Multi-pulse rectifier based on passive harmonic suppression method

Abstract

The invention discloses a multi-pulse rectifier based on a passive harmonic suppression method. The multi-pulse rectifier comprises a phase-shifting transformer, a passive compensation device, a first three-phase diode rectifier bridge and a second three-phase diode rectifier bridge, the output end of the phase-shifting transformer is connected with the input end of the passive compensation device, the output end of the passive compensation device is connected with the input end of the first three-phase diode rectifier bridge and the input end of the second three-phase diode rectifier bridge, and the proportion of three windings on a first core column, a second core column and a third core column of the passive compensation device is 1: 1: square root of 3. When a three-phase imbalance factor exists in the multi-pulse rectifier, (12k + 6) + / -1 harmonic pollution is generated at the input end, the impedance of the passive compensation device to fundamental waves is 0 at the moment, and the impedance of the passive compensation device to (12k + 6) + / -1 harmonic is not 0, that is, the rectifier disclosed by the invention can be used for reducing the noise of the rectifier under the condition that the efficiency of a rectification system is not influenced. The problem that an existing rectifier is difficult to restrain three-phase imbalance is solved.

Description

Technical Field

[0001] The present invention relates to the field of electrical power technology, and in particular to a multi-pulse rectifier based on a passive harmonic suppression method. Background Art

[0002] Affected by factors such as three-phase load imbalance and system impedance imbalance, the power system generates a large amount of zero-sequence harmonic pollution, causing local overheating of the power system, reducing the service life of power equipment, and even causing safety hazards. At present, the distribution network mainly uses phase switching and compensation devices to suppress three-phase imbalance. However, manual or intelligent phase switching methods require changing the load circuit, which is complicated to operate and difficult to ensure uninterrupted power supply; although active compensation devices have better effects, the use of a large number of power electronic devices reduces reliability and increases costs; most of the existing passive compensation devices are large in size. In addition, both over-compensation and under-compensation will introduce a large number of harmonics into the power grid. Most of the existing harmonic compensation / suppression devices of multi-pulse rectifiers focus on the inherent harmonics of the rectifier system, and are powerless against the 5th and 7th harmonics ((12k+6)±1st harmonics) generated by three-phase imbalance. Summary of the invention

[0003] The embodiment of the present invention provides a multi-pulse rectifier based on a passive harmonic suppression method, which can solve the problem that the existing multi-pulse rectifier is difficult to suppress three-phase imbalance without affecting the efficiency of the rectification system.

[0004] An embodiment of the present invention provides a multi-pulse rectifier based on a passive harmonic suppression method, comprising: a phase-shifting transformer, a passive compensation device, a first three-phase diode rectifier bridge, and a second three-phase diode rectifier bridge;

[0005] The input end of the phase-shifting transformer is connected to an external three-phase voltage source, the output end of the phase-shifting transformer is connected to the input end of the passive compensation device, the output end of the passive compensation device is respectively connected to the input end of the first three-phase diode rectifier bridge and the input end of the second three-phase diode rectifier bridge, the output end of the first three-phase diode rectifier bridge is connected to the positive electrode of the external load, and the output end of the second three-phase diode rectifier bridge is connected to the negative electrode of the external load;

[0006] The passive compensation device is composed of a first core column, a second core column, and a third core column, the first core column is surrounded by a first winding, a second winding, and a third winding from top to bottom, the second core column is surrounded by a fourth winding, a fifth winding, and a sixth winding from top to bottom, and the third core column is surrounded by a seventh winding, an eighth winding, and a ninth winding from top to bottom;

[0007] The ratio of the number of turns of the first winding, the second winding, and the third winding is

[0008] The ratio of the number of turns of the fourth winding, the fifth winding, and the sixth winding is

[0009] The ratio of the number of turns of the seventh winding, the eighth winding, and the ninth winding is

[0010] Further, the input end of the passive compensation device includes: a first end of the first winding, a first end of the third winding, a first end of the fourth winding, a first end of the sixth winding, a second end of the seventh winding, and a first end of the ninth winding;

[0011] The output end of the passive compensation device includes: the second end of the second winding, the second end of the third winding, the second end of the fifth winding, the second end of the sixth winding, the second end of the eighth winding, and the second end of the ninth winding.

