This paper presents the implementation of a single-controllable microgrid in the engineering school of the Federal University of Minas Gerais using commercial devices. Such a microgrid exchanges controllable active and reactive power terms with the upstream grid, proportionally shares active/reactive power among the battery-based DERs and endows the microgrid with the capability of operating in both grid-connected and islanded modes. The energy storage system is composed of three different battery technologies: lead-acid, lithium-ion and sodium–nickel, which are coordinately controlled according to their inherent features. A usable average energy control is proposed to avoid mismatches between the batteries’ states of charge. The single-controllable microgrid performs the following services: self-consumption, energy time shift, peak-shaving and reactive power support to the upstream grid. The coordinated secondary control and the operating modes of the microgrid were validated by means of full-scale experimental results using commercial devices. The lithium-ion battery showed the best performance in terms of round-trip efficiency, 93% over 85% (lead-acid) and 81% (sodium–nickel). The results demonstrated the microgrid’s capability of delivering ancillary services at the connection with the upstream grid, and proportionally exploiting the dispersed battery banks. In addition, the challenges of practical implementation were analyzed.

The grid-forming converter that supplies voltage magnitude and frequency is a key element for isolated remote communities, and then wear-out analysis is an essential figure of merit. Therefore, this paper proposes the two-phase three-wire (2Φ3W) grid forming converter applied in a case study of isolated riverside communities in the Brazilian Amazon region. The proposed xyn-converter displaces the voltage line angle in 180aaaaaaaaaaaaaaaaaaaaaa, differing from αβn-converter and abn-converter that displace voltage line angle in 90° and 120° respectively. First, the authors have also proposed a semiconductor current stress evaluation for 2Φ3W converters comparing the RMS current. Then, the lifetime evaluation of the three evaluated grid-forming converters is conducted. The results show that the converter operating in the xynconverter presents the highest reliability among the three converters. Finally, the thermal stress analysis is validated by means of a 2Φ3W converter prototype with an open semiconductor module. For the evaluated converters, the xyn-converter has the least thermal stress for balanced and unbalanced load conditions and therefore the longest lifespan. The experimental validation shows that the average temperature of the xynconverter is 19.4% and 23.3% lower than both the abn-converter and the αβn-converter under balanced load conditions.

The growing integration of power electronics in industrial systems has led to the widespread adoption of variable frequency drives, most of which are powered by 6-pulse diode bridge rectifiers combined with large DC-link capacitors. While this configuration ensures a stable voltage supply for IGBT-based motor drives, it also behaves as a non-linear voltage-source load that injects substantial harmonic distortion into the grid. Conventional mitigation strategies often involve shunt active power filters (SAPFs), but when improperly dimensioned, these filters can end up requiring power ratings nearly as large as the load itself—rendering them impractical for many applications. This paper introduces a streamlined design approach aimed at minimizing the size and rating of SAPFs and associated passive elements for typical rectifier-capacitor-fed induction motor systems. A key part of this approach is the use of one-cycle power components, based on Conservative Power Theory (CPT), both in the filter design and its control. The effectiveness of the proposed strategy is demonstrated through comprehensive PLECS simulations and real-time hardware-in-the-loop experiments. The results demonstrate the effectiveness of the proposed approach. By selecting a load impedance value of 4.5%,which is lower than the 6% commonly recommended in the literature, good performance is achieved in terms of low harmonic distortion and reduced current ripple in the grid current.