CN201622921U - Transformer capable of reducing common-mode interference of flyback converter and flyback converter - Google Patents

Transformer capable of reducing common-mode interference of flyback converter and flyback converter Download PDF

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Publication number
CN201622921U
CN201622921U CN2010201393240U CN201020139324U CN201622921U CN 201622921 U CN201622921 U CN 201622921U CN 2010201393240 U CN2010201393240 U CN 2010201393240U CN 201020139324 U CN201020139324 U CN 201020139324U CN 201622921 U CN201622921 U CN 201622921U
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winding
input
transformer
magnetic core
output
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CN2010201393240U
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刘磊
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BCD Semiconductor Manufacturing Ltd
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BCD Semiconductor Manufacturing Ltd
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Abstract

The utility model discloses a transformer capable of reducing the common-mode interference of a flyback converter, which comprises a magnetic core, an input winding and an auxiliary winding coupled with the input winding. The transformer additionally comprises a shielding winding wound between the input winding and the magnetic core, and a balancing winding wound between the auxiliary winding and an output winding. The shielding winding, the input winding, the auxiliary winding, the balancing winding and the output winding are sequentially wound from the bottom layer to the outer layer of the magnetic core. The utility model additionally discloses the flyback converter. By adopting the embodiment of the utility model, the common-mode interference in the flyback converter can be effectively suppressed and good EMI effect can be obtained.

