中文摘要：

为了探究电容换相换流器中串联电容的取值问题,建立了电容换相换流器（capacitor commutated converter,CCC）的稳态模型,并利用Matlab软件进行数学分析,探讨了串联电容补偿度与串联电容电压、阀电压、阀峰值电压、直流电流、换相重叠角、触发角、视在熄弧角和实际熄弧角之间的关系,最终给出合适的串联电容补偿度的取值范围并进行仿真验证。研究结果表明：补偿度的取值上、下限分别由阀峰值电压和实际熄弧角决定,其中阀峰值电压为主要限定因素;补偿度的可选范围涵盖欠补偿、全补偿和过补偿3种状态,且全补偿状态下CCC系统不会发生串联谐振;得出强受端系统下补偿度的可选范围为[0.92,1.4],而弱受端系统补偿度的可选范围为[0,1.08]。

英文摘要：

In allusion to the problem that how to take the value of the series capacitor in capacitor commutated converter （CCC）, a steady state model of CCC is established. Through the Matlab software based mathematical analysis, the relation of the series capacitor compensation degree with the voltage of series capacitor, valve voltage, the peak voltage of the valve, the DC current, the commutation overlap angle, the commutation overlap angle, the firing angle, the apparent extinction angle and the actual extinction angle are revealed, and finally the appropriate range to take the value of the compensation degree of the series capacitor is given and validated by simulation results. Results of this research show that the upper limit and the lower limit of the value of compensation degree are determined by peak voltage of the valve and the actual extinction angle respectively, and the peak voltage of the valve is the main limiting factor; the selectable range of the compensation degree should cover three states, namely the undercompensation, the full compensation and the overcompensation, and the there is no series response in the CCC system under full compensation; it is proposed that for the circumstance of strong receiving AC system the selectable compensation degree should be within the range from 0.92 to 1.4 and for the circumstance of weak AC system the selectable compensation degree should be within the range from 0 to 1.08.