36-pulse full-wave rectifier based on nine-phase phase-shifting transformers

Abstract

The 36-pulse full-wave rectifier based on nine-phase shift transformer belongs to the technical field of power electronics, and solves the problems of many magnetic devices required by the existing 36-pulse full-wave rectifier and high turn ratio of the secondary side and the primary side of the balancing reactor in the pulse triple multiplication circuit. The isolated nine-phase shift transformer is used for phase-shifting the three-phase alternating current output by the power grid, generating two paths of nine-phase alternating current with a phase difference of 20° and equal amplitude, and sending the two paths of nine-phase alternating current output to the first and second nine-phase half-wave rectifiers for rectification, and the difference voltage between the two direct current voltages formed after rectification is sent to the primary winding of the balancing reactor; the voltage processing circuit rectifies and multiplies the voltage amplitude of the secondary winding of the balancing reactor by 4 times, and the processed voltage obtained is applied to the load, at this time, the voltage output by the first and / or second nine-phase half-wave rectifier is used for power supply of the load. The application is mainly applied to realize rectification.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology. Background Technology

[0002] Compared to multi-pulse full-bridge rectifiers, multi-pulse full-wave rectifiers have lower conduction losses due to having only one diode in the current path. Therefore, they are often used as the rectifier front end in low-voltage, high-current industrial applications such as electrolysis, electroplating, metal smelting, and coil heating. Although the 12-pulse full-wave rectifier has a simple structure, it can only cancel the 5th and 7th harmonics in the input current. The input current still contains a large number of low-order harmonics such as the 11th, 13th, 23rd, and 25th, resulting in a still high total harmonic distortion (THD) that cannot meet the requirements of industrial applications and harmonic standards such as IEEE-519.

[0003] To limit the input current harmonics of the rectifier to the requirements of IEEE-519, increasing the pulse number of the full-wave rectifier to 36 pulses is the most common and effective method. Currently, there are two main methods to form a 36-pulse full-wave rectifier. One method is to further increase the number of phase-shifting transformers to increase the pulse number to 36 pulses, effectively suppressing input current harmonics. However, this approach requires a significant increase in the number of phase-shifting transformers and balancing reactors, as well as a large number of magnetic components. Typically, at least three phase-shifting transformers and at least seven balancing reactors are needed, increasing both the complexity and cost of the rectifier. The second method uses a pulse tripler circuit as an auxiliary circuit to increase the pulse number of a 12-pulse full-wave rectifier, improving it to a 36-pulse full-wave rectifier and reducing the THD of the input current to one-third of its original value. This method has the advantages of simple auxiliary circuit structure, ease of implementation, and low cost. However, the two auxiliary diodes in the pulse tripler circuit are connected in series in the load path, which not only subject them to large current stress but also generate severe conduction losses. Furthermore, the other two auxiliary diodes in the pulse tripler circuit are connected in parallel with the load, resulting in a large number of turns in the secondary and primary windings of the balancing reactor in the pulse tripler circuit. This not only increases its manufacturing difficulty but also subjects them to high voltage stress. Therefore, these problems urgently need to be solved. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of the large number of magnetic devices required in existing 36-pulse full-wave rectifiers and the high turns ratio of the secondary and primary sides of the balancing reactor in the pulse tripler circuit. This invention provides a 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer.

[0005] The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer includes an isolated nine-phase phase-shifting transformer, a first nine-phase half-wave rectifier, a second nine-phase half-wave rectifier, and a voltage quadruple balancing circuit; the voltage quadruple balancing circuit includes a balancing reactor and a voltage processing circuit.

[0006] An isolated nine-phase phase-shifting transformer is used to shift the phase of the three-phase AC current output from the power grid, generating two nine-phase AC currents with a phase difference of 20° and equal amplitude. The two nine-phase AC currents are then sent to the first nine-phase half-wave rectifier and the second nine-phase half-wave rectifier for rectification, respectively. The voltage difference between the two DC voltages formed is then sent to the primary winding of the balancing reactor.

[0007] The voltage processing circuit rectifies and quadruples the voltage amplitude of the output voltage of the secondary winding of the balancing reactor. The resulting processed voltage is applied to the load. At this time, the voltage output by the first nine-phase half-wave rectifier and / or the second nine-phase half-wave rectifier supplies power to the load through the primary winding of the balancing reactor, and the voltage across the load is a 36-pulse voltage.

[0008] Preferably, the voltage processing circuit includes a first auxiliary diode D1, a second auxiliary diode D2, a third auxiliary diode D3, a fourth auxiliary diode D4, and capacitors C1 to C4;

[0009] The positive output terminal of the first nine-phase half-wave rectifier is connected to one end n1 of the primary winding of the balancing reactor.

[0010] The positive output terminal of the second nine-phase half-wave rectifier is connected to the other end n3 of the primary winding of the balancing reactor.

