CN216599430U

CN216599430U - Switching power supply

Info

Publication number: CN216599430U
Application number: CN202122472416.1U
Authority: CN
Inventors: 任杰; 赵为阳; 方俊翔
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2021-10-13
Filing date: 2021-10-13
Publication date: 2022-05-24
Anticipated expiration: 2031-10-13

Abstract

The application provides a switching power supply, need not set up extra filtering device, realizes the suppression to common mode interference on the basis that does not increase switch size and cost. The switching power supply comprises a first conversion module and a second conversion module. The input end of the first conversion module is connected with an alternating current power supply, the output end of the first conversion module is connected with the input end of the second conversion module, and the output end of the second conversion module is connected with a load. The second conversion module comprises a first winding, a magnetic core, a switch tube, a second winding and a conductor, the first inductor comprises the first winding and the magnetic core, the first winding and the second winding are wound on the magnetic core, the first end of the second winding is connected with the grounding end or the output end of the first conversion module, and the second end of the second winding is connected with the conductor.

Description

Switching power supply

Technical Field

The application relates to the technical field of energy, in particular to a switching power supply in the technical field of energy.

Background

With the rapid development of semiconductor technology, attention is increasingly paid to and paid to electromagnetic compatibility (EMC) of switching power supplies. Electromagnetic compatibility refers to the ability of a system including a switching power supply to operate properly in its electromagnetic environment without creating unacceptable electromagnetic interference to any device in the electromagnetic environment.

Since the switching tube of the switching power supply is in a high-speed switching state with a large voltage conversion rate and a large current conversion rate, the switching power supply may generate Common Mode Interference (CMI) during operation, which may affect normal operations of other devices in a system in which the switching power supply is located.

In the related art, a common-mode inductor is usually arranged at an alternating-current input end of a switching power supply, and common-mode interference is suppressed through a filtering function of the common-mode inductor. However, the provision of common mode inductance tends to increase the size and cost of the switching power supply.

Disclosure of Invention

The application provides a switching power supply, need not set up extra filter, realizes the suppression to common mode interference on the basis that does not increase switch size and cost.

The application provides a switching power supply which can comprise a first conversion module and a second conversion module.

The first conversion module may include an ac input terminal and a first dc output terminal, and the second conversion module may include a dc input terminal and a second dc output terminal.

The ac input may be adapted for connection to an ac power source, the first dc output may be adapted for connection to a dc input, and the second dc output may be adapted for connection to a load.

Optionally, the second conversion module may include a first inductor and a switching tube connected to the first inductor. The first inductor may include a first winding and a magnetic core, and the first winding may be wound around the magnetic core.

Further, the second transformation module may further include a second winding and a conductor, the second winding is also wound around the magnetic core, and the second winding and the magnetic core may form a second inductor. The first end of the second winding may be connected to ground or may be connected to a first dc output terminal and the second end of the second winding may be connected to a conductor.

In one example, the conductor may be a magnetic core. Of course, the conductor may also be other conductive components in the switching power supply besides the magnetic core, which is not limited in this application.

In another example, the switching tube may include a power device. The power device may employ a metal-oxide-semiconductor field-effect transistor (MOSFET), or an Insulated Gate Bipolar Transistor (IGBT). Of course, the switch tube may also include other types of power devices, which is not limited in this application.

Further, the switching tube may further include a diode connected in anti-parallel with the power device. The power device and the diode may then constitute a switching tube.

Optionally, the first transforming module may include a second diode, a third diode, a fourth diode, a fifth diode, and a second capacitor.

The anode of the second diode and the cathode of the third diode can be connected with a first alternating current end of an alternating current power supply, the cathode of the fourth diode and the anode of the fifth diode can be connected with a second alternating current end of the alternating current power supply, the cathode of the second diode, the cathode of the fifth diode and the anode of the second capacitor can be connected with a direct current input end, and the cathode of the third diode, the cathode of the fourth diode and the cathode of the second capacitor can be connected with a grounding end.

In one possible implementation, the second transformation module may further include a first diode and a first capacitor.

The anode of the first diode and the first end of the switch tube can be connected with the first end of the first winding, the cathode of the first diode can be connected with the second direct-current output end, the second end of the switch tube can be connected with the grounding end, the second end of the first winding can be connected with the direct-current input end, the positive end of the first capacitor can be connected with the second direct-current output end, and the negative end of the first capacitor can be connected with the grounding end.

It can be seen that, a boost circuit (which may have a boosting function) is used in the switching power supply formed by the first conversion module and the second conversion module provided in the foregoing implementation manner, the first conversion module may convert (i.e., rectify) the ac power output by the ac power supply into dc power, and the second conversion module may convert (i.e., invert) the dc power output by the first conversion module into ac power and provide the ac power to a load (i.e., supply power to the load).

