Finite Control Set–Model Predictive Control with Modulation to Mitigate Harmonic Component in Output Current for a Grid-Connected Inverter under Distorted Grid Conditions

Abstract

Similar to the scheme in [19], the proposed scheme introduces weighting factors that are duty ratios of each individual active vector. Since each space vector is active for a certain duty interval during the sampling period, these duty ratios are chosen as the weighting factors for the corresponding vectors. Based on these values, the cost functions for each pair of the active voltage vectors are calculated as follows: Since each vector is applied for duty intervals d1 and d2 , respectively, these duty intervals are used as the weighting factors to evaluate the effect of each vector in the final cost function in Equation (45). Harmonic Mitigation and MAF-PLL The purpose of the proposed scheme is to minimize the error between the reference currents and predicted ones by using the cost functions in Equations (43)–(45). Since the proposed scheme is designed in the stationary reference frame, the stationary reference currents without harmonic distortion are required for the proposed scheme to work successfully with the high quality of inverter output currents. Figure 12 shows the improvement of the transient response through a modification of the proposed FCS-MPC scheme. Because the slow transient is mainly due to the adoption of the MAF, the modified method works with the FCS-MPC scheme and conventional SRF-PLL at start-up instant.