WO2020248672A1 - 平面变压器、电源转换电路以及适配器 - Google Patents

平面变压器、电源转换电路以及适配器 Download PDF

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Publication number
WO2020248672A1
WO2020248672A1 PCT/CN2020/083477 CN2020083477W WO2020248672A1 WO 2020248672 A1 WO2020248672 A1 WO 2020248672A1 CN 2020083477 W CN2020083477 W CN 2020083477W WO 2020248672 A1 WO2020248672 A1 WO 2020248672A1
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Prior art keywords
winding
primary
circuit
compensation
planar transformer
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PCT/CN2020/083477
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English (en)
French (fr)
Inventor
余鹏
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华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20822966.6A priority Critical patent/EP3979277A4/en
Publication of WO2020248672A1 publication Critical patent/WO2020248672A1/zh
Priority to US17/550,188 priority patent/US20220102057A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/288—Shielding
    • H01F27/289—Shielding with auxiliary windings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/29—Terminals; Tapping arrangements for signal inductances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/38—Auxiliary core members; Auxiliary coils or windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H01F2027/2809—Printed windings on stacked layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2804—Printed windings
    • H01F2027/2819—Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/16—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
    • H05K1/165—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed inductors
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/08—Magnetic details
    • H05K2201/083—Magnetic materials
    • H05K2201/086—Magnetic materials for inductive purposes, e.g. printed inductor with ferrite core

Definitions

  • This application relates to the field of circuits, and more specifically, to a planar transformer, a voltage conversion circuit, and an adapter.
  • Switching power supplies have developed rapidly due to their high efficiency, small size and good output stability.
  • the problem of the switching power supply suffering from noise interference in the working process is very prominent.
  • the noise suffered by the switching power supply includes the noise from the outside, the noise generated by the turn-off and conduction of its own switching device, the noise generated by the reverse recovery of the rectifier diode, and the noise generated by the capacitor/inductance/wire in its own circuit.
  • the electrical circuit network conducts and radiates to electrical equipment, and will cause the electrical equipment to suffer from electromagnetic interference (EMI). Therefore, the requirement of switching power supply for noise suppression is very strict.
  • the noise suffered by the switching power supply includes common mode noise.
  • Common mode noise mainly includes the noise to the reference ground caused by the interaction of various parameters of the switching power supply circuit. How to reduce or even eliminate the common mode noise of the switching power supply is of great concern to the industry problem.
  • the present application provides a planar transformer, a power conversion circuit, and an adapter, which can improve the performance of noise suppression.
  • a planar transformer including a magnetic core and a printed circuit board PCB winding board, wherein the PCB winding board includes:
  • a primary winding the first end of the primary winding is connected to the potential static point of the primary circuit of the power conversion circuit, wherein the first end of the primary winding is the first turn of the primary winding;
  • a secondary winding the first end of the secondary winding is connected to the potential static point of the secondary circuit of the power conversion circuit, wherein the first end of the secondary winding is 1st turn coil;
  • a shielding winding arranged between the primary winding and the secondary winding, for shielding the electric field coupling between the primary winding and the secondary winding;
  • the compensation winding is adjacent to the primary winding or adjacent to the secondary winding.
  • the compensation winding includes N turns of coils, and N is a positive number greater than 1.
  • the shield winding can shield the electric field coupling between the primary winding and the secondary winding, thereby suppressing
  • the common mode noise generated by the compensation winding will be offset with the common mode noise flowing to the secondary winding or the primary winding, thereby achieving the lowest common mode noise of the entire system.
  • the shield winding can reduce the noise current between the primary winding and the secondary winding, the total number of turns of the compensation winding can be reduced, based on the number of turns of the compensation winding required by the embodiment of the application Lowering helps the design and mass production consistency of PCB winding boards.
  • the embodiments of the present application can sufficiently suppress common mode noise, the embodiments of the present application can effectively reduce the conducted emission CE, and thus can reduce the input common mode inductance.
  • the embodiment of the present application adopts electromagnetic shielding technology, which can reduce the frequency coupling effect of the secondary winding on the primary winding, thereby reducing the radiated emission RE.
  • the power conversion circuit in the embodiments of the present application can reduce or even eliminate the Y capacitors connected to the primary circuit and the secondary circuit. Therefore, a safer power conversion circuit with small Y capacitors or even no Y capacitors can be provided, and the cost and volume of the power conversion circuit can be reduced.
  • the shield winding can shield the electric field coupling between the primary winding and the secondary winding, including the following two situations.
  • the shield winding when the first end of the shield winding is connected to the static potential of the primary circuit, the shield winding can shield the electric field of the primary winding from coupling to the secondary winding. At this time, the shield winding can be arranged close to the secondary winding, that is, adjacent to the secondary winding.
  • the shield winding when the first end of the shield winding is connected to the potential static point of the secondary circuit, the shield winding can shield the electric field of the secondary winding from coupling to the primary winding. At this time, the shield winding can be arranged close to the primary winding, that is, adjacent to the primary winding.
  • the shield winding is used to shield the electric field of the primary winding from coupling to the secondary winding, which means that the shield winding can shield the noise current coupled from the primary winding to the secondary winding.
  • the shield winding may shield the noise current directly coupled to the secondary winding by the primary winding, or shield the noise current coupled to the secondary winding through the turn-to-turn gap of the compensation winding, which is not limited in the embodiment of the present application.
  • the shield winding is adjacent to the primary winding.
  • the shield winding may be adjacent to the primary winding at this time, or the shield winding may be adjacent to both the primary winding and the secondary winding.
  • the first end of the compensation winding is connected to the static potential of the primary circuit, and the second end can be suspended.
  • the shield winding may be adjacent to the secondary winding.
  • the shield winding may be adjacent to the secondary winding at this time, or the shield winding may be adjacent to both the primary winding and the secondary winding.
  • the first end of the compensation winding is connected to the potential static point of the secondary circuit, and the second end can be suspended.
  • the shield winding when the shield winding is adjacent to the primary winding and the secondary winding, the shield winding can shield the noise current directly coupled to the secondary winding from the primary winding. When the shield winding is adjacent to the compensation winding, the shield winding can shield the noise current of the primary winding coupled to the secondary winding through the inter-turn gap of the compensation winding.
  • the shielding winding can be arranged between the primary winding and the secondary winding respectively. Shield the electric field coupling of the primary winding to the secondary winding. Further, in the embodiment of the present application, the number of shielding windings may be one, two, or more, which is not limited in the embodiment of the present application.
  • the number of compensation windings may be at least one (for example, one, two or more), which is not limited in the embodiment of the present application.
  • the projection of the primary winding on the first plane along the z-axis and/or the secondary winding on the first plane along the z-axis The projection of the shield winding is located in the projection of the shield winding on the first plane along the z-axis, the first plane is the plane where the surface of the PCB winding plate is located, and the z-axis is perpendicular to the first flat.
  • the projection of the PCB winding plate on the first plane is a ring shape
  • the cross section is perpendicular to the first plane
  • the primary winding, the secondary winding and the shielding winding are all located in the cross section .
  • the shield winding can better shield the electric field coupling between the primary winding and the secondary winding.
  • the compensation winding is adjacent to the secondary winding, and the first end of the compensation winding is connected to the static potential of the primary circuit.
  • the compensation winding is adjacent to the primary winding, and the first end of the compensation winding is connected to the potential static point of the secondary circuit.
  • the secondary circuit includes a secondary rectifier tube and a secondary filter capacitor, and when the secondary rectifier tube is connected to the negative electrode of the secondary filter capacitor , The first end of the compensation winding and the first end of the primary winding are opposite ends of each other.
  • the secondary circuit includes a secondary rectifier tube and a secondary filter capacitor, and when the secondary rectifier tube is connected to the anode of the secondary filter capacitor , The first end of the compensation winding and the first end of the primary winding are mutually homonymous ends.
  • the compensation winding is adjacent to the first winding layer in the first winding, wherein the first winding is a primary adjacent to the compensation winding A winding, or a secondary winding adjacent to the compensation winding, the first winding layer is provided with the Ns-th to Ns+B-1th-turn coils of the first winding, where N satisfies the following conditions:
  • the induced voltage generated by the Nb-turn coil is equal to the induced voltage generated by the first winding
  • C is a real number greater than 0
  • Nb, Ns, and B are positive numbers.
  • the number of turns of the winding is restricted to a certain extent due to the space limitation of the winding channel of the PCB. Therefore, the coil with the smaller number of turns in the secondary winding can be preferentially arranged adjacent to the compensation winding, which can further reduce the value of Nb.
  • the value range of C is [1.56, 2.16] or (0, 1].
  • the secondary circuit includes a secondary rectifier tube and a secondary filter capacitor.
  • the secondary rectifier tube When the secondary rectifier tube is connected to the negative electrode of the secondary filter capacitor, the first end of the compensation winding and the In the case where the first ends of the primary windings have different names, the value of C is greater than 1.
  • the noise current that the compensation winding needs to cancel is greater than the common mode noise generated by the secondary winding.
  • the number of turns Nb of the coil can be positively compensated by setting the value of C (greater than 1) to further obtain compensation
  • the number of turns of the winding 54 is N. Since the shield winding can reduce or even eliminate the noise current Isp flowing to the ground from the jump voltage Vp in the primary circuit coupled to the secondary winding, the value of C can be reduced by setting the shield winding, that is, the turns of the compensation winding can be reduced. number. In some optional embodiments, the value range of C is [1.56, 2.16].
  • the secondary circuit includes a secondary rectifier tube and a secondary filter capacitor.
  • the secondary rectifier tube When the secondary rectifier tube is connected to the anode of the secondary filter capacitor, the first end of the compensation winding and the In the case where the first ends of the primary windings are mutually identical ends, the value range of C is (0, 1).
  • the noise current that the compensation winding needs to cancel is smaller than the common mode noise generated by the secondary winding.
  • N of the compensation winding 54 Since the shield winding can reduce or even eliminate the noise current Id1 flowing to the ground from the jump voltage Vp in the primary circuit coupled to the secondary winding, the value of C can be reduced by setting the shield winding, that is, the turn of the compensation winding can be reduced. number.
  • the value of C may be determined according to the noise current coupled to the line impedance stabilization network LISN by the potential jump of the primary winding through the spatial coupling capacitor.
  • the second end of the compensation winding is suspended.
  • the potential static point of the primary circuit includes a point in the primary circuit connected to the positive pole of the bus capacitor or the primary working ground network, and the potential static point of the secondary circuit The point includes the point in the secondary circuit connected to the positive pole of the secondary output filter capacitor or the secondary working ground network, wherein the potential static point has no voltage jump during the circuit operation.
  • the primary winding includes at least one turn of the primary power winding, and/or an auxiliary winding connected to the primary circuit.
  • the secondary winding includes at least one turn of a secondary power winding, and/or an auxiliary winding connected to the primary circuit.
  • the first end of the shield winding is connected to the potential static point of the primary circuit or the potential static point of the secondary winding, and the shield winding The second end is suspended.
  • a power conversion circuit including: a planar transformer, a primary circuit, and a secondary circuit as in the first aspect and any possible implementation of the first aspect, the planar transformer is arranged on the primary Between the circuit and the secondary circuit.
  • an adapter including the power conversion circuit described in the second aspect.
  • Fig. 1 is a schematic diagram of an application scenario of an embodiment of the present application.
  • Fig. 2 is a schematic diagram of a power conversion circuit according to an embodiment of the present application.
  • Fig. 3 is a schematic diagram of a power conversion circuit according to an embodiment of the present application.
  • Fig. 4 is a schematic diagram of a planar transformer according to an embodiment of the present application.
  • Fig. 5 is a schematic cross-sectional view of a planar transformer according to an embodiment of the present application.
  • Fig. 6 is a schematic cross-sectional view of another planar transformer according to an embodiment of the present application.
  • Fig. 7 is a schematic cross-sectional view of another planar transformer according to an embodiment of the present application.
  • Fig. 8 is a schematic cross-sectional view of another planar transformer according to an embodiment of the present application.
  • Fig. 9 is a schematic cross-sectional view of another planar transformer according to an embodiment of the present application.
  • Fig. 10 is a schematic cross-sectional view of another planar transformer according to an embodiment of the present application.
  • Fig. 11 is a schematic cross-sectional view of another planar transformer according to an embodiment of the present application.
  • Fig. 12 is an example of the secondary winding and the compensation winding in the embodiment of the present application.
  • FIG. 13 is another example of the secondary winding and the compensation winding in the embodiment of the present application.
  • Figure 14 is a schematic diagram of the common mode noise path in the power conversion circuit.
  • Figure 15 is a schematic diagram of a common mode noise path in a planar transformer.