[0012] Further, the first end of the first winding is connected to the phase-shifting transformer, and the second end of the first winding is connected to the first end of the fifth winding;

[0013] The first end of the second winding is connected to the first end of the seventh winding, and the second end of the second winding is connected to the first three-phase diode rectifier bridge;

[0014] The first end of the third winding is connected to the phase-shifting transformer, and the second end of the third winding is connected to the first three-phase diode rectifier bridge;

[0015] The first end of the fourth winding is connected to the phase-shifting transformer, and the second end of the fourth winding is connected to the first end of the eighth winding;

[0016] The second end of the fifth winding is connected to the first three-phase diode rectifier bridge;

[0017] The first end of the sixth winding is connected to the phase-shifting transformer, and the second end of the sixth winding is connected to the second three-phase diode rectifier bridge;

[0018] The second end of the seventh winding is connected to the phase-shifting transformer;

[0019] The second end of the eighth winding is connected to the first three-phase diode rectifier bridge;

[0020] The first end of the ninth winding is connected to the phase-shifting transformer, and the second end of the ninth winding is connected to the second three-phase diode rectifier bridge.

[0021] Further, the phase-shifting transformer is composed of a fourth core column, a fifth core column, and a sixth core column; the fourth core column is surrounded by a first primary winding, a first secondary winding, and a second secondary winding; the fifth core column is surrounded by a second primary winding, a third secondary winding, and a fourth secondary winding; the sixth core column is surrounded by a third primary winding, a fifth secondary winding, and a sixth secondary winding;

[0022] Furthermore, the ratio of the number of turns of the first primary winding, the first secondary winding, and the second secondary winding is

[0023] The ratio of the number of turns of the second primary winding, the third secondary winding, and the fourth secondary winding is

[0024] The ratio of the number of turns of the third primary winding, the fifth secondary winding, and the sixth secondary winding is

[0025] Furthermore, the first primary winding, the second primary winding, and the third primary winding are connected in a triangle as input windings of the phase-shifting transformer;

[0026] The first secondary winding, the third secondary winding, and the fifth secondary winding are connected in a triangle as the first output winding of the phase-shifting transformer;

[0027] The second secondary winding, the fourth secondary winding, and the sixth secondary winding are connected in a star shape to serve as the second output winding of the phase-shifting transformer.

[0028] Further, the first end of the first output winding is connected to the second end of the seventh winding, the second end of the first output winding is connected to the first end of the fourth winding, and the third end of the first output winding is connected to the first end of the first winding;

[0029] The first end of the second output winding is connected to the first end of the ninth winding, the second end of the second output winding is connected to the first end of the sixth winding, and the third end of the second output winding is connected to the first end of the third winding.

[0030] Further, the first three-phase diode rectifier bridge is composed of a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode respectively;

[0031] An input end of the first diode is connected to the second end of the second winding, and an output end of the first diode is connected to an output end of the third diode;

[0032] An input end of the second diode is connected to an input end of the sixth diode, and an output end of the second diode is connected to a second end of the fifth winding;

[0033] An input end of the third diode is connected to the second end of the eighth winding, and an output end of the third diode is connected to the output end of the fifth diode;

[0034] The input end of the fourth diode is connected to the input end of the sixth diode, and the output end of the fourth diode is connected to the input end of the first diode;

[0035] An input end of the fifth diode is connected to an output end of the second diode;

[0036] An input end of the sixth diode is connected to the second three-phase diode rectifier bridge, and an output end of the sixth diode is connected to an input end of the third diode.

[0037] Further, the second three-phase diode rectifier bridge is composed of a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode respectively;

[0038] The input end of the seventh diode is connected to the second end of the ninth winding, and the output end of the seventh diode is connected to the output end of the ninth diode;

[0039] The output end of the eighth diode is connected to the second end of the third winding;

[0040] The input end of the ninth diode is connected to the second end of the sixth winding, and the output end of the ninth diode is connected to the input end of the sixth diode;

[0041] An input end of the tenth diode is connected to an input end of the eighth diode, and an output end of the tenth diode is connected to an input end of the seventh diode;

[0042] The input end of the eleventh diode is connected to the output end of the eighth diode, and the output end of the eleventh diode is connected to the output end of the ninth diode;

[0043] The input end of the twelfth diode is connected to the output end of the eighth diode, and the output end of the twelfth diode is connected to the input end of the ninth diode.

