Triple boost auxiliary circuit for series type 12-pulse rectifier

Abstract

This invention relates to a triple-multiplier auxiliary circuit for a series-type 12-pulse rectifier, belonging to the field of power electronics technology. It solves the problems of existing pulse multiplier circuits used in the DC side of series-type 12-pulse rectifiers, which suffer from large turns ratios in the primary and secondary windings of the auxiliary transformer, resulting in significant leakage inductance and poor harmonic suppression. Furthermore, the large turns ratio and the presence of numerous diodes in the multiplier circuit also contribute to its complex structure and increased manufacturing difficulty. This invention's triple-multiplier auxiliary circuit, by adjusting the turns ratio of the primary and secondary windings of each auxiliary transformer, allows the auxiliary diodes D... f1 and auxiliary diode D f2 The conduction times of the two diodes are 1 / 3 or 1 / 4 of their respective input voltage cycles, enabling the first diode rectifier bridge and / or the second diode rectifier bridge to operate simultaneously or alternately, thereby achieving a pulse multiplication of 3 times. This invention is mainly used to achieve pulse multiplication.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a tripler auxiliary circuit. Background Technology

[0002] Compared to conventional three-phase 6-pulse rectifiers, series-type 12-pulse rectifiers not only double the rectifier's voltage rating and output power but also cancel the 5th and 7th harmonics in the input current. Therefore, they are often used in high-power applications such as medium- and high-voltage variable frequency speed control, metal smelting, wind power generation, and high-voltage direct current transmission. However, conventional series-type 12-pulse rectifiers still contain a large number of low-order harmonics (e.g., 11th, 13th, 23rd, and 25th harmonics) on the input side. When used alone, they still cannot meet the requirements of harmonic standards such as IEEE-519, leading to harmonic pollution to the power grid. Furthermore, due to the structural limitations of the 12-pulse rectifier, the output voltage ripple is still relatively large, reducing the power supply quality of the rectifier.

[0003] To increase the pulse count of a series-type 12-pulse rectifier while suppressing input current harmonics and output voltage ripple, existing technologies use a pulse multiplier circuit on the DC side of the rectifier. However, this pulse multiplier circuit uses many parallel diodes, resulting in a complex structure and a large turns ratio in the primary and secondary windings of the auxiliary transformer. This leads to significant leakage inductance in the transformer, reducing harmonic suppression effectiveness and resulting in relatively high input current harmonics in the 12-pulse rectifier. Furthermore, the large turns ratio increases the manufacturing difficulty of the transformer. Therefore, these problems urgently need to be addressed. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing pulse multiplier circuits used in DC-side series 12-pulse rectifiers. These circuits have large turns ratios in the primary and secondary windings of the auxiliary transformer, resulting in significant leakage inductance and poor harmonic suppression. Furthermore, the large turns ratios and the presence of numerous diodes in the multiplier circuit contribute to its complex structure and increased manufacturing difficulty. Therefore, this invention provides three novel triple-multiplier auxiliary circuits with different structures for use in series 12-pulse rectifiers.

[0005] First structure:

[0006] A triple-multiplier auxiliary circuit is applied to a series-type 12-pulse rectifier. The triple-multiplier auxiliary circuit is set on the DC side of the series-type 12-pulse rectifier and is used to multiply the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses. The series-type 12-pulse rectifier includes a phase-shifting transformer, a first diode rectifier bridge and a second diode rectifier bridge.

[0007] A phase-shifting transformer is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by the phase-shifting transformer are then sent to the first diode rectifier bridge and the second diode rectifier bridge, respectively.

[0008] The triple-multiplier auxiliary circuit includes an auxiliary single-phase rectifier bridge, a four-winding auxiliary transformer, a balancing reactor, and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2;

[0009] The positive output terminal of the first diode rectifier bridge is connected to one end of capacitor C1 and the positive terminal of the load simultaneously.

[0010] The negative output terminal of the second diode rectifier bridge is connected to the auxiliary diode D. f1 anode, auxiliary diode D f2 The anode of capacitor C2, one end of capacitor C2, and the negative terminal of the load are connected simultaneously.

[0011] The positive output terminal of the auxiliary single-phase rectifier bridge is connected to the negative output terminal of the first diode rectifier bridge, and the negative output terminal of the auxiliary single-phase rectifier bridge is connected to the positive output terminal of the second diode rectifier bridge.

[0012] The primary winding AB of the four-winding auxiliary transformer is connected to the same-name terminal of its secondary winding CD, the opposite-name terminal of its secondary winding AE, and the first AC input terminal of the auxiliary single-phase rectifier bridge.

[0013] The secondary winding CD of the four-winding auxiliary transformer is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge.

[0014] The corresponding terminal of the secondary winding AE of the four-winding auxiliary transformer is connected to the auxiliary diode D. f1 Cathode connection;

[0015] The opposite terminal of the primary winding AB of the four-winding auxiliary transformer is connected to the same terminal of its secondary winding BF and the center tap of the balancing reactor.

[0016] The opposite terminal of the secondary winding BF of the four-winding auxiliary transformer is connected to the auxiliary diode D. f2 Cathode connection;

[0017] The same-name terminal of the balancing reactor is connected to the other end of capacitor C1, and the opposite-name terminal of the balancing reactor is connected to the other end of capacitor C2.

[0018] Set the turns ratio of the primary and secondary windings of the four-winding auxiliary transformer so that the auxiliary diode D f1 and auxiliary diode D f2The conduction time of each diode rectifier bridge is 1 / 4 of its respective input voltage cycle, thereby enabling the first diode rectifier bridge and the second diode rectifier bridge to work simultaneously or alternately. When the first diode rectifier bridge and / or the second diode rectifier bridge are working, the output current of their rectifier bridges is a 4-level stepped DC current of equal width, thus achieving a pulse multiplication of 3 times.

[0019] The second structure:

[0020] A triple-multiplier auxiliary circuit is applied to a series-type 12-pulse rectifier. The triple-multiplier auxiliary circuit is set on the DC side of the series-type 12-pulse rectifier and is used to multiply the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses. The series-type 12-pulse rectifier includes a phase-shifting transformer, a first diode rectifier bridge and a second diode rectifier bridge.

[0021] A phase-shifting transformer is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by the phase-shifting transformer are then sent to the first diode rectifier bridge and the second diode rectifier bridge, respectively.

[0022] The triple-enhancing auxiliary circuit includes an auxiliary single-phase rectifier bridge, a first double-winding auxiliary transformer, a second double-winding auxiliary transformer, a triple-winding auxiliary transformer, and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2;

[0023] The positive output terminal of the first diode rectifier bridge is connected to one end of capacitor C1 and the negative output terminal of the auxiliary single-phase rectifier bridge at the same time; the positive output terminal of the auxiliary single-phase rectifier bridge is connected to the positive terminal of the load (8).

[0024] The negative output terminal of the second diode rectifier bridge is connected to the auxiliary diode D. f1 anode, auxiliary diode D f2 The anode of the capacitor, one end of the capacitor C2, and the negative terminal of the load (8) are connected simultaneously.

[0025] The opposite-named terminal of the primary winding AB of the three-winding auxiliary transformer is connected to the same-named terminal of its secondary winding AE, the negative output terminal of the first diode rectifier bridge, and the positive output terminal of the second diode rectifier bridge.

[0026] The opposite terminal of the secondary winding AE of the three-winding auxiliary transformer and the auxiliary diode D f1 Cathode connection,

[0027] The corresponding terminal of the secondary winding BF of the three-winding auxiliary transformer is connected to the auxiliary diode D. f2 Cathode connection;

[0028] The same-name terminal of the primary winding AB of the three-winding auxiliary transformer and the opposite-name terminal of its secondary winding BF, the opposite-name terminal of the primary winding of the first double-winding auxiliary transformer and the same-name terminal of the primary winding of the second double-winding auxiliary transformer are connected at the same time.

[0029] The same-name terminal of the primary winding of the first double-winding auxiliary transformer is connected to the other end of capacitor C1. The same-name terminal of the secondary winding of the first double-winding auxiliary transformer is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge. The opposite-name terminal of the secondary winding of the first double-winding auxiliary transformer is connected to the opposite-name terminal of the secondary winding of the second double-winding auxiliary transformer.

[0030] The opposite end of the primary winding of the second double-winding auxiliary transformer is connected to the other end of capacitor C2, and the same end of the secondary winding of the second double-winding auxiliary transformer is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge.

[0031] Set the turns ratio of the primary and secondary windings of the first double-winding auxiliary transformer, the second double-winding auxiliary transformer, and the three-winding auxiliary transformer, so that the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle, thereby enabling the first diode rectifier bridge and the second diode rectifier bridge to work simultaneously, achieving a 3-fold increase in the pulse number by the tripler auxiliary circuit.

[0032] The third structure:

[0033] A triple-multiplier auxiliary circuit is applied to a series-type 12-pulse rectifier. The triple-multiplier auxiliary circuit is set on the DC side of the series-type 12-pulse rectifier and is used to multiply the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses. The series-type 12-pulse rectifier includes a phase-shifting transformer, a first diode rectifier bridge, and a second diode rectifier bridge.

[0034] A phase-shifting transformer is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by the phase-shifting transformer are then sent to the first diode rectifier bridge and the second diode rectifier bridge, respectively.

