随着海上风电、光伏等新能源的大规模建设,产生了直流输电、交直流互联和储能的应用需求.目前储能技术的研究和应用主要集中于交流储能领域.模块化多电平电池储能系统(modular multilevel converter based battery energy storage system,MMC-BESS)虽然在交直流互联的同时,实现了储能的功能,但电池中流过的工频、二倍频等脉动电流成分对电池寿命有潜在影响,且传统的模块化多电平(modular multilevel converter,MMC)换流站的改造成本高.本工作提出的直流直挂储能装置将换流和储能分离,电池电流仅为直流和高频脉动成分,工况对电池友好,且直流直挂储能系统需要电池单体数量仅为MMC-BESS的1/6,成本低.对直流直挂储能装置的拓扑结构及工作原理进行分析;对级联子模块的数量和参数进行设计;基于载波移相调制,推导直流纹波电流,进而对并网电感参数进行设计;建立直流直挂储能装置的数学模型,推导控制模型,根据控制框图进行功率控制.最后,通过仿真和样机实验,验证该半桥拓扑级联型直流直挂储能装置设计的可行性及正确性.实验证明,该设计和控制方法效果良好,对高压大容量直流直挂储能装置的设计有一定参考价值.
Design of DC direct-mounted energy storage device with cascaded half-bridge topology
The escalation in the construction of new energy sources,such as offshore wind power and photovoltaics,has increased the demand for applications in DC transmission,AC-DC interconnection,and energy storage.Presently,research and applications in energy storage technology predominantly focus on AC energy storage.Although the modular multilevel converter based battery energy storage system(MMC-BESS)facilitates energy storage while interconnecting AC and DC networks,the presence of pulsating current components,including power and double frequencies,in the battery can adversely affect battery life.Moreover,the cost associated with retrofitting traditional modular multilevel converter(MMC)converter stations is significant.The proposed DC direct-mounted energy storage device decouples the converter and energy storage functions,ensuring that the battery current comprises only DC and high-frequency pulsation components,thus offering a battery-friendly operating environment.Furthermore,the DC direct-mounted energy storage system necessitates merely one-sixth the number of battery cells required by MMC-BESS,leading to cost reductions.This paper delves into the topology structure and operational principles of DC direct-mounted energy storage devices,designs the quantity and parameters of cascaded submodules,calculates the DC ripple current through carrier phase-shift modulation,and designs the parameters of the grid-connected inductance.It also establishes the mathematical model of the DC energy storage device,derives the control model,and implements power control based on the control diagram.The feasibility and accuracy of the cascaded half-bridge topology in DC direct-mounted energy storage devices are corroborated through simulation and prototype experiments.The experiments demonstrate the effectiveness of the design and control methods,offering valuable insights for the design of high-voltage and large-capacity DC energy storage devices.
DC direct-mounted energy storagecascade half bridgegrid connected inductancecarrier phase shift modulationpower control
国家科技期刊平台
NSTL
万方数据
