混合储能系统在风光互补微电网中的应用

Application of Hybrid Energy Storagy System on Wind/Solar Hybrid Microgrid

光伏发电和风力发电输出功率具有间歇性和随机性的特点,为了提升微电源的性能,将储能装置应用于风光互补的微电网中。采用超级电容与蓄电池的混合储能系统,通过对DC/DC变换器控制策略的合理设计,实现了蓄电池恒流充放电,延长了使用寿命;针对传统PID控制的不足,采用响应速度更快、控制效果更好的滑模变结构控制方法;为了平抑风光互补微电网并网功率,并在孤岛运行时提供稳定的电压频率支持,采用低压微电网的下垂控制策略。在孤岛运行时,分别在风速、光照强度改变以及负载变化的情况进行了仿真评估混合储能系统的性能,结果表明,混合储能系统能够提高风光互补微电网的电能质量。

The output power of PV and wind power generation have the characteristics of intermittent and randomness. In order to enhance the performance of micro-power, energy storage is employed in a wind/solar hybrid microgrid. The paper adopts a hybrid energy storage system composed of supercapacitors and batteries. Charge and discharge currents of batteries are constant, and also extend their lifetime with optimalcontrol of the bi-directional DC/DC converter. Com- pared with traditional PID control, the sliding-mode and variable-structure control has the advantages of faster response speed and better control effect. In order to balance the grid-connected power and provide the necessary voltage and fre- quency reference in islanding operation, the droop control strategy is used in low voltage microgrid. The performance of new hybrid energy storage system is evaluated through simulation under changing solar irradiance ,wind velocity and load in isolated island operation model. The result indicates the hybrid energy storage system can boost power quality of the wind/solar hybrid microgrid.