This paper presents a new predictive control algorithm for grid-connected current-controlled inverters. The control combines a two-sample deadbeat control law with a Luenberger observer to estimate the future value of the grid currents. The resulting control offers robustness against the computational delay inherent in the digital implementation and considerably enhances the gain and phase margins of the previous predictive controls while maintaining the high-speed response typical of the deadbeat controllers.

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.

This work proposes a linear generalized predictive current control (GPCC) for grid-connected voltage-source inverters, which presents a fast response to current reference step changes, parameter variation robustness, and low distortion at the output currents, with reduced computational effort. Experimental results on a 10-kW converter connected to a real grid are shown, and the proposed controller is compared against a classical proportional resonant controller.

The design and implementation of a novel method for reference generation that is applied to active power Alters (APFs) is introduced in this paper. The proposed reference generation performs harmonic detection based on the Goertzel algorithm. The method computes both the module I₁ and the phase phi of the signal, with minimum computation overhead. This makes the method suitable for APFs or other applications that require harmonic detection. A comparison analysis between the discrete Fourier transform and the proposed method is carried out. The proposed reference generator is implemented using a digital signal processor and tested with waveforms from typical load currents. Experimental results are obtained under both stationary and transient states.

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 study focuses on the control of instantaneous complex power of a grid-connected voltage-source inverter (VSI). In this study, 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.