中文摘要：

大功率逆变器的动态特性在线测试是电力电子逆变器的一个重要研究方向。多电平系统由于元器件多，结构复杂，其开关动态在线测试极为困难，但此工作对于设计、研制高性能逆变器系统，实现状态监测、故障预防，提高逆变器工作的可靠性有着重要的意义。该文研究大功率三电平逆变器开关器件的动态特性在线测试方法，提出多电平逆变器功率开关状态可测性的概念。所提的方法很好地解决了在线测试的几个关键问题，包括：海量数据的传输处理、全状态参数同步检测控制、功率器件开关过程的高速数据采样、系统状态参数的直接和间接的提取和推算等。在750kVA三电平变频调速系统上成功实现了各种负载工况下的实时在线测量。该文所讨论的开关特性在线测试方法和系统可有效扩展到三电平以上的多电平实时在线测试技术中。

英文摘要：

The on-line test of dynamic performances in high power three-level inverters is one of the important parts in power electronics inverter research fields. Multiple-level inverters have many devices and complex topologies, so it is difficult to accomplish the on-line test of the switching dynamic performances. However the online test plays significant roles in highly efficient inverter system design, condition monitoring, precaution against malfunction and reliability improvements in inverters. This paper worked on an on-line test method of switching dynamic performances of the high power three-level inverter, and brought out the conception of state testability of power device switching modes in multiple-level inverters. The method presented in this paper solves some key problems in the on-line test very well, including mass data transmission and process, simultaneously detecting device states in all modes, high speed sampling during power device switching, direct and indirect extraction and calculation of system parameters, and so on. At last, the on-line test has successfully been applied in 750 kVA 3-level VVVF system in different load conditions. Moreover, the on-line test method and system can also be effectively used for other multiple-level inverters.