The implementation of a dual electric system that is capable of operating with either constant current and variable voltage, or constant voltage and variable current appliances, is one of the possible options to solve low-intensity stochastic energy utilization problems from renewable energy sources. This research paper analyzes the potential benefit of a novel three-phase dual system power inverter over the conventional inverter used in a solar power plant. The concept of such a power inverter is explained, and the digital twin model is created in a MATLAB Simulink environment. The efficiency characteristic of the simulated inverter is compared to the efficiency characteristic of a real conventional inverter. A standalone data logging system and an additional data acquisition system were used to collect and process data from the real inverter. Comparison of the digital twin inverter and the real conventional inverter shows the potential benefit of this novel inverter technology. It is shown that the novel inverter can operate in a wider range of DC input power. The potential economic benefit is also presented and discussed in the paper.

Renewable energy implementation in residential-scale grid-connected systems is already popular, and the growth of such systems is increasing every year. Grid-connected solar systems are relatively simple to install and operate; in addition, such power plants are relatively inexpensive compared to other renewable sources and grid-connection options. However, most residential grid-connected system owners believe that they will become independent from a distribution system operator (DSO) once a renewable energy source (RES) becomes available. As a rule, after installation, without DSOs, grid-connected systems are typically shut down due to a faulty grid, despite RES availability; therefore, such RES grid-connected system owners at later phases aim to become at least partially independent of DSOs. After such a change, the importance of developing a grid-tied inverter connection to an off-grid system will increase. While developing such a system connection the main issue analyzed in this paper is to control the excess power without affecting the accumulated energy levels in a system. As a result, a solution for such a system structure is presented with its main advantage to control excess power without affecting the accumulated energy level.

Households with photovoltaic installations contribute to reducing greenhouse gas emissions and mitigating global climate change. To fully utilize the benefits of clean solar energy, it is essential to ensure its efficient use, which can be achieved by consuming all generated energy locally, within the household or a microgrid community, eliminating wastage during the grid transportation and storage. In this work, we propose a method to enhance self-consumption by eliminating simultaneous bidirectional energy flow in the phase lines of a three-phase grid-tied household system, particularly in