In another possible implementation manner, the second conversion module further includes a first diode and a first capacitor.

The anode of the first diode and the first end of the switch tube can be connected with the first end of the first winding, the cathode of the first diode can be connected with the direct current input end, the second end of the switch tube can be connected with the grounding end, and the anode end of the first capacitor, the cathode end of the first capacitor and the second end of the first winding can be connected with the second direct current output end.

It can be seen that the switching power supply formed by the first conversion module and the second conversion module provided in the foregoing implementation manner adopts a buck circuit (which may have a voltage reduction function), the first conversion module may convert (i.e., rectify) the ac power output by the ac power supply into dc power, and the second conversion module may convert (i.e., invert) the dc power output by the first conversion module into ac power and provide the ac power to a load (i.e., supply power to the load).

In yet another possible implementation, the second transformation module may further include a first diode and a first capacitor.

The anode of the first diode and the first end of the switch tube can be connected with the first end of the first winding, the cathode of the first diode can be connected with the second direct-current output end, the second end of the switch tube can be connected with the grounding end, the second end of the first winding can be connected with the direct-current input end, and the positive end and the negative end of the first capacitor can be connected with the second direct-current output end.

It can be seen that the switching power supply formed by the first conversion module and the second conversion module provided in the foregoing implementation manner adopts a buck-boost circuit (which may have a voltage reduction function, a voltage boosting function, or a power transmission function), the first conversion module may convert (i.e., rectify) the ac power output by the ac power supply into dc power, and the second conversion module may convert (i.e., invert) the dc power output by the first conversion module into ac power and provide the ac power to a load (i.e., supply power to the load).

In yet another possible implementation, the second transformation module may further include a first diode, a first capacitor, and a third winding.

The first end of the switching tube can be connected with the first end of the first winding, the second end of the switching tube can be connected with the ground terminal, and the second end of the first winding can be connected with the direct-current input end;

the third winding can be wound on the magnetic core, the first end of the third winding can be connected with the anode of the first diode, the second end of the third winding can be connected with the cathode end of the first capacitor, and the cathode of the first diode and the anode end of the first capacitor can be connected with the second direct current output end.

The switching power supply formed by the first conversion module and the second conversion module provided by the above implementation manner adopts a flyback circuit (which may have a voltage reduction function, a voltage boosting function or a power transmission function), the first conversion module may convert (i.e., rectify) the alternating current output by the alternating current power supply into direct current, and the second conversion module may convert (i.e., invert) the direct current output by the first conversion module into alternating current and provide the alternating current to a load (i.e., supply power to the load).

In an example, the first end of the first winding and the second end of the third winding may be opposite-name ends. That is, the first end of the first winding and the first end of the third winding may be terminals of the same name.

In another example, the first end of the first winding and the second end of the second winding may be opposite-name ends. That is, the first end of the first winding and the first end of the second winding may be terminals of the same name.

In the above several possible implementations, a parasitic capacitance (denoted by Cp 1) exists between the first winding, to which the first inductor is connected to the connection node of the switching tube (which may be called node a), and the ground. The voltage at node A generates a common mode current (with I) across parasitic capacitance Cp1₁Representation). A parasitic capacitance (denoted by Cp 2) exists between the conductor to which the second inductance and the connection node of the conductor (which may be called node B) are connected and the ground. The voltage at node B generates a common mode current (with I) across parasitic capacitance Cp2₂Representation).

In conjunction with the synonym end relationship between the first winding and the second winding, it can be determined that the phase of the voltage at node B is opposite to the phase of the voltage at node a. Therefore, the common mode current I₂Direction of (D) and common mode current I₂In the opposite direction.

Due to common mode current I₂Direction of (D) and common mode current I₂Are opposite in direction and equal in amplitude, so that a common mode current I can pass₂Counteracting the common mode current I₁So to speak, the common mode current I₂And a common mode current I₁Mutual cancellation can be realized, and therefore common-mode interference of the switching power supply is suppressed from the source.

Optionally, the switching power supply provided by the present application may further include a filtering module.

The input end of the filtering module can be connected with an alternating current power supply, and the output end of the filtering module can be connected with an alternating current input end.

From the above connection relationship, it can be determined that:

the filtering module may be configured to: and filtering the alternating current output by the alternating current power supply and protecting the first conversion module.

Alternatively, the filter module may employ a filter capacitor, a filter inductor, or a circuit combining the filter capacitor and the filter inductor (which may be a complex filter circuit). Of course, the filtering module can also adopt other devices to filter the alternating current output by the alternating current power supply, and the structure of the filtering module is not limited in the application.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.

