Asymmetric parallel three-phase hydrogen production power supply

Abstract

According to the asymmetric parallel type three-phase hydrogen production power supply provided by the invention, the fault tolerance of the circuit is enhanced by adding the parallel circuit and the parallel design, and the asymmetric parallel type three-phase hydrogen production power supply is more suitable for a large-current hydrogen production scene, so that the cost-effectiveness and high-power requirements in electrolytic hydrogen production can be efficiently met, and the asymmetric parallel type three-phase hydrogen production power supply has the characteristics of low voltage and high current. Meanwhile, an asymmetric circuit is arranged, the turn ratios of primary and secondary windings of the first group of passive pulse wave multiplication circuit (5) and the second group of passive pulse wave multiplication circuit (6) are different, different multiplication effects are achieved, the two small-capacity injection circuits can achieve phase deviation through different turn ratios, and therefore a phase-shifting transformer does not need to be used; and the circuit design process becomes simpler. According to the invention, only two asymmetric circuits without phase-shifting transformers need to be connected in parallel, and current harmonics generated by the harmonic injection circuit are injected into the direct current side of the rectifier, so that the input current is closer to sine waves, the ripple rate of the output current of the rectifier reaches 2.5%, and the electric energy quality is obviously improved.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen production, and in particular to an asymmetric parallel three-phase hydrogen production power supply. Background Art

[0002] As a zero-carbon green renewable energy, hydrogen energy can achieve zero emissions and zero pollution from development to utilization, and has great potential in reducing greenhouse gas emissions, promoting sustainable development, and enhancing energy security. Compared with traditional hydrogen production methods, electrolysis has attracted widespread attention due to its environmental friendliness, diverse energy sources, high purity, and fast reaction speed.

[0003] The high energy consumption associated with large-scale hydrogen production and the additional losses caused by DC ripple in the electrolytic cell (EC) will reduce the efficiency of hydrogen production. Various power converters have been adapted for use in ECs, which are divided into high-frequency, medium-frequency and line-frequency methods. In the high-frequency method, although the DC ripple can be effectively reduced, its high cost limits its practical application. While reducing costs, the medium-frequency converter faces high total harmonic distortion (THD), which does not meet harmonic standards such as IEEE-519 and IEC-610003-2, affecting its ability to be connected to the grid in microgrids. The 12-pulse rectifier of the line-frequency method is widely used in high-power applications due to its excellent overload capacity and low electromagnetic interference, but it also has the THD problem, which limits its possibility of direct grid connection. In addition, increasing the number of phase-shifting transformers and improving the winding method is a way to solve THD, but its complexity and cost are still a major obstacle.

[0004] In view of this, the existing DC side passive current modulation technology uses advanced tapped reactors to generate square wave circulating current on the DC side, which doubles the number of rectifier pulses, suppresses grid side harmonics, and reduces output current ripple; based on the passive injection current circuit of the dual auxiliary transformer, a specific square wave current is generated to modulate the input current from 12 pulses to 24 pulses. Two large capacitors are required on the DC side of the rectifier to provide a neutral point. These capacitors are subject to high current stress, increase losses and reduce the service life of the rectifier. However, compared with the new 24-pulse rectifier, the conventional tap converter (CTC) and the improved tap converter (ITC) are combined. This method has a simple structure and is easy to implement, but the harmonic suppression capability of the CTC is limited. Its auxiliary diode is connected in series on the load path. Since the hydrogen production rate is proportional to the average value of the DC current, it needs to withstand a large current. On the other hand, an auxiliary single-phase full-wave rectifier (ASFR) is used and installed in parallel on the DC side, but this configuration requires two double-star transformers to provide a 30° phase shift on the secondary side.

[0005] Therefore, in order to effectively solve the cost-effectiveness and high power requirements in electrolytic hydrogen production, it is particularly necessary to comprehensively analyze the working specifications, input and output currents, capacity, etc. of magnetic devices and adopt a practical and effective electrolytic hydrogen production solution. Summary of the invention

[0006] In view of the problems in the prior art, an embodiment of the present invention provides an asymmetric parallel three-phase hydrogen production power supply to solve the problems of low cost-effectiveness, high power and the like in the prior art.

[0007] Illustratively, the embodiments of the present invention provide the following technical solutions:

[0008] The embodiment of the present invention provides an asymmetric parallel three-phase hydrogen production power supply, comprising:

[0009] A first group of transformer and rectifier units, a second group of transformer and rectifier units, a first group of passive pulse multiplier circuits (5), a second group of passive pulse multiplier circuits (6) and a balancing reactor (7); wherein the first group of transformer and rectifier units comprises a first group of transformers (1) and a first group of pulse rectifiers (3), and the second group of transformer and rectifier units comprises a second group of transformers (2) and a second group of pulse rectifiers (4);

[0010] The first transformer group (1) and the second transformer group (2) have the same structure. The first transformer group (1) is used to supply three-phase power to the first pulse rectifier group (3), and the second transformer group (2) is used to supply three-phase power to the second pulse rectifier group (4). The current amplitudes of the upper and lower three-phase alternating currents respectively supplied to the first pulse rectifier group (3) and the second pulse rectifier group (4) are the same, and the two transformer groups are non-phase shifting transformers.

[0011] The output end of the first group of pulse rectifiers (3) is connected to the input end of the first group of passive pulse multiplication circuits (5), the output end of the second group of pulse rectifiers (4) is connected to the input end of the second group of passive pulse multiplication circuits (6), and the output ends of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are respectively connected to the two sides of the balancing reactor (7);

[0012] The center point of the balancing reactor (7), the first group of transformer-rectifier units and the second transformer-rectifier unit are respectively connected to the positive and negative sides of an electrolyzer for producing hydrogen by electrolysis;

[0013] The turns ratio of the primary and secondary windings of the first group of passive pulse multiplication circuits (5) and the turns ratio of the primary and secondary windings of the second group of passive pulse multiplication circuits (6) are different, and have different multiplication effects, so that the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are connected in parallel to the balancing reactor (7) to have a phase shift effect.

[0014] In a possible implementation manner, the ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) is a first preset value;

[0015] Wherein, the first preset value is the ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) when the root mean square output voltages of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are equal.