[0011] One end m1 of the secondary winding of the balancing reactor is simultaneously connected to the cathode of the third auxiliary diode D3, the anode of the fourth auxiliary diode D4, one end of capacitor C4, and one end of capacitor C2.

[0012] The other end m2 of the secondary winding of the balancing reactor is connected to one end of capacitor C1 and one end of capacitor C3 at the same time.

[0013] The other end of capacitor C1 is connected to the anode of the first auxiliary diode D1 and the cathode of the second auxiliary diode D2. After the cathode of the first auxiliary diode D1 is connected to the other end of capacitor C2 and the center tap n2 on the primary winding of the balancing reactor, it is connected to the positive output terminal of the 36-pulse full-wave rectifier and the positive terminal of the load.

[0014] The other end of capacitor C3 is connected to the anode of the third auxiliary diode D3 and the cathode of the fourth auxiliary diode D4. The anode of the fourth auxiliary diode D4 is connected to the other end of capacitor C4 and the neutral point of the isolated nine-phase phase-shifting transformer, and then connected to the negative output terminal of the 36-pulse full-wave rectifier and the negative polarity terminal of the load.

[0015] Preferably, N m1m2 :N n1n3 =m=8.1:1; where m is the turns ratio; N m1m2 N is the number of turns in the secondary winding of the balancing reactor. n1n3 The number of turns in the primary winding of the balancing reactor.

[0016] Preferably, both the first nine-phase half-wave rectifier and the second nine-phase half-wave rectifier are implemented using diodes.

[0017] Preferably, the voltage quadruple balancing circuit includes three operating modes, specifically:

[0018] Mode 1: In this mode, due to the voltage division of capacitors C1 and C4, the output voltage u on the secondary side of the balancing reactor... m1m2 >0, and u m1m2 >0.25u d In the voltage processing circuit, the second auxiliary diode D2 and the fourth auxiliary diode D4 are both reverse biased, while the first auxiliary diode D1 and the third auxiliary diode D3 are both conducting. At this time, the current i flowing through the second auxiliary diode D2 and the fourth auxiliary diode D4 is... D2 =i D4 =0, the current i flowing through the first auxiliary diode D1 and the third auxiliary diode D3 is 0. D1 >0, i D3 >0, the first nine-phase half-wave rectifier supplies power to the load; among which...

[0019] u d This is the voltage across the load.

[0020] i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

[0021] Mode 2: In this mode, due to the voltage division of capacitors C2 and C3, the output voltage u on the secondary side of the balancing reactor... m1m2 <0, and |u m1m2 |>0.25u d In the voltage processing circuit, the first auxiliary diode D1 and the third auxiliary diode D3 are both reverse biased, while the second auxiliary diode D2 and the fourth auxiliary diode D4 are both conducting. At this time, the current i flowing through the first auxiliary diode D1 and the second auxiliary diode D3 is... D1=i D3 =0, the current i flowing through the second auxiliary diode D2 and the fourth auxiliary diode D4 is 0. D2 >0, i D4 >0, the second nine-phase half-wave rectifier supplies power to the load; among which...

[0022] u d This is the voltage across the load.

[0023] i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

[0024] Mode 3: In this mode, due to the output voltage u on the secondary side of the balancing reactor... m1m2 <0, and |u m1m2 |<0.25u d In the voltage processing circuit, the first auxiliary diode D1, the second auxiliary diode D2, the third auxiliary diode D3, and the fourth auxiliary diode D4 are all reverse biased, and the current i flowing through the first auxiliary diode D1, the second auxiliary diode D2, the third auxiliary diode D3, and the fourth auxiliary diode D4 is... D1 =i D2 =i D3 =i D4 =0, the first nine-phase half-wave rectifier and the second nine-phase half-wave rectifier supply power to the load; among which,

[0025] u d This is the voltage across the load.

[0026] i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

[0027] Preferably, the primary winding of the isolated nine-phase phase-shifting transformer includes phase a primary winding ra, phase b primary winding rb, and phase c primary winding rc.

[0028] The secondary side of the isolated nine-phase phase-shifting transformer includes a-phase secondary winding units, b-phase secondary winding units, and c-phase secondary winding units; wherein, the a-phase secondary winding unit includes windings ra2, ra6, ra7, r1, r4, rb3, rb8, and rb4; the b-phase secondary winding unit includes windings rb2, ra1, rb6, r2, r5, ra5, rb7, and ra9; and the c-phase secondary winding unit includes windings rb5, rb1, ra3, r3, r6, ra4, ra8, and rb9.

