Series type 36-pulse rectifier with voltage doubling rectifying pulse multiplication circuit

Abstract

This invention relates to a series-type 36-pulse rectifier with a voltage multiplier pulse multiplier circuit, belonging to the field of power electronics technology. It solves the problem of existing 12-pulse rectifiers that increase the pulse count by adding an auxiliary pulse multiplier circuit. This method suffers from drawbacks such as a large turns ratio between the secondary and primary windings of the auxiliary transformer in the auxiliary pulse multiplier circuit, leading to increased leakage inductance, reduced harmonic suppression, higher input current harmonics, and increased manufacturing difficulty. This invention adds a voltage multiplier pulse multiplier circuit to the DC side of a conventional series-type 12-pulse rectifier. By adjusting the turns ratio of the primary and secondary windings of the auxiliary transformer, it modulates and increases the number of states of the output current and voltage of the first and second diode rectifier bridges. Based on the AC and DC current and voltage relationships of the 12-pulse rectifier, the pulse count is increased to three times the original value. This invention is primarily used for pulse multiplication.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a series-type 36-pulse rectifier with a voltage multiplier pulse multiplier stage. Background Technology

[0002] 12-pulse rectifiers, with their simple structure, high reliability, and strong overload capacity, are widely used as interface circuits between high-power electrical equipment and the power grid in high-power industrial applications such as ship electric propulsion, hydrogen electrolysis, offshore wind power generation, and electric aircraft power supply. However, with the continuous increase in the capacity of industrial equipment and the increasing performance requirements of high-power electrical equipment, the harmonic suppression capability of conventional 12-pulse rectifiers can no longer meet the requirements of industrial applications. Under inductive load conditions, the input current THD of conventional 12-pulse rectifiers is greater than 10%, which cannot meet the requirements of harmonic standards such as IEEE-519 and IEC-16, and will cause harmonic pollution to the power grid. In high-power industrial applications, the harmonic pollution generated by 12-pulse rectifiers is even more serious. To effectively suppress the input current harmonics of series-type 12-pulse rectifiers, various methods have been proposed, among which increasing the pulse number of the rectifier is one of the most important and effective methods. Currently, there are two main methods for increasing the pulse number of series-type 12-pulse rectifiers:

[0003] The first approach involves increasing the number of secondary windings in the phase-shifting transformer and using multiple connections in the three-phase rectifier bridge to multiply the rectifier's pulse count to 24, 30, or 36, thereby suppressing harmonics in the grid-side input current and ripple in the output voltage. However, as the rectifier pulse count increases, the number of secondary output windings in the phase-shifting transformer also increases exponentially. This not only increases the manufacturing difficulty of the phase-shifting transformer but also makes it difficult to ensure the symmetry between the windings, leading to non-characteristic subharmonics in the rectifier's input current. Furthermore, the cost of the rectifier's components also increases, resulting in a larger, heavier, and more expensive rectifier.

[0004] The second approach involves adding an auxiliary pulse multiplier circuit to the DC side of the rectifier to increase the pulse count and reduce the input current harmonics. However, the auxiliary transformer in the pulse multiplier circuit introduced on the DC side has a large turns ratio between the secondary and primary sides, which results in a large leakage inductance in the transformer, reducing the harmonic suppression effect. Consequently, the input current harmonics of the rectifier remain relatively high. At the same time, a large turns ratio also increases the manufacturing difficulty of the transformer. Therefore, these problems urgently need to be solved. Summary of the Invention

[0005] The purpose of this invention is to address the problem that existing 12-pulse rectifiers, which increase the pulse count by adding an auxiliary pulse multiplier circuit, suffer from several drawbacks. Firstly, the auxiliary transformer in the auxiliary pulse multiplier circuit has a large turns ratio between the secondary and primary sides, leading to increased leakage inductance, reduced harmonic suppression, higher input current harmonics, and increased manufacturing difficulty. This invention provides two series-connected 36-pulse rectifiers with voltage multiplier pulse multiplier circuits.

[0006] First structure:

[0007] A series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit includes a series-type 12-pulse rectifier and a voltage multiplier rectifier pulse multiplier circuit; the series-type 12-pulse rectifier includes a phase-shifting transformer, a first diode rectifier bridge and a second diode rectifier bridge.

[0008] 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 output to the first diode rectifier bridge and the second diode rectifier bridge, respectively.

[0009] The voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge and the second rectifier bridge, thereby multiplying the 12 pulses of the series 12-pulse rectifier by 3 times to obtain 36 pulses.

[0010] The voltage multiplier rectifier pulse multiplier circuit includes an auxiliary single-phase rectifier bridge, a multi-winding auxiliary transformer, a voltage multiplier rectifier, a balancing reactor with a center tap, capacitor C1, and capacitor C2.

[0011] After the positive output terminal of the first diode rectifier bridge is connected to one end of capacitor C1, it is connected to the positive output terminal of the series 36-pulse rectifier and the positive input terminal of the load.

[0012] After the negative output terminal of the second diode rectifier bridge is connected to one end of capacitor C2 and the DC input terminal of the voltage multiplier rectifier, it is connected to the negative output terminal of the series 36-pulse rectifier and the negative input terminal of the load.

[0013] 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.

[0014] The primary winding AB of the multi-winding auxiliary transformer is connected to the same-name terminal A and the secondary winding CD, the opposite-name terminal D, the first AC input terminal of the auxiliary single-phase rectifier bridge, and the DC output terminal of the voltage multiplier rectifier.

[0015] The opposite-name terminal B of the primary winding AB of the multi-winding auxiliary transformer is connected to the center tap of the balancing reactor with a center tap.

[0016] The corresponding terminal C of the secondary winding CD of the multi-winding auxiliary transformer is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge;

[0017] The same-name terminal E of the secondary winding EF of the multi-winding auxiliary transformer is connected to the first AC input terminal of the voltage multiplier rectifier, and the opposite-name terminal F of the secondary winding EF of the multi-winding auxiliary transformer is connected to the second AC input terminal of the voltage multiplier rectifier.

[0018] The same-name terminal of the center-tapped balancing reactor is connected to the other end of capacitor C1, and the opposite-name terminal of the center-tapped balancing reactor is connected to the other end of capacitor C2.