[0016] In a possible implementation, the first group of passive pulse multiplication circuits (5) comprises a balanced inductor with a secondary center tap, a first diode D1 and a second diode D2; the second group of passive pulse multiplication circuits (6) comprises a balanced inductor with a secondary center tap, a third diode D3 and a fourth diode D4;

[0017] The same-name end of the secondary winding of the balancing reactor with a secondary center tap in the first group of passive pulse multiplication circuits (5) is connected to the anode of the first diode D1, and the opposite-name end of the lower secondary winding is connected to the anode of the second diode D2. The cathodes of D1 and D2 are connected to form the output end of the first group of passive pulse multiplication circuits (5) and are connected to the center point of the primary winding;

[0018] The same-name end of the upper secondary winding of the balancing reactor with the primary-secondary center tap in the second group of passive pulse multiplication circuits (6) is connected to the anode of the third diode D3, and the opposite-name end of the lower secondary winding is connected to the anode of the fourth diode D4. The cathodes of D3 and D4 are connected to form the output end of the second group of passive pulse multiplication circuits (6) and are connected to the center point of the primary winding;

[0019] The ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing inductor with a secondary center tap in the first group of passive pulse multiplication circuits (5) is different from the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing inductor with a secondary center tap in the second group of passive pulse multiplication circuits (6).

[0020] In a possible implementation, the ratio of the number of turns of the secondary winding of the balancing reactor with a secondary center tap to the number of turns of the primary winding in the first group of passive pulse multiplication circuits (5) is within a first preset ratio range, and the ratio of the number of turns of the secondary winding of the balancing reactor with a secondary center tap to the number of turns of the primary winding in the second group of passive pulse multiplication circuits (6) is within a second preset ratio range;

[0021] Among them, the first preset ratio range and the second preset ratio range are different, the upper limit value of the first preset ratio range is smaller than the lower limit value of the second preset ratio range, or the upper limit value of the second preset ratio range is smaller than the lower limit value of the first preset ratio range.

[0022] In a possible implementation, the first group of transformer-rectifier units and the second group of transformer-rectifier units are connected to a side of the electrolytic cell that is a neutral point of the first group of transformers (1) and the second group of transformers (2);

[0023] The center point of the balancing reactor (7) is connected to the positive side of the electrolytic cell, and the neutral points of the first group of transformers (1) and the second group of transformers (2) are connected to the negative side of the electrolytic cell.

[0024] In a possible implementation, the first group of transformers (1) are double reverse star transformers, and the second group of transformers (2) are double reverse star transformers;

[0025] The first group of pulse rectifiers (3) is a multi-pulse diode bridge rectifier, and the second group of pulse rectifiers (4) is a multi-pulse diode bridge rectifier. The two groups of multi-pulse diode bridge rectifiers have the same structure.

[0026] The two groups of stars on the secondary side of each double reverse star transformer are respectively connected to the upper and lower half waves of a rectifier connected thereto.

[0027] In a possible implementation, the first group of transformer-rectifier units and the second group of transformer-rectifier units are connected to the side of the electrolytic cell which is the output end of the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4);

[0028] The center point of the balancing reactor (7) is connected to the positive side of the electrolytic cell, and the output ends of the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are connected to the negative side of the electrolytic cell.

[0029] In a possible implementation, the power supply further comprises a first group of zero-sequence current suppressors (8) arranged between the first group of pulse rectifiers (3) and the first group of passive pulse multiplication circuits (5), and a second group of zero-sequence current suppressors (9) arranged between the second group of pulse rectifiers (4) and the second group of passive pulse multiplication circuits (6), wherein one pulse rectifier is connected to one zero-sequence current suppressor.

[0030] The positive output end of the first group of zero-sequence current suppressors (8) is connected to the input end of the first group of passive pulse multiplication circuits (5), and the positive output end of the second group of zero-sequence current suppressors (9) is connected to the input end of the second group of passive pulse multiplication circuits (6);

[0031] The center point of the balancing reactor (7) and the negative output ends of the first group of zero-sequence current suppressors (8) and the second group of zero-sequence current suppressors (9) are respectively connected to the positive and negative sides of an electrolytic cell for producing hydrogen by electrolysis.

[0032] In a possible implementation, the first group of transformers (1) is a first group of autotransformers, and the second group of transformers (2) is a second group of autotransformers;

[0033] The first group of pulse rectifiers (3) includes two multi-pulse diode bridge rectifiers connected in parallel, and the second group of pulse rectifiers (4) includes two multi-pulse diode bridge rectifiers connected in parallel, and the multi-pulse diode bridge rectifiers have the same structure;

[0034] The first group of autotransformers is used to generate two five-phase voltages respectively and supply them to two multi-pulse diode bridge rectifiers in the first group of pulse rectifiers (3); the second group of autotransformers is used to generate two five-phase voltages respectively and supply them to two multi-pulse diode bridge rectifiers in the second group of pulse rectifiers (4).

[0035] In a possible implementation, a ratio m1 of the number of turns up1 of the secondary winding of the balancing reactor to the number of turns ux1 of the primary winding of the balancing reactor of the first group of passive pulse multiplication circuits (5) is 1.8-2.2; and a ratio m2 of the number of turns up3 of the secondary winding of the balancing reactor to the number of turns ux2 of the primary winding of the balancing reactor of the second group of passive pulse multiplication circuits (6) is 6-6.5.

[0036] The asymmetric parallel three-phase hydrogen production power supply provided in the embodiment of the present invention enhances the circuit fault tolerance by adding a parallel circuit, and is more suitable for large current hydrogen production scenarios. The asymmetric parallel high-power three-phase hydrogen production power supply of the embodiment of the present invention has a parallel circuit, so that it can efficiently cope with the cost-effectiveness and high power requirements in electrolytic hydrogen production, and has the characteristics of low voltage and high current. At the same time, an asymmetric circuit is set, that is, the turns ratio of the primary and secondary windings of the first group of passive pulse multiplication circuits (5) and the turns ratio of the primary and secondary windings of the second group of passive pulse multiplication circuits (6) are set to different values. In this way, the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) have different multiplication effects, thereby achieving a phase shift effect, without the need to use a phase shift transformer, and the circuit design process becomes simpler. The embodiment of the present invention changes the turns ratio of two balancing reactors with secondary windings so that the two achieve different pulse multiplication effects. After voltage division by the balancing reactor, the grid-side current finally appears as a pulse that is closer to a sine wave, and the output current ripple rate of the rectifier is significantly reduced. The novel asymmetric parallel pulse rectifier is suitable for a water electrolysis hydrogen production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A topological structure diagram of an exemplary novel asymmetric parallel three-phase hydrogen production power supply provided in one embodiment of the present invention;

[0039] Figure 2 A topological structure diagram of another exemplary novel asymmetric parallel three-phase hydrogen production power supply provided in one embodiment of the present invention;

[0040] Figure 3 A winding structure diagram of a first group of transformers provided in one embodiment of the present invention;

[0041] Figure 4 A winding structure diagram of a second group of transformers provided in one embodiment of the present invention;

