This study presents a new software-based plug-in dead-time compensator for grid-connected pulsewidth modulated voltage-source inverters of single-stage photovoltaic (PV) systems using predictive current controllers (PCCs) to regulate phase currents. First, a nonlinear dead-time disturbance model is reviewed, which is then used for the generation of a feed-forward compensation signal that eliminates the current distortion associated with current clamping effects around zero-current crossing points. A novel closed-loop adaptive adjustment scheme is proposed for fine tuning in real time the compensation model parameters, thereby ensuring accurate results even under the highly varying operating conditions typically found in PV systems due to insolation, temperature, and shadowing effects, among others. The algorithm implementation is straightforward and computationally efficient, and can be easily attached to an existent PCC to enhance its dead-time rejection capability without modifying its internal structure. Experimental results with a 5-kW PV system prototype are presented.

In this paper, an inverter-side current (ISC) control strategy for grid-connected voltage source inverter with LCL filters is proposed based on a generalized predictive control (GPC) formulation as it has the advantages of fixed switching frequency, a systematic design procedure and low computational complexity. As the GPC strategy is a subtype of continuous-control-set model predictive control strategies, a proper model for controlling the ISC is obtained, showing that a full-order model is preferred to its first-order counterpart. The controller is designed taking into consideration harmonic distortion limits and robustness against filter component variations. To this end, a complete three-wire LCL filter model is obtained and impedance sensitivity to each component variation is analyzed. Finally, its performance is evaluated by means of experimental results and compared with a predictive deadbeat controller.

This work focuses on the control of instantaneous complex power of a grid-connected VSI. In this work, a new space vector modulation based direct power control approach is proposed: the Robust Predictive Direct Power Control (RP-DPC). The proposed predictive control algorithm ensures that both, instantaneous real and imaginary powers track the reference with high speed and accuracy reducing steady-state errors. In order to reduce the Total Harmonic Distortion (THD) in the output currents, a Fundamental Frequency Positive Sequence detector is used in conjunction with a prediction Grid Voltage Observer. Comparative simulations and experimental results of a 10 kW three-phase grid-connected VSI showing the steady-state and transient performance of the proposed RP-DPC are given. A low THD and balanced output currents are maintained even under Severe Voltage Unbalance conditions.