36-pulse hydrogen production converter based on controllable pulse multiplication and balancing reactor

Abstract

A 36-pulse hydrogen production converter based on a controllable pulse multiplication balancing reactor belongs to the field of power electronics technology. It addresses the problems of high input current THD and output voltage ripple, as well as the large number of high-current thyristors required in existing 24-pulse thyristor-rectified hydrogen production converters. The present invention constructs a 36-pulse hydrogen production converter consisting of a nine-phase half-wave thyristor bridge, an auxiliary single-phase thyristor rectifier bridge, and a balancing reactor with a secondary side. The controllable pulse multiplication balancing reactor is composed of the balancing reactor with a secondary side and the auxiliary single-phase thyristor rectifier bridge. By controlling the thyristors in the nine-phase half-wave thyristor bridge and the auxiliary single-phase thyristor rectifier bridge and rationally designing the primary and secondary winding turns ratios of the balancing reactor with a secondary side, a 36-pulse hydrogen production converter can be achieved. The rectifier solution of the present invention requires only 18 high-current thyristors and is primarily suitable for renewable energy hydrogen production applications with high power quality requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics. Background Art

[0002] In large-scale renewable energy hydrogen production systems, the power level of the hydrogen converter is typically in the MW or even GW range. To meet the high power requirements of the hydrogen production rectifier, a 12-pulse thyristor-based rectifier is often used. This solution offers advantages such as high efficiency, mature technology, and low cost. However, it suffers from low power factor, high input current harmonic content, and large output voltage ripple. To address these issues, researchers have proposed a variety of solutions, which can be categorized into three types. The first is a hydrogen production converter based on a 12-pulse uncontrolled rectifier and a DC chopper. This solution achieves a high power factor and low output voltage ripple, but when used alone, the input current still contains significant harmonics. The second is to use multiple three-phase PWM rectifiers in parallel to form a high-power hydrogen production rectifier. This solution can achieve a high power factor and make the input current nearly sinusoidal. However, operating multiple three-phase PWM rectifiers in parallel complicates the control and commissioning of the hydrogen production rectifier, and the hydrogen production rectifier has a weak overload capacity. A third approach is to increase the pulse count of the hydrogen production rectifier to 24 pulses to further suppress input current harmonics and output voltage ripple. However, this solution still results in high input current THD and output voltage ripple, and requires 24 high-current thyristors, a relatively large number. Therefore, these issues urgently need to be addressed. Summary of the Invention

[0003] The present invention aims to solve the problems of high input current THD and output voltage ripple in existing 24-pulse thyristor rectified hydrogen production converters, as well as the large number of high-current thyristors required. The present invention provides a 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor.

[0004] The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor includes a first nine-phase phase-shifting transformer, a second nine-phase phase-shifting transformer, a first nine-phase half-wave thyristor bridge, and a second nine-phase half-wave thyristor bridge. The first nine-phase phase-shifting transformer and the second nine-phase phase-shifting transformer are used to phase-shift the three-phase voltage output by the power grid to generate two sets of nine-phase voltages with the same amplitude and a phase difference of 20°. The two sets of nine-phase voltages are respectively input into the first nine-phase half-wave thyristor bridge and the second nine-phase half-wave thyristor bridge for rectification.

[0005] The 36-pulse hydrogen converter also includes an inductor L s , trigger signal generator and controllable pulse multiplication balancing reactor;

[0006] The controllable pulse multiplying balancing reactor is used to multiply the pulse number of the three-phase current output by the power grid from 18 pulses to 36 pulses, and the controllable pulse multiplying balancing reactor includes a balancing reactor with a secondary side and an auxiliary single-phase thyristor rectifier bridge. The turns ratio of the primary and secondary windings of the balancing reactor with a secondary side is 33;

[0007] The positive output terminals of the first nine-phase half-wave thyristor bridge and the second nine-phase half-wave thyristor bridge are respectively connected to the same-name terminal and the opposite-name terminal of the primary winding of the balancing reactor with the secondary side;

[0008] The center output of the primary winding of the balancing reactor with the secondary side is connected to the DC output of the auxiliary single-phase thyristor rectifier bridge and the inductor L s The same-name end and the opposite-name end of the secondary winding of the balancing reactor with the secondary side are respectively connected to the first and second AC input terminals of the auxiliary single-phase thyristor rectifier bridge. The DC input terminal of the auxiliary single-phase thyristor rectifier bridge is simultaneously connected to the neutral point of the first nine-phase phase-shifting transformer and the second nine-phase phase-shifting transformer, as well as the negative pole of the electrolytic cell. The positive pole of the electrolytic cell is connected to the inductor L. s The other end of the connection;

[0009] The trigger signal generator is used to perform zero-crossing detection on the phase of the A-phase voltage in the three-phase voltage output by the power grid, and when the phase of the A-phase voltage is 0 during the process of changing from negative to positive, it generates three sets of trigger signals to control the thyristor control ends of each thyristor in the first nine-phase half-wave thyristor bridge, the second nine-phase half-wave thyristor bridge and the auxiliary single-phase thyristor rectifier bridge respectively.