[0042] Figure 5 (a) is a waveform generation principle diagram when two passive pulse multiplication circuits provided in one embodiment of the present invention adopt a symmetrical structure, and (b) is a waveform generation principle diagram when two passive pulse multiplication circuits provided in one embodiment of the present invention adopt an asymmetrical structure;

[0043] Figure 6 A modal diagram of a first group of passive pulse multiplication circuits in a working mode according to an embodiment of the present invention;

[0044] Figure 7 A modal diagram of a first group of passive pulse multiplication circuits provided in an embodiment of the present invention in working mode 2; and

[0045] Figure 8 This is a modal diagram of a first set of passive pulse multiplication circuits provided in working mode three according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Hydrogen production by electrolysis has attracted widespread attention due to its environmental friendliness, diverse energy sources, high purity of hydrogen production, and fast reaction speed. The high energy consumption associated with large-scale hydrogen production and the additional losses caused by DC ripple in ECs will reduce the efficiency of hydrogen production. Various power converters have been adapted for use in ECs, which are divided into high-frequency, medium-frequency, and line-frequency methods. The above-mentioned high-frequency, medium-frequency, and line-frequency methods all have their own disadvantages, such as high cost, high THD, and other problems. Other existing methods also have problems such as high cost, high THD, the need to provide phase shift, increased losses, and the need to withstand large currents.

[0048] In order to solve the problems of low cost-effectiveness, high power, high THD, etc. in the existing large-scale hydrogen production, the present invention increases the circuit fault tolerance by adding a parallel circuit, and the parallel design is more suitable for large current hydrogen production scenarios, so that the cost-effectiveness and high power requirements in electrolytic hydrogen production can be efficiently dealt with, and it has the characteristics of low voltage and high current. At the same time, an asymmetric circuit is set, and the turns ratio of the primary and secondary windings of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are different, and have different multiplication effects, thereby achieving a phase shift effect, without the need to use a phase shift transformer, and the circuit design process becomes simpler.

[0049] First, refer to Figure 1 , which shows a topological structure diagram of an asymmetric parallel three-phase hydrogen production power supply provided by the first embodiment of the present invention.

[0050] like Figure 1 As shown, the asymmetric parallel three-phase hydrogen production power supply 100 provided in the first embodiment of the present invention comprises: a first set of double reverse star transformers (1), a second set of double reverse star transformers (2), a first set of pulse rectifiers (3), a second set of pulse rectifiers (4), a first set of passive pulse multiplication circuits (5), a second set of passive pulse multiplication circuits (6) and a balancing reactor (7).

[0051] The first set of double reverse star transformers (1) and the second set of double reverse star transformers (2) are connected in parallel, the first set of pulse rectifiers (3) and the second set of pulse rectifiers (4) are connected in parallel, and the first set of passive pulse multiplication circuits (5) and the second set of passive pulse multiplication circuits (6) are connected in parallel. That is, the first set of double reverse star transformers (1), the first set of pulse rectifiers (3), the first set of passive pulse multiplication circuits (5) and the balancing reactor (7) form a first set of circuits; the second set of double reverse star transformers (2), the second set of pulse rectifiers (4), the second set of passive pulse multiplication circuits (6) and the balancing reactor (7) form a second set of circuits. The first set of circuits and the second set of circuits constitute a parallel circuit.

[0052] In one example, the above devices are connected as follows:

[0053] The first set of double reverse star transformers (1) is used to supply three-phase power supply to the first set of pulse rectifiers (3), and the second set of double reverse star transformers (2) is used to supply three-phase power supply to the second set of pulse rectifiers (4). The output end of the first set of pulse rectifiers (3) is connected to the first set of passive pulse multiplication circuits (5), and the output end of the second set of pulse rectifiers (4) is connected to the second set of passive pulse multiplication circuits (6). The output ends of the first set of passive pulse multiplication circuits (5) and the second set of passive pulse multiplication circuits (6) are respectively connected to the two sides of the balancing reactor (7).

[0054] The first set of double reverse star transformers (1) and the first set of pulse rectifiers (3) can be referred to as the first set of transformer-rectifier units; the second set of double reverse star transformers (2) and the second set of pulse rectifiers (4) can be referred to as the second set of transformer-rectifier units. The center point of the balancing reactor (7), and the first set of transformer-rectifier units and the second set of transformer-rectifier units are respectively connected to the positive and negative sides of the electrolyzer for producing hydrogen by electrolysis. In this embodiment, the first set of transformer-rectifier units and the second set of transformer-rectifier units are connected to the neutral point of the first set of double reverse star transformers (1) and the second set of double reverse star transformers (2) on one side of the electrolyzer, that is, the center point of the balancing reactor (7) is connected to the positive side of the electrolyzer, and the neutral point of the first set of double reverse star transformers (1) and the second set of double reverse star transformers (2) is connected to the negative side of the electrolyzer.

[0055] The present invention increases the circuit fault tolerance by adding parallel circuits and the parallel design is more suitable for large current hydrogen production scenarios, so that the cost-effectiveness and high power requirements in electrolytic hydrogen production can be efficiently addressed, and it has the characteristics of low voltage and high current.

[0056] In one example, the turns ratio of the primary and secondary windings of the first passive pulse multiplication circuit (5) and the turns ratio of the primary and secondary windings of the second passive pulse multiplication circuit (6) are different, and have different multiplication effects, so that the first passive pulse multiplication circuit (5) and the second passive pulse multiplication circuit (6) are connected in parallel to the balancing reactor (7) to have a phase shifting effect. In one example, the two sets of transformers are non-phase shifting transformers. At the same time, an asymmetric circuit is set, and the turns ratio of the primary and secondary windings of the first passive pulse multiplication circuit (5) and the second passive pulse multiplication circuit (6) are different, and have different multiplication effects, so as to achieve a phase shifting effect without using a phase shifting transformer, that is, without the need for the two sets of transformers to be phase shifting transformers, and the circuit design process becomes simpler. Figure 5 (a) and (b) are respectively a waveform generation principle diagram when two passive pulse multiplication circuits provided in one embodiment of the present invention adopt a symmetrical structure, and a waveform generation principle diagram when two passive pulse multiplication circuits provided in one embodiment of the present invention adopt an asymmetrical structure.

[0057] exist Figure 1 , two groups of pulse rectifiers (3) and (4) are shown. The first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are respectively arranged in two parallel circuits, that is, in this embodiment, each circuit in the parallel circuit includes only one group of pulse rectifiers (3). Of course, those skilled in the art will know that each circuit in the parallel circuit includes multiple groups of pulse rectifiers. For example, Figure 2 Each of the parallel circuits shown in FIG. 1 includes two groups of pulse wave rectifiers. In one example, the number of parallel circuits is not limited to Figure 1The two circuits shown in the figure may also be multiple circuits forming a parallel circuit. In one example, the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) have the same structure, and the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) include six diodes.