[0044] Furthermore, the input winding is connected to an external three-phase voltage source N, the output of the fifth diode is connected to the positive electrode of the external load, and the input of the eighth diode is connected to the negative electrode of the external load.

[0045] The following beneficial effects are achieved by implementing the present invention:

[0046] The present invention discloses a multi-pulse rectifier based on a passive harmonic suppression method, comprising: a phase-shifting transformer, a passive compensation device, a first three-phase diode rectifier bridge, and a second three-phase diode rectifier bridge; the output end of the phase-shifting transformer is connected to the input end of the passive compensation device, and the output end of the passive compensation device is respectively connected to the input end of the first three-phase diode rectifier bridge and the input end of the second three-phase diode rectifier bridge, wherein the passive compensation device is composed of a first core column, a second core column, and a third core column, and the ratio of the number of turns of the first winding, the second winding, and the third winding of the first core column is The ratio of the number of turns of the fourth winding, the fifth winding, and the sixth winding of the second core column is The ratio of the number of turns of the seventh winding, the eighth winding, and the ninth winding of the third core column is Since the ratio of the three windings on the first core column, the second core column, and the third core column of the passive compensation device is When the input end (grid) of the multi-pulse rectifier generates harmonic pollution of (12k+6)±1, the impedance of the passive compensation device to the fundamental wave is 0, while the impedance to the harmonic of (12k+6)±1 is not 0, that is, the present invention solves the harmonic interference problem caused by unbalanced three-phase load and unbalanced system impedance without affecting the efficiency of the rectification system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The diagram is a structural diagram of a multi-pulse rectifier based on a passive harmonic suppression method provided by an embodiment of the present invention.

[0048] Figure 2 It is a schematic structural diagram of a passive compensation device provided in one embodiment of the present invention.

[0049] Figure 3 It is a vector diagram of the impedance of the passive compensation device to the fundamental wave provided by an embodiment of the present invention.

[0050] Figure 4 It is a vector diagram of the passive compensation device provided by an embodiment of the present invention for 12k+5th harmonic impedance.

[0051] Figure 5 It is a vector diagram of the passive compensation device provided by an embodiment of the present invention for 12k+7th harmonic impedance. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0054] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0055] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0056] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0057] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0058] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0059] See also Figure 1 , is a structural schematic diagram of a multi-pulse rectifier based on a passive harmonic suppression method provided by an embodiment of the present invention, comprising: a phase-shifting transformer 1, a passive compensation device 2, a first three-phase diode rectifier bridge 3, and a second three-phase diode rectifier bridge 4;

[0060] The input end of the phase-shifting transformer 1 is connected to an external three-phase voltage source N, the output end of the phase-shifting transformer 1 is connected to the input end of the passive compensation device 2, the output end of the passive compensation device 2 is respectively connected to the input end of the first three-phase diode rectifier bridge 3 and the input end of the second three-phase diode rectifier bridge 4, the output end of the first three-phase diode rectifier bridge 3 is connected to the positive electrode of the external load u0, and the output end of the second three-phase diode rectifier bridge 4 is connected to the negative electrode of the external load u0;

[0061] Preferably, the input winding is connected to an external three-phase voltage source N, the output of the fifth diode is connected to the positive electrode of the external load u0, and the input of the eighth diode is connected to the negative electrode of the external load u0.

[0062] The passive compensation device 2 is composed of a first core column, a second core column, and a third core column. The first core column is surrounded by a first winding 21, a second winding 22, and a third winding 23 from top to bottom. The second core column is surrounded by a fourth winding 24, a fifth winding 25, and a sixth winding 26 from top to bottom. The third core column is surrounded by a seventh winding 27, an eighth winding 28, and a ninth winding 29 from top to bottom.

