【作者】 王娟；

【导师】 李鑫；

【作者基本信息】 合肥工业大学 ， 控制科学与工程， 2021， 硕士

【摘要】 大力发展光伏(Photovoltaic,PV)发电可以缓解我国目前面临的能源短缺、电力供应不足以及环境污染等问题,独立光储系统不依赖电网运行,在无电或频繁停电的场所得到了广泛应用。在光储系统运行过程中应保证瞬时功率平衡、系统稳定、安全运行,因此如何有效地解决光储系统功率分配和能量管理控制问题依然迫在眉睫。本研究选择将超级电容(Super Capacitor,SC)与全钒液流电池(Vanadium Redox Batteries,VRB)构成混合储能系统(Hybrid Energy Storage System,HESS),为充分发挥HESS的性能优势,本文从储能单元、储能模块和储能系统三个层面,开展了数学建模、优化分配、能量管理等方面的研究,为独立光储系统的应用提供理论和方法支持。首先,介绍独立光储系统结构,并分析系统中PV、VRB和SC三种元件的数学模型、工作特性及变换器控制。针对PV单元采用最大功率点跟踪-恒压控制;针对VRB采用恒流-恒压控制;针对SC采用功率环-电流环控制。然后,搭建模块化混合储能系统架构,给出双层功率优化分配策略即“上层优化-下层分配”。在“上层优化”中,综合考虑储能模块的最大补偿功率和剩余可充/放电容量进行功率分配,以HESS全寿命周期成本为目标函数构建优化分配模型,运用改进布谷鸟算法分析不同权重参数对系统稳定性及成本的影响。在“下层分配”中,采用变分模态分解法对储能单元的输入/出功率进行分配,给出利用Hilbert变换求解子模态信号的瞬时频率来确定分解层数,能够有效地缓解模态混叠和信号过分解现象。最后,给出一种考虑储能模块剩余容量的独立光储系统能量管理策略,根据系统所处的不同状态合理划分工作模式,根据工作模式选择相应的控制电路,提高了系统的灵活性。仿真结果说明系统在不同工作模式间可以实现快速、平滑切换。搭建独立光储系统关键技术的验证平台,包括基于Matlab GUI的半实物仿真平台和光储一体化系统实证平台。半实物仿真平台验证了独立光储系统的功率优化分配和能量管理控制策略的正确性;实证平台验证了能量管理系统控制功能的有效性。更多还原

【Abstract】 Vigorously developing photovoltaic(PV)power generation can alleviate the problems of energy shortage,power supply shortage and environmental pollution in China.Independent photovoltaic energy storage system does not rely on power grid operation,and has been widely used in places without electricity or frequent blackouts.In the operation process of photovoltaic energy storage system,the instantaneous power balance,system stability and safe operation should be ensured.Therefore,how to effectively solve the problems of power distribution and energy management control of photovoltaic energy storage system is still imminent.In this study,super capacitor(SC)and vanadium redox batteries(VRB)were selected to form a hybrid energy storage system(HESS).In order to give full play to the performance advantages of HESS,this thesis studies the mathematical modeling,optimal distribution and energy management from the three levels of energy storage unit,energy storage module and energy storage system,so as to provide theoretical and methodological support for the application of independent photovoltaic energy storage system.Firstly,the structure of stand-alone photovoltaic energy storage system is introduced,and the mathematical model,working characteristics and converter control of PV,VRB and SC components in the system are analyzed.Maximum power point tracking-constant voltage control is adopted for photovoltaic cells;constant current-constant voltage control is adopted for all vanadium flow cells;power loop-current loop control is adopted for super capacitors.Secondly,the modular composite energy storage system architecture is built,and the two-layer power optimal distribution tactic is proposed,namely "upper optimal configuration-lower power distribution".In the " upper optimal configuration ",the maximum compensation power and the residual charging / discharging capacity of the energy storage module are considered for power distribution.Taking the HESS life cycle cost as the objective function,the optimal allocation model is constructed.The improved cuckoo algorithm is used to discuss the influence of different weight parameters on system constancy and configuration cost.In the " lower power distribution ",the variational mode decomposition method is used to distribute the power of the energy storage unit.The instantaneous frequency of the sub-modal signal is solved by Hilbert transform to determine the number of decomposition layers,which can effectively alleviate the phenomenon of mode overlap and signal over decomposition.Finally,an energy management tactic of stand-alone PV energy storage system considering the residual capacity of the energy storage module is proposed.Dividing the working pattern according to the different states of the system,and selecting the corresponding control circuit on the basis of the working pattern,which improves the flexibility of the system.The emulation results indicate that the system can toggle apace and smoothly in five working modes.Build the verification platform of key technologies of independent photovoltaic energy storage system,including hardware in the loop simulation platform based on Matlab GUI and demonstration platform of photovoltaic energy storage integrated system.The hardware in the loop simulation platform verifies the correctness of the optimal power allocation and energy management control strategy of the stand-alone photovoltaic energy storage system,the experimental platform verifies the effectiveness of the control function of the energy management system.更多还原