Oscillation suppression circuit and power supply

Abstract

The present invention discloses an oscillation suppression circuit and a power supply, wherein the suppression circuit comprises: the first end and the second end of the primary side of the transformer are respectively connected to the midpoints of the two bridge arms of the single-phase bridge circuit, the first end and the second end of the secondary side of the transformer are respectively connected to the first end and the second end of the filter circuit; the second end and the third end of the filter circuit are respectively connected to the two ends of the load; when the single-phase bridge circuit is lightly loaded, the inter-turn capacitance of the transformer and the filter circuit form a C‑L‑C filter network; when the single-phase bridge circuit is fully loaded, the inter-turn capacitance of the transformer and the filter circuit form a C‑C filter network. Based on the above structure, the oscillation suppression circuit proposed in the embodiment of the present invention can absorb oscillation energy under light load conditions, and does not affect the operation of the converter under full load conditions. At the same time, the circuit structure is simple and easy to implement.

Description

Technical Field

[0001] The invention relates to the field of power electronics, and in particular to an oscillation suppression circuit and a power supply. Background Art

[0002] SiC MOSFET can greatly improve the efficiency and power density of the converter, and has good application prospects in high frequency, high temperature, high voltage and other fields. However, due to its faster switching speed, it causes more serious voltage oscillation. If the oscillating voltage spike is not limited, it can easily cause damage to the SiC MOSFET device.

[0003] In converter applications based on SiC MOSFET devices, due to the high switching speed of SiC MOSFET, when the converter is lightly loaded, the load current is small, and the high-frequency oscillation is more obvious in the inverter circuit, which can easily cause more serious spike voltages, thereby reducing the reliability of the device. It is necessary to add an oscillation absorption circuit in the converter circuit to suppress the circuit oscillation and improve the operating reliability of the converter.

[0004] The purpose of oscillation suppression is to absorb oscillation energy by adding auxiliary devices or circuits, thereby reducing the peak voltage and achieving the effect of suppressing oscillation. However, the addition of auxiliary devices or circuits to the converter will further increase the loss and reduce the overall efficiency of the converter. Therefore, when adding an oscillation suppression circuit, it is necessary to absorb the oscillation energy without affecting the operation of the converter. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the prior art that suppressing the oscillation of the converter by adding auxiliary devices or loops will increase the loss and reduce the overall efficiency of the converter, thereby providing an oscillation suppression circuit and power supply.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides an oscillation suppression circuit, comprising: a transformer and a filter circuit, wherein the first end and the second end of the primary side of the transformer are respectively connected to the midpoints of the two bridge arms of a single-phase bridge circuit, and the first end and the second end of the secondary side of the transformer are respectively connected to the first end and the second end of the filter circuit; the second end and the third end of the filter circuit are respectively connected to the two ends of the load; when the single-phase bridge circuit is lightly loaded, the turn-to-turn capacitance of the transformer and the filter circuit constitute a CLC filter network; when the single-phase bridge circuit is fully loaded, the turn-to-turn capacitance of the transformer and the filter circuit constitute a CC filter network.

[0008] In one embodiment, the filtering circuit includes: a saturated inductor and a capacitor, wherein the first end of the saturated inductor is connected to the first end of the secondary side of the transformer, the second end of the saturated inductor is respectively connected to the first end of the capacitor and the first end of the load, and the second end of the capacitor is respectively connected to the second end of the secondary side of the transformer and the second end of the load.

[0009] In a second aspect, an embodiment of the present invention provides a power supply, based on the oscillation suppression circuit of the first aspect, the power supply includes: a DC power supply, at least one oscillation suppression circuit and at least one inverter, wherein two ends of the DC power supply are connected to two ends of the DC side of each inverter; two input ends of each oscillation suppression circuit are respectively connected to the midpoint of a bridge arm of an inverter, and two output ends of each oscillation suppression circuit are respectively connected to two ends of a load; when there are multiple inverters, the second output end of each oscillation suppression circuit is also connected to one point to form a neutral point.

[0010] In one embodiment, the inverter is a single-phase full-bridge circuit or a single-phase half-bridge circuit.

[0011] In one embodiment, the single-phase full-bridge circuit includes: a plurality of SiC MOSFETs, wherein every two SiC MOSFETs are connected in series to form a bridge arm.

[0012] In one embodiment, a single-phase half-bridge circuit includes: a plurality of SiC MOSFETs and a plurality of capacitors, wherein every two SiC MOSFETs are connected in series to form a bridge arm, and every two capacitors are connected in series to form a bridge arm.

[0013] The technical solution of the present invention has the following advantages:

[0014] The oscillation suppression circuit provided by the present invention has the first and second ends of the primary side of the transformer connected to the midpoints of the two bridge arms of the single-phase bridge circuit respectively, and the first and second ends of the secondary side of the transformer connected to the first and second ends of the filter circuit respectively; the second and third ends of the filter circuit are connected to the two ends of the load respectively; when the single-phase bridge circuit is lightly loaded, the inter-turn capacitance of the transformer and the filter circuit form a CLC filter network; when the single-phase bridge circuit is fully loaded, the inter-turn capacitance of the transformer and the filter circuit form a CC filter network. Based on the above structure, the oscillation suppression circuit proposed in the embodiment of the present invention can absorb oscillation energy under light load conditions, and does not affect the operation of the converter under full load conditions. At the same time, the circuit structure is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] FIG. 1( a ) and FIG. 1( b ) are respectively composition diagrams of a specific example of an oscillation suppression circuit provided by an embodiment of the present invention;

[0017] FIG. 2( a ) and FIG. 2( b ) are respectively composition diagrams of another specific example of the oscillation suppression circuit provided by an embodiment of the present invention;

[0018] FIG. 3( a ) and FIG. 3( b ) are respectively composition diagrams of a specific example of a power supply provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Example 1

[0024] The embodiment of the present invention provides an oscillation suppression circuit, as shown in FIG1(a) and FIG1(b), comprising: a transformer 1, a filter circuit 2, wherein the first end and the second end of the primary side of the transformer 1 are respectively connected to the midpoints of the two bridge arms of the single-phase bridge circuit, the first end and the second end of the secondary side of the transformer 1 are respectively connected to the first end and the second end of the filter circuit 2; the second end and the third end of the filter circuit 2 are respectively connected to the two ends of the load. The single-phase bridge circuit of the embodiment of the present invention can be a full-bridge circuit or a half-bridge circuit, which is not limited here.

