Energy storage with batteries are critical systems in isolated microgrids. Charging depends on the manufacturing technology and methodology, and must be controlled depending on the voltage, current, and considering state of charge of the batteries, the power sources, and the load. In this work, a control for a dispatchable power source connected to the distribution network for charging battery banks in isolated microgrid is proposed, considering the dynamics of a distributed generation system with diesel generator set (DGS) and a grid tie converter. This control was implemented through a PAC (Programmable Automation Controller), considering two main charging approaches: a) a full battery bank charging, made when the battery state of charging reach the minimum permitted level, and b) a partial battery bank charging, made when the 90% of the maximum state of charging is not reached in the day. A real and consolidated system was used as a case study: this system is the isolated microgrid with generation distributed in Ilha Grande, northeastern Brazil.
Multilevel inverters are attractive solutions for medium-voltage and high-power applications. Topologies with five steps can produce better quality voltage output than the conventional ones with three steps. This paper presents a simple methodology to systematically derive five-level hybrid voltage source converters. Among the six topologies obtained, two are novelties. A brief analysis and a comparative study show that at least one of the new topologies has acceptable performance in terms of losses, thermal stress, and voltage stress.
In this paper is proposed a high gain hybrid DC-DC converter applied to photovoltaic systems. The proposed converter is based on boost converter integrated to cells of a switched capacitor with the addition of a small resonant inductor. This proposal has shown advantages such as extended static gain, reduction of voltage stress in the semiconductors and reduction of current peaks in switches. A 200 W prototype has been assembled and the results are presented. A maximum yield of 97.1 % was obtained for a voltage gain of 10.
This paper addresses the control design of a current mode control for a three-phase voltage source converter. A variant of the Active Disturbance Rejection Control (ADRC) scheme is proposed for comparison with the classical inner control approach. The ADRC method has a straightforward design procedure and has well-known abilities for disturbance rejection and robustness to parametric uncertainties of the system. Theoretical studies are presented and simulation results are discussed by using EMTP-RV environment considering the system Synchronous Reference Frame Control, whose modeling was extracted from the analysis performed in a classical refer-ence.
This paper proposes a dynamic modeling and con-trol design for a electromagnetic frequency regulator (EFR) that can be applied to distributed generation (DG) systems based on renewable energy sources (RES). The system controllers parameters are designed by using root-locus method (RLM) in order to realize desired dynamic performance. Besides, a stability analysis for closed-loop system is assessed...