[0058] In this embodiment, the transformers (1) and (2) in each group are double reverse star transformers. Of course, those skilled in the art will appreciate that the first group of transformers (1) and the second group of transformers (2) may also be other suitable transformer types. Figure 3 A winding structure diagram of a first group of transformers provided in one embodiment of the present invention; Figure 4 A winding structure diagram of a second group of transformers provided in one embodiment of the present invention.

[0059] In one example, the first set of double reverse star transformers (1) and the second set of double reverse star transformers (2) have the same structure. The current amplitudes of the upper and lower sets of three-phase alternating currents supplied by the first set of double reverse star transformers (1) and the second set of double reverse star transformers (2) to the first set of pulse rectifiers (3) and the second set of pulse rectifiers (4) are the same.

[0060] Due to the asymmetric design of the turns ratio of the multiplication circuit winding, there is a deviation in the root mean square voltage at both ends of the balancing reactor, which may lead to a DC magnetization problem. In order to make the output root mean square voltages of the two pulse multiplication circuits equal, the ratio of the turns ratio k2 of the second set of double reverse star transformers (2) to the turns ratio k1 of the first set of double reverse star transformers (1) is set to a first preset value. The ratio of the turns ratio of the first set of double reverse star transformers (1) to the turns ratio of the second set of double reverse star transformers (2) is the first preset value; wherein the first preset value is the ratio of the turns ratio of the first set of double reverse star transformers (1) to the turns ratio of the second set of double reverse star transformers (2) when the output root mean square voltages of the first set of passive pulse multiplication circuits (5) and the second set of passive pulse multiplication circuits (6) are equal. In this way, by setting the ratio of the turns ratio of the first set of double reverse star transformers (1) and the turns ratio of the second set of double reverse star transformers (2) to a specific value, the root mean square output voltages of the two pulse multiplication circuits are equal, thereby reducing or eliminating the DC magnetization problem caused by the asymmetric design of the turns ratio of the multiplication circuit windings.

[0061] The following is another exemplary embodiment of the present application, referring to Figure 2 , which shows a topological structure diagram of another exemplary asymmetric parallel three-phase hydrogen production power supply provided by the first embodiment of the present invention.

[0062] The asymmetric parallel three-phase hydrogen production power supply 200 provided in this embodiment comprises: a first group of autotransformers (1), a second group of autotransformers (2), a first group of pulse rectifiers (3), a second group of pulse rectifiers (4), a first group of passive pulse multiplication circuits (5), a second group of passive pulse multiplication circuits (6) and a balancing reactor (7).

[0063] The first group of autotransformers (1) and the second group of autotransformers (2) are connected in parallel, the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are connected in parallel, and the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are connected in parallel. That is, the first group of autotransformers (1), the first group of pulse rectifiers (3), the first group of passive pulse multiplication circuits (5) and the balancing reactor (7) form a first group of circuits; the second group of autotransformers (2), the second group of pulse rectifiers (4), the second group of passive pulse multiplication circuits (6) and the balancing reactor (7) form a second group of circuits. The first group of circuits and the second group of circuits constitute a parallel circuit.

[0064] In one example, the above devices are connected as follows:

[0065] The first group of autotransformers (1) is used to supply three-phase power supply to the first group of pulse rectifiers (3), and the second group of autotransformers (2) is used to supply three-phase power supply to the second group of pulse rectifiers (4). The output end of the first group of pulse rectifiers (3) is connected to the input end of the first group of passive pulse multiplication circuits (5), and the output end of the second group of pulse rectifiers (4) is connected to the input end of the second group of passive pulse multiplication circuits (6). The output ends of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are respectively connected to the two sides of the balancing reactor (7).

[0066] The center point of the balancing reactor (7) and the output ends of the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are respectively connected to the positive and negative sides of the electrolytic cell for electrolytic hydrogen production. In this embodiment, the difference from the first embodiment is that the output ends of the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are connected to one side of the electrolytic cell instead of the neutral points of the first group of transformers (1) and the second group of transformers (2).

[0067] In an example of this embodiment, the power supply further comprises a first group of zero-sequence current suppressors (8) arranged between the first group of pulse rectifiers (3) and the first group of passive pulse multiplication circuits (5), and a second group of zero-sequence current suppressors (9) arranged between the second group of pulse rectifiers (4) and the second group of passive pulse multiplication circuits (6). One pulse rectifier is connected to one zero-sequence current suppressor. The positive output end of the first group of zero-sequence current suppressors (8) is connected to the input end of the first group of passive pulse multiplication circuits (5), and the positive output end of the second group of zero-sequence current suppressors (9) is connected to the input end of the second group of passive pulse multiplication circuits (6).

[0068] In this embodiment, what is different from the above-mentioned embodiment is that the center point of the balancing reactor (7), and the negative output ends of the first group of zero-sequence current suppressors (8) and the second group of zero-sequence current suppressors (9) are respectively connected to the positive and negative sides of the electrolytic cell for producing hydrogen by electrolysis.

[0069] See also Figure 2 As shown, the number of zero-sequence current suppressors in the first group of zero-sequence current suppressors (8) is 2, and the number of zero-sequence current suppressors in the second group of zero-sequence current suppressors (9) is 2. The number of zero-sequence current suppressors in each group of zero-sequence current suppressors may be other values.

[0070] The first group of pulse rectifiers (3) includes a first pulse rectifier (31) and a second pulse rectifier (32). The second group of pulse rectifiers (4) includes a first pulse rectifier (41) and a second pulse rectifier (42). The first pulse rectifier (31) and the second pulse rectifier (32) are multi-pulse diode bridge rectifiers, the first pulse rectifier (41) and the second pulse rectifier (42) are multi-pulse diode bridge rectifiers, and the four multi-pulse diode bridge rectifiers have the same structure.

[0071] The first group of autotransformers (1) is used to generate two five-phase voltages respectively and supply them to two multi-pulse diode bridge rectifiers in the first group of pulse rectifiers (3), and the second group of autotransformers (2) is used to generate two five-phase voltages respectively and supply them to two multi-pulse diode bridge rectifiers in the second group of pulse rectifiers (4). In one example, the multi-pulse diode bridge rectifiers are all 6-pulse diode bridge rectifiers, 10-pulse diode bridge rectifiers, or 12-pulse diode bridge rectifiers.

[0072] The present invention increases the fault tolerance of the circuit by adding a parallel circuit, and the parallel design is more suitable for large current hydrogen production scenarios, so that the cost-effectiveness and high power requirements in electrolytic hydrogen production can be efficiently dealt with, and it has the characteristics of low voltage and high current. The zero-sequence current suppressor can prevent the flow of zero-sequence current components, and at the same time, the zero-sequence current suppressor can allow positive-sequence and negative-sequence currents to pass freely, which is particularly important for systems with unbalanced loads or faults, and can prevent unnecessary circulating currents from being generated in the neutral line.

