Inductors, power factor correction circuits and power supply systems

Abstract

The present application provides an inductor, a power factor correction circuit, and a power supply system. The inductor includes a coil winding and a magnetic core; the magnetic core includes a first outer magnetic core, a second outer magnetic core, and a winding unit; the first outer magnetic core and the second outer magnetic core are arranged relative to each other along a first direction, the winding unit is arranged between the first outer magnetic core and the second outer magnetic core, and the coil winding is arranged around the winding unit; the winding unit includes a core column and at least two air gaps distributed along the first direction, and the axis of the core column is parallel to the first direction; the at least two air gaps include an air gap and at least one solid air gap; the magnetic induction intensity of the solid air gap is greater than the magnetic induction intensity of the core column. The total air gap of the inductor can vary with the current of the coil winding. When applied to the power factor correction circuit of the power supply system, it can make the inductance of the light-load section of the power supply system large, improve the working efficiency of the power factor correction circuit, and thus optimize the efficiency of the light-load section of the power supply system.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to inductors, power factor correction circuits, and power supply systems. Background Art

[0002] Power supply systems are widely used in various power supply applications, including servers, data centers, and base stations. To address the increasing energy consumption associated with technological advancements, the demand for power system efficiency is increasing, particularly for the efficiency of power factor correction (PFC) circuits within these systems. Improving the efficiency of PFC circuits in critical conduction mode is crucial for improving power system efficiency. Summary of the Invention

[0003] The present application provides an inductor, a power factor correction circuit, and a power supply system, so that the light-load section of the critical conduction mode of the power supply system has higher operating efficiency, thereby improving the power supply efficiency.

[0004] In the first aspect, the present application provides an inductor that can be applied to a power factor correction circuit. The inductor includes a coil winding and a magnetic core. The magnetic core includes a first outer magnetic core, a second outer magnetic core and a winding unit, the first outer magnetic core and the second outer magnetic core are arranged relative to each other along a first direction, the winding unit is arranged between the first outer magnetic core and the second outer magnetic core, and the coil winding is arranged around the winding unit. Specifically, the winding unit includes a magnetic core center column and at least two air gaps distributed along the first direction, and the direction of the axis of the magnetic core center column is parallel to the first direction. The at least two air gaps are used to realize the segmented air gap of the magnetic core. The at least two air gaps include an air air gap and at least one solid air gap. The magnetic induction intensity of the solid air gap is greater than that of the magnetic core center column. The magnetic induction intensity refers to the density of magnetic flux lines passing through a unit area (the unit area is perpendicular to the first direction).

[0005] For a magnetic core, as the magnetic flux increases, the solid air gap reaches magnetic flux saturation earlier than the core's center leg. When the magnetic flux in the solid air gap reaches saturation, the magnetic flux within the solid air gap rapidly decays, eventually causing the solid air gap to function as an air gap. When the magnetic flux is relatively small, the solid air gap magnetic flux is not saturated, and the solid air gap can function as a magnetic conductor. At this point, the total air gap of the entire core equals the air gap. As the magnetic flux gradually increases until the solid air gap reaches magnetic flux saturation, the magnetic flux in the solid air gap rapidly decays, eventually causing the solid air gap to function as another air gap. At this point, the total air gap of the entire core equals the sum of the air gap and the solid air gap. In other words, the total air gap size of the magnetic core can be adjusted according to the current in the coil winding.

[0006] When this inductor is applied to the power factor correction circuit of a power supply system, when the power supply system is in the critical conduction mode and light load segment, the air gap of the inductor is equivalent to the air gap in the original structure. The large inductance of the inductor can reduce the switching frequency of the power factor correction circuit, thereby reducing the loss of the metal oxide semiconductor field effect transistor (MOSFET) switch in the power factor correction circuit, which is equivalent to improving the efficiency of the power supply system in the light load segment. As the load of the power supply system increases, the solid air gap saturates with the increase in load, and the solid air gap acts as another air gap. At this time, the total air gap is equivalent to the sum of the air gap and the solid air gap. The total air gap of the inductor increases, and the inductance of the inductor decreases, which can improve the switching frequency of the power factor correction circuit. It can be seen that the application of the above-mentioned magnetic core to the power supply system can make the power factor correction circuit have a higher operating efficiency when the power supply system is in the critical conduction mode and light load segment, so that the power supply system also has a higher efficiency in the light load segment, thereby improving the efficiency of the power supply system and meeting the demand for high-efficiency power supply.

[0007] The structure of the winding unit can be implemented in various ways. The center column of the magnetic core can be fixed to the first outer magnetic core, and an air gap is formed between the center column of the magnetic core and the second outer magnetic core; or, the center column of the magnetic core is fixed to the second outer magnetic core, and an air gap is formed between the center column of the magnetic core and the first outer magnetic core; or, the center column of the magnetic core includes a first sub-column and a second sub-column, the first sub-column is fixed to the first outer magnetic core, and the second sub-column is fixed to the second outer magnetic core; an air gap is formed between the first sub-column and the second sub-column.

[0008] In some possible implementations, an air gap may be disposed adjacent to a solid gap.