  • Figure 16 is a schematic diagram of the common mode noise path in the power conversion circuit.
  • Planar transformer Different from the traditional transformer structure, the magnetic core and winding of the planar transformer are planar structures.
  • the magnetic core generally adopts a flat magnetic core structure, such as a small-sized E-type magnetic core structure or an RM-type magnetic core structure.
  • Windings are generally made of multilayer printed circuit boards (printed circuit boards, PCB). This design has lower DC resistance, smaller leakage inductance and distributed capacitance, and has a small height and can have a higher operating frequency. .
  • Flyback converter It is widely used in AC/DC and DC/DC conversion. It is a relatively common low-power switching power supply converter with the advantages of simple structure and low cost. Its core components include power switch tubes, transformers, diodes and capacitors. The power switch tube is controlled by pulse width modulation, which generates a high-frequency square wave signal in the primary coil of the transformer by closing and conducting, and then is inductively coupled to the secondary coil of the transformer to realize energy transfer. Through the filtering and rectification of the diode and capacitor of the secondary circuit, a stable DC output is obtained at the output end.
  • Common mode noise is also called asymmetric noise or line-to-ground noise. This kind of noise exists in electrical equipment that uses AC power. The current of common mode noise flows in the same direction on two transmission lines. The phase to ground remains the same and returns through the ground wire. Common mode noise can be suppressed by using a Y capacitor in the common mode inductor or between the two power lines and ground.
  • Potential static point In the circuit network, the voltage potential amplitude on the network node remains relatively constant during the circuit operation, and there is no high-frequency jump or oscillation.
  • the filter capacitor after the rectification of the primary side circuit of the flyback converter and the filter capacitor after the rectification of the secondary side circuit, the positive or negative of these capacitors and the network node directly connected to it are the potential static points.
  • This application provides a planar transformer, a power conversion circuit and an adapter.
  • the above-mentioned transformer may be installed in a power conversion circuit
  • the above-mentioned power conversion circuit may be installed in an adapter.
  • the adapter can be applied to scenarios where devices are charged or powered.
  • Fig. 1 shows a possible application scenario of an embodiment of the present application.
  • the application scenario includes an external power supply 11, an adapter 12, and a device 13 to be charged.
  • the aforementioned device to be charged 13 may include a cellular phone, a notebook computer, a battery, etc., which is not limited in the embodiment of the present application.
  • the adapter 12 can be connected to the external power supply 11.
  • the power conversion circuit included in the adapter 12 is used to convert the higher voltage provided by the external power supply 11 into a lower voltage that meets the charging or power supply standard of the device 13 to be charged, and provides The charging device 13 performs charging or power supply.
  • the planar transformer provided in the embodiment of the present application can reduce noise generated during operation.
  • the aforementioned noise may include common mode noise.
  • the aforementioned power conversion circuit may be a switching power converter.
  • the switching power converter may include a flyback converter.
  • the common mode noise is mainly caused by the interaction between the various parameters of the switching power supply circuit and the noise to the reference ground. The mechanism of the common mode noise generation and transmission in the power conversion circuit 20 will be introduced below in conjunction with FIG. 2 and FIG. 3.
  • the power conversion circuit 20 generally includes a primary circuit 21, a secondary circuit 22 and a transformer 23.
  • the primary circuit usually includes a primary switch tube 211 and a primary filter capacitor 212. Further, the primary circuit also includes a rectifier circuit.
  • the aforementioned primary switch tube 211 may also be referred to as a power switch tube.
  • the secondary circuit 22 generally includes a secondary rectifier tube 221 and a secondary filter capacitor 222.
  • the transformer 23 includes a primary winding 231, a magnetic core, and a secondary winding 232.
  • the primary winding 231 can be connected to the primary switching tube 211 and the primary filter capacitor 212, and the secondary winding 232 can be connected to the secondary rectifier tube 221 and the secondary filter capacitor 222.
  • the primary filter capacitor 212 and the secondary filter capacitor 222 are usually electrolytic capacitors.
  • the node connected to any one of the two ends of the primary filter capacitor 212 is the potential static point of the primary circuit, or the ground node of the primary circuit can also be the potential static point of the primary circuit.
  • the node connected to any one of the two ends of the secondary filter capacitor 222 is the potential static point of the secondary circuit.
  • the AC power input from the external power source 11 is rectified and filtered by the primary circuit 21 and then converted into a stable high-voltage DC power and input to the primary winding 231 of the transformer 23.
  • the primary switch tube 211 connected to the primary winding 231 is turned on and off at high frequency to couple the voltage on the primary winding 231 to the secondary winding 232.
  • low-voltage direct current is output to the load to charge or power the load.
  • the aforementioned load is the aforementioned device to be charged 13.
  • the primary switching tube 211 generates a jump voltage Vp due to the high-frequency turn-on and turn-off
  • the secondary rectifier tube 221 generates a jump voltage Vp due to the high-frequency turn-on and turn-off. Vs.
  • the jump voltages Vp and Vs Due to the parasitic capacitance between the primary winding 231 and the secondary winding 232 of the transformer, the jump voltages Vp and Vs generate common mode noise in the power conversion circuit through the parasitic capacitance.
  • the above-mentioned parasitic capacitance includes the distributed capacitance Cps between the primary winding and the secondary winding and the distributed capacitance Csp between the secondary winding and the primary winding.
  • the jump voltage Vp in the primary circuit generates a noise current Ips flowing to the ground through Cps
  • the jump voltage Vs in the secondary circuit generates a noise current Isp flowing to the ground through Csp.
  • the above-mentioned noise current Ips and noise current Isp are common mode noise.
  • Figure 3 also shows the Line Impedance Stabilization Network (LISN) circuit.
  • the LISN circuit is a test circuit used to detect the common mode noise current flowing into the ground when the power conversion circuit is working. In other words, it can be considered that the ground current detected by the LISN network is equivalent to the common mode noise generated by the power conversion circuit.
  • the embodiments of the present application propose a planar transformer with lower common mode noise.
  • the power conversion circuit using the planar transformer has higher noise suppression performance, and the conducted emission of the power conversion circuit CE) and radiation emission (radiation emission, RE) can be reduced.
  • the application also provides a power conversion circuit using the planar transformer and an adapter using the power conversion circuit.
  • the planar transformer, the power conversion circuit, and the adapter can be referred to the description in FIG. 1 to FIG. 3, and for the sake of brevity, details are not repeated here.
  • the transformer provided in the embodiments of the present application mainly consists of a magnetic core and winding coils.
  • the winding coil can be a traditional copper wire firing, or it can be formed by etching a multilayer PCB.
  • the latter is generally called a planar transformer because it is flatter than the former.
  • FIG. 4 shows a schematic structural diagram of the planar transformer 40. As shown in FIG. 4, the planar transformer 40 includes a magnetic core 41 and a PCB winding plate 42.
  • the embodiment of the present application does not limit the material and shape of the magnetic core 41.
  • the shape of the magnetic core 41 may be EE type, EI type, or RM type.
  • the winding post of the magnetic core 41 may be provided with a winding coil composed of a multilayer circuit board.
  • the magnetic core 41 in the planar transformer can be connected to the potential static point of the primary circuit of the power conversion circuit, or connected to the potential static point of the secondary circuit of the power conversion circuit, which is not limited in the embodiment of the application. .
  • the above-mentioned PCB winding board 42 includes the following windings:
  • the primary winding 51 the first end of the primary winding 51 is connected to the potential static point of the primary circuit of the power conversion circuit, such as the point of the primary working ground network. Wherein, starting from the first end of the primary winding is the first turn of the primary winding.
  • the potential static point of the primary circuit may also be the positive pole of the bus capacitor connected to the primary circuit, which is not limited in the embodiment of the application.
  • the secondary winding 52 the first end of the secondary winding 52 is connected to the potential static point of the secondary circuit of the power conversion circuit, such as the point of the secondary working ground network. Wherein, starting from the first end of the secondary winding is the first turn of the secondary winding.
  • the potential static point of the primary circuit can also be the positive pole of the secondary circuit connected to the secondary output filter capacitor, which is not limited in the embodiment of the present application.
  • the shielding winding 53 is arranged between the primary winding 51 and the secondary winding 52 to shield the electric field coupling between the primary winding and the secondary winding.
  • the first end of the shield winding 53 may be connected to a static potential point, for example, it may be connected to a static potential point of a primary circuit or a static potential point of a secondary winding.
  • the first end of the shielding winding 53 can be connected to the static point of potential via one or more of capacitance, resistance, and inductance.
  • the first end of the shielding winding 53 can be connected to the first turn of the primary circuit away from the primary circuit.
  • the second end of the shield winding 53 is suspended.
  • the compensation winding 54 is adjacent to the primary winding 51 or adjacent to the secondary winding 52, and the compensation winding 54 includes an N-turn coil. It should be understood that there is a gap between every two adjacent turns in the compensation winding 54. N is a positive number greater than 1.
  • the first end of the compensation winding 54 can be connected to a static potential point.
  • the first end of the compensation winding 54 can be connected to the static potential point of the primary circuit 51 or the potential static point of the secondary winding 52.
  • the first end of the compensation winding 54 may be the first turn of the compensation winding.
  • the first end of the compensation winding 54 may be connected to a potential static point via one or more of capacitance, resistance, and inductance.
  • the second end of the compensation winding 54 may be suspended, wherein the second end corresponds to one end of the last coil of the compensation winding 54.
  • the shield winding can shield the electric field coupling between the primary winding and the secondary winding, thereby suppressing
  • the common mode noise generated by the compensation winding will be offset with the common mode noise flowing to the secondary winding or the primary winding, thereby achieving the lowest common mode noise of the entire system.
  • the shield winding can reduce the noise current between the primary winding and the secondary winding, the total number of turns of the compensation winding can be reduced, based on the number of turns of the compensation winding required by the embodiment of the application Lowering helps the design and mass production consistency of PCB winding boards.
  • the embodiments of the present application can sufficiently suppress common mode noise, the embodiments of the present application can effectively reduce the conducted emission CE, and thus can reduce the input common mode inductance.
  • the embodiment of the present application adopts electromagnetic shielding technology, which can reduce the frequency coupling effect of the secondary winding on the primary winding, thereby reducing the radiated emission RE.
  • the power conversion circuit in the embodiments of the present application can reduce or even eliminate the Y capacitors connected to the primary circuit and the secondary circuit. Therefore, a safer power conversion circuit with small Y capacitors or even no Y capacitors can be provided, and the cost and volume of the power conversion circuit can be reduced.
  • the shield winding can shield the electric field coupling between the primary winding and the secondary winding, including the following two situations.
  • the shield winding when the first end of the shield winding is connected to the static potential of the primary circuit, the shield winding can shield the electric field of the primary winding from coupling to the secondary winding. At this time, the shield winding can be arranged close to the secondary winding, that is, adjacent to the secondary winding.
  • the shield winding when the first end of the shield winding is connected to the potential static point of the secondary circuit, the shield winding can shield the electric field of the secondary winding from coupling to the primary winding. At this time, the shield winding can be arranged close to the primary winding, that is, adjacent to the primary winding.
  • the first end of the shielding winding is connected to the potential static point of the primary circuit and is adjacent to the secondary winding as an example for description, but the embodiment of the present application is not limited to this. .
  • the shield winding is used to shield the electric field of the primary winding from coupling to the secondary winding, which means that the shield winding can shield the noise current coupled to the secondary winding from the primary winding.
  • the shield winding may shield the noise current directly coupled to the secondary winding by the primary winding, or shield the noise current coupled to the secondary winding through the turn-to-turn gap of the compensation winding, which is not limited in the embodiment of the present application.
  • the second end of the primary winding 51 may be connected to the primary switching tube in the primary circuit, for example, the primary switching tube 211 in FIG. 3, which is not limited in the embodiment of the present application.
  • the second end of the primary winding 51 may correspond to one end of the last coil (for example, the n1-th turn) of the primary winding 51.
  • the second end of the secondary winding 52 may be connected to the secondary rectifier tube in the secondary circuit, for example, the secondary rectifier tube 221 in FIG. 3, which is not limited in the embodiment of the present application.
  • the second end of the secondary winding 52 may correspond to one end of the last coil of the secondary winding 52 (for example, the n2-th turn).
  • the floating of the other end may mean that there is no electrical connection between the other end and any conductor, or the winding of the floating end cannot form a closed loop with the planar transformer or other components in the power conversion circuit.
  • the primary winding 51 may include at least one primary winding layer, and a coil of the primary winding may be provided in the at least one primary winding layer.
  • the secondary winding 52 may include at least one secondary winding layer, and a coil of the secondary winding may be provided in the at least one secondary winding layer.
  • the coil may be formed of a conductive layer.
