Electrolytic hydrogen production hybrid rectifier control system for fluctuating power input

Abstract

The invention discloses an electrolytic hydrogen production hybrid rectifier control system for fluctuating power input, and the system comprises a three-phase multi-winding transformer which is used for achieving the transformation of voltage and supplying power through a network side; the output end of the thyristor rectifier is connected with the electrolytic bath and used for supplying power to the electrolytic bath; the output end of the IGBT rectifier is connected with the electrolytic bath, and the IGBT rectifier is used for supplying power to the electrolytic bath; and the controller is used for adjusting the running state of the three-phase multi-winding transformer and the running power of the thyristor rectifier and the IGBT rectifier according to a two-stage power fluctuation range by receiving a power instruction sent by the energy management system. Through innovative circuit design and control strategies, accurate control over the electrolytic hydrogen production process is achieved, the hydrogen production efficiency is improved, the cost is reduced, and harmonic pollution to a power grid is reduced. The hybrid rectifier can better adapt to the volatility of renewable energy power generation, and an efficient, stable and economical solution is provided for the field of electrolytic hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of electrolytic hydrogen production technology, and more particularly to a control system for an electrolytic hydrogen production hybrid rectifier for fluctuating power input. Background Technology

[0002] With the transformation of the global energy structure and the increasing emphasis on renewable energy, hydrogen energy, as a clean and efficient energy carrier, has received widespread attention for its development and utilization. Electrolysis of water to produce hydrogen has become an important pathway and transformation direction for hydrogen energy production due to its ability to deeply couple with renewable energy, effectively absorb renewable energy, reduce the impact of renewable energy on the power system, and achieve zero carbon emissions. In electrolysis hydrogen production systems, the performance of the rectifier has a decisive impact on the efficiency and stability of the system.

[0003] Existing electrolytic hydrogen production rectifiers mainly include thyristor rectifiers and IGBT rectifiers. Thyristor rectifiers are widely used due to their simple structure and low cost, but they cause significant harmonic pollution to the power grid. They typically employ multiple parallel outputs, using a front-stage transformer for phase-shifting rectification, thus forming a multi-pulse rectification system. The front-stage transformer is generally equipped with an on-load tap changer, adjusting the rectifier's output power by regulating the thyristor rectifier's firing angle and the tap changer's position. However, firstly, most on-load tap changers are mechanical, making them difficult to adapt to the volatility of renewable energy sources; secondly, the lifespan of on-load tap changers is usually limited, and frequent adjustments lead to increased maintenance costs. While IGBT rectifiers offer high control precision and low harmonic pollution, their cost is high, and they face certain limitations in high-power applications.

[0004] To address the shortcomings of existing technologies, this invention provides a novel hybrid rectifier for electrolytic hydrogen production. This rectifier combines the characteristics of thyristor rectifiers and IGBT rectifiers with the respective working principles and features of the on-load tap changer on the secondary side of the upstream transformer. Through a controller, it effectively and stably absorbs fluctuating input power while also considering the later maintenance costs of each component. The hybrid rectifier of this invention can automatically adjust the operating status of the transformer and the operating power of the thyristor rectifier and IGBT rectifier according to power commands issued by the energy management system to adapt to different power fluctuation ranges, thereby improving the stability and efficiency of the electrolytic hydrogen production system. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a hybrid rectifier control system for electrolytic hydrogen production with fluctuating power input. Through innovative circuit design and control strategies, it achieves precise control of the electrolytic hydrogen production process, improving hydrogen production efficiency, reducing costs, and minimizing harmonic pollution to the power grid. The hybrid rectifier of this invention can better adapt to the volatility of renewable energy power generation, providing an efficient, stable, and economical solution for the electrolytic hydrogen production field.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A control system for an electrolytic hydrogen production hybrid rectifier with fluctuating power input, comprising:

[0008] Three-phase multi-winding transformers are used to transform voltage and supply power through the grid side;

[0009] The thyristor rectifier has its output terminal connected to the electrolytic cell to supply power to the electrolytic cell;

[0010] The IGBT rectifier is connected to the electrolytic cell at its output end and is used to supply power to the electrolytic cell.

[0011] The controller, by receiving power commands from the energy management system, adjusts the operating status of the three-phase multi-winding transformer and the operating power of the thyristor rectifier and IGBT rectifier according to the two-level power fluctuation range.

[0012] Preferably, the three-phase multi-winding transformer has one primary winding and at least four secondary windings, wherein at least three secondary windings are equipped with on-load tap changers and at least one secondary winding is not equipped with an on-load tap changer.