[0063] The ratio of the number of turns of the first winding 21, the second winding 22, and the third winding 23 is

[0064] The ratio of the number of turns of the fourth winding 24, the fifth winding 25, and the sixth winding 26 is

[0065] The ratio of the number of turns of the seventh winding 27, the eighth winding 28, and the ninth winding 29 is

[0066] Preferably, the input end of the passive compensation device 2 includes: a first end of the first winding 21, a first end of the third winding 23, a first end of the fourth winding 24, a first end of the sixth winding 26, a second end of the seventh winding 27, and a first end of the ninth winding 29;

[0067] The output end of the passive compensation device 2 includes: a second end of the second winding 22 , a second end of the third winding 23 , a second end of the fifth winding 25 , a second end of the sixth winding 26 , a second end of the eighth winding 28 , and a second end of the ninth winding 29 .

[0068] Preferably, the first end of the first winding 21 is connected to the phase-shifting transformer 1, and the second end of the first winding 21 is connected to the first end of the fifth winding 25;

[0069] The first end of the second winding 22 is connected to the first end of the seventh winding 27, and the second end of the second winding 22 is connected to the first three-phase diode rectifier bridge 3;

[0070] The first end of the third winding 23 is connected to the phase-shifting transformer 1, and the second end of the third winding 23 is connected to the first three-phase diode rectifier bridge 3;

[0071] A first end of the fourth winding 24 is connected to the phase-shifting transformer 1, and a second end of the fourth winding 24 is connected to a first end of the eighth winding 28;

[0072] The second end of the fifth winding 25 is connected to the first three-phase diode rectifier bridge 3;

[0073] The first end of the sixth winding 26 is connected to the phase-shifting transformer 1, and the second end of the sixth winding 26 is connected to the second three-phase diode rectifier bridge 4;

[0074] The second end of the seventh winding 27 is connected to the phase-shifting transformer 1;

[0075] The second end of the eighth winding 28 is connected to the first three-phase diode rectifier bridge 3;

[0076] A first end of the ninth winding 29 is connected to the phase-shifting transformer 1 , and a second end of the ninth winding 29 is connected to the second three-phase diode rectifier bridge 4 .

[0077] Preferably, the phase-shifting transformer 1 is composed of a fourth core column, a fifth core column, and a sixth core column; the fourth core column is surrounded by a first primary winding 11, a first secondary winding 14, and a second secondary winding 17; the fifth core column is surrounded by a second primary winding 12, a third secondary winding 15, and a fourth secondary winding 18; the sixth core column is surrounded by a third primary winding 13, a fifth secondary winding 16, and a sixth secondary winding 19;

[0078] Preferably, the ratio of the number of turns of the first primary winding 11, the first secondary winding 14, and the second secondary winding 17 is:

[0079] The ratio of the number of turns of the second primary winding 12, the third secondary winding 15, and the fourth secondary winding 18 is:

[0080] The ratio of the number of turns of the third primary winding 13, the fifth secondary winding 16, and the sixth secondary winding 19 is:

[0081] Preferably, the first primary winding 11, the second primary winding 12, and the third primary winding 13 are connected in a triangle as the input winding of the phase-shifting transformer 1;

[0082] The first secondary winding 14, the third secondary winding 15, and the fifth secondary winding 16 are connected in a triangle and serve as the first output winding of the phase-shifting transformer 1;

[0083] The second secondary winding 17 , the fourth secondary winding 18 , and the sixth secondary winding 19 are connected in a star shape to serve as the second output winding of the phase-shifting transformer 1 .

[0084] Preferably, the first end of the first output winding is connected to the second end of the seventh winding 27, the second end of the first output winding is connected to the first end of the fourth winding 24, and the third end of the first output winding is connected to the first end of the first winding 21;

[0085] The first end of the second output winding is connected to the first end of the ninth winding 29 , the second end of the second output winding is connected to the first end of the sixth winding 26 , and the third end of the second output winding is connected to the first end of the third winding 23 .