[0010] Preferably, the first group of trigger signals for controlling the first nine-phase half-wave thyristor bridge includes nine trigger signals, and the nine trigger signals respectively control the nine thyristors of the first nine-phase half-wave thyristor bridge;

[0011] There is a one-to-one correspondence between the nine thyristors of the first nine-phase half-wave thyristor bridge and the nine-phase voltages output by the first nine-phase half-wave thyristor bridge, and the conduction angle of the thyristor corresponding to the first phase voltage output by the first nine-phase half-wave thyristor bridge is α, and the phase angle of the trigger signal of the thyristor corresponding to the first phase voltage is: when the phase of the A phase voltage in the three-phase voltage output by the power grid changes from negative to positive and is 0, the phase angle is obtained by shifting the phase by α;

[0012] The phase angles of the trigger signals of the nine thyristors corresponding to the nine-phase voltage output by the first nine-phase half-wave thyristor bridge increase sequentially from the first phase to the ninth phase, and the phase angles of the trigger signals of the two thyristors corresponding to the two adjacent phase voltages differ by 40°;

[0013] A set of trigger signals for controlling the second nine-phase half-wave thyristor bridge includes nine trigger signals, and the nine trigger signals respectively control the nine thyristors of the second nine-phase half-wave thyristor bridge;

[0014] The phase angle of the trigger signal of the thyristor corresponding to each phase voltage in the second nine-phase half-wave thyristor bridge differs by 20° from the phase angle of the trigger signal of the thyristor corresponding to the corresponding phase voltage in the first nine-phase half-wave thyristor bridge, and the phase angle of the trigger signal of the thyristor in the second nine-phase half-wave thyristor bridge corresponding to the same-phase voltage is greater than the phase angle of the trigger signal of the thyristor in the first nine-phase half-wave thyristor bridge;

[0015] A set of trigger signals for controlling the auxiliary single-phase thyristor rectifier bridge includes four trigger signals, which respectively control the four thyristors of the auxiliary single-phase thyristor rectifier bridge. The four thyristors are diagonally conductive, and the trigger signals received by the two thyristors located at the diagonals are the same;

[0016] The phase angle of the trigger signal received by the thyristor in the upper arm of the same bridge arm in the auxiliary single-phase thyristor rectifier bridge is β1, and β1=α+10°, and the phase angle of the trigger signal received by the thyristor in the lower arm of the same bridge arm is β2, and β2=α+30°.

[0017] Preferably, the voltage with the smallest phase output by the first nine-phase half-wave thyristor bridge is used as the first phase voltage output by the first nine-phase half-wave thyristor bridge.

[0018] Preferably, the conduction period of the thyristors in the auxiliary single-phase thyristor rectifier bridge is 1 / 9 of the conduction period of the thyristors in the first nine-phase half-wave thyristor bridge.

[0019] Preferably, the turns ratio between the primary and secondary windings of the balancing reactor with a secondary winding is 3:3.

[0020] Preferably, the auxiliary single-phase thyristor rectifier bridge includes thyristor T1, thyristor T2, thyristor T3 and thyristor T4;

[0021] After the anode of thyristor T1 is connected to the cathode of thyristor T3, it serves as the first AC input terminal of the auxiliary single-phase thyristor rectifier bridge;

[0022] After the anode of thyristor T2 is connected to the cathode of thyristor T4, it serves as the second AC input terminal of the auxiliary single-phase thyristor rectifier bridge;

[0023] After the cathode of thyristor T1 is connected to the cathode of thyristor T2, it serves as the DC output end of the auxiliary single-phase thyristor rectifier bridge;

[0024] After the anode of the thyristor T3 is connected to the anode of the thyristor T4, it serves as the DC input terminal of the auxiliary single-phase thyristor rectifier bridge.