[0035] The triple-enhancing auxiliary circuit includes an auxiliary single-phase rectifier bridge, a first double-winding auxiliary transformer, a second double-winding auxiliary transformer, a third double-winding auxiliary transformer, and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2;

[0036] The positive output terminal of the first diode rectifier bridge is connected to one end of capacitor C1 and the negative output terminal of the auxiliary single-phase rectifier bridge. The positive output terminal of the auxiliary single-phase rectifier bridge is connected to the auxiliary diode D. f1The cathode and the positive terminal of the load (8) are connected simultaneously;

[0037] The negative output terminal of the second diode rectifier bridge is connected to one end of capacitor C2 and auxiliary diode D. f2 The anode and the negative terminal of the load (8) are connected simultaneously;

[0038] The opposite-named terminal of the primary winding AB of the first double-winding auxiliary transformer is simultaneously connected to the negative output terminal of the first diode rectifier bridge and the positive output terminal of the second diode rectifier bridge.

[0039] The same-name terminal of the primary winding AB of the first double-winding auxiliary transformer and the opposite-name terminal of its secondary winding CD, the opposite-name terminal of the primary winding of the second double-winding auxiliary transformer, and the same-name terminal of the primary winding of the third double-winding auxiliary transformer are connected simultaneously.

[0040] The same-name terminal of the primary winding of the second double-winding auxiliary transformer is connected to the other end of capacitor C1, the same-name terminal of the secondary winding of the second double-winding auxiliary transformer is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge, and the opposite-name terminal of the secondary winding of the second double-winding auxiliary transformer is connected to the opposite-name terminal of the secondary winding of the third double-winding auxiliary transformer.

[0041] The opposite end of the primary winding of the third double-winding auxiliary transformer is connected to the other end of capacitor C2, and the same end of the secondary winding of the third double-winding auxiliary transformer is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge.

[0042] The corresponding terminal of the secondary winding CD of the first double-winding auxiliary transformer is connected to the auxiliary diode D. f1 anode and auxiliary diode D f2 The cathodes are connected simultaneously;

[0043] By setting the turns ratio of the primary and secondary windings of the first, second, and third double-winding auxiliary transformers, the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle, thereby enabling the first diode rectifier bridge and the second diode rectifier bridge to work simultaneously, realizing the tripler auxiliary circuit to triple the pulse number.

[0044] The beneficial effects of this invention are:

[0045] This invention adjusts the turns ratio of the primary and secondary windings of each auxiliary transformer to enable the auxiliary diode D... f1 and auxiliary diode D f2The conduction time of each diode is 1 / 3 or 1 / 4 of its respective input voltage cycle, so that the first diode rectifier bridge and the second diode rectifier bridge work simultaneously or alternately, thereby achieving a pulse multiplication of 3 times, effectively suppressing input current harmonics and output voltage pulsation. Furthermore, the pulse multiplication achieved by this setting method greatly reduces the turns ratio of the primary and secondary windings of each auxiliary transformer.

[0046] High voltage stress diodes in structure (i.e., diodes D connected in parallel with the load) f1 and D f2 The number of turns in the auxiliary transformer is reduced to two, which further significantly reduces the turns ratio of the primary and secondary windings, improves the harmonic suppression effect, and simplifies the circuit structure, making it more conducive to manufacturing.

[0047] The triple-multiplier auxiliary circuit for a series-type 12-pulse rectifier described in this invention achieves a triple increase in the pulse number of the series-type 12-pulse rectifier without the need for active switching devices or increasing the complexity of the phase-shifting transformer 1. This simultaneously reduces the input current harmonics and output voltage ripple of the multi-pulse rectifier. This invention has advantages such as simple circuit structure, high reliability, and good output voltage stability. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the tripler auxiliary circuit of the first structure described in Specific Implementation 1, applied to a series-type 12-pulse rectifier;

[0049] Figure 2 This is a schematic diagram of the current loop of the tripler auxiliary circuit with the first structure, operating in Mode I.

[0050] Figure 3 This is a schematic diagram of the current loop of the tripler auxiliary circuit with the first structure, operating in Mode II.

[0051] Figure 4 This is a schematic diagram of the current loop of the tripler auxiliary circuit with the first structure, operating in Mode III.

[0052] Figure 5 This is a schematic diagram of the current loop of the tripler auxiliary circuit with the first structure, operating in mode IV.

[0053] Figure 6 This is a schematic diagram of the structure of the tripler auxiliary circuit applied to a series-type 12-pulse rectifier according to the second structure described in Specific Implementation Method 4;

[0054] Figure 7 This is a schematic diagram of the current loop for the tripler auxiliary circuit of the second structure, operating in Mode I.

[0055] Figure 8This is a schematic diagram of the current loop of the tripler auxiliary circuit with the second structure, operating in Mode II.

[0056] Figure 9 This is a schematic diagram of the current loop for the tripler auxiliary circuit of the second structure when operating in Mode III.

[0057] Figure 10 This is a schematic diagram of the third structure of the tripler auxiliary circuit applied to a series-type 12-pulse rectifier as described in Specific Implementation Method Seven;

[0058] Figure 11 This is a schematic diagram of the current loop for the tripler auxiliary circuit of the third structure, operating in Mode I.

[0059] Figure 12 This is a schematic diagram of the current loop for the tripler auxiliary circuit of the third structure, operating in Mode II.

[0060] Figure 13 This is a schematic diagram of the current loop for the tripler auxiliary circuit of the third structure, operating in Mode III.

[0061] Figures 1 to 13 middle,

[0062] i A i B i C These are the three-phase input currents a, b, and c of phase-shifting transformer 1, respectively.

[0063] u A u B u C The three-phase AC voltage sources a, b, and c, respectively, are input from the power grid to the phase-shifting transformer 1;

[0064] i a1 i b1 i c1 These are the three-phase currents a, b, and c input to the first diode rectifier bridge 2, respectively.

[0065] i a2 i b2 i c2 These are the three-phase currents a, b, and c input to the second diode rectifier bridge 3, respectively.

[0066] i d1 This is the current output from the positive terminal of the first diode rectifier bridge 2;

[0067] i d2 The current input to the negative terminal of the second diode rectifier bridge 3 is the output current.

[0068] i d The current input to the positive terminal of the load;

[0069] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0070] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0071] u d This is the voltage across the load.

[0072] i c1 This represents the current flowing through capacitor C1;

[0073] i c2 This represents the current flowing through capacitor C2;

[0074] i f1 For the flow through auxiliary diode D f1 The current;

[0075] i f2 For the flow through auxiliary diode D f2 The current;

[0076] Figures 1 to 5 middle,

[0077] u p This is the voltage across the primary winding AB of the four-winding auxiliary transformer 5;

[0078] u s This is the voltage across the secondary winding CD of the four-winding auxiliary transformer 5;

[0079] u f1 This refers to the voltage across the secondary winding AE of the four-winding auxiliary transformer 5.

[0080] u f2 This is the voltage across the secondary winding BF of the four-winding auxiliary transformer 5;

[0081] N p This refers to the number of turns AB in the primary winding of the four-winding auxiliary transformer 5.

[0082] N s This refers to the number of turns of the secondary winding CD of the four-winding auxiliary transformer 5.

[0083] N f1 The number of turns of the secondary winding AE of the four-winding auxiliary transformer 5;

[0084] N f2 The number of turns BF in the secondary winding of the four-winding auxiliary transformer 5;

[0085] i s This refers to the current flowing through the auxiliary single-phase rectifier bridge 4;

[0086] i p1 The current flowing between the opposite-named terminal of the secondary winding AE and the opposite-named terminal of the secondary winding CD of the four-winding auxiliary transformer 5.

[0087] i p2 This is the sum of the currents flowing through capacitors C1 and C2;

[0088] Figures 6 to 9 middle,

[0089] u o This is the voltage across the primary winding AB of the three-winding auxiliary transformer 7;

[0090] u f1 This refers to the voltage across the secondary winding AE of the three-winding auxiliary transformer 7.

[0091] u f2 This is the voltage across the secondary winding BF of the three-winding auxiliary transformer 7;

[0092] u p1 This is the voltage across the primary winding of the first double-winding auxiliary transformer 5;

[0093] u s1 This is the voltage across the secondary winding of the first double-winding auxiliary transformer 5;

[0094] u p2 This is the voltage across the primary winding of the second double-winding auxiliary transformer 6;

[0095] u s2 This is the voltage across the secondary winding of the second double-winding auxiliary transformer 6;

[0096] i o1 It is the sum of the currents flowing through the primary winding AB and the secondary winding AE of the three-winding auxiliary transformer 7;

[0097] i o2 This is the sum of the currents flowing through capacitors C1 and C2;

[0098] i s This refers to the current flowing through the secondary winding of the second double-winding auxiliary transformer 6;

[0099] Figures 10 to 13 middle,

[0100] u o This is the voltage across the primary winding AB of the first double-winding auxiliary transformer 5;

[0101] u f This is the voltage across the secondary winding CD of the first double-winding auxiliary transformer 5;

[0102] up1 This is the voltage across the primary winding of the second double-winding auxiliary transformer 6;

[0103] u s1 This is the voltage across the secondary winding of the second double-winding auxiliary transformer 6;

[0104] u p2 This is the voltage across the primary winding of the third double-winding auxiliary transformer 7;

[0105] u s2 This is the voltage across the secondary winding of the third double-winding auxiliary transformer 7;

[0106] i o The current flowing through the primary winding AB of the first double-winding auxiliary transformer 5;

[0107] i s This refers to the current flowing through the secondary winding of the second double-winding auxiliary transformer 6. Detailed Implementation

[0108] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0109] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0110] This invention provides three structures of tripler auxiliary circuits for series-type 12-pulse rectifiers. The first structure is a 36-pulse rectifier, as detailed in embodiments one through three; the second structure is a 36-pulse rectifier, as detailed in embodiments four through six; and the third structure is a 36-pulse rectifier, as detailed in embodiments seven through nine. The details are as follows:

[0111] Specific Implementation Method 1: The following is combined with... Figure 1 This embodiment describes a first-structured triple-multiplier auxiliary circuit applied to a series-type 12-pulse rectifier. The triple-multiplier auxiliary circuit is located on the DC side of the series-type 12-pulse rectifier and is used to triple the number of 12 pulses in the series-type 12-pulse rectifier to obtain 36 pulses. The series-type 12-pulse rectifier includes a phase-shifting transformer 1, a first diode rectifier bridge 2, and a second diode rectifier bridge 3.

