Inverter control using output feedback for power compensating devices

This paper presents an inverter control strategy using output feedback control. The controller is designed in discrete-time using a pole shifting law in the polynomial domain that radially shifts the open-loop system poles towards the origin. This type of inverter control is very useful for custom power applications in which the inverters have to inject unbalanced and/or harmonic voltage or current or both for neutralizing voltage or current imbalance or harmonics. The proposed controller design is tested on three different compensating type custom power devices: the Distribution Static Compensator (DSTATCOM), the Dynamic Voltage Restorer (DVR) and the Unified Power Quality Conditioner (UPQC). The simulations have been carried out using PSCAD/EMTDC.