[0073] In one example, the turns ratio of the primary and secondary windings of the first passive pulse multiplication circuit (5) and the turns ratio of the primary and secondary windings of the second passive pulse multiplication circuit (6) are different, and have different multiplication effects, so that the first passive pulse multiplication circuit (5) and the second passive pulse multiplication circuit (6) are connected in parallel to the balancing reactor (7) to have a phase shifting effect. In one example, the two sets of transformers are non-phase shifting transformers. At the same time, an asymmetric circuit is set, and the turns ratio of the primary and secondary windings of the first passive pulse multiplication circuit (5) and the second passive pulse multiplication circuit (6) are different, and have different multiplication effects, so as to achieve a phase shifting effect without using a phase shifting transformer, that is, without the need for the two sets of transformers to be phase shifting transformers, and the circuit design process becomes simpler.

[0074] Figure 2 Each circuit in the parallel circuit shown in FIG. 1 includes two pulse rectifiers. Of course, those skilled in the art will appreciate that each circuit in the parallel circuit may also include multiple groups of pulse rectifiers. In one example, the number of parallel circuits is not limited to Figure 1 The two circuits shown in the figure may also be multiple circuits forming a parallel circuit. The first group of autotransformers (1) and the second group of autotransformers (2) may also be other suitable transformer types.

[0075] In one example, the first group of autotransformers (1) and the second group of autotransformers (2) have the same structure, wherein the current amplitudes of the upper and lower groups of three-phase alternating currents supplied by the first group of autotransformers (1) and the second group of autotransformers (2) to the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are the same.

[0076] Due to the asymmetric design of the turns ratio of the multiplication circuit winding, there is a deviation in the root mean square voltage at both ends of the balancing reactor, which may cause a DC magnetization problem. In order to make the output root mean square voltages of the two pulse multiplication circuits equal, the ratio of the turns ratio k2 of the second group of autotransformers (2) to the turns ratio k1 of the first group of autotransformers (1) is set to a first preset value. The ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) is the first preset value; wherein the first preset value is the ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) when the output root mean square voltages of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are equal. In this way, by setting the ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) to a specific value, the output root mean square voltages of the two pulse multiplication circuits are equal, thereby reducing or eliminating the DC magnetization problem caused by the asymmetric design of the turns ratio of the multiplication circuit windings.

[0077] In one example, the first group of passive pulse multiplication circuits (5) includes a balanced inductor with a secondary center tap, a first diode D1, and a second diode D2; the second group of passive pulse multiplication circuits (6) includes a balanced inductor with a secondary center tap, a third diode D3, and a fourth diode D4;

[0078] The same-name end of the secondary winding of the balancing reactor with a secondary center tap in the first passive pulse multiplication circuit (5) is connected to the anode of the first diode D1, and the opposite-name end of the lower secondary winding is connected to the anode of the second diode D2. The cathodes of D1 and D2 are connected to form the output end of the first passive pulse multiplication circuit (5) and are connected to the center point of the primary winding;

[0079] The same-name end of the upper secondary winding of the balancing reactor with the primary-secondary center tap in the second passive pulse multiplication circuit (6) is connected to the anode of the third diode D3, and the opposite-name end of the lower secondary winding is connected to the anode of the fourth diode D4. The cathodes of D3 and D4 are connected to form the output end of the second passive pulse multiplication circuit (6) and are connected to the center point of the primary winding;

[0080] The auxiliary diode of the passive pulse multiplication circuit is alternately turned on according to the relationship between the secondary voltage of the injected transformer and the load voltage, generating a specific square wave current and injecting it into the output of the rectifier. This structure increases the original 6-pulse output to 12 pulses. Two sets of asymmetrically designed 12-pulse rectification systems are connected in parallel to a balanced inductor, which can operate independently and decouple from each other, thereby achieving 24-pulse output.

[0081] The ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing inductor with a secondary center tap in the first group of passive pulse multiplication circuits (5) is different from the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing inductor with a secondary center tap in the second group of passive pulse multiplication circuits (6).

[0082] The turns ratios of the primary and secondary windings of the first passive pulse multiplication circuit (5) and the second passive pulse multiplication circuit (6) are different, and have different multiplication effects, thereby achieving a phase shifting effect without using a phase shifting transformer, that is, without the need for two sets of transformers to be phase shifting transformers, and the circuit design process becomes simpler.

[0083] In one example, the ratio of the number of turns of the secondary winding of the balancing inductor with the secondary center tap to the number of turns of the primary winding in the first group of passive pulse multiplication circuits (5) is within a first preset ratio range, and the ratio of the number of turns of the secondary winding of the balancing inductor with the secondary center tap to the number of turns of the primary winding in the second group of passive pulse multiplication circuits (6) is within a second preset ratio range;

[0084] Among them, the first preset ratio range and the second preset ratio range are different, the upper limit value of the first preset ratio range is smaller than the lower limit value of the second preset ratio range, or the upper limit value of the second preset ratio range is smaller than the lower limit value of the first preset ratio range.

[0085] In one example, the number of turns u of the secondary winding of the balancing reactor of the first group of passive pulse multiplication circuits (5) is p1 The number of turns of the primary winding u x1 The ratio m1 is 1.8-2.2; the secondary winding turns u of the balancing reactor of the second passive pulse multiplication circuit (6) p3 The number of turns of the primary winding u x2 The ratio m2 is 6-6.5. The primary-to-secondary turns ratio in the multiplier circuit is obtained by MATLAB. The relationship curve between the injection transformer turns ratio and the grid-side current harmonics. When the turns ratio satisfies m1=2.07 and m2=6.33, the minimum grid-side harmonic current is 7.58%.

[0086] The first group of autotransformers (1) and the second group of autotransformers (2) have the same winding structure, but due to the asymmetric design of the winding turns ratio of the multiplier circuit, the root mean square voltage at both ends of the balancing reactor is deviated, which may cause a DC magnetization problem. In order to make the output root mean square voltages of the two pulse multiplier circuits equal, the ratio of the turns ratio k2 of the second group of transformers (2) to the turns ratio k1 of the first group of transformers (1) is set to be 0.7-1.2. In an example, the ratio of the turns ratio k2 of the second group of autotransformers (2) to the turns ratio k1 of the first group of autotransformers (1) is 0.933. When the turns ratio satisfies m1=2.07 and m2=6.33, and the ratio of the turns ratio k2 of the second group of autotransformers (2) to the turns ratio k1 of the first group of autotransformers (1) is 0.933, the output root mean square voltages of the two pulse multiplier circuits are equal.