[0025] Specifically, when the single-phase bridge circuit is lightly loaded, the inter-turn capacitance of the transformer 1 and the filter circuit 2 form a CLC filter network, and the filter network is determined by the structure of the filter circuit 2, which is not limited here; when the single-phase bridge circuit is fully loaded, the saturated components inside the filter circuit 2 have no effect on the converter, so the inter-turn capacitance of the transformer 1 and the filter circuit 2 form a CC filter network. So far, based on the above structure, the oscillation suppression circuit proposed in the embodiment of the present invention can absorb oscillation energy under light load conditions and not affect the operation of the converter under full load conditions. At the same time, the circuit structure is simple and easy to implement.

[0026] In a specific embodiment, as shown in Figures 2(a) and 2(b), the filter circuit 2 includes: a saturated inductor L and a capacitor C2, wherein a first end of the saturated inductor L is connected to a first end of a secondary side of the transformer 1, a second end of the saturated inductor L is respectively connected to a first end of the capacitor C2 and a first end of a load, and a second end of the capacitor C2 is respectively connected to a second end of a secondary side of the transformer 1 and a second end of the load, wherein in Figures 2(a) and 2(b), Lr is a transformer leakage inductance, C1 is a turn-to-turn capacitance of the transformer 1, and T is a transformer.

[0027] Example 2

[0028] The embodiment of the present invention provides a power supply, based on the oscillation suppression circuit of embodiment 1, as shown in FIG3(a) and FIG3(b), the power supply includes: a DC power supply 1, at least one oscillation suppression circuit 2 and at least one inverter 3, wherein the two ends of the DC power supply 1 are connected to the two ends of the DC side of each inverter 3; the two input ends of each oscillation suppression circuit 2 are respectively connected to the midpoint of the bridge arm of an inverter 3, specifically as shown in FIG2(a) and FIG2(b), the two output ends of each oscillation suppression circuit 2 are respectively connected to the two ends of a load. As shown in FIG3(b), when there are multiple inverters 3, the second output end of each oscillation suppression circuit 2 is also connected to a point to form a neutral point.

[0029] Specifically, when there is one inverter 3, the power supply of the embodiment of the present invention outputs single-phase AC power, and when there are three inverters 3, the power supply of the embodiment of the present invention outputs three-phase AC power, and the three inverters 3 are isolated from each other.

[0030] In a specific embodiment, the inverter 3 is a single-phase full-bridge circuit or a single-phase half-bridge circuit.

[0031] As shown in FIG. 2( a ), the single-phase full-bridge circuit includes: a plurality of SiC MOSFETs, where every two SiC MOSFETs are connected in series to form a bridge arm.

[0032] As shown in FIG. 2( b ), the single-phase half-bridge circuit includes: a plurality of SiC MOSFETs and a plurality of capacitors, wherein every two SiC MOSFETs are connected in series to form a bridge arm, and every two capacitors are connected in series to form a bridge arm.

[0033] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. An oscillation suppression circuit, characterized in that: include: Transformer, filter circuit, among which, The first end and the second end of the primary side of the transformer are respectively connected to the midpoints of the two bridge arms of the single-phase bridge circuit, and the first end and the second end of the secondary side of the transformer are respectively connected to the first end and the second end of the filter circuit; The second end and the third end of the filter circuit are connected to two ends of the load respectively; When the single-phase bridge circuit is lightly loaded, the turn-to-turn capacitance of the transformer and the filter circuit form a CLC filter network; when the single-phase bridge circuit is fully loaded, the turn-to-turn capacitance of the transformer and the filter circuit form a CC filter network; The filter circuit includes: a saturated inductor and a capacitor, wherein: The first end of the saturated inductor is connected to the first end of the secondary side of the transformer, the second end of the saturated inductor is connected to the first end of the capacitor and the first end of the load respectively, and the second end of the capacitor is connected to the second end of the secondary side of the transformer and the second end of the load respectively.

2. A power supply, characterized in that: Based on the oscillation suppression circuit according to claim 1, the power supply comprises: a DC power supply, at least one oscillation suppression circuit and at least one inverter, wherein: Two ends of the DC power supply are connected to two ends of the DC side of each inverter; The two input ends of each oscillation suppression circuit are respectively connected to the midpoint of a bridge arm of the inverter, and the two output ends of each oscillation suppression circuit are respectively connected to the two ends of a load; When there are multiple inverters, the second output end of each oscillation suppression circuit is further connected to one point to form a neutral point.

3. The power supply according to claim 2, characterized in that: The inverter is a single-phase full-bridge circuit or a single-phase half-bridge circuit.

4. The power supply according to claim 3, characterized in that: The single-phase full-bridge circuit comprises: Multiple SiC MOSFETs, every two SiC MOSFETs are connected in series to form a bridge arm.

5. The power supply according to claim 3, characterized in that: The single-phase half-bridge circuit comprises: Multiple SiC MOSFETs and multiple capacitors, every two SiC MOSFETs are connected in series to form a bridge arm, and every two capacitors are connected in series to form a bridge arm.

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