Review on Single-DC-Source Multilevel Inverters: Voltage Balancing and Control Techniques

Nowadays, single-dc-source multilevel inverter (SDCS-MLI) topologies are being considered as more suitable for many power system applications such as renewable energy conversion systems and electrified transportations compared to the multiple-dc-source MLIs. Voltage balancing of the auxiliary capacitors in those configurations is a major matter of concern. Different techniques have been developed to overcome this issue that can be mainly categorized as internal controller-based and external controller-based techniques. In the former techniques, the redundant switching states help balancing the capacitors voltages. On the other hand, the latter techniques involve external regulators to balance the capacitors’ voltages. This article analyzes most of the existing techniques to control and balance the capacitors voltages in SDCS-MLIs, such as pulsewidth modulation, space vector modulation (SVM), hysteresis control, model predictive control, sliding mode, and artificial intelligence based control techniques. Furthermore, a comprehensive comparison is presented to illustrate the advantages/disadvantages of each technique. Finally, some industrial challenges and future works are projected.