Abstract-Multilevel converters are a very interesting alternative for medium and high power drives. One of the more flexible topologies of this type is the Multicell converter. This paper presents a new regenerative cell suitable for cascaded multilevel inverters. The cell uses a reduced singlephase active rectifier at the input and an H-bridge inverter at the output side. The cell has a reduced switch count and presents a very good performance, controlling effectively the waveform of the input current and of the output voltage.The results presented in this paper confirm that this medium voltage inverter effectively eliminates low frequency input current harmonics at primary side of the transformer and operates without problem in regenerative mode.

The Magellan Telescope Adaptive Optics System (MagAO) is subject to resonance effects induced by elements within the system instrumentation, such as fans and cooling pumps. Normalized PSDs are obtained through frequency-based analysis of closed-loop on-sky data, detecting and measuring vibration effects. Subsequently, a space-state model for the AO loop is obtained, using a standard AO loop scheme with an integrator-based controller and including the vibration effects as disturbances. Finally, a new control alternative is proposed, focusing on residual phase variance minimization through the design and simulation of an optimal LQG control approach.

The use of renewable energies sources is taking great importance due to the high demand for electricity and the decrease in the use of fossil fuels worldwide. In this context, electricity generation through photovoltaic panels is gaining a lot of interest due to the reduction in installation costs and the rapid advance of the development of new technologies. To minimize or reduce the negative impact of partial shading or mismatches of photovoltaic panels, many researchers have proposed four configurations that depend on the power ranges and the application. The microinverter is a promising solution in photovoltaic systems, due to its high efficiency of Maximum Power Point Tracking and high flexibility. However, there are several challenges to improve microinverter’s reliability and conversion efficiency that depend on the proper control design and the power converter design. This paper presents a review of different control strategies in microinverters for different applications. The control strategies are described and compared based on stability, dynamic response, topologies, and control objectives. One of the most important results showed that there is little research regarding the stability and robustness analysis of the reviewed control strategies.

The control in an inverter system for photovoltaic applications is important as it can impact on the efficiency of the system. In this paper a review of the main control strategies used in photovoltaic systems is presented. The study is divided into two branches: grid connected systems and off-grid systems. The paper includes a review of strategies common to both types of systems, including a comparison of both linear and non-linear control strategies. In addition, the implementation of an MPPT algorithm which gives an increase in the efficiency of the generation systems is described. Although there is a large variety of control strategies, there are some that offer better results, from both point of view the computational consumption and the system efficiency, these differences are identified in the presented results.

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