[0025] Preferably, the voltage across the secondary winding of the balancing reactor with a secondary side is u s , the voltage across the electrolytic cell is ud The controllable pulse multiplication balancing reactor includes three working modes, specifically:

[0026] Working mode Ⅰ: When -u s >u d At this time, all thyristors in the first nine-phase half-wave thyristor bridge connected to the same-name end of the primary winding of the balancing reactor with the secondary side are in the reverse blocking state, and no current flows; the second nine-phase half-wave thyristor bridge connected to the opposite-name end of the primary winding of the balancing reactor with the secondary side is in the forward conduction state, and current flows; at the same time, in the auxiliary single-phase thyristor rectifier bridge connected to the secondary winding of the balancing reactor with the secondary side, thyristors T1 and T4 are in the reverse blocking state, and no current flows, while thyristors T2 and T3 are in the forward conduction state, and current flows. The auxiliary single-phase thyristor rectifier bridge and the second nine-phase half-wave thyristor bridge jointly supply power to the electrolyzer;

[0027] Working mode II: When |u s | d When the first nine-phase half-wave thyristor bridge connected to the same-name end of the primary winding of the balancing reactor with the secondary side and the second nine-phase half-wave thyristor bridge connected to the opposite-name end of the primary winding of the balancing reactor with the secondary side are both in the forward conduction state, with current flowing through them. At the same time, the thyristors T1 to T4 in the auxiliary single-phase thyristor rectifier bridge connected to the secondary winding of the balancing reactor with the secondary side are in the reverse blocking state, with no current flowing through them. The first nine-phase half-wave thyristor bridge and the second nine-phase half-wave thyristor bridge jointly supply power to the electrolytic cell.

[0028] Working mode III: When u s >u d At this time, the first nine-phase half-wave thyristor bridge connected to the same-name end of the primary winding of the balancing reactor with the secondary side is in the forward conduction state, and current flows through it; the second nine-phase half-wave thyristor bridge connected to the opposite-name end of the primary winding of the balancing reactor with the secondary side is in the reverse blocking state, and no current flows through it. At the same time, in the auxiliary single-phase thyristor rectifier bridge connected to the secondary winding of the balancing reactor with the secondary side, thyristors T2 and T3 are in the reverse blocking state, and no current flows through it, and thyristors T1 and T4 are in the forward conduction state, and current flows through it. The auxiliary single-phase thyristor rectifier bridge and the first nine-phase half-wave thyristor bridge jointly supply power to the electrolyzer.

[0029] Advantages of the present invention:

[0030] ​The present invention provides a 36-pulse hydrogen production converter based on a controllable pulse multiplication balancing reactor. This converter boasts low input current THD, minimal conduction losses, and low output voltage ripple. It simply requires the introduction of a controllable pulse multiplication balancing reactor on the DC side of two parallel nine-phase half-wave thyristor bridges to modulate the output current states of the first and second nine-phase half-wave thyristor bridges, thereby doubling the pulse count of the parallel 18-pulse rectifier. This effectively suppresses the input current harmonics and output voltage ripple of the parallel 18-pulse rectifier, ensuring that the rectifier's input current THD meets the requirements for high-power hydrogen production. The parallel 18-pulse rectifier consists of a first nine-phase half-wave thyristor bridge, a second nine-phase half-wave thyristor bridge, and a balancing reactor with a secondary side.

[0031] The 36-pulse hydrogen production converter based on a controllable pulse multiplication balancing reactor described in this invention offers advantages over existing 24-pulse thyristor-rectified hydrogen production converters, including fewer high-current thyristors, better harmonic suppression, and reduced output voltage ripple. This converter utilizes only two simple nine-phase phase-shifting transformers, two nine-phase half-wave thyristor bridges, an auxiliary single-phase thyristor rectifier bridge, and a balancing reactor with a secondary side. By rationally designing the turns ratio of the balancing reactor with a secondary side, the rectifier pulse count can be doubled. This converter is primarily intended for applications requiring high power quality from the hydrogen production converter. It boasts a simple circuit structure, low cost, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of the 36-pulse hydrogen production converter based on the controllable pulse multiplication and balancing reactor of the present invention;

[0033] Figure 2 This is a schematic diagram of the current loop when the controllable pulse multiplying balancing reactor operates in Mode I;

[0034] Figure 3 This is a schematic diagram of the current loop when the controllable pulse multiplying balancing reactor operates in mode II;

[0035] Figure 4 This is a schematic diagram of the current loop when the controllable pulse multiplying balancing reactor operates in mode III;