[0009] In some possible implementations, the magnetic core center column includes a plurality of inner magnetic cores, and the air gap and the solid gap are respectively arranged on two sides of an inner magnetic core along the first direction.

[0010] The material of the solid air gap can be ferromagnetic or ferromagnetic powder, or other iron oxide mixtures.

[0011] In one possible implementation, the center of the solid air gap has a hollow area that penetrates the solid air gap along a first direction. The hollow area can increase the magnetic induction intensity of the solid air gap, so that the magnetic induction intensity of the solid air gap is greater than the magnetic induction intensity of the core center column. In addition, the solid air gap of this structure is a closed ring, so that the solid air gap can reduce the eddy current loss generated by the leakage magnetic flux on the peripheral coils, thereby improving the power supply efficiency. The hollow area can be cylindrical, and the hollow area is coaxial with the core center column. The circumferential surface of the solid air gap is flush with the circumferential surface of the core center column, which facilitates the coil winding to be arranged around the winding unit. Specifically, the solid air gap can be bonded to the core center column by an adhesive, an adhesive layer, etc.

[0012] In a possible implementation, a radial dimension of the solid air gap perpendicular to the first direction is greater than a radial dimension of the central column of the magnetic core perpendicular to the first direction.

[0013] The first outer magnetic core includes a first base and two first side legs, which are fixed to the first base and extend toward the second outer magnetic core. The second outer magnetic core includes a second base and two second side legs, which are fixed to the second base and extend toward the first outer magnetic core. The ends of the core center leg are fixed to the first base and the second base, respectively, with the two first side legs and the two second side legs correspondingly connected. The first and second outer magnetic cores can be any of EE, EP, PQ, or RM types.

[0014] Since the total air gap of the magnetic core in the inductor can be changed according to the load of the power system, when the power system is in the critical conduction mode, the inductor can have a larger inductance in the light-load section of the power system and a smaller inductance in the heavy-load section of the power system.

[0015] In a second aspect, the present application also provides a power factor correction circuit, comprising a capacitor, a metal oxide semiconductor field effect transistor switch, a diode and the above-mentioned inductor. One end of the inductor is connected to the output end of the rectifier circuit for receiving the output current of the rectifier circuit, and the other end of the inductor is connected to the anode of the diode and one end of the metal oxide semiconductor field effect transistor switch. The cathode of the diode is connected to the input end of the DC transformer circuit and the capacitor. When the power supply system is in the critical conduction mode, the metal oxide semiconductor field effect transistor switch in the power factor correction circuit has low loss in the light load section of the power supply system, so that the power factor correction circuit has higher working efficiency when the power supply system is in the light load section of the critical conduction mode, so that the power supply system also has higher efficiency in the light load section, thereby improving the efficiency of the power supply system.

[0016] On the third aspect, the present application also provides a power supply system, which includes an AC-DC conversion circuit, a DC transformer circuit, and a control circuit. Among them, the AC-DC conversion circuit includes a rectifier circuit and the above-mentioned power factor correction circuit. When the power supply system is in critical conduction mode, the power factor correction circuit has a higher working efficiency when the power supply system is in the light load section of the critical conduction mode, so that the power supply system also has a higher efficiency in the light load section, thereby improving the efficiency of the power supply system and meeting the high-efficiency power supply requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1a is a schematic diagram of the power supply system;

[0018] Figure 1b is a schematic diagram of an AC-DC conversion circuit;

[0019] Figure 1c for Figure 1b The inductor current waveform of the power factor correction circuit shown in the critical conduction mode;

[0020] Figure 2 A schematic diagram of an inductor provided in an embodiment of the present application;

[0021] Figure 3a A schematic diagram of the structure of an inductor provided in an embodiment of the present application;

[0022] Figure 3b A schematic diagram of the structure of an inductor provided in an embodiment of the present application;

[0023] Figure 3c A front view of an inductor provided in an embodiment of the present application;

[0024] Figure 4 An exploded diagram of an inductor provided in an embodiment of the present application;

[0025] Figure 5 A schematic structural diagram of a solid air gap in an inductor provided in an embodiment of the present application;

[0026] Figure 6a An exploded diagram of an inductor provided in an embodiment of the present application;

[0027] Figure 6b and Figure 6c A schematic structural diagram of a solid air gap in an inductor provided in an embodiment of the present application;

[0028] Figures 7a and 7b A schematic structural diagram of a solid air gap in an inductor provided in an embodiment of the present application;

[0029] Figure 8 A front view of an inductor provided in an embodiment of the present application;

[0030] Figure 9 A schematic diagram of the distribution of magnetic flux lines of an inductor provided in an embodiment of the present application;

[0031] Figure 10a and Figure 10b A schematic diagram of the structure of an inductor provided in an embodiment of the present application;

[0032] Figures 11a to 11c A schematic diagram of the structure of an inductor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] Figure 1a Schematic diagram of a power supply system. The power supply system 100 is used to receive AC power provided by an AC power source 200 and output DC power to a DC load 300. The DC load 300 includes a server, a data center, a base station, a home appliance, or a lighting device. Figure 1a As shown, the power supply system 100 includes an alternating current / direct current (AC / DC) conversion circuit 110 , a DC transformer circuit 120 and a control circuit 130 .