Fig. 1 is a schematic structural diagram of a switching power supply in an embodiment of the present application;

fig. 2 is a schematic diagram illustrating an operating principle of the switching power supply in the embodiment of the present application;

FIG. 3 is a schematic structural diagram of a switching power supply in an embodiment of the present application

FIG. 4 is a schematic structural diagram of a switching power supply in an embodiment of the present application

Fig. 5 is a schematic structural diagram of a switching power supply in the embodiment of the present application.

Detailed Description

To make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application, and it is obvious that the described embodiments are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first," "second," and the like in the description examples and claims of this application and in the drawings are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, nor order. Furthermore, the terms "comprises" and "comprising," as well as any variations thereof, are intended to cover a non-exclusive inclusion, such as a list of steps or elements. A method, system, article, or apparatus is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, system, article, or apparatus.

It should be understood that in the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" for describing an association relationship of associated objects, indicating that there may be three relationships, e.g., "a and/or B" may indicate: only A, only B and both A and B are present, wherein A and B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

With the rapid development of semiconductor technology, the electromagnetic compatibility of the switching power supply is increasingly paid attention and paid attention. Electromagnetic compatibility refers to the ability of a system including a switching power supply to operate properly in its electromagnetic environment without creating unacceptable electromagnetic interference to any device in the electromagnetic environment.

Because the switching tube of the switching power supply is in a high-speed switching state, which is accompanied by a large voltage conversion rate and a large current conversion rate, the switching power supply may generate common-mode interference during operation, which may affect the normal operation of other devices in the system in which the switching power supply is located.

In order to suppress common mode interference, the embodiment of the present application provides a switching power supply, as shown in fig. 1. The switching power supply 1 may include a conversion module 11 (i.e., a first conversion module) and a conversion module 12 (i.e., a second conversion module).

Among them, the conversion module 11 may include an ac input terminal (i.e., node G and node F in fig. 1) and a first dc output terminal (i.e., node H in fig. 1), and the conversion module 12 may include a dc input terminal (i.e., node J in fig. 1) and a second dc output terminal (i.e., node I in fig. 1).

Alternatively, the ac input terminal may be used for connection with the ac power source S, that is, the node G and the node F may be connected with the ac power source S. The first dc output may be for connection to a dc input, that is, node H may be connected to node J. The second dc output may be used for connection to a load L, i.e. node I may be connected to load L.

Referring to fig. 1, the transformation module 22 may include an inductor L1 (i.e., a first inductor) and a switching tube Q1 connected to the inductor L1, the inductor L1 includes a winding W (winding)1 (i.e., a first winding) and a Magnetic Core (MC), and the winding W1 is wound around the magnetic core MC.

Optionally, the switching tube Q1 may include a power device. The power device can adopt a metal-oxide semiconductor field effect transistor MOSFET or an insulated gate bipolar transistor IGBT. Of course, the switching tube Q1 may also include other types of power devices, which is not limited in this embodiment, and this embodiment is described by taking an N-channel enhancement type MOS tube (hereinafter referred to as MOS tube for short) as an example.

Further, the MOS transistor may be connected in anti-parallel with a diode (the diode may be called a parasitic diode). Thus, the MOS transistor and the diode may form the switching transistor Q1.

The transformation module 22 may further include a winding W2 (i.e., a second winding) and a conductor c (conductor), the winding W2 is wound around the magnetic core MC, and the winding W2 and the magnetic core MC may form an inductor L2 (i.e., a second inductor).

The first end of winding W2 may be connected to ground or node H (for example, the first end of winding W2 is connected to ground in fig. 1), and the second end of winding W2 is connected to conductor C. The node at which the first end of winding W2 is connected to ground is node E in fig. 1, and the node at which the second end of winding W2 is connected to conductor C is node B in fig. 1.

Alternatively, the conductor C may be a metal plate inside the switching power supply, or may be the core MC (that is, the second end of the winding W2 may be directly connected to the core MC without a separate conductor). Of course, the conductor C may also be another conductive component inside the switching power supply, which is not limited in this embodiment of the application.

In one possible implementation, as shown in fig. 1, the switching power supply 1 may further include a filtering module 13. The input of the filtering module 13 may be connected to the ac power source S, and the output of the filtering module 13 may be connected to the nodes G and F.

According to the connection relationship, it can be determined that the filtering module 13 can be used for filtering Alternating Current (AC) output by the AC power source S and protecting the transformation module 11.

Alternatively, the filter module 13 may employ a filter capacitor, a filter inductor, or a circuit combining the filter capacitor and the filter inductor (which may be a complex filter circuit). Certainly, the filtering module 13 may also adopt other devices to filter the alternating current output by the alternating current power supply S, and the structure of the filtering module 13 is not limited in this embodiment of the application.

