基于同步开关预判的半桥型VSC快速电磁暂态建模方法

现代电力系统存在大量的半桥型电压源变流器,采用传统电磁暂态仿真程序对其进行大规模仿真分析时,存在耗时高、效率低的问题.以半桥子电路为开关状态判断的基本单元,通过分析其开关状态变化时二极管的续流及关断过程,得出普适于半桥型电压源变流器的同步开关预判方法.该方法可在当前时步通过逻辑判断直接得出稳定的开关状态组合,消除了迭代计算.结合同步开关快速预判方法及内节点收缩方法构建了半桥型电压源变流器的快速仿真模型,通过对比仿真,验证了快速仿真模型具有与全详细化模型相当的仿真精度,且能有效减少仿真耗时,提高仿真效率.与全详细化模型相比,针对80模块固态变压器的快速仿真模型可加速20倍.

Fast Electromagnetic Transient Modeling Method for Half-bridge-Type Voltage Source Converter Based on Synchronous Switch Prediction

Half-bridge type voltage source converter (VSC) is widely used in the modern power system. When the traditional electromagnetic transients program (EMTP) is used to simulate a large-scale VSC network, there are problems of high time-consuming and low efficiency. Taking the half-bridge sub-circuit as the basic unit for the switch state judgment, by analyzing the freewheeling and turning-off process of the diode when the switch states change, a synchronous switch prediction method that is generally suitable for the half-bridge-type VSC is obtained. This method can directly obtain the stable switch state combination through logic judgment at the current time step, while eliminating the iterative calculation. A series of fast simulation models of the half-bridge type VSC are constructed by combining the fast prediction method of synchronous switch and nested node elimination method. Comparative simulation results verify that the proposed fast simulation models have the same simulation accuracy as the full-detailed models, and can effectively reduce the simulation time and improve the simulation efficiency. The simulation on an 80-module solid-state transformer using the fast simulation model can be accelerated by 20 times compared to the full-detailed model.