[0034] Figure 1b Figure 1 is a schematic diagram of an AC / DC conversion circuit. Figure 1b As shown, the AC / DC conversion circuit 110 includes a rectifier circuit 111 and a power factor correction (PFC) circuit 112. The input end of the AC / DC conversion circuit 110 is connected to the AC power source 200, and the output end is connected to the AC power source 200. Figure 1a The DC transformer circuit 120 shown. The AC / DC converter circuit 110 is also provided with an analog ground (AGND). The input end of the rectifier circuit 111 is connected to the AC power supply 200, and the output end is connected to the power factor correction circuit 112. The rectifier circuit 111 includes four diodes (D1, D2, D3, D4), each of which can allow AC current to flow through when it flows in the forward direction and block the current when the current flows in the reverse direction. The power factor correction circuit 112 includes an inductor L1, a capacitor C, a diode D0, and a metal oxide semiconductor field effect transistor Q1. One end of the inductor L1 is connected to the output end of the rectifier circuit 111 for receiving the output current of the rectifier circuit 111, and the other end of the inductor L1 is connected to the anode of the diode D0 and one end of the metal oxide semiconductor field effect transistor switch Q1. The cathode of the diode D0 is connected to the input end of the DC transformer circuit 120 and the capacitor C. It can be understood that the inductor L1 stores energy when the MOSFET switch Q1 is turned on, and when the MOSFET switch Q1 is turned off, the inductor L1 charges the capacitor C through the diode D0 using the energy stored when the MOSFET switch Q1 is turned on.

[0035] Figure 1c The waveform (forward current) of the inductor L1 during half a current cycle of the power factor correction circuit in critical conduction mode is shown. The horizontal axis is time t and the vertical axis is current I. The current on the inductor L1 shows a toothed shape with the on-time of the MOSFET switch Q1. T on Refers to the period during which the MOSFET switch Q1 is turned on, T off Refers to the MOSFET switch Q1 cut-off period, T s This is equivalent to the switching cycle of the MOSFET switch Q1, and the peak value of the current waveform of the inductor L1 is connected to form a curve I peak , the peak value of the current waveform of inductor L1 is connected to form curve I average Among them, the MOSFET switch Q1 can achieve zero current / zero voltage turn-on, with low turn-on loss; the current of the inductor L1 critically crosses zero, making this mode free from the diode reverse recovery problem. However, the switching frequency of this power factor correction circuit is high in the light load section, and the switching loss of the MOSFET switch Q1 is large. The frequency of the MOSFET switch Q1 is related to three factors: the input voltage, the inductor inductance, and the output load size. Under the conditions of the power supply input voltage and output load current, the frequency of the MOSFET switch Q1 is determined by the inductor in the power factor correction circuit. If the inductor inductance can be large in the light load section and small in the heavy load section, the frequency of the MOSFET switch Q1 in the light load section can be reduced, reducing the switching loss of the MOSFET Q1 and thereby improving the power supply efficiency.

[0036] Among them, the calculation formula of inductance is:

[0037]

[0038] μ0 represents the vacuum permeability, μ0=4π×10 -7 H / m, N represents the number of turns of inductance, A e Represents the effective cross-sectional area of ​​the core, and δ represents the air gap opened by the core. After the coil winding and core shape of the inductor are selected, N and A e Considered a constant, the δ air gap becomes the only variable in the formula that affects the inductance. Existing inductors, including single-segment and segmented air gaps, have fixed air gap sizes, and the inductance cannot be adjusted by changing the air gap size.

[0039] Based on this, the embodiments of the present application provide an inductor, a power factor correction circuit, and a power supply system to solve the above problems. In order to make the purpose, technical solution, and advantages of the present application more clear, the present application will be further described in detail below with reference to the accompanying drawings.

[0040] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a", "an", "said", "above", "the", and "this" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise.

[0041] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0042] Figure 2 This is a schematic diagram of an inductor provided in an embodiment of the present application. Figure 2 As shown, the inductor includes a magnetic core 10 and a coil winding 6. The magnetic core 10 includes a first outer magnetic core 1, a second outer magnetic core 2, and a winding unit R. The coil winding 6 is disposed around the winding unit R. It is understood that the coil winding 6 can specifically be a multi-strand wire, an excitation wire, a circuit board winding, etc., and is certainly not limited to the examples shown here. For ease of illustration, the inductor's coil winding 6 is hidden in the subsequent figures.

[0043] Figure 3a This is a schematic diagram of the structure of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. Figure 3a As shown, the magnetic core 10 includes a first outer magnetic core 1, a second outer magnetic core 2, and a winding unit R. The first outer magnetic core 1 and the second outer magnetic core 2 are arranged relative to each other along a first direction, and the winding unit R is arranged between the first outer magnetic core 1 and the second outer magnetic core 2. It should be understood that the first direction here includes both the direction from the first outer magnetic core 1 to the second outer magnetic core 2 and the direction from the second outer magnetic core 2 to the first outer magnetic core 1.

