隔离型链式储能系统优化设计研究

针对分布式发电渗透率不断提高引起的交流电网频率波动愈发频繁问题,提出一种基于隔离型DC/DC变换器的链式储能装置设计方法。结合载波移相调制的最大电平数条件和隔离型变换器的功率传输极限,详细说明功率双向调节区间的设计方法。建立了最大放电时长一般模型,依次分析基于双有源桥、双半桥型隔离变换器的储能装置放电时长特征,得出了放电时长对变换器种类、变比、漏感、超级电容数量的关系,表明在固定放点时长指标下,优化设计隔离型变换器有助于实现漏感集成、隔离变压器便于制造、降低储能成本。最后,仿真证明了所提方案在功率指令大小、类型、方向突变时控制精度较高,有助于装置输出功率实时跟随自动发电控制(AGC)指令。

Optimization design of isolated cascaded energy storage system

For frequency fluctuation of AC power grid caused by the continuous increasing of distributed generation permeability, a design method of cascaded energy storage device based on isolated DC/DC converter is proposed in this paper. Combined with the maximum level condition of carrier phase-shift modulation and the power transmission limit of isolated converter, the design method of bi-directional power regulation region is described in detail. The general model of maximum discharge time is established, and the discharge time characteristics of energy storage device based on double active bridge and double half bridge isolated converter are analyzed in turn. The relationship between discharge time and converter type, transformation ratio, leakage inductance and supercapacitor quantity is obtained, which shows that the isolated converter optimization benefits to leakage inductance integration, easier manufacture of isolation transformer and reduce energy storage cost under the fixed discharge time index. Finally, the simulation results show that the proposed method has high control accuracy when the size, type and direction of power instructions change suddenly, which is helpful for the output power of the device to follow the AGC instructions in real time.