基于Z源逆变器的STATCOM／BESS控制策略研究

摘要

将基于Z源逆变器的STATCOM与电池储能系统（ BESS）通过双向DC／DC变换器相结合，实现了有功功率和无功功率的同时补偿。针对传统电压源型逆变器效率低、抗电磁干扰能力差且需加入死区等缺点，采用Z源逆变器STATCOM可有效解决上述问题。在分析其工作原理的基础上，推到了基于同步旋转坐标系的STAT-COM离散化数学模型，设计了无差拍电流内环离散控制器和外环控制器，顺利实现了有功、无功的解耦控制，具有控制简单、控制精度高，鲁棒性强等优点。为了保证BESS安全充放电的稳定运行，提出一种新型的BESS充放电控制策略：外环采用恒功率、恒压和涓流切换控制，内环采用电感电流为控制目标。最后，仿真和实验结果验证了所提出的上述控制策略的正确性和优越性。%STATCOM based on Z-source inverter is combined with energy storage system ( BESS ) through DC/DC converter in this paper , which not only can compensate the reactive power , but also can compensate the active power . Aiming at the traditional inverter has the following disadvantages:the lower inefficiency , susceptible to electromagnet-ic interference and needs join the dead-time, this paper proposes the STATCOM based on Z-source inverter to solve the above problems.Firstly, it deduces the discrete mathematical model in dq rotating coordinates by analyzing its fundamental principles .Then, the inner controller based on dead-beat discrete model control and outer controller are designed , which achieves the active power and active power decoupled control successfully .This control strategy has the advantages of easy control , high control accuracy and strong robustness and so on .In order to make sure that the BESS can operate steadily with discharging and charging , this paper proposes a novel three steps control strategy .The inner loop controls the inductance current , and the outer loop controls the constant power , constant voltage and trickle charging .Finally, the simulation and experiment results test and verify the correctness and superiority of the proposed control strategy .