基于频率稳定性提升的虚拟惯性优化控制策略

A virtual inertia optimization control strategy based on frequency stability improvement

基于传统一阶虚拟惯性的新能源逆变器并联弱电网时,其有功稳态和动态特性调节存在矛盾。首先,总结了基于各种改进结构虚拟惯性算法的新能源逆变器并、离网时的特性及存在问题。然后,针对此问题,以频率稳定性提升为目标,通过调整二阶虚拟惯性算法中一阶微分补偿环节和一阶惯性环节在功率外环前向通道的位置,提出了二阶虚拟惯性优化控制策略。最后搭建了一台100 kW新能源逆变器并网仿真平台,对理论分析结果进行仿真验证。理论分析与仿真结果表明,该算法在保证逆变器有功稳态特性和功率振荡抑制能力的同时,有效减小了动态响应初始阶段的频率变化率,提高了系统频率稳定性。

When a new energy inverter with traditional first-order virtual inertia is connected to a weak power grid,there is an adjustment contradiction between its output active power steady-state and dynamic characteristics.First,the characteristics and problems of the new energy inverter with various improved structural virtual inertia in stand-alone and grid-connected mode are summarized.Then to promote frequency stability,a second-order virtual inertia optimization control strategy is proposed,one which adjusts the positions of the first-order differential compensation link and the first-order inertia link in the outer power loop forward channel of the second-order virtual inertia algorithm.Finally,a100 kW new energy inverter grid-connected system simulation platform is built to verify the theoretical analysis.Theoretical analysis and simulation show that the proposed algorithm effectively reduces the frequency change rate in the initial response stage and improves system frequency stability while maintaining the active power steady-state characteristics and power oscillation damping ability.