光伏-PEM制氢系统建模及不同耦合方式性能对比分析

Modeling of photovoltaic-PEM hydrogen production system and comparative performance analysis of different coupling methods

光伏耦合电解槽制氢是生产氢气的主要方式,但是光伏电池输出功率会因为太阳辐照度的波动而变化,并存在间歇性发电的问题。为提高太阳能的利用率及光伏制氢系统的稳定性,建立了由光伏电池和质子交换膜(PEM)电解槽组成的间接耦合制氢系统。系统由光伏电池、PEM电解槽、最大功率点跟踪(MPPT)控制器、直流-直流(DC-DC)转换器和蓄电池组成。该系统通过蓄电池对光伏电池产生的电能进行调控,在太阳辐照度较高时储存多余电量,在光伏电池发电量不足的情况下为电解槽供电。通过仿真验证了该系统的有效性,并对比了使用不同耦合方式的光伏制氢系统的效率和产氢速率。结果表明,间接耦合系统的总效率在所用耦合系统中最高,产氢速率不随太阳辐照度的变化而改变;优化耦合系统的产氢速率最高,但是电解槽的电解效率随太阳辐照度的增大而减小;直接耦合系统由于光伏电池与电解槽尺寸不匹配的问题,导致系统总效率和产氢速率极低。

Hydrogen production by photovoltaic-coupled electrolyzers is the main way to produce hydrogen,but outputs of photovoltaic cells vary with fluctuations of solar radiation,which will lead to intermittent power generation.In order to improve the utilization of solar energy as well as the stability of the photovoltaic hydrogen production system,an indirectly coupled hydrogen production system consisting of a photovoltaic cell and a proton exchange membrane(PEM)electrolyzer is established.The system consists of photovoltaic cells,a PEM electrolyzer,a maximum power point tracking(MPPT)controller,a DC-DC converter and a battery.The system regulates the electrical energy generated by PV cells by controlling the battery which stores excess power when the intensity of solar radiation is high and drives the electrolyzer when the PV cells cannot generate sufficient power.The effectiveness of the system is verified by a simulation test.The energy efficiencies and hydrogen production rates of PV hydrogen production systems using different coupling methods are compared.The results show that,among all the coupled systems proposed,the comprehensive efficiency of the indirect coupled system is the highest,and its hydrogen production rate does not change with the intensity of solar radiation.The optimized coupled system has the highest hydrogen production rate,but its electrolysis efficiency decreases with the increase of solar radiation intensity.The direct-coupled system has a quite low comprehensive efficiency and hydrogen production rate due to the mismatch between the PV cell and electrolyzer sizes.