[0036] in, Figures 1 to 4 middle,

[0037] i A 、i B 、i C are the three-phase currents a, b, and c output from the power grid respectively;

[0038] u A 、u B 、u Care the three-phase voltages a, b, and c output from the power grid respectively;

[0039] i d1 is the current outputted from the positive polarity output terminal of the first nine-phase half-wave thyristor bridge 3;

[0040] i d2 is the current outputted from the positive polarity output terminal of the second nine-phase half-wave thyristor bridge 4;

[0041] I d is the current input to the electrolytic cell 7;

[0042] u d1 is the output voltage of the first nine-phase half-wave thyristor bridge 3;

[0043] u d2 is the output voltage of the second nine-phase half-wave thyristor bridge 4;

[0044] u d is the voltage across the electrolytic cell 7;

[0045] u p is the voltage across the primary winding of the balancing reactor 5 with a secondary side;

[0046] u s is the voltage across the secondary winding of the balancing reactor 5 with a secondary side;

[0047] i s It is the current output by the secondary winding of the balancing inductor 5 with a secondary side. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0049] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0050] Specific implementation method 1. Combination Figure 1As shown, the 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to the first embodiment includes a first nine-phase phase-shifting transformer 1, a second nine-phase phase-shifting transformer 2, a first nine-phase half-wave thyristor bridge 3, and a second nine-phase half-wave thyristor bridge 4. The first nine-phase phase-shifting transformer 1 and the second nine-phase phase-shifting transformer 2 are used to phase-shift the three-phase voltage output by the power grid to generate two sets of nine-phase voltages with the same amplitude and a phase difference of 20°. The two sets of nine-phase voltages are respectively input to the first nine-phase half-wave thyristor bridge 3 and the second nine-phase half-wave thyristor bridge 4 for rectification.

[0051] The 36-pulse hydrogen converter also includes an inductor L s , a trigger signal generator 8 and a controllable pulse multiplication balancing reactor;

[0052] The controllable pulse multiplication balancing reactor is used to multiply the number of pulses of the three-phase current output by the power grid from 18 pulses to 36 pulses, and the controllable pulse multiplication balancing reactor includes a balancing reactor 5 with a secondary side and an auxiliary single-phase thyristor rectifier bridge 6;

[0053] The positive output terminals of the first nine-phase half-wave thyristor bridge 3 and the second nine-phase half-wave thyristor bridge 4 are respectively connected to the same-name terminal and the opposite-name terminal of the primary winding of the balancing inductor 5 with a secondary side;

[0054] The central output of the primary winding of the balancing reactor 5 with the secondary side is connected to the DC output end of the auxiliary single-phase thyristor rectifier bridge 6 and the inductor L s The same-name terminal and the opposite-name terminal of the secondary winding of the balancing inductor 5 with a secondary side are respectively connected to the first and second AC input terminals of the auxiliary single-phase thyristor rectifier bridge 6, and the DC input terminal of the auxiliary single-phase thyristor rectifier bridge 6 is simultaneously connected to the neutral point of the first nine-phase phase-shifting transformer 1 and the second nine-phase phase-shifting transformer 2, and the negative electrode of the electrolytic cell 7, and the positive electrode of the electrolytic cell 7 is connected to the inductor L. s The other end of the connection;

[0055] The trigger signal generator 8 is used to perform zero-crossing detection on the phase of the A-phase voltage in the three-phase voltage output by the power grid, and when the phase of the A-phase voltage is 0 during the process of changing from negative to positive, it generates three sets of trigger signals to control the thyristor control ends of each thyristor in the first nine-phase half-wave thyristor bridge 3, the second nine-phase half-wave thyristor bridge 4 and the auxiliary single-phase thyristor rectifier bridge 6 respectively.

[0056] In a specific application, the turns ratio of the primary and secondary windings of the balancing reactor 5 with a secondary winding is 3:3.

[0057] The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor described in this embodiment simply introduces a controllable pulse multiplication and balancing reactor on the DC side of two parallel nine-phase half-wave thyristor bridges to modulate the output current states of the first and second nine-phase half-wave thyristor bridges, thereby doubling the pulse count of the parallel 18-pulse rectifier. This effectively suppresses the input current harmonics and output voltage ripple of the parallel 18-pulse rectifier, ensuring that the rectifier's input current THD meets the requirements of high-power hydrogen production. The converter has the advantages of low input current THD, low conduction losses, and low output voltage ripple. The parallel 18-pulse rectifier comprises a first nine-phase half-wave thyristor bridge, a second nine-phase half-wave thyristor bridge, and a balancing reactor 5 with a secondary side.

