A Capacitance Matrix Expansion Method for Parasitic Capacitance Extraction of Excitation Winding

Abstract

The excitation voltage regulator is connected to the excitation winding of the generator to regulate the output power of the generator. The excitation winding is multicircuit winding with multi layers and multi turns. The parasitic capacitance is significant, and it leads to some problems, such as current overshooting and switching losses of the excitation voltage regulator. Therefore, the extraction of the parasitic capacitance of the excitation winding is necessary. A capacitance matrix expansion method is proposed in this paper. The matrix of the parasitic capacitance of the excitation winding is obtained. Due to the symmetric arrangement of the excitation winding, the capacitance matrix can be divided into many parts. The capacitance values of each part approach to a constant which is called the typical capacitance value. The full capacitance matrix is deduced according to the typical capacitance values. After the full capacitance matrix being transformed and simplified, the lumped parasitic capacitance of the excitation winding can be extracted. This method can both take the most advantage of the flexibility of FEA and avoid the unaffordable hardware requirement when extracting the parasitic capacitance of the multicircuit windings. The simulations and experiments are performed for the validation of this method.