Description

A kind of transformer and inverse excitation type converter that reduces the inverse excitation type converter common mode disturbances
Technical field
The utility model relates to the transformer technology field, particularly relates to a kind of transformer and inverse excitation type converter that reduces the inverse excitation type converter common mode disturbances.
Background technology
Inverse excitation type converter is meant and uses the anti-converter that high frequency transformer is isolated the input and output loop that swashs that it adopts secondary control or former limit control mode usually.
With reference to Fig. 1, be typical inverse excitation type converter circuit structure diagram.Described converter 1 comprises: rectifier bridge 1a, input filter capacitor 2a, power switch 3a, control chip 4a, transformer 5a, rectifier diode 6a, output capacitance 7a.
Wherein, described transformer 5a has and stores and the function of transmission of power, the auxiliary winding 5a_3 that it comprises input winding 5a_1, output winding 5a_2, is coupled with input winding 5a_1; Described auxiliary winding 5a_3 is used to control chip 4a that energy is provided.Wherein, adopt stain to identify the end of the same name of each winding among Fig. 1.
The alternating voltage of input obtains the input voltage of transformer 5a through rectifier bridge 1a and input filter capacitor 2a; Alternating voltage on the described transformer 5a output winding 5a_2 obtains stable VD and output current by after the rectifier diode 6a rectification; Described power switch 3a, control chip 4a and transformer 5a constitute a feedback loop, the mean value of VD are controlled at the specified output valve of needs.
With reference to Fig. 2, be transformer cross-sectional view shown in Figure 1.Described transformer 5a also comprises the magnetic core 5a_4 of high magnetic flux density.Described Transformer Winding is followed successively by to skin from the bottom of described magnetic core 5a_4: input winding 5a_1, auxiliary winding 5a_3, output winding 5a_2; Wherein, described input winding 5a_1 generally comprises 3 layers; Has insulating tape between described input winding 5a_1 and the auxiliary winding 5a_3.
Simultaneously, as shown in Figure 2, between each layer of transformer 5a winding, be equipped with parasitic capacitance; Be provided with between described input winding 5a_1 and magnetic core 5a_4 between input and magnetic core parasitic capacitance 5a_5, the input winding 5a_1 adjacent two layers and be provided with parasitic capacitance 5a_6 between input layer; Be provided with input and auxiliary parasitic capacitance 5a_7 between described input winding 5a_1 and the auxiliary winding 5a_3; Be provided with auxiliary between described auxiliary winding 5a_3 and the output winding 5a_2 and output parasitic capacitance 5a_8; Be provided with output and magnetic core parasitic capacitance 5a_9 between described output winding 5a_2 and the magnetic core 5a_4.
In the converter 1 shown in Figure 1, described power switch 3a open or shutoff can cause the saltus step of voltage on it, in converter, can produce common mode current, electrical network is produced disturbs; Flow in the parasitic capacitance that described common mode current can exist between each winding of transformer 5a.
In the prior art, in order to reduce the common mode disturbances in the converter, the measure of often taking is to increase Y electric capacity 2 between the ground of the high-pressure side of the input winding 5a_1 of transformer 5a and output winding 5a_2, as shown in accompanying drawing 1.Described Y electric capacity 2 provides low-impedance path for the common mode current between the input winding 5a_1 of transformer 5a and the output winding 5a_2, make common mode current can turn back to its generation source without ground, thereby reduced the common mode disturbances of system by Y electric capacity 2.
The inventor is by to the discovering of prior art, described Y electric capacity 2 can make between the secondary output voltage of isolating originally and the former limit input voltage and have leakage current, and when Y electric capacity 2 was big more, described leakage current was big more.
The utility model content
In view of this, the purpose of this utility model is to provide a kind of transformer and inverse excitation type converter that reduces the inverse excitation type converter common mode disturbances, can effectively reduce the common mode disturbances of converter.
The utility model provides a kind of transformer that reduces the inverse excitation type converter common mode disturbances, comprise magnetic core, input winding, with the auxiliary winding that is coupled of input winding, described transformer also comprises: be wound on the shielding winding between described input winding and the magnetic core and be wound on described auxiliary winding and the balance winding of exporting between the winding; Wherein, from the bottom of described magnetic core to skin coiling successively: shielding winding, input winding, auxiliary winding, balance winding, output winding.
Preferably, described auxiliary winding is by enamelled wire 1 layer of coiling side by side, and the coiling direction is identical with the input winding.
Preferably, described auxiliary winding is by enamelled wire 2 layers of coilings side by side, and the coiling direction is identical with the input winding.
Preferably, described shielding winding is by 1 layer of sub-thread enamelled wire coiling, and the coiling direction is identical with the input winding.
Preferably, the number of turn of described shielding winding is 40% to 90% of the described input winding individual layer number of turn.
Preferably, the even coiling of described balance winding, and the number of turn is 40% to 90% of a described output umber of turn.
The utility model also provides a kind of inverse excitation type converter, and described inverse excitation type converter comprises described transformer.
According to the specific embodiment that the utility model provides, the utility model discloses following technique effect:
The utility model is implemented the transformer of described reduction inverse excitation type converter common mode disturbances, increase the shielding winding between the input winding of transformer and the magnetic core, at increase balance winding between described auxiliary winding and the output winding, because the induced voltage that produces on described shielding winding and the balance winding makes that the equivalent common mode capacitance between input winding and the output winding reduces.According to formula As can be known, under the certain situation of voltage change ratio, reduce equivalent common mode capacitance and can effectively reduce the common mode current of exporting between winding and the input winding, thereby reduce the common mode disturbances of converter, obtain good EMI result.