[0013] The secondary windings equipped with on-load tap changers are moved relative to each other by a certain phase angle to form a phase difference.

[0014] Preferably, the three-phase multi-winding transformer is equipped with a load tap changer, and the output terminals of the secondary windings are respectively connected to the input terminals of the thyristor rectifiers.

[0015] Preferably, the fixing mechanism includes a fixing spring installed on the outer wall of the positioning pin, and the two ends of the fixing spring are elastically connected to the outer wall of the support plate and the inner wall of the lever, respectively.

[0016] Preferably, the output terminal of the secondary winding of the three-phase multi-winding transformer without a load tap changer is connected to the input terminal of the IGBT rectifier, and the output terminal of the IGBT is connected to the electrolytic cell to supply power to the electrolytic cell.

[0017] This invention achieves precise control of the electrolytic hydrogen production process through innovative circuit design and control strategies, improving hydrogen production efficiency, reducing costs, and minimizing harmonic pollution to the power grid. The hybrid rectifier of this invention can better adapt to the volatility of renewable energy power generation, providing an efficient, stable, and economical solution for the electrolytic hydrogen production field. Attached Figure Description

[0018] Figure 1 This is a circuit topology block diagram of the electrolytic hydrogen production hybrid rectifier according to an embodiment of the present invention.

[0019] Figure 2 This is a circuit topology block diagram of a thyristor rectifier according to an embodiment of the present invention.

[0020] Figure 3 This is a circuit topology block diagram of an IGBT rectifier according to an embodiment of the present invention.

[0021] Figure 4 This is a control block diagram of a thyristor rectifier according to an embodiment of the present invention.

[0022] Figure 5 This is a control block diagram of the IGBT rectifier according to an embodiment of the present invention.

[0023] Figure 6 This is a control flowchart of the electrolytic hydrogen production hybrid rectifier according to an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] See Figure 1-6 This embodiment provides a hybrid rectifier control system for electrolytic hydrogen production with fluctuating power input, including: a three-phase multi-winding transformer, a thyristor rectifier, and an IGBT rectifier; the thyristor rectifier is a 6-pulse thyristor rectifier, such as... Figure 2 As shown; the IGBT rectifier is a three-phase full-bridge IGBT rectifier, as follows. Figure 3 As shown;

[0026] A three-phase multi-winding transformer has one primary winding and four secondary windings. The first three secondary windings are equipped with on-load tap changers, while the fourth secondary winding is not equipped with an on-load tap changer. The secondary windings equipped with on-load tap changers are shifted relative to each other by a certain phase angle to form a multi-pulse rectifier on the DC side in conjunction with a thyristor rectifier.

[0027] The output terminals of the secondary windings of the three-phase multi-winding transformer equipped with a load tap changer are connected to the input terminals of the thyristor rectifier.

[0028] The input terminal of a thyristor rectifier is connected in parallel with the output terminal of the secondary winding of a three-phase multi-winding transformer equipped with an on-load tap changer to form a multi-pulse rectifier for powering the electrolytic cell. Figure 1 As shown.

[0029] The thyristor rectifier uses a phase-locked loop to calculate the AC side phase as the reference for the trigger pulse. The difference between the power command from the energy management system and the actual power flowing through the DC side is used as the input to the PID controller. The PID controller controls the trigger angle of each group of thyristor rectifiers. The specific control block diagram is shown below. Figure 4 As shown.

[0030] The IGBT rectifier adopts a dual closed-loop control strategy based on dq decoupling, consisting of a power outer loop and a current inner loop. The specific control steps are as follows:

[0031] Voltage and current on the grid side are collected using voltage transformers and current transformers;

[0032] The grid-side phase is obtained through a phase-locked loop, and the collected real-time grid-side voltage and current are transformed using coordinate transformation to obtain Id, Iq, Ed, and Eq.

[0033] The real-time DC output power P is acquired by a sensor. P is compared with the power command value P_ref and then sent to the PID controller to generate Id_ref. The real-time value Id is compared with the command value Id_ref and then sent to the PID controller. The signal generated by the PID controller is integrated with Iq and Ed to generate Ed_ref. Iq_ref is compared with the real-time value Iq and then sent to the PID controller. The signal generated by the PID controller is integrated with Id and Eq to generate Eq_ref. The coordinate transformation is used to convert Ed_ref and Eq_ref into three-phase voltage command values ​​Va_ref, Vb_ref, and Vc_ref.

[0034] The SVPWM modulation module generates six PWM signals to control the six switching transistors of the IGBT rectifier. The specific control block diagram is as follows: Figure 5 As shown.