[0029] After the opposite-named terminal of the primary winding ra of phase a is connected to the same-named terminal of the primary winding rb of phase b, it is used to receive the phase a current i output from the power grid. a;

[0030] After the opposite-named terminal of the primary winding rb of phase b is connected to the same-named terminal of the primary winding rc of phase c, it is used to receive the phase b current i output from the power grid. b ;

[0031] After the opposite-named terminal of the c-phase secondary winding unit rc is connected to the same-named terminal of the a-phase primary winding ra, it is used to receive the c-phase current i output from the power grid. c ;

[0032] The same-name terminal of winding r1 is simultaneously connected to the same-name terminal of winding ra1, the opposite-name terminal of winding ra2, and the same-name terminal of winding ra3.

[0033] The same-name terminal of winding r2 is simultaneously connected to the same-name terminal of winding ra4, the opposite-name terminal of winding ra5, and the same-name terminal of winding ra6.

[0034] The same-name terminal of winding r3 is simultaneously connected to the same-name terminal of winding ra7, the opposite-name terminal of winding ra8, and the same-name terminal of winding ra9.

[0035] The opposite-named end of winding r4 is simultaneously connected to the opposite-named end of winding rb7, the same-named end of winding rb8, and the opposite-named end of winding rb9; the opposite-named end of winding r5 is simultaneously connected to the opposite-named end of winding rb1, the same-named end of winding rb2, and the opposite-named end of winding rb3.

[0036] The opposite-named end of winding r6 is simultaneously connected to the opposite-named end of winding rb4, the same-named end of winding rb5, and the opposite-named end of winding rb6.

[0037] The combination of the opposite-named terminal of winding ra1, the same-named terminal of winding ra2, the opposite-named terminal of winding ra3, the opposite-named terminal of winding ra4, the same-named terminal of winding ra5, the opposite-named terminal of winding ra6, the opposite-named terminal of winding ra7, the same-named terminal of winding ra8, and the opposite-named terminal of winding ra9 serves as the output terminal of one nine-phase AC current output from the isolated nine-phase phase-shifting transformer.

[0038] The same-name terminal of winding rb1, the opposite-name terminal of winding rb2, the same-name terminal of winding rb3, the same-name terminal of winding rb4, the opposite-name terminal of winding rb5, the same-name terminal of winding rb6, the same-name terminal of winding rb7, the opposite-name terminal of winding rb8, and the same-name terminal of winding rb9 together form the output terminal of another nine-phase AC current output of the isolation-type nine-phase phase-shifting transformer.

[0039] When the opposite-named end of winding r1 is connected to the opposite-named end of winding r2, the opposite-named end of winding r3, the same-named end of winding r4, the same-named end of winding r5, and the same-named end of winding r6, it serves as the neutral point of the isolated nine-phase phase-shifting transformer.

[0040] The beneficial effects of this invention are:

[0041] This invention mainly employs a 36-pulse full-wave rectifier composed of a 9-phase phase-shifting transformer and a voltage quadruple balancing circuit. The voltage quadruple balancing circuit includes a balancing reactor. The 36-pulse full-wave rectifier based on the 9-phase phase-shifting transformer requires only one phase-shifting transformer. Under the premise of ensuring that the number of turns of the secondary and primary windings of the balancing reactor in the voltage quadruple balancing circuit is small, the number of pulses of the rectifier is increased, effectively suppressing the input current harmonics of the rectifier.

[0042] Compared to existing 36-pulse full-wave rectifiers based on transformer phase shifting, the 36-pulse full-wave rectifier of this invention reduces the number of phase-shifting transformers required from 3 or 6 to 1, and the number of balancing reactors required from 7 or 10 to one. The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer proposed in this invention requires even fewer magnetic components and has a simpler circuit structure. Compared to existing 36-pulse full-wave rectifiers based on pulse tripler balancing reactors, the proposed solution not only avoids the auxiliary diode being directly connected in series in the load path to withstand large current stress and generate severe conduction losses, but also effectively reduces the ratio of the number of turns in the secondary to primary windings of the balancing reactor, making the balancing reactor easier to manufacture and design, while also effectively reducing the voltage stress borne by the auxiliary diode. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer described in this invention; wherein,

[0044] i a i b i c These are the a-phase, b-phase, and c-phase currents input to the isolated nine-phase phase-shifting transformer, respectively; i a1 to i a9 i represents the first nine-phase AC current output from the isolated nine-phase phase-shifting transformer. a1 to i a9 Phase current; i b1 to i b9 i represents the i in the second nine-phase AC current output from the isolated nine-phase phase-shifting transformer. b1 to i b9 Phase current; u d The voltage across load 5, u d1 The output voltage of the first nine-phase half-wave rectifier, u d2 This is the output voltage of the second nine-phase half-wave rectifier;

[0045] Figure 2 This is a schematic diagram of the voltage quadruple balancing circuit in operating mode one.

[0046] Figure 3 This is a schematic diagram of the voltage quadruple balancing circuit in operating mode two.