[0019] By setting the turns ratio of the primary and secondary windings of the multi-winding auxiliary transformer, the conduction time of the diodes in the voltage multiplier rectifier is made to be 1 / 6 of the voltage cycle received between the two AC input terminals of the voltage multiplier rectifier. This allows the first diode rectifier bridge and the second diode rectifier bridge to work simultaneously, and the output currents of the first diode rectifier bridge and the second diode rectifier bridge are both four-level stepped DC currents of equal width. The output voltages of the first diode rectifier bridge and the second diode rectifier bridge are both six-pulse DC voltages of equal width.

[0020] The second structure:

[0021] A series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit includes a series-type 12-pulse rectifier and a voltage multiplier rectifier pulse multiplier circuit; the series-type 12-pulse rectifier includes a phase-shifting transformer, a first diode rectifier bridge and a second diode rectifier bridge.

[0022] 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 output to the first diode rectifier bridge and the second diode rectifier bridge, respectively.

[0023] The voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge and the second rectifier bridge, thereby multiplying the 12 pulses of the series 12-pulse rectifier by 3 times to obtain 36 pulses.

[0024] The voltage multiplier rectifier pulse multiplier circuit includes a voltage multiplier rectifier, a first single-phase auxiliary transformer, a second single-phase auxiliary transformer, a third single-phase auxiliary transformer, an auxiliary single-phase rectifier bridge, capacitor C1, and capacitor C2;

[0025] 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 input terminal of the load as the positive output terminal of the series 36-pulse rectifier.

[0026] After the negative output terminal of the second diode rectifier bridge is connected to one end of capacitor C2 and the DC input terminal of the voltage multiplier rectifier, it is connected to the negative output terminal of the series 36-pulse rectifier and the negative input terminal of the load.

[0027] The DC output terminal of the voltage multiplier rectifier is simultaneously connected to the same-name terminal A of the primary winding AB of the first single-phase auxiliary transformer, the negative output terminal of the first diode rectifier bridge, and the positive output terminal of the second diode rectifier bridge.

[0028] The opposite-named terminal B of the primary winding AB of the first single-phase auxiliary transformer is simultaneously connected to the opposite-named terminal F of the primary winding EF of the second single-phase auxiliary transformer and the same-named terminal L of the primary winding LK of the third single-phase auxiliary transformer.

[0029] The same-name terminal C and opposite-name terminal D of the secondary winding CD of the first single-phase auxiliary transformer are connected to the first and second AC input terminals of the voltage multiplier rectifier, respectively.

[0030] The same-name terminal E of the primary winding EF of the second single-phase auxiliary transformer is connected to the other end of the capacitor C1. The same-name terminal H of the secondary winding HG of the second single-phase auxiliary transformer is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge. The opposite-name terminal G of the secondary winding HG of the second single-phase auxiliary transformer is connected to the opposite-name terminal I of the secondary winding IJ of the third single-phase auxiliary transformer.

[0031] The opposite-name terminal K of the primary winding LK of the third single-phase auxiliary transformer is connected to the other end of the capacitor C2, and the same-name terminal J of the secondary winding IJ of the third single-phase auxiliary transformer is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge.

[0032] By setting the turns ratio of the primary and secondary windings of the first, second, and third single-phase auxiliary transformers, the conduction time of the diodes in the voltage multiplier rectifier is made to be 1 / 3 of the voltage cycle received between the two AC input terminals of the voltage multiplier rectifier. This allows the first and second diode rectifier bridges to operate simultaneously, and the output currents of both the first and second diode rectifier bridges are non-equal-width three-level stepped DC currents. The output voltages of both the first and second diode rectifier bridges are equal-width six-pulse DC voltages.

[0033] The beneficial effects of this invention are:

[0034] This invention provides two types of series-type 36-pulse rectifiers with low-turn-ratio passive pulse multiplier circuits on the DC side. These rectifiers offer advantages such as simple circuit structure, ease of production, high reliability, and low cost. They only require adding a low-turn-ratio passive pulse multiplier circuit to the DC side of a series-type 12-pulse rectifier to modulate the state numbers of the output current and output voltage of the first diode rectifier bridge and the second diode rectifier bridge, thereby multiplying the 12 pulses of the series-type 12-pulse rectifier by a factor of 3. By employing a voltage multiplier rectifier, the turns ratio between the primary and secondary windings of the auxiliary transformer is significantly reduced, lowering the processing difficulty and simplifying the manufacturing process of the auxiliary transformer. This effectively suppresses the input current harmonic content and output voltage ripple of the series-type 12-pulse rectifier, ensuring that the input current THD of the rectifier meets the requirements of most industrial applications.

[0035] The series-type 36-pulse rectifier with a low turns ratio passive pulse multiplier circuit on the DC side described in this invention eliminates the need for a series inductor on the input side of the 12-pulse rectifier, thus avoiding the problem of needing a large inductor on the AC side of the 12-pulse rectifier when using an auxiliary voltage injection circuit. This allows the rectifier to obtain a higher displacement factor and a stable output voltage, making it more promising for medium- and high-voltage high-power applications. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the first structure of the series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit as described in Specific Implementation Method 1.

[0037] Figure 2 This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 1 when it is operating in Mode I.

[0038] Figure 3 This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 1 when it is operating in Mode II.

[0039] Figure 4 This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 1 when it is operating in Mode III.

[0040] Figure 5 This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 1 when it is operating in Mode IV.

[0041] Figure 6 This is a schematic diagram of the second structure of the series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit as described in Specific Implementation Method 5.

[0042] Figure 7This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 5 when it is operating in Mode I;

[0043] Figure 8 This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 5 when it is operating in Mode II.

[0044] Figure 9 This is a schematic diagram of the current loop of the voltage multiplier rectifier pulse multiplier circuit described in Specific Implementation Method 5 when it is operating in Mode III.

[0045] in, Figures 1 to 9 middle,

[0046] i A i B i C These are the three-phase input currents a, b, and c of phase-shifting transformer 1, respectively.

[0047] 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;

[0048] 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.

[0049] 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.

[0050] i c1 i c2 These are the currents flowing through capacitor C1 and capacitor C2, respectively;

[0051] i d1 This is the current output from the positive terminal of the first diode rectifier bridge 2;

[0052] i d2 This is the current input to the negative terminal of the second diode rectifier bridge 3;

[0053] i d This refers to the current input to the positive terminal of the load.

