Contents I. Introduction
Recently, benefits such as low voltage stress, low total harmonic distortion, low power loss, high output waveform quality, reduced electromagnetic interference, and so on, have attracted industry attention to multilevel inverters [1]–[2]. These converters can be applied in solar cell, fuel cell or wind turbine applications [3]. Generally, multilevel converters are divided into three categories: 1. Diode clamped or neutral point clamped (NPC) 2. Flying capacitor (FC) and 3. Cascaded multilevel inverter (CMLI) [4]–[6]. Capacitors voltage balancing is the most important issue in NPC and FC converters, while CMLI converters require a large number of sources to have numerous voltage levels [7]–[8]. Therefore, the main aim of CMLIs is to propose configurations that are capable of generating the highest number of levels with the least number of devices [9]–[11]. Based on abovementioned problems, the researchers have focused on switched-capacitor based MLIs [12], [13]. These converters use fewer sources, which leads to reduced volume, weight, and cost [14]–[15]. Also, the voltage balancing problem of capacitors has been solved in these converters. Switched-capacitor based MLIs are divided into two categories: high gain [14]–[16] and unity gain [17]–[18] converters. A new switch ladder modified H-bridge multilevel inverter (SLMHB-MLI) has been suggested in [19], where fewer switches, natural voltage balancing of capacitors and boosting ability are the main advantages. In contrast, numerous diodes is the main drawback that results in reduced efficiency. Boosting ability and self-voltage balancing of capacitors in [20], [21] and generating negative steps without H-bridge in [2] are the major advantages. Whereas, numerous MOSFETs is disadvantage of [20], [21]. Also, high total standing voltage (TSV) on switches and high number of DC sources are shortcomings of [2]. A new asymmetric switched-capacitor MLI has been proposed in [22] that benefits from reduced switches/drivers. But, the high TSV on switches and numerous diodes are disadvantages that lead to decreased efficiency. In [23] a new single-phase hybrid MLI with boosting ability has been presented. The large number of components required for producing 9 steps is the main disadvantage. The [24] has presented a new switched-capacitor MLI module with merits of boosting ability, natural voltage balancing of capacitors and intrinsic generation of negative steps. On the other hand, numerous devices required for increased steps and high TSV on switches are major drawbacks.
