Robust and Intelligent Control for Single-stage Grid-Connected Modular Multilevel Converter in PV Applications

Fault‐tolerant modular multilevel converter for a seamless transition between stand‐alone and grid‐connected microgrid

“…The proposed MMC topology model is depicted in Figure 2. As voiced in our previous work [5], MMC equivalent circuits are composed chiefly of the AC and DC paths. The AC path adjusts the currents of the converter, while the DC path limits the internal circulating currents of the MMC.…”

“…The first variable could be PV constant current voltage or the active power ( P ), while the second variable can be the reactive power ( Q ). The most effective way to control the operation of the system is to calculate the i d and i q flow into the grid, defined by (– 6) [5]. The outputs of the external control loops are the current grid references in d–q axes, $${i}_{{\rm{d}}\_{\rm{ref}}}$$ and $${i}_{{\rm{q}}\_{\rm{ref}}}$$.…”

“…Efficiency is lessened due to using the two-stage power conversion. As a result, two-level and/or three-level inverters frequently fail to fulfill harmonic standards [5]. Therefore, an extensive and costly filter increases cost and complexity.…”

“…As a result, the MMC performs at a low switching frequency, strengthening operational efficiency. Furthermore, the stepped output voltage empowers low-voltage switches [5].…”

Neutral Voltage Modulation for Maximizing the Linear Modulation Region and Limp-Home Mode Operation of Multilevel Cascaded Inverters Under DC-Link Imbalance Conditions

“…MLIs are also attractive for high voltage applications, because they can be constructed by stacking low voltage modules [2,[4][5][6]. From the reasons above, MLIs are utilized in various industrial applications such as static synchronous compensators, battery energy storage systems, power plants, and so on [7][8][9][10]. The topologies of MLIs can be roughly categorized as neutral point clamped and cascaded types [11,12].…”