  • the primary winding 51 may include at least one turn of the primary power winding, and/or an auxiliary winding connected to the primary circuit.
  • the auxiliary winding may refer to a winding that provides a low-power power supply for other circuits except the main power circuit in the power conversion circuit.
  • the aforementioned circuits other than the main power circuit may include, for example, driving, control, and detection circuits.
  • At least one primary winding layer of the primary winding 51 may be provided with a coil of the primary power winding. Wherein, when there are multiple coils of the primary power winding, the coils can be connected in series.
  • the at least one primary winding layer may also be provided with a coil of an auxiliary winding connected to the primary circuit.
  • the secondary winding 52 may include a power winding of at least one turn in a second, and/or an auxiliary winding connected to the primary circuit.
  • At least one secondary winding layer of the above-mentioned secondary winding 52 may be provided with a coil of the secondary power winding. Similar to the primary power winding, the coils may be connected in series.
  • the at least one secondary winding layer may also be provided with an auxiliary winding coil.
  • the shield winding 53 may include a shield winding layer.
  • the shielding winding layer includes a 1-turn winding formed of metal foil (for example, copper foil).
  • the shield winding layer is a 1-turn toroidal winding formed by a large-area block conductor.
  • the number of turns of the shielding winding 53 may also be less than 1 turn, which is not limited in the embodiment of the present application.
  • the compensation winding 54 may include a compensation winding layer including N-turn coils. Among them, N is a positive number greater than 1.
  • two windings are adjacent, which means that there are no other winding layers between the winding layers where the two windings are located.
  • the compensation winding 54 is adjacent to the primary winding 51 means that there are no other winding layers between the winding layer where the compensation winding 54 is located and at least one winding layer where the primary winding 51 is located.
  • FIG. 4 shows a schematic diagram of a half cross-section of the PCB winding plate 42.
  • the section is located in the zr plane formed by the z-axis and the r-axis, where the z-axis is perpendicular to the plane where the surface of the PCB winding plate is located (for example, it can also be called the first plane), and the r-axis is perpendicular to the z-axis and points to the PCB The direction of the center of the winding plate. That is, the zr plane is perpendicular to the first plane.
  • Figures 5 to 13 below show schematic cross-sectional views of planar transformers.
  • the primary winding 51, the secondary winding 52, and the shield winding 53 are all located in the above-mentioned cross section, and the projection of the primary winding 51 along the z-axis on the first plane and the secondary winding 52 along the z-axis The projections on the first plane are all located within the projections of the shield winding 53 on the first plane along the z-axis. In this way, the shield winding can completely shield the electric field coupling between the primary winding 51 and the secondary winding 52.
  • the primary winding 51, the secondary winding 52, and the shielding winding 53 are all located in the above-mentioned cross-section, and the primary winding 51 is projected along the z-axis on the first plane or the secondary winding 52 is along the z-axis
  • the projection on the first plane is within the projection of the shield winding 53 on the first plane along the z axis. This is easy to achieve in the process, and for the electric field coupling between the primary winding 51 and the secondary winding 52, the shielding winding can achieve a better shielding effect.
  • FIG. 5 and 6 respectively show an example of winding coils in the PCB winding plate.
  • the first end of the shield winding is connected to the potential static point of the primary circuit of the power conversion circuit, such as the point of the primary working ground network.
  • the same reference signs have the same or similar meanings, and details are not repeated here.
  • the compensation winding 54 is adjacent to the secondary winding 52, and the shield winding 53 may be adjacent to the primary winding 51, or the shield winding 53 may be adjacent to both the primary winding 51 and the secondary winding 52.
  • the planar transformer shown in FIG. 5 includes two shield windings, one of which is adjacent to both the primary winding 51 and the secondary winding 52, and one of which is adjacent to the primary winding 51 and the compensation winding.
  • the first end of the compensation winding 54 is connected to the potential static point of the primary circuit, wherein the first end of the compensation winding starts to be the first turn of the compensation winding.
  • the second end of the compensation winding 54 may be suspended, wherein the second end corresponds to one end of the last coil (ie, the Nth turn) of the compensation winding 54.
  • the compensation winding 54 is adjacent to the aforementioned primary winding 51, and the shield winding 53 may be adjacent to the secondary winding 52, or the shield winding 53 may be adjacent to both the primary winding 51 and the secondary winding 52.
  • the planar transformer shown in FIG. 6 includes two shield windings, one of which is adjacent to both the primary winding 51 and the secondary winding 52, and one of which is adjacent to the secondary winding 52 and the compensation winding 54.
  • the first end of the compensation winding 54 is connected to the potential static point of the secondary circuit, wherein the first end of the compensation winding starts to be the first turn of the compensation winding.
  • the second end of the compensation winding 54 may be suspended, wherein the second end corresponds to one end of the last coil (ie, the Nth turn) of the compensation winding 54.
  • the shield winding when the shield winding is adjacent to the primary winding and the secondary winding, the shield winding can shield the noise current directly coupled to the secondary winding from the primary winding. When the shield winding is adjacent to the compensation winding, the shield winding can shield the noise current of the primary winding coupled to the secondary winding through the inter-turn gap of the compensation winding.
  • the shielding winding can be arranged between the primary winding and the secondary winding respectively. Shield the electric field coupling of the primary winding to the secondary winding. Therefore, in the embodiment of the present application, the number of shielding windings may be one, two, or more, which is not limited in the embodiment of the present application.
  • the number of compensation winding 54 may be at least one (for example, one, two or more), which is not limited in the embodiment of the present application. When the number of compensation windings is greater than or equal to two, the connection modes of the at least two compensation windings are similar.
  • the relative positions of the primary winding 51 and the secondary winding 52 may include the following three types.
  • the first type the primary winding 51 can be arranged on both sides of the secondary winding 52, that is, a part of the primary winding layer in the primary winding 51 is arranged on one side of the secondary winding 52, and the other part of the primary winding layer is arranged on the secondary winding
  • the other side of 52 forms a sandwich structure similar to a "sandwich". In this way, the high-frequency eddy current loss and leakage inductance of the winding can be reduced.
  • the second type the secondary winding 52 can be arranged on both sides of the primary winding 51.
  • the third type all the primary winding layers included in the primary winding 51 are arranged on one side of all the winding layers of the secondary winding 52, such as the upper side or the lower side.
  • the shielding winding 53 may include two shielding winding layers, which are arranged separately Between adjacent primary and secondary winding layers.
  • the shield winding 53 may include a shield winding layer.
  • FIG. 7 to 11 show some possible examples of winding coils in the embodiments of the present application.
  • FIG. 5, FIG. 6 and FIG. 7 are an example of the above-mentioned first position
  • FIG. 8 is an example of the above-mentioned second position
  • FIGS. 9-11 are an example of the above-mentioned third position.
  • FIGS. 7 to 11 are only examples, and the embodiments of the present application are not limited thereto.
  • the same reference numerals in FIG. 7 to FIG. 11 as those in FIG. 5 or FIG. 6 have the same or similar meanings, and for the sake of brevity, they will not be repeated here.
  • the primary winding 51 may include an auxiliary winding 511 and a primary power winding 512.
  • the secondary winding 52 may include an auxiliary winding 511 and a secondary power winding 522.
  • the primary winding 51 of the planar transformer is arranged on both sides of the secondary winding 52.
  • the first end of the compensation winding 54 is connected to the static potential of the primary circuit of the power conversion circuit, and the compensation winding 54 is adjacent to the secondary winding 52.
  • the first layer and the last layer of the PCB winding board of the planar transformer are respectively auxiliary winding layers, but the embodiment of the present application is not limited thereto.
  • the secondary winding 52 of the planar transformer is arranged on both sides of the primary winding 51.
  • the first end of the compensation winding 54 is connected to the static potential of the primary circuit of the power conversion circuit, and the compensation winding 54 is adjacent to the secondary winding 52.
  • the coil of the primary power winding and the coil of the auxiliary winding may be arranged on the same layer, and the coil of the secondary power winding may be arranged on the same layer as the coil of the auxiliary winding, but the embodiment of the present application is not limited to this.
  • all the primary winding layers included in the primary winding 51 are arranged on one side of all the winding layers of the secondary winding 52, such as the lower side.
  • the first end of the compensation winding 54 is connected to the static potential of the primary circuit of the power conversion circuit, and the compensation winding 54 is adjacent to the secondary winding 52.
  • the last layer (such as the bottom layer) of the PCB winding plate of the planar transformer is the auxiliary winding layer, but the embodiment of the present application is not limited to this.
  • the difference from the planar transformer shown in FIG. 9 is that the first end of the compensation winding 54 shown in FIG. 10 is connected to the potential static point of the secondary circuit of the power conversion circuit, and the compensation winding 54 is adjacent to the primary winding 51.
  • the compensation winding 54 in the planar transformer shown in FIG. 9 is arranged adjacent to the secondary winding 52 and close to the side of the primary winding 51.
  • the difference from the planar transformer shown in FIG. 9 is that the compensation winding 54 in the planar transformer shown in FIG. 11 is arranged adjacent to the secondary winding 52 and away from the primary winding 51.
  • connection modes of the windings in FIGS. 7 to 11 can be referred to the descriptions in FIGS. 4 to 6. For brevity, details are not repeated here.
  • the compensation winding 54 is adjacent to the first winding layer in the first winding, wherein the first winding is a primary winding adjacent to the compensation winding, or adjacent to the compensation winding The secondary winding.
  • the number of turns of the compensation winding 54 is related to the first winding layer, that is, is related to the primary winding layer or the secondary winding layer adjacent to the compensation winding 54.
  • the first winding layer is provided with the Nsth turn to the Ns+B-1th turn of the first winding, where N satisfies the following conditions:
  • the induced voltage generated by the Nb-turn coil is equal to the induced voltage generated by the first winding
  • C is a real number greater than 0
  • Nb, Ns, and B are positive numbers.
  • the number of turns N, Nb, Ns, or B of the coil may be an integer, or not an integer.
  • the number of turns of the coil may be 3 turns, 1.5 turns, or 2.4 turns, but The embodiments of the present application are not limited to this.
  • FIG. 12 and FIG. 13 are only examples, but the embodiments of the present application are not limited thereto.
  • the number of turns of the compensation winding 54 is related to Nb.
  • the compensation winding 54 includes a Nb-turn coil
  • the average value of the induced voltage generated by the Nb-turn coil is equal to the average value of the induced voltage generated by the secondary winding.
  • the value of Nb mainly depends on the voltage on the secondary winding 52 adjacent to it.
  • FIG. 12 shows an example of the secondary winding 52 and the compensation winding 54 when the compensation winding 54 is adjacent to the secondary winding.
  • the secondary winding 52 includes a 4-turn coil and two ends. Among them, the end connected to the static point of the secondary circuit is the first end, and the end connected to the secondary rectifier is the second end.
  • the coil starting from the first end as the first-turn coil, and so on, the following ones are the second-turn coil, the third-turn coil, and the fourth-turn coil.
  • Embodiment of the present application is also defined immediately compensating winding turns of the secondary winding 54 of the first 52 N x turns.
  • Nb The theoretical value of the number of turns of the compensation winding used to balance the induced voltage generated by the secondary winding is Nb.
  • Nb can be determined according to the following formula:
  • FIG. 13 shows another example of the secondary winding 52 and the compensation winding 54.
  • the secondary winding 52 includes an Nx +n- turn coil and two ends. Among them, the end connected to the static point of the secondary circuit is the first end, and the end connected to the secondary rectifier is the second end.
  • the coil starting from the first end as the first-turn coil, and so on, the latter are respectively the second-turn coil, to the N x+n-th coil.
  • the primary winding layer adjacent to the compensation winding 54 may not only include a 1-turn coil, but may also include a B-turn coil.
  • B can be a real number greater than 1.
  • the compensation winding 54 is arranged next to the N x turn to N x +B-1 turn coil in the secondary winding 52.
  • Nb The theoretical value of the number of turns of the compensation winding used to balance the induced voltage generated by the secondary winding is Nb.
  • Nb can be determined according to the following formula:
  • the number of turns of the winding is subject to certain restrictions. Therefore, the coil with the smaller number of turns in the secondary winding can be preferentially arranged adjacent to the compensation winding, which can further reduce the value of Nb.
  • C may be a real number greater than zero. That is, N and Nb can be equal, and N can also be greater than Nb or less than Nb, which is not limited in the embodiment of the present application.
  • the winding direction of the shielding winding 53 is the same as the winding direction of the compensation winding 54, but the embodiment of the present application is not limited thereto.
  • the secondary circuit includes a secondary rectifier tube and a secondary filter.
