Sensorless Virtual-Flux Based Predictive Direct Power Control of Three-Phase PWM Rectifiers

New sensorless virtual-flux (VF) based predictive direct power control (PDPC) (VF-PDPC) of a three-phase pulse width modulation (PWM) rectifier is developed in this paper. The VF estimation is achieved through a simple neural filter based integrator (NF-I) in series with a multi-output adaptive linear neuron (MO-ADALINE). The NF-I leads to cancel dc offset and harmonic distortions in the estimated VF. Thereafter, positive sequence components of the VF are extracted by mean of a MO-ADALINE. The estimated VF is then used for robust sensorless VF-PDPC with a constant switching frequency and tested through numerical simulations. Simulation results illustrated superiority of the proposed sensorless VF-PDPC compared with the conventional PDPC under ideal and non-ideal grid conditions. The proposed sensorless control strategy achieved good stability and the grid currents are quasi-sinusoidal, even if the grid voltages are highly unbalanced and distorted.