In another possible implementation, the transformation module 11 may include a diode D2 (i.e., a second diode), a diode D3 (i.e., a third diode), a diode D4 (i.e., a fourth diode), a diode D5 (i.e., a fifth diode), and a capacitor C2 (i.e., a second capacitor).

Optionally, the anode of the diode D2 and the cathode of the diode D3 are both connected to a node G, the node G is connected to the first ac terminal of the ac power source S through the filtering module 13, the cathode of the diode D4 and the anode of the diode D5 are connected to a node F, and the node F is connected to the second ac terminal of the ac power source S through the filtering module 13. The cathode of the diode D2, the cathode of the diode D5, and the anode of the capacitor C2 are all connected to a node H, which may be connected to the second end of the winding W1 (i.e., the left end of the winding 1) in fig. 1 via a node J, and the cathode of the diode D3, the cathode of the diode D4, and the cathode of the capacitor C2 may be connected to the ground.

With continued reference to fig. 1, the transformation module 12 may further include a diode D1 (i.e., a first diode) and a capacitor C1 (i.e., a first capacitor).

The anode of the diode D1 and the drain (i.e., the first end) of the switching tube Q1 are both connected to the node a, and the first end of the winding W1 (i.e., the right end of the winding W1 in fig. 1, that is, the end close to the node a) is also connected to the node a, which is a node connecting the diode D1 and the winding W1. The cathode of the diode D1 and the positive terminal of the capacitor C1 may be connected to the node I, and the source (i.e., the second terminal) of the switching transistor Q1 and the negative terminal of the capacitor C1 may be connected to the ground. One end of the load L is connected with the node I, and the other end of the load L is connected with the grounding terminal.

Alternatively, the first end of the winding W1 (i.e., the end connected to the node a) and the second end of the winding W2 (i.e., the end connected to the node B) may be synonyms.

It can be seen that the switching power supply shown in fig. 1 adopts a boost circuit (which may have a boosting function), the conversion module 11 may convert (i.e., rectify) the ac power output by the ac power supply S into dc power, and the conversion module 12 may convert (i.e., invert) the dc power output by the conversion module 11 into ac power and provide the ac power to the load L (i.e., supply power to the load L).

A parasitic capacitance Cp1 as shown in fig. 2 exists between the devices connected by the node a in fig. 1 (i.e., the winding W1, the switching tube Q1 and the diode D1) and the ground. The voltage at node a will generate a current at parasitic capacitor Cp1, which will flow back to the ac power source S through the first ac terminal of the ac power source S and the second ac terminal of the ac power source S, and thus the current may be referred to as a common mode current (I may be used)₁Representation). When the switch power supply is subjected to an electromagnetic interference test, the common-mode current I₁The presence of (a) may result in large common mode interference (i.e. the common mode interference exceeds a preset interference threshold).

In the embodiment of the application, the common mode current I generated by the node A can be counteracted by arranging the winding W2₁Thereby realizing the suppression of common mode interference. Therefore, winding W2 may also be referred to as a cancellation winding. The detailed process of canceling the common mode current by the winding W2 according to the embodiment of the present application will be described below with reference to fig. 2.

Since a parasitic capacitance Cp2 exists between the device (i.e. the conductor C) connected to the node B in fig. 2 and the ground as shown in fig. 2, the voltage at the node B generates a common mode current (i.e. I can be used) on the parasitic capacitance Cp2₂Representation). The value of the parasitic capacitance Cp2 can be changed by adjusting the area of the conductor C, or the voltage amplitude of the winding W2 can be changed by adjusting the number of turns of the winding W2, so that the common mode current I can be adjusted₂Of the amplitude of the common-mode current I₂Amplitude of and common mode current I₁Are equal in magnitude.

Further, in conjunction with the synonym end relationship between winding W1 and winding W2, it can be determined that the phase of the voltage at node B is opposite to the phase of the voltage at node A. Therefore, the common mode current I₂Direction of (1)And a common mode current I₂In the opposite direction.

Due to common mode current I₂Direction of (D) and common mode current I₂Are opposite in direction and equal in amplitude, so that a common mode current I can pass₂Counteracting the common mode current I₁So to speak, the common mode current I₂And a common mode current I₁Mutual cancellation can be achieved. Thus, a common mode current I₂Which may be referred to as a counteracting current.

The switching power supply shown in fig. 1 according to the embodiment of the present application can pass the common mode current I₂Common mode current I₁And the common mode interference of the switching power supply is suppressed from the source.

In one possible implementation, as shown in fig. 3, the switching power supply 1 may also include a conversion module 11 (i.e., a first conversion module) and a conversion module 12 (i.e., a second conversion module).

Among them, the transformation module 11 may include an ac input terminal (i.e., node G and node F in fig. 3) and a first dc output terminal (i.e., node H in fig. 3), and the transformation module 12 may include a dc input terminal (i.e., node J in fig. 3) and a second dc output terminal (i.e., node I and node K in fig. 3).

