Harmonic suppression circuit and system

Abstract

The utility model discloses a harmonic suppression circuit and system, and relates to the field of harmonic suppression, the circuit is provided with a first differential mode filter module, a second differential mode filter module, a third differential mode filter module, a common mode inductor, a first common mode filter module, a second common mode filter module and a third common mode filter module, the differential-mode filtering modules, the common-mode filtering modules and the inductor are used for filtering so as to filter out higher harmonics and electromagnetic interference in electric energy, the three windings of the common-mode inductor are correspondingly connected with the differential-mode filtering modules and the common-mode filtering modules respectively, and the lengths and the impedances of the three windings are equal, so that the three windings cannot be wound in a lap mode, and the power consumption is reduced. The differential-mode filter module is simple in winding and cannot cause current imbalance, in addition, the lengths of the three windings are equal, so that the lengths of the differential-mode filter modules are equal after the differential-mode filter modules are connected to the windings, a loop is short, parasitic inductance and capacitance in a circuit are reduced, and loss is reduced.

Description

Technical Field

[0001] The utility model relates to the field of harmonic suppression, in particular to a harmonic suppression circuit and system. Background Art

[0002] With the rapid development of the power electronics industry, various high-power power converters are increasingly used in the field of new energy. The principle is to obtain the required waveform, frequency and step-up and step-down conversion based on high-speed switching device modulation. Since the switching frequency is usually from several thousand hertz to several megahertz, it will bring high-order harmonics and electromagnetic interference problems. In order to suppress high-order harmonics and electromagnetic interference, a circuit that suppresses differential and common-mode harmonic interference is generally used.

[0003] In the prior art, the inductor in the circuit for suppressing differential and common mode harmonic interference uses a toroidal magnetic core and an enameled wire to wind the coil. When the current is large, multiple strands of enameled wire are connected in parallel to increase the cross-sectional area to increase the current carrying capacity. The first disadvantage is that the winding is difficult and the production takes a long time. The second disadvantage is that when multiple strands are connected in parallel, overlapping windings will occur, resulting in different lengths of each line, different impedances, and unbalanced current. Utility Model Content

[0004] The utility model aims to provide a harmonic suppression circuit and system, in which three windings of a common mode inductor in the circuit are respectively connected to each differential mode filter module and the common mode filter module, and the lengths and impedances of the three windings are equal, so the three windings will not be overlapped, the winding is simple, and current imbalance will not be caused. In addition, because the lengths of the three windings are equal, the lengths of each differential mode filter module after being connected to the windings are equal, and the loop is shorter, thereby reducing the parasitic inductance and capacitance in the circuit and reducing the loss.

[0005] In order to solve the above technical problems, the utility model provides a harmonic suppression circuit, including: a first differential mode filter module, a second differential mode filter module, a third differential mode filter module, a common mode inductor, a first common mode filter module, a second common mode filter module and a third common mode filter module;

[0006] The first end of the first differential mode filter module is respectively connected to the first phase power supply of the three-phase power supply, and the second end is connected to the second phase power supply of the three-phase power supply;

[0007] The first end of the second differential mode filter module is respectively connected to the first phase power supply of the three-phase power supply, and the second end is connected to the third phase power supply of the three-phase power supply;

[0008] The first end of the third differential mode filter module is respectively connected to the second phase power supply of the three-phase power supply, and the second end is connected to the third phase power supply of the three-phase power supply;

[0009] The first end of the first winding of the common-mode inductor is connected to the first-phase power supply, the second end of the first winding is respectively connected to the first end of the first common-mode filter module and the first end of the power converter, the first end of the second winding is connected to the second-phase power supply, the second end of the second winding is respectively connected to the first end of the second common-mode filter module and the first end of the power converter, the first end of the third winding is connected to the third-phase power supply, the second end of the third winding is respectively connected to the first end of the third common-mode filter module and the third end of the power converter, and the lengths and impedances of the first winding, the second winding and the third winding are equal;

[0010] The second end of the first common mode filtering module is grounded;

[0011] The second end of the second common mode filtering module is grounded;

[0012] The second end of the third common-mode filtering module is grounded.

[0013] Optionally, the first differential mode filtering module includes: a first capacitor, a first resistor, a second capacitor and a second resistor;

[0014] The first ends of the first capacitors are respectively connected to the first phase power supplies, and the second ends are respectively connected to the first ends of the second capacitors and the first ends of the second resistors;

[0015] The second end of the second capacitor is connected to the second phase power supply;

[0016] The first ends of the first resistors are respectively connected to the first phase power supplies, and the second ends are respectively connected to the first ends of the second capacitors and the first ends of the second resistors;

[0017] The second end of the second resistor is connected to the second phase power supply;

[0018] Correspondingly, the second differential mode filtering module includes: the first capacitor, the first resistor, a third capacitor and a third resistor;

[0019] The first ends of the first capacitors are respectively connected to the first phase power supply, and the second ends are respectively connected to the first ends of the third capacitors and the first ends of the third resistors;

