A constant duty cycle control, single-phase inverter design for distributed static series compensators

Distributed static series compensators (DSSC) are power electronics devices that can inject positive or negative reactance in series with a transmission line by connecting through a transformer suspended from the line. This paper presents a method of controlling the DSSC inverter for improved functionality. It is shown that using three-level, constant duty cycle switching compared to traditional, sinusoidally modulated three-level switching increases the energy available in the inverter dc-side capacitor and thus the magnitude of injected reactance. Furthermore, losses in the inverter are reduced. These results are validated on a 5kVA, single-phase inverter implemented in hardware.