**5. Conclusions**

A three-phase hybrid cascaded MLI configuration for APF applications has been proposed in this paper. The proposed configuration conjoins the cascaded H-bridge MLI configuration and the three-phase cascaded VSI configuration via OEWs. This topology uses fewer switches than typical MLI topologies while improving the voltage levels of the proposed MLI. Twenty-two voltage levels are generated per phase from this topology by using only 42 switches. Table 4 shows a comparison of the proposed topologies with the conventional MLI topologies to produce 21 voltage levels (one level lower than the number of levels generated by the proposed topology). The proposed topologies have fewer switches than the prior art MLI topologies. The modularity of the proposed topologies is higher and the proposed topologies have fewer DC-link capacitors than other MLI topologies. For a comparison of conduction, the voltage and current stresses of the other topologies were then compared using the same number of switches as in the proposed topology. A control scheme was proposed to execute the proposed topology for APF application. The proposed MLI-based APF was used to compensate the harmonic load currents while the grid supplied the fundamental positive-sequence currents of the load. The proposed APF topology was simulated by using the SIMULINK environment. The nonlinear load was implemented by using a three-phase diode bridge circuit connected to the resistive inductive loads. To validate the good performance of the proposed MLI and the accuracy of the control, the MLI was built in a lab, and the generated switching pulses were implemented on the MicroLabBox data acquisition system and fired into the IGBTs through gate drives. The proposed topology and its related proposed control scheme were experimentally tested for the use for a PV–grid connection and for APF applications. The simulation and the experimental results show that the proposed APF is functions well in eliminating the unwanted harmonics generated by the nonlinear load. The THD of the line currents was within the acceptable limits as defined by IEEE-519 standard.


**Table 4.** Comparison results.

**Author Contributions:** Conceptualization, A.M.N. and A.A.A.-S.; Data curation, A.M.N. and A.A.; Formal analysis, A.M.N. and A.A.A.-S.; Funding acquisition, A.M.N. and A.A.; Investigation, A.A.A.- S. and K.E.A.; Methodology, A.M.N. and A.A.A.-S.; Project administration, A.A. and K.E.A.; Software, A.M.N., A.A., A.A.A.-S. and K.E.A.; Supervision, A.A. and K.E.A.; Writing—original draft, A.M.N. and A.A.A.-S.; Writing—review & editing, A.M.N. and A.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Informed Consent Statement:** Not applicable.

**Acknowledgments:** This work was supported by the National Plan for Science, Technology, and Innovation, King Abdulaziz City for Science and Technology, Kingdom of Saudi Arabia, Award Number (13-ENE1157-02).

**Conflicts of Interest:** The authors declare no conflict of interest.
