Abstract:

During the process of switching from grid connected to off grid of green power hydrogen production, the imbalance of active and reactive power causes frequency and voltage oscillations of the microgrid, and the inverter is overloaded and out of operation. In order to solve these problems, a multi-mode control strategy for energy storage is proposed with the goal of stable operation during hydrogen production grid connected and off grid switching. Firstly, establish the power conversion equation for the energy storage system and analyze the power and frequency regulation relationship of the energy storage controller. Secondly, study the multi-mode switching strategy for energy storage, analyze the key factors for stable off grid switching, and compare the impact of energy storage capacity and controller parameters on the system. Finally, taking a typical green power hydrogen production microgrid as an example, the switching performance under different energy storage capacities and adjustment coefficients is simulated and calculated. The results indicate that the higher the proportion of energy storage capacity, the less apparent power overshoot of energy storage, and the lower the risk of equipment overload. Under the same energy storage capacity, the smaller the adjustment coefficient, the smaller the peak apparent power, and the lower the risk of overload. However, at the same time, it is required that the current overload capacity of the inverter is strong. The adjustment coefficient of 0.20 can meet various operating conditions of grid connection and off grid.

Key words: green power hydrogen production unit, grid connected, off grid, power supply stability, energy storage system, adjustment coefficient, microgrid frequency, apparent power

摘要：

针对绿电制氢装置并网向离网切换的过程中，有功功率和无功功率不平衡引起的微电网频率、电压振荡以及变流器过载退出运行等问题，以制氢并离网切换稳定运行为目标，提出储能多模式控制策略。首先，建立储能系统功率转换方程，分析储能控制器功率、频率调节关系；其次，研究储能多模式切换策略，分析离网切换稳定关键因素，比较储能容量、控制器参数对系统影响；最后，以典型绿电制氢微电网为例，仿真计算不同储能容量及调差系数下的切换性能。结果表明：储能容量占比越高，储能视在功率超调越少，设备过载风险越小；同样储能容量下，调差系数越小，视在功率峰值越小，过载风险越低，但同时要求变流器电流过载能力强；调差系数取0.20时，可满足并网、离网中多种运行工况。

关键词: 绿电制氢装置, 并网, 离网, 供电稳定性, 储能系统, 调差系数, 微电网频率, 视在功率