CN113380492B - AC-DC coupled common-mode inductors for DC inverter power supply systems - Google Patents

Abstract

The present invention proposes an AC-DC coupled common-mode inductor for a DC inverter power supply system, comprising a DC-side common-mode inductor (1) and an AC-side common-mode inductor (2); the DC-side common-mode inductor (1) includes An annular first magnetic core (11) and two windings (12) in the same direction wound on the first magnetic core (11); the AC side common mode inductor (2) includes an annular second magnetic core ( 21) and two or three AC phase lines (22) passing through the window of the second magnetic core (21). In the present invention, the second magnetic core (21) is supported and nested inside the window of the first magnetic core (11) through the insulating material (4), and the coupling of the common-mode inductance on both sides of the inverter AC and DC is realized, thereby ensuring the On the premise of effectively suppressing the common-mode current on both sides of the AC and DC in the DC inverter power supply system, the volume of the common-mode inductor can be miniaturized.

Description

AC-DC coupled common-mode inductors for DC inverter power supply systems

technical field

The invention belongs to the technical field of power electronics and relates to an AC-DC coupled common-mode inductor, which is suitable for a DC inverter power supply system.

Background technique

A DC inverter power supply system usually consists of a DC power supply, an inverter and a load; when the system is in normal operation, the inverter converts DC power into AC power for the load through PWM pulse width modulation technology; although this modulation technology can be used in many Reduce the loss of the system to a large extent and reduce the demand for heat dissipation of the system, but the disadvantage is that this method will make the switching device in the inverter always work in a high-frequency switching state, and its rapid turn-on and turn-off will A steep pulse with a very high amplitude is formed, resulting in serious electromagnetic interference, which is the main source of interference in the DC inverter power supply system; this electromagnetic interference generated by the inverter will seriously affect the normal operation of the system, so looking for DC The solution to the electromagnetic interference problem in the inverter power supply system has become a top priority for its development. In addition, due to the many application platforms of the DC inverter power supply system, such as electric drive systems and small switching power supplies, in order to achieve better economy and versatility, strict requirements are placed on the size of the system. Therefore, while solving the electromagnetic interference problem of the system, the miniaturization and integration goals of the system must be considered at the same time. This is the only way to realize the commercial use of the DC inverter power supply system.

Setting common-mode inductors in the DC inverter power supply system can reduce the common-mode current and form a high-impedance path for multiple harmonics to suppress electromagnetic interference; common-mode inductors with excellent performance are ideal for electric drive systems, etc. The necessary guarantee for the operation of the DC inverter power supply system platform. Reasonable design of filter common-mode inductors is very important to ensure the normal operation of the system. For traditional filter common-mode inductors, a single common-mode inductor can only be connected in series on the AC side or DC side of the inverter alone. However, in the relevant standards for DC inverter power supply systems, the assessment of noise level Taking into account both sides of the AC and DC, so if you want to reduce the noise on both sides of the DC inverter power supply system at the same time, you must increase the number of common mode inductors, which will not only greatly increase the volume of the system, but also reduce the DC inverter power supply system. The economy and versatility of the variable power supply system are unacceptable for many modern power electronic systems.

In order to filter out the high-frequency noise on both the AC and DC sides of the inverter at the same time, scholars from various countries have carried out theoretical and applied research work on the three aspects of the system's interference source, propagation path, and sensitive equipment, and have achieved certain results. Achievement. For example, the application publication number is CN108039815A, and the patent application titled "An Electromagnetic Interference Circuit and Its Operation Method" discloses a circuit for suppressing the common-mode current on both sides of the inverter; the invention is on the DC bus of the inverter A common-mode inductor on the DC side is formed by a magnetic ring, which is used to suppress the common-mode current on the DC side of the inverter; at the same time, a common-mode inductor and a magnetic ring are connected in series on the AC side to suppress the common-mode current on the AC side of the inverter; although the invention can Effectively suppress the common-mode current on both sides of the inverter at the same time, but it only achieves this goal by increasing the number of common-mode inductors, which will greatly increase the volume of the DC inverter power supply system and seriously damage the economy of the system It is not conducive to the practical application of the system.

Contents of the invention

The purpose of the present invention is to provide an AC-DC coupled common-mode inductor for the DC inverter power supply system to ensure effective control of the common-mode current on the AC and DC sides of the DC inverter power supply system. Under the premise of suppression, the miniaturization of the common mode inductor is realized.

