Voltage-Controlled and Current-Controlled Low Voltage STATCOM: A Comparison

Abstract

Inverter-based converters interconnecting DC microgrids and AC-microgrids/grids are in a strong expansion. Besides power exchange, the inverter can be requested to furnish ancillary services and, among them, power factor compensation. This work presents a comparison between voltage control and current control in a low voltage inverter in a STATCOM operation. Both strategies use P&O controllers to control power factor, but in voltage-control the P&O adjust modulation index while in current-control P&O adjusts the current reference. HIL simulations show that both controllers can efficiently increase power factor; however, voltage control requires additional overcurrent protection. Current control can easily limit the devices current, but requires an extra current measurement when compared to the voltage controller, therefore has increased cost.