[0044] The first outer magnetic core 1 specifically includes a first base 11 and two first side columns 12. The two first side columns 12 are fixed to the first base 11, and the two first side columns 12 extend toward the second outer magnetic core 2. Correspondingly, the second outer magnetic core 2 specifically includes a second base 21 and two second side columns 22. The two second side columns 22 are fixed to the second base 21, and the two second side columns 22 extend toward the first outer magnetic core 1. In one embodiment of the present application, the two first side columns 12 and the two second side columns 22 are matched and connected in a one-to-one correspondence, and the connection between the first side column 12 and the corresponding second side column 22 can be a fixing method such as bonding and clamping. The first base 11 and the two first side columns 12 in the first outer magnetic core 1 can be an integrated structure, and the second base 21 and the second side column 22 in the second outer magnetic core 2 can be an integrated structure. In another embodiment of the present application, the first side column 12 and the corresponding second side column 22 can be integral, the connection between the first base 11 and the first side column 12 can be a fixing method such as bonding, clamping, etc., and the connection between the second base 21 and the second side column 22 can be a fixing method such as bonding, clamping, etc. It should be understood that in the embodiment of the present application, there may be a gap at the junction of the first side column 12 and the second side column 22, the junction of the first base 11 and the first side column 12, and the junction of the second base 21 and the second side column 22. It can be understood that the first outer magnetic core 1 and the second outer magnetic core 2 in the accompanying drawings of the embodiment of the present application are only examples, and the first outer magnetic core 1 and the second outer magnetic core 2 can be any one of EE type, EP type, PQ type or RM type. Among them, the material of the first outer magnetic core 1 and the second outer magnetic core 2 can be ferromagnetic or ferromagnetic powder, and can also be other iron oxide mixtures such as sendust.

[0045] Figure 3b This is a schematic diagram of the structure of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. Figure 3b As shown, the winding unit R includes a core column 3 and at least two air gaps. The axis of the core column 3 is parallel to the first direction. The at least two air gaps are specifically exemplified as an air gap 41 and at least one solid gap 42. Figure 3bThe ends of the core column 3 along the first direction are respectively fixed to the first base 11 and the second base 21. The core column 3 can be divided into at least three sections along the first direction, forming at least three inner magnetic cores (for example, the first inner magnetic core 31a, the second inner magnetic core 31b, and the third inner magnetic core 31c). The first inner magnetic core 31a is fixed to the first base 11, and the first inner magnetic core 31a and the first base 11 can be an integral structure. The third inner magnetic core 31c is fixed to the second base 21, and the third inner magnetic core 31c and the second base 21 can be an integral structure. The second inner magnetic core 31b is arranged between the first inner magnetic core 31a and the third inner magnetic core 31c. A solid air gap 42 is arranged between the first inner magnetic core 31a and the second inner magnetic core 31b, and an air gap 41 is arranged between the second inner magnetic core 31b and the third inner magnetic core 31c. The air gap 41 and the solid air gap 42 here can realize the segmentation of the core column 3 and reduce the eddy current loss generated by the coil winding around the core column 3. In other embodiments of the present application, the air gap 41 can be set between the first inner magnetic core 31a and the second inner magnetic core 31b, and the solid air gap 42 can be set between the second inner magnetic core 31b and the third inner magnetic core 31c. It can be understood that the air gap 41 and the solid air gap 42 can be set between any two adjacent inner magnetic cores. Among them, the material of the core column 3 can be ferromagnetic or ferromagnetic powder, or other iron oxide mixtures such as sendust. The material of the solid air gap 42 can be ferromagnetic, or ferromagnetic powder, or other iron oxide mixtures such as sendust.

[0046] Figure 3c This is a front view of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. Figure 3cAs shown, the first outer magnetic core 1 and the second outer magnetic core 2 are arranged opposite to each other along a first direction. The first outer magnetic core 1 includes a first base 11 and two first side columns 12 connected to both sides of the first base 11. The second outer magnetic core 2 includes a second base 21 and two second side columns 22 connected to the second base 21. The winding unit 6 includes a magnetic core center column 3, an air gap 41, and a solid air gap 42. The magnetic core center column 3 includes a first sub-column 3a and a second sub-column 3b. The first sub-column 3a is fixed to the first base 11, and the second sub-column 3b is fixed to the second base 21. The air gap 41 is provided between the first sub-column 3a and the second sub-column 3b, and the solid air gap 42 is provided in the first sub-column 3a. It can be understood that the air gap 41 divides the magnetic core center column 3 into a first sub-column 3a (i.e., the first inner magnetic core 31a and the second inner magnetic core 31b) and a second sub-column 3b (i.e., the third inner magnetic core 31c). Specifically, the magnetic core center column 3 includes a first inner magnetic core 31a, a second inner magnetic core 31b, and a third inner magnetic core 31c along the first direction. The first inner magnetic core 31a is fixed to the first base 11, and the third inner magnetic core 31c is fixed to the second base 21. The second inner magnetic core 31b is disposed between the first and third inner magnetic cores 31a, 3c. An air gap 41 is disposed between the second and third inner magnetic cores 31b, 31c. A solid air gap 42 is disposed between the first and second inner magnetic cores 31a, 31b. It is understood that the second inner magnetic core 31b is located between the air gap 41 and the solid air gap 42.