[0087] The process of selecting the optimal value of the primary-secondary turns ratio in the multiplier circuit is as follows: the relationship curve between the injection transformer turns ratio and the grid-side current harmonics is obtained through MATLAB. According to the relationship curve, the turns ratio corresponding to the minimum value of the grid-side harmonic current is determined, and the turns ratio is determined as the primary-secondary turns ratio in the multiplier circuit. When the primary-secondary turns ratio in the multiplier circuit is selected as described above, the best hydrogen production effect is obtained when the hydrogen production power source performs large current hydrogen production.

[0088] In one example, when the turns ratio satisfies m1=2.07 and m2=6.33, the minimum harmonic current on the grid side is 7.58%, wherein m1 is the turns u of the secondary winding of the balancing reactor of the first group of passive pulse multiplication circuits (5). p1 The number of turns of the primary winding u x1 m2 is the number of turns u of the secondary winding of the balancing reactor of the second group of passive pulse multiplication circuit (6) p3 The number of turns of the primary winding u x2 ratio.

[0089] In one example, the number of turns u of the secondary winding of the balancing reactor of the first group of passive pulse multiplication circuits (5) is p1 The number of turns of the primary winding u x1 The ratio m1 is 2.07; the number of turns u of the secondary winding of the balancing reactor of the second group of passive pulse multiplication circuit (6) p3 The number of turns of the primary winding u x2 The ratio m2 is 6.33. That is, when m1 is 2.07 and m2 is 6.33, the hydrogen production effect obtained by the hydrogen production power source is the best; in one example, when m1 is 2.07 and m2 is 6.33, the total amount (volume) of hydrogen obtained per unit time when the hydrogen production power source is used to produce hydrogen is the largest.

[0090] In one example, the ratio of the turns ratio k2 of the second set of double reverse star transformers (2) to the turns ratio k1 of the first set of double reverse star transformers (1) is 0.933. When the ratio of the turns ratio k2 of the second set of double reverse star transformers (2) to the turns ratio k1 of the first set of double reverse star transformers (1) is 0.933, the hydrogen production effect obtained when the hydrogen production power source is used to produce hydrogen is the best, that is, the total amount (volume) of hydrogen obtained per unit time when the hydrogen production power source is used to produce hydrogen is the largest.

[0091] Due to the asymmetric design of the passive pulse multiplication circuit (5) and the passive pulse multiplication circuit (6), there is a deviation in the root mean square voltage at both ends of the balancing reactor, which may lead to a DC magnetization problem. In order to make the root mean square voltage outputs of the two pulse multiplication circuits equal, the ratio of the turns ratio k2 of the second group of autotransformers (2) to the turns ratio k1 of the first group of autotransformers (1) is adjusted and set to 0.933.

[0092] Taking the first embodiment as an example, according to modal analysis, the input voltages of the two pulse multiplication circuits can be calculated as:

[0093]

[0094] Among them, u x1 、u x2 are the primary winding voltages of the two pulse multiplication circuits, k1 and k2 are the turns ratios of the two double reverse star transformers, U m is the root mean square value of the line voltage on the grid side, m1 is the number of turns u of the secondary winding of the balancing reactor of the first group of passive pulse multiplication circuits (5) p1 The number of turns of the primary winding u x1 m2 is the number of turns u of the secondary winding of the balancing reactor of the second passive pulse multiplication circuit (6). p3 The number of turns of the primary winding u x2 ratio.

[0095] Substituting the optimal turns ratio, the input voltage RMS is:

[0096] U x1_rms =0.328U d U x2_rms =0.145U d , U d is the RMS value of the DC output voltage of the circuit.

[0097] Similarly, the input current of the two pulse multiplication circuits can be calculated as:

[0098]

[0099] Among them, m1 and m2 are the ratios of the turns of the secondary winding to the primary winding in the two sets of pulse multiplication circuits; Id is the RMS value of the output current on the DC side of the circuit.

[0100] The input current rms is:

[0101] I d1_rms =I d2_rms =0.259I d I d3_rms =I d4_rms =0..309I d

[0102] According to the working principle of the injection circuit, the secondary current of the upper and lower pulse multiplication circuits can be calculated as:

[0103]

[0104] The output current RMS value is:

[0105] I p1_rms =I p2_rms =0.034I d I p3_rms =I p4_rms =0.022I d

[0106] Based on the above analysis, the capacity occupied by the two pulse multiplication circuits can be calculated:

[0107]

[0108] m1U x2_rms I p4_rms ]=4.3%

[0109] Taking the first group of passive pulse multiplication circuits as an example, by studying the interaction between the injection voltage, load voltage and rectifier current, it can be divided into three different working modes, namely: Working Mode I: See Figure 1 and Figure 6 In this mode, the secondary voltage satisfies -u p1 >u d5 , auxiliary diode D2 is turned on, D1 is reverse biased, and the current i d2 After passing through the secondary winding, it flows to the output end of the pulse multiplier circuit through D2. According to Kirchhoff's voltage law (KVL) and Kirchhoff's current law (KCL), the relationship between the input and output current and voltage of the primary and secondary sides of the pulse multiplier circuit can be expressed as:

[0110]

[0111] Among them, i d1 is the primary input current of the pulse multiplication circuit (5), i d2is the primary output current of the pulse multiplication circuit (5), i p1 is the secondary input current of the pulse multiplication circuit (5), i p2 u is the secondary output current of the pulse multiplication circuit (5); d1 、u d2 are the two output voltages of the rectifier bridge (3), u d5 、i d5 They are respectively the secondary side output voltage and output current of the pulse multiplication circuit (5).

[0112] Working mode II: See Figure 1 and Figure 7 In this mode, the absolute value of the secondary voltage satisfies |u p1 | d5 , the auxiliary diodes are reverse biased, and the current i d1 、i d2 The midpoint of the primary winding is directly connected to the output end of the pulse multiplier circuit. According to Kirchhoff's voltage law (KVL) and Kirchhoff's current law (KCL), the relationship between the primary and secondary input and output current and voltage of the pulse multiplier circuit can be expressed as:

[0113] i d1 =i d2 =0,i p1 =i p2 =0,

[0114] Among them, i d1 is the primary input current of the pulse multiplication circuit (5), i d2 is the primary output current of the pulse multiplication circuit (5), i p1 is the secondary input current of the pulse multiplication circuit (5), i p2 u is the secondary output current of the pulse multiplication circuit (5); d1 、u d2 are the two output voltages of the rectifier bridge (3), u d5 、i d5 They are respectively the secondary side output voltage and output current of the pulse multiplication circuit (5).