[0020] The second end of the third capacitor is connected to the third phase power supply;

[0021] The first ends of the first resistors are respectively connected to the first phase power supply, and the second ends are respectively connected to the first end of the third capacitor and the first end of the third resistor;

[0022] The second end of the third resistor is connected to the third phase power supply;

[0023] Correspondingly, the third differential mode filtering module includes: the second capacitor, the second resistor, the third capacitor and the third resistor;

[0024] The first ends of the second capacitors are respectively connected to the second phase power supply, and the second ends are respectively connected to the first ends of the third capacitors and the first ends of the third resistors;

[0025] The second end of the third capacitor is connected to the third phase power supply;

[0026] The first ends of the second resistors are respectively connected to the second phase power supply, and the second ends are respectively connected to the first ends of the third capacitors and the first ends of the third resistors;

[0027] The second end of the third resistor is connected to the third phase power supply.

[0028] Optionally, it further includes: a fourth differential mode filtering module, a fifth differential mode filtering module and a sixth differential mode filtering module;

[0029] The first end of the fourth differential mode filter module is connected to the first winding, and the second end is connected to the second winding;

[0030] The first end of the fifth differential mode filter module is connected to the first winding, and the second end is connected to the third winding;

[0031] The first end of the sixth differential mode filter module is connected to the second winding, and the second end is connected to the third winding. The first winding, the second winding and the third winding are evenly arranged around the magnetic core of the common mode inductor.

[0032] Optionally, the fourth differential mode filtering module includes: a fourth capacitor and a fifth capacitor;

[0033] A first end of the fourth capacitor is connected to the first winding, and a second end of the fourth capacitor is connected to the first end of the fifth capacitor;

[0034] The second end of the fifth capacitor is connected to the second winding;

[0035] Correspondingly, the fifth differential mode filtering module includes: the fourth capacitor and the sixth capacitor;

[0036] A first end of the fourth capacitor is connected to the first winding, and a second end of the fourth capacitor is connected to the first end of the sixth capacitor;

[0037] The second end of the sixth capacitor is connected to the third winding;

[0038] Correspondingly, the sixth differential mode filtering module includes: the fifth capacitor and the sixth capacitor;

[0039] The first end of the fifth capacitor is connected to the second winding, and the second end is connected to the first end of the sixth capacitor;

[0040] The second end of the sixth capacitor is connected to the third winding.

[0041] Optionally, the first common-mode filtering module is a seventh capacitor, a first end of the seventh capacitor is connected to the first winding and the first end of the electric energy converter, and a second end is grounded;

[0042] Correspondingly, the second common-mode filtering module is an eighth capacitor, a first end of the eighth capacitor is connected to the second winding and the second end of the electric energy converter, and a second end is grounded;

[0043] Correspondingly, the third common-mode filtering module is a ninth capacitor, a first end of the ninth capacitor is connected to the third winding and the third end of the electric energy converter, and a second end is grounded.

[0044] In order to solve the above technical problems, the utility model provides a harmonic suppression system, comprising: an electric energy converter and the harmonic suppression circuit as described above, wherein the harmonic suppression circuit is connected to the electric energy converter.

[0045] Optionally, the electric energy converter comprises: a rectifier module, a seventh differential mode filter module, an inverter module, and a transformer module;

[0046] The rectifier module is connected to the first winding, the second winding and the third winding respectively, and is used to convert the first AC power transmitted by the common mode inductor into corresponding DC power;

[0047] The seventh differential mode filter module is connected to the rectifier module and is used to perform corresponding filtering on the DC power;

[0048] The inverter module is connected to the rectifier module and is used to convert the filtered DC power into corresponding second AC power;

[0049] The transformer module is connected to the inverter module and the power grid respectively, and is used to convert the first voltage of the second AC power transmitted by the inverter module into a second voltage required by the power grid, and transmit the converted second AC power to the power grid.

[0050] Optionally, the seventh differential mode filtering module includes: a first magnetic core inductor and a tenth capacitor;

[0051] The first end of the first magnetic core inductor is respectively connected to the rectifier module and the inverter module;

[0052] The first end of the tenth capacitor is connected to the second end of the first magnetic core inductor, and the second end is connected to the rectifier module and the inverter module respectively.

[0053] Optionally, the voltage transformation module includes: an eleventh capacitor, a transformer, a unidirectional conduction module and an eighth differential mode filtering module;

[0054] The first end of the eleventh capacitor is connected to the inverter module, and the second end is connected to the first end of the primary winding of the transformer, and is used to filter the second AC power output by the inverter module;

[0055] The second end of the primary winding of the transformer is connected to the inverter module, and the secondary winding is connected to the eighth differential mode filter module, for converting the first voltage of the second AC electric energy after filtering into the second voltage;

[0056] The eighth differential mode filtering module is connected to the unidirectional conducting module, and is used for filtering the second alternating current power of the second voltage;

[0057] The unidirectional conduction module is connected to the power grid, and is used to transmit the second AC power of the second voltage after filtering to the power grid.