In order to achieve the above purpose, the technical solution adopted by the present invention includes a common mode inductor 1 on the DC side and a common mode inductor 2 on the AC side:

The DC-side common mode inductor 1 includes a ring-shaped first magnetic core 11 and two windings 12 with opposite winding directions wound on the first magnetic core 11, wherein the two ends of one winding are respectively used to connect the inverter The positive pole of the inverter and the positive pole of the DC power supply, and the two ends of the other winding are respectively used to connect the negative pole of the inverter and the negative pole of the DC power supply. The common mode inductor 1 on the DC side is used to reduce the The common mode current;

The common mode inductor 2 on the AC side includes an annular second magnetic core 21 and two or three AC phase lines 22 passing through the window of the second magnetic core 21, and the window of the second magnetic core 21 is provided with a support The insulating material 3 isolating the adjacent AC phase lines and the AC phase lines and the second magnetic core 21, the two ends of the two or three AC phase lines 22 are used to connect the output end of the inverter and the load input end, the AC The side common mode inductor 2 is used to reduce the common mode current of the AC side in the DC inverter power supply system;

The second magnetic core 21 is nested in the window of the first magnetic core 11, and the two magnetic cores are supported by an insulating material 4 to realize the connection between the common mode inductor 2 on the AC side and the common mode inductor 1 on the DC side. Coupling between.

In the aforementioned AC-DC coupled common-mode inductor for DC inverter power supply systems, the number of turns of the two windings 12 wound on the first magnetic core 11 is the same, and the two windings 12 are about the first The center normals of the magnetic cores 11 differ by 180°.

In the aforementioned AC-DC coupled common-mode inductor for a DC inverter power supply system, the central normal of the first magnetic core 11 coincides with the central normal of the second magnetic core 21, and the first magnetic core 11 and the The window sections of the second magnetic core 21 are coplanar.

In the aforementioned AC-DC coupled common-mode inductor used in a DC inverter power supply system, the AC phase line 22 that runs through the window of the second magnetic core 21 is rotationally symmetrical about the center normal of the second magnetic core 21. When the AC phase line When there are two wires, the two AC phase wires have a phase difference of 180°; when there are three AC phase wires, the three AC phase wires have a phase difference of 120°.

Compared with the prior art, the present invention has the following advantages:

1. In the present invention, the annular magnetic core of the common-mode inductor on the AC side is nested inside the window of the annular magnetic core of the common-mode inductor on the DC side through an insulating support material, and through the coupling of the common-mode inductor on the AC side and the common-mode inductor on the DC side, The inductance of the common-mode inductors on both sides of the AC and DC is increased, avoiding the defect of increasing the inductance by increasing the number of common-mode inductors in the prior art. Compared with the prior art, it can effectively suppress the system common-mode Under the premise of the current, the volume of the common mode inductor is effectively reduced, and the miniaturization is realized.

2. The present invention nests the first magnetic core inside the second magnetic core, which improves the window utilization of the first magnetic core and reduces the volume of the common-mode inductor, thereby reducing the manufacturing cost of the common-mode inductor and improving its economy and versatility.

Description of drawings

Fig. 1 is the structural representation of the specific embodiment of the present invention;

Fig. 2 is a connection circuit diagram of the present invention and related components of the DC inverter power supply system.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to FIG. 1 , the present invention includes a DC side common mode inductor 1 and an AC side common mode inductor 2 .

The DC-side common mode inductor 1 includes a ring-shaped first magnetic core 11 and two windings 12 wound on the first magnetic core 11; in order to facilitate the combination of two common mode inductors, the first The magnetic core 11 adopts a circular magnetic core with a circular cross section; in order to make the common mode inductor have sufficient anti-saturation capability and filtering capability, the first magnetic core 11 in this embodiment has an initial magnetic permeability of 60,000 and a saturation magnetic induction of The nanocrystalline magnetic core of 1.2T; The two windings 12 wound on the first magnetic core 11, in order to make the common mode inductance can bear larger current, the winding material selects the copper wire with large current-carrying capacity for use; In order to control The magnetic circuit length of the magnetic core group is within a reasonable range, and at the same time, the inductance of the common mode inductor on the DC side is increased as much as possible. In this embodiment, the number of 12 turns of the positive and negative windings of the common mode inductor on the DC side is selected as 8 turns ; In addition, the winding directions of the two windings are opposite, and the winding positions of the two windings are 180° different from the center normal of the first magnetic core, which can ensure the symmetry of the common mode inductance of the DC side and prevent the positive and negative bus inductance from The differential common-mode conversion caused by the difference makes the common-mode inductor have the best filtering performance.

The common-mode inductor 2 on the AC side includes an annular second magnetic core 21 and two or three AC phase wires 22 running through the window of the second magnetic core; in this embodiment, three AC phase wires are used; in order to improve The anti-saturation and filtering capabilities of the common-mode inductor on the AC side also have a large current-carrying capacity. The second core 21 of the common-mode inductor on the AC side also uses a common nanocrystalline core, and the AC phase line also uses a current-carrying In addition, in common-mode inductors with multiple windings, a problem that needs special attention is to achieve symmetry in the spatial positions of multiple windings, which is especially important for achieving the optimal performance of common-mode inductor filtering important. Therefore, when the number of AC phase lines is three, the three AC phase lines should be rotationally symmetrical about the central normal of the second magnetic core, and the difference between them is 120°. In order to improve the insulation performance, disc-shaped insulating rubber is used to fill and fix between the three AC phase wires and between the AC phase wire and the second magnetic core 21;

The second magnetic core 21 of the AC-side common-mode inductor 2 is supported and nested inside the window of the first magnetic core 11 of the DC-side common-mode inductor 1 through the insulating support material 4; considering the insulation requirements of the common-mode inductors on both sides and Fixed requirements, in this embodiment, the insulating support material 4 is an insulating rubber material with good insulation; at the same time, in order to achieve a strong coupling between the common mode inductor 1 on the DC side and the common mode inductor 2 on the AC side, to obtain a larger inductance, In this embodiment, the central normals of the first magnetic core 11 and the second magnetic core 21 coincide, and the window sections of the two magnetic cores are coplanar.

