低压微网中永磁风力发电系统逆变器并网/孤岛模式控制切换（英文）

Inverter Control Switching Between Grid-connected and Islanding Operating Modes of Permanent Magnet Wind Power Generation System in Low-voltage Microgrid

在低压微网中,以永磁风力发电并网系统的逆变器为研究对象,主要研究了风力发电系统在并网和离网两种模式下系统逆变器的控制策略。由于风能自身的特点,风力发电系统可能处于并网和脱网两种模式下运行,而系统中逆变器的控制性能成为系统平滑稳定切换的核心之一。该文提出了一种新的并网逆变器在不同的运行模式下的控制策略。当系统并网运行时,逆变器电流内环采用瞬时电容电流改进的谐振控制,解决了因LCL三阶滤波器引起的系统震荡问题,且输出电流具有良好的动态跟踪性能;电压外环采用瞬时平均功率跟踪控制,实现了逆变器按给定功率稳定输出,保证了发电系统向电网馈入高质量的电能。当系统脱网运行时,电压外环采用基于无功下垂系数调节的电压PI控制,内环控制保持不变,当负载突然改变时,保证了发电系统具有较快动态响应性能,且向负载提供稳定功率。经过仿真分析,有效验证了所提控制策略的准确性和可靠性。

In low-voltage microgrid（LVMG）,inverters of permanent magnet wind power generation system were researched,focusing on the control strategies for inverters of the permanent magnet wind power generation system in grid-connected and islanding modes.Given the characteristics of wind energy,wind power generation systems may operate under two operating modes,i.e.,grid-connected and off-grid.Moreover,the system＇s inverter control strategy is the core technology that ensures the system＇s smoothness and stability under different operating conditions.This paper presented a novel control strategy for grid-connected inverters under different operating modes.When the system is under grid-connected operation,the system shock caused by an LCL third-order filter can be solved by using an improved instantaneous multi-resonant capacitor current control in the inverter current inner ring,and then a given inverter＇s output power stability can be achieved by using an instantaneous average power tracking control in the voltage outer ring.Withthe use of this novel control strategy under an operating grid when a given power is mutated,the current system shows good dynamic tracking performance,which ensures the high quality of the power delivered to the grid system.When the system is running in the off-grid mode using PI in the voltage outer ring,and the inner loop control remains unchanged,with a sudden load increase or reduction,the proposed strategy ensures that the power system has a faster dynamic response performance and provides stable power to the load.Simulation analyses verify that the novel control strategy presented in this paper is accurate and reliable.