  • the secondary rectifier tube When the secondary rectifier tube is connected to the negative electrode of the secondary filter capacitor, the first end of the compensation winding 54 and the first end of the primary winding 51 One end is a different name.
  • N may be greater than or equal to Nb.
  • the primary winding 51 includes a primary power winding
  • the first end of the primary power winding is connected to the potential static point of the primary circuit of the power conversion circuit, and the first end of the compensation winding 54 is connected to the primary power winding.
  • the first end is a synonymous end.
  • FIG. 14 shows a schematic diagram of the common mode noise path in the power conversion circuit of the embodiment of the present application.
  • the first end of the primary winding 51 can be connected to the primary filter capacitor 212, and the second end is connected to the primary switching tube 211.
  • the voltage jump of the primary winding 51 can refer to the primary switching tube 211 at high frequency.
  • the first end of the secondary winding 52 can be connected to the secondary filter capacitor 222, and the second end is connected to the secondary switch tube 221.
  • the voltage jump of the secondary winding 52 can mean that the secondary switch tube 221 is turned on at high frequency. Or the jump voltage Vs generated during turn-off.
  • the secondary rectifier tube 221 is connected to the negative electrode of the secondary filter capacitor 222.
  • the first end of the shielding winding 53 can be connected to the primary filter capacitor 212
  • the second end of the compensation winding 54 can be connected to the primary filter capacitor 212
  • the second end of the compensation winding 54 can be connected to the primary filter capacitor 212
  • the second end of the compensation winding 54 can be connected to the primary filter capacitor 212.
  • Figure 14 shows a possible common mode noise path based on the flyback converter when the planar transformer does not include the shield winding.
  • One is the jump voltage Vp of the primary circuit coupled to the noise current flowing to the ground +Ips of the secondary winding.
  • the second is the noise current +Isp flowing to the ground generated by the jump voltage Vs in the secondary circuit
  • the third is the induced current -Id flowing to the primary winding generated by the compensation winding
  • the fourth is other noise paths in the flyback converter system.
  • the generated noise current flowing to the ground for example, is the jump voltage Vp directly coupled to +Id1 of the LISN through the spatial coupling capacitor Cpe.
  • the noise current Ips may include the potential jump Vp of the primary winding and may also be coupled to the secondary winding through the interturn gap of the compensation winding to form a noise current, or The potential jump Vp of the primary winding is directly coupled to the noise current formed by the secondary winding.
  • the shielding winding can reduce or even eliminate the noise current flowing to the ground that is coupled to the secondary winding by the jump voltage Vp in the primary circuit.
  • the compensation winding at least needs to cancel the noise current (Isp+Id1), so the compensation winding needs to cancel the noise current It is greater than the common mode noise generated by the secondary winding, so the above-mentioned number of coil turns Nb can be positively compensated to further obtain the number of coil turns N of the compensation winding 54.
  • N can satisfy the following conditions:
  • C1 is a real number greater than 1.
  • the shielding winding can reduce or even eliminate the jump voltage Vp in the primary circuit coupled to the noise current Isp flowing to the secondary winding to the ground, the setting of the shielding winding can reduce the value of C1, that is, reduce the turns of the compensation winding number.
  • C1 can be determined according to the potential jump of the primary winding through the spatial coupling capacitor coupled to the noise current of the line impedance stabilization network LISN.
  • C1 can also be determined according to the PCB manufacturing process tolerance.
  • the manufacturing process tolerance may include at least one of the thickness tolerance of the interlayer dielectric, the line width tolerance of the compensation winding, and the dielectric constant tolerance of the PCB board.
  • C1 when realizing the cancellation of the common mode noise of the transformer itself, considering the shielding winding and/or the process tolerance of the PCB, C1 can be set to 1.3 to 1.8.
  • the corrected N-correction can be shown in the following formula (4):
  • N-correction [3.9,5.4].
  • the cancellation of Id1 needs to be considered.
  • the spatial coupling capacitor When considering the potential jump of the primary power winding, it is coupled to the line impedance stabilization network LISN through the spatial coupling capacitor to form noise
  • C1 can be further compensated to 120% on the basis of 1.3 to 1.8, that is, [1.3*1.2 to 1.8*1.2], that is, 1.56 to 2.16.
  • the corrected N-correction can be shown in the following formula (7):
  • N-correction [4.68,6.48].
  • the secondary circuit includes a secondary rectifier tube and a secondary filter capacitor.
  • the secondary rectifier tube When the secondary rectifier tube is connected to the anode of the secondary filter capacitor, the first end of the compensation winding 54 and the primary winding 51 The first ends are mutually homonymous ends.
  • N may be less than or equal to Nb.
  • the primary winding 51 includes a primary power winding
  • the first end of the primary power winding is connected to the potential static point of the primary circuit of the power conversion circuit
  • the first end of the compensation winding 54 is connected to the primary power winding.
  • the first end of is the end with the same name.
  • FIG. 16 shows a schematic diagram of the common mode noise path in the power conversion circuit of the embodiment of the present application.
  • the first end of the primary winding 51 can be connected to the primary filter capacitor 212, and the second end is connected to the primary switching tube 211.
  • the voltage jump of the primary winding 51 can refer to the primary switching tube 211 at high frequency.
  • the first end of the secondary winding 52 can be connected to the secondary filter capacitor 222, and the second end is connected to the secondary switch tube 221.
