级联型超导储能系统的整体协调控制方法

提出了级联型超导储能系统的整体协调控制方法，当系统未产生电压凹陷时，级联型逆变器通过相位控制实现对超导磁体的充电和电流维持；当系统产生电压凹陷时，通过状态空间反馈的方法迅速实现完全补偿，以保护电压敏感的负载；当凹陷解除时，又通过相角的渐变从电网吸收能量，以补偿超导磁体中能量的消耗。同时，在电流调节器的控制中，采用统一PI电压控制模式以保持级联逆变器直流母线电压的稳定。系统仿真结果表明，本文提出的方法控制电压凹陷的效果较好。

A System Control Strategy for Cascaded Superconducting Energy Storage System

A holistic coordinated control approach for cascaded superconducting energy storage system (SMES) is proposed in this paper. In this control approach, the cascaded multilevel inverters are controlled by phase-angle control strategy to implement the charging of superconducting magnet and to maintain the current in the superconducting coil constant while voltage sag does not occur; to protect voltage-sensitive loads, the complete compensation can be quickly implemented by state space feedback control strategy while voltage sag occurs. When voltage sag diminishes, the phase reference angle is also gradually changed to absorb energy from the utility to compensate the energy consumed during voltage sag compensation. Meanwhile, during the control of current regulator, the unified PI voltage control mode is adopted to maintain the DC bus voltage of cascaded multilevel inverters constant. Simulation results show that the proposed control approach for cascaded superconducting energy storage system can effectively cope with voltage sag.