[0058] Optionally, the unidirectional conduction module includes: a first diode and a second diode;

[0059] The anode of the first diode is connected to the first end of the secondary winding of the transformer, and the cathode is connected to the eighth differential mode filter module;

[0060] The anode of the second diode is connected to the second end of the secondary winding of the transformer, and the cathode is connected to the cathode of the first diode and the eighth differential mode filter module respectively.

[0061] Optionally, the eighth differential mode filtering module includes: a second magnetic core inductor and a twelfth capacitor;

[0062] A first end of the second magnetic core inductor is connected to the unidirectional conduction module, and a second end thereof is respectively connected to a first end of the twelfth capacitor and the power grid;

[0063] The second end of the twelfth capacitor is connected to the unidirectional conduction module and the power grid respectively.

[0064] The utility model aims to provide a harmonic suppression circuit and system, wherein a first differential mode filter module, a second differential mode filter module, a third differential mode filter module, a common mode inductor, a first common mode filter module, a second common mode filter module and a third common mode filter module are arranged in the circuit, wherein each differential mode filter module, the common mode filter module and the inductor are used for filtering to filter out high-order harmonics and electromagnetic interference in electric energy, and the three windings of the common mode inductor in the present scheme are respectively connected to each differential mode filter module and the common mode filter module, and the lengths and impedances of the three windings are equal, so the three windings will not be overlapped, the winding is simple, and will not cause current imbalance, in addition, because the lengths of the three windings are equal, the lengths of each differential mode filter module after being connected to the windings are equal, and the loop is short, thereby reducing the parasitic inductance and capacitance in the circuit and reducing the loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0066] Figure 1 A schematic diagram of the structure of a harmonic suppression circuit provided by the utility model;

[0067] Figure 2 A schematic diagram of the structure of another harmonic suppression circuit provided by the utility model;

[0068] Figure 3A A top view schematic diagram of a common mode inductor provided by the utility model;

[0069] Figure 3B A schematic top view of a common mode inductor provided by the utility model;

[0070] Figure 3C A schematic diagram of the side structure of a common mode inductor provided by the utility model;

[0071] Figure 3D A schematic diagram of a top view structure of a common mode inductor provided by the utility model;

[0072] Figure 4 An electrical schematic diagram of a common mode inductor provided by the utility model;

[0073] Figure 5 The present invention provides a schematic structural diagram of an electric energy converter. DETAILED DESCRIPTION

[0074] The core of the utility model is to provide a harmonic suppression circuit and system. The three windings of the common mode inductor in the circuit are respectively connected to the differential mode filter modules and the common mode filter modules, and the lengths and impedances of the three windings are equal, so the three windings will not be overlapped, the winding is simple, and will not cause current imbalance. In addition, because the lengths of the three windings are equal, the lengths of the differential mode filter modules after being connected to the windings are equal, and the loop is shorter, which reduces the parasitic inductance and capacitance in the circuit and reduces the loss.

[0075] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0076] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a harmonic suppression circuit provided by the utility model, the harmonic suppression circuit comprises: a first differential mode filter module 1, a second differential mode filter module 2, a third differential mode filter module 3, a common mode inductor 4, a first common mode filter module 5, a second common mode filter module 6 and a third common mode filter module 7;

[0077] The first end of the first differential mode filter module 1 is respectively connected to the first phase power supply of the three-phase power supply, and the second end is connected to the second phase power supply of the three-phase power supply;

[0078] The first end of the second differential mode filter module 2 is respectively connected to the first phase power supply of the three-phase power supply, and the second end is connected to the third phase power supply of the three-phase power supply;

[0079] The first end of the third differential mode filter module 3 is respectively connected to the second phase power supply of the three-phase power supply, and the second end is connected to the third phase power supply of the three-phase power supply;

[0080] The first end of the first winding of the common-mode inductor 4 is connected to the first-phase power supply, the second end of the first winding is respectively connected to the first end of the first common-mode filter module 5 and the first end of the electric energy converter, the first end of the second winding is connected to the second-phase power supply, the second end of the second winding is respectively connected to the first end of the second common-mode filter module 6 and the first end of the electric energy converter, the first end of the third winding is connected to the third-phase power supply, the second end of the third winding is respectively connected to the first end of the third common-mode filter module 7 and the third end of the electric energy converter, and the lengths and impedances of the first winding, the second winding and the third winding are equal;

[0081] The second end of the first common mode filter module 5 is grounded;

[0082] A second end of the second common mode filtering module 6 is grounded;

[0083] A second terminal of the third common-mode filtering module 7 is grounded.

