CN-122026440-A - High-integration integrated hydrogen production power generation system and control method thereof

CN122026440ACN 122026440 ACN122026440 ACN 122026440ACN-122026440-A

Abstract

The invention discloses a high-integration integrated hydrogen production power generation system and a control method thereof, wherein the system comprises a T-shaped three-level rectifying/inverter and a multiphase multiple bidirectional buck-boost converter as a core power processing unit, the switch is used for carrying out hardware multiplexing between the hydrogen making mode and the power generation mode. In the hydrogen production mode, the system performs current closed-loop control on the electrolytic tank, and improves the overall efficiency of the system through optimal current distribution among the phase converters. In the power generation mode, the system performs voltage closed-loop control on the direct-current bus, and adopts a double-loop control structure of a bus voltage outer loop and an inductance current inner loop so as to maintain the bus voltage stable. The system realizes the integration of hydrogen production and power generation functions through hardware multiplexing, mode control and current distribution optimization. The bidirectional buck-boost converter provides core hardware support for bidirectional energy flow and wide voltage adaptation by virtue of the symmetrical circuit topology and the automatic mode switching capability based on hysteresis comparison.

Inventors

SHEN YONGPENG
ZHAO CHEN
ZHANG QIUKUI
YANG XIAOLIANG
GUO LEILEI
ZHAO JIANGHAN
LI LINJIE
WANG SHIQIAN
GAO JINWU
ZHANG YIHAN
Zhang Yegui
YUAN XIAOFANG
ZHANG ZHENYA
LIU PU
CAO MINGHAO

Assignees

郑州轻工业大学

Dates

Publication Date: 20260512
Application Date: 20260113

Claims (10)

1. The high-integration integrated hydrogen production power generation system is characterized by comprising a power conversion unit, a switching unit, a hydrogen production unit and a power generation unit; The power conversion unit comprises a three-level rectifying/inverter and a multiphase multiple bidirectional buck-boost converter, the three-level rectifying/inverter is connected with a power grid, and the multiphase multiple bidirectional buck-boost converter is connected between the three-level rectifying/inverter and the switching unit; the switching unit is used for selectively conducting the electrical connection between the multiphase multiple bidirectional buck-boost converter and the hydrogen production unit or between the multiphase multiple bidirectional buck-boost converter and the power generation unit; in the hydrogen production mode, the three-level rectification/inverter converts the power grid alternating current into direct current, and the multiphase multiple bidirectional buck-boost converter converts the direct current into direct current suitable for preparing hydrogen units; In the power generation mode, the multiphase multiple bidirectional buck-boost converter converts the direct current output by the power generation unit into direct current which is adaptive to the three-level rectifying/inverting device, and the three-level rectifying/inverting device inverts the direct current into alternating current and feeds the alternating current into a power grid.
2. The high-integration integrated hydrogen production power generation system according to claim 1, wherein the multiphase multiple bidirectional buck-boost converter is formed by connecting at least two bidirectional buck-boost converters in parallel, the bidirectional buck-boost converters adopt a bilateral circuit topology, hydrogen production current detection resistors are arranged on the right sides of the bidirectional buck-boost converters, and inductance current detection resistors in a boost mode and a buck mode are respectively arranged on the left sides and the right sides of the bidirectional buck-boost converters.
3. The high integration integrated hydrogen production power generation system of claim 1, wherein the switching unit comprises a first switch group and a second switch group; The first switch group is used for controlling the on-off of the multiphase multiple bidirectional buck-boost converter and the hydrogen production unit, and the second switch group is used for controlling the on-off of the multiphase multiple bidirectional buck-boost converter and the power generation unit; in the hydrogen production mode, the first switch group is closed, and the second switch group is opened; In the power generation mode, the second switch group is closed, and the first switch group is opened.
4. The high integration integrated hydrogen production power generation system of claim 1, wherein the initial phase difference of each phase of the multi-phase multi-bi-directional buck-boost converter is 2 pi/N, where N is the total number of phases of the multi-phase multi-bi-directional buck-boost converter.
5. The high integration integrated hydrogen production power generation system of claim 1 further comprising a boost converter connected between the three-level rectifier/inverter and a power grid for voltage level conversion and electrical isolation.
6. The high integration integrated hydrogen production power generation system of claim 1, wherein the hydrogen production unit is an alkaline electrolyzer, a PEM electrolyzer or a solid oxide electrolyzer, the power generation unit is a proton exchange membrane fuel cell, and the three-level rectifier/inverter is a T-type three-level rectifier inverter comprising a fully controlled switching device.
7. The high-integration integrated hydrogen production and power generation control method is applied to the high-integration integrated hydrogen production and power generation system as claimed in any one of claims 1 to 6, and is characterized by comprising the steps of selectively conducting the electrical connection of the multiphase multiple bidirectional buck-boost converter and the hydrogen production unit or the multiphase multiple bidirectional buck-boost converter and the power generation unit through the switching unit to realize the switching between a hydrogen production mode and a power generation mode; in the hydrogen production mode, controlling a three-level rectifying/inverting device to rectify the power grid alternating current into direct current, controlling a multiphase multiple bidirectional buck-boost converter to work in a current closed-loop control mode, and converting the direct current into direct current suitable for preparing hydrogen units; In the power generation mode, the multiphase multiple bidirectional buck-boost converter is controlled to work in a voltage closed-loop control mode, direct current output by the power generation unit is converted into direct current which is adaptive to the three-level rectifying/inverting device, and the three-level rectifying/inverting device is controlled to invert the direct current into alternating current and feed the alternating current into a power grid.
8. The high integration integrated hydrogen production and power generation control method according to claim 7, further comprising the step of optimally distributing multiphase output current based on efficiency characteristics of each phase bidirectional buck-boost converter: a) Offline testing an efficiency model of each phase converter under different bus voltages and different output currents; b) Constructing an optimization objective function comprising an electrolytic cell current density-voltage function, the number of electrolytic cells and each phase efficiency model, and solving to obtain an optimal input phase number and each phase working current; c) The constraint of the optimization objective function is that the sum of the phase currents is equal to the total electrolysis current and that each phase current is between its minimum output current and maximum output current.
9. The high integration integrated hydrogen production and power generation control method of claim 7, wherein the voltage closed loop control comprises bus voltage PI control and inductor current PI control: a) The deviation between the given value and the actual value of the bus voltage is taken as input, and the target current of the fuel cell is output through PI control; b) The deviation between the target value of each phase current and the detection value of the inductance current is taken as input, and the duty ratio signal is output through PI control to adjust the working state of the converter.
10. The high-integration integrated hydrogen production power generation control method according to claim 1, wherein the multiphase multiple bidirectional buck-boost converter realizes automatic switching of a buck mode and a boost mode through a hysteresis comparison method: a) In the hydrogen production mode, the left side voltage and the right side voltage of the converter are compared in real time, the converter is switched to a step-down mode when the left side voltage is larger than the sum of the right side voltage and the threshold value, and the converter is switched to a step-up mode when the left side voltage is smaller than the difference between the right side voltage and the threshold value; b) In the power generation mode, the right side voltage and the left side voltage of the converter are compared in real time, the voltage is switched to a step-down mode when the right side voltage is larger than the sum of the left side voltage and the threshold value, the voltage is switched to a step-up mode when the right side voltage is smaller than the difference between the left side voltage and the threshold value, and the working mode at the last moment is kept when the voltage is in the threshold value interval.