Alternatively, the ac input terminal may be used for connection with the ac power source S, that is, the node G and the node F may be connected with the ac power source S. The first dc output may be for connection to a dc input, that is, node H may be connected to node J. The second dc output may be configured to be connected to a load L, i.e. node I and node K may be connected to load L.

Referring to fig. 3, the transformation module 22 may include an inductor L1 (i.e., a first inductor) and a switching tube Q1 connected to the inductor L1, the L1 inductor includes a winding W1 (i.e., a first winding) and a magnetic core MC, and a winding W1 is wound around the magnetic core MC.

Alternatively, the switching tube Q1 may comprise a metal-oxide semiconductor field effect transistor MOSFET, or an insulated gate bipolar transistor IGBT. Of course, the switching tube Q1 may also include other types of power devices, which is not limited in this embodiment, and this embodiment is described by taking an N-channel enhancement type MOS tube (hereinafter referred to as MOS tube for short) as an example.

The transformation module 22 may further include a winding W2 (i.e., a second winding) and a conductor C, the winding W2 is wound around a core MC, and the winding W2 and the core MC may form an inductance L2 (i.e., a second inductance).

The first end of winding W2 may be connected to ground or node H (in fig. 2, the first end of winding W2 is connected to ground for example), and the second end of winding W2 is connected to conductor C. The node at which the first end of winding W2 is connected to ground is node E in fig. 3, and the node at which the second end of winding W2 is connected to conductor C is node B in fig. 3.

In one possible implementation, as shown in fig. 3, the switching power supply 1 may further include a filtering module 13. The input of the filtering module 13 may be connected to the ac power source S, and the output of the filtering module 13 may be connected to the nodes G and F.

According to the connection relationship, it can be determined that the filtering module 13 can be used for filtering the alternating current output by the alternating current power source S and protecting the transformation module 11.

Alternatively, the filter module 13 may employ a filter capacitor, a filter inductor, or a circuit combining the filter capacitor and the filter inductor (which may be a complex filter circuit). Of course, the filtering module 13 may also use other devices to filter the ac power output by the ac power source S, and the structure of the filtering module 13 is not limited in this embodiment of the application.

In another possible implementation, referring to fig. 3, the transformation module 11 may include a diode D2 (i.e., a second diode), a diode D3 (i.e., a third diode), a diode D4 (i.e., a fourth diode), a diode D5 (i.e., a fifth diode), and a capacitor C2 (i.e., a second capacitor).

Optionally, the anode of the diode D2 and the cathode of the diode D3 are both connected to a node G, the node G is connected to the first ac terminal of the ac power source S through the filtering module 13, the cathode of the diode D4 and the anode of the diode D5 are connected to a node F, and the node F is connected to the second ac terminal of the ac power source S through the filtering module 13. The cathode of the diode D2, the cathode of the diode D5, and the anode of the capacitor C2 are all connected to a node H, which may be connected to a node J, and the cathode of the diode D3, the cathode of the diode D4, and the cathode of the capacitor C2 may be connected to ground.

With continued reference to fig. 3, the transformation module 12 may further include a diode D1 (i.e., a first diode) and a capacitor C1 (i.e., a first capacitor).

The anode of the diode D1 and the drain (i.e., the first end) of the switching tube Q1 are both connected to the node a, and the first end of the winding W1 (i.e., the left end of the winding W1 in fig. 3, i.e., the end close to the node a) is also connected to the node a. Node a is seen to be the node connecting diode D1 with winding W1. The cathode of the diode D1 may be connected to the node J, and the source (i.e., the second terminal) of the switch Q2 may be connected to the ground terminal. Node J is connected to node I, which may be connected to the positive terminal of capacitor C1, and the negative terminal of capacitor C1 and the second terminal of winding W1 (i.e., the right end of winding W1 in fig. 3) may be connected to node K. One end of the load L is connected with the node I, and the other end of the load L is connected with the node K.

It can be seen that the switching power supply shown in fig. 3 adopts a buck circuit (which may have a voltage reduction function), the conversion module 11 may convert (i.e., rectify) the ac power output by the ac power supply S into dc power, and the conversion module 12 may convert (i.e., invert) the dc power output by the conversion module 11 into ac power and provide the ac power to the load L (i.e., supply power to the load L).

The device connected by node A in FIG. 3 (i.e. winding W1, switching tube Q1 and diode D1) is connected to groundWith a parasitic capacitance Cp1 present therebetween. The voltage at the node A generates a current in the parasitic capacitor Cp1, which flows back to the AC power source S through the first AC terminal of the AC power source S and the second AC terminal of the AC power source S, and thus the current can be referred to as a common mode current I₁. When the switch power supply is subjected to an electromagnetic interference test, the common mode current I₁The presence of (a) may result in large common mode interference (i.e. the common mode interference exceeds a preset interference threshold).

