基于数值逼近与值集分析的多直流间换相失败预测模块参数优化研究

Parameter Optimization of Commutation Failure Preventions Between Multiple DC Links Based on Numerical Approximation and Value Set

直流换相失败预测等附加控制策略具有开关特性,所以关键的电气输出量可作为系统稳定指标。提出了一种能够优化多个换相失败预测模块中参数配置的分析方法。首先采用非侵入式多项式或有理分式数值逼近法快速确定稳定指标与多参数之间的输入输出关系式。然后采用一种值集分析方法,将稳定指标含参表达式与临界值结合,构造一个二维值集函数。在复平面上的值集图提供了多参数问题的可视化分析结果,揭示了多直流换相失败预测模块参数对系统暂态响应的不同影响,有助于优化多参数协调整定,改善暂态响应,从而提高混联电网稳定性。

With the switching features of the additional control strategies in hybrid grids, such as commutation failure preventions(CFPREVs), some key electrical outputs can be regarded as the system stability indexes. This paper presents an intuitive method for the systematic analysis of the parameter optimization of multiple CFPREVs. The I/O expressions between the stability indexes and parameters are quickly determined by non-intrusive polynomial or rational fractional numerical approximation. Using a novel value set method, the expressions and the critical values of the stability indexes are used to construct a two-dimensional function. Its corresponding plots in the complex plane provide interesting visual results to intuitively reveal the different impacts of the different parameters of CFPREVs on the transient response. The proposed method is helpful to optimize the multiparameter configuration and improve the system stability.