  • the voltage jump of the secondary winding 52 can mean that the secondary switch tube 221 is turned on at high frequency. Or the jump voltage Vs generated during turn-off.
  • the secondary rectifier tube 221 is connected to the anode of the secondary filter capacitor 222.
  • the first end of the shielding winding 53 can be connected to the primary filter capacitor 212
  • the second end of the compensation winding 54 can be connected to the primary filter capacitor 212
  • the second end of the compensation winding 54 can be connected to the primary filter capacitor 212
  • the second end of the compensation winding 54 can be connected to the primary filter capacitor 212.
  • Figure 16 shows a possible common mode noise path based on the flyback converter when the planar transformer does not include the shield winding.
  • One is the jump voltage Vp of the primary circuit coupled to the noise current flowing to the ground +Idps of the secondary winding.
  • the second is the noise current -Isp flowing to the primary winding generated by the jump voltage Vs in the secondary circuit
  • the third is the induced current +Id flowing to the secondary winding generated by the compensation winding
  • the fourth is the other in the flyback converter system.
  • the noise current flowing to the ground generated by the noise path is, for example, the jump voltage Vp directly coupled to +Id1 of the LISN through the spatial coupling capacitor Cpe.
  • the noise current +Ips may include the jump voltage Vp of the primary circuit coupled to the secondary winding through the interturn gap of the compensation winding to form a noise current, or the potential jump Vp of the primary winding Directly coupled to the noise current formed by the secondary winding.
  • the shielding winding can reduce or even eliminate the noise current flowing to the ground that is coupled to the secondary winding by the jump voltage Vp in the primary circuit.
  • the compensation winding at least needs to cancel the noise current (Isp-Id1), so the compensation winding needs to cancel the noise current It is smaller than the common mode noise generated by the secondary winding, so the above-mentioned number of coil turns Nb can be negatively compensated to further obtain the number of coil turns N of the compensation winding 54.
  • N can satisfy the following conditions:
  • C2 is a real number with a value range of (0, 1).
  • the shield winding can reduce or even eliminate the noise current Id1 flowing to the ground from the jump voltage Vp in the primary circuit coupled to the secondary winding
  • the setting of the shield winding can reduce the take of C2. Value, that is, reduce the number of turns of the compensation winding.
  • C2 can be determined according to the potential jump of the primary winding through the spatial coupling capacitor coupled to the noise current of the line impedance stabilization network LISN.
  • C2 can also be determined according to the PCB manufacturing process tolerance.
  • the manufacturing process tolerance may include at least one of the thickness tolerance of the interlayer dielectric, the line width tolerance of the compensation winding, and the dielectric constant tolerance of the PCB board.
  • the disclosed system, device, and method may be implemented in other ways.
  • the device embodiments described above are only illustrative.
  • the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or It can be integrated into another system, or some features can be ignored or not implemented.
  • the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.
  • each unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.
  • the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium.
  • the technical solution of this application essentially or the part that contributes to the existing technology or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including Several instructions are used to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application.
  • the aforementioned storage media include: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program code .

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Abstract

本申请提供一种平面变压器、电源转换电路以及适配器，能够提高噪声抑制的性能。该平面变压器，包括磁芯和印刷电路板PCB绕组板，其中所述PCB绕组板包括：初级绕组、次级绕组、屏蔽绕组和补偿绕组。本申请实施例中，通过在平面变压器的初级绕组和次级绕组之间设置屏蔽绕组和具有多匝线圈的补偿绕组，该屏蔽绕组能够屏蔽初级绕组与次级绕组之间的电场耦合，从而抑制初级绕组与次级绕组之间的噪声电流，该补偿绕组产生的共模噪声会与流向次级绕组或者流向初级绕组的共模噪声抵消，从而实现整个系统的共模噪声最低。

Description

平面变压器、电源转换电路以及适配器
本申请要求于2019年6月14日提交中国专利局、申请号为201910518152.3、申请名称为“平面变压器、电源转换电路以及适配器”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电路领域，并且更具体地，涉及一种平面变压器、电压转换电路以及适配器。
背景技术
开关电源以其效率高、体积小、输出稳定性好的优点而迅速发展起来。但是开关电源在工作过程中的遭受噪声干扰的问题非常突出。开关电源遭受的噪声包括来自外界的噪声、自身开关器件关断和导通产生的噪声、整流二极管反向恢复产生的噪声、自身电路中的电容/电感/导线产生的噪声，这些噪声信号会沿着电路网络传导和辐射到用电设备，并会导致该用电设备遭受电磁干扰(electro-magnetic interference,EMI)。因而开关电源对噪声抑制的要求非常严格。
开关电源遭受的噪声包括共模噪声，共模噪声主要包括由开关电源电路各参数间相互作用而产生的对参考地之间的噪声，如何降低甚至消除开关电源的共模噪声是业界非常关注的问题。
发明内容
本申请提供一种平面变压器、电源转换电路以及适配器，能够提高噪声抑制的性能。
第一方面，提供了一种平面变压器，包括磁芯和印刷电路板PCB绕组板，其中所述PCB绕组板包括：
初级绕组，所述初级绕组的第一端头连接电源转换电路的初级电路的电位静点，其中，从所述初级绕组的第一端头开始为所述初级绕组的第1匝线圈；
次级绕组，所述次级绕组的第一端头连接所述电源转换电路的次级电路的电位静点，其中，从所述次级绕组的第一端头开始为所述次级绕组的第1匝线圈；
屏蔽绕组，设置于所述初级绕组和所述次级绕组之间，用于屏蔽所述初级绕组与所述次级绕组之间的电场耦合；
补偿绕组，与所述初级绕组相邻，或与所述次级绕组相邻，所述补偿绕组包括N匝线圈，N为大于1的正数。
本申请实施例中，通过在平面变压器的初级绕组和次级绕组之间设置屏蔽绕组和具有多匝线圈的补偿绕组，该屏蔽绕组能够屏蔽初级绕组与次级绕组之间的电场耦合，从而抑制初级绕组与次级绕组之间的噪声电流，该补偿绕组产生的共模噪声会与流向次级绕组或 者流向初级绕组的共模噪声抵消，从而实现整个系统的共模噪声最低。由于在本申请实施例中，屏蔽绕组能够减小初级绕组与次级绕组之间的噪声电流，因此补偿绕组的总匝数可以减小，基于此本申请实施例需要的补偿绕组的线圈匝数降低，有助于PCB绕组板的设计和量产一致性。
进一步的，由于本申请实施例能够充分抑制共模噪声，本申请实施例能够有效降低传导发射CE，进而能够减小输入共模电感。另外，对于高频段(比如30M以上)，本申请实施例采用电磁屏蔽技术，能够降低次级绕组对初级绕组的频点耦合影响，进而降低辐射发射RE。
另外，本申请实施例由于能够充分抑制共模噪声，并有效降低CE和RE，因此本申请实施例中的电源转换电路可以减小甚至取消跨接在初级电路和次级电路上的Y电容，从而能够提供小Y电容甚至无Y电容的安全性更高的电源转换电路，并降低电源转换电路的成本和体积。
本申请实施例中，屏蔽绕组能够屏蔽初级绕组与次级绕组之间的电场耦合，包括如下两种情况。
第一种情况：当屏蔽绕组的第一端头连接初级电路的电位静点时，屏蔽绕组能够屏蔽初级绕组的电场向次级绕组耦合。此时，屏蔽绕组可以靠近次级绕组设置，即与次级绕组相邻。
第二种情况：当屏蔽绕组的第一端头连接次级电路的电位静点时，屏蔽绕组能够屏蔽次级绕组的电场向初级绕组耦合。此时，屏蔽绕组可以靠近初级绕组设置，即与初级绕组相邻。
作为示例，屏蔽绕组用于屏蔽初级绕组的电场向次级绕组耦合，指的是屏蔽绕组能够屏蔽初级绕组耦合到次级绕组的噪声电流。示例性的，屏蔽绕组可以屏蔽初级绕组直接耦合到次级绕组的噪声电流，或者屏蔽初级绕组通过补偿绕组的匝间间隙耦合到次级绕组的噪声电流，本申请实施例对此不作限定。
结合第一方面，在第一方面的某些实现方式中，所述屏蔽绕组与所述初级绕组相邻。对应的，此时屏蔽绕组可以与初级绕组相邻，或者屏蔽绕组与初级绕组和次级绕组均相邻。其中，该补偿绕组的第一端头连接该初级电路的电位静点，第二端头可以悬空。
或者，屏蔽绕组可以与所述次级绕组相邻。对应的，此时屏蔽绕组可以与次级绕组相邻，或者屏蔽绕组与初级绕组和次级绕组均相邻。其中，该补偿绕组的第一端头连接该次级电路的电位静点，第二端头可以悬空。
需要说明的是，当屏蔽绕组与初级绕组和次级绕组相邻时，屏蔽绕组可以屏蔽初级绕组直接耦合到次级绕组的噪声电流。当屏蔽绕组与补偿绕组相邻时，屏蔽绕组能够屏蔽初级绕组通过补偿绕组的匝间间隙耦合到次级绕组的噪声电流。
因此，当本申请实施例将初级绕组设置在次级绕组的两侧，或者将次级绕组设置在初级绕组的两侧时，可以分别在初级绕组和次级绕组之间均设置屏蔽绕组，来屏蔽初级绕组对次级绕组的电场耦合。进一步的，本申请实施例中，屏蔽绕组的个数可以为一个，两个，或者多个，本申请实施例对此不作限定。
在一些可选的实施例中，补偿绕组的个数可以为至少一个(例如一个、两个或多个)，本申请实施例对此不作限定。