[0086] Preferably, the first three-phase diode rectifier bridge 3 is respectively composed of a first diode 31, a second diode 32, a third diode 33, a fourth diode 34, a fifth diode 35, and a sixth diode 36;

[0087] An input end of the first diode 31 is connected to the second end of the second winding 22 , and an output end of the first diode 31 is connected to an output end of the third diode 33 ;

[0088] The input end of the second diode 32 is connected to the input end of the sixth diode 36, and the output end of the second diode 32 is connected to the second end of the fifth winding 25;

[0089] An input end of the third diode 33 is connected to the second end of the eighth winding 28 , and an output end of the third diode 33 is connected to an output end of the fifth diode 35 ;

[0090] The input end of the fourth diode 34 is connected to the input end of the sixth diode 36 , and the output end of the fourth diode 34 is connected to the input end of the first diode 31 ;

[0091] The input end of the fifth diode 35 is connected to the output end of the second diode 32;

[0092] An input end of the sixth diode 36 is connected to the second three-phase diode rectifier bridge 4 , and an output end of the sixth diode 36 is connected to an input end of the third diode 33 .

[0093] Preferably, the second three-phase diode rectifier bridge 4 is respectively composed of a seventh diode 41, an eighth diode 42, a ninth diode 43, a tenth diode 44, an eleventh diode 45, and a twelfth diode 46;

[0094] The input end of the seventh diode 41 is connected to the second end of the ninth winding 29 , and the output end of the seventh diode 41 is connected to the output end of the ninth diode 43 ;

[0095] The output end of the eighth diode 42 is connected to the second end of the third winding 23;

[0096] An input end of the ninth diode 43 is connected to the second end of the sixth winding 26 , and an output end of the ninth diode 43 is connected to an input end of the sixth diode 36 ;

[0097] An input end of the tenth diode 44 is connected to an input end of the eighth diode 42 , and an output end of the tenth diode 44 is connected to an input end of the seventh diode 41 ;

[0098] The input end of the eleventh diode 45 is connected to the output end of the eighth diode 42 , and the output end of the eleventh diode 45 is connected to the output end of the ninth diode 43 ;

[0099] An input end of the twelfth diode 46 is connected to the output end of the eighth diode 42 , and an output end of the twelfth diode 46 is connected to the input end of the ninth diode 43 .

[0100] In a preferred embodiment of the present invention, the primary side of the phase-shifting transformer 1 is connected in a triangle, and the two sets of secondary windings are connected in a triangle and a star, respectively, which helps to eliminate zero-sequence harmonic pollution. Assume that the number of turns of each winding of the phase-shifting transformer is N a 、N a1 and N b1 , its turns ratio is

[0101] Furthermore, it is assumed that the input current of the multi-pulse rectifier satisfies:

[0102]

[0103] Where I is the amplitude of the input current.

[0104] According to the above formula and the winding structure of the phase-shifting transformer 1, the output current of the phase-shifting transformer 1 can be expressed as:

[0105]

[0106] Then, when the equivalent impedance of the multi-pulse rectifier or the three-phase grid voltage is unbalanced, the input end (grid) of the multi-pulse rectifier will produce (12k+6)±1 harmonic pollution. Therefore, the passive compensation device 2 needs to have no impedance to the fundamental wave (not affecting the efficiency of the rectifier system), but has impedance to the (12k+6)±1 harmonic.

[0107] Furthermore, Figure 2 From left to right, there are the first core column, the second core column, and the third core column. Assuming that the number of turns of the first winding 21, the fourth winding 24, and the seventh winding 27 is N1, the number of turns of the second winding 22, the fifth winding 25, and the eighth winding 28 is N2, and the number of turns of the third winding 23, the sixth winding 26, and the ninth winding 29 is N3, then, according to Figure 2 According to the above formula, the impedance of each winding to the fundamental wave is as follows Figure 3 To ensure that the passive compensation device 2 has no impedance to the fundamental wave, Figure 3 The vector sum of the vectors in must be zero. In this case, Furthermore, the impedance of each winding of the passive compensation device 2 to the 12k+5th harmonic is as follows: Figure 4 As shown. Figure 4 It is known that when When , the impedance of each winding of the passive compensation device 2 to the 12k+5th harmonic is not zero. Further, the impedance of each winding of the passive compensation device 2 to the 12k+7th harmonic is as follows: Figure 5 As shown. Figure 5 It is known that when When , the impedance of 12k+7 harmonics of each winding of the passive compensation device is also not zero.