In the embodiment of the application, the common mode current I generated by the node A can be counteracted by arranging the winding W2₁Thereby realizing the suppression of common mode interference. Therefore, winding W2 may also be referred to as a cancellation winding.

Node B generates a common mode current I at parasitic capacitance Cp2 due to parasitic capacitance Cp2 between the device to which node B is connected (i.e., conductor C) and ground₂. The value of the parasitic capacitance Cp2 can be changed by adjusting the area of the conductor C, or the voltage amplitude of the winding W2 can be changed by adjusting the number of turns of the winding W2, so that the common mode current I can be adjusted₂Of the amplitude of the common-mode current I₂Amplitude of and common mode current I₁Are equal in magnitude.

Further, in conjunction with the synonym end relationship between winding W1 and winding W2, it can be determined that the phase of the voltage at node B is opposite to the phase of the voltage at node A. Therefore, the common mode current I₂Direction of (D) and common mode current I₂In the opposite direction.

The switching power supply shown in fig. 3 according to the embodiment of the present application can pass the common mode current I₂Common mode current I₁And the common mode interference of the switching power supply is suppressed from the source.

In one possible implementation, as shown in fig. 4, the switching power supply 1 may also include a conversion module 11 (i.e., a first conversion module) and a conversion module 12 (i.e., a second conversion module).

Among them, the transformation module 11 may include an ac input terminal (i.e., node G and node F in fig. 4) and a first dc output terminal (i.e., node H in fig. 4), and the transformation module 12 may include a dc input terminal (i.e., node J in fig. 4) and a second dc output terminal (i.e., node I and node K in fig. 4).

Alternatively, the ac input terminal may be used for connection to the ac power source S, that is, the node G and the node F may be connected to the ac power source S. The first dc output may be for connection to a dc input, that is, node H may be connected to node J. The second dc output may be adapted to be connected to a load L, i.e. node I and node K may be connected to load L.

Referring to fig. 4, the transformation module 22 may include an inductor L1 (i.e., a first inductor) and a switching tube Q1 connected to the inductor L1, the L1 inductor includes a winding W1 (i.e., a first winding) and a magnetic core MC, and a winding W1 is wound around the magnetic core MC.

The first end of winding W2 may be connected to ground or node H (in fig. 4, the first end of winding W2 is connected to ground for example), and the second end of winding W2 is connected to conductor C. The node at which the first end of winding W2 is connected to ground is node E in fig. 4, and the node at which the second end of winding W2 is connected to conductor C is node B in fig. 4.

In one possible implementation, as shown in fig. 4, the switching power supply 1 may further include a filtering module 13. The input of the filtering module 13 may be connected to the ac power source S, and the output of the filtering module 13 may be connected to the nodes G and F.

In another possible implementation manner, referring to fig. 4, the transformation module 11 may include a diode D2 (i.e., a second diode), a diode D3 (i.e., a third diode), a diode D4 (i.e., a fourth diode), a diode D5 (i.e., a fifth diode), and a capacitor C2 (i.e., a second capacitor).

With continued reference to fig. 4, the transformation module 12 may further include a diode D1 (i.e., a first diode) and a capacitor C1 (i.e., a first capacitor).

The anode of the diode D1 and the drain (i.e., the first end) of the switching tube Q1 are both connected to the node a, and the first end of the winding W1 (i.e., the lower end of the winding W1 in fig. 4, i.e., the end close to the node a) is also connected to the node a. Node a is seen to be the node connecting diode D1 with winding W1. The cathode of the diode D1 may be connected to the node K, and the source (i.e., the second terminal) of the switch Q2 may be connected to the ground terminal. The positive terminal of the capacitor C1 may be connected to the node K, and the negative terminal of the capacitor C1 may be connected to the node I. The second end of winding W1 (i.e., the upper end of winding W1 in fig. 4) is connected to node J. The node J is connected with the node I, one end of the load L is connected with the node I, and the other end of the load L is connected with the node K.

It can be seen that the switching power supply shown in fig. 4 adopts a buck-boost circuit (which may have a voltage reduction function, a voltage boosting function, or a power transmission function), the conversion module 11 may convert (i.e., rectify) the ac power output by the ac power supply S into dc power, and the conversion module 12 may convert (i.e., invert) the dc power output by the conversion module 11 into ac power and provide the ac power to the load L (i.e., supply power to the load L).