[0112] Phase-shifting transformer 1 is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by phase-shifting transformer 1 are sent to the first diode rectifier bridge 2 and the second diode rectifier bridge 3, respectively.

[0113] The triple-multiplier auxiliary circuit includes an auxiliary single-phase rectifier bridge (4), a four-winding auxiliary transformer (5), a balancing reactor (6), and an auxiliary diode (D). f1 and auxiliary diode D f2 Capacitors C1 and C2;

[0114] The positive output terminal of the first diode rectifier bridge 2 is connected to one end of capacitor C1 and the positive terminal of load 7 simultaneously.

[0115] The negative output terminal of the second diode rectifier bridge 3 is connected to the auxiliary diode D. f1 anode, auxiliary diode D f2 The anode of capacitor C2, one end of capacitor C2, and the negative terminal of load 7 are connected simultaneously.

[0116] The positive output terminal of the auxiliary single-phase rectifier bridge 4 is connected to the negative output terminal of the first diode rectifier bridge 2, and the negative output terminal of the auxiliary single-phase rectifier bridge 4 is connected to the positive output terminal of the second diode rectifier bridge 3.

[0117] The primary winding AB of the four-winding auxiliary transformer 5 is connected to the opposite terminal of its secondary winding CD, the opposite terminal of its secondary winding AE, and the first AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0118] The secondary winding CD of the four-winding auxiliary transformer 5 is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0119] The corresponding terminal of the secondary winding AE of the four-winding auxiliary transformer 5 is connected to the auxiliary diode D. f1 Cathode connection;

[0120] The opposite-named terminal of the primary winding AB of the four-winding auxiliary transformer 5 is connected to the same-named terminal of its secondary winding BF and the center tap of the balancing reactor 6.

[0121] The opposite terminal of the secondary winding BF of the four-winding auxiliary transformer 5 is connected to the auxiliary diode D. f2 Cathode connection;

[0122] The same-name terminal of balancing reactor 6 is connected to the other end of capacitor C1, and the opposite-name terminal of balancing reactor 6 is connected to the other end of capacitor C2.

[0123] Set the turns ratio of the primary and secondary windings of the four-winding auxiliary transformer 5 so that the auxiliary diode D f1 and auxiliary diode D f2The conduction time of each diode rectifier bridge is 1 / 4 of its respective input voltage cycle, so that the first diode rectifier bridge 2 and the second diode rectifier bridge 3 can work simultaneously or alternately, and when the first diode rectifier bridge 2 and / or the second diode rectifier bridge 3 are working, the output current of their rectifier bridges is a 4-level stepped DC current of equal width, thus achieving a pulse 3-fold increase.

[0124] This invention adjusts the turns ratio of the primary and secondary windings of each auxiliary transformer to enable the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each is 1 / 4 of its respective input voltage cycle, and when the first diode rectifier bridge 2 and / or the second diode rectifier bridge 3 are working, the output current of its rectifier bridge is a 4-level stepped DC current of equal width, thereby realizing a pulse 3 times multiplication, effectively suppressing input current harmonics and output voltage pulsation. Furthermore, the pulse 3 times multiplication achieved by this setting method greatly reduces the turns ratio of the primary and secondary windings of each auxiliary transformer.

[0125] When the auxiliary diode D f1 and auxiliary diode D f2 When the conduction time is 1 / 4 of the input voltage cycle, the rectifier is upgraded to a 36-pulse rectifier, and the input current harmonics and output voltage ripple of the rectifier are suppressed to the greatest extent.

[0126] High voltage stress diodes in structure (i.e., diodes D connected in parallel with the load) f1 and D f2 The number of turns in the auxiliary transformer is reduced to two, which further significantly reduces the turns ratio of the primary and secondary windings, improves the harmonic suppression effect, and simplifies the circuit structure, making it more conducive to manufacturing.

[0127] In this embodiment, the phase-shifting transformer 1 can be an existing isolated phase-shifting transformer, or it can be a phase-shifting transformer with a phase-shifting angle difference of 30° on the output side formed by connecting multiple transformers together, or a power electronic phase-shifting transformer.

[0128] This invention only requires adding a tripler auxiliary circuit to the DC side of a series-type 12-pulse rectifier to multiply it into a 36-pulse rectifier, effectively suppressing input current harmonics and output voltage pulsation of the rectifier.

[0129] The triple-multiplier auxiliary circuit described in this embodiment, applied to a series-type 12-pulse rectifier, achieves a triple increase in the pulse number of the multi-pulse rectifier without the need for active switching devices or increasing the complexity of the phase-shifting transformer 1. This simultaneously reduces the input current harmonics and output voltage ripple of the multi-pulse rectifier. This invention offers advantages such as simple circuit structure, high reliability, and good output voltage stability.

[0130] Specific Implementation Method Two: The following is combined with... Figure 1 This embodiment further describes the tripler auxiliary circuit of the first structure described in Embodiment 1 applied to a series-type 12-pulse rectifier. The auxiliary single-phase rectifier bridge 4 includes diode D. m1 diode D m2 diode D m3 and diode D m4 ;

[0131] Diode D m1 Cathode and diode D m2 After the cathode is connected, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge 4;

[0132] Diode D m3 anode and diode D m4 After the anode is connected, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge 4;

[0133] Diode D m2 The anode of the diode D is simultaneously with m4 After the cathode is connected, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge 4;

[0134] Diode D m1 anode and diode D m3 After the cathode is connected, it serves as the second AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0135] Specific Implementation Method Three: The following is combined with... Figures 2 to 5 This embodiment further describes the triplet auxiliary circuit of the first structure described in Embodiment 1, applied to a series-type 12-pulse rectifier. The triplet auxiliary circuit includes four operating modes, specifically:

[0136] Working Mode I: See Figure 2 , when u d1 >u d2 -u f1 <(u d2 -u s ) and u f2 d When / 2, diode D in auxiliary single-phase rectifier bridge 4 m1 and diode D m4 Reverse bias cutoff, diode D m2 and diode D m3 ​Forward conduction; the secondary windings AE and BF of the four-winding auxiliary transformer 5 are both in a non-operating state, while the primary winding AB and secondary winding CD of the four-winding auxiliary transformer 5 are both in an operating state. The auxiliary diode D connected to the secondary winding AE of the four-winding auxiliary transformer 5 is in a forward conduction state. f1 And the auxiliary diode D connected to the secondary winding BF f2 Reverse bias cutoff; at this time, the first diode rectifier bridge 2 and the second diode rectifier bridge 3 together supply power to the two ends of the load 7; among which,

[0137] u d The voltage across load 7;

[0138] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0139] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0140] u s This is the voltage across the secondary winding CD of the four-winding auxiliary transformer 5;

[0141] u f1 This refers to the voltage across the secondary winding AE of the four-winding auxiliary transformer 5.

[0142] u f2 This is the voltage across the secondary winding BF of the four-winding auxiliary transformer 5;

[0143] Working Mode II: See Figure 3 , when u d1 >u d2 -u f1 >(u d2 -u s ) and u f2 d When / 2, diode D in auxiliary single-phase rectifier bridge 4 m1 diode D m3 and diode D m4 Reverse bias cutoff, diode D m2 Forward conduction; the secondary windings CD and BF of the four-winding auxiliary transformer 5 are both in a non-operating state, while the primary winding AB and secondary winding AE of the four-winding auxiliary transformer 5 are both in an operating state. Simultaneously, the auxiliary diode D connected to the secondary winding BF... f2 Reverse bias cutoff, current flows through auxiliary diode D f1 current i f1 >0, current i f1 The current is injected into the negative output terminal of the first diode rectifier bridge 2. At this time, the second diode rectifier bridge 3 is not working, and its output current is zero. The first diode rectifier bridge 2 supplies power to both ends of the load 7.​

[0144] u d The voltage across load 7;

[0145] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0146] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0147] u s This is the voltage across the secondary winding CD of the four-winding auxiliary transformer 5;

[0148] u f1 This refers to the voltage across the secondary winding AE of the four-winding auxiliary transformer 5.