[0058] The 36-pulse hydrogen production converter based on a controllable pulse multiplication balancing reactor described in this invention, compared to existing hydrogen production converters based on 24-pulse thyristor rectification, requires fewer high-current thyristors, offers superior harmonic suppression, and reduces output voltage ripple. The present invention utilizes only two simple nine-phase phase-shifting transformers, two nine-phase half-wave thyristor bridges, an auxiliary single-phase thyristor rectifier bridge 6, and a balancing reactor 5 with a secondary side. By rationally designing the turns ratio of the balancing reactor with a secondary side, the rectifier pulse count can be doubled. This converter is primarily intended for applications requiring high power quality from the hydrogen production converter. It boasts a simple circuit structure, low cost, and high reliability.

[0059] Furthermore, the first group of trigger signals for controlling the first nine-phase half-wave thyristor bridge 3 includes nine trigger signals, and the nine trigger signals respectively control the nine thyristors of the first nine-phase half-wave thyristor bridge 3;

[0060] There is a one-to-one correspondence between the nine thyristors of the first nine-phase half-wave thyristor bridge 3 and the nine-phase voltages output by it, and the conduction angle of the thyristor corresponding to the first phase voltage output by the first nine-phase half-wave thyristor bridge 3 is α, and the phase angle of the trigger signal of the thyristor corresponding to the first phase voltage is: when the phase of the A phase voltage in the three-phase voltage output by the power grid changes from negative to positive and the phase is 0, the phase angle is obtained by a phase shift of α;

[0061] In a specific application, the voltage with the smallest phase output by the first nine-phase half-wave thyristor bridge 3 is used as the first phase voltage output by the first nine-phase half-wave thyristor bridge 3;

[0062] The phase angles of the trigger signals of the nine thyristors corresponding to the nine-phase voltage output by the first nine-phase half-wave thyristor bridge 3 increase sequentially from the first phase to the ninth phase, and the phase angles of the trigger signals of the two thyristors corresponding to the two adjacent phase voltages differ by 40°;

[0063] A set of trigger signals for controlling the second nine-phase half-wave thyristor bridge 4 includes nine trigger signals, and the nine trigger signals respectively control the nine thyristors of the second nine-phase half-wave thyristor bridge 4;

[0064] The phase angle of the trigger signal of the thyristor corresponding to each phase voltage in the second nine-phase half-wave thyristor bridge 4 differs by 20° from the phase angle of the trigger signal of the thyristor corresponding to the corresponding phase voltage in the first nine-phase half-wave thyristor bridge 3, and the phase angle of the trigger signal of the thyristor in the second nine-phase half-wave thyristor bridge 4 corresponding to the same-phase voltage is greater than the phase angle of the trigger signal of the thyristor in the first nine-phase half-wave thyristor bridge 3;

[0065] A set of trigger signals for controlling the auxiliary single-phase thyristor rectifier bridge 6 includes four trigger signals, which respectively control the four thyristors of the auxiliary single-phase thyristor rectifier bridge 6. The four thyristors are diagonally conductive, and the trigger signals received by the two thyristors located at the diagonals are the same;

[0066] The phase angle of the trigger signal received by the thyristor in the upper arm of the same bridge arm in the auxiliary single-phase thyristor rectifier bridge 6 is β1, and β1=α+10°, and the phase angle of the trigger signal received by the thyristor in the lower arm of the same bridge arm is β2, and β2=α+30°.

[0067] In this preferred embodiment, the purpose of setting the phase angle of the trigger signal is to regulate the grid-side input current and DC-side output voltage levels with the help of the phase angle of the trigger signal, thereby significantly reducing the complexity of adjusting the input current and DC-side output voltage.

[0068] In specific applications, the conduction period of the thyristors in the auxiliary single-phase thyristor rectifier bridge 6 is 1 / 9 of the conduction period of the thyristors in the first nine-phase half-wave thyristor bridge 3. This setting keeps the rectifier always working in the standard 36-pulse state.