Referring to Figure 2, the two ends of one winding of the DC side common mode inductor 1 are respectively used to connect the positive pole of the inverter to the positive pole of the DC power supply, and the two ends of the other winding are respectively used to connect the negative pole of the inverter to the negative pole of the DC power supply The common mode inductor 1 on the DC side is used to reduce the common mode current on the DC side in the DC inverter power supply system; the two ends of the three AC phase lines 22 of the common mode inductor 2 on the AC side are respectively used for the three-phase output of the inverter The terminal is connected to the three-phase input terminal of the load; the common mode inductor on the AC side is used to reduce the common mode current on the AC side in the DC inverter power supply system.

The working principle of the present invention is:

The invention provides an AC-DC coupled common-mode inductor capable of effectively suppressing the common-mode current on both AC and DC sides of an inverter in a DC inverter power supply system. Utilizing the principle that different inductances can increase the inductance through the mutual inductance effect, the ring core of the common mode inductor on the AC side is nested inside the ring core window of the common mode inductor on the DC side to form a common mode inductor on both sides The coupling increases the inductance of the common-mode inductors on both sides without increasing the volume of the common-mode inductor, and improves the filtering capability of the common-mode inductor. Among them, the common-mode inductor on the DC side is connected to the positive and negative busbars of the inverter, forming a high-impedance path for the high-frequency common-mode current that flows through; the common-mode inductor on the AC side is connected to the AC phase line of the inverter, and the The high-frequency common-mode current forms a high-impedance path, thereby reducing the common-mode current in the system and preventing common-mode noise from causing damage to sensitive equipment in the system.

The above description is only an example of the present invention, and does not constitute any limitation to the present invention. Obviously, for those skilled in the art, after understanding the content and principles of the present invention, it is possible without departing from the principles and structures of the present invention. Various amendments and changes in form and details are made, but these amendments and changes based on the idea of the present invention are still within the protection scope of the claims of the present invention.

Claims (4)

1. The utility model provides an alternating current-direct current manifold type common mode inductor for direct current contravariant power supply system which characterized in that: the inductor comprises a common mode inductor (1) at a direct current side and a common mode inductor (2) at an alternating current side;

the direct-current-side common-mode inductor (1) comprises an annular first magnetic core (11) and two windings (12) wound on the first magnetic core (11) and having opposite winding directions, wherein two ends of one winding are respectively used for connecting the positive electrode of an inverter and the positive electrode of a DC power supply, two ends of the other winding are respectively used for connecting the negative electrode of the inverter and the negative electrode of the DC power supply, and the direct-current-side common-mode inductor (1) is used for reducing common-mode current on the direct current side in a direct-current inversion power supply system;

the alternating current side common mode inductor (2) comprises an annular second magnetic core (21) and two or three alternating current phase lines (22) penetrating through a window of the second magnetic core (21), an insulating material (3) used for supporting and isolating adjacent alternating current phase lines and the second magnetic core (21) is arranged in the window of the second magnetic core (21), two ends of the two or three alternating current phase lines (22) are used for connecting an output end and a load input end of an inverter, and the alternating current side common mode inductor (2) is used for reducing common mode current on the alternating current side in a direct current inversion power supply system;

the second magnetic core (21) is nested in the window of the first magnetic core (11), and the two magnetic cores are supported through an insulating material (4) and used for realizing coupling between the common mode inductor (2) on the alternating current side and the common mode inductor (1) on the direct current side.

2. The common mode inductor of ac-dc coupling for dc-to-ac inverter supply system according to claim 1, wherein the first core (11) has two windings (12) wound thereon with the same number of turns, and the two windings (12) are different from each other by 180 ° with respect to the center normal of the first core (11).

3. The common mode inductor of claim 1, wherein the center normal of the first magnetic core (11) coincides with the center normal of the second magnetic core (21), and the window sections of the first magnetic core (11) and the second magnetic core (21) are coplanar.

4. The AC-DC coupled common mode inductor for the DC-DC inverter power supply system according to claim 1, wherein the AC phase lines (22) passing through the window of the second magnetic core (21) are rotationally symmetric with respect to the center normal of the second magnetic core (21), and when the number of the AC phase lines is two, the two AC phase lines are 180 ° different, and when the number of the AC phase lines is three, the three AC phase lines are 120 ° different.

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