[0149] u f2 This is the voltage across the secondary winding BF of the four-winding auxiliary transformer 5;

[0150] Working Mode III: See Figure 4 , when u d1 d2 -u f1 <(u d2 -u s ) and u f2 d When / 2, diode D in auxiliary single-phase rectifier bridge 4 m2 and diode D m3 Reverse bias cutoff, diode D m1 and diode D m4 Forward conduction; the secondary windings AE and BF of the four-winding auxiliary transformer 5 are both in a non-operating state, while the primary winding AB and secondary winding CD of the four-winding auxiliary transformer 5 are both in an operating state. Simultaneously, the auxiliary diode D connected to the secondary winding AE of the four-winding auxiliary transformer 5 is in a forward conduction state. f1 And the auxiliary diode D connected to the secondary winding BF f2 When reverse biased and cut off, the first diode rectifier bridge 2 and the second diode rectifier bridge 3 together supply power to the two ends of the load 7; among which,

[0151] u d The voltage across load 7;

[0152] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0153] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0154] u s This is the voltage across the secondary winding CD of the four-winding auxiliary transformer 5;​​

[0155] u f1 This refers to the voltage across the secondary winding AE of the four-winding auxiliary transformer 5.

[0156] u f2 This is the voltage across the secondary winding BF of the four-winding auxiliary transformer 5;

[0157] Working Mode IV: See Figure 5 , when u d1 d2 -u f1 <(u d2 -u s ) and u f2 >u d When / 2, diode D in auxiliary single-phase rectifier bridge 4 m1 diode D m2 and diode D m3 Reverse bias cutoff, diode D m4 Forward conduction; the secondary windings CD and AE of the four-winding auxiliary transformer 5 are both in a non-operating state, while the primary winding AB and secondary winding BF of the four-winding auxiliary transformer 5 are both in an operating state. Simultaneously, the auxiliary diode D connected to the secondary winding AE... f1 With reverse bias cutoff, the secondary winding BF of the four-winding auxiliary transformer 5 is in operation, and current flows through the auxiliary diode D. f2 current i f2 >0, current i f2 The current is injected into the center tap of the balancing reactor 6. At this time, the first diode rectifier bridge 2 is not working and its output current is zero. The second diode rectifier bridge 3 supplies power to both ends of the load 7.

[0158] u d The voltage across load 7;

[0159] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0160] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0161] u s This is the voltage across the secondary winding CD of the four-winding auxiliary transformer 5;

[0162] u f1 This refers to the voltage across the secondary winding AE of the four-winding auxiliary transformer 5.

[0163] u f2 This is the voltage across the secondary winding BF of the four-winding auxiliary transformer 5.

[0164] ​In this embodiment, during modes II and IV, only one of the diodes connected in series with the load path is conducting (D). m2 Or D m4 Therefore, the loss of the triple-amplifier auxiliary circuit is reduced by about a quarter.

[0165] Specific Implementation Method Four: The following is combined with... Figure 6 This embodiment describes a triple-multiplier auxiliary circuit with the second structure applied to a series-type 12-pulse rectifier. The triple-multiplier auxiliary circuit is located on the DC side of the series-type 12-pulse rectifier and is used to triple the number of 12 pulses of the series-type 12-pulse rectifier to obtain 36 pulses. The series-type 12-pulse rectifier includes a phase-shifting transformer 1, a first diode rectifier bridge 2, and a second diode rectifier bridge 3.

[0166] Phase-shifting transformer 1 is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by phase-shifting transformer 1 are sent to the first diode rectifier bridge 2 and the second diode rectifier bridge 3, respectively.

[0167] The triple-multiplier auxiliary circuit includes an auxiliary single-phase rectifier bridge 4, a first double-winding auxiliary transformer 5, a second double-winding auxiliary transformer 6, a triple-winding auxiliary transformer 7, and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2;

[0168] The positive output terminal of the first diode rectifier bridge 2 is connected to one end of capacitor C1 and the negative output terminal of the auxiliary single-phase rectifier bridge 4 at the same time; the positive output terminal of the auxiliary single-phase rectifier bridge 4 is connected to the positive terminal of the load 8.

[0169] The negative output terminal of the second diode rectifier bridge 3 is connected to the auxiliary diode D. f1 anode, auxiliary diode D f2 The anode of capacitor C2, one end of capacitor C2, and the negative terminal of load 8 are connected simultaneously.

[0170] The opposite-named terminal of the primary winding AB of the three-winding auxiliary transformer 7 is connected to the same-named terminal of its secondary winding AE, the negative output terminal of the first diode rectifier bridge 2, and the positive output terminal of the second diode rectifier bridge 3.

[0171] The opposite terminal of the secondary winding AE of the three-winding auxiliary transformer 7 is connected to the auxiliary diode D. f1 Cathode connection,

[0172] The corresponding terminal of the secondary winding BF of the three-winding auxiliary transformer 7 is connected to the auxiliary diode D. f2 Cathode connection;

[0173] The same-name terminal of the primary winding AB of the three-winding auxiliary transformer 7 and the opposite-name terminal of its secondary winding BF, the opposite-name terminal of the primary winding of the first double-winding auxiliary transformer 5 and the same-name terminal of the primary winding of the second double-winding auxiliary transformer 6 are connected at the same time.

[0174] The same-name terminal of the primary winding of the first double-winding auxiliary transformer 5 is connected to the other end of the capacitor C1. The same-name terminal of the secondary winding of the first double-winding auxiliary transformer 5 is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge 4. The opposite-name terminal of the secondary winding of the first double-winding auxiliary transformer 5 is simultaneously connected to the opposite-name terminal of the secondary winding of the second double-winding auxiliary transformer 6.

[0175] The opposite end of the primary winding of the second double-winding auxiliary transformer 6 is connected to the other end of the capacitor C2, and the same end of the secondary winding of the second double-winding auxiliary transformer 6 is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0176] Set the turns ratio of the primary and secondary windings of the first double-winding auxiliary transformer 5, the second double-winding auxiliary transformer 6, and the three-winding auxiliary transformer 7 so that the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle, so that the first diode rectifier bridge 2 and the second diode rectifier bridge 3 work simultaneously, realizing the tripler auxiliary circuit to triple the pulse number.

[0177] In this embodiment, the present invention adjusts the turns ratio of the primary and secondary windings of each auxiliary transformer to enable the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each is 1 / 3 of its respective input voltage cycle, and the first diode rectifier bridge 2 and the second diode rectifier bridge 3 work simultaneously to achieve a 3-fold increase in the pulse number, effectively suppressing input current harmonics and output voltage pulsation. Furthermore, the 3-fold increase in pulse achieved by this setting method greatly reduces the turns ratio of the primary and secondary windings of each auxiliary transformer.

[0178] When the auxiliary diode D f1 and auxiliary diode D f2 When the conduction time is 1 / 3 of the input voltage cycle, the rectifier is upgraded to a 36-pulse rectifier, and the input current harmonics and output voltage ripple of the rectifier are suppressed to the greatest extent.

[0179] High voltage stress diodes in structure (i.e., diodes D connected in parallel with the load) f1 and D f2 The number of turns in the auxiliary transformer is reduced to two, which further significantly reduces the turns ratio of the primary and secondary windings, improves the harmonic suppression effect, and simplifies the circuit structure, making it more conducive to manufacturing.

[0180] In this embodiment, the phase-shifting transformer 1 can be an existing isolated phase-shifting transformer, or it can be a phase-shifting transformer with a phase-shifting angle difference of 30° on the output side formed by connecting multiple transformers together, or a power electronic phase-shifting transformer.

[0181] This invention only requires adding a tripler auxiliary circuit to the DC side of a series-type 12-pulse rectifier to multiply it into a 36-pulse rectifier, effectively suppressing input current harmonics and output voltage pulsation of the rectifier.

[0182] The triple-multiplier auxiliary circuit described in this embodiment, applied to a series-type 12-pulse rectifier, achieves a triple increase in the pulse number of the multi-pulse rectifier without the need for active switching devices or increasing the complexity of the phase-shifting transformer 1. This simultaneously reduces the input current harmonics and output voltage ripple of the multi-pulse rectifier. This invention offers advantages such as simple circuit structure, high reliability, and good output voltage stability.

[0183] Specific Implementation Method Five: The following is combined with... Figure 6 This embodiment further explains the tripler auxiliary circuit of the second structure described in Embodiment 4 applied to a series-type 12-pulse rectifier. The auxiliary single-phase rectifier bridge 4 includes diodes D1, D2, D3, and D4.

[0184] After the cathode of diode D1 is connected to the anode of diode D3, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0185] After the cathode of diode D2 and the anode of diode D4 are connected, they serve as the second AC input terminal of the auxiliary single-phase rectifier bridge 4;

[0186] After the anode of diode D1 is connected to the anode of diode D2, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge 4.

[0187] After the cathode of diode D3 is connected to the cathode of diode D4, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge 4.

[0188] Specific Implementation Method Six: The following is combined with... Figures 7 to 9 This embodiment further describes the triplet auxiliary circuit with the second structure described in Embodiment 5, applied to a series-type 12-pulse rectifier. The triplet auxiliary circuit includes three operating modes, specifically:

[0189] Working Mode I: See Figure 7 , when u f1 d2 and-u f2 <(u d2 +u​o At that time, the first double-winding auxiliary transformer 5, the second double-winding auxiliary transformer 6, the three-winding auxiliary transformer 7, and the auxiliary diode D... f1 and auxiliary diode D f2 Capacitors C1 and C2 are both in a non-operating state. At this time, the output currents of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are equal, and the load 8 is powered through the auxiliary single-phase rectifier bridge 4; among which,

[0190] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0191] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0192] u f1 This refers to the voltage across the secondary winding AE of the three-winding auxiliary transformer 7.