[0069] See also Figure 1 , further defining the structure of the auxiliary single-phase thyristor rectifier bridge 6, the auxiliary single-phase thyristor rectifier bridge 6 including a thyristor T1, a thyristor T2, a thyristor T3 and a thyristor T4;

[0070] After the anode of thyristor T1 is connected to the cathode of thyristor T3, it serves as the first AC input terminal of the auxiliary single-phase thyristor rectifier bridge 6;

[0071] After the anode of thyristor T2 is connected to the cathode of thyristor T4, it serves as the second AC input terminal of the auxiliary single-phase thyristor rectifier bridge 6;

[0072] After the cathode of thyristor T1 is connected to the cathode of thyristor T2, it serves as the DC output end of the auxiliary single-phase thyristor rectifier bridge 6;

[0073] After the anode of the thyristor T3 is connected to the anode of the thyristor T4 , it serves as a DC input terminal of the auxiliary single-phase thyristor rectifier bridge 6 .

[0074] The voltage across the secondary winding of the balancing reactor 5 with a secondary side is u s , the voltage across the electrolytic cell 7 is u d The controllable pulse multiplication balancing reactor includes three working modes, specifically:

[0075] Working mode Ⅰ: When -u s >u d At this time, all thyristors in the first nine-phase half-wave thyristor bridge 3 connected to the same-name end of the primary winding of the balancing reactor 5 with a secondary side are in a reverse blocking state, and no current flows; the second nine-phase half-wave thyristor bridge 4 connected to the opposite-name end of the primary winding of the balancing reactor 5 with a secondary side is in a forward conduction state, and current flows; at the same time, in the auxiliary single-phase thyristor rectifier bridge 6 connected to the secondary winding of the balancing reactor 5 with a secondary side, thyristors T1 and T4 are in a reverse blocking state, and no current flows, while thyristors T2 and T3 are in a forward conduction state, and current flows. The auxiliary single-phase thyristor rectifier bridge 6 and the second nine-phase half-wave thyristor bridge 4 jointly supply power to the electrolytic cell 7;

[0076] Working mode II: When |u s | d At this time, the first nine-phase half-wave thyristor bridge 3 connected to the same-name end of the primary winding of the balancing reactor 5 with a secondary side and the second nine-phase half-wave thyristor bridge 4 connected to the opposite-name end of the primary winding of the balancing reactor 5 with a secondary side are both in a forward conduction state, with current flowing through them. At the same time, the thyristors T1 to T4 in the auxiliary single-phase thyristor rectifier bridge 6 connected to the secondary winding of the balancing reactor 5 with a secondary side are in a reverse blocking state, with no current flowing through them. The first nine-phase half-wave thyristor bridge 3 and the second nine-phase half-wave thyristor bridge 4 jointly supply power to the electrolytic cell 7.

[0077] Working mode III: When u s >u d At this time, the first nine-phase half-wave thyristor bridge 3 connected to the same-name end of the primary winding of the balancing reactor 5 with a secondary side is in a forward conduction state, and current flows through it; the second nine-phase half-wave thyristor bridge 4 connected to the opposite-name end of the primary winding of the balancing reactor 5 with a secondary side is in a reverse blocking state, and no current flows through it. At the same time, in the auxiliary single-phase thyristor rectifier bridge 6 connected to the secondary winding of the balancing reactor 5 with a secondary side, thyristors T2 and T3 are in a reverse blocking state, and no current flows through it, and thyristors T1 and T4 are in a forward conduction state, and current flows through it. The auxiliary single-phase thyristor rectifier bridge 6 and the first nine-phase half-wave thyristor bridge 3 jointly supply power to the electrolytic cell 7.

[0078] Principle analysis: ​

[0079] The 36-pulse hydrogen production converter based on a controllable pulse multiplication balancing reactor described in this invention utilizes a pulse multiplication circuit constructed on the DC side of a parallel 18-pulse thyristor rectifier to modulate the output current of the first nine-phase half-wave thyristor bridge 3 and the second nine-phase half-wave thyristor bridge 4. By adjusting the turns ratio of the primary and secondary windings of the balancing reactor 5 with a secondary side, the output currents of the first nine-phase half-wave thyristor bridge 3 and the second nine-phase half-wave thyristor bridge 4 are both three-level stepped DC currents. Based on the relationship between the AC and DC voltages and currents of the 18-pulse rectifier, the pulse count is doubled, from 18 to 36 pulses. This effectively suppresses the input current harmonics and output voltage ripple of the 36-pulse rectifier without substantially increasing the rectifier's complexity.