结合第一方面，在第一方面的某些实现方式中，所述初级绕组沿z轴在第一平面上的投影和/或所述次级绕组沿所述z轴在所述第一平面上的投影位于所述屏蔽绕组沿所述z轴在所述第一平面上的投影内，所述第一平面为所述PCB绕组板的表面所在的平面，所述z轴垂直于所述第一平面。
其中，所述PCB绕组板在所述第一平面上的投影为一个环形，截面垂直于所述第一平面，所述初级绕组、所述次级绕组以及所述屏蔽绕组均位于所述截面内。
这样，屏蔽绕组能够较好的屏蔽初级绕组与次级绕组之间的电场耦合。
结合第一方面，在第一方面的某些实现方式中，所述补偿绕组与所述次级绕组相邻，所述补偿绕组的第一端头连接所述初级电路的电位静点。
结合第一方面，在第一方面的某些实现方式中，所述补偿绕组与所述初级绕组相邻，所述补偿绕组的第一端头连接所述次级电路的电位静点。
结合第一方面，在第一方面的某些实现方式中，所述次级电路中包括次级整流管和次级滤波电容，当所述次级整流管连接所述次级滤波电容的负极时，所述补偿绕组的第一端头和所述初级绕组的第一端头互为异名端。
结合第一方面，在第一方面的某些实现方式中，所述次级电路中包括次级整流管和次级滤波电容，当所述次级整流管连接所述次级滤波电容的正极时，所述补偿绕组的第一端头和所述初级绕组的第一端头互为同名端。
结合第一方面，在第一方面的某些实现方式中，所述补偿绕组与第一绕组中的第一绕组层相邻，其中，所述第一绕组为与所述补偿绕组相邻的初级绕组，或与所述补偿绕组相邻的次级绕组，所述第一绕组层上设置有所述第一绕组的第Ns匝至第Ns+B-1匝线圈，其中，N满足如下条件：
N＝Nb*C，Nb＝2×Ns+B-2，
其中，Nb匝线圈产生的感应电压与所述第一绕组产生的感应电压相等，C为大于0的实数，Nb、Ns、B为正数。
在实际工程设计中，受到PCB绕组绕线通道的空间限制，绕组的匝数受到一定的限制。因此，临近补偿绕组可以优先布置次级绕组中较小次序匝数的线圈，这样能够进一步减小Nb值的大小。
结合第一方面，在第一方面的某些实现方式中，C的取值范围为[1.56，2.16]或(0,1]。
作为示例，在所述次级电路中包括次级整流管和次级滤波电容，当所述次级整流管连接所述次级滤波电容的负极时，所述补偿绕组的第一端头和所述初级绕组的第一端头互为异名端的情况下，C取值大于1。
因此，在这种情况下，补偿绕组需要抵消的噪声电流大于次级绕组产生的共模噪声，可以通过设置C的取值(大于1)对上述线圈匝数Nb进行正补偿，以进一步获得补偿绕组54的线圈匝数N。由于屏蔽绕组能够减小甚至消除初级电路中的跳变电压Vp耦合到次级绕组的流向地的噪声电流Isp，因此，通过设置屏蔽绕组可以减小C的取值，即减小补偿绕组的匝数。一些可选的实施例中，C的取值范围为[1.56，2.16]。
作为示例，在所述次级电路中包括次级整流管和次级滤波电容，当所述次级整流管连接所述次级滤波电容的正极时，所述补偿绕组的第一端头和所述初级绕组的第一端头互为同名端的情况下，C的取值范围为(0,1]。
因此，在这种情况情况下，补偿绕组需要抵消的噪声电流小于次级绕组产生的共模噪声，可以通过设置C的取值(在0～1之间)上述线圈匝数Nb进行负补偿，以进一步获得补偿绕组54的线圈匝数N。由于屏蔽绕组能够减小甚至消除初级电路中的跳变电压Vp耦合到次级绕组的流向地的噪声电流Id1，因此，通过设置屏蔽绕组可以减小C的取值，即减小补偿绕组的匝数。
可选的，C的取值可以根据所述初级绕组的电位跳变通过空间耦合电容耦合到线路阻抗稳定网络LISN的噪声电流来确定。
结合第一方面，在第一方面的某些实现方式中，所述补偿绕组的第二端头悬空。
结合第一方面，在第一方面的某些实现方式中，所述初级电路的电位静点包括所述初级电路中连接母线电容正极或初级工作地网络的点，所述次级电路的电位静点包括所述次级电路中连接次级输出滤波电容的正极或次级工作地网络的点，其中，所述电位静点在电路工作过程中电压无跳变。
结合第一方面，在第一方面的某些实现方式中，所述初级绕组包含至少1匝初级功率绕组，和/或与所述初级电路连接的辅助绕组。
结合第一方面，在第一方面的某些实现方式中，所述次级绕组包含至少1匝次级功率绕组，和/或，与所述初级电路连接的辅助绕组。
结合第一方面，在第一方面的某些实现方式中，所述屏蔽绕组的第一端头连接所述初级电路的电位静点或者所述次级绕组的电位静点，且所述屏蔽绕组的第二端头悬空。
第二方面，提供了一种电源转换电路，包括：如第一方面以及第一方面的任一可能的实现方式中的平面变压器、初级电路以及次级电路，所述平面变压器设置在所述初级电路和所述次级电路之间。
第三方面，提供了一种适配器，包括第二方面所述的电源转换电路。
附图说明
图1是本申请实施例的一种应用场景的示意图。
图2是本申请实施例的电源转换电路的示意图。
图3是本申请实施例的一种电源转换电路的示意图。
图4是本申请实施例的一种平面变压器的示意图。
图5是本申请实施例的一种平面变压器的截面示意图。
图6是本申请实施例的另一种平面变压器的截面示意图。
图7是本申请实施例的另一种平面变压器的截面示意图。
图8是本申请实施例的另一种平面变压器的截面示意图。
图9是本申请实施例的另一种平面变压器的截面示意图。
图10是本申请实施例的另一种平面变压器的截面示意图。
图11是本申请实施例的另一种平面变压器的截面示意图。
图12是本申请实施例中的次级绕组和补偿绕组的一个示例。
图13是本申请实施例中的次级绕组和补偿绕组的另一个示例。
图14是电源转换电路中的共模噪声路径的一个示意图。
图15是平面变压器中的共模噪声路径的一个示意图。
图16是电源转换电路中的共模噪声路径的一个示意图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
为了便于了解本申请实施例，下面首先介绍本申请实施例涉及的一些术语。
平面变压器(planar transformer)：区别于传统的变压器结构，平面变压器的磁芯、绕组是平面结构。磁芯一般采用扁平化的磁芯结构，比如小尺寸的E型磁芯结构或RM型磁芯结构。绕组一般采用多层印刷电路板(printed circuit board，PCB)迭绕而成，这种设计有较低的直流电阻、较小的漏感和分布电容，高度很小，可以有较高的工作频率。
反激变换器(flyback converter)：广泛应用于交流直流(AC/DC)和直流直流(DC/DC)转换，是较为常见的小功率开关电源变换器，具有结构简单，成本低廉的优点。其核心部件包括功率开关管、变压器、二极管和电容。功率开关管由脉冲宽度调制控制，通过闭合与导通在变压器初级线圈中产生高频方波信号，再感应耦合到变压器的次级线圈，实现能量的传递。通过次级电路的二极管和电容的滤波整流作用，在输出端得到稳定的直流输出。
共模噪声：共模噪声又称为非对称噪声或线路对地的噪声，使用交流电源的电气设备中都存在这种噪声，共模噪声的电流在两个输电线上以相同的方向流动且对地的相位保持相同，并通过地线返回。共模噪声可以通过在共模电感或者在两个输电线和地之间使用Y电容进行抑制。
电位静点：在电路网络中，该网络节点上的电压电位幅值在电路工作过程中保持相对恒定，没有高频的跳跃或者震荡。比如：反激变换器初级侧电路整流后的滤波电容和次级侧电路整流后的滤波电容，这些电容的正极或者负极及直接与其相连接的网络节点即为电位静点。
本申请提供了一种平面变压器、电源转换电路以及适配器。其中，上述变压器可以设置于电源转换电路中，上述电源转换电路可以设置于适配器中。
具体地，适配器可以应用于为设备充电或供电的场景。例如，图1示出了本申请实施例的一种可能的应用场景。如图1所示，该应用场景包括外部电源11、适配器12以及待充电设备13。例如，上述待充电设备13可以包括蜂窝电话、笔记本电脑、电池等，本申请实施例对此并不限定。通常情况下，适配器12可以与外部电源11连接，适配器12包括的电源转换电路用于将外部电源11提供的较高电压转换为符合待充电设备13充电或供电标准的较低电压，并为待充电设备13进行充电或供电。
本申请实施例的提供的平面变压器能够降低工作时产生的噪声。上述噪声可以包括共模噪声。上述电源转换电路可以是开关电源变换器，例如，开关电源变换器可以包括反激变换器。共模噪声主要由开关电源电路各参数间相互作用而产生的对参考地之间的噪声，下面结合图2和图3，介绍电源转换电路20中的共模噪声产生和传输的机理。
如图2所示，电源转换电路20通常包括初级电路21、次级电路22以及变压器23。如图3所示，初级电路通常包括初级开关管211、初级滤波电容212。进一步地，初级电路还包括整流电路。上述初级开关管211也可以称为功率开关管。次级电路22通常包括次级整流管221和次级滤波电容222。变压器23包括初级绕组231、磁芯以及次级绕组232。初级绕组231可以与初级开关管211以及初级滤波电容212相连，次级绕组232可 以与次级整流管221以及次级滤波电容222相连。初级滤波电容212和次级滤波电容222通常采用电解电容。
通常情况下，与初级滤波电容212的两端中的任意一端相连的节点为初级电路的电位静点，或者，初级电路的地节点也可以为初级电路的电位静点。与次级滤波电容222的两端中的任意一端相连的节点为次级电路的电位静点。
在电源转换电路20工作时，外部电源11输入的交流电通过初级电路21的整流滤波之后，转变为稳定的高压直流电输入至变压器23的初级绕组231。与初级绕组231相连的初级开关管211通过高频导通与关断，将初级绕组231上的电压耦合到次级绕组232上。耦合到次级绕组232的电压通过次级电路22的整流滤波之后，向负载输出低压直流电，为负载充电或供电。其中，上述负载即上述待充电设备13。在上述电源转换电路20的工作过程中，初级开关管211由于高频的导通与关断，产生跳变电压Vp，次级整流管221由于高频的导通与关断，产生跳变电压Vs。
由于变压器的初级绕组231和次级绕组232之间存在寄生电容，跳变电压Vp和Vs通过上述寄生电容在电源转换电路中产生共模噪声。具体地，参见图3所示，上述寄生电容包括初级绕组对次级绕组之间的分布电容Cps和次级绕组对初级绕组的分布电容Csp。初级电路中的跳变电压Vp通过Cps产生流向地的噪声电流Ips，次级电路中的跳变电压Vs通过Csp产生流向地的噪声电流Isp。上述噪声电流Ips和噪声电流Isp即为共模噪声。
如何抑制上述共模噪声，是当前业界设计具有较强竞争力的适配器的难点之一。
需要说明的是，图3中还示出了线路阻抗稳定网络(Line Impedance Stabilization Network,LISN)电路，LISN电路是一种测试电路，用于检测电源转换电路工作时流入地的共模噪声电流，换句话说，可以认为流入LISN网络检测到的对地电流等效为电源转换电路产生的共模噪声。
针对上述问题，本申请实施例提出了一种具有较低共模噪声的平面变压器，采用该平面变压器的电源变换电路具有较高的噪声抑制性能，并且该电源转换电路的传导发射(conducted emission，CE)和辐射发射(radiation emission，RE)能够被降低。另外，本申请还提供了应用该平面变压器的电源变换电路，以及应用该电源变换电路的适配器。具体的，平面变压器、电源转换电路以及适配器可以参见图1至图3中的描述，为了简洁，这里不再赘述。
本申请实施例中提供的变压器主要由磁芯和绕组线圈组成。其中，绕组线圈可以是传统的铜线烧制，也可以是由多层PCB经过刻蚀而成。后者相对前者由于更加扁平化，所以一般被称为平面变压器。图4示出了平面变压器40的一种结构示意图。如图4所示，该平面变压器40包括磁芯41和PCB绕组板42。
本申请实施例对磁芯41的材质以及形状不作限定。例如，磁芯41的形状可以为EE型、EI型或者RM型。该磁芯41的绕线柱上可以设置有多层电路板构成的绕线线圈。
在一些可能的实现方式中，平面变压器中的磁芯41可以连接电源转换电路的初级电路的电位静点，或连接电源转换电路的次级电路的电位静点，本申请实施例对此不作限定。
如图4所示，上述PCB绕组板42包括以下绕组：
初级绕组51，该初级绕组51的第一端头连接电源转换电路的初级电路的电位静点，例如初级工作地网络的点。其中，从该初级绕组的第一端头开始为该初级绕组的第1匝线 圈。或者，初级电路的电位静点还可以为初级电路中连接母线电容正极，本申请实施例对此不作限定。
次级绕组52，该次级绕组52的第一端头连接电源转换电路的次级电路的电位静点，例如次级工作地网络的点。其中，从该次级绕组的第一端头开始为该次级绕组的第1匝线圈。或者，初级电路的电位静点还可以为所述次级电路中连接次级输出滤波电容的正极，本申请实施例对此不作限定。
屏蔽绕组53，设置于该初级绕组51和该次级绕组52之间，用于屏蔽初级绕组与次级绕组之间的电场耦合。
屏蔽绕组53的第一端头可以连接电位静点，例如，可以连接初级电路的电位静点或次级绕组的电位静点。或者，屏蔽绕组53的第一端头可以经电容、电阻、电感中的一个或多个连接电位静点，例如，屏蔽绕组53的第一端头可以连接初级电路的第1匝线圈远离初级电路的电位静点的一端，或者，连接次级电路的第1匝线圈远离次级电路的电位静点的一端。
屏蔽绕组53的第二端头悬空。
补偿绕组54，与该初级绕组相邻51，或与该次级绕组52相邻，该补偿绕组54包括N匝线圈。应当理解，补偿绕组54中每相邻两匝线圈之间具有间隙。N为大于1的正数。
补偿绕组54的第一端头可以连接电位静点。补偿绕组54的第一端头可以连接初级电路51的电位静点，也可以连接次级绕组52的电位静点。补偿绕组54的第一端头开始可以是该补偿绕组的第1匝线圈。或者，补偿绕组54的第一端头可以经电容、电阻、电感中的一个或多个连接电位静点。
可选的，补偿绕组54的第二端头可以悬空，其中，第二端头对应补偿绕组54的最后1匝线圈的一端。
本申请实施例中，通过在平面变压器的初级绕组和次级绕组之间设置屏蔽绕组和具有多匝线圈的补偿绕组，该屏蔽绕组能够屏蔽初级绕组与次级绕组之间的电场耦合，从而抑制初级绕组与次级绕组之间的噪声电流，该补偿绕组产生的共模噪声会与流向次级绕组或者流向初级绕组的共模噪声抵消，从而实现整个系统的共模噪声最低。由于在本申请实施例中，屏蔽绕组能够减小初级绕组与次级绕组之间的噪声电流，因此补偿绕组的总匝数可以减小，基于此本申请实施例需要的补偿绕组的线圈匝数降低，有助于PCB绕组板的设计和量产一致性。
进一步的，由于本申请实施例能够充分抑制共模噪声，本申请实施例能够有效降低传导发射CE，进而能够减小输入共模电感。另外，对于高频段(比如30M以上)，本申请实施例采用电磁屏蔽技术，能够降低次级绕组对初级绕组的频点耦合影响，进而降低辐射发射RE。
另外，本申请实施例由于能够充分抑制共模噪声，并有效降低CE和RE，因此本申请实施例中的电源转换电路可以减小甚至取消跨接在初级电路和次级电路上的Y电容，从而能够提供小Y电容甚至无Y电容的安全性更高的电源转换电路，并降低电源转换电路的成本和体积。
本申请实施例中，屏蔽绕组能够屏蔽初级绕组与次级绕组之间的电场耦合，包括如下两种情况。
第一种情况：当屏蔽绕组的第一端头连接初级电路的电位静点时，屏蔽绕组能够屏蔽初级绕组的电场向次级绕组耦合。此时，屏蔽绕组可以靠近次级绕组设置，即与次级绕组相邻。
第二种情况：当屏蔽绕组的第一端头连接次级电路的电位静点时，屏蔽绕组能够屏蔽次级绕组的电场向初级绕组耦合。此时，屏蔽绕组可以靠近初级绕组设置，即与初级绕组相邻。
在下文所述的实施例中，为了方面描述，以屏蔽绕组的第一端头连接初级电路的电位静点，并与次级绕组相邻为例进行描述，但是本申请实施例并不限于此。