[0115] Working mode III: See Figure 1 and Figure 8 In this mode, the secondary voltage satisfies u p1 >u d5 , auxiliary diode D1 is turned on, D2 is reverse biased, and the current i d1 After passing through the secondary winding, it flows to the output end of the pulse multiplier circuit through D1. According to Kirchhoff's voltage law (KVL) and Kirchhoff's current law (KCL), the relationship between the input and output current and voltage of the primary and secondary sides of the pulse multiplier circuit can be expressed as: ​

[0116]

[0117] Among them, i d1 is the primary input current of the pulse multiplication circuit (5), i d2 is the primary output current of the pulse multiplication circuit (5), i p1 is the secondary input current of the pulse multiplication circuit (5), i p2 u is the secondary output current of the pulse multiplication circuit (5); d1 、u d2 are the two output voltages of the rectifier bridge (3), u d5 、i d5 They are respectively the secondary side output voltage and output current of the pulse multiplication circuit (5).

[0118] The two groups of asymmetrically designed multi-pulse rectifier systems are connected in parallel. After the balancing reactor acts, the multi-pulse output current and the DC side current of the circuit satisfy the relationship:

[0119]

[0120] Among them, I d5 is the RMS value of the output current of the passive pulse multiplier circuit (5), I d5 is the root mean square of the output current of the passive pulse multiplication circuit (6); i d6 is the output current of the passive pulse multiplier circuit (6), I d Output current for the circuit.

[0121] The parallel design of the present invention has the characteristics of low voltage and high current, enhances the circuit fault tolerance, and is more suitable for large current hydrogen production scenarios. The two small-capacity injection circuits of the present invention can achieve phase shift through different turn ratio values, so there is no need to use a phase-shifting transformer, that is, the first set of double reverse star transformers (1) and the second set of double reverse star transformers (2) do not need to phase-shift the three-phase power supply to generate three-phase alternating current with a certain phase difference, which makes the circuit design process simpler than directly shifting the phase through the transformer.

[0122] Through the analysis of the above embodiments and comprehensive consideration of the implementation effects of the present invention in many aspects, it is determined that it has higher stability, lower cost and complexity, greater ability to handle large currents, smaller conduction losses, can achieve efficient hydrogen production, and is suitable for high-power hydrogen production systems.

[0123] The asymmetric parallel high-power three-phase hydrogen production power supply of the present invention has a parallel circuit, which enables it to efficiently cope with the cost-effectiveness and high power requirements in electrolytic hydrogen production, and has the characteristics of low voltage and high current. The present invention changes the turns ratio of two balancing reactors with secondary windings so that the two achieve different pulse multiplication effects. After the voltage is divided by the balancing reactor, the grid-side current finally shows 24 pulses that are closer to a sine wave, and the output current ripple rate of the rectifier is significantly reduced. The new asymmetric parallel 24-pulse rectifier is suitable for water electrolysis hydrogen production system.

[0124] In summary, the present invention only needs to connect two asymmetric circuits without phase-shifting transformers in parallel, and inject the current harmonics generated by the harmonic injection circuit into the DC side of the rectifier, so that the input current is closer to a sine wave, and the output current ripple rate of the rectifier reaches 2.5%, which significantly improves the power quality. In addition, these two small-capacity injection circuits can achieve phase shift through different turn ratio values, so there is no need to use a phase-shifting transformer. For example, the first group of double reverse star transformers (1) and the second group of double reverse star transformers (2) do not need to phase-shift the three-phase power supply to generate three-phase alternating current with a certain angle difference in phase. Compared with directly shifting the phase through the transformer, the circuit design process becomes simpler, and the use of an autotransformer also reduces the volume and weight of the entire hydrogen production power supply. In addition, the parallel design enhances the fault tolerance of the circuit and is more suitable for large current hydrogen production scenarios.

[0125] In summary, the beneficial effects of the present invention are:

[0126] 1. Compared with the existing three-phase high-power hydrogen production power supply, the present invention only needs two small-capacity injection circuits to make the grid-side input current closer to a sine wave and achieve a better harmonic suppression effect. Therefore, this solution is highly efficient, and the current passing through the auxiliary unit only accounts for 3.4% of the output current.

[0127] 2. From the perspective of design complexity, the complexity of the rectifier structure mainly depends on the complexity of the phase-shifting transformer. The present invention adopts two specially designed asymmetric circuit structures to achieve the effect of phase shift by controlling the turns ratio of the secondary winding balancing reactor, which eliminates the need for transformer phase shifting design and helps to reduce the complexity of the design of this article.

[0128] 3. Compared with the existing multi-pulse rectifier, the asymmetric circuit parallel structure adopted in the present invention has a strong fault tolerance capability, making the system more stable. It also replaces the need for multiple phase-shifting transformers and significantly reduces the total rated magnetic value.

[0129] 4. From the perspective of cost, the total cost of the multi-pulse rectifier is mainly determined by the capacity of the magnetic devices, making the total cost proportional to the capacity of these devices. The power capacity of the auxiliary circuit used in the present invention only accounts for 6.6% and 4.3% respectively, effectively solving the cost-effectiveness in electrolytic hydrogen production.

[0130] 5. From the application scenario, hydrogen production requires low voltage and high current, because the hydrogen production rate is almost proportional to the current amplitude. Therefore, high current levels prevent semiconductor devices from being directly connected in series with the load. Compared with the existing multi-pulse rectifier, the parallel structure of the present invention has smaller conduction loss and greater ability to handle large currents, and is more suitable for water electrolysis hydrogen production systems.

[0131] In addition, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0132] In addition, in the present invention, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An asymmetric parallel three-phase hydrogen production power supply, characterized in that: include: A first group of transformer and rectifier units, a second group of transformer and rectifier units, a first group of passive pulse multiplier circuits (5), a second group of passive pulse multiplier circuits (6) and a balancing reactor (7); wherein the first group of transformer and rectifier units comprises a first group of transformers (1) and a first group of pulse rectifiers (3), and the second group of transformer and rectifier units comprises a second group of transformers (2) and a second group of pulse rectifiers (4); The first transformer group (1) and the second transformer group (2) have the same structure. The first transformer group (1) is used to supply three-phase power to the first pulse rectifier group (3), and the second transformer group (2) is used to supply three-phase power to the second pulse rectifier group (4). The current amplitudes of the upper and lower three-phase alternating currents respectively supplied to the first pulse rectifier group (3) and the second pulse rectifier group (4) are the same, and the two transformer groups are non-phase shifting transformers. The output end of the first group of pulse rectifiers (3) is connected to the input end of the first group of passive pulse multiplication circuits (5), the output end of the second group of pulse rectifiers (4) is connected to the input end of the second group of passive pulse multiplication circuits (6), and the output ends of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are respectively connected to the two sides of the balancing reactor (7); The center point of the balancing reactor (7), the first group of transformer-rectifier units and the second transformer-rectifier unit are respectively connected to the positive and negative sides of an electrolyzer for producing hydrogen by electrolysis; The turns ratio of the primary and secondary windings of the first group of passive pulse multiplication circuits (5) and the turns ratio of the primary and secondary windings of the second group of passive pulse multiplication circuits (6) are different, and have different multiplication effects, so that the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are connected in parallel to the balancing reactor (7) to have a phase shift effect.