[0054] u d1 This is the output voltage of the first diode rectifier bridge 2;

[0055] u d2 This is the output voltage of the second diode rectifier bridge 3;

[0056] Figures 1 to 5 middle,

[0057] i d3 The current input from the opposite terminal B of the primary winding of the multi-winding auxiliary transformer 5 to the center tap of the balancing reactor 7;

[0058] u p This is the voltage across the primary winding AB of the multi-winding auxiliary transformer 5;

[0059] u s1 This is the voltage across the secondary winding EF of the multi-winding auxiliary transformer 5;

[0060] u s2 This is the voltage across the secondary winding CD of the multi-winding auxiliary transformer 5;

[0061] i s This refers to the current flowing into the DC output terminal of the voltage multiplier rectifier 6;

[0062] in, Figures 6 to 9 middle,

[0063] i d3 The current flowing from the junction of the opposite-name terminal F of the primary winding EF of the second single-phase auxiliary transformer 6 and the same-name terminal LK of the primary winding of the third single-phase auxiliary transformer 7 into the primary winding AB of the first single-phase auxiliary transformer 5.

[0064] u p1 This is the voltage across the primary winding AB of the first single-phase auxiliary transformer 5;

[0065] u s1 This is the voltage across the secondary winding CD of the first single-phase auxiliary transformer 5;

[0066] u p2 This is the voltage across the primary winding EF of the second single-phase auxiliary transformer 6;

[0067] u s2 This is the voltage across the secondary winding HG of the second single-phase auxiliary transformer 6;

[0068] u p3 This is the voltage across the primary winding LK of the third single-phase auxiliary transformer 7;

[0069] u s3 This refers to the voltage across the secondary winding IJ of the third single-phase auxiliary transformer 7.

[0070] i s1 This is the current flowing into the DC input terminal of the voltage multiplier rectifier 4. Detailed Implementation

[0071] 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.

[0072] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0073] This invention provides two types of series-type 36-pulse rectifiers with voltage multiplier rectifier pulse multiplier circuits, and the two structures are respectively described in [reference 1]. Figure 1 and Figure 6 Among them, the first type of 36-pulse rectifier, specifically... Figures 1 to 5 The second type of 36-pulse rectifier, see details below. Figures 6 to 9 The details are as follows:

[0074] Specific Implementation Method 1: The following is combined with... Figure 1 This embodiment describes a series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit in the first structure of this embodiment, which includes a series-type 12-pulse rectifier and a voltage multiplier rectifier pulse multiplier circuit; 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.

[0075] 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 output to the first diode rectifier bridge 2 and the second diode rectifier bridge 3, respectively.

[0076] The voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge 2 and the second rectifier bridge 3, thereby multiplying the 12 pulses of the series 12-pulse rectifier by 3 times to obtain 36 pulses.

[0077] The voltage multiplier rectifier pulse multiplier circuit includes an auxiliary single-phase rectifier bridge 4, a multi-winding auxiliary transformer 5, a voltage multiplier rectifier 6, a balancing reactor with a center tap 7, capacitor C1, and capacitor C2.

[0078] After the positive output terminal of the first diode rectifier bridge 2 is connected to one end of the capacitor C1, it is connected to the positive output terminal of the series 36-pulse rectifier and the positive input terminal of the load 8.

[0079] After the negative output terminal of the second diode rectifier bridge 3 is connected to one end of capacitor C2 and the DC input terminal of voltage multiplier rectifier 6, it is connected to the negative output terminal of series 36-pulse rectifier and the negative input terminal of load 8.

[0080] 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.

[0081] The same-name terminal A of the primary winding AB of the multi-winding auxiliary transformer 5 and the opposite-name terminal D of its secondary winding CD, the first AC input terminal of the auxiliary single-phase rectifier bridge 4, and the DC output terminal of the voltage multiplier rectifier 6 are connected simultaneously.

[0082] The opposite-name terminal B of the primary winding AB of the multi-winding auxiliary transformer 5 is connected to the center tap of the balancing reactor 7 with a center tap.

[0083] The secondary winding CD of the multi-winding auxiliary transformer 5 is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge 4.

[0084] The same-name terminal E of the secondary winding EF of the multi-winding auxiliary transformer 5 is connected to the first AC input terminal of the voltage multiplier rectifier 6, and the opposite-name terminal F of the secondary winding EF of the multi-winding auxiliary transformer 5 is connected to the second AC input terminal of the voltage multiplier rectifier 6.

[0085] The same-name terminal of the center-tapped balancing reactor 7 is connected to the other end of capacitor C1, and the opposite-name terminal of the center-tapped balancing reactor 7 is connected to the other end of capacitor C2.

[0086] By setting the turns ratio of the primary and secondary windings of the multi-winding auxiliary transformer 5, the conduction time of the diodes in the voltage multiplier rectifier 6 is made to be 1 / 6 of the voltage cycle received between the two AC input terminals of the voltage multiplier rectifier 6. This allows the first diode rectifier bridge 2 and the second diode rectifier bridge 3 to work simultaneously, and the output currents of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both four-level stepped DC currents of equal width, and the output voltages of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both six-pulse DC voltages of equal width.

[0087] 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.

[0088] In this embodiment, the voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series-type 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge 2 and the second rectifier bridge 3, thereby multiplying the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses. The implementation method is as follows: the first diode rectifier bridge 2 and the second rectifier bridge 3 work simultaneously, and the output current of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both four-level stepped DC currents of equal width, and the output voltage of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both six-pulse DC voltages of equal width, thereby multiplying the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses.

[0089] In this embodiment, the equal-width four-level stepped DC current refers to: four different current states within one cycle, and the current value output by the rectifier bridge is constant under the same current state. "Equal width" means that the duration of each current state is the same. The equal-width six-pulse DC voltage refers to: six pulses of the output voltage of the rectifier bridge within one cycle, and the duration of each pulse is the same.

[0090] In this embodiment, the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit can achieve a 3-fold increase in the number of rectifier pulses without using a phase-shifting voltage transformer with multi-phase output windings and any active switching devices. Compared with the existing 36-pulse rectifier obtained through phase-shifting multiple connections, it has the advantages of simple circuit structure, easy implementation and low cost.

[0091] In this embodiment, the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit of the present invention does not require an inductor to be connected in series on the input side of the 12-pulse rectifier. This avoids the problem of needing to connect a large inductor in series on the AC side of the 12-pulse rectifier when using an auxiliary voltage injection circuit, enabling the rectifier to obtain a higher displacement factor and a stable output voltage, and has better application prospects in medium- and high-voltage high-power applications.