[0080] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A 36-pulse hydrogen production converter based on a controllable pulse multiplication balancing reactor, comprising a first nine-phase phase-shifting transformer (1), a second nine-phase phase-shifting transformer (2), a first nine-phase half-wave thyristor bridge (3), and a second nine-phase half-wave thyristor bridge (4); the first nine-phase phase-shifting transformer (1) and the second nine-phase phase-shifting transformer (2) are used to shift the phase of the three-phase voltage output by the power grid to generate two groups of nine-phase voltages with the same amplitude and a phase difference of 20°, and the two groups of nine-phase voltages are respectively input to the first nine-phase half-wave thyristor bridge (3) and the second nine-phase half-wave thyristor bridge (4) for rectification; characterized in that The 36-pulse hydrogen converter also includes an inductor L s , a trigger signal generator (8) and a controllable pulse wave multiplication balancing reactor; The controllable pulse multiplication balancing reactor is used to multiply the number of pulses of the three-phase current output by the power grid from 18 pulses to 36 pulses, and the controllable pulse multiplication balancing reactor includes a balancing reactor with a secondary side (5) and an auxiliary single-phase thyristor rectifier bridge (6), and the primary and secondary winding turns ratio of the balancing reactor with a secondary side (5) is 33; The positive polarity output ends of the first nine-phase half-wave thyristor bridge (3) and the second nine-phase half-wave thyristor bridge (4) are respectively connected to the same-name end and the opposite-name end of the primary winding of the balancing inductor (5) with a secondary side; The central output of the primary winding of the balancing reactor (5) with the secondary side is connected to the DC output end of the auxiliary single-phase thyristor rectifier bridge (6) and the inductor L s The same-name end and the opposite-name end of the secondary winding of the balancing reactor (5) with the secondary side are respectively connected to the first and second AC input ends of the auxiliary single-phase thyristor rectifier bridge (6), the DC input end of the auxiliary single-phase thyristor rectifier bridge (6) is simultaneously connected to the neutral point of the first nine-phase phase-shifting transformer (1) and the second nine-phase phase-shifting transformer (2), and the negative pole of the electrolytic cell (7), and the positive pole of the electrolytic cell (7) is connected to the inductor L s The other end of the connection; The trigger signal generator (8) is used to perform zero-crossing detection on the phase of the A-phase voltage in the three-phase voltage output by the power grid, and when the phase of the A-phase voltage is 0 during the process of changing from negative to positive, three sets of trigger signals are generated to respectively control the thyristor control terminals of the first nine-phase half-wave thyristor bridge (3), the second nine-phase half-wave thyristor bridge (4) and the auxiliary single-phase thyristor rectifier bridge (6).

2. The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to claim 1 is characterized in that: A first group of trigger signals for controlling the first nine-phase half-wave thyristor bridge (3) includes nine trigger signals, and the nine trigger signals respectively control the nine thyristors of the first nine-phase half-wave thyristor bridge (3); There is a one-to-one correspondence between the nine thyristors of the first nine-phase half-wave thyristor bridge (3) and the nine-phase voltage outputted by it, and the conduction angle of the thyristor corresponding to the first phase voltage outputted by the first nine-phase half-wave thyristor bridge (3) is α, and the phase angle of the trigger signal of the thyristor corresponding to the first phase voltage is obtained by shifting the phase by α when the phase of the A phase voltage in the three-phase voltage outputted by the power grid changes from negative to positive and the phase is 0; The phase angles of the trigger signals of the nine thyristors corresponding to the nine-phase voltage output by the first nine-phase half-wave thyristor bridge (3) increase sequentially from the first phase to the ninth phase, and the phase angles of the trigger signals of the two thyristors corresponding to the two adjacent phase voltages differ by 40 degrees; A set of trigger signals for controlling the second nine-phase half-wave thyristor bridge (4) includes nine trigger signals, and the nine trigger signals respectively control the nine thyristors of the second nine-phase half-wave thyristor bridge (4); The phase angle of the trigger signal of the thyristor corresponding to each phase voltage in the second nine-phase half-wave thyristor bridge (4) differs by 20° from the phase angle of the trigger signal of the thyristor corresponding to the corresponding phase voltage in the first nine-phase half-wave thyristor bridge (3), and the phase angle of the trigger signal of the thyristor in the second nine-phase half-wave thyristor bridge (4) corresponding to the same-phase voltage is greater than the phase angle of the trigger signal of the thyristor in the first nine-phase half-wave thyristor bridge (3); A set of trigger signals for controlling the auxiliary single-phase thyristor rectifier bridge (6) includes four trigger signals, and the four trigger signals respectively control the four thyristors of the auxiliary single-phase thyristor rectifier bridge (6), the four thyristors are diagonally conductive, and the trigger signals received by the two thyristors located at the diagonals are the same; The phase angle of the trigger signal received by the thyristor in the upper bridge arm of the same bridge arm in the auxiliary single-phase thyristor rectifier bridge (6) is β1, and β1=α+10°, and the phase angle of the trigger signal received by the thyristor in the lower bridge arm of the same bridge arm is β2, and β2=α+30°.