[0047] Reference Figure 4 As shown, the first outer magnetic core 1 and the second outer magnetic core 2 are arranged opposite to each other along the first direction. The first outer magnetic core 1 includes a first base 11 and two first side columns 12 connected to both sides of the first base 11. The second outer magnetic core 2 includes a second base 21 and two second side columns 22 connected to the second base 21. The core center column 3 is connected between the first base 11 and the second base 21. The core center column 3 includes a first inner magnetic core 31a, a second inner magnetic core 31b, and a third inner magnetic core 31c along the first direction. A solid air gap 42 is provided between the first inner magnetic core 31a and the second inner magnetic core 31b. The structure of the solid air gap 42 can be referred to Figure 5 .

[0048] like Figure 5As shown, the center of the solid air gap 42 is provided with a hollow area Q that passes through the solid air gap 42 along the first direction. In this embodiment, the hollow area Q is cylindrical, and the orthographic projection of the hollow area Q on the first outer magnetic core 1 or the second outer magnetic core 2 is a circle, and the center of the circular projection is located on the axis of the core center column 3. The hollow area Q is coaxial with the core center column 3, that is, the axis of the hollow area Q is colinear with the axis of the core center column 3. It can be understood that the hollow area Q can also be of other shapes. The circumferential surface of the solid air gap 42 can be flush with the circumferential surface of the core center column 3, so that the solid air gap 42 can be kept neat with the circumferential surface of the core center column 3, which is conducive to the coil winding being arranged around the winding unit R.

[0049] Magnetic induction intensity is the number of magnetic flux lines that can pass through a unit area, which is perpendicular to the Figure 4 and Figure 5 The first direction shown. Due to the presence of the hollow area Q, the magnetic induction intensity of the solid air gap 42 is greater than the magnetic induction intensity of the core center column 3. When the current of the coil winding 6 is small and the magnetic flux of the solid air gap 42 is not saturated, the solid air gap 42 plays the role of magnetic conduction. At this time, the total air gap of the magnetic core 10 is equivalent to the air gap 41. When the current of the coil winding 6 increases and the magnetic flux of the solid air gap 42 is saturated, the magnetic flux of the solid air gap 42 decays rapidly, and finally the solid air gap 42 plays the role of an air gap. At this time, the total air gap of the magnetic core 10 is equivalent to the superposition of the air gap 41 and the solid air gap 42. Here, the solid air gap 42 is equivalent to a magnetic closed ring, so that the solid air gap 42 can reduce the eddy current loss generated by the leakage magnetic flux on the surrounding coil windings.

[0050] like Figure 6a Therefore, the structure of the magnetic core 10 is Figure 4 The structure of the magnetic core 10 is similar. The difference is that Figure 6a The solid air gap 42 in the illustrated magnetic core 10 is circular, and its radial dimension (the dimension perpendicular to the first direction) is smaller than the radial dimension of the core's center leg 3. This smaller radial dimension allows the solid air gap 42 to have a greater magnetic flux density than the core's center leg 3. When the magnetic flux in the solid air gap 42 has not reached saturation, the solid air gap 42 can function as a magnetic conductor. When the magnetic flux in the solid air gap 42 reaches saturation, the magnetic flux in the solid air gap 42 rapidly decays, and the solid air gap 42 eventually functions as an air gap.

[0051] Figure 6b Schematic diagram of a solid air gap in the inductor provided in the embodiment of the present application. Figure 6bAs shown, the solid air gap 42 has a first surface a1 and a second surface a2 that are parallel to each other along a first direction. The radial dimension of the first surface a1 is smaller than the radial dimension of the second surface a2. The radial dimension of the second surface a2 can be smaller than or equal to the radial dimension of the magnetic core center leg 3. It is understood that the first surface a1 and the second surface a2 can also form an angle, that is, the first surface a1 and the second surface a2 are not parallel.

[0052] Figure 6c Schematic diagram of a solid air gap in the inductor provided in the embodiment of the present application. Figure 6c As shown, the solid air gap 42 has a first surface a1 and a second surface a2 along a first direction. The first surface a1 and the second surface a2 form an angle, that is, the first surface a1 and the second surface a2 are not parallel. The radial dimension of the second surface a2 can be smaller than the radial dimension of the core leg 3.

[0053] Reference Figure 5 and Figure 6b The structure of the solid air gap 42 can also be as follows Figure 7a As shown. The solid air gap 42 has a first surface a1 and a second surface a2 that are parallel to each other. The solid air gap 42 has a hollow region Q that extends through the first surface a1 and the second surface a2. Along the first direction, the radial dimension of the first surface a1 is smaller than the radial dimension of the second surface a2, and the radial dimension of the second surface a2 can be smaller than the radial dimension of the magnetic core center leg 3. It is understood that the first surface a1 and the second surface a2 can also form an angle, that is, the first surface a1 and the second surface a2 are not parallel.

[0054] Reference Figure 5 and Figure 6c The structure of the solid air gap 42 can also be as follows Figure 7b As shown. The solid air gap 42 has a first surface a1 and a second surface a2, with the first surface a1 and the second surface a2 forming an angle therebetween. Along a first direction, the solid air gap 42 has a hollow region Q extending through the first surface a1 and the second surface a2. In this embodiment, the radial dimension of the second surface a2 of the solid air gap 42 can be less than or equal to the radial dimension of the magnetic core center leg 3.