Description of drawings
Fig. 1 is typical inverse excitation type converter circuit structure diagram;
Fig. 2 is a transformer cross-sectional view shown in Figure 1;
Fig. 3 is typical inverse excitation type converter common mode current transmission path schematic diagram;
Fig. 4 a is the transformer cross-sectional view of the utility model embodiment one described reduction inverse excitation type converter common mode disturbances;
Fig. 4 b is the transformer principle figure of the utility model embodiment one described reduction inverse excitation type converter common mode disturbances;
Fig. 5 is the transformer cross-sectional view of the utility model embodiment two described reduction inverse excitation type converter common mode disturbances.
Embodiment
The purpose of this utility model is to provide a kind of transformer and inverse excitation type converter that reduces the inverse excitation type converter common mode disturbances, can effectively reduce the common mode disturbances of converter,, obtain good electromagnetic interference (EMI:Electro Magnetic Interference) result.
For above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, the utility model is described in further detail below in conjunction with the drawings and specific embodiments.
With reference to Fig. 3, be typical inverse excitation type converter common mode current transmission path schematic diagram.Described inverse excitation type converter U1 comprises: rectifier bridge U11, input filter capacitor U12, power switch U13, control chip U14, transformer U15, rectifier diode U16, output capacitance U17.
For inverse excitation type converter, the conducted interference of its EMI adopts linear impedance stabilization network (LISN:Line Impedance Stabilization Network) to carry out conduction test.The interference source that produced by examination equipment (EUT:Equipment Under Test) passes through the high pass filter of LISN inside and the resistance of 50 Ω, converts disturbance current to the correspondent voltage value, is analyzed by receiver.Conducted interference is divided into differential mode interference and common mode disturbances, common mode disturbances generally be since in the switching process transient changing of voltage produce, the transient changing of voltage can be by parasitic capacitance equidirectional flowing on two input power cords, and constitute current circuit with the earth respectively, promptly the while is as the source line and the loop line of common mode current.
As shown in Figure 3, in inverse excitation type converter, its common mode disturbances source comprises the power switch U13 that is arranged on the former limit of transformer U15 and the rectifier diode U16 of secondary.
The common mode current that described power switch U13 produces to the equivalent common mode capacitance U151 of secondary and the secondary output line electric capacity U153 between over the ground, constitutes first loop with LISN U2 by the former limit of transformer U15; The common mode current that described rectifier diode U16 produces to the equivalent common mode capacitance U152 on former limit and the secondary output line electric capacity U153 between over the ground, constitutes second loop with LISN U2 by secondary.Two paths of signals on LISN U2 and be the signal that the receiver (not shown) is received.If the amplitude of two-way common mode current is more little, and on both direction balance mutually, the signal that then produces on receiver is more little, the EMI effect is good more, converter is more little to the interference of electrical network.
With reference to Fig. 4 a and Fig. 4 b, be respectively the utility model embodiment one described reduction inverse excitation type converter common mode disturbances transformer cross-sectional view and schematic diagram.
Shown in Fig. 4 a, described transformer comprises: magnetic core 10, input winding 20, auxiliary winding 30, output winding 40; Wherein, described auxiliary winding 30 is coupled with input winding 20; 3 layers of described input winding 20 coilings; Be provided with insulating tape between described input winding 20 and the auxiliary winding 30.
Between described input winding 20 and magnetic core 10, increase shielding winding 50; Between described auxiliary winding 30 and output winding 40, increase balance winding 60;
The winding of described transformer twines to skin from bottom successively around described magnetic core 10; Wherein, be respectively to skin from described magnetic core 10 bottoms: 60,1 layer of output of 1 layer of 20,1 layer of auxiliary winding 30,1 layer equilibration winding of shielding winding 50,3 layers of input winding winding 40.Wherein,
Concrete, the winding that can set described transformer is respectively the 1st layer, the 2nd layer from described magnetic core 10 bottoms to skin ..., n layer (n is total number of plies that described transformer has winding).
Shown in Fig. 4 a, the winding of the utility model embodiment one described transformer comprises 7 layers (being n=7) altogether, and then the bottom from described magnetic core 10 is followed successively by to skin: the 1st layer is output winding 40 for auxiliary winding 30, the 6th layer for balance winding 60, the 7th layer for input winding 20, the 5th layer for shielding winding 50, layer 2-4.
Described shielding winding 50 is between described input winding 20 and magnetic core 10, and by 1 layer of sub-thread enamelled wire coiling, and its coiling direction is identical with input winding 20.
Because described shielding winding 50 is arranged between described input winding 20 and the magnetic core 10, make the distance between input winding 20 and the magnetic core 10 become big, electric field between input winding 20 and the magnetic core 10 dies down, charge inducing reduces, parasitic capacitance diminishes, thereby can reduce the common mode current between input winding 20 and the magnetic core 10.
The number of turn of described shielding winding 50 is relevant with the number of turn of described input winding 20.According to practical application experience as can be known, in order to reach good shield effectiveness, should make corresponding the lacking of the number of turn of the turn ratio input winding 20 of described shielding winding 50; Generally, the number of turn that can set described shielding winding 50 for the input winding 20 individual layer numbers of turn half or half about, its concrete value can be set and adjust in conjunction with the number of turn of described input winding 20 according to actual needs.
