the apparent power, K W is the window utilization factor, K f is the form factor, J is the current density, B m is the working magnetic flux density, and f is the frequency.

[0129] Step 250, determine the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed, so as to wind the stranded wire on the core according to the number of turns of the primary winding and the number of turns of the secondary winding.

[0130] Here, according to the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed, wind the stranded wire on the core according to the required number of turns of the primary winding and the number of turns of the secondary winding to obtain the designed transformer.

[0131] Among them, the primary winding refers to the primary side, that is, the voltage input side; the secondary winding refers to the secondary side, that is, the voltage output terminal. The number of turns of the primary winding is the number of turns of the coil required for the primary winding, and the number of turns of the secondary winding is the number of turns of the coil required for the secondary winding. After determining the number of turns, wind the stranded wire on the core according to the number of turns requirements to obtain the designed transformer.

[0132] In an alternative embodiment, in step 250, determining the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed may include:

[0133] Determine the input voltage of the primary winding and the output voltage of the secondary winding of the transformer to be designed;

[0134] According to the input voltage of the primary winding, use a fourth preliminary design formula for calculation to obtain the number of turns of the primary winding; wherein, the fourth preliminary design formula includes:

[0135]

[0136] Among them, N1 is the number of turns of the primary winding, K f is the form factor, B m is the working magnetic flux density, A e is the cross-sectional area of the magnetic core, f is the frequency, and V1 is the input voltage of the primary winding; and

[0137] According to the input voltage of the primary winding, the output voltage of the secondary winding, and the number of turns of the primary winding, a fifth preliminary calculation formula is used for calculation to obtain the number of turns of the secondary winding; among them, the fifth preliminary calculation formula includes:

[0138]

[0139] Among them, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, V1 is the input voltage of the primary winding, and V2 is the output voltage of the secondary winding.

[0140] In this embodiment, by setting the window depth of the magnetic core of the transformer to an integer multiple of the pitch of the stranded wire for winding the transformer winding, when winding the winding, the winding length of the stranded wire winding in the magnetic core will be an integer multiple of the pitch of the stranded wire, so as to suppress the proximity effect between the windings within the layer. Considering the influence between the windings within the layer and between different strands of multiple litz wires, it is possible to greatly reduce the proximity effect resistance, reduce the resistance loss, and improve the transformer efficiency.

[0141] Example 3

[0142] According to an embodiment of the present invention, there is also provided a transformer, which is manufactured by using the transformer magnetic core design method described in any one of the above embodiments.

[0143] The technical solution of the present invention has been described in detail above in conjunction with the accompanying drawings. Considering that in the related art, the existing technology of setting the primary winding and the secondary winding in a cross-over manner cannot reduce the proximity effect within the layer. The present invention provides a transformer magnetic core design method and a transformer. By setting the window depth of the magnetic core of the transformer to an integer multiple of the pitch of the stranded wire for winding the transformer winding, when winding the winding, the winding length of the stranded wire winding in the magnetic core will be an integer multiple of the pitch of the stranded wire, so as to suppress the proximity effect between the windings within the layer. Considering the influence between the windings within the layer and between different strands of multiple litz wires, it is possible to greatly reduce the proximity effect resistance, reduce the resistance loss, and improve the transformer efficiency.

[0144] Although the embodiments disclosed in the present invention are as above, the content described is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the protection scope of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for designing a transformer core, characterized in that, The method includes: Determining the pitch of the stranded wire for winding the transformer winding; Before determining the pitch of the stranded wire for winding the transformer winding, the method further includes: Determining the output power and output voltage of the transformer to be designed; According to the output power and output voltage of the transformer to be designed, determining the cross-sectional area of the stranded wire for winding the transformer winding; Selecting a stranded wire that meets the cross-sectional area from alternative stranded wires, and determining the pitch of the stranded wire for winding the transformer winding according to the specifications corresponding to the selected stranded wire; According to the core area of the transformer to be designed and the pitch, determining the core required for the transformer to be designed; wherein, the core area of the core is equal to the core area of the transformer to be designed, and the window depth of the core is an integer multiple of the pitch.

2. The transformer core design method according to claim 1, characterized in that, Before determining the core required for the transformer to be designed according to the core area of the transformer to be designed and the pitch, the method further includes: Determining the apparent power of the transformer to be designed; According to the apparent power, determining the core area of the transformer to be designed.

3. The transformer core design method according to claim 2, characterized in that, Determining the apparent power of the transformer to be designed includes: Determining the input power and output power of the transformer to be designed; According to the input power and the output power, determining the apparent power of the transformer to be designed.

4. The transformer core design method according to claim 3, characterized in that According to the input power and the output power, determining the apparent power of the transformer to be designed includes: According to the input power and the output power, using a first pre-designed formula to obtain the apparent power; wherein, the first pre-designed formula includes: P t = P1 + P2 Among them, P t is the apparent power, P1 is the input power, and P2 is the output power.

5. The method for designing a transformer core according to claim 2, wherein According to the apparent power, determining the core area of the transformer to be designed includes: According to the apparent power, performing a calculation using a second pre-designed formula to obtain the core area of the transformer to be designed; wherein, the second pre-designed formula includes: Among them, AP is the core area of the transformer to be designed, P t is the apparent power, K W is the window utilization factor, K f is the form factor, J is the current density, B m is the working magnetic flux density, f is the frequency.

6. The transformer core design method according to claim 1, wherein According to the output power and output voltage of the transformer to be designed, determining the cross-sectional area of the stranded wire for winding the transformer winding includes: According to the output power and output voltage of the transformer to be designed, performing a calculation using a third pre-designed formula to obtain the cross-sectional area of the stranded wire for winding the transformer winding; wherein, the third pre-designed formula includes: Wherein, A2 is the cross-sectional area of the stranded wire, P2 is the output power of the transformer to be designed, V2 is the output voltage of the transformer to be designed, and J is the current density.

7. The transformer core design method according to claim 1, characterized in that After determining the core required for the transformer to be designed according to the core area of the transformer to be designed and the pitch, the method further includes: Determining the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed, so as to wind the stranded wire on the core according to the number of turns of the primary winding and the number of turns of the secondary winding.

8. The method for designing a transformer core according to claim 6, wherein Determining the number of turns of the primary winding and the number of turns of the secondary winding required for the transformer to be designed includes: Determining the input voltage of the primary winding and the output voltage of the secondary winding of the transformer to be designed; According to the input voltage of the primary winding, performing a calculation using a fourth pre-designed formula to obtain the number of turns of the primary winding; wherein, the fourth pre-designed formula includes: where N1 is the number of turns of the primary winding, K f is the form factor, B m is the working magnetic flux density, A e is the cross-sectional area of the magnetic core, f is the frequency, and V1 is the input voltage of the primary winding; and According to the input voltage of the primary winding, the output voltage of the secondary winding, and the number of turns of the primary winding, calculate using the fifth pre-designed formula to obtain the number of turns of the secondary winding; wherein, the fifth pre-designed formula includes: Wherein, N1 is the number of turns of the primary winding, N2 is the number of turns of the secondary winding, V1 is the input voltage of the primary winding, and V2 is the output voltage of the secondary winding.

9. The transformer core design method according to claim 1, wherein The stranded wire is obtained by stranding at least two Litz wires.

10. A transformer, characterized in that, The transformer is manufactured by using the transformer core design method according to any one of claims 1 to 9.

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