采用卡尔曼滤波算法的模块化多电平换流器电容值在线估计方法

为预防模块化多电平换流器中子模块电容器老化失效而引发系统安全问题,提出一种模块化多电平换流器子模块电容器电容值在线估计方法.首先,采用卡尔曼滤波滤除传感器采集桥臂信息存在的测量噪声;然后,利用传感器监测桥臂电流和子模块电压信息并对其进行离散化处理,建立电容、电压及电流的数学模型,实时估计子模块电容值的情况;最后,在PSCAD/EMTDC仿真平台上搭建8电平系统进行仿真验证.结果表明,所提出的方法稳态时估计误差在1%以内,能够实现在线估计,有利于预测性防护,提高系统的可靠性.

Online estimating method for modular multilevel converter capacitor based on Kalman filtering

In order to prevent the aging failure of sub-module capacitors in modular multilevel converters and lead to system safety problems, an online estimating method for modular multilevel converter capacitors is proposed. First, there is measurement noise for the sensors acquisition bridge arm information, and the noise is filtered by Kalman filter; Then, the sensors are used to monitor the arm current and the SM voltage information, and the discretization processing is performed to establish a mathematical model of capacitance, voltage and current, and the submodule capacitance is estimated in real time; Finally, an 8-level system is built on the PSCAD/EMTDC simulation platform for simulation verification. The results show that the estimated error of the proposed method is less than 1%, which can realize online estimation and is conducive to predictive protection and improve system reliability.