[0047] Figure 4 This is a schematic diagram of the voltage quadruple balancing circuit in operating mode three.

[0048] Figure 5 This is a graph showing the relationship between the turns ratio of the balancing reactor and the input current THD.

[0049] Figure 6 This is a schematic diagram of the structure of an isolated nine-phase phase-shifting transformer. Detailed Implementation

[0050] 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.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0052] Specific Implementation Method 1: The following is combined with... Figure 1 This embodiment describes a 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer, which includes an isolated nine-phase phase-shifting transformer 1, a first nine-phase half-wave rectifier 2, a second nine-phase half-wave rectifier 3, and a voltage quadruple balancing circuit; the voltage quadruple balancing circuit includes a balancing reactor 4 and a voltage processing circuit.

[0053] The isolated nine-phase phase-shifting transformer 1 is used to shift the phase of the three-phase AC current output from the power grid to generate two nine-phase AC currents with a phase difference of 20° and equal amplitude. The two nine-phase AC currents output are sent to the first nine-phase half-wave rectifier 2 and the second nine-phase half-wave rectifier 3 for rectification, and the voltage difference between the two DC voltages formed is sent to the primary winding of the balancing reactor 4.

[0054] After the voltage processing circuit rectifies and quadruples the voltage amplitude of the output voltage of the secondary winding of the balancing reactor 4, the processed voltage is applied to the load 5. At this time, the voltage output by the first nine-phase half-wave rectifier 2 and / or the second nine-phase half-wave rectifier 3 supplies power to the load 5 through the primary winding of the balancing reactor 4, and the voltage across the load 5 is a 36-pulse voltage.

[0055] In application, the isolated nine-phase phase-shifting transformer 1, the first nine-phase half-wave rectifier 2, and the second nine-phase half-wave rectifier 3 constitute a parallel 18-pulse rectifier. After adding a voltage quadruple balancing circuit, a circulating current is formed between the first nine-phase half-wave rectifier 2, the second nine-phase half-wave rectifier 3, and the voltage quadruple balancing circuit. This circulating current is a positive and negative symmetrical square wave current. The modulation of the square wave circulating current increases the number of states of the current and voltage output by the first nine-phase half-wave rectifier 2 and the second nine-phase half-wave rectifier 3. The parallel 18-pulse rectifier composed of the isolated nine-phase phase-shifting transformer 1, the first nine-phase half-wave rectifier 2, and the second nine-phase half-wave rectifier 3 is transformed from two operating modes into a parallel 36-pulse rectifier with three different operating modes. The three operating modes are as follows: First, the processed voltage output from the voltage processing circuit in the voltage quadruple balancing circuit and the voltage output from the first nine-phase half-wave rectifier 2 supply power to the load 5; Second, the processed voltage output from the voltage processing circuit in the voltage quadruple balancing circuit and the voltage output from the second nine-phase half-wave rectifier 3 supply power to the load 5; Third, the voltage processing circuit in the voltage quadruple balancing circuit does not work, and the voltage output from the first nine-phase half-wave rectifier 2 and the voltage output from the second nine-phase half-wave rectifier 3 jointly supply power to the load 5.

[0056] The square wave circulating current formed on the DC side of the 36-pulse full-wave rectifier increases the number of states of the output current and voltage of the first nine-phase half-wave rectifier 2 and the second nine-phase half-wave rectifier 3, while also increasing the number of current steps and output voltage pulses on the input side of the first nine-phase half-wave rectifier 2 and the second nine-phase half-wave rectifier 3. Furthermore, based on the AC / DC current relationship and the DC voltage relationship of the rectifier, it increases the three-phase AC current i input from the grid to the isolated nine-phase phase-shifting transformer 1. a i b and i c The step number is increased to 36, which increases the output voltage pulse number of the rectifier to 36, effectively suppressing input current harmonics and rectifier output voltage pulsation.

[0057] Figure 1 The paper also provides a specific structure for a voltage processing circuit. This circuit structure is simple and uses only 4 diodes and 4 capacitors. Specifically, the voltage processing circuit includes a first auxiliary diode D1, a second auxiliary diode D2, a third auxiliary diode D3, a fourth auxiliary diode D4, and capacitors C1 to C4.

[0058] The positive output terminal of the first nine-phase half-wave rectifier 2 is connected to one end n1 of the primary winding of the balancing reactor 4.

[0059] The positive output terminal of the second nine-phase half-wave rectifier 3 is connected to the other end n3 of the primary winding of the balancing reactor 4.

[0060] One end m1 of the secondary winding of the balancing reactor 4 is simultaneously connected to the cathode of the third auxiliary diode D3, the anode of the fourth auxiliary diode D4, one end of capacitor C4, and one end of capacitor C2.