[0193] u f2 This is the voltage across the secondary winding BF of the three-winding auxiliary transformer 7;

[0194] u o This is the voltage across the primary winding AB of the three-winding auxiliary transformer 7;

[0195] Working Mode II: See Figure 8 , when u f1 >u d2 At that time, the primary winding AB and secondary winding AE of the three-winding auxiliary transformer 7 are both in operation, and the auxiliary diode D connected to the secondary winding AE is also in operation. f1 Forward conduction, current flows through auxiliary diode D f1 current i f1 >0, current i f1 The current is injected into the negative output terminal of the first diode rectifier bridge 2; the secondary winding BF of the three-winding auxiliary transformer 7 is in a non-operating state, and the auxiliary diode D connected to the secondary winding BF of the three-winding auxiliary transformer 7 is in a non-operating state. f2 With reverse bias cutoff, diodes D1 and D4 in the auxiliary single-phase rectifier bridge 4 are reverse biased and cut off, while diodes D2 and D3 are forward biased and conduct. At this time, the output current of the first diode rectifier bridge 2 is greater than the output current of the second diode rectifier bridge 3, and diodes D2 and D3 in the auxiliary single-phase rectifier bridge 4 jointly supply power to the two ends of the load 8; where,

[0196] u f1 This refers to the voltage across the secondary winding AE of the three-winding auxiliary transformer 7.

[0197] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0198] Working Mode III: See Figure 9 , when -u f2 >(u d2 +u o At this time, both the primary winding AB and the secondary winding BF of the three-winding auxiliary transformer 7 are in operation, and the auxiliary diode D connected to the secondary winding BF is also in operation. f2 Forward conduction, current flows through auxiliary diode D f2 current i f2 >0; The secondary winding AE of the three-winding auxiliary transformer 7 is in a non-operating state, and the auxiliary diode D connected to the secondary winding AE of the three-winding auxiliary transformer 7 is also in a non-operating state. f1 With reverse bias cutoff, diodes D2 and D3 in the auxiliary single-phase rectifier bridge 4 are reverse biased and cut off, while diodes D1 and D4 are forward biased and conduct. At this time, the output current of the first diode rectifier bridge 2 is less than the output current of the second diode rectifier bridge 3, and diodes D1 and D4 in the auxiliary single-phase rectifier bridge 4 jointly supply power to the two ends of the load 8; where,

[0199] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0200] u f2 This is the voltage across the secondary winding BF of the three-winding auxiliary transformer 7;

[0201] u o This is the voltage across the primary winding AB of the three-winding auxiliary transformer 7.

[0202] In this embodiment, the current stress is 1.6i when the first diode rectifier bridge 2 and the second diode rectifier bridge 3, which are connected to the tripler auxiliary circuit, operate simultaneously. d In existing technology, the two rectifier bridges connected to the existing 36-pulse pulse multiplier circuit operate alternately, resulting in a current stress of 2i for the two rectifier bridges. d Therefore, the tripler auxiliary circuit of the present invention significantly reduces the current stress of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 in the series 12-pulse rectifier.

[0203] Specific Implementation Method Seven: The following is combined with... Figure 10 This embodiment describes a third structure of a triple-multiplier auxiliary circuit applied to a series-type 12-pulse rectifier. The triple-multiplier auxiliary circuit is located on the DC side of the series-type 12-pulse rectifier and is used to triple the number of pulses in the series-type 12-pulse rectifier to obtain 36 pulses. The series-type 12-pulse rectifier includes a phase-shifting transformer 1, a first diode rectifier bridge 2, and a second diode rectifier bridge 3.

[0204] Phase-shifting transformer 1 is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by phase-shifting transformer 1 are sent to the first diode rectifier bridge 2 and the second diode rectifier bridge 3, respectively.

[0205] The triple-multiplier auxiliary circuit includes an auxiliary single-phase rectifier bridge 4, a first double-winding auxiliary transformer 5, a second double-winding auxiliary transformer 6, a third double-winding auxiliary transformer 7, and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2;

[0206] The positive output terminal of the first diode rectifier bridge 2 is connected to one end of capacitor C1 and the negative output terminal of the auxiliary single-phase rectifier bridge 4. The positive output terminal of the auxiliary single-phase rectifier bridge 4 is connected to the auxiliary diode D. f1 The cathode and the positive terminal of load 8 are connected simultaneously;

[0207] The negative output terminal of the second diode rectifier bridge 3 is connected to one end of capacitor C2 and auxiliary diode D. f2 The anode and the negative terminal of load 8 are connected simultaneously;

[0208] The opposite-named terminal of the primary winding AB of the first double-winding auxiliary transformer 5 is simultaneously connected to the negative output terminal of the first diode rectifier bridge 2 and the positive output terminal of the second diode rectifier bridge 3.

[0209] The same-name terminal of the primary winding AB of the first double-winding auxiliary transformer 5 and the opposite-name terminal of its secondary winding CD, the opposite-name terminal of the primary winding of the second double-winding auxiliary transformer 6, and the same-name terminal of the primary winding of the third double-winding auxiliary transformer 7 are connected simultaneously.

[0210] The same-name terminal of the primary winding of the second double-winding auxiliary transformer 6 is connected to the other end of the capacitor C1. The same-name terminal of the secondary winding of the second double-winding auxiliary transformer 6 is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge 4. The opposite-name terminal of the secondary winding of the second double-winding auxiliary transformer 6 is connected to the opposite-name terminal of the secondary winding of the third double-winding auxiliary transformer 7.

[0211] The opposite end of the primary winding of the third double-winding auxiliary transformer 7 is connected to the other end of the capacitor C2, and the same end of the secondary winding of the third double-winding auxiliary transformer 7 is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0212] The corresponding terminal of the secondary winding CD of the first double-winding auxiliary transformer 5 is connected to the auxiliary diode D. f1 anode and auxiliary diode D f2 The cathodes are connected simultaneously;

[0213] By setting the turns ratio of the primary and secondary windings of the first double-winding auxiliary transformer 5, the second double-winding auxiliary transformer 6, and the third double-winding auxiliary transformer 7, the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle, so that the first diode rectifier bridge 2 and the second diode rectifier bridge 3 work simultaneously, realizing the tripler auxiliary circuit to triple the pulse number.

[0214] In this embodiment, the present invention adjusts the turns ratio of the primary and secondary windings of each auxiliary transformer to enable the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle. When the first diode rectifier bridge 2 and the second diode rectifier bridge 3 work at the same time, the pulse is multiplied by 3, which effectively suppresses the input current harmonics and the output voltage pulsation. Furthermore, the pulse multiplication achieved by this setting method greatly reduces the turns ratio of the primary and secondary windings of each auxiliary transformer.

[0215] When the auxiliary diode D f1 and auxiliary diode D f2 When the conduction time is 1 / 3 of the input voltage cycle, the rectifier is upgraded to a 36-pulse rectifier, and the input current harmonics and output voltage ripple of the rectifier are suppressed to the greatest extent.

[0216] High voltage stress diodes in structure (i.e., diodes D connected in parallel with the load) f1 and D f2 The number of turns in the auxiliary transformer is reduced to two, which further significantly reduces the turns ratio of the primary and secondary windings, improves the harmonic suppression effect, and simplifies the circuit structure, making it more conducive to manufacturing.

[0217] In this embodiment, the phase-shifting transformer 1 can be an existing isolated phase-shifting transformer, or it can be a phase-shifting transformer with a phase-shifting angle difference of 30° on the output side formed by connecting multiple transformers together, or a power electronic phase-shifting transformer.

[0218] This invention only requires adding a tripler auxiliary circuit to the DC side of a series-type 12-pulse rectifier to multiply it into a 36-pulse rectifier, effectively suppressing input current harmonics and output voltage pulsation of the rectifier.

[0219] The triple-multiplier auxiliary circuit described in this embodiment, applied to a series-type 12-pulse rectifier, achieves a triple increase in the pulse number of the multi-pulse rectifier without the need for active switching devices or increasing the complexity of the phase-shifting transformer 1. This simultaneously reduces the input current harmonics and output voltage ripple of the multi-pulse rectifier. This invention offers advantages such as simple circuit structure, high reliability, and good output voltage stability.

[0220] Detailed Implementation Method Eight: The following is combined with... Figure 10 This embodiment further explains the tripler auxiliary circuit of the third structure applied to a series 12-pulse rectifier described in Embodiment 7. The auxiliary single-phase rectifier bridge 4 includes diodes D1, D2, D3, and D4.

[0221] After the anode of diode D2 is connected to the cathode of diode D4, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0222] After the anode of diode D1 and the cathode of diode D3 are connected, they serve as the second AC input terminal of the auxiliary single-phase rectifier bridge 4;

[0223] After the anode of diode D3 is connected to the anode of diode D4, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge 4.

[0224] After the cathode of diode D1 is connected to the cathode of diode D2, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge 4.

