时变相量下基于陷波滤波算法的下垂控制方法改进

Improved droop control method based on notch filtering algorithm using time-varying phasor

传统下垂控制中忽略了功率测量对电压频率有差控制的重要性,功率的测量往往通过一阶低通滤波器来获得,由于低通滤波器低频极点的存在,导致带宽受到限制。因此必须在响应速度与功率纹波抑制之间做出权衡;孤岛逆变器运行系统中,下垂参数的选取对于系统的稳定性和动态响应有着很大的影响,传统准静态相量忽略了系统中动态变化的成分,理论上稳定的控制参数可能导致实际运行系统的不稳定。基于此引入了陷波滤波算法建立了感性系统下时变相量小信号模型,给出了更为精确的参数选择范围,在分析系统动态过程的基础上解释了准静态模型下稳定区域增大的原因。陷波滤波算法改善了功率纹波抑制效果和系统响应速度,仿真和实验验证了所提出方法的合理和有效性。

Conventional droop method ignores the importance of power measurement on difference control of voltage frequency. Power measurements are usually obtained by first-order low-pass filters. The bandwidth is limited due to the inherent low frequency pole. So there must be a trade-off between a suitable power ripple rejection and response time. In the isolated inverter operating system,the selection of droop parameters has a great influence on the stability and transient response of the system. The traditional quasi-stationary phasor neglects the components of dynamic changes in the system,theoretically,the stable control parameters may lead to the instability of the actual running system. On this basis,the notch filtering algorithm is introduced to establish the small signal model using time-varying phasor in inductive system,and a more accurate parameter selection range is given. On the basis of analyzing the dynamic process of the system,the reason for the expansion of the stable region in the quasi-static model is explained. The notch filtering algorithm improves the power ripple rejection and the speed of system responsiveness. Both simulation and experimental results verify the validity and effectiveness of the proposed method.