[0061] The other end m2 of the secondary winding of the balancing reactor 4 is connected to one end of capacitor C1 and one end of capacitor C3 at the same time;

[0062] The other end of capacitor C1 is connected to the anode of the first auxiliary diode D1 and the cathode of the second auxiliary diode D2. After the cathode of the first auxiliary diode D1 is connected to the other end of capacitor C2 and the center tap n2 on the primary winding of the balancing reactor 4, it is connected to the positive output terminal of the 36-pulse full-wave rectifier and the positive terminal of the load 5.

[0063] The other end of capacitor C3 is connected to the anode of the third auxiliary diode D3 and the cathode of the fourth auxiliary diode D4. The anode of the fourth auxiliary diode D4 is connected to the other end of capacitor C4 and the neutral point of the isolated nine-phase phase-shifting transformer 1, and then connected to the negative output terminal of the 36-pulse full-wave rectifier and the negative polarity terminal of the load 5.

[0064] In practical applications, the auxiliary diodes of the voltage processing circuit in the voltage quadruple balancing circuit form a square wave circulating current on the DC side of the 36-pulse full-wave rectifier according to the magnitude of its input voltage and load voltage.

[0065] Furthermore, see Figure 5 N m1m2 :N n1n3 =m=8.1:1; where m is the turns ratio; N m1m2 N is the number of turns in the four secondary windings of the balancing reactor. n1n3 The number of turns in the primary winding of balancing reactor 4 is given. The ratio of the number of turns in the secondary winding to the primary winding of balancing reactor 4 is small, only 8.1:1. Under the condition of a turns ratio of 8.1:1, the conduction time of the square wave circulating current flowing through the primary winding of balancing reactor 4 in the voltage quadruple balancing circuit is half the period of the input voltage of the voltage quadruple balancing circuit. The three-phase AC current input from the grid to the 36-pulse full-wave rectifier of this invention has 36 steps, and the THD of the three-phase AC current input from the grid to the 36-pulse full-wave rectifier of this invention reaches a minimum value of 5.04%. This effectively reduces the total harmonic distortion (THD) of the input current and effectively reduces the voltage stress on the auxiliary diodes and capacitors in balancing reactor 4.

[0066] In practical applications, both the first nine-phase half-wave rectifier 2 and the second nine-phase half-wave rectifier 3 are implemented using diodes, such as... Figure 1 As shown, each is implemented using nine diodes connected in parallel.

[0067] The voltage quadruple balance circuit includes three operating modes, specifically:

[0068] Mode 1: See Figure 2 In this mode, due to the voltage division of capacitors C1 and C4, the output voltage u on the secondary side of the balancing reactor 4 is... m1m2 >0, and u m1m2 >0.25u d In the voltage processing circuit, the second auxiliary diode D2 and the fourth auxiliary diode D4 are both reverse biased, while the first auxiliary diode D1 and the third auxiliary diode D3 are both conducting. At this time, the current i flowing through the second auxiliary diode D2 and the fourth auxiliary diode D4 is... D2 =i D4 =0, the current i flowing through the first auxiliary diode D1 and the third auxiliary diode D3 is 0. D1 >0, i D3 >0, the first nine-phase half-wave rectifier 2 supplies power to load 5; among which...

[0069] u d This is the voltage across load 5;

[0070] i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

[0071] Mode 2: See Figure 3 In this mode, due to the voltage division of capacitors C2 and C3, the output voltage u on the secondary side of the balancing reactor 4 is... m1m2 <0, and |u m1m2 |>0.25u d In the voltage processing circuit, the first auxiliary diode D1 and the third auxiliary diode D3 are both reverse biased, while the second auxiliary diode D2 and the fourth auxiliary diode D4 are both conducting. At this time, the current i flowing through the first auxiliary diode D1 and the second auxiliary diode D3 is... D1 =i D3 =0, the current i flowing through the second auxiliary diode D2 and the fourth auxiliary diode D4 is 0. D2 >0, i D4 >0, the second nine-phase half-wave rectifier 3 supplies power to load 5; among which...

[0072] u d This is the voltage across load 5;

[0073] i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

[0074] Mode 3: See Figure 4In this mode, due to the output voltage u of the 4th secondary side of the balancing reactor... m1m2 <0, and |u m1m2 |<0.25u d In the voltage processing circuit, the first auxiliary diode D1, the second auxiliary diode D2, the third auxiliary diode D3, and the fourth auxiliary diode D4 are all reverse biased, and the current i flowing through the first auxiliary diode D1, the second auxiliary diode D2, the third auxiliary diode D3, and the fourth auxiliary diode D4 is... D1 =i D2 =i D3 =i D4 =0, the first nine-phase half-wave rectifier 2 and the second nine-phase half-wave rectifier 3 supply power to load 5; where,

[0075] u d This is the voltage across load 5;

[0076] i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

[0077] Figure 6 A schematic diagram of a specific structure of an isolated nine-phase phase-shifting transformer 1 is given. Specifically, the primary side of the isolated nine-phase phase-shifting transformer 1 includes the a-phase primary winding ra, the b-phase primary winding rb, and the c-phase primary winding rc.