[0225] Specific Implementation Method Nine: The following is combined with... Figures 11 to 13 This embodiment further describes the third structure of the triplet auxiliary circuit applied to a series-type 12-pulse rectifier described in Embodiment 8. The triplet auxiliary circuit includes three operating modes, specifically:

[0226] Working Mode I: See Figure 11 , when u f <(u d1 -u o ) and -u f <(u d2 +u o At that time, the first double-winding auxiliary transformer 5, the second double-winding auxiliary transformer 6, the third double-winding auxiliary transformer 7, and the auxiliary diode D... f1 and auxiliary diode D f22 All are in a non-operating state. At this time, the output currents of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are equal, and all diodes in the auxiliary single-phase rectifier bridge 4 supply power to the two ends of the load 8; among which,

[0227] u d1This is the output voltage of the first diode rectifier bridge 2;

[0228] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0229] u o This is the voltage across the primary winding AB of the first double-winding auxiliary transformer 5;

[0230] u f This is the voltage across the secondary winding CD of the first double-winding auxiliary transformer 5;

[0231] Working Mode II: See Figure 12 , when u f >(u d1 -u o At this time, the first double-winding auxiliary transformer 5, the second double-winding auxiliary transformer 6, and the third double-winding auxiliary transformer 7 are all in operation, and the auxiliary diode D connected to the secondary winding CD of the first double-winding auxiliary transformer 5 is in operation. f1 Forward conduction, current flows through auxiliary diode D f1 current i f1 >0, auxiliary diode D f2 Reverse bias cutoff; in the auxiliary single-phase rectifier bridge 4, diodes D1 and D4 are reverse biased and cut off, while diodes D2 and D3 are forward biased and conduct. At this time, the output current of the first diode rectifier bridge 2 is greater than the output current of the second diode rectifier bridge 3, and diodes D2 and D3 in the auxiliary single-phase rectifier bridge 4 jointly supply power to the two ends of the load 8; where u d1 This is the output voltage of the first diode rectifier bridge 2;

[0232] u o This is the voltage across the primary winding AB of the first double-winding auxiliary transformer 5;

[0233] u f This is the voltage across the secondary winding CD of the first double-winding auxiliary transformer 5;

[0234] Working Mode III: See Figure 13 , when -u f >(u d2 +u o At this time, the first double-winding auxiliary transformer 5, the second double-winding auxiliary transformer 6, and the third double-winding auxiliary transformer 7 are all in operation, and the auxiliary diode D connected to the secondary winding CD of the first double-winding auxiliary transformer 5 is in operation. f2 Forward conduction, current flows through auxiliary diode D f2 current i f2 >0, auxiliary diode D f1Reverse bias cutoff; in the auxiliary single-phase rectifier bridge 4, diodes D2 and D3 are reverse biased and cut off, while diodes D1 and D4 are forward biased and conduct. At this time, the output current of the first diode rectifier bridge 2 is less than the output current of the second diode rectifier bridge 3, and diodes D1 and D4 in the auxiliary single-phase rectifier bridge 4 jointly supply power to the two ends of the load 8. Where, u d2 This is the output voltage of the second diode rectifier bridge 3;

[0235] u o This is the voltage across the primary winding AB of the first double-winding auxiliary transformer 5;

[0236] u f This is the voltage across the secondary winding CD of the first double-winding auxiliary transformer 5.

[0237] In this embodiment, the current stress is 1.6i when the first diode rectifier bridge 2 and the second diode rectifier bridge 3, which are connected to the tripler auxiliary circuit, operate simultaneously. d In existing technology, the two rectifier bridges connected to the existing 36-pulse pulse multiplier circuit operate alternately, resulting in a current stress of 2i for the two rectifier bridges. d Therefore, the tripler auxiliary circuit of the present invention significantly reduces the current stress of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 in the series 12-pulse rectifier.

[0238] Principle Analysis:

[0239] The three structures of the present invention applied to the tripler auxiliary circuit of a series 12-pulse rectifier are all based on the idea of ​​extracting a square wave current from the DC side of the series 12-pulse rectifier to modulate and increase the output current level of the first diode rectifier bridge 2 and the second diode rectifier bridge 3. Then, by optimizing the turns ratio of the primary and secondary windings of the auxiliary transformer, the auxiliary diode D... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 or 1 / 4 of the input voltage cycle. The first diode rectifier bridge 2 and the second diode rectifier bridge 3 work simultaneously or alternately. Then, according to the AC / DC side current relationship and the DC side voltage relationship, the pulse number of the rectifier is increased from 12 times to 36, which effectively suppresses the input current harmonics and the output voltage pulsation.

[0240] Furthermore, compared to the existing triple-multiplier circuits, the triple-multiplier auxiliary circuit of this invention achieves a 3x pulse multiplication, significantly reducing the turns ratio of the primary and secondary windings of each auxiliary transformer; and structurally, it utilizes high-voltage-stress diodes (i.e., diodes D connected in parallel with the load). f1 and D f2The number of turns in the auxiliary transformer is reduced to two, which further reduces the turns ratio of the primary and secondary windings, improves the harmonic suppression effect, and simplifies the circuit structure, making it more conducive to manufacturing. At the same time, this invention solves the problems of high input current harmonic content and large output voltage ripple in existing series-type 12-pulse rectifiers without increasing the complexity of the rectifier or reducing the stability of the output voltage.

[0241] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A triple-multiplier auxiliary circuit applied to a series-type 12-pulse rectifier, wherein the triple-multiplier auxiliary circuit is set on the DC side of the series-type 12-pulse rectifier and is used to multiply the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses; the series-type 12-pulse rectifier includes a phase-shifting transformer (1), a first diode rectifier bridge (2), and a second diode rectifier bridge (3); A phase-shifting transformer (1) is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by the phase-shifting transformer (1) are then sent to a first diode rectifier bridge (2) and a second diode rectifier bridge (3), respectively. Its characteristic is that... The triple-multiplier auxiliary circuit includes an auxiliary single-phase rectifier bridge (4), a four-winding auxiliary transformer (5), a balancing reactor (6), and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2; The positive output terminal of the first diode rectifier bridge (2) is connected to one end of capacitor C1 and the positive terminal of the load (7) at the same time. The negative output terminal of the second diode rectifier bridge (3) is connected to the auxiliary diode D. f1 anode, auxiliary diode D f2 The anode of the capacitor, one end of the capacitor C2, and the negative terminal of the load (7) are connected simultaneously. The positive output terminal of the auxiliary single-phase rectifier bridge (4) is connected to the negative output terminal of the first diode rectifier bridge (2), and the negative output terminal of the auxiliary single-phase rectifier bridge (4) is connected to the positive output terminal of the second diode rectifier bridge (3). The primary winding AB of the four-winding auxiliary transformer (5) is connected to the same-name terminal of its secondary winding CD, the opposite-name terminal of its secondary winding AE, and the first AC input terminal of the auxiliary single-phase rectifier bridge (4) at the same time. The secondary winding CD of the four-winding auxiliary transformer (5) is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge (4); The corresponding terminal of the secondary winding AE of the four-winding auxiliary transformer (5) is connected to the auxiliary diode D. f1 Cathode connection; The opposite-named terminal of the primary winding AB of the four-winding auxiliary transformer (5) is connected to the same-named terminal of its secondary winding BF and the center tap of the balancing reactor (6). The opposite terminal of the secondary winding BF of the four-winding auxiliary transformer (5) is connected to the auxiliary diode D. f2 Cathode connection; The same-name terminal of the balancing reactor (6) is connected to the other end of capacitor C1, and the opposite-name terminal of the balancing reactor (6) is connected to the other end of capacitor C2. Set the turns ratio of the primary and secondary windings of the four-winding auxiliary transformer (5) so that the auxiliary diode D f1 and auxiliary diode D f2 The conduction time of each is 1 / 4 of the cycle of their respective input voltage, so that the first diode rectifier bridge (2) and the second diode rectifier bridge (3) work simultaneously or alternately, and when the first diode rectifier bridge (2) and / or the second diode rectifier bridge (3) are working, the current output of their rectifier bridge is a 4-level stepped DC current of equal width, thus achieving a pulse 3 times increase.

2. The tripler auxiliary circuit applied to a series-type 12-pulse rectifier according to claim 1, characterized in that, The auxiliary single-phase rectifier bridge (4) includes diode D m1 diode D m2 diode D m3 and diode D m4 ; Diode D m1 Cathode and diode D m2 After the cathode is connected, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge (4); Diode D m3 anode and diode D m4 After the anode is connected, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge (4); Diode D m2 The anode of the diode D is simultaneously with m4 After the cathode is connected, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge (4); Diode D m1 anode and diode D m3 After the cathode is connected, it serves as the second AC input terminal of the auxiliary single-phase rectifier bridge (4).

