【作者】 王健；

【导师】 金建勋； 郑陆海；

【作者基本信息】 天津大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 为优化现有的能源结构,实现能源的可持续利用,近年来微电网得到了迅速发展,与微电网相关的一系列控制技术成为国内外研究的热点,微电网的电能质量控制策略则是其中关键技术之一。由于微电网的电能质量不仅与内部的分布式电源、储能装置以及负荷的运行特性有关,还受到外部配电网电压故障的影响,本文研究了基于光伏-混合储能统一电能质量调节器(Unified Power Quality Conditioner,UPQC)的控制与能量管理策略,使其在对微电网电能质量进行综合治理的同时,还能实现微电网功率的快速平衡,具体内容如下:(1)研究了UPQC兼具电能质量治理和光伏逆变双重功能的跟踪控制策略。首先,研究了滑模SVPWM控制策略,该策略改善了UPQC串联单元在配电网故障条件下,尤其是在非对称故障条件下对微电网电压的补偿效果;其次,研究了UPQC并联单元在并网模式下的多目标控制策略,实现了微电网内部电能质量治理和光伏逆变的功能;然后,研究了并联单元在孤岛模式下的U/f控制策略,为交流母线上的负载提供了电压和频率支撑;最后,研究了孤岛锁相技术和预同步控制策略,保证了微电网运行模式的平滑切换。(2)研究了基于蓄电池-超导磁储能混合储能的滑模下垂控制策略。根据蓄电池和超导磁储能的工作特性,将超导磁储能作为一级储能装置,通过滑模控制来维持直流母线的电压稳定以优先平抑微电网中的功率波动;而蓄电池则作为其后备储能,根据超导磁储能的荷电状态采用下垂控制确定蓄电池输入/输出功率,然后通过滑模控制实现蓄电池的充/放电运行,使得超导磁储能的荷电状态一直处于限制区间的同时,也极大地降低了蓄电池的充放电次数和自身放电率,延长其循环使用寿命。(3)研究了光伏-混合储能系统的能量管理策略。在微电网并网和孤岛两种运行模式下,基于蓄电池和超导磁储能荷电状态的能量管理策略均能够灵活有效地管理微电网各单元之间的功率流动,最终实现微电网功率的快速平衡。(4)在Matlab/Simulink环境下对基于光伏-混合储能UPQC的控制和能量管理策略进行仿真分析,仿真结果验证了本文所提的控制与能量管理策略的可行性和有效性。更多还原

【Abstract】 In order to optimize the existing energy source structure and realize the sustainable utilization of energy,microgrid has advanced rapidly in recent years.A series of crucial technologies in connection to microgrid have been extensively investigated.Among them,power quality control strategy is one of the crucial technologies.Since the power quality of the microgrid is not only correlated with the operating characteristics of distributed power sources,energy storage devices,and various loads,but also influenced by grid faults,a novel control and energy management strategy is proposed in this paper for unified power quality conditioner(UPQC)based on photovoltaic(PV)and hybrid energy storage system(HESS).The proposed scheme can not only comprehensively deal with the power quality issues,but also balance power quickly in microgrid.The details are as follows:(1)The tracking control strategy of UPQC with the dual functions of solving power quality problems and photovoltaic power generation is studied.Firstly,the sliding mode SVPWM control strategy is proposed to improve the compensation performance of the UPQC series converter for microgrid voltage under the grid fault conditions,especially under the asymmetric fault conditions.Secondly,the multiobjective control strategy for controlling the UPQC parallel converter in the gridconnected mode is studied,which solves the internal power quality issues of the microgrid and implements the photovoltaic generation.In addition,the U/f control strategy for controlling the parallel converter in island mode is investigated,which supplied voltage and frequency supports for the loads on the AC bus.Finally,the islanding phase-locking technology and pre-synchronization control strategy are studied to ensure the smooth switching of the microgrid operation mode.(2)Sliding mode droop control strategy is proposed for HESS based on battery energy storage system(BESS)and superconducting magnetic energy storage(SMES).According to the operating characteristics of BESS and SMES,SMES is utilized as a primary energy storage device,using sliding mode control method to maintain a constant DC bus voltage for prioritizing the suppression of power fluctuations in the microgrid.While BESS is used as backup energy storage for SMES,the input/output power of BESS is determined according to the state of charge(SOC)of SMES using droop control,and then the sliding mode method is utilized to control the charge/discharge operation of the BESS,so that the SOC of SMES is always within the limit.Meanwhile,the charge/discharge times and its own discharge rate of BESS are greatly decreased,extending its service life.(3)An energy management scheme is proposed for PV-HESS-based system.In the grid-connected and island operation modes of microgrid,the energy management scheme based on the SOCs of BESS and SMES is able to flexibly and effectively manage the power flows in the various parts of the microgrid,ultimately to implement the power balance quickly in microgrid.(4)In Matlab/Simulink environment,the proposed control and energy management strategies for PV-HESS-based UPQC are simulated and analyzed.Simulation results validate the feasibility and effectiveness of the control and energy management strategy proposed in this paper.更多还原