[0084] In the utility model, the harmonic suppression circuit is provided with a first differential mode filter module 1, a second differential mode filter module 2, a third differential mode filter module 3, a common mode inductor 4, a first common mode filter module 5, a second common mode filter module 6 and a third common mode filter module 7, wherein the first differential mode filter module 1, the second differential mode filter module 2, and the third differential mode filter module 3 can first perform differential mode filtering on the electric energy transmitted by the three-phase power supply, and the common mode inductor 4, the first common mode filter module 5, the second common mode filter module 6 and the third common mode filter module 7 can perform common mode filtering on the electric energy after differential mode filtering. Filtering, thereby suppressing the differential-mode and common-mode interference in the electric energy transmitted by the three-phase power supply, and transmitting cleaner electric energy to the electric energy converter, and the three windings of the common-mode inductor 4 are respectively connected to each differential-mode filter module and the common-mode filter module, and the lengths and impedances of the three windings are equal, so the three windings will not overlap, the winding is simple, and will not cause current imbalance. In addition, because the lengths of the three windings are equal, the lengths of each differential-mode filter module after being connected to the windings are equal, and the loop is shorter, which reduces the parasitic inductance and capacitance in the circuit and reduces the loss.

[0085] It should be noted that in practical applications, the structure of the harmonic suppression circuit is as follows: Figure 2 As shown, the top view of the common mode inductor 4 is as follows Figure 3A As shown, the top view of the common mode inductor 4 is as shown Figure 3B As shown, the side view structure diagram of the common mode inductor 4 is as follows Figure 3C As shown, the top view structure diagram of the common mode inductor 4 is as follows Figure 3D As shown, the electrical schematic diagram of the common mode inductor 4 is as follows Figure 4 As shown, Figure 4In the figure, N1 is the first winding of the common-mode inductor 4, N2 is the second winding of the common-mode inductor 4, and N3 is the third winding of the common-mode inductor 4. As shown in Figure 3, the common-mode inductor 4 is composed of three coil windings, a magnetic core, and an insulating plate, and three coil windings are evenly arranged around the magnetic core, and each coil winding is 120° apart. The coil of the common-mode inductor 4 is wound with flat copper; all electrical connections are integrated into the printed circuit board, without external wiring; the functional components are installed and positioned on the printed circuit board, which is convenient for integrated design and expansion. In addition, the coil of the common-mode inductor 4 is simple to wind and will not overlap. The coil lengths are equal and the impedances are the same, which is conducive to current sharing; the finished coil fits the magnetic core and has the same tightness, and the inductance consistency is good; there is no friction stress between the coil turns, which is conducive to insulation; the joints can be physically polished and painted, and there is no chemical pollution; the component joints are fixed to the printed circuit board by soldering, and the circuit component installation and packaging in the subsequent process are simple. The resistors and capacitors in the circuit are fixed to the printed circuit board by soldering, which is conducive to integration and expansion, equal line length, short loop, reduced parasitic inductance and capacitance, and no additional loss. If you want to expand the number of levels of harmonic suppression circuits, you can choose a multi-layered printed circuit board to accommodate more levels of capacitors and inductors, which can effectively limit the substantial increase in circuit volume.

[0086] The present embodiment provides a harmonic suppression circuit, in which a first differential mode filter module 1, a second differential mode filter module 2, a third differential mode filter module 3, a common mode inductor 4, a first common mode filter module 5, a second common mode filter module 6 and a third common mode filter module 7 are provided, wherein each differential mode filter module, common mode filter module and inductor are used for filtering to filter out high-order harmonics and electromagnetic interference in electric energy. In the present scheme, the three windings of the common mode inductor 4 are respectively connected to each differential mode filter module and the common mode filter module, and the lengths and impedances of the three windings are equal, so the three windings will not overlap, the winding is simple, and will not cause current imbalance. In addition, because the lengths of the three windings are equal, the lengths of each differential mode filter module after being connected to the windings are equal, and the loop is short, thereby reducing parasitic inductance and capacitance in the circuit and reducing losses.

[0087] Based on the above embodiments:

[0088] As an optional embodiment, the first differential mode filter module 1 includes: a first capacitor C1, a first resistor R1, a second capacitor C2 and a second resistor R2;

[0089] The first end of the first capacitor C1 is respectively connected to the first phase power supply, and the second end is respectively connected to the first end of the second capacitor C2 and the first end of the second resistor R2;

[0090] The second end of the second capacitor C2 is connected to the second phase power supply;

[0091] The first ends of the first resistors R1 are respectively connected to the first phase power supply, and the second ends are respectively connected to the first end of the second capacitor C2 and the first end of the second resistor R2;

[0092] The second end of the second resistor R2 is connected to the second phase power supply;

[0093] Correspondingly, the second differential mode filter module 2 includes: a first capacitor C1, a first resistor R1, a third capacitor C3 and a third resistor R3;

[0094] The first end of the first capacitor C1 is respectively connected to the first phase power supply, and the second end is respectively connected to the first end of the third capacitor C3 and the first end of the third resistor R3;

[0095] A second end of the third capacitor C3 is connected to a third phase power supply;