[0078] The secondary side of the isolated nine-phase phase-shifting transformer 1 includes an a-phase secondary winding unit, a b-phase secondary winding unit, and a c-phase secondary winding unit; wherein, the a-phase secondary winding unit includes windings ra2, ra6, ra7, r1, r4, rb3, rb8, and rb4; the b-phase secondary winding unit includes windings rb2, ra1, rb6, r2, r5, ra5, rb7, and ra9; and the c-phase secondary winding unit includes windings rb5, rb1, ra3, r3, r6, ra4, ra8, and rb9.

[0079] After the opposite-named terminal of the primary winding ra of phase a is connected to the same-named terminal of the primary winding rb of phase b, it is used to receive the phase a current i output from the power grid. a ;

[0080] After the opposite-named terminal of the primary winding rb of phase b is connected to the same-named terminal of the primary winding rc of phase c, it is used to receive the phase b current i output from the power grid. b ;

[0081] After the opposite-named terminal of the c-phase secondary winding unit rc is connected to the same-named terminal of the a-phase primary winding ra, it is used to receive the c-phase current i output from the power grid. c ;

[0082] The same-name terminal of winding r1 is simultaneously connected to the same-name terminal of winding ra1, the opposite-name terminal of winding ra2, and the same-name terminal of winding ra3.

[0083] The same-name terminal of winding r2 is simultaneously connected to the same-name terminal of winding ra4, the opposite-name terminal of winding ra5, and the same-name terminal of winding ra6.

[0084] The same-name terminal of winding r3 is simultaneously connected to the same-name terminal of winding ra7, the opposite-name terminal of winding ra8, and the same-name terminal of winding ra9.

[0085] The opposite-named end of winding r4 is simultaneously connected to the opposite-named end of winding rb7, the same-named end of winding rb8, and the opposite-named end of winding rb9; the opposite-named end of winding r5 is simultaneously connected to the opposite-named end of winding rb1, the same-named end of winding rb2, and the opposite-named end of winding rb3.

[0086] The opposite-named end of winding r6 is simultaneously connected to the opposite-named end of winding rb4, the same-named end of winding rb5, and the opposite-named end of winding rb6.

[0087] The combination of the opposite-named terminal of winding ra1, the same-named terminal of winding ra2, the opposite-named terminal of winding ra3, the opposite-named terminal of winding ra4, the same-named terminal of winding ra5, the opposite-named terminal of winding ra6, the opposite-named terminal of winding ra7, the same-named terminal of winding ra8, and the opposite-named terminal of winding ra9 serves as the output terminal of one nine-phase AC current output of the isolation-type nine-phase phase-shifting transformer 1.

[0088] The same-name terminal of winding rb1, the opposite-name terminal of winding rb2, the same-name terminal of winding rb3, the same-name terminal of winding rb4, the opposite-name terminal of winding rb5, the same-name terminal of winding rb6, the same-name terminal of winding rb7, the opposite-name terminal of winding rb8, and the same-name terminal of winding rb9 together form the output terminal of another nine-phase AC current output of the isolation-type nine-phase phase-shifting transformer 1.

[0089] When the opposite-named end of winding r1 is connected to the opposite-named end of winding r2, the opposite-named end of winding r3, the same-named end of winding r4, the same-named end of winding r5, and the same-named end of winding r6, it serves as the neutral point of the isolation-type nine-phase phase-shifting transformer 1.

[0090] In practical applications, the neutral point of the isolated nine-phase phase-shifting transformer 1 also serves as the negative output terminal of the first nine-phase half-wave rectifier 2 and the negative output terminal of the second nine-phase half-wave rectifier 3.

[0091] Figure 6In this circuit, the non-named terminals of winding ra1, the same-named terminals of winding ra2, the non-named terminals of winding ra3, the non-named terminals of winding ra4, the same-named terminals of winding ra5, the non-named terminals of winding ra6, the non-named terminals of winding ra7, the same-named terminals of winding ra8, and the non-named terminals of winding ra9 together form the output terminal of one nine-phase AC current output of the isolation-type nine-phase phase-shifting transformer 1, respectively outputting i of the first nine-phase AC current. a1 to i a9 Phase current.

[0092] Figure 6 In this circuit, the terminals of winding rb1 (same name), winding rb2 (different name), winding rb3 (same name), winding rb4 (same name), winding rb5 (different name), winding rb6 (same name), winding rb7 (same name), winding rb8 (different name), and winding rb9 (same name) together form the output terminal of another nine-phase AC current output from the isolation-type nine-phase phase-shifting transformer 1, respectively outputting i from the second nine-phase AC current. b1 to i b9 Phase current.