屏蔽绕组用于屏蔽初级绕组的电场向次级绕组耦合，指的是屏蔽绕组能够屏蔽初级绕组耦合到次级绕组的噪声电流。作为示例，屏蔽绕组可以屏蔽初级绕组直接耦合到次级绕组的噪声电流，或者屏蔽初级绕组通过补偿绕组的匝间间隙耦合到次级绕组的噪声电流，本申请实施例对此不作限定。
本申请实施例中，初级绕组51的第二端头可以连接初级电路中的初级开关管，例如为图3中的初级开关管211，本申请实施例对此不作限定。其中，初级绕组51的第二端头可以对应于初级绕组51的最后1匝(比如第n1匝)线圈的一端。
本申请实施例中，次级绕组52的第二端头可以连接次级电路中的次级整流管，例如为图3中的次级整流管221，本申请实施例对此不作限定。其中，次级绕组52的第二端头可以对应于次级绕组52的最后1匝(比如第n2匝)线圈的一端。
本申请实施例中，另一端悬空可以指该另一端与任何导体之间不存在电连接，或者该一端悬空的绕组不能与平面变压器或电源转换电路中的其他部件一起形成闭合回路。
一些可能的实现方式，初级绕组51可以包括至少一个初级绕组层，该至少一个初级绕组层中可以设置有初级绕组的线圈。次级绕组52可以包括至少一个次级绕组层，该至少一个次级绕组层中可以设置有次级绕组的线圈。本申请实施例中，线圈可以采用导电层构成。
一些可选的实施例中，初级绕组51可以包括至少1匝初级功率绕组，和/或与该初级电路连接的辅助绕组。其中，该辅助绕组可以指在电源转换电路中为除主功率电路之外的其他电路提供小功率电源的绕组。上述除主功率电路之外的其他电路例如可以包括驱动、控制、检测等电路。
一些可能的实现方式中，上述初级绕组51的至少一个初级绕组层中可以设置有初级功率绕组的线圈。其中，当该初级功率绕组的线圈为多个时，该线圈可以相互串联。可选的，该至少一个初级绕组层中还可以设置与初级电路连接的辅助绕组的线圈。
一些可选的实施例，次级绕组52可以包括次至少1匝级功率绕组，和/或与初级电路连接的辅助绕组。上述次级绕组52的至少一个次级绕组层中可以设置有该次级功率绕组的线圈，与初级功率绕组类似，该线圈可以相互串联。可选的，该至少一个次级绕组层中还可以设置辅助绕组的线圈。
一些可能的实现方式，该屏蔽绕组53可以包括一个屏蔽绕组层。可选的，该屏蔽绕组层包括金属箔(例如铜箔)形成的1匝绕组。示例性的，该屏蔽绕组层为一个大面积块状导体形成的1匝环形绕组。
作为示例，屏蔽绕组53的匝数也可以小于1匝，本申请实施例对此不做限定。
一些可能的实现方式，该补偿绕组54可以包括一个补偿绕组层，该补偿绕组层中包括N匝线圈。其中，N为大于1的正数。
需要说明的是，本申请实施例中，两个绕组相邻，指的是该两个绕组所在的绕组层之间不存在其他绕组层。例如，补偿绕组54与初级绕组51相邻，是指该补偿绕组54所在的绕组层与初级绕组51所在的至少一个绕组层之间不存在其他绕组层。
需要说明的是，由于平面变压器40的截面是对称的，图4展示了该PCB绕组板42的半个截面的示意图。作为示例，该截面位于z轴和r轴形成的zr平面，其中z轴垂直位于PCB绕组板的表面所在的平面(比如还可以称为第一平面)，r轴为垂直与z轴且指向PCB绕组板中心的方向。也就是说，zr平面与第一平面垂直。类似地，下文中的图5至图13展示了平面变压器的截面图示意图。
一些可选的实施例，初级绕组51、次级绕组52和屏蔽绕组53均位于上述截面内，且该初级绕组51沿z轴在该第一平面上的投影和该次级绕组52沿z轴在第一平面上的投影均位于该屏蔽绕组53沿z轴在第一平面上的投影内。这样，屏蔽绕组能够完全屏蔽初级绕组51与次级绕组52之间的电场耦合。
一些可选的实施例，初级绕组51、次级绕组52和屏蔽绕组53均位于上述截面内，且该初级绕组51沿z轴在该第一平面上的投影或者该次级绕组52沿z轴在第一平面上的投影位于该屏蔽绕组53沿z轴在第一平面上的投影内。这样在工艺上容易实现，并且对于初级绕组51与次级绕组52之间的电场耦合，屏蔽绕组能够实现较好的屏蔽效果。
图5和图6分别示出了PCB绕组板中的绕组线圈的一个示例。其中，在图5以及图6所示的平面变压器中，所述屏蔽绕组的第一端头连接电源转换电路的初级电路的电位静点，例如初级工作地网络的点。需要说明的是，本申请实施例中，相同的附图标记表示相同或相似的含义，这里不再赘述。
作为一个示例，如图5所示，补偿绕组54与次级绕组52相邻，屏蔽绕组53可以与初级绕组51相邻，或者屏蔽绕组53与初级绕组51和次级绕组52均相邻。例如，图5中所示的平面变压器包括两个屏蔽绕组，其中一个与初级绕组51和次级绕组52均相邻，其中一个与初级绕组51和补偿绕组相邻。该补偿绕组54的第一端头连接该初级电路的电位静点，其中该补偿绕组的第一端头开始为该补偿绕组的第1匝线圈。可选的，该补偿绕组54的第二端头可以悬空，其中，第二端头对应补偿绕组54的最后1匝(即第N匝)线圈的一端。
作为另一个示例，如图6所示，补偿绕组54与上述初级绕组51相邻，屏蔽绕组53可以与次级绕组52相邻，或者屏蔽绕组53与初级绕组51和次级绕组52均相邻。例如，图6中所示的平面变压器包括两个屏蔽绕组，其中一个与初级绕组51和次级绕组52均相邻，其中一个与次级绕组52和补偿绕组54相邻。该补偿绕组54的第一端头连接该次级电路的电位静点，其中该补偿绕组的第一端头开始为该补偿绕组的第1匝线圈。可选的，该补偿绕组54的第二端头可以悬空，其中，第二端头对应补偿绕组54的最后1匝(即第N匝)线圈的一端。
需要说明的是，当屏蔽绕组与初级绕组和次级绕组相邻时，屏蔽绕组可以屏蔽初级绕组直接耦合到次级绕组的噪声电流。当屏蔽绕组与补偿绕组相邻时，屏蔽绕组能够屏蔽初级绕组通过补偿绕组的匝间间隙耦合到次级绕组的噪声电流。
因此，当本申请实施例将初级绕组设置在次级绕组的两侧，或者将次级绕组设置在初级绕组的两侧时，可以分别在初级绕组和次级绕组之间均设置屏蔽绕组，来屏蔽初级绕组对次级绕组的电场耦合。因此，本申请实施例中，屏蔽绕组的个数可以为一个，两个，或者多个，本申请实施例对此不作限定。
在一些可选的实施例中，补偿绕组54的个数可以为至少一个(例如一个、两个或多个)，本申请实施例对此不作限定。当补偿绕组的个数为大于或等于两个时，该至少两个补偿绕组的连接方式相似。
一些可选的实施例，初级绕组51和次级绕组52的相对位置可以包括以下三种。
第一种：可以将初级绕组51设置在次级绕组52的两侧，即将初级绕组51中的一部分初级绕组层设置在次级绕组52的一侧，将另一部分初级绕组层设置在次级绕组52的另一侧，构成类似于“三明治”的夹层结构。这样，可以降低绕组的高频涡流损耗和漏感。
第二种：可以将次级绕组52设置在初级绕组51的两侧。
第三种：初级绕组51包括的全部初级绕组层设置于次级绕组52的全部绕组层的一侧，比如上侧，或者下侧。
需要说明的是，在上述第一种或第二种情况下，初级绕组51和次级绕组52存在两处相邻的位置，对应的，屏蔽绕组53可以包括两个屏蔽绕组层，并分别设置于相邻的初级绕组层和次级绕组层之间。在上述第三种情况下，屏蔽绕组53可以包括一个屏蔽绕组层。
图7至图11示出了本申请实施例一些可能的绕组线圈的示例。作为示例，图5、图6以及图7为上述第一种位置的一个示例，图8为上述第二种位置的一个示例，图9至图11为上述第三种位置的一个示例。
应理解，图7至图11示出了绕组线圈仅是示例，本申请实施例并不限于此。另外，图7至图11中与图5或图6中相同的附图标记表示相同或相似的含义，为了简洁，此处不再赘述。
如图7至图11所示，初级绕组51可以包括辅助绕组511和初级功率绕组512。在一些可选的实施例中，如图8所示，次级绕组52可以包括辅助绕组511和次级功率绕组522。
如图7所示的平面变压器，其初级绕组51设置在次级绕组52的两侧。可选的，该补偿绕组54的第一端头连接电源转换电路的初级电路的电位静点，补偿绕组54与次级绕组52相邻。示例性的，在该平面变压器的PCB绕组板的第一层以及最后一层分别为辅助绕组层，但本申请实施例并不限于此。
如图8所示的平面变压器，其次级绕组52设置在初级绕组51的两侧。可选的，该补偿绕组54的第一端头连接电源转换电路的初级电路的电位静点，补偿绕组54与次级绕组52相邻。示例性的，初级功率绕组的线圈可以与辅助绕组的线圈设置于同一层，次级功率绕组的线圈可以与辅助绕组的线圈设置于同一层，但本申请实施例并不限于此。
如图9所示的平面变压器，其初级绕组51包括的全部初级绕组层设置于次级绕组52的全部绕组层的一侧，比如下侧。并且，该补偿绕组54的第一端头连接电源转换电路的初级电路的电位静点，补偿绕组54与次级绕组52相邻。示例性的，在该平面变压器的PCB绕组板的最后一层(比如最下面一层)为辅助绕组层，但本申请实施例并不限于此。
与图9所示的平面变压器所不同的是，图10所示的补偿绕组54的第一端头连接电源转换电路的次级电路的电位静点，补偿绕组54与初级绕组51相邻。
另外，图9所示的平面变压器中的补偿绕组54设置于与次级绕组52相邻，并且靠近初级绕组51的一侧。与图9所示的平面变压器所不同的是，图11所示的平面变压器中的补偿绕组54设置于与次级绕组52相邻，并且远离初级绕组51的一侧。
具体的，图7至图11中各个绕组的连接方式可以参考图4至图6中的描述，为了简洁，这里不再赘述。
一些可选的实施例，补偿绕组54与第一绕组中的第一绕组层相邻，其中，所述第一绕组为与所述补偿绕组相邻的初级绕组，或与所述补偿绕组相邻的次级绕组。补偿绕组54的匝数与第一绕组层相关，即与与该补偿绕组54相邻的初级绕组层或次级绕组层相关。示例性的，该第一绕组层上设置有所述第一绕组的第Ns匝至第Ns+B-1匝线圈，其中，N满足如下条件：
N＝Nb*C，Nb＝2×Ns+B-2，
其中，Nb匝线圈产生的感应电压与所述第一绕组产生的感应电压相等，C为大于0的实数，Nb、Ns、B为正数。
在实际应用中，由于绕组的特征和原理，线圈的匝数N、Nb、Ns或B可以是整数，也可以不是整数，例如线圈的匝数可以为3匝，1.5匝，或者2.4匝，但本申请实施例并不限于此。
下面，将结合图12和图13，以第一绕组层为次级绕组层为例，描述本申请实施例中确定补偿绕组的匝数N的一个示例。应理解，图12和图13仅作为示例，但本申请实施例并不限于此。
在变压器工作时，补偿绕组54的匝数与Nb相关。其中，当补偿绕组54包括Nb匝线圈时，该Nb匝线圈产生的感应电压的平均值与该次级绕组产生的感应电压的平均值相等。
本申请实施例中，Nb的取值主要取决于与其相邻的次级绕组52上的电压。
图12示出了补偿绕组54与次级绕组相邻的情况下，次级绕组52和补偿绕组54的一个示例。如图12所示，次级绕组52包括4匝线圈以及两个端头。其中，连接次级电路的电路静点的端头为第一端头，连接次级整流管的端头为第二端头。我们定义从第一端头开始的线圈为第1匝线圈，依次类推，后面的分别为第2匝线圈、第3匝线圈和第4圈线圈。
本申请实施例中，还定义紧邻补偿绕组54的次级绕组52的匝数为第N x匝。示例性的，在图13中，补偿绕组54紧邻次级绕组52中的第2匝线圈设置，即此时N x＝2。
用于平衡次级绕组产生的感应电压的补偿绕组的匝数的理论值为Nb。一些实施例中，Nb可以根据如下公式确定：
Nb＝2*((N x+N x-1)/2)＝2(N x-0.5)＝2N x-1       (1)
作为示例，当Nx＝2时，Nb＝3。
图13示出了次级绕组52和补偿绕组54的另一个示例。如图13所示，次级绕组52包括N x+n匝线圈以及两个端头。其中，连接次级电路的电路静点的端头为第一端，连接次级整流管的端头为第二端。我们定义从第一端头开始的线圈为第1匝线圈，依次类推，后面的分别为第2匝线圈，至第N x+n匝线圈。
可选的，紧邻补偿绕组54的初级绕组层中设计的并非可以仅包含有1匝线圈，还可以包括B匝线圈。作为示例，B可以为大于1的实数。示例性的，在图13中，补偿绕组 54紧邻次级绕组52中的第N x匝至N x+B-1匝线圈设置。
用于平衡次级绕组产生的感应电压的补偿绕组的匝数的理论值为Nb。一些实施例中，Nb可以根据如下公式确定：
Nb＝2*((N x+B-1+(N x-1))/2)＝2(N x+B/2-1)＝2N x+B-2        (2)
需要说明的是，在实际工程设计中，受到PCB绕组绕线通道的空间限制，绕组的匝数受到一定的限制。因此，临近补偿绕组可以优先布置次级绕组中较小次序匝数的线圈，这样能够进一步减小Nb值的大小。
一些实施例中，C可以为大于0的实数。也就是说，N与Nb可以相等，N也可以大于Nb，或者小于Nb，本申请实施例对此不作限定。
一些可选的实施例，屏蔽绕组53的绕向与补偿绕组54的绕向相同，但本申请实施例并不限于此。
可选的，次级电路中包括次级整流管和次级滤波器，当次级整流管连接次级滤波电容的负极时，该补偿绕组54的第一端头和所述初级绕组51的第一端头互为异名端。此时，N可以大于或等于Nb。
一种可能的情况，当初级绕组51包括初级功率绕组时，该初级功率绕组的第一端连接电源转换电路的初级电路的电位静点，该补偿绕组54的第一端头与该初级功率绕组的第一端头为异名端。
图14示出了本申请实施例的电源转换电路中的共模噪声路径的一个示意图。如图14所示，初级绕组51的第一端头可以与初级滤波电容212连接，第二端头与初级开关管211连接，初级绕组51的电压跳变可以指初级开关管211在高频导通或关断时产生的跳变电压Vp。次级绕组52的第一端头可以与次级滤波电容222连接，第二端头与次级开关管221连接，次级绕组52的电压跳变可以指次级开关管221在高频导通或关断时产生的跳变电压Vs。其中，次级整流管221连接次级滤波电容222的负极。另外，屏蔽绕组53的第一端头可以与初级滤波电容212连接，第二端头悬空，补偿绕组54的第一端头可以与初级滤波电容212连接，第二端头悬空。
图14示出了当平面变压器不包括屏蔽绕组时基于反激变换器的可能的共模噪声路径，其一为初级电路的跳变电压Vp耦合到次级绕组的流向地的噪声电流+Ips，其二为次级电路中的跳变电压Vs产生的流向地的噪声电流+Isp，其三为补偿绕组产生流向初级绕组的感应电流-Id，其四是反激变换器系统中的其他噪声路径产生的流向地的噪声电流，例如为跳变电压Vp直接通过空间耦合电容Cpe耦合到LISN的+Id1。
如图15所示，当平面变压器包括补偿绕组，而不包括屏蔽绕组时，噪声电流Ips可以包括初级绕组的电位跳变Vp还可以通过补偿绕组匝间间隙耦合到次级绕组形成噪声电流，或者初级绕组的电位跳变Vp直接耦合到次级绕组形成的噪声电流。当平面变压器包括补偿绕组和屏蔽绕组时，屏蔽绕组能够减小甚至消除初级电路中的跳变电压Vp耦合到次级绕组的流向地的噪声电流。
因此，如图14所示，对于本申请实施例中的平面变压器包括了补偿绕组和屏蔽绕组的情况，此时补偿绕组至少需要抵消噪声电流(Isp+Id1)，因此补偿绕组需要抵消的噪声电流大于次级绕组产生的共模噪声，因此可以上述线圈匝数Nb进行正补偿，以进一步获得补偿绕组54的线圈匝数N。
作为示例，N可以满足如下条件：
N＝Nb*C1          (3)
其中，C1为大于1的实数。
一些可选的实施例，如图14所示，当平面变压器设置有屏蔽绕组时，如果实现Id＝Isp(假设屏蔽绕组能够完全消除Ips)，则能实现变压器本身的共模噪声的抵消。由于屏蔽绕组能够减小甚至消除初级电路中的跳变电压Vp耦合到次级绕组的流向地的噪声电流Isp，因此，通过设置屏蔽绕组可以减小C1的取值，即减小补偿绕组的匝数。
进一步的，当从整个反激变换器系统来看，如果要实现系统的共模噪声最小，需要满足Isp+Id1-Id＝0，即除了实现变压器本身的共模噪声的抵消之外，还需要考虑到对Id1的抵消。因此，为了实现反激变换器系统的共模噪声的抵消，C1可以根据所述初级绕组的电位跳变通过空间耦合电容耦合到线路阻抗稳定网络LISN的噪声电流来确定。
