Sensorless Current Control of Three-Phase Inverter-Based Distributed Generation

This paper presents a modified adaptive Kalman filter for sensorless current control of a three-phase inverter-based distributed generation system. Measurement and digital signal processor delays have been compensated by using a modified Kalman filter. The control variable states can be estimated one sample in advance with a reduced number of sensors. Two current control loops with the steepest descent adaptive control for grid voltage estimation have been employed to boost robustness. Stability and dynamic performance have been examined for different state variables using root locus. Simulation and experimental results validate the proposed control approach.