Description

High-integration integrated hydrogen production power generation system and control method thereof Technical Field The invention relates to the technical field of hydrogen energy and new energy power generation control, in particular to a high-integration integrated hydrogen production power generation system and a control method thereof. Background The hydrogen electric coupling is used for constructing a high-efficiency flexible energy system through mutual conversion and cooperation of electric power and hydrogen energy, the core approach is that the redundant renewable electric power is utilized to electrolyze water to prepare green hydrogen, then the green hydrogen is generated by a fuel cell to feed back to a power grid, the adjustment and distribution of energy in time and space are realized, finally, an electric-hydrogen-electric clean energy closed loop is formed, and the method has important significance for solving the problems of intermittence and fluctuation of renewable energy and enhancing the toughness of the power grid. The conventional electrical hydrogen coupling system has the remarkable defects that: a) The system has a complex structure, an AC/DC rectifying circuit, a DC/DC current source and a DC/DC voltage source and a DC/AC inverter are needed in the hydrogen production link, four independent power circuits are involved in the power generation link, and the redundancy of devices is high; b) The circuit multiplexing rate is low, namely, the hydrogen production of the electrolytic cell and the power generation of the fuel cell do not work simultaneously, so that each power circuit is idle in a time-sharing way and hardware multiplexing cannot be realized; c) The energy conversion efficiency is low, the electric energy needs to be converted for a plurality of times (such as alternating current-direct current-alternating current), each conversion generates energy loss, and the overall efficiency is limited. The prior similar technology comprises a CN202410475066.X new energy hydrogen production power supply, a system and a control method thereof, a hydrogen production power supply circuit based on primary high-frequency conversion of CN202411135906.4, a hydrogen production power supply system and a control method thereof of CN202510365439.2, a CN202510494745.6 hydrogen production power supply system and a control method thereof, a CN202310790842.0 hydrogen production device and a fuel cell coupled hydrogen production power generation system. The above technologies do not solve the core problems of power hardware multiplexing, wide voltage adaptation and accurate control of the sub-modes, and are difficult to consider both the system integration level and the energy conversion efficiency. Therefore, a high-integration integrated hydrogen production power generation system and a control method thereof are needed. Disclosure of Invention The invention aims to provide a high-integration integrated hydrogen production power generation system and a control method thereof, which are used for solving the defects of complex system structure, low circuit multiplexing rate and low energy conversion efficiency in the prior art. The technical scheme for solving the technical problems is as follows: The high-integration integrated hydrogen production power generation system comprises a power conversion unit, a switching unit, a hydrogen production unit, a power generation unit, a boost converter and a control unit, wherein the connection relation and the functions of all the components are as follows: a) The power conversion unit comprises a T-shaped three-level rectifying inverter and a multiphase multiple bidirectional buck-boost converter, wherein the T-shaped three-level rectifying inverter is composed of 24 fully-controlled switching devices (such as reverse conducting IGBT (insulated gate bipolar transistor) and MOSFET (metal oxide semiconductor field effect transistor)), has two working modes of rectification and inversion, the input end of the T-shaped three-level rectifying inverter is connected with a power grid through a boost transformer, the output end of the T-shaped three-level rectifying inverter is connected with the left side of the multiphase multiple bidirectional buck-boost converter, the multiphase multiple bidirectional buck-boost converter is composed of at least two bidirectional buck-boost converters in parallel (three-phase triplex in the embodiment), a bilateral symmetry topological structure is adopted, and hydrogen production current detection resistors are arranged on the right side of the T-shaped three-level rectifying inverter The left side and the right side are respectively provided with a boost-buck mode inductance current detection resistor、The device is used for realizing bidirectional energy transmission and buck-boost conversion; b) The switching unit comprises a first switch group /) And a second switch group/) Is used for controlling the on-off of the multip