2. The asymmetric parallel three-phase hydrogen production power supply according to claim 1 is characterized in that: The ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) is a first preset value; Wherein, the first preset value is the ratio of the turns ratio of the first group of transformers (1) to the turns ratio of the second group of transformers (2) when the root mean square output voltages of the first group of passive pulse multiplication circuits (5) and the second group of passive pulse multiplication circuits (6) are equal.

3. The asymmetric parallel three-phase hydrogen production power supply according to claim 1 is characterized in that: The first group of passive pulse multiplication circuits (5) comprises a balanced inductor with a secondary center tap, a first diode D1 and a second diode D2; the second group of passive pulse multiplication circuits (6) comprises a balanced inductor with a secondary center tap, a third diode D3 and a fourth diode D4; The same-name end of the secondary winding of the balancing reactor with a secondary center tap in the first group of passive pulse multiplication circuits (5) is connected to the anode of the first diode D1, and the opposite-name end of the lower secondary winding is connected to the anode of the second diode D2. The cathodes of D1 and D2 are connected to form the output end of the first group of passive pulse multiplication circuits (5) and are connected to the center point of the primary winding; The same-name end of the upper secondary winding of the balancing reactor with the primary-secondary center tap in the second group of passive pulse multiplication circuits (6) is connected to the anode of the third diode D3, and the opposite-name end of the lower secondary winding is connected to the anode of the fourth diode D4. The cathodes of D3 and D4 are connected to form the output end of the second group of passive pulse multiplication circuits (6) and are connected to the center point of the primary winding; The ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing inductor with a secondary center tap in the first group of passive pulse multiplication circuits (5) is different from the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing inductor with a secondary center tap in the second group of passive pulse multiplication circuits (6).

4. The asymmetric parallel three-phase hydrogen production power supply according to claim 3 is characterized in that: The ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing reactor with a secondary center tap in the first group of passive pulse multiplication circuits (5) is within a first preset ratio range, and the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the balancing reactor with a secondary center tap in the second group of passive pulse multiplication circuits (6) is within a second preset ratio range; Among them, the first preset ratio range and the second preset ratio range are different, the upper limit value of the first preset ratio range is smaller than the lower limit value of the second preset ratio range, or the upper limit value of the second preset ratio range is smaller than the lower limit value of the first preset ratio range.

5. The asymmetric parallel three-phase hydrogen production power supply according to any one of claims 1 to 4, characterized in that: The first group of transformer-rectifier units and the second group of transformer-rectifier units are connected to the electrolytic cell at one side which is the neutral point of the first group of transformers (1) and the second group of transformers (2); The center point of the balancing reactor (7) is connected to the positive side of the electrolytic cell, and the neutral points of the first group of transformers (1) and the second group of transformers (2) are connected to the negative side of the electrolytic cell.

6. The asymmetric parallel three-phase hydrogen production power supply according to claim 8 is characterized in that: The first set of transformers (1) is a double reverse star transformer, and the second set of transformers (2) is a double reverse star transformer; The first group of pulse rectifiers (3) is a multi-pulse diode bridge rectifier, and the second group of pulse rectifiers (4) is a multi-pulse diode bridge rectifier. The two groups of multi-pulse diode bridge rectifiers have the same structure. The two groups of stars on the secondary side of each double reverse star transformer are respectively connected to the upper and lower half waves of a rectifier connected thereto.

7. The asymmetric parallel three-phase hydrogen production power supply according to any one of claims 1 to 4, characterized in that: The first group of transformer-rectifier units and the second group of transformer-rectifier units are connected to the side of the electrolytic cell which is the output end of the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4); The center point of the balancing reactor (7) is connected to the positive side of the electrolytic cell, and the output ends of the first group of pulse rectifiers (3) and the second group of pulse rectifiers (4) are connected to the negative side of the electrolytic cell.

8. The asymmetric parallel three-phase hydrogen production power supply according to claim 7 is characterized in that: The power supply further comprises a first group of zero-sequence current suppressors (8) arranged between the first group of pulse rectifiers (3) and the first group of passive pulse multiplication circuits (5), and a second group of zero-sequence current suppressors (9) arranged between the second group of pulse rectifiers (4) and the second group of passive pulse multiplication circuits (6), wherein one pulse rectifier is connected to one zero-sequence current suppressor. The positive output end of the first group of zero-sequence current suppressors (8) is connected to the input end of the first group of passive pulse multiplication circuits (5), and the positive output end of the second group of zero-sequence current suppressors (9) is connected to the input end of the second group of passive pulse multiplication circuits (6); The center point of the balancing reactor (7) and the negative output ends of the first group of zero-sequence current suppressors (8) and the second group of zero-sequence current suppressors (9) are respectively connected to the positive and negative sides of an electrolytic cell for producing hydrogen by electrolysis.

9. The asymmetric parallel three-phase hydrogen production power supply according to claim 8, characterized in that: The first set of transformers (1) is a first set of autotransformers, and the second set of transformers (2) is a second set of autotransformers; The first group of pulse rectifiers (3) includes two multi-pulse diode bridge rectifiers connected in parallel, and the second group of pulse rectifiers (4) includes two multi-pulse diode bridge rectifiers connected in parallel, and the multi-pulse diode bridge rectifiers have the same structure; The first group of autotransformers is used to generate two five-phase voltages respectively and supply them to two multi-pulse diode bridge rectifiers in the first group of pulse rectifiers (3); the second group of autotransformers is used to generate two five-phase voltages respectively and supply them to two multi-pulse diode bridge rectifiers in the second group of pulse rectifiers (4).

10. The asymmetric parallel three-phase hydrogen production power supply according to claim 4, characterized in that: The number of turns u of the secondary winding of the balancing reactor of the first group of passive pulse multiplication circuits (5) is p1 The number of turns of the primary winding u x1 The ratio m1 is 1.8-2.2; the number of turns u of the secondary winding of the balancing reactor of the second group of passive pulse multiplication circuits (6) p3 The number of turns of the primary winding u x2 The ratio m2 is 6-6.5.

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