[0096] The first ends of the first resistors R1 are respectively connected to the first phase power supply, and the second ends are respectively connected to the first ends of the third capacitors C3 and the first ends of the third resistors R3;

[0097] A second end of the third resistor R3 is connected to a third phase power supply;

[0098] Correspondingly, the third differential mode filter module 3 includes: a second capacitor C2, a second resistor R2, a third capacitor C3 and a third resistor R3;

[0099] The first ends of the second capacitors C2 are respectively connected to the second phase power supply, and the second ends are respectively connected to the first ends of the third capacitors C3 and the first ends of the third resistors R3;

[0100] A second end of the third capacitor C3 is connected to a third phase power supply;

[0101] The first ends of the second resistors R2 are respectively connected to the second phase power supply, and the second ends are respectively connected to the first ends of the third capacitors C3 and the first ends of the third resistors R3;

[0102] A second end of the third resistor R3 is connected to the third phase power supply.

[0103] In the utility model, the first differential mode filter module 1 is composed of a first capacitor C1, a first resistor R1, a second capacitor C2 and a second resistor R2, wherein the first capacitor C1 and the first resistor R1 constitute a first RC filter circuit, the second capacitor C2 and the second resistor R2 constitute a second RC filter circuit, the above two RC filter circuits are arranged between the first phase power supply and the second phase power supply, and the differential mode interference between the first phase power supply and the second phase power supply is filtered out. Similarly, the second differential mode filter module 2 is composed of a first capacitor C1, a first resistor R1, a third capacitor C3 and a third resistor R3, wherein the third capacitor C3 and the third resistor R3 constitute a third RC filter circuit, the first PC filter circuit and the third RC filter circuit are arranged between the first phase power supply and the third phase power supply, filtering out the differential mode interference between the first phase power supply and the third phase power supply; similarly, the third differential mode filter module 3 is composed of a second capacitor C2, a second resistor R2, a third capacitor C3 and a third resistor R3, wherein the second PC filter circuit and the third RC filter circuit are arranged between the second phase power supply and the third phase power supply, filtering out the differential mode interference between the second phase power supply and the third phase power supply, the first differential mode filter module 1, the second differential mode filter module 2, and the third differential mode filter module 3 have simple structures, small volumes, and are easy to integrate.

[0104] As an optional embodiment, it further includes: a fourth differential mode filtering module, a fifth differential mode filtering module and a sixth differential mode filtering module;

[0105] A first end of the fourth differential mode filter module is connected to the first winding, and a second end is connected to the second winding;

[0106] A first end of the fifth differential mode filter module is connected to the first winding, and a second end is connected to the third winding;

[0107] The first end of the sixth differential mode filter module is connected to the second winding, and the second end is connected to the third winding. The first winding, the second winding and the third winding are evenly arranged around the magnetic core of the common mode inductor 4.

[0108] In the utility model, a fourth differential mode filter module, a fifth differential mode filter module and a sixth differential mode filter module are further provided in the harmonic suppression circuit. The fourth differential mode filter module is provided between the first winding and the second winding of the common mode inductor 4, and further filters out the differential mode interference between the first winding and the second winding; similarly, the fifth differential mode filter module is provided between the first winding and the third winding of the common mode inductor 4, and further filters out the differential mode interference between the first winding and the third winding; similarly, the sixth differential mode filter module is provided between the second winding and the third winding of the common mode inductor 4, and further filters out the differential mode interference between the second winding and the third winding; the differential mode interference in the electric energy is further filtered out, and the reliability of the scheme is improved.

[0109] As an optional embodiment, the fourth differential mode filtering module includes: a fourth capacitor C4 and a fifth capacitor C5;

[0110] A first end of the fourth capacitor C4 is connected to the first winding, and a second end is connected to a first end of the fifth capacitor C5;

[0111] A second end of the fifth capacitor C5 is connected to the second winding;

[0112] Correspondingly, the fifth differential mode filter module includes: a fourth capacitor C4 and a sixth capacitor C6;

[0113] A first end of the fourth capacitor C4 is connected to the first winding, and a second end is connected to a first end of the sixth capacitor C6;

[0114] A second end of the sixth capacitor C6 is connected to the third winding;

[0115] Correspondingly, the sixth differential mode filter module includes: a fifth capacitor C5 and a sixth capacitor C6;

[0116] A first end of the fifth capacitor C5 is connected to the second winding, and a second end is connected to a first end of the sixth capacitor C6;

[0117] A second end of the sixth capacitor C6 is connected to the third winding.

[0118] In the utility model, the fourth differential mode filter module is composed of the fourth capacitor C4 and the fifth capacitor C5, the fifth differential mode filter module is composed of the fourth capacitor C4 and the sixth capacitor C6, and the sixth differential mode filter module is composed of the fifth capacitor C5 and the sixth capacitor C6. Only two capacitors are set between the two windings to accurately perform differential mode filtering. The circuit elements are relatively few, the cost is low, and the installation and packaging of subsequent processes are convenient.