[0092] In this embodiment, the voltage multiplier rectifier 6 is used to multiply the number of its own output voltage pulses.

[0093] Specific Implementation Method Two: The following is combined with... Figure 1 This embodiment further explains the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit described in Embodiment 1. The overall structure consisting of the primary winding AB and its secondary winding EF of the multi-winding auxiliary transformer 5, and the voltage multiplier rectifier 6, is used to multiply the number of current levels flowing into the isolation transformer 1.

[0094] Specific Implementation Method Three: The following is combined with... Figure 1This embodiment further describes the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit described in Embodiment 1. The auxiliary single-phase rectifier bridge 4 includes diode D. m1 Diode D m2 Diode D m3 and diode D m4 ;

[0095] Diode D m2 anode and diode D m4 After the cathode is connected, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge 4;

[0096] 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;

[0097] Diode D m1 Cathode and diode D m2 After the cathode is connected, 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.

[0098] Diode D m3 anode and diode D m4 After the anode is connected, 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.

[0099] The voltage multiplier rectifier 6 includes a diode D. n1 Diode D n2 Capacitors C3 and C4;

[0100] Diode D n1 After the cathode is connected to one end of capacitor C3, it serves as the DC output terminal of voltage multiplier rectifier 6.

[0101] Diode D n2 After the anode of the capacitor is connected to one end of the capacitor C4, it serves as the DC input terminal of the voltage multiplier rectifier 6.

[0102] After the other end of capacitor C3 is connected to the other end of capacitor C4, it serves as the first AC input terminal of voltage multiplier rectifier 6.

[0103] Diode D n1 anode and diode D n2 After the cathode is connected, it serves as the second AC input terminal of the voltage multiplier rectifier 6.

[0104] In this preferred embodiment, the structure of the voltage multiplier rectifier 6 and the auxiliary single-phase rectifier bridge 4 is shown, which is simple and easy to implement.

[0105] Specific Implementation Method Four: The following is combined with... Figures 2 to 5 This embodiment further explains the series-type 36-pulse rectifier with a voltage doubler rectifier pulse multiplier circuit described in Embodiment 3. The voltage doubler rectifier pulse multiplier circuit includes four operating modes, specifically:

[0106] Working Mode I: See Figure 2 , when |u s1 | d2 , and u s2 When >0, 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 winding EF of the multi-winding auxiliary transformer 5 is in a non-operating state, and the two diodes D in the voltage multiplier rectifier 6 are in a forward conduction state. n1 and D n2 When reverse biased and cut off, no current flows through capacitors C3 and C4. 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 8.

[0107] Working Mode II: See Figure 3 , when u s1< u d2 +u s2 , and u s2 When <0, 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 winding EF of the multi-winding auxiliary transformer 5 is in a non-operating state, and the two diodes D in the voltage multiplier rectifier 6 are in a forward conduction state. n1 and D n2 All are reverse-biased and cut off, so no current flows through the capacitors. 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 8.

[0108] Working Mode III: See Figure 4 , when u s2 <0 and -u s1 >u d2 -u s2 At that time, 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; diode D in voltage multiplier rectifier 6 n1 Forward guidance, D n2 ​When reverse cutoff occurs, the current flowing through capacitors C3 and C4 in voltage multiplier rectifier 6 enters the E terminal of the secondary winding EF of multi-winding auxiliary transformer 5. At this time, the first diode rectifier bridge 2 and the second diode rectifier bridge 3 supply power to both ends of load 8.

[0109] Working Mode IV: See Figure 5 , when -u s1 >u d2 andu s2 When >0, diode D in auxiliary single-phase rectifier bridge 4 m1 diode D m4 Forward conduction, diode D m2 and diode D m3 Reverse bias cutoff; diode D in voltage multiplier rectifier 6 n1 Reverse cutoff, diode D n2 Forward conduction, current i s Through diode D n2 The current flows to capacitors C3 and C4. 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 8.

[0110] i s This is the current flowing through the voltage multiplier rectifier 6.

[0111] In this preferred embodiment, four operating modes of the voltage multiplier rectifier pulse multiplier circuit in the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit of the first structure are given, and the operating status of each component in each mode is described in detail.

[0112] Principle Analysis:

[0113] This invention is in Figure 1 In the circuit structure shown (i.e., the first structure of the present invention, a series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit), a voltage multiplier rectifier pulse multiplier circuit is added to the DC side of a conventional series-type 12-pulse rectifier to modulate and increase the number of states of the output current and output voltage of the first diode rectifier bridge 2 and the second diode rectifier bridge 3. By designing the turns ratio of the primary and secondary windings of the multi-winding auxiliary transformer 5, the conduction time of each diode in the voltage multiplier rectifier 6 is one-sixth of its input voltage period. The output currents of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are four-level DC currents of equal width. The output voltages of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are six-pulse DC voltages of equal width. Based on the AC / DC side voltage and AC / DC side current relationship of the 12-pulse rectifier, the pulse number of the 12-pulse rectifier is increased to 3 times the original, that is, from 12 pulses to 36 pulses. This effectively suppresses the input current harmonics and output voltage pulsation of the 12-pulse rectifier without significantly increasing the complexity of the rectifier.

[0114] Specific Implementation Method Five: The following is combined with... Figure 6 This embodiment describes a second type of series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit, which includes a series-type 12-pulse rectifier and a voltage multiplier rectifier pulse multiplier circuit. 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.

[0115] 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 output to the first diode rectifier bridge 2 and the second diode rectifier bridge 3, respectively.

[0116] The voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge 2 and the second rectifier bridge 3, thereby multiplying the 12 pulses of the series 12-pulse rectifier by 3 times to obtain 36 pulses.

[0117] The voltage multiplier rectifier pulse multiplier circuit includes a voltage multiplier rectifier 4, a first single-phase auxiliary transformer 5, a second single-phase auxiliary transformer 6, a third single-phase auxiliary transformer 7, an auxiliary single-phase rectifier bridge 8, capacitor C1, and capacitor C2.

[0118] 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 8. The positive output terminal of the auxiliary single-phase rectifier bridge 8 is connected to the positive input terminal of the load 9 as the positive output terminal of the series 36-pulse rectifier.