3. The tripler auxiliary circuit for a series-type 12-pulse rectifier according to claim 2, characterized in that, The triple-multiplier auxiliary circuit includes four operating modes, specifically: Working Mode I: When u d1 >u d2 -u f1 <(u d2 -u s ) and u f2 d When / 2, diode D in the auxiliary single-phase rectifier bridge (4) m1 and diode D m4 Reverse bias cutoff, diode D m2 and diode D m3 Forward conduction; the secondary windings AE and BF of the four-winding auxiliary transformer (5) are both in a non-operating state, while the primary winding AB and secondary winding CD of the four-winding auxiliary transformer (5) are both in an operating state. The auxiliary diode D connected to the secondary winding AE of the four-winding auxiliary transformer (5) is in a forward conduction state. f1 And the auxiliary diode D connected to the secondary winding BF f2 Reverse bias cutoff; at this time, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) jointly supply power to both ends of the load (7); among which,​ u d The voltage across the load (7); u d1 The output voltage of the first diode rectifier bridge (2); u d2 The output voltage of the second diode rectifier bridge (3); u s The voltage across the secondary winding CD of the four-winding auxiliary transformer (5); u f1 The voltage across the secondary winding AE of the four-winding auxiliary transformer (5); u f2 The voltage across the secondary winding BF of the four-winding auxiliary transformer (5); Working Mode II: When u d1 >u d2 -u f1 >(u d2 -u s ) and u f2 d When / 2, diode D in the auxiliary single-phase rectifier bridge (4) m1 diode D m3 and diode D m4 Reverse bias cutoff, diode D m2 Forward conduction; the secondary windings CD and BF of the four-winding auxiliary transformer (5) are both in a non-operating state, while the primary winding AB and secondary winding AE of the four-winding auxiliary transformer (5) are both in an operating state, and the auxiliary diode D connected to the secondary winding BF is also in a working state. f2 Reverse bias cutoff, current flows through auxiliary diode D f1 current i f1 >0, current i f1 The current is injected into the negative output terminal of the first diode rectifier bridge (2). At this time, the second diode rectifier bridge (3) does not work, and its output current is zero. The first diode rectifier bridge (2) supplies power to both ends of the load (7).​ u d The voltage across the load (7); u d1 The output voltage of the first diode rectifier bridge (2); u d2 The output voltage of the second diode rectifier bridge (3); u s The voltage across the secondary winding CD of the four-winding auxiliary transformer (5); u f1 The voltage across the secondary winding AE of the four-winding auxiliary transformer (5); u f2 The voltage across the secondary winding BF of the four-winding auxiliary transformer (5); Working Mode III: When u d1 d2 -u f1 <(u d2 -u s ) and u f2 d When / 2, diode D in the auxiliary single-phase rectifier bridge (4) m2 and diode D m3 Reverse bias cutoff, diode D m1 and diode D m4 Forward conduction; the secondary windings AE and BF of the four-winding auxiliary transformer (5) are both in a non-operating state, while the primary winding AB and secondary winding CD of the four-winding auxiliary transformer (5) are both in an operating state. At the same time, the auxiliary diode D connected to the secondary winding AE of the four-winding auxiliary transformer (5) is in a working state. f1 And the auxiliary diode D connected to the secondary winding BF f2 When reverse biased and cut off, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) together supply power to both ends of the load (7); among them,​​ u d The voltage across the load (7); u d1 The output voltage of the first diode rectifier bridge (2); u d2 The output voltage of the second diode rectifier bridge (3); u s The voltage across the secondary winding CD of the four-winding auxiliary transformer (5); u f1 The voltage across the secondary winding AE of the four-winding auxiliary transformer (5); u f2 The voltage across the secondary winding BF of the four-winding auxiliary transformer (5); Working mode IV: When u d1 d2 -u f1 <(u d2 -u s ) and u f2 >u d When / 2, diode D in the auxiliary single-phase rectifier bridge (4) m1 diode D m2 and diode D m3 Reverse bias cutoff, diode D m4 Forward conduction; the secondary windings CD and AE of the four-winding auxiliary transformer (5) are both in a non-working state, while the primary winding AB and secondary winding BF of the four-winding auxiliary transformer (5) are both in a working state, and the auxiliary diode D connected to the secondary winding AE is also in a working state. f1 With reverse bias cutoff, the secondary winding BF of the four-winding auxiliary transformer (5) is in operation, and current flows through the auxiliary diode D. f2 current i f2 >0, current i f2 The current is injected into the center tap of the balancing reactor (6). At this time, the first diode rectifier bridge (2) is not working and its output current is zero. The second diode rectifier bridge (3) supplies power to both ends of the load (7).​ u d The voltage across the load (7); u d1 The output voltage of the first diode rectifier bridge (2); u d2 The output voltage of the second diode rectifier bridge (3); u s The voltage across the secondary winding CD of the four-winding auxiliary transformer (5); u f1 The voltage across the secondary winding AE of the four-winding auxiliary transformer (5); u f2 This is the voltage across the secondary winding BF of the four-winding auxiliary transformer (5).

4. A triple-multiplier auxiliary circuit applied to a series-type 12-pulse rectifier, wherein the triple-multiplier auxiliary circuit is set on the DC side of the series-type 12-pulse rectifier and is used to multiply the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses; the series-type 12-pulse rectifier includes a phase-shifting transformer (1), a first diode rectifier bridge (2), and a second diode rectifier bridge (3); A phase-shifting transformer (1) is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by the phase-shifting transformer (1) are then sent to a first diode rectifier bridge (2) and a second diode rectifier bridge (3), respectively. Its characteristic is that... The triple-boosting auxiliary circuit includes an auxiliary single-phase rectifier bridge (4), a first double-winding auxiliary transformer (5), a second double-winding auxiliary transformer (6), a triple-winding auxiliary transformer (7), and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2; The positive output terminal of the first diode rectifier bridge (2) is connected to one end of the capacitor C1 and the negative output terminal of the auxiliary single-phase rectifier bridge (4); the positive output terminal of the auxiliary single-phase rectifier bridge (4) is connected to the positive terminal of the load (8). The negative output terminal of the second diode rectifier bridge (3) is connected to the auxiliary diode D. f1 anode, auxiliary diode D f2 The anode of the capacitor, one end of the capacitor C2, and the negative terminal of the load (8) are connected simultaneously. The opposite-named terminal of the primary winding AB of the three-winding auxiliary transformer (7) is connected to the same-named terminal of its secondary winding AE, the negative output terminal of the first diode rectifier bridge (2), and the positive output terminal of the second diode rectifier bridge (3) at the same time. The opposite terminal of the secondary winding AE of the three-winding auxiliary transformer (7) is connected to the auxiliary diode D. f1 Cathode connection, The corresponding terminal of the secondary winding BF of the three-winding auxiliary transformer (7) is connected to the auxiliary diode D. f2 Cathode connection; The same-name terminal of the primary winding AB of the three-winding auxiliary transformer (7) and the opposite-name terminal of its secondary winding BF, the opposite-name terminal of the primary winding of the first double-winding auxiliary transformer (5), and the same-name terminal of the primary winding of the second double-winding auxiliary transformer (6) are connected at the same time. The same-name terminal of the primary winding of the first double-winding auxiliary transformer (5) is connected to the other end of the capacitor C1. The same-name terminal of the secondary winding of the first double-winding auxiliary transformer (5) is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge (4). The opposite-name terminal of the secondary winding of the first double-winding auxiliary transformer (5) is simultaneously connected to the opposite-name terminal of the secondary winding of the second double-winding auxiliary transformer (6). The opposite end of the primary winding of the second double-winding auxiliary transformer (6) is connected to the other end of the capacitor C2, and the same end of the secondary winding of the second double-winding auxiliary transformer (6) is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge (4). Set the turns ratio of the primary and secondary windings of the first double-winding auxiliary transformer (5), the second double-winding auxiliary transformer (6), and the three-winding auxiliary transformer (7) so that the auxiliary diode D f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle, so that the first diode rectifier bridge (2) and the second diode rectifier bridge (3) work simultaneously, thereby realizing the tripler auxiliary circuit to triple the pulse number.

5. The tripler auxiliary circuit for a series-type 12-pulse rectifier according to claim 4, characterized in that, The auxiliary single-phase rectifier bridge (4) includes diodes D1, D2, D3 and D4; After the cathode of diode D1 is connected to the anode of diode D3, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge (4); After the cathode of diode D2 and the anode of diode D4 are connected, they serve as the second AC input terminal of the auxiliary single-phase rectifier bridge (4); After the anode of diode D1 is connected to the anode of diode D2, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge (4); After the cathode of diode D3 is connected to the cathode of diode D4, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge (4).