Preferably, the number of turn of described shielding winding 50 be described input winding 20 the number of turn 40% to 90%.
Described balance winding 60 is between described auxiliary winding 30 and output winding 40, make auxiliary winding 30 and parasitic capacitance between the output winding 40 become parasitic capacitance and the balance winding 60 between auxiliary winding 30 and the balance winding 60 and export that parasitic capacitance is in series between the winding 40, simultaneously the induced voltage that produces on the balance winding 60 make between auxiliary winding 30 and the balance winding 60 and balance winding 60 and output winding 40 between pressure reduction reduce, thereby reduced output winding 40 greatly to the equivalent common mode capacitance between the auxiliary winding 30, effectively reduced output winding 40 common mode currents to auxiliary winding 30.
The number of turn of described balance winding 60 is relevant with the number of turn of described output winding 40.According to practical application experience as can be known, generally can set the equal turn numbers of the number of turn of described balance winding 60 and described output winding 40 or close, its concrete value can be set and adjust in conjunction with the number of turn of described output winding 40 according to actual needs.
Preferably, the number of turn of described balance winding 60 is that described output is around 40% to 90% of 40 numbers of turn.
Need to prove that described input winding 20 divides 3 layers of coiling by the sub-thread enamelled wire, thus, make the pressure drop of every layer of input winding 20 only be 1/3 of total input winding pressure drop.
The end of the same name of described shielding winding 50 and balance winding 40 is associated in together, and links to each other the zero potential of promptly former limit circuit with the different name end of auxiliary winding 30.
The transformer of the utility model embodiment one described reduction inverse excitation type converter common mode disturbances, increase shielding winding 50 between the input winding 20 of transformer and the magnetic core 10, at increase balance winding 60 between described auxiliary winding 30 and the output winding 40, because the induced voltage that produces on described shielding winding 50 and the balance winding 60 makes that the equivalent common mode capacitance between input winding 20 and the output winding 40 has reduced.Wherein, described auxiliary winding 30 has reduced the parasitic capacitance between input winding 20 and the magnetic core 10, and balance winding 60 has reduced the parasitic capacitance between auxiliary winding 30 and the output winding 40,
According to by formula known in this field As can be known, under the certain situation of voltage change ratio, reduce equivalent common mode capacitance and can effectively reduce the common mode current of exporting between winding 40 and the input winding 20, thereby reduce the common mode disturbances of converter, obtain good EMI result.
With reference to Fig. 5 is the utility model embodiment two described transformer cross-sectional views.The difference of the utility model embodiment two described transformers and embodiment one is: 2 layers of described auxiliary winding 30 coilings.
Concrete, the winding of the utility model embodiment two described transformers is respectively to skin from described magnetic core 10 bottoms: 60,1 layer of output of 1 layer of 20,2 layers of auxiliary winding 30,1 layer equilibration winding of shielding winding 50,3 layers of input winding winding 40.
Concrete, as shown in Figure 5, the winding of the utility model embodiment two described transformers comprises 8 layers (being n=8) altogether, and then the bottom from described magnetic core 10 is followed successively by to skin: the 1st layer is output winding 40 for auxiliary winding 30, the 7th layer for balance winding 60, the 8th layer for input winding 20,5-6 layer for shielding winding 50, layer 2-4.
Need to prove, among the embodiment two, described auxiliary winding 30 is by enamelled wire 2 layers of coilings side by side, make the distance between input winding 20 and the output winding 40 further become big, therefore parasitic capacitance therebetween diminishes, at this moment, the corresponding minimizing of the number of turn of balance winding 60 is to reach the effect of the common mode current on reduction and balance two transmission paths.
Simultaneously, the thickness of the enamelled wire of described balance winding 60 affects described input winding 20 equally and exports the distance and the parasitic capacitance of 30 of windings, therefore, the line footpath of suitably regulating the enamelled wire of described balance winding 60 also can reach and reduce the common mode current effects of jamming.
The utility model embodiment provides a kind of transformer that reduces the inverse excitation type converter common mode disturbances, can effectively reduce the common mode disturbances of converter, obtains good EMI result.Simultaneously, the utility model also provides a kind of inverse excitation type converter, and described inverse excitation type converter comprises the described transformer as above-mentioned embodiment, makes that thus the common mode disturbances of this inverse excitation type converter is lower, has good EMI result.
Preferably, transformer described in the utility model, be applicable to the inverse excitation type converter of any pattern, comprise the control of former limit with secondary control, and when transformer described in the utility model is used for inverse excitation type converter, its circuit connecting mode is identical with the connected mode of existing described transformer, repeats no more.
More than to a kind of transformer and inverse excitation type converter that reduces the inverse excitation type converter common mode disturbances provided by the utility model, be described in detail, used specific case herein principle of the present utility model and execution mode are set forth, the explanation of above embodiment just is used for helping to understand method of the present utility model and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present utility model, part in specific embodiments and applications all can change.In sum, this description should not be construed as restriction of the present utility model.

