电压跌落下虚拟同步发电机故障穿越控制

针对虚拟同步发电机(Virtual Synchronous Generator, VSG)传统平衡电流控制在电压发生跌落时无法实现穿越问题,提出一种满足VSG平衡电流控制的低电压穿越(Low Voltage Ride-Through, LVRT)控制策略。分析了VSG传统平衡电流控制基本原理以及在电压跌落时无法实现穿越的原因。在此基础上,提出一种限功率给定的控制方案。按照传统LVRT电流指令计算出功率给定值,在维持VSG机械惯性属性不变的前提下,通过减小无功环惯性系数和维持有功功率差额以改善系统对称故障时无功输出速率和有功调节时间,引入相位调节控制消除了故障解除瞬间系统功率失稳问题。仿真结果验证了该控制策略的正确性和有效性。

Fault ride-through of virtual synchronous generator under voltage drop

According to the problem that the traditional VSG balanced current control is not able to ride through faults during the voltage drop, a Low Voltage Ride-Through (LVRT) control strategy is proposed to meet the VSG balanced current control. The basic principle of VSG balanced current control and the reason why it cannot ride through low voltage fault are analyzed, on this basis, a control method of power limit is proposed. According to the traditional LVRT current command, the power reference value is calculated. Under the premise of maintenance of VSG mechanical inertia properties, and by reducing the reactive ring inertia coefficient and maintaining active power difference, the system reactive power output rate and active adjustment time are improved during symmetrical fault, the problem of power instability during the fault release is eliminated by introducing a phase adjustment. The validity and effectiveness of this control strategy is verified by simulation results. This work is supported by Natural Science Foundation of Inner Mongolia Autonomous Region (No. 2016BS0508).