可选的，C1还可以根据PCB的制程容差来确定。其中，制程容差可以包括层间介质厚度公差、补偿绕组线宽公差、PCB板材介电常数公差等中的至少一种。
作为示例，在实现变压器本身的共模噪声的抵消时，考虑到屏蔽绕组，和/或，PCB的制程容差时，C1可以设置为1.3～1.8。作为示例，修正后的N-correction可以如下公式(4)所示：
N-correction＝[(Nb*1.3),(Nb*1.8)]      (4)
对应的，将公式(1)代入公式(4)，可以得到修正后的N-correction的取值如下：
N-correction＝[2.6(N x-0.5),3.6(N x-0.5)]       (5)
作为示例，当N x取值为2时，N-correction＝[3.9,5.4]。
对应的，将公式(2)代入公式(4)，可以得到修正后的N-correction的取值如下：
N-correction＝[2.6(N x+B/2-1),3.6(N x+B/2-1)]       (6)
作为示例，当除了实现变压器本身的共模噪声的抵消之外，还需要考虑到对Id1的抵消时，当考虑到初级功率绕组的电位跳变通过空间耦合电容耦合到线路阻抗稳定网络LISN形成噪声电流时，由于空间耦合电容Cpe的不确定性，C1可以在1.3～1.8的基础上进一步补偿为120％，即[1.3*1.2～1.8*1.2]，即1.56～2.16。作为示例，修正后的N-correction可以如下公式(7)所示：
N-correction＝[(Nb*1.56),(Nb*2.16)]      (7)
对应的，将公式(1)代入公式(7)，可以得到修正后的N-correction的取值如下：
N-correction＝[3.12(N x-0.5),4.32(N x-0.5)]      (8)
作为示例，当N x取值为2时，N-correction＝[4.68,6.48]。
对应的，将公式(2)代入公式(7)，修正后的N-correction的取值如下：
N-correction＝[3.12(N x+B/2-1),4.32(N x+B/2-1)]      (9)
可选的，次级电路中包括次级整流管和次级滤波电容，当次级整流管连接次级滤波电容的正极时，所述补偿绕组54的第一端头和所述初级绕组51的第一端头互为同名端。此时，N可以小于或等于Nb。
一种可能的情况，当初级绕组51包括初级功率绕组，该初级功率绕组的第一端头连接电源转换电路的初级电路的电位静点，该补偿绕组54的第一端头与该初级功率绕组的第一端为同名端。
图16示出了本申请实施例的电源转换电路中的共模噪声路径的一个示意图。如图16所示，初级绕组51的第一端头可以与初级滤波电容212连接，第二端头与初级开关管211连接，初级绕组51的电压跳变可以指初级开关管211在高频导通或关断时产生的跳变电压Vp。次级绕组52的第一端头可以与次级滤波电容222连接，第二端头与次级开关管221连接，次级绕组52的电压跳变可以指次级开关管221在高频导通或关断时产生的跳变电压Vs。其中，次级整流管221连接次级滤波电容222的正极。另外，屏蔽绕组53的第一端头可以与初级滤波电容212连接，第二端头悬空，补偿绕组54的第一端头可以与初级滤波电容212连接，第二端头悬空。
图16示出了当平面变压器不包括屏蔽绕组时基于反激变换器的可能的共模噪声路径，其一为初级电路的跳变电压Vp耦合到次级绕组的流向地的噪声电流+Idps，其二为次级电路中的跳变电压Vs产生的流向初级绕组的噪声电流-Isp，其三为补偿绕组产生流向次级绕组的感应电流+Id，其四是反激变换器系统中的其他噪声路径产生的流向地的噪声电流，例如为跳变电压Vp直接通过空间耦合电容Cpe耦合到LISN的+Id1。
当平面变压器包括补偿绕组，而不包括屏蔽绕组时，噪声电流+Ips可以包括初级电路的跳变电压Vp通过补偿绕组匝间间隙耦合到次级绕组形成噪声电流，或者初级绕组的电位跳变Vp直接耦合到次级绕组形成的噪声电流。当平面变压器包括补偿绕组和屏蔽绕组时，屏蔽绕组能够减小甚至消除初级电路中的跳变电压Vp耦合到次级绕组的流向地的噪声电流。
因此，如图16所示，对于本申请实施例中的平面变压器包括了补偿绕组和屏蔽绕组的情况，此时补偿绕组至少需要抵消噪声电流(Isp-Id1)，因此补偿绕组需要抵消的噪声电流小于次级绕组产生的共模噪声，因此可以上述线圈匝数Nb进行负补偿，以进一步获得补偿绕组54的线圈匝数N。
作为示例，N可以满足如下条件：
N＝Nb*C2         (10)
其中，C2为取值范围为(0，1]的实数。
基于与上述实施例相似的原理，由于屏蔽绕组能够减小甚至消除初级电路中的跳变电压Vp耦合到次级绕组的流向地的噪声电流Id1，因此，通过设置屏蔽绕组可以减小C2的取值，即减小补偿绕组的匝数。进一步的，当需要考虑到对Id2的抵消时，C2可以根据所述初级绕组的电位跳变通过空间耦合电容耦合到线路阻抗稳定网络LISN的噪声电流来确定。
可选的，C2还可以根据PCB的制程容差来确定。其中，制程容差可以包括层间介质厚度公差、补偿绕组线宽公差、PCB板材介电常数公差等中的至少一种。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (14)

  1. 一种平面变压器，其特征在于，包括磁芯和印刷电路板PCB绕组板，其中所述PCB绕组板包括：
    初级绕组，所述初级绕组的第一端头连接电源转换电路的初级电路的电位静点，其中，从所述初级绕组的第一端头开始为所述初级绕组的第1匝线圈；
    次级绕组，所述次级绕组的第一端头连接所述电源转换电路的次级电路的电位静点，其中，从所述次级绕组的第一端头开始为所述次级绕组的第1匝线圈；
    屏蔽绕组，设置于所述初级绕组和所述次级绕组之间，用于屏蔽所述初级绕组与所述次级绕组之间的电场耦合；
    补偿绕组，与所述初级绕组相邻，或与所述次级绕组相邻，所述补偿绕组包括N匝线圈，N为大于1的正数。
  2. 根据权利要求1所述的平面变压器，其特征在于，所述屏蔽绕组与所述初级绕组相邻，或与所述次级绕组相邻。
  3. 根据权利要求1或2所述的平面变压器，其特征在于，所述初级绕组沿z轴在第一平面上的投影和/或所述次级绕组沿所述z轴在所述第一平面上的投影位于所述屏蔽绕组沿所述z轴在所述第一平面上的投影内，所述第一平面为所述PCB绕组板的表面所在的平面，所述z轴垂直于所述第一平面。
  4. 根据权利要求1-3任一项所述的平面变压器，其特征在于，所述补偿绕组与所述次级绕组相邻，所述补偿绕组的第一端头连接所述初级电路的电位静点。
  5. 根据权利要求1-3任一项所述的平面变压器，其特征在于，所述补偿绕组与所述初级绕组相邻，所述补偿绕组的第一端头连接所述次级电路的电位静点。
  6. 根据权利要求4或5所述的平面变压器，其特征在于，所述次级电路中包括次级整流管和次级滤波电容，当所述次级整流管连接所述次级滤波电容的负极时，所述补偿绕组的第一端头和所述初级绕组的第一端头互为异名端。
  7. 根据权利要求4或5所述的平面变压器，其特征在于，所述次级电路中包括次级整流管和次级滤波电容，当所述次级整流管连接所述次级滤波电容的正极时，所述补偿绕组的第一端头和所述初级绕组的第一端头互为同名端。
  8. 根据权利要求1-7任一项所述的平面变压器，其特征在于，所述补偿绕组与第一绕组中的第一绕组层相邻，其中，所述第一绕组为与所述补偿绕组相邻的初级绕组，或与所述补偿绕组相邻的次级绕组，所述第一绕组层上设置有所述第一绕组的第Ns匝至第Ns+B-1匝线圈，其中，N满足如下条件：
    N＝Nb*C，Nb＝2×Ns+B-2，
    其中，Nb匝线圈产生的感应电压与所述第一绕组产生的感应电压相等，C为大于0的实数，Nb、Ns、B为正数。
  9. 根据权利要求8所述的平面变压器，其特征在于，C的取值范围为[1.56，2.16]或(0,1]。
  10. 根据权利要求1-9任一项所述的平面变压器，其特征在于，所述补偿绕组的第二 端头悬空。
  11. 根据权利要求1-10任一项所述的平面变压器，其特征在于，所述初级电路的电位静点包括所述初级电路中连接母线电容正极或初级工作地网络的点，所述次级电路的电位静点包括所述次级电路中连接次级输出滤波电容的正极或次级工作地网络的点，其中，所述电位静点在电路工作过程中电压无跳变。
  12. 根据权利要求1-11任一项所述的平面变压器，其特征在于，所述屏蔽绕组的第一端头连接所述初级电路的电位静点或者所述次级绕组的电位静点，且所述屏蔽绕组的第二端头悬空。
  13. 一种电源转换电路，其特征在于，包括：如权利要求1至12中任一项所述的平面变压器、初级电路以及次级电路，所述平面变压器设置在所述初级电路和所述次级电路之间。
  14. 一种适配器，其特征在于，包括如权利要求13所述的电源转换电路。
PCT/CN2020/083477 2019-06-14 2020-04-07 平面变压器、电源转换电路以及适配器 WO2020248672A1 (zh)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113436865A (zh) * 2021-06-24 2021-09-24 珠海格力电器股份有限公司 一种变压器及开关电源电路

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110310815A (zh) * 2019-06-14 2019-10-08 华为技术有限公司 平面变压器、电源转换电路以及适配器
CN110911126A (zh) * 2019-11-08 2020-03-24 深圳市航嘉驰源电气股份有限公司 一种平面变压器及电源转换器
CN111312489B (zh) * 2020-02-20 2021-08-17 连云港杰瑞电子有限公司 一种变压器绕组排列方法及其位移电流数值分析方法
CN111312496B (zh) * 2020-03-20 2023-05-09 惠州三盛源电子有限公司 可调节共模的变压器及其共模调节方法
CN114068158B (zh) * 2020-07-30 2024-06-18 华为技术有限公司 平面变压器、电源转换电路以及电源适配器
CN114496523A (zh) * 2020-10-28 2022-05-13 华为技术有限公司 平面变压器、电源转换电路及适配器
CN112821787A (zh) * 2021-01-04 2021-05-18 格力电器（武汉）有限公司 开关电源变压器、开关电源电路和开关电源
CN116153632A (zh) * 2021-11-22 2023-05-23 广州视源电子科技股份有限公司 电压变换方法、电子设备、平面变压器及其绕组结构
CN114694934A (zh) * 2022-03-09 2022-07-01 深圳亿思腾达集成股份有限公司 一种集成共模电感功能的pcb平面变压器及其设计方法
CN115359998B (zh) * 2022-08-30 2024-02-27 苏州力生美半导体有限公司 带补偿电容的平面变压器
CN116418219A (zh) * 2023-01-13 2023-07-11 哈尔滨工业大学（深圳） 一种低共模电磁噪声的比例平衡结构的隔离开关电源设计
CN116629040B (zh) * 2023-03-31 2024-04-26 东莞市奥海科技股份有限公司 平面变压器优化设计方法
CN117709133B (zh) * 2024-02-05 2024-04-19 成都兴仁科技有限公司 一种多路输出反激平面电感的设计方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202013796U (zh) * 2010-12-31 2011-10-19 崧顺电子（深圳）有限公司 一种无y电容的变压器
JP2015133440A (ja) * 2014-01-15 2015-07-23 カルソニックカンセイ株式会社 プレーナ型トランス
CN108122667A (zh) * 2017-12-05 2018-06-05 华为数字技术（苏州）有限公司 变压器及电源装置
CN108364768A (zh) * 2017-11-10 2018-08-03 华为技术有限公司 平面变压器、电源转换电路以及适配器
CN110310815A (zh) * 2019-06-14 2019-10-08 华为技术有限公司 平面变压器、电源转换电路以及适配器

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04152609A (ja) * 1990-10-17 1992-05-26 Mitsubishi Electric Corp 変成器回路装置
CN105655113B (zh) * 2014-11-12 2018-04-17 台达电子工业股份有限公司 Pcb平面变压器及使用这种变压器的变换器
WO2019096892A1 (en) * 2017-11-15 2019-05-23 Salcomp Oyj A planar transformer and a method for reducing common-mode noise in a planar transformer
CN107993814A (zh) * 2017-11-15 2018-05-04 赛尔康技术（深圳）有限公司 一种补偿电磁干扰的平面变压器
EP3576113B1 (en) * 2018-05-31 2021-01-06 Salcomp Oyj A planar transformer and a method for shielding windings in a planar transformer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202013796U (zh) * 2010-12-31 2011-10-19 崧顺电子（深圳）有限公司 一种无y电容的变压器
JP2015133440A (ja) * 2014-01-15 2015-07-23 カルソニックカンセイ株式会社 プレーナ型トランス
CN108364768A (zh) * 2017-11-10 2018-08-03 华为技术有限公司 平面变压器、电源转换电路以及适配器
CN108122667A (zh) * 2017-12-05 2018-06-05 华为数字技术（苏州）有限公司 变压器及电源装置
CN110310815A (zh) * 2019-06-14 2019-10-08 华为技术有限公司 平面变压器、电源转换电路以及适配器

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3979277A4

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113436865A (zh) * 2021-06-24 2021-09-24 珠海格力电器股份有限公司 一种变压器及开关电源电路

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