[0119] After the negative output terminal of the second diode rectifier bridge 3 is connected to one end of capacitor C2 and the DC input terminal of voltage multiplier rectifier 4, it is connected to the negative output terminal of the series 36-pulse rectifier and the negative input terminal of load 9.

[0120] The DC output terminal of the voltage multiplier rectifier 4 is simultaneously connected to the same-name terminal A of the primary winding AB of the first single-phase auxiliary transformer 5, the negative output terminal of the first diode rectifier bridge 2, and the positive output terminal of the second diode rectifier bridge 3.

[0121] The opposite-named terminal B of the primary winding AB of the first single-phase auxiliary transformer 5 is simultaneously connected to the opposite-named terminal F of the primary winding EF of the second single-phase auxiliary transformer 6 and the same-named terminal L of the primary winding LK of the third single-phase auxiliary transformer 7.

[0122] The same-name terminal C and opposite-name terminal D of the secondary winding CD of the first single-phase auxiliary transformer 5 are connected to the first and second AC input terminals of the voltage multiplier rectifier 4, respectively.

[0123] The same-name terminal E of the primary winding EF of the second single-phase auxiliary transformer 6 is connected to the other end of the capacitor C1. The same-name terminal H of the secondary winding HG of the second single-phase auxiliary transformer 6 is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge 8. The opposite-name terminal G of the secondary winding HG of the second single-phase auxiliary transformer 6 is connected to the opposite-name terminal I of the secondary winding IJ of the third single-phase auxiliary transformer 7.

[0124] The opposite-name terminal K of the primary winding LK of the third single-phase auxiliary transformer 7 is connected to the other end of the capacitor C2, and the same-name terminal J of the secondary winding IJ of the third single-phase auxiliary transformer 7 is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge 8.

[0125] By setting the turns ratio of the primary and secondary windings of the first single-phase auxiliary transformer 5, the second single-phase auxiliary transformer 6, and the third single-phase auxiliary transformer 7, the conduction time of the diodes in the voltage multiplier rectifier 4 is made to be 1 / 3 of the voltage cycle received between the two AC input terminals of the voltage multiplier rectifier 4. This allows the first diode rectifier bridge 2 and the second diode rectifier bridge 3 to work simultaneously, and the output currents of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both non-equal width three-level stepped DC currents. The output voltages of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both equal width six-pulse DC voltages.

[0126] 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.

[0127] In this embodiment, the voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series-type 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge 2 and the second rectifier bridge 3, thereby multiplying the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses. The implementation method is as follows: the first diode rectifier bridge 2 and the second rectifier bridge 3 work simultaneously, and the output currents of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both three-level stepped DC currents of equal width, and the output voltages of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both six-pulse DC currents of equal width, thereby multiplying the 12 pulses of the series-type 12-pulse rectifier by 3 times to obtain 36 pulses.

[0128] In this embodiment, the non-equal width three-level stepped DC current refers to a current state containing three different current states within one cycle, and the current value output by the rectifier bridge under the same current state is constant, but the duration of each current state is different; the equal width six-pulse DC voltage refers to a voltage output by the rectifier bridge having six pulses within one cycle, and the duration of each pulse is the same.

[0129] In this embodiment, the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit can achieve a 3-fold increase in the number of rectifier pulses without using a phase-shifting voltage transformer with multi-phase output windings and any active switching devices. Compared with the existing 36-pulse rectifier obtained through phase-shifting multiple connections, it has the advantages of simple circuit structure, easy implementation and low cost.

[0130] In this embodiment, the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit of the present invention does not require an inductor to be connected in series on the input side of the 12-pulse rectifier. This avoids the problem of needing to connect a large inductor in series on the AC side of the 12-pulse rectifier when using an auxiliary voltage injection circuit, enabling the rectifier to obtain a higher displacement factor and a stable output voltage, and has better application prospects in medium- and high-voltage high-power applications.

[0131] In this embodiment, the voltage multiplier rectifier 4 is used to multiply the number of voltage pulses it outputs.

[0132] Specific Implementation Method Six: The following is combined with... Figure 6 This embodiment further explains the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit described in Embodiment 5. The voltage multiplier rectifier 4 and the first single-phase auxiliary transformer 5 are used to multiply the number of current levels flowing into the isolation transformer 1.

[0133] Specific Implementation Method Seven: The following is combined with... Figure 6 This embodiment further describes the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit described in Embodiment 5. The voltage multiplier rectifier 4 includes diode D. m1 Diode D m2 Capacitors C3 and C4;

[0134] Diode D m1 After the cathode and one end of capacitor C3 are connected, it serves as the DC output terminal of voltage multiplier rectifier 4;

[0135] Diode D m2 After the anode of the capacitor is connected to one end of the capacitor C4, it serves as the DC input terminal of the voltage multiplier rectifier 4.

[0136] After the other ends of capacitors C3 and C4 are connected, they serve as the first AC input terminal of voltage multiplier rectifier 4.

[0137] Diode D m1 anode and diode D m2 After the cathode is connected, it serves as the second AC input terminal of the voltage multiplier rectifier 4;

[0138] The auxiliary single-phase rectifier bridge 8 includes diode D. n1 Diode D n2 Diode D n3 and diode D n4 ;

[0139] Diode D n1 anode and diode D n2 After the anode is connected, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge 8;

[0140] Diode D n3 cathode and diode D n4 After the cathode is connected, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge 8;

[0141] Diode D n2 Cathode and diode D n4 After the anode is connected, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge 8;

[0142] Diode D n1 Cathode and diode D n3 After the anode is connected, it serves as the second AC input terminal of the auxiliary single-phase rectifier bridge 8.

[0143] In this preferred embodiment, the specific configuration of the auxiliary single-phase rectifier bridge 8 and the voltage multiplier rectifier 4 is given. The structure is simple and easy to implement.