6. The tripler auxiliary circuit for a series-type 12-pulse rectifier according to claim 5, characterized in that, The triple-multiplier auxiliary circuit includes three operating modes, specifically: Working Mode I: When u f1 d2 and-u f2 <(u d2 +u o When the first double-winding auxiliary transformer (5), the second double-winding auxiliary transformer (6), the three-winding auxiliary transformer (7), and the auxiliary diode D are in operation, the auxiliary transformer (5) is in operation. f1 and auxiliary diode D f2 Both capacitors C1 and C2 are in a non-operating state. At this time, the output currents of the first diode rectifier bridge (2) and the second diode rectifier bridge (3) are equal, and the load (8) is powered through the auxiliary single-phase rectifier bridge (4);​ u d1 The output voltage of the first diode rectifier bridge (2); u d2 The output voltage of the second diode rectifier bridge (3); u f1 The voltage across the secondary winding AE of the three-winding auxiliary transformer (7); u f2 The voltage across the secondary winding BF of the three-winding auxiliary transformer (7); u o The voltage across the primary winding AB of the three-winding auxiliary transformer (7); Working Mode II: When u f1 >u d2 At that time, the primary winding AB and the secondary winding AE of the three-winding auxiliary transformer (7) are both in operation, and the auxiliary diode D connected to the secondary winding AE is also in operation. f1 Forward conduction, current flows through auxiliary diode D f1 current i f1 >0, current i f1 Injected into the negative output terminal of the first diode rectifier bridge (2); the secondary winding BF of the three-winding auxiliary transformer (7) is in a non-working state, and the auxiliary diode D connected to the secondary winding BF of the three-winding auxiliary transformer (7) is in a non-working state. f2 When reverse-biased and cut off, diodes D1 and D4 in the auxiliary single-phase rectifier bridge (4) are reverse-biased and cut off, while diodes D2 and D3 are forward-biased and conduct. At this time, the output current of the first diode rectifier bridge (2) is greater than the output current of the second diode rectifier bridge (3), and diodes D2 and D3 in the auxiliary single-phase rectifier bridge (4) jointly supply power to both ends of the load (8); among which, u f1 The voltage across the secondary winding AE of the three-winding auxiliary transformer (7); u d2 The output voltage of the second diode rectifier bridge (3); Working Mode III: When -u f2 >(u d2 +u o When the primary winding AB and secondary winding BF of the three-winding auxiliary transformer (7) are both in operation, the auxiliary diode D connected to the secondary winding BF is also in operation. f2 Forward conduction, current flows through auxiliary diode D f2 current i f2 >0; The secondary winding AE of the three-winding auxiliary transformer (7) is in a non-working state, and the auxiliary diode D connected to the secondary winding AE of the three-winding auxiliary transformer (7) is in a non-working state. f1 When reverse-biased and cut off, diodes D2 and D3 in the auxiliary single-phase rectifier bridge (4) are reverse-biased and cut off, while diodes D1 and D4 are forward-biased and conduct. At this time, the output current of the first diode rectifier bridge (2) is less than the output current of the second diode rectifier bridge (3), and diodes D1 and D4 in the auxiliary single-phase rectifier bridge (4) jointly supply power to both ends of the load (8); among which, u d2 The output voltage of the second diode rectifier bridge (3); u f2 The voltage across the secondary winding BF of the three-winding auxiliary transformer (7); u o This is the voltage across the primary winding AB of the three-winding auxiliary transformer (7).

7. A triple-multiplier auxiliary circuit applied to a series-type 12-pulse rectifier, wherein the triple-multiplier auxiliary circuit is set on the DC side of the series-type 12-pulse rectifier and is used to multiply the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses; the series-type 12-pulse rectifier includes a phase-shifting transformer (1), a first diode rectifier bridge (2), and a second diode rectifier bridge (3); A phase-shifting transformer (1) is used to shift the three-phase voltage input from the power grid to generate two three-phase voltages with a phase difference of 30° and the same amplitude. The two three-phase voltages generated by the phase-shifting transformer (1) are then sent to a first diode rectifier bridge (2) and a second diode rectifier bridge (3), respectively. Its characteristic is that... The triple-enhancing auxiliary circuit includes an auxiliary single-phase rectifier bridge (4), a first double-winding auxiliary transformer (5), a second double-winding auxiliary transformer (6), a third double-winding auxiliary transformer (7), and an auxiliary diode D. f1 and auxiliary diode D f2 Capacitors C1 and C2; The positive output terminal of the first diode rectifier bridge (2) is connected to one end of capacitor C1 and the negative output terminal of the auxiliary single-phase rectifier bridge (4). The positive output terminal of the auxiliary single-phase rectifier bridge (4) is connected to the auxiliary diode D. f1 The cathode and the positive terminal of the load (8) are connected simultaneously; The negative output terminal of the second diode rectifier bridge (3) is connected to one end of capacitor C2 and auxiliary diode D. f2 The anode and the negative terminal of the load (8) are connected simultaneously; The opposite-named terminal of the primary winding AB of the first double-winding auxiliary transformer (5) is simultaneously connected to the negative output terminal of the first diode rectifier bridge (2) and the positive output terminal of the second diode rectifier bridge (3). The same-name terminal of the primary winding AB of the first double-winding auxiliary transformer (5) and the opposite-name terminal of its secondary winding CD, the opposite-name terminal of the primary winding of the second double-winding auxiliary transformer (6), and the same-name terminal of the primary winding of the third double-winding auxiliary transformer (7) are connected simultaneously. The same-name terminal of the primary winding of the second double-winding auxiliary transformer (6) is connected to the other end of the capacitor C1. The same-name terminal of the secondary winding of the second double-winding auxiliary transformer (6) is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge (4). The opposite-name terminal of the secondary winding of the second double-winding auxiliary transformer (6) is connected to the opposite-name terminal of the secondary winding of the third double-winding auxiliary transformer (7). The opposite end of the primary winding of the third double-winding auxiliary transformer (7) is connected to the other end of the capacitor C2, and the same end of the secondary winding of the third double-winding auxiliary transformer (7) is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge (4). The corresponding terminal of the secondary winding CD of the first double-winding auxiliary transformer (5) is connected to the auxiliary diode D. f1 anode and auxiliary diode D f2 The cathodes are connected simultaneously; By setting the turns ratio of the primary and secondary windings of the first double-winding auxiliary transformer (5), the second double-winding auxiliary transformer (6), and the third double-winding auxiliary transformer (7), the auxiliary diode D is made to... f1 and auxiliary diode D f2 The conduction time of each diode is 1 / 3 of its respective input voltage cycle, so that the first diode rectifier bridge (2) and the second diode rectifier bridge (3) work simultaneously, thereby realizing the triple-multiplier auxiliary circuit to multiply the pulse number by 3 times.

8. The tripler auxiliary circuit for a series-type 12-pulse rectifier according to claim 7, characterized in that, The auxiliary single-phase rectifier bridge (4) includes diodes D1, D2, D3 and D4; After the anode of diode D2 is connected to the cathode of diode D4, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge (4); After the anode of diode D1 and the cathode of diode D3 are connected, they serve as the second AC input terminal of the auxiliary single-phase rectifier bridge (4); After the anode of diode D3 is connected to the anode of diode D4, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge (4); After the cathode of diode D1 is connected to the cathode of diode D2, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge (4).

9. The tripler auxiliary circuit for a series-type 12-pulse rectifier according to claim 8, characterized in that, The triple-multiplier auxiliary circuit includes three operating modes, specifically: Working Mode I: When u f <(u d1 -u o ) and -u f <(u d2 +u o When the first double-winding auxiliary transformer (5), the second double-winding auxiliary transformer (6), the third double-winding auxiliary transformer (7), and the auxiliary diode D are in operation, the auxiliary transformer (5) is in operation. f1 and auxiliary diode D f22 Both are in a non-operating state. At this time, the output currents of the first diode rectifier bridge (2) and the second diode rectifier bridge (3) are equal, and all diodes in the auxiliary single-phase rectifier bridge (4) supply power to the two ends of the load (8); among them, u d1 The output voltage of the first diode rectifier bridge (2); u d2 The output voltage of the second diode rectifier bridge (3); u o The voltage across the primary winding AB of the first double-winding auxiliary transformer (5); u f The voltage across the secondary winding CD of the first double-winding auxiliary transformer (5); Working Mode II: When u f >(u d1 -u o At this time, the first double-winding auxiliary transformer (5), the second double-winding auxiliary transformer (6), and the third double-winding auxiliary transformer (7) are all in operation, and the auxiliary diode D is connected to the secondary winding CD of the first double-winding auxiliary transformer (5). f1 Forward conduction, current flows through auxiliary diode D f1 current i f1 >0, auxiliary diode D f2 Reverse bias cutoff; in the auxiliary single-phase rectifier bridge (4), diodes D1 and D4 are reverse biased and cut off, while diodes D2 and D3 are forward biased and conduction-through. At this time, the output current of the first diode rectifier bridge (2) is greater than the output current of the second diode rectifier bridge (3), and diodes D2 and D3 in the auxiliary single-phase rectifier bridge (4) jointly supply power to both ends of the load (8); among which, u d1 The output voltage of the first diode rectifier bridge (2); u o The voltage across the primary winding AB of the first double-winding auxiliary transformer (5); u f The voltage across the secondary winding CD of the first double-winding auxiliary transformer (5); Working Mode III: When -u f >(u d2 +u o At this time, the first double-winding auxiliary transformer (5), the second double-winding auxiliary transformer (6), and the third double-winding auxiliary transformer (7) are all in operation, and the auxiliary diode D is connected to the secondary winding CD of the first double-winding auxiliary transformer (5). f2 Forward conduction, current flows through auxiliary diode D f2 current i f2 >0, auxiliary diode D f1 Reverse bias cutoff; in the auxiliary single-phase rectifier bridge (4), diodes D2 and D3 are reverse biased and cut off, while diodes D1 and D4 are forward biased and conduction-through. At this time, the output current of the first diode rectifier bridge (2) is less than the output current of the second diode rectifier bridge (3), and diodes D1 and D4 in the auxiliary single-phase rectifier bridge (4) jointly supply power to both ends of the load (8). u d2 The output voltage of the second diode rectifier bridge (3); u o The voltage across the primary winding AB of the first double-winding auxiliary transformer (5); u f This is the voltage across the secondary winding CD of the first double-winding auxiliary transformer (5).

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