[0093] Figure 6 The structure of the isolated nine-phase phase-shifting transformer 1 designed in this paper has the functions of completely isolating the primary side from the secondary side and regulating the voltage relationship between the AC and DC sides.

[0094] 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 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer, characterized in that, It includes an isolated nine-phase phase-shifting transformer (1), a first nine-phase half-wave rectifier (2), a second nine-phase half-wave rectifier (3), and a voltage quadruple balancing circuit; the voltage quadruple balancing circuit includes a balancing reactor (4) and a voltage processing circuit; The isolation type nine-phase phase shifting transformer (1) is used to shift the three-phase AC current output from the power grid to generate two nine-phase AC currents with a phase difference of 20° and equal amplitude. The two nine-phase AC currents output are sent to the first nine-phase half-wave rectifier (2) and the second nine-phase half-wave rectifier (3) for rectification. The voltage difference between the two DC voltages formed is sent to the primary winding of the balancing reactor (4). After the voltage processing circuit rectifies and multiplies the voltage amplitude by 4 times the output voltage of the secondary winding of the balancing reactor (4), the processed voltage is applied to the load (5). At this time, the voltage output by the first nine-phase half-wave rectifier (2) and / or the second nine-phase half-wave rectifier (3) supplies power to the load (5) through the primary winding of the balancing reactor (4), and the voltage across the load (5) is a 36-pulse voltage.

2. The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer according to claim 1, characterized in that, The voltage processing circuit includes a first auxiliary diode D1, a second auxiliary diode D2, a third auxiliary diode D3, a fourth auxiliary diode D4, and capacitors C1 to C4; The positive output terminal of the first nine-phase half-wave rectifier (2) is connected to one end n1 of the primary winding of the balancing reactor (4); The positive output terminal of the second nine-phase half-wave rectifier (3) is connected to the other end n3 of the primary winding of the balancing reactor (4); One end m1 of the secondary winding of the balancing reactor (4) is simultaneously connected to the cathode of the third auxiliary diode D3, the anode of the second auxiliary diode D2, one end of capacitor C4, and one end of capacitor C2. The other end m2 of the secondary winding of the balancing reactor (4) is connected to one end of capacitor C1 and one end of capacitor C3 at the same time; The other end of capacitor C1 is connected to the anode of the first auxiliary diode D1 and the cathode of the second auxiliary diode D2 at the same time; the cathode of the first auxiliary diode D1 is connected to the other end of capacitor C2 and the center tap n2 on the primary winding of the balancing reactor (4), and then connected to the positive output terminal of the 36-pulse full-wave rectifier and the positive terminal of the load (5). The other end of capacitor C3 is connected to the anode of the third auxiliary diode D3 and the cathode of the fourth auxiliary diode D4. After the anode of the fourth auxiliary diode D4 is connected to the other end of capacitor C4 and the neutral point of the isolated nine-phase phase-shifting transformer (1), it is connected to the negative output terminal of the 36-pulse full-wave rectifier and the negative polarity terminal of the load (5).

3. The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer according to claim 2, characterized in that, N m1m2 :N n1n3 =m=8.1:1; where m is the turns ratio; N m1m2 The number of turns of the secondary winding of the balancing reactor (4); N n1n3 The number of turns of the primary winding of the balancing reactor (4).

4. The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer according to claim 1, characterized in that, Both the first nine-phase half-wave rectifier (2) and the second nine-phase half-wave rectifier (3) are implemented using diodes.