[0144] Specific Implementation Method Seven: The following is combined with... Figures 7 to 9 This embodiment further explains the series-type 36-pulse rectifier with a voltage doubler rectifier pulse multiplier circuit described in Embodiment 7. The voltage doubler rectifier pulse multiplier circuit includes three operating modes, specifically:

[0145] Working Mode I: See Figure 7 , when u s1 >u d2 andu s2 >u s3 At that time, diode D in voltage multiplier rectifier 4 m2 Forward conduction, diode D m1 With reverse cutoff, the first single-phase auxiliary transformer 5, auxiliary single-phase transformer 6, and auxiliary single-phase transformer 7 all operate normally, and the current i flowing into the DC input terminal of the voltage multiplier rectifier 4... s1 The current flows sequentially through diode D m2 The secondary winding CD of the first single-phase auxiliary transformer 5 is split into two paths. One path flows through capacitor C3 and exits from the DC output terminal of the voltage multiplier rectifier 4. The other path flows through C4 and then through diode D. m2The current flows back into the secondary winding CD of the first single-phase auxiliary transformer 5; simultaneously, diode D in the auxiliary single-phase rectifier bridge 8... n1 and diode D n4 Forward conduction, diode D n3 and diode D n4 When in reverse cutoff state, the first diode rectifier bridge 2 and the second diode rectifier bridge 3 together supply power to the load 9;

[0146] Working Mode II: See Figure 8 , when |u s1 | d2 At that time, diode D in voltage multiplier rectifier 4 m1 and D m2 All are reverse cut off and in a non-working state, while no current flows through the two capacitors C3 and C4 in the voltage multiplier rectifier 4; the first single-phase auxiliary transformer 5, the second single-phase auxiliary transformer 6 and the third single-phase auxiliary transformer 7 are all in a non-working state, and all the diodes in the auxiliary single-phase rectifier bridge 8 are in a working state. At this time, the first diode rectifier bridge 2 and the second diode rectifier bridge 3 together supply power to the load 9.

[0147] Working Mode III: See Figure 9 , when -u s1 >u d2 andu s3 >u s2 At that time, diode D in voltage multiplier rectifier 4 m2 Reverse cutoff, diode D m1 Forward conduction; the first single-phase auxiliary transformer 5, the second single-phase auxiliary transformer 6, and the third single-phase auxiliary transformer 7 are all in normal working condition. The current flowing into the secondary winding CD of the first single-phase auxiliary transformer 5 is divided into two parts: one part comes from the current i flowing into the DC input terminal of the voltage multiplier rectifier 4. s1 The current is fed through capacitor C4, and another part comes from the current flowing through capacitor C3; diode D in the auxiliary single-phase rectifier bridge 8. n1 and diode D n4 Both are in reverse cutoff state, diode D n2 and diode D n3 When in forward conduction mode, the first diode rectifier bridge 2 and the second diode rectifier bridge 3 together supply power to the load 9.

[0148] In this preferred embodiment, three operating modes of the voltage multiplier rectifier pulse multiplier circuit in the series-type 36-pulse rectifier with voltage multiplier rectifier pulse multiplier circuit of the second structure are given, and the operating status of each component in each mode is described in detail.

[0149] Principle Analysis:

[0150] This invention is in​ Figure 6 In the circuit structure shown (i.e., the second structure of the present invention, a series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit), a voltage multiplier rectifier pulse multiplier circuit is added to the DC side of a conventional series-type 12-pulse rectifier to modulate and increase the output current and output voltage state number of the first diode rectifier bridge 2 and the second diode rectifier bridge 3. Specifically, the modulation process involves setting the turns ratio of the primary winding to the secondary winding of the first single-phase auxiliary transformer 5, the second single-phase auxiliary transformer 6, and the third single-phase auxiliary transformer 7, so that the voltage connected to the secondary winding of the first single-phase auxiliary transformer 5 is increased. The conduction time of each diode in the multiplier rectifier 4 is one-third of the period of its input voltage. The output current of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 is a periodic three-level DC current. The output voltage of the first diode rectifier bridge 2 and the second diode rectifier bridge 3 are both six-pulse DC voltages with equal width. Based on the AC and DC side voltage and AC and DC side current relationship of the 12-pulse rectifier, the pulse number of the 12-pulse rectifier is increased to 3 times the original, that is, from 12 pulses to 36 pulses. This effectively suppresses the input current harmonics of the rectifier without significantly increasing the complexity of the rectifier.

[0151] 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 series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit, comprising a series-type 12-pulse rectifier and a voltage multiplier rectifier pulse multiplier circuit; the series-type 12-pulse rectifier comprises a phase-shifting transformer (1), a first diode rectifier bridge (2), and a second diode rectifier bridge (3). The 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 output to the first diode rectifier bridge (2) and the second diode rectifier bridge (3), respectively. Its features ； The voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge (2) and the second diode rectifier bridge (3), thereby multiplying the 12 pulses of the series 12-pulse rectifier by 3 times to obtain 36 pulses. The voltage multiplier rectifier pulse multiplier circuit includes an auxiliary single-phase rectifier bridge (4), a multi-winding auxiliary transformer (5), a voltage multiplier rectifier (6), a balancing reactor with a center tap (7), capacitor C1, and capacitor C2. After the positive output terminal of the first diode rectifier bridge (2) is connected to one end of the capacitor C1, it is connected to the positive output terminal of the series 36-pulse rectifier and the positive input terminal of the load (8). After the negative output terminal of the second diode rectifier bridge (3) is connected to one end of the capacitor C2 and the DC input terminal of the voltage multiplier rectifier (6), it is connected to the negative output terminal of the series 36-pulse rectifier and the negative input terminal of the load (8). 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 same-name terminal A of the primary winding AB of the multi-winding auxiliary transformer (5) and the opposite-name terminal D of the secondary winding CD, the first AC input terminal of the auxiliary single-phase rectifier bridge (4) and the DC output terminal of the voltage multiplier rectifier (6) are connected at the same time. The opposite-name terminal B of the primary winding AB of the multi-winding auxiliary transformer (5) is connected to the center tap of the balancing reactor (7) with a center tap. The same-name terminal C of the secondary winding CD of the multi-winding auxiliary transformer (5) is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge (4); The same-name terminal E of the secondary winding EF of the multi-winding auxiliary transformer (5) is connected to the first AC input terminal of the voltage multiplier rectifier (6), and the opposite-name terminal F of the secondary winding EF of the multi-winding auxiliary transformer (5) is connected to the second AC input terminal of the voltage multiplier rectifier (6). The same-name terminal of the center-tapped balancing reactor (7) is connected to the other end of capacitor C1, and the opposite-name terminal of the center-tapped balancing reactor (7) is connected to the other end of capacitor C2. By setting the turns ratio of the primary and secondary windings of the multi-winding auxiliary transformer (5), the conduction time of the diodes in the voltage multiplier rectifier (6) is made to be 1 / 6 of the voltage cycle received between the two AC input terminals of the voltage multiplier rectifier (6), so that the first diode rectifier bridge (2) and the second diode rectifier bridge (3) work simultaneously, and the output currents of the first diode rectifier bridge (2) and the second diode rectifier bridge (3) are both equal-width four-level stepped DC currents, and the output voltages of the first diode rectifier bridge (2) and the second diode rectifier bridge (3) are both equal-width six-pulse DC voltages.

