Control Scheme for a Single-Phase Grid-Tied Voltage Source Converter With Reduced Number of Sensors

This paper proposes a grid voltage sensorless controller for single-phase voltage source converters. The controller is composed of an observer and a current control scheme. The proposed observer replaces the grid voltage measurement and is used to generate the current references and to compensate the perturbation effect of the actual grid voltage on the coupling inductor. This allows us to implement a simple proportional resonant current control algorithm. The proposed observer also estimates the grid frequency, allowing us to immunize the controller to grid frequency variations.