Research on the Control Mechanism of DC Capacitor Voltage of SSSC Based on Multi - pulse VSC

The characteristics of Static Synchronous Series Compensator (SSSC) based on six-pulse Voltage Source Converter (VSC), which is inserted in series into a three phase inductive system, are analyzed and calculated in detail in its inductive and capacitive operation modes, including the AC, DC current and DC capacitor voltage in one period. And the expressions for them are derived in order to assess the compensator performance. The SSSC based on six-pulse VSC is specially studied because it gives an insight into the study of the more complex configurations. On the basis of calculations and simulations in PSCAD/EMTDC, the impact of current on DC capacitor charge and discharge is analyzed thoroughly. A methodology for the capacitor voltage control of SSSC is obtained. Meanwhile, a basis for choosing semiconductor devices of SSSC is presented in the paper.