A parasitic capacitance Cp1 exists between the devices connected by node a in fig. 4 (i.e., winding W1, switching tube Q1, and diode D1) and ground. The voltage at the node A generates a current in the parasitic capacitor Cp1, which flows back to the AC power source S through the first AC terminal of the AC power source S and the second AC terminal of the AC power source S, and thus the current can be referred to as a common mode current I₁. When the switch power supply is subjected to an electromagnetic interference test, the common-mode current I₁The presence of (a) may result in large common mode interference (i.e. the common mode interference exceeds a preset interference threshold).

Due to the device to which the node B is connected (i.e. the lead)A parasitic capacitance Cp2 exists between the body C) and the ground, and the node B generates a common mode current I on the parasitic capacitance Cp2₂. The value of the parasitic capacitance Cp2 can be changed by adjusting the area of the conductor C, or the voltage amplitude of the winding W2 can be changed by adjusting the number of turns of the winding W2, so that the common mode current I can be adjusted₂Of the amplitude of the common-mode current I₂Amplitude of and common mode current I₁Are equal in magnitude.

The switching power supply shown in fig. 4 according to the embodiment of the present application can pass the common mode current I₂Common mode current I₁And the common mode interference of the switching power supply is suppressed from the source.

In one possible implementation, as shown in fig. 5, the switching power supply 1 may also include a conversion module 11 and a conversion module 12 (i.e., a second conversion module).

Among them, the transformation module 11 may include an ac input terminal (i.e., node G and node F in fig. 5) and a first dc output terminal (i.e., node H in fig. 5), and the transformation module 12 may include a dc input terminal (i.e., node J in fig. 5) and a second dc output terminal (i.e., node I and node K in fig. 5).

Referring to fig. 5, the transformation module 22 may include an inductor L1 (i.e., a first inductor) and a switching tube Q1 connected to the inductor L1, the L1 inductor includes a winding W1 (i.e., a first winding) and a magnetic core MC, and a winding W1 is wound around the magnetic core MC.

The first end of winding W2 may be connected to ground or node H (in fig. 5, the first end of winding W2 is connected to ground for example), and the second end of winding W2 is connected to conductor C. The node at which the first end of winding W2 is connected to ground is node E in fig. 5, and the node at which the second end of winding W2 is connected to conductor C is node B in fig. 5.

In one possible implementation, as shown in fig. 5, the switching power supply 1 may further include a filtering module 13. The input of the filtering module 13 may be connected to the ac power source S, and the output of the filtering module 13 may be connected to the nodes G and F.

In another possible implementation manner, referring to fig. 5, the transformation module 11 may include a diode D2 (i.e., a second diode), a diode D3 (i.e., a third diode), a diode D4 (i.e., a fourth diode), a diode D5 (i.e., a fifth diode), and a capacitor C2 (i.e., a second capacitor).

With continued reference to fig. 5, the transformation module 12 may further include a diode D1 (i.e., a first diode), a capacitor C1 (i.e., a first capacitor), and a winding W3 (i.e., a third winding).

The drain (i.e., the first end) of the switching tube Q1 and the first end of the winding W1 (i.e., the lower end of the winding W1 in fig. 5, i.e., the end close to the node a) are both connected to the node a. As can be seen, node a may be the node connecting diode D1 with winding W1. The source (i.e., the second end) of the switching tube Q1 may be connected to the ground terminal, and the second end (i.e., the upper end of the winding W1 in fig. 5) of the winding W1 may be connected to the node J.

Winding W3 may be wound around the core, a first end of winding W3 (i.e., the upper end of winding W3 in fig. 5) may be connected to the anode of diode D1, a second end of winding W3 (i.e., the lower end of winding W3 in fig. 5) and the cathode of capacitor C1 are both connected to node K, and the cathode of diode D1 and the anode of capacitor C1 are both connected to node I. One end of the load L is connected with the node I, and the other end of the load L is connected with the node K.

Alternatively, the first end of the winding W1 (i.e., the end connected to the node a) and the second end of the winding W2 (i.e., the end connected to the node B) may be synonyms. The first end of the winding W1 and the second end of the winding W3 may be different terminals.

It can be seen that the switching power supply shown in fig. 5 adopts a flyback circuit (which may have a voltage reduction function, a voltage boosting function, or a power transmission function), the conversion module 11 may convert (i.e., rectify) the ac power output by the ac power supply S into dc power, and the conversion module 12 may convert (i.e., invert) the dc power output by the conversion module 11 into ac power and provide the ac power to the load L (i.e., supply power to the load L).

Parasitic capacitance Cp1 exists between the devices connected by node a in fig. 5 (i.e., winding W1 and switching tube Q1) and ground. The voltage at the node A generates a current in the parasitic capacitor Cp1, which flows back to the AC power source S through the first AC terminal of the AC power source S and the second AC terminal of the AC power source S, and thus the current can be referred to as a common mode current I₁. When the switch power supply is subjected to an electromagnetic interference test, the common-mode current I₁The presence of (a) may result in large common mode interference (i.e. the common mode interference exceeds a preset interference threshold).