[0035] The output terminal of the secondary winding of the three-phase multi-winding transformer without a load tap changer is connected to the input terminal of the IGBT rectifier, and the output terminal of the IGBT is connected to the electrolytic cell to supply power to the electrolytic cell.

[0036] According to the two-level power fluctuation range, it refers to:

[0037] The primary and secondary power fluctuation ranges are set in advance, with the secondary power fluctuation range being larger than the primary power fluctuation range. The size of each power fluctuation range is set according to the power range that can be adjusted sequentially by adjusting the IGBT rectifier, thyristor rectifier, and on-load tap changer.

[0038] By receiving power commands from the energy management system and adjusting the operating status of the three-phase multi-winding transformer, as well as the operating power of the thyristor rectifier and IGBT rectifier, according to the two-level power fluctuation range, it means:

[0039] When the change in the operating power (i.e. input power) command of the hybrid rectifier issued by the energy management system is less than the fluctuation within the first-level power fluctuation range, the power change is met only by adjusting the operating power of the IGBT rectifier, thereby maintaining the system power balance.

[0040] By receiving power commands from the energy management system and adjusting the operating status of the three-phase multi-winding transformer, as well as the operating power of the thyristor rectifier and IGBT rectifier, according to the two-level power fluctuation range, it means:

[0041] When the change in the operating power (i.e. input power) command of the hybrid rectifier issued by the energy management system is greater than the fluctuation range of the first-level power fluctuation but less than the fluctuation range of the second-level power fluctuation, the operating power is adjusted by adjusting the firing angle of the thyristor rectifier to meet the power change and maintain the power balance of the system. At this time, the operating power of the IGBT rectifier needs to be re-determined.

[0042] By receiving power commands from the energy management system and adjusting the operating status of the three-phase multi-winding transformer, as well as the operating power of the thyristor rectifier and IGBT rectifier, according to the two-level power fluctuation range, it means:

[0043] When the change in the operating power (i.e. input power) command of the hybrid rectifier issued by the energy management system exceeds the secondary power fluctuation range, the on-load tap changer position of the first three secondary windings of the three-phase multi-winding transformer is adjusted to meet the power change and maintain the system power balance. At this time, it is necessary to redetermine the firing angle of the thyristor rectifier and the operating power of the IGBT rectifier.

[0044] The control flowchart for adjusting the operating status of the three-phase multi-winding transformer, the thyristor rectifier, and the IGBT rectifier by receiving power commands from the energy management system and according to the two-level power fluctuation range is as follows: Figure 6 As shown.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A control system for an electrolytic hydrogen production hybrid rectifier with fluctuating power input, characterized in that, include: Three-phase multi-winding transformers are used to transform voltage and supply power through the grid side; The thyristor rectifier has its output terminal connected to the electrolytic cell to supply power to the electrolytic cell; The IGBT rectifier is connected to the electrolytic cell at its output end and is used to supply power to the electrolytic cell. The controller, by receiving power commands from the energy management system, adjusts the operating status of the three-phase multi-winding transformer and the operating power of the thyristor rectifier and IGBT rectifier according to the two-level power fluctuation range.

2. The control system for an electrolytic hydrogen production hybrid rectifier with fluctuating power input according to claim 1, characterized in that, The three-phase multi-winding transformer has one primary winding and at least four secondary windings, wherein at least three secondary windings are equipped with on-load tap changers and at least one secondary winding is not equipped with an on-load tap changer. The secondary windings equipped with on-load tap changers are moved relative to each other by a certain phase angle to form a phase difference.

3. A control system for an electrolytic hydrogen production hybrid rectifier with fluctuating power input according to claim 1, characterized in that, The three-phase multi-winding transformer is equipped with a load tap changer, and the output terminals of the secondary windings are connected to the input terminals of the thyristor rectifiers.

4. A control system for an electrolytic hydrogen production hybrid rectifier with fluctuating power input according to claim 3, characterized in that, The input terminal of the thyristor rectifier is connected to the output terminal of the secondary winding of the three-phase multi-winding transformer equipped with a load tap changer, and is connected in parallel with the output terminal of the thyristor rectifier to output the phase difference to form a multi-pulse rectifier to supply power to the electrolytic cell.

5. A control system for an electrolytic hydrogen production hybrid rectifier with fluctuating power input according to claim 4, characterized in that, The output terminal of the secondary winding of the three-phase multi-winding transformer without a load tap changer is connected to the input terminal of the IGBT rectifier, and the output terminal of the IGBT is connected to the electrolytic cell to supply power to the electrolytic cell.

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