[0055] It should be understood that the above embodiment only provides a simple example of the structure of the solid air gap 42. The structure of the solid air gap 42 may also be implemented in other ways, such as a cube, a polyhedron, or even an irregular shape, as long as the magnetic induction intensity of the solid air gap 42 can be greater than the magnetic induction intensity of the magnetic core column 3, so that the solid air gap 41 can play the role of magnetic conduction or air gap when the magnetic flux changes.

[0056] Figure 8This is a front view of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. Figure 8 As shown, a first outer magnetic core 1 and a second outer magnetic core 2 are arranged opposite each other along a first direction. The first outer magnetic core 1 includes a first base 11 and two first side legs 12 connected to either side of the first base 11. The second outer magnetic core 2 includes a second base 21 and two second side legs 22 connected to the second base 21. A core center leg 3 is connected between the first base 11 and the second base 21. The core center leg 3 includes a first inner magnetic core 31a and a second inner magnetic core 31b along the first direction. The first inner magnetic core 31a is fixed to the first base 11, and the second inner magnetic core 31b is fixed to the second base 21. An air gap 41 is adjacent to the solid air gap 42 and is disposed between the first inner magnetic core 31a and the second inner magnetic core 31b. Specifically, the solid air gap 42 is disposed on the side of the second inner magnetic core 31b facing the first inner magnetic core 31a, the second surface a2 of the solid air gap 42 is fixed to the surface of the second inner magnetic core 31b facing the first inner magnetic core 31a, and an air gap 41 is disposed between the solid air gap 42 and the first inner magnetic core 31a. It will be appreciated that the solid air gap 42 may also be disposed on the side of the first inner magnetic core 31a facing the second inner magnetic core 31b, the second surface a2 of the solid air gap 42 being fixed to the surface of the first inner magnetic core 31a facing the second inner magnetic core 31b, and the air gap 41 being disposed between the solid air gap 42 and the second inner magnetic core 31b.

[0057] Figure 9 This is a schematic diagram of the magnetic flux distribution of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. For the convenience of display, only three groups of magnetic flux lines are illustrated here with dotted lines, and the arrow directions are only examples. Figure 9As shown, after the coil winding 6 of the winding unit R is energized, multiple magnetic flux lines pass through the core center column 3 and the solid air gap 42. The current of the coil winding 6 is positively correlated with the magnetic flux in the magnetic core 10 within a certain range. Therefore, when the current of the coil winding 6 increases, the magnetic flux of the core center column 3 and the solid air gap 42 will increase accordingly. According to the above embodiment, the magnetic induction intensity of the solid air gap 42 is less than the magnetic induction intensity of the core center column 3. As the current of the coil winding 6 increases, the solid air gap 42 will reach the magnetic flux saturation state earlier than the core center column 3. When the magnetic flux of the solid air gap 42 reaches saturation, the magnetic flux in the solid air gap 42 rapidly decays and eventually causes the solid air gap 42 to play the role of an air gap. That is to say, when the current of the coil winding 6 is relatively small, the magnetic flux of the solid air gap 42 is not saturated. Since the material of the solid air gap 42 is a magnetic material, the solid air gap 42 can play the role of magnetic conduction similar to the core leg 3. At this time, the total air gap size of the inductor is equal to the size of the air gap 41. When the current of the coil winding 6 increases and the magnetic flux of the solid air gap 42 is saturated, the magnetic flux of the solid air gap 42 rapidly decays, and eventually the solid air gap 42 will play the role of an air gap. At this time, the total air gap size of the inductor is equal to the size of the air gap 41 plus the size of the solid air gap 42. As the total air gap of the inductor increases, the inductance of the inductor decreases. It can be understood that the solid air gap 42 of the inductor provided in the embodiment of the present application can play the role of magnetic conduction or air gap according to the change of magnetic flux. Therefore, the total air gap of the inductor can change according to the change of the current of the coil winding 6, so that the inductance of the inductor can change according to the change of the current of the coil winding 6.

[0058] Figure 10a and Figure 10b This is a front view of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. Figure 10a and Figure 10b As shown, the first outer magnetic core 1 and the second outer magnetic core 2 are arranged opposite to each other along the first direction. The first outer magnetic core 1 includes a first base 11 and two first side columns 12 connected to both sides of the first base 11. The second outer magnetic core 2 includes a second base 21 and two second side columns 22 connected to the second base 21. The core center column 3 can be fixedly connected to the first outer magnetic core 1 or the second outer magnetic core 2, and an air gap 41 can be formed between the core center column 3 and the first outer magnetic core 1 or between the core center column 3 and the second outer magnetic core 2. Figure 10a In the figure, the core center column 3 includes a first inner magnetic core 31a and a second inner magnetic core 31b distributed in sequence along the first direction. The first inner magnetic core 31a is fixed to the first base 11 of the first outer magnetic core 1. A solid air gap 42 is set between the first inner magnetic core 31a and the second inner magnetic core 31b, and an air gap 41 is formed between the second inner magnetic core 31b and the second base 21 of the second outer magnetic core 2. Figure 10bIn the embodiment, the core column 3 includes a first inner magnetic core 31a and a second inner magnetic core 31b distributed in sequence along the first direction. The second inner magnetic core 31b is fixed to the second base 21 of the second outer magnetic core 2. A solid air gap 42 is provided between the first inner magnetic core 31a and the second inner magnetic core 31b, and an air gap 41 is formed between the first inner magnetic core 31a and the first base 11 of the first outer magnetic core 1. It is understandable that the core column 3 in this embodiment can also include more inner magnetic cores, and air gaps and / or solid air gaps can be provided between adjacent inner magnetic cores. The air gap 41 and the solid air gap 42 can be respectively provided on both sides of an inner magnetic core along the first direction, and the air gap 41 and the solid air gap 42 can also be provided adjacent to each other between two inner magnetic cores.