Further, the synonym end relationship between the winding W1 and the winding W2 can be determinedThe phase of the voltage at node B is opposite to the phase of the voltage at node a. Therefore, the common mode current I₂Direction of (D) and common mode current I₂In the opposite direction.

The switching power supply shown in fig. 5 according to the embodiment of the present application can pass the common mode current I₂Common mode current I₁And the common mode interference of the switching power supply is suppressed from the source.

To sum up, the technical scheme provided by the embodiment of the application does not need to set additional filter devices such as a common-mode inductor at the alternating current input end of the switching power supply, and can fundamentally realize the suppression of the common-mode interference by connecting the conductor with the winding W2, and compared with the common-mode inductor, the suppression effect is obvious. And the switching power supply has low cost and small whole volume (namely small occupied space), and meets the requirement of miniaturization design.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The above description is only an exemplary embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A switching power supply is characterized by comprising a first conversion module and a second conversion module;

the first conversion module comprises an alternating current input end and a first direct current output end, and the second conversion module comprises a direct current input end and a second direct current output end;

the alternating current input end is used for being connected with an alternating current power supply, the first direct current output end is used for being connected with the direct current input end, and the second direct current output end is used for being connected with a load;

the second transformation module comprises a first inductor and a switching tube connected with the first inductor, the first inductor comprises a first winding and a magnetic core, and the first winding is wound on the magnetic core;

the second transformation module further comprises a second winding and a conductor, wherein the second winding is wound on the magnetic core to form a second inductor;

and the first end of the second winding is connected with a ground terminal or the first direct current output terminal, and the second end of the second winding is connected with a conductor.

2. The switching power supply according to claim 1, wherein the second conversion module further comprises a first diode and a first capacitor;

the positive pole of the first diode and the first end of the switch tube are connected with the first end of the first winding, the negative pole of the first diode is connected with the second direct current output end, the second end of the switch tube is connected with the grounding end, the second end of the first winding is connected with the direct current input end, the positive pole end of the first capacitor is connected with the second direct current output end, and the negative pole end of the first capacitor is connected with the grounding end.

3. The switching power supply according to claim 1, wherein the second conversion module further comprises a first diode and a first capacitor;

the positive pole of the first diode and the first end of the switch tube are connected with the first end of the first winding, the negative pole of the first diode is connected with the direct current input end, the second end of the switch tube is connected with the grounding end, and the positive pole end of the first capacitor, the negative pole end of the first capacitor and the second end of the first winding are connected with the second direct current output end.

4. The switching power supply according to claim 1, wherein the second conversion module further comprises a first diode and a first capacitor;

the positive pole of the first diode and the first end of the switch tube are connected with the first end of the first winding, the negative pole of the first diode is connected with the second direct current output end, the second end of the switch tube is connected with the grounding end, the second end of the first winding is connected with the direct current input end, and the positive pole end and the negative pole end of the first capacitor are connected with the second direct current output end.

5. The switching power supply according to claim 1, wherein the second conversion module further comprises a first diode, a first capacitor, and a third winding;

the first end of the switch tube is connected with the first end of the first winding, the second end of the switch tube is connected with the grounding end, and the second end of the first winding is connected with the direct-current input end;

the third winding is wound on the magnetic core, a first end of the third winding is connected with an anode of the first diode, a second end of the third winding is connected with a cathode of the first capacitor, and a cathode of the first diode and a positive end of the first capacitor are both connected with the second direct current output end.

6. The switching power supply according to claim 5, wherein the first end of the first winding and the second end of the third winding are opposite ends.

7. The switching power supply according to any one of claims 2 to 6, wherein the first end of the first winding and the second end of the second winding are opposite ends.

8. The switching power supply according to any one of claims 1 to 7, wherein the first conversion module comprises a second diode, a third diode, a fourth diode, a fifth diode, and a second capacitor;

the anode of the second diode and the cathode of the third diode are connected with the first alternating current end of the alternating current power supply, the cathode of the fourth diode and the anode of the fifth diode are connected with the second alternating current end of the alternating current power supply, the cathode of the second diode, the cathode of the fifth diode and the anode of the second capacitor are connected with the direct current input end, and the cathode of the third diode, the cathode of the fourth diode and the cathode of the second capacitor are connected with the grounding end.

9. The switching power supply according to any one of claims 1 to 8, wherein the conductor is a magnetic core.

10. The switching power supply according to any one of claims 1 to 9, further comprising a filter module, wherein an input terminal of the filter module is connected to the ac power supply, and an output terminal of the filter module is connected to the ac input terminal;

the filtering module is used for: and filtering the alternating current output by the alternating current power supply, and protecting the first conversion module.