[0119] As an optional embodiment, the first common-mode filtering module 5 is a seventh capacitor C7, a first end of the seventh capacitor C7 is connected to the first winding and the first end of the electric energy converter, and a second end is grounded;

[0120] Correspondingly, the second common-mode filtering module 6 is an eighth capacitor C8, a first end of the eighth capacitor C8 is connected to the second winding and the second end of the electric energy converter, and a second end is grounded;

[0121] Correspondingly, the third common-mode filtering module 7 is a ninth capacitor C9, a first end of the ninth capacitor C9 is connected to the third winding and the third end of the electric energy converter, and a second end is grounded.

[0122] In the utility model, the first common-mode filter module 5 is the seventh capacitor C7, the second common-mode filter module 6 is the eighth capacitor C8, and the third common-mode filter module 7 is the ninth capacitor C9. Only one capacitor is used to perform common-mode filtering between any winding and the ground wire. The circuit elements are relatively few, the cost is low, and the installation and packaging of subsequent processes are convenient.

[0123] The utility model provides an embodiment corresponding to a harmonic suppression system, comprising: an electric energy converter and the above-mentioned harmonic suppression circuit, wherein the harmonic suppression circuit is connected to the electric energy converter.

[0124] The harmonic suppression system provided in this embodiment corresponds to the above-mentioned harmonic suppression circuit, and therefore has the same beneficial effects as the above-mentioned harmonic suppression circuit. Therefore, for the embodiments of the harmonic suppression system part, please refer to the description of the embodiments of the harmonic suppression circuit part, which will not be repeated here.

[0125] As an optional embodiment, the electric energy converter includes: a rectifier module, a seventh differential mode filter module, an inverter module, and a transformer module;

[0126] The rectifier module is connected to the first winding, the second winding and the third winding respectively, and is used to convert the first AC power transmitted by the common mode inductor 4 into corresponding DC power;

[0127] The seventh differential mode filter module is connected to the rectifier module and is used to filter the DC power accordingly;

[0128] The inverter module is connected to the rectifier module and is used to convert the filtered DC power into corresponding second AC power;

[0129] The transformer module is connected to the inverter module and the power grid respectively, and is used for converting the first voltage of the second AC power transmitted by the inverter module into the second voltage required by the power grid, and transmitting the converted second AC power to the power grid.

[0130] In the utility model, a rectifier module, a seventh differential mode filter module, an inverter module, and a transformer module are provided in the power converter, wherein the rectifier module can convert the first AC power transmitted by the common mode inductor 4 into the corresponding DC power, the seventh differential mode filter module will filter the DC power accordingly, the inverter module will convert the filtered DC power into the corresponding second AC power, and the transformer module will convert the first voltage of the second AC power transmitted by the inverter module into the second voltage required by the power grid, and transmit it to the power grid. The function of the entire power converter is to convert the first AC power of the first voltage transmitted by the common mode inductor 4 into the second AC power of the second voltage required by the power grid, and accurately complete the power transmission work from the three-phase power supply to the power grid.

[0131] It should be noted that the rectifier module can be a half-wave rectifier module or a full-wave rectifier module. If a full-wave rectifier module is selected, six rectifier diodes need to be set. In addition, the inverter module can be composed of four triodes and their corresponding diodes. The diode has a unidirectional conduction function to prevent the current from flowing back to the rectifier module. The specific structure is as follows Figure 4 shown.

[0132] As an optional embodiment, the seventh differential mode filter module includes: a first magnetic core inductor L1 and a tenth capacitor C10;

[0133] The first end of the first magnetic core inductor L1 is connected to the rectifier module and the inverter module respectively;

[0134] The first end of the tenth capacitor C10 is connected to the second end of the first magnetic core inductor L1 , and the second end is connected to the rectifier module and the inverter module respectively.

[0135] In the utility model, the seventh differential mode filter module is provided with a first magnetic core inductor L1 and a tenth capacitor C10, which constitute an LC filter module, wherein the magnetic core inductor has low loss, generates no noise during operation, and has a high performance-price ratio.

[0136] As an optional embodiment, the voltage transformation module includes: an eleventh capacitor C11, a transformer, a unidirectional conduction module and an eighth differential mode filtering module;

[0137] The first end of the eleventh capacitor C11 is connected to the inverter module, and the second end is connected to the first end of the primary winding of the transformer, and is used for filtering the second AC power output by the inverter module;

[0138] The second end of the primary winding of the transformer is connected to the inverter module, and the secondary winding is connected to the eighth differential mode filter module, for converting the first voltage of the filtered second AC electric energy into a second voltage;

[0139] An eighth differential mode filtering module is connected to the unidirectional conducting module, and is used for filtering the second alternating current power of the second voltage;

[0140] The unidirectional conduction module is connected to the power grid and is used for transmitting the filtered second alternating current power of the second voltage to the power grid.