2. The series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit 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 m2 anode and diode D 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); Diode D m1 Cathode and diode D m2 After the cathode is connected, 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). Diode D m3 anode and diode D m4 After the anode is connected, 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 voltage multiplier rectifier (6) includes diode D. n1 Diode D n2 Capacitors C3 and C4; Diode D n1 After the cathode is connected to one end of capacitor C3, it serves as the DC output terminal of the voltage multiplier rectifier (6); Diode D n2 After the anode of the capacitor is connected to one end of the capacitor C4, it serves as the DC input terminal of the voltage multiplier rectifier (6). After the other end of capacitor C3 is connected to the other end of capacitor C4, it serves as the first AC input terminal of the voltage multiplier rectifier (6); Diode D n1 anode and diode D n2 After the cathode is connected, it serves as the second AC input terminal of the voltage multiplier rectifier (6).

3. The series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit according to claim 2, characterized in that, The voltage multiplier rectifier pulse multiplier circuit includes four operating modes, specifically: Working mode I: When |u s1 | d2 , and u s2 When >0, 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 winding EF of the multi-winding auxiliary transformer (5) is in a non-operating state, and the two diodes D in the voltage multiplier rectifier (6) are in a forward conduction state. n1 and D n2 When reverse biased and cut off, no current flows through capacitors C3 and C4. 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 (8).​ u s1 The voltage across the secondary winding EF of the multi-winding auxiliary transformer (5) is u. s2 The voltage across the secondary winding CD of the multi-winding auxiliary transformer (5), u d2 The output voltage of the second diode rectifier bridge (3); Working Mode II: When u s1< u d2 +u s2 , and u s2 When <0, 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 winding EF of the multi-winding auxiliary transformer (5) is in a non-operating state, and the two diodes D in the voltage multiplier rectifier (6) are in a forward conduction state. n1 and D n2 All reverse biased cutoff, no current flows through the capacitor; 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 (8); u s1 The voltage across the secondary winding EF of the multi-winding auxiliary transformer (5) is u. s2 The voltage across the secondary winding CD of the multi-winding auxiliary transformer (5), u d2 The output voltage of the second diode rectifier bridge (3); Working Mode III: When u s2 <0 and -u s1 >u d2 -u s2 At that time, 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; diode D in voltage multiplier rectifier (6) n1 Forward guidance, D n2 When reverse cutoff occurs, the current flowing through capacitors C3 and C4 in the voltage multiplier rectifier (6) enters the E terminal of the secondary winding EF of the multi-winding auxiliary transformer (5). At this time, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) supply power to both ends of the load (8). u s1 The voltage across the secondary winding EF of the multi-winding auxiliary transformer (5) is u. s2 The voltage across the secondary winding CD of the multi-winding auxiliary transformer (5), u d2 The output voltage of the second diode rectifier bridge (3); Working mode IV: When -u s1 >u d2 Andu s2 When >0, diode D in the auxiliary single-phase rectifier bridge (4) m1 diode D m4 Forward conduction, diode D m2 and diode D m3 Reverse bias cutoff; diode D in voltage multiplier rectifier (6) n1 Reverse cutoff, diode D n2 Forward conduction, current i s Through diode D n2 The current flows to capacitors C3 and C4. At this time, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) together supply power to both ends of the load (8). i s For the current flowing through the voltage multiplier rectifier (6), u s1 The voltage across the secondary winding EF of the multi-winding auxiliary transformer (5) is u. s2 The voltage across the secondary winding CD of the multi-winding auxiliary transformer (5), u d2 The output voltage of the second diode rectifier bridge (3) is .

4. A series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit, comprising a series-type 12-pulse rectifier and a voltage multiplier rectifier pulse multiplier circuit; the series-type 12-pulse rectifier comprises a phase-shifting transformer (1), a first diode rectifier bridge (2), and a second diode rectifier bridge (3). The 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 output to the first diode rectifier bridge (2) and the second diode rectifier bridge (3), respectively. Its features ； The voltage multiplier rectifier pulse multiplier circuit is located on the DC side of the series 12-pulse rectifier. It is used to modulate the state number of the output current and output voltage of the first diode rectifier bridge (2) and the second diode rectifier bridge (3), thereby multiplying the 12 pulses of the series 12-pulse rectifier by 3 times to obtain 36 pulses. The voltage multiplier rectifier pulse multiplier circuit includes a voltage multiplier rectifier (4), a first single-phase auxiliary transformer (5), a second single-phase auxiliary transformer (6), a third single-phase auxiliary transformer (7), an auxiliary single-phase rectifier bridge (8), capacitor C1, and capacitor 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 (8) at the same time. The positive output terminal of the auxiliary single-phase rectifier bridge (8) is connected to the positive input terminal of the load (9) as the positive output terminal of the series 36-pulse rectifier. After the negative output terminal of the second diode rectifier bridge (3) is connected to one end of the capacitor C2 and the DC input terminal of the voltage multiplier rectifier (4), it is connected to the negative output terminal of the series 36-pulse rectifier and the negative input terminal of the load (9). The DC output terminal of the voltage multiplier rectifier (4) is simultaneously connected to the same-name terminal A of the primary winding AB of the first single-phase auxiliary transformer (5), the negative output terminal of the first diode rectifier bridge (2), and the positive output terminal of the second diode rectifier bridge (3). The opposite-named terminal B of the primary winding AB of the first single-phase auxiliary transformer (5) is simultaneously connected to the opposite-named terminal F of the primary winding EF of the second single-phase auxiliary transformer (6) and the same-named terminal L of the primary winding LK of the third single-phase auxiliary transformer (7). The same-name terminal C and opposite-name terminal D of the secondary winding CD of the first single-phase auxiliary transformer (5) are connected to the first and second AC input terminals of the voltage multiplier rectifier (4), respectively. The same-name terminal E of the primary winding EF of the second single-phase auxiliary transformer (6) is connected to the other end of the capacitor C1. The same-name terminal H of the secondary winding HG of the second single-phase auxiliary transformer (6) is connected to the first AC input terminal of the auxiliary single-phase rectifier bridge (8). The opposite-name terminal G of the secondary winding HG of the second single-phase auxiliary transformer (6) is connected to the opposite-name terminal I of the secondary winding IJ of the third single-phase auxiliary transformer (7). The opposite-name terminal K of the primary winding LK of the third single-phase auxiliary transformer (7) is connected to the other end of the capacitor C2, and the same-name terminal J of the secondary winding IJ of the third single-phase auxiliary transformer (7) is connected to the second AC input terminal of the auxiliary single-phase rectifier bridge (8). By setting the turns ratio of the primary and secondary windings of the first single-phase auxiliary transformer (5), the second single-phase auxiliary transformer (6) and the third single-phase auxiliary transformer (7), the conduction time of the diodes in the voltage multiplier rectifier (4) is made to be 1 / 3 of the voltage cycle received between the two AC input terminals of the voltage multiplier rectifier (4), so that the first diode rectifier bridge (2) and the second diode rectifier bridge (3) work simultaneously, and the output current of the first diode rectifier bridge (2) and the second diode rectifier bridge (3) are both non-equal width three-level stepped DC currents, and the output voltage of the first diode rectifier bridge (2) and the second diode rectifier bridge (3) are both equal width six-pulse DC voltages.