[0059] Figure 11a 、 Figure 11b 、 Figure 11c This is a front view of an inductor provided in an embodiment of the present application. For the convenience of display, the coil winding 6 of the inductor is hidden in the figure. Figures 11a to 11c As shown, the first outer magnetic core 1 and the second outer magnetic core 2 are opposite to each other along a first direction. The first outer magnetic core 1 includes a first base 11 and two first side columns 12 connected to both sides of the first base 11. The second outer magnetic core 2 includes a second base 21 and two second side columns 22 connected to the second base 21. The core center column 3 is disposed between the first base 11 and the second base 21.

[0060] exist Figure 11a In the embodiment, the magnetic core center column 3a includes a first inner magnetic core 31a, a second inner magnetic core 31b, a third inner magnetic core 31c, and a fourth inner magnetic core 31d, arranged in sequence along a first direction. The first inner magnetic core 31a is fixed to the first base 11, and the fourth inner magnetic core 31d is fixed to the second base 21. A solid air gap 42a is provided between the first inner magnetic core 31a and the second inner magnetic core 31b. A solid air gap 42b is provided between the second inner magnetic core 31b and the third inner magnetic core 31c. An air gap 41 is formed between the third inner magnetic core 31c and the fourth inner magnetic core 31d.

[0061] exist Figure 11b In the embodiment, the magnetic core center column 3a includes a first inner magnetic core 31a, a second inner magnetic core 31b, a third inner magnetic core 31c, and a fourth inner magnetic core 31d, arranged in sequence along a first direction. The first inner magnetic core 31a is fixed to the first base 11, and the fourth inner magnetic core 31d is fixed to the second base 21. A solid air gap 42a is provided between the first inner magnetic core 31a and the second inner magnetic core 31b. A solid air gap 42b is provided between the third inner magnetic core 31c and the fourth inner magnetic core 31d. An air gap 41 is formed between the second inner magnetic core 31b and the third inner magnetic core 31c.

[0062] exist Figure 11cIn the embodiment, the magnetic core center column 3a includes a first inner magnetic core 31a, a second inner magnetic core 31b, a third inner magnetic core 31c, and a fourth inner magnetic core 31d, which are arranged in sequence along a first direction. The first inner magnetic core 31a is fixed to the first base 11, and the fourth inner magnetic core 31d is fixed to the second base 21. An air gap 41 is provided between the first inner magnetic core 31a and the second inner magnetic core 31b. A solid air gap 42b is provided between the second inner magnetic core 31b and the third inner magnetic core 31c. A solid air gap 42a is provided between the third inner magnetic core 31c and the fourth inner magnetic core 31d.

[0063] The air gap of the inductor provided in the embodiment of the present application includes a combination of an air gap 41 and a solid air gap 42. The combination of the air gap 41 and the solid air gap 42 can be one solid air gap 42 and multiple air gaps 41, multiple solid air gaps 42 and one air gap 41, or multiple solid air gaps 42 and multiple air gaps 41. It is understood that the air gap 41 and the solid air gap 42 can be arranged adjacent to each other, or the air gap 41 and the solid air gap 42 can be respectively arranged on both sides of an inner magnetic core along the first direction.

[0064] The solid air gap 42 of the inductor provided in the embodiment of the present application can function as a magnetic conduction or air gap according to changes in magnetic flux, so that the total air gap of the inductor can be varied according to changes in the current of the coil winding 6, and further, the inductance of the inductor can be varied according to changes in the current of the coil winding 6. Therefore, the inductor provided in the embodiment of the present application can be applied to power factor correction circuits, AC-DC conversion circuits, and power supply systems to improve the efficiency of the power factor correction circuits, AC-DC conversion circuits, and power supply systems.

[0065] Accordingly, the embodiment of the present application also provides a power factor correction circuit, an AC / DC conversion circuit, and a power supply system. The structure of the power factor correction circuit provided in the embodiment of the present application can refer to Figure 1b The power factor correction circuit 112 shown is different in that Figure 1b The inductor L1 in the embodiment of the present application can be replaced by the inductor provided in the embodiment of the present application. Figure 1b The AC-DC conversion circuit 110 shown in FIG. Figure 1b The inductor L1 in the embodiment of the present application can be replaced by the inductor provided in the embodiment of the present application. Figure 1a The power supply system 100 shown is different in that Figure 1a The AC-DC conversion circuit 110 in the embodiment uses the inductor provided in the above embodiment of the present application.