[0141] In the utility model, the transformer module is provided with an eleventh capacitor C11, a transformer, a unidirectional conduction module and an eighth differential mode filter module, wherein the eleventh capacitor C11 and the eighth differential mode filter module both play a filtering role, and the transformer plays a role in voltage conversion, and the unidirectional conduction module ensures that the electric energy in the power grid will not be transmitted back to the harmonic suppression system, thereby improving the safety of the solution.

[0142] As an optional embodiment, the unidirectional conduction module includes: a first diode D1 and a second diode D2;

[0143] The anode of the first diode D1 is connected to the first end of the secondary winding of the transformer, and the cathode is connected to the eighth differential mode filter module;

[0144] The anode of the second diode D2 is connected to the second end of the secondary winding of the transformer, and the cathode is connected to the cathode of the first diode D1 and the eighth differential mode filter module respectively.

[0145] In the utility model, the unidirectional conduction module is composed of a first diode D1 and a second diode D2. The anodes of the two diodes are connected to the secondary winding of the transformer, and the cathodes are connected to the eighth differential mode filter module. Because the diodes have a unidirectional conduction effect, the electric energy is only transmitted from the anode to the cathode, so it can be ensured that the electric energy in the power grid will not be transmitted back to the harmonic suppression system, thereby improving the safety of the solution.

[0146] As an optional embodiment, the eighth differential mode filter module includes: a second magnetic core inductor L2 and a twelfth capacitor C12;

[0147] A first end of the second magnetic core inductor L2 is connected to the unidirectional conduction module, and a second end thereof is respectively connected to a first end of the twelfth capacitor C12 and a power grid;

[0148] The second end of the twelfth capacitor C12 is connected to the unidirectional conduction module and the power grid respectively.

[0149] In the utility model, the eighth differential mode filter module is provided with a second magnetic core inductor L2 and a twelfth capacitor C12, and the second magnetic core inductor L2 and the twelfth capacitor C12 constitute an LC filter module, wherein the magnetic core inductor has low loss, generates no noise during operation, and has a high performance-price ratio.

[0150] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0151] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A harmonic suppression circuit, characterized in that: include: A first differential mode filter module, a second differential mode filter module, a third differential mode filter module, a common mode inductor, a first common mode filter module, a second common mode filter module and a third common mode filter module; The first end of the first differential mode filter module is respectively connected to the first phase power supply of the three-phase power supply, and the second end is connected to the second phase power supply of the three-phase power supply; The first end of the second differential mode filter module is respectively connected to the first phase power supply of the three-phase power supply, and the second end is connected to the third phase power supply of the three-phase power supply; The first end of the third differential mode filter module is respectively connected to the second phase power supply of the three-phase power supply, and the second end is connected to the third phase power supply of the three-phase power supply; The first end of the first winding of the common-mode inductor is connected to the first-phase power supply, the second end of the first winding is respectively connected to the first end of the first common-mode filter module and the first end of the power converter, the first end of the second winding is connected to the second-phase power supply, the second end of the second winding is respectively connected to the first end of the second common-mode filter module and the first end of the power converter, the first end of the third winding is connected to the third-phase power supply, the second end of the third winding is respectively connected to the first end of the third common-mode filter module and the third end of the power converter, and the lengths and impedances of the first winding, the second winding and the third winding are equal; The second end of the first common mode filtering module is grounded; The second end of the second common mode filtering module is grounded; The second end of the third common-mode filtering module is grounded.

2. The harmonic suppression circuit according to claim 1, characterized in that: The first differential mode filter module includes: a first capacitor, a first resistor, a second capacitor and a second resistor; The first ends of the first capacitors are respectively connected to the first phase power supplies, and the second ends are respectively connected to the first ends of the second capacitors and the first ends of the second resistors; The second end of the second capacitor is connected to the second phase power supply; The first ends of the first resistors are respectively connected to the first phase power supplies, and the second ends are respectively connected to the first ends of the second capacitors and the first ends of the second resistors; The second end of the second resistor is connected to the second phase power supply; Correspondingly, the second differential mode filtering module includes: the first capacitor, the first resistor, a third capacitor and a third resistor; The first ends of the first capacitors are respectively connected to the first phase power supply, and the second ends are respectively connected to the first ends of the third capacitors and the first ends of the third resistors; The second end of the third capacitor is connected to the third phase power supply; The first ends of the first resistors are respectively connected to the first phase power supply, and the second ends are respectively connected to the first end of the third capacitor and the first end of the third resistor; The second end of the third resistor is connected to the third phase power supply; Correspondingly, the third differential mode filtering module includes: the second capacitor, the second resistor, the third capacitor and the third resistor; The first ends of the second capacitors are respectively connected to the second phase power supply, and the second ends are respectively connected to the first ends of the third capacitors and the first ends of the third resistors; The second end of the third capacitor is connected to the third phase power supply; The first ends of the second resistors are respectively connected to the second phase power supply, and the second ends are respectively connected to the first ends of the third capacitors and the first ends of the third resistors; The second end of the third resistor is connected to the third phase power supply.