5. The series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit according to claim 4, characterized in that, The voltage multiplier rectifier (4) includes diode D. m1 Diode D m2 Capacitors C3 and C4; Diode D m1 After the cathode and one end of capacitor C3 are connected, it serves as the DC output terminal of the voltage multiplier rectifier (4); Diode D m2 After the anode of the capacitor is connected to one end of the capacitor C4, it serves as the DC input terminal of the voltage multiplier rectifier (4). After the other end of capacitor C3 and the other end of C4 are connected, they serve as the first AC input terminal of the voltage multiplier rectifier (4); Diode D m1 anode and diode D m2 After the cathode is connected, it serves as the second AC input terminal of the voltage multiplier rectifier (4); The auxiliary single-phase rectifier bridge (8) includes diode D n1 Diode D n2 Diode D n3 and diode D n4 ; Diode D n1 anode and diode D n2 After the anode is connected, it serves as the negative output terminal of the auxiliary single-phase rectifier bridge (8); Diode D n3 cathode and diode D n4 After the cathode is connected, it serves as the positive output terminal of the auxiliary single-phase rectifier bridge (8); Diode D n2 Cathode and diode D n4 After the anode is connected, it serves as the first AC input terminal of the auxiliary single-phase rectifier bridge (8); Diode D n1 Cathode and diode D n3 After the anode is connected, it serves as the second AC input terminal of the auxiliary single-phase rectifier bridge (8).

6. The series-type 36-pulse rectifier with a voltage multiplier rectifier pulse multiplier circuit according to claim 5, characterized in that, The voltage multiplier rectifier pulse multiplier circuit includes three operating modes, specifically: Working Mode I: When u s1 >u d2 Andu s2 >u s3 At that time, the diode D in the voltage multiplier rectifier (4) m2 Forward conduction, diode D m1 With reverse cutoff, the first single-phase auxiliary transformer (5), the second single-phase auxiliary transformer (6), and the third single-phase auxiliary transformer (7) all operate normally, and the current i flowing into the DC input terminal of the voltage multiplier rectifier (4) is... s1 The current flows sequentially through diode D m2 The secondary winding CD of the first single-phase auxiliary transformer (5) is split into two paths. One path flows through capacitor C3 and then out from the DC output terminal of the voltage multiplier rectifier (4). The other path flows through C4 and then through diode D. m2 The current flows back into the secondary winding CD of the first single-phase auxiliary transformer (5); simultaneously, the diode D in the auxiliary single-phase rectifier bridge (8)... n1 and diode D n4 Forward conduction, diode D n3 and diode D n4 When in reverse cutoff state, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) together supply power to the load (9); u s1 The voltage across the secondary winding CD of the first single-phase auxiliary transformer (5); u s2 The voltage across the secondary winding HG of the second single-phase auxiliary transformer (6); u s3 The voltage across the secondary winding IJ of the third single-phase auxiliary transformer (7), u d2 The output voltage of the second diode rectifier bridge (3); Working Mode II: When |u s1 | d2 At that time, the diode D in the voltage multiplier rectifier (4) m1 and D m2 All are reverse cut off and in a non-working state, while no current flows through the two capacitors C3 and C4 in the voltage multiplier rectifier (4); the first single-phase auxiliary transformer (5), the second single-phase auxiliary transformer (6) and the third single-phase auxiliary transformer (7) are all in a non-working state, and all the diodes in the auxiliary single-phase rectifier bridge (8) are in a working state. At this time, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) together supply power to the load (9);​ u s1 The voltage across the secondary winding CD of the first single-phase auxiliary transformer (5); u s2 The voltage across the secondary winding HG of the second single-phase auxiliary transformer (6); u s3 The voltage across the secondary winding IJ of the third single-phase auxiliary transformer (7), u d2 The output voltage of the second diode rectifier bridge (3); Working Mode III: When -u s1 >u d2 Andu s3 >u s2 At that time, diode D in voltage multiplier rectifier (4) m2 Reverse cutoff, diode D m1 Forward conduction; the first single-phase auxiliary transformer (5), the second single-phase auxiliary transformer (6), and the third single-phase auxiliary transformer (7) are all in normal working condition. The current flowing into the secondary winding CD of the first single-phase auxiliary transformer (5) is divided into two parts, one part of which comes from the current i flowing into the DC input terminal of the voltage multiplier rectifier (4). s1 The current is fed through capacitor C4, and another part is fed from the current flowing through capacitor C3; diode D in the auxiliary single-phase rectifier bridge (8) n1 and diode D n4 Both are in reverse cutoff state, diode D n2 and diode D n3 When in the forward conduction state, the first diode rectifier bridge (2) and the second diode rectifier bridge (3) together supply power to the load (9); u s1 The voltage across the secondary winding CD of the first single-phase auxiliary transformer (5); u s2 The voltage across the secondary winding HG of the second single-phase auxiliary transformer (6); u s3 The voltage across the secondary winding IJ of the third single-phase auxiliary transformer (7), u d2 The output voltage of the second diode rectifier bridge (3) is .

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