5. The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer according to claim 1, characterized in that, The voltage quadruple balance circuit includes three operating modes, specifically: Mode 1: In this mode, due to the voltage division of capacitors C1 and C4, the output voltage u on the secondary side of the balancing reactor (4) is... m1m2 >0, and u m1m2 >0.25u d In the voltage processing circuit, the second auxiliary diode D2 and the fourth auxiliary diode D4 are both reverse biased, while the first auxiliary diode D1 and the third auxiliary diode D3 are both conducting. At this time, the current i flowing through the second auxiliary diode D2 and the fourth auxiliary diode D4 is... D2 =i D4 =0, the current i flowing through the first auxiliary diode D1 and the third auxiliary diode D3 is 0. D1 >0, i D3 >0, the first nine-phase half-wave rectifier (2) supplies power to the load (5); among which, u d The voltage across the load (5); i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively. Mode 2: In this mode, due to the voltage division of capacitors C2 and C3, the output voltage u on the secondary side of the balancing reactor (4) is... m1m2 <0, and |u m1m2 |>0.25u d In the voltage processing circuit, the first auxiliary diode D1 and the third auxiliary diode D3 are both reverse biased, while the second auxiliary diode D2 and the fourth auxiliary diode D4 are both conducting. At this time, the current i flowing through the first auxiliary diode D1 and the second auxiliary diode D3 is... D1 =i D3 =0, the current i flowing through the second auxiliary diode D2 and the fourth auxiliary diode D4 is 0. D2 >0, i D4 >0, the second nine-phase half-wave rectifier (3) supplies power to the load (5); among which, u d The voltage across the load (5); i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively. Mode 3: In this mode, due to the output voltage u on the secondary side of the balancing reactor (4) m1m2 <0, and |u m1m2 |<0.25u d In the voltage processing circuit, the first auxiliary diode D1, the second auxiliary diode D2, the third auxiliary diode D3, and the fourth auxiliary diode D4 are all reverse biased, and the current i flowing through the first auxiliary diode D1, the second auxiliary diode D2, the third auxiliary diode D3, and the fourth auxiliary diode D4 is... D1 =i D2 =i D3 =i D4 =0, the first nine-phase half-wave rectifier (2) and the second nine-phase half-wave rectifier (3) supply power to the load (5); among which, u d The voltage across the load (5); i D1 to i D4 These represent the currents flowing through the first auxiliary diode D1 to the fourth auxiliary diode D4, respectively.

6. The 36-pulse full-wave rectifier based on a nine-phase phase-shifting transformer according to claim 1, characterized in that, The primary winding of the isolated nine-phase phase-shifting transformer (1) includes the a-phase primary winding ra, the b-phase primary winding rb, and the c-phase primary winding rc. The secondary side of the isolated nine-phase phase-shifting transformer (1) includes a-phase secondary winding unit, b-phase secondary winding unit and c-phase secondary winding unit; wherein, the a-phase secondary winding unit includes windings ra2, ra6, ra7, r1, r4, rb3, rb8 and rb4; the b-phase secondary winding unit includes windings rb2, ra1, rb6, r2, r5, ra5, rb7 and ra9; the c-phase secondary winding unit includes windings rb5, rb1, ra3, r3, r6, ra4, ra8 and rb9; After the opposite-named terminal of the primary winding ra of phase a is connected to the same-named terminal of the primary winding rb of phase b, it is used to receive the phase a current i output from the power grid. a ; After the opposite-named terminal of the primary winding rb of phase b is connected to the same-named terminal of the primary winding rc of phase c, it is used to receive the phase b current i output from the power grid. b ; After the opposite-named terminal of the c-phase secondary winding unit rc is connected to the same-named terminal of the a-phase primary winding ra, it is used to receive the c-phase current i output from the power grid. c ; The same-name terminal of winding r1 is simultaneously connected to the same-name terminal of winding ra1, the opposite-name terminal of winding ra2, and the same-name terminal of winding ra3. The same-name terminal of winding r2 is simultaneously connected to the same-name terminal of winding ra4, the opposite-name terminal of winding ra5, and the same-name terminal of winding ra6. The same-name terminal of winding r3 is simultaneously connected to the same-name terminal of winding ra7, the opposite-name terminal of winding ra8, and the same-name terminal of winding ra9. The opposite-named end of winding r4 is simultaneously connected to the opposite-named end of winding rb7, the same-named end of winding rb8, and the opposite-named end of winding rb9; the opposite-named end of winding r5 is simultaneously connected to the opposite-named end of winding rb1, the same-named end of winding rb2, and the opposite-named end of winding rb3. The opposite-named end of winding r6 is simultaneously connected to the opposite-named end of winding rb4, the same-named end of winding rb5, and the opposite-named end of winding rb6. The combination of the opposite-named terminal of winding ra1, the same-named terminal of winding ra2, the opposite-named terminal of winding ra3, the opposite-named terminal of winding ra4, the same-named terminal of winding ra5, the opposite-named terminal of winding ra6, the opposite-named terminal of winding ra7, the same-named terminal of winding ra8, and the opposite-named terminal of winding ra9 serves as the output terminal of one nine-phase AC current output by the isolated nine-phase phase-shifting transformer (1). The same-name terminal of winding rb1, the opposite-name terminal of winding rb2, the same-name terminal of winding rb3, the same-name terminal of winding rb4, the opposite-name terminal of winding rb5, the same-name terminal of winding rb6, the same-name terminal of winding rb7, the opposite-name terminal of winding rb8, and the same-name terminal of winding rb9 form a whole, which serves as the output terminal of another nine-phase AC current output by the isolation-type nine-phase phase-shifting transformer (1). After the opposite-named end of winding r1 is connected to the opposite-named end of winding r2, the opposite-named end of winding r3, the same-named end of winding r4, the same-named end of winding r5, and the same-named end of winding r6, it serves as the neutral point of the isolated nine-phase phase-shifting transformer (1).

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