3. The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to claim 2 is characterized in that: The voltage with the smallest phase output by the first nine-phase half-wave thyristor bridge (3) serves as the first phase voltage output by the first nine-phase half-wave thyristor bridge (3).

4. The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to claim 2 is characterized in that: The conduction period of the thyristors in the auxiliary single-phase thyristor rectifier bridge (6) is 1 / 9 of the conduction period of the thyristors in the first nine-phase half-wave thyristor bridge (3).

5. The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to claim 1 is characterized in that: The turns ratio of the primary and secondary windings of the balancing inductor (5) with a secondary side is 33.

6. The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to claim 1 is characterized in that: The auxiliary single-phase thyristor rectifier bridge (6) includes a thyristor T1, a thyristor T2, a thyristor T3 and a thyristor T4; After the anode of the thyristor T1 is connected to the cathode of the thyristor T3, it serves as the first AC input terminal of the auxiliary single-phase thyristor rectifier bridge (6); After the anode of the thyristor T2 is connected to the cathode of the thyristor T4, it serves as the second AC input terminal of the auxiliary single-phase thyristor rectifier bridge (6); After the cathode of the thyristor T1 is connected to the cathode of the thyristor T2, it serves as the DC output end of the auxiliary single-phase thyristor rectifier bridge (6); After the anode of the thyristor T3 is connected to the anode of the thyristor T4, it serves as the DC input terminal of the auxiliary single-phase thyristor rectifier bridge (6).

7. The 36-pulse hydrogen production converter based on a controllable pulse multiplication and balancing reactor according to claim 6 is characterized in that: The voltage across the secondary winding of the balancing reactor (5) with a secondary side is u s , the voltage across the electrolytic cell (7) is u d The controllable pulse multiplication balancing reactor includes three working modes, specifically: Working mode Ⅰ: When -u s >u d When the thyristors in the first nine-phase half-wave thyristor bridge (3) connected to the same-name end of the primary winding of the balancing reactor (5) with the secondary side are in a reverse blocking state, and no current flows; the second nine-phase half-wave thyristor bridge (4) connected to the opposite-name end of the primary winding of the balancing reactor (5) with the secondary side is in a forward conduction state, and current flows; at the same time, in the auxiliary single-phase thyristor rectifier bridge (6) connected to the secondary winding of the balancing reactor (5) with the secondary side, thyristors T1 and T4 are in a reverse blocking state, and no current flows, while thyristors T2 and T3 are in a forward conduction state, and current flows, and the auxiliary single-phase thyristor rectifier bridge (6) and the second nine-phase half-wave thyristor bridge (4) jointly supply power to the electrolytic cell (7); Working mode II: When |u s | d When the first nine-phase half-wave thyristor bridge (3) connected to the same-name end of the primary winding of the balancing reactor (5) with the secondary side and the second nine-phase half-wave thyristor bridge (4) connected to the opposite-name end of the primary winding of the balancing reactor (5) with the secondary side are both in a forward conduction state, with current flowing through them. At the same time, the thyristors T1 to T4 in the auxiliary single-phase thyristor rectifier bridge (6) connected to the secondary winding of the balancing reactor (5) with the secondary side are in a reverse blocking state, with no current flowing through them. The first nine-phase half-wave thyristor bridge (3) and the second nine-phase half-wave thyristor bridge (4) jointly supply power to the electrolytic cell (7);​ Working mode III: When u s >u d When the first nine-phase half-wave thyristor bridge (3) connected to the same-name end of the primary winding of the balancing reactor (5) with the secondary side is in a forward conduction state, with current flowing through it; the second nine-phase half-wave thyristor bridge (4) connected to the opposite-name end of the primary winding of the balancing reactor (5) with the secondary side is in a reverse blocking state, with no current flowing through it; at the same time, in the auxiliary single-phase thyristor rectifier bridge (6) connected to the secondary winding of the balancing reactor (5) with the secondary side, thyristors T2 and T3 are in a reverse blocking state, with no current flowing through it, and thyristors T1 and T4 are in a forward conduction state, with current flowing through it, and the auxiliary single-phase thyristor rectifier bridge (6) and the first nine-phase half-wave thyristor bridge (3) jointly supply power to the electrolytic cell (7).

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