模块化多电平换流器IGBT状态参数在线监测方法*

考虑模块化多电平换流器(Modular Multilevel Converter ,MMC)可靠性与关键元件参数密切相关,本文提出一种针对其子模块(Submodule, SM)中绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor, IGBT)状态参数估计的新方法。首先分析子模块开关状态量与电压的关系并建立桥臂电压数学模型；针对通过传感器采集的桥臂数据存在测量噪声,引入卡尔曼滤波理论,在线性最小方差准则下,建立了MMC子模块IGBT状态参数监测信息的数学模型,从而得到桥臂各子模块IGBT状态参数。该方法仅利用输电系统中已布置传感器,无需添加新的采集点,在不增加量测系统复杂度的同时有效降低投资成本与采样开销。最后,在PSCAD/EMTDC仿真平台中搭建了MMC-HVDC的电磁暂态仿真模型,通过仿真验证了所提出的估计算法的有效性,且能有效消除桥臂传感器噪声的影响。该方法对提高监测系统的便携性,降低成本和能耗,有一定的参考价值。

An Online Monitor Method for IGBT state parameters for Modular Multilevel Converter Using Kalman Filter

Considering the reliability of modular multilevel converter (MMC) closely related to key component parameters, a novel parameter estimation method is proposed for insulated gate bipolar transistor (IGBT) of submodule (SM) in MMC. The relationship between the switch status and the voltage of submodule is analyzed and the model of the bridge arm voltage is established. Kalman filtering theory is introduced against the measurement noise of the bridge arm data from sensors. Under the linear minimum variance criterion, the model of the IGBT parameter monitoring information in MMC submodule is established to obtain the IGBT parameters from each submodule in the bridge arm. The substantial reduction in the number of voltage sensors improves the system reliability and decreases its cost and complexity. This method can also effectively eliminate the influence of sensor noise. Finally, the effectiveness of the proposed technique is validated via a PSCAD/EMTDC simulation analysis of a three-phase MMC-HVDC. The method has certain reference value for improving the portability of the monitoring system and reducing the cost and energy consumption.