3. The harmonic suppression circuit according to claim 1, characterized in that: Also includes: a fourth differential mode filter module, a fifth differential mode filter module and a sixth differential mode filter module; The first end of the fourth differential mode filter module is connected to the first winding, and the second end is connected to the second winding; The first end of the fifth differential mode filter module is connected to the first winding, and the second end is connected to the third winding; The first end of the sixth differential mode filter module is connected to the second winding, and the second end is connected to the third winding. The first winding, the second winding and the third winding are evenly arranged around the magnetic core of the common mode inductor.

4. The harmonic suppression circuit according to claim 3, characterized in that: The fourth differential mode filtering module comprises: a fourth capacitor and a fifth capacitor; A first end of the fourth capacitor is connected to the first winding, and a second end of the fourth capacitor is connected to the first end of the fifth capacitor; The second end of the fifth capacitor is connected to the second winding; Correspondingly, the fifth differential mode filtering module includes: the fourth capacitor and the sixth capacitor; A first end of the fourth capacitor is connected to the first winding, and a second end of the fourth capacitor is connected to the first end of the sixth capacitor; The second end of the sixth capacitor is connected to the third winding; Correspondingly, the sixth differential mode filtering module includes: the fifth capacitor and the sixth capacitor; The first end of the fifth capacitor is connected to the second winding, and the second end is connected to the first end of the sixth capacitor; The second end of the sixth capacitor is connected to the third winding.

5. The harmonic suppression circuit according to any one of claims 1 to 4, characterized in that: The first common-mode filtering module is a seventh capacitor, a first end of the seventh capacitor is connected to the first winding and the first end of the electric energy converter, and a second end is grounded; Correspondingly, the second common-mode filtering module is an eighth capacitor, a first end of the eighth capacitor is connected to the second winding and the second end of the electric energy converter, and a second end is grounded; Correspondingly, the third common-mode filtering module is a ninth capacitor, a first end of the ninth capacitor is connected to the third winding and the third end of the electric energy converter, and a second end is grounded.

6. A harmonic suppression system, characterized in that: include: An electric energy converter and a harmonic suppression circuit as claimed in any one of claims 1 to 5, wherein the harmonic suppression circuit is connected to the electric energy converter.

7. The harmonic suppression system according to claim 6, characterized in that: The electric energy converter comprises: a rectifier module, a seventh differential mode filter module, an inverter module, and a transformer module; The rectifier module is connected to the first winding, the second winding and the third winding respectively, and is used to convert the first AC power transmitted by the common mode inductor into corresponding DC power; The seventh differential mode filter module is connected to the rectifier module and is used to perform corresponding filtering on the DC power; The inverter module is connected to the rectifier module and is used to convert the filtered DC power into corresponding second AC power; The transformer module is connected to the inverter module and the power grid respectively, and is used to convert the first voltage of the second AC power transmitted by the inverter module into a second voltage required by the power grid, and transmit the converted second AC power to the power grid.

8. The harmonic suppression system according to claim 7, characterized in that: The seventh differential mode filter module comprises: a first magnetic core inductor and a tenth capacitor; The first end of the first magnetic core inductor is respectively connected to the rectifier module and the inverter module; The first end of the tenth capacitor is connected to the second end of the first magnetic core inductor, and the second end is connected to the rectifier module and the inverter module respectively.

9. The harmonic suppression system according to claim 7, characterized in that: The voltage transformation module comprises: an eleventh capacitor, a transformer, a unidirectional conduction module and an eighth differential mode filtering module; The first end of the eleventh capacitor is connected to the inverter module, and the second end is connected to the first end of the primary winding of the transformer, and is used to filter the second AC power output by the inverter module; The second end of the primary winding of the transformer is connected to the inverter module, and the secondary winding is connected to the eighth differential mode filter module, for converting the first voltage of the second AC electric energy after filtering into the second voltage; The eighth differential mode filtering module is connected to the unidirectional conducting module, and is used for filtering the second alternating current power of the second voltage; The unidirectional conduction module is connected to the power grid, and is used to transmit the second AC power of the second voltage after filtering to the power grid.

10. The harmonic suppression system according to claim 9, characterized in that: The one-way conducting module comprises: a first diode and a second diode; The anode of the first diode is connected to the first end of the secondary winding of the transformer, and the cathode is connected to the eighth differential mode filter module; The anode of the second diode is connected to the second end of the secondary winding of the transformer, and the cathode is connected to the cathode of the first diode and the eighth differential mode filtering module respectively.

11. The harmonic suppression system according to claim 9, characterized in that: The eighth differential mode filter module comprises: a second magnetic core inductor and a twelfth capacitor; A first end of the second magnetic core inductor is connected to the unidirectional conduction module, and a second end thereof is respectively connected to a first end of the twelfth capacitor and the power grid; The second end of the twelfth capacitor is connected to the unidirectional conduction module and the power grid respectively.

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