Claims (7)

1. transformer that reduces the inverse excitation type converter common mode disturbances, comprise magnetic core, input winding, with the auxiliary winding that is coupled of input winding, it is characterized in that described transformer also comprises: be wound on the shielding winding between described input winding and the magnetic core and be wound on described auxiliary winding and the balance winding of output between the winding; Wherein, the bottom from described magnetic core is wound with successively to skin: shielding winding, input winding, auxiliary winding, balance winding, output winding.
2. transformer according to claim 1 is characterized in that, described auxiliary winding is by enamelled wire 1 layer of coiling side by side, and the coiling direction is identical with the input winding.
3. transformer according to claim 1 is characterized in that, described auxiliary winding is by enamelled wire 2 layers of coilings side by side, and the coiling direction is identical with the input winding.
4. transformer according to claim 1 is characterized in that, described shielding winding is by 1 layer of sub-thread enamelled wire coiling, and the coiling direction is identical with the input winding.
5. transformer according to claim 1 is characterized in that, the number of turn of described shielding winding is 40% to 90% of the described input winding individual layer number of turn.
6. transformer according to claim 1 is characterized in that, the even coiling of described balance winding, and the number of turn is 40% to 90% of a described output umber of turn.
7. an inverse excitation type converter is characterized in that, described inverse excitation type converter comprises each described transformer as claim 1-5.
CN2010201393240U 2010-03-19 2010-03-19 Transformer capable of reducing common-mode interference of flyback converter and flyback converter Expired - Lifetime CN201622921U (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103093936A (en) * 2011-11-02 2013-05-08 施耐德电器工业公司 Transformer and winding method thereof
CN103310956A (en) * 2012-03-06 2013-09-18 台达电子企业管理(上海)有限公司 Transformer capable of inhibiting common-mode current and power converter thereof
CN106385185A (en) * 2016-09-27 2017-02-08 青岛海信电器股份有限公司 Flyback switching power source and method for improving electromagnetic compatibility of flyback switching power source
CN109639128A (en) * 2018-12-10 2019-04-16 广东工业大学 Method of the optimization transformer device structure to reduce inverse-excitation type switch power-supply conduction common mode interference
WO2019091393A1 (en) * 2017-11-10 2019-05-16 华为技术有限公司 Planar transformer, power source switching circuit and adapter
CN110211799A (en) * 2019-06-06 2019-09-06 浙江大学 Flyback sourse Transformer shielding umber of turn design method
CN111312489A (en) * 2020-02-20 2020-06-19 连云港杰瑞电子有限公司 Transformer winding arrangement method and displacement current numerical analysis method thereof

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103093936B (en) * 2011-11-02 2016-06-08 施耐德电器工业公司 Transformer and winding method thereof
CN103093936A (en) * 2011-11-02 2013-05-08 施耐德电器工业公司 Transformer and winding method thereof
CN103310956A (en) * 2012-03-06 2013-09-18 台达电子企业管理(上海)有限公司 Transformer capable of inhibiting common-mode current and power converter thereof
US9129736B2 (en) 2012-03-06 2015-09-08 Delta Electronics (Shanghai) Co., Ltd. Transformer capable of suppressing common mode current and power converter thereof
CN103310956B (en) * 2012-03-06 2016-03-23 台达电子企业管理(上海)有限公司 A kind of transformer and power inverter thereof suppressing common mode current
CN106385185A (en) * 2016-09-27 2017-02-08 青岛海信电器股份有限公司 Flyback switching power source and method for improving electromagnetic compatibility of flyback switching power source
US11062837B2 (en) 2017-11-10 2021-07-13 Huawei Technologies Co., Ltd. Planar transformer, power conversion circuit, and adapter
WO2019091393A1 (en) * 2017-11-10 2019-05-16 华为技术有限公司 Planar transformer, power source switching circuit and adapter
CN109639128A (en) * 2018-12-10 2019-04-16 广东工业大学 Method of the optimization transformer device structure to reduce inverse-excitation type switch power-supply conduction common mode interference
CN110211799B (en) * 2019-06-06 2020-04-14 浙江大学 Method for designing turns of shielding winding of flyback power transformer
CN110211799A (en) * 2019-06-06 2019-09-06 浙江大学 Flyback sourse Transformer shielding umber of turn design method
CN111312489A (en) * 2020-02-20 2020-06-19 连云港杰瑞电子有限公司 Transformer winding arrangement method and displacement current numerical analysis method thereof
CN111312489B (en) * 2020-02-20 2021-08-17 连云港杰瑞电子有限公司 Transformer winding arrangement method and displacement current numerical analysis method thereof

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