[0066] In critical conduction mode, when the power supply system 100 provided in the embodiment of the present application operates in a light-load segment, the current of the inductor L1 of the power factor correction circuit 112 in the AC / DC conversion circuit 110 is relatively small, the current of the coil winding 6 of the inductor L1 is relatively small, and the magnetic flux of the solid air gap 42 of the inductor L1 has not reached saturation. The solid air gap 42 can play a similar magnetic conduction role as the inner magnetic core 31. At this time, the total air gap size of the inductor is equivalent to the size of the air gap 41. Therefore, when the power supply system 100 operates in a light-load segment, the inductor has a large inductance, which can reduce the switching frequency of the power factor correction circuit 112, thereby reducing the loss of the MOSFET switch, which is equivalent to improving the efficiency of the power supply system in the light-load segment, thereby improving the efficiency of the power supply system 100. As the load of the power supply system 100 increases, the current of the inductor L1 of the power factor correction circuit 112 in the AC / DC conversion circuit 110 increases, the current of the coil winding 6 of the inductor L1 increases, and the magnetic flux of the solid air gap 42 gradually increases to saturation. The magnetic flux of the solid air gap 42 decays rapidly, and finally the solid air gap 42 plays the role of an air gap. At this time, the total air gap of the inductor is equivalent to the superposition of the air gap 41 and the solid air gap 42. The total air gap of the inductor increases, and the inductance of the inductor decreases. Therefore, when the power supply system 100 is operating in the heavy load section, the inductance of the inductor is small, which can increase the switching frequency of the power factor correction circuit 112, thereby avoiding abnormal noise caused by the MOSFET switch being too low in frequency.

[0067] It is understood that the power factor correction circuit and AC-DC conversion circuit provided by the embodiments of the present application can reduce the switching frequency of the MOSFET switch in critical conduction mode when the power system is lightly loaded, thereby reducing the losses of the MOSFET switch and optimizing the efficiency of the power factor correction circuit in the light-load range of the power system. When the power system is heavily loaded, the switching frequency of the MOSFET switch can be increased to avoid abnormal noise caused by the MOSFET switch being too low in frequency.

[0068] It can be understood that the power supply system provided in the embodiment of the present application has higher working efficiency in the light-load section of the power supply system in the critical conduction mode, which can improve the efficiency of the power supply system and meet the high-efficiency power supply requirements.

[0069] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An inductor, characterized in that: The invention comprises a coil winding and a magnetic core; the magnetic core comprises a first outer magnetic core, a second outer magnetic core and a winding unit; the first outer magnetic core and the second outer magnetic core are arranged opposite to each other along a first direction, the winding unit is arranged between the first outer magnetic core and the second outer magnetic core, and the coil winding is arranged around the winding unit; The winding unit includes a magnetic core column and at least two air gaps distributed along a first direction, wherein the axis of the magnetic core column is parallel to the first direction; the at least two air gaps include an air gap and at least one solid air gap; the magnetic induction intensity of the solid air gap is greater than the magnetic induction intensity of the magnetic core column; The center of the solid air gap has a hollow area that penetrates the solid air gap along the first direction, so that the solid air gap is a closed ring. The material of the solid air gap is a magnetic material.

2. The inductor according to claim 1, wherein: The magnetic core center column is fixedly connected to the first outer magnetic core, and the air gap is formed between the magnetic core center column and the second outer magnetic core; or, the magnetic core center column is fixedly connected to the second outer magnetic core, and the air gap is formed between the magnetic core center column and the first outer magnetic core.

3. The inductor according to claim 1, wherein: The magnetic core middle column includes a first sub-column and a second sub-column, the first sub-column is fixedly connected to the first outer magnetic core, and the second sub-column is fixedly connected to the second outer magnetic core; The air gap is formed between the first sub-column and the second sub-column.

4. The inductor according to claim 1, wherein: The air gap is adjacent to the solid gap.

5. The inductor according to claim 1, wherein: The magnetic core center column includes a plurality of inner magnetic cores, and the air gap and the solid gap are respectively arranged on two sides of one of the inner magnetic cores along a first direction.

6. The inductor according to claim 1, wherein: A radial dimension of the solid air gap perpendicular to the first direction is smaller than a radial dimension of the magnetic core center column perpendicular to the first direction.

7. The inductor according to any one of claims 1 to 6, characterized in that: The first outer magnetic core includes a first base and two first side columns, wherein the two first side columns are fixed to the first base and extend to the second outer magnetic core; The second outer magnetic core includes a second base and two second side columns, wherein the two second side columns are fixed to the second base and extend from the first outer magnetic core; The two first side columns and the two second side columns are matched and connected in a one-to-one correspondence.

8. A power factor correction circuit, characterized in that: The device comprises a capacitor, a metal oxide semiconductor field effect transistor switch, a diode and an inductor as claimed in any one of claims 1 to 7.

9. A power supply system, characterized in that: It includes an AC-DC conversion circuit, a DC transformer circuit, and a control circuit; the AC-DC conversion circuit includes a rectifier circuit and the power factor correction circuit as claimed in claim 8.

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