[0108] In summary, combined Figure 3 , Figure 4 ,as well as Figure 5 It can be seen that when the passive compensation device 2 adopts Figure 2 The structure shown in the figure, and the turns ratio of each winding is When , the passive compensation device 2 has no impedance to the fundamental wave, but has impedance to the 12k-5 and 12k-7 harmonics.

[0109] The present embodiment provides a multi-pulse rectifier based on a passive harmonic suppression method, comprising: a phase-shifting transformer 1, a passive compensation device 2, a first three-phase diode rectifier bridge 3, and a second three-phase diode rectifier bridge 4; the output end of the phase-shifting transformer 1 is connected to the input end of the passive compensation device 2, and the output end of the passive compensation device 2 is respectively connected to the input end of the first three-phase diode rectifier bridge 3 and the input end of the second three-phase diode rectifier bridge, wherein the passive compensation device 2 is composed of a first core column, a second core column, and a third core column, and the ratio of the number of turns of the first winding 21, the second winding 22, and the third winding 23 of the first core column is The ratio of the number of turns of the fourth winding 24, the fifth winding 25, and the sixth winding 26 of the second core leg is The ratio of the number of turns of the seventh winding 27, the eighth winding 28, and the ninth winding 29 of the third core column is Since the ratio of the three windings on the first core leg, the second core leg, and the third core leg of the passive compensation device 2 is When the input end (grid) of the multi-pulse rectifier generates harmonic pollution of (12k+6)±1 order, the impedance of the passive compensation device 2 to the fundamental wave is 0, while the impedance to the harmonic of (12k+6)±1 order is not 0, that is, this embodiment solves the harmonic interference problem caused by unbalanced three-phase load and unbalanced system impedance without affecting the efficiency of the rectification system.

[0110] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A multi-pulse rectifier based on a passive harmonic suppression method, characterized in that: include: A phase-shifting transformer, a passive compensation device, a first three-phase diode rectifier bridge, and a second three-phase diode rectifier bridge; The input end of the phase-shifting transformer is connected to an external three-phase voltage source, the output end of the phase-shifting transformer is connected to the input end of the passive compensation device, the output end of the passive compensation device is respectively connected to the input end of the first three-phase diode rectifier bridge and the input end of the second three-phase diode rectifier bridge, the output end of the first three-phase diode rectifier bridge is connected to the positive electrode of the external load, and the output end of the second three-phase diode rectifier bridge is connected to the negative electrode of the external load; The passive compensation device is composed of a first core column, a second core column, and a third core column, the first core column is surrounded by a first winding, a second winding, and a third winding from top to bottom, the second core column is surrounded by a fourth winding, a fifth winding, and a sixth winding from top to bottom, and the third core column is surrounded by a seventh winding, an eighth winding, and a ninth winding from top to bottom; The ratio of the number of turns of the first winding, the second winding, and the third winding is 1:1:√3; The ratio of the number of turns of the fourth winding, the fifth winding, and the sixth winding is 1:1:√3; The ratio of the number of turns of the seventh winding, the eighth winding, and the ninth winding is 1:1:√3.

2. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 1, characterized in that: The input end of the passive compensation device includes: a first end of the first winding, a first end of the third winding, a first end of the fourth winding, a first end of the sixth winding, a second end of the seventh winding, and a first end of the ninth winding; The output end of the passive compensation device includes: the second end of the second winding, the second end of the third winding, the second end of the fifth winding, the second end of the sixth winding, the second end of the eighth winding, and the second end of the ninth winding.

3. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 2, characterized in that: The first end of the first winding is connected to the phase-shifting transformer, and the second end of the first winding is connected to the first end of the fifth winding; The first end of the second winding is connected to the first end of the seventh winding, and the second end of the second winding is connected to the first three-phase diode rectifier bridge; The first end of the third winding is connected to the phase-shifting transformer, and the second end of the third winding is connected to the first three-phase diode rectifier bridge; The first end of the fourth winding is connected to the phase-shifting transformer, and the second end of the fourth winding is connected to the first end of the eighth winding; The second end of the fifth winding is connected to the first three-phase diode rectifier bridge; The first end of the sixth winding is connected to the phase-shifting transformer, and the second end of the sixth winding is connected to the second three-phase diode rectifier bridge; The second end of the seventh winding is connected to the phase-shifting transformer; The second end of the eighth winding is connected to the first three-phase diode rectifier bridge; The first end of the ninth winding is connected to the phase-shifting transformer, and the second end of the ninth winding is connected to the second three-phase diode rectifier bridge.

4. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 3, characterized in that: The phase-shifting transformer is composed of a fourth core column, a fifth core column, and a sixth core column; the fourth core column is surrounded by a first primary winding, a first secondary winding, and a second secondary winding; the fifth core column is surrounded by a second primary winding, a third secondary winding, and a fourth secondary winding; the sixth core column is surrounded by a third primary winding, a fifth secondary winding, and a sixth secondary winding.

5. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 4, characterized in that: The ratio of the number of turns of the first primary winding, the first secondary winding, and the second secondary winding is √3:√3:1; The ratio of the number of turns of the second primary winding, the third secondary winding, and the fourth secondary winding is √3:√3:1; The ratio of the number of turns of the third primary winding, the fifth secondary winding, and the sixth secondary winding is √3:√3:

1.

6. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 5, characterized in that: The first primary winding, the second primary winding, and the third primary winding are connected in a triangle as input windings of the phase-shifting transformer; The first secondary winding, the third secondary winding, and the fifth secondary winding are connected in a triangle as the first output winding of the phase-shifting transformer; The second secondary winding, the fourth secondary winding, and the sixth secondary winding are connected in a star shape to serve as the second output winding of the phase-shifting transformer.

7. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 6, characterized in that: The first end of the first output winding is connected to the second end of the seventh winding, the second end of the first output winding is connected to the first end of the fourth winding, and the third end of the first output winding is connected to the first end of the first winding; The first end of the second output winding is connected to the first end of the ninth winding, the second end of the second output winding is connected to the first end of the sixth winding, and the third end of the second output winding is connected to the first end of the third winding.

8. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 7, characterized in that: The first three-phase diode rectifier bridge is composed of a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode respectively; An input end of the first diode is connected to the second end of the second winding, and an output end of the first diode is connected to an output end of the third diode; An input end of the second diode is connected to an input end of the sixth diode, and an output end of the second diode is connected to a second end of the fifth winding; An input end of the third diode is connected to the second end of the eighth winding, and an output end of the third diode is connected to the output end of the fifth diode; The input end of the fourth diode is connected to the input end of the sixth diode, and the output end of the fourth diode is connected to the input end of the first diode; An input end of the fifth diode is connected to an output end of the second diode; An input end of the sixth diode is connected to the second three-phase diode rectifier bridge, and an output end of the sixth diode is connected to an input end of the third diode.

9. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 8, characterized in that: The second three-phase diode rectifier bridge is composed of a seventh diode, an eighth diode, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode respectively; The input end of the seventh diode is connected to the second end of the ninth winding, and the output end of the seventh diode is connected to the output end of the ninth diode; The output end of the eighth diode is connected to the second end of the third winding; The input end of the ninth diode is connected to the second end of the sixth winding, and the output end of the ninth diode is connected to the input end of the sixth diode; An input end of the tenth diode is connected to an input end of the eighth diode, and an output end of the tenth diode is connected to an input end of the seventh diode; The input end of the eleventh diode is connected to the output end of the eighth diode, and the output end of the eleventh diode is connected to the output end of the ninth diode; The input end of the twelfth diode is connected to the output end of the eighth diode, and the output end of the twelfth diode is connected to the input end of the ninth diode.

10. A multi-pulse rectifier based on a passive harmonic suppression method as claimed in claim 9, characterized in that: The input winding is connected to an external three-phase voltage source, the output of the fifth diode is connected to the positive electrode of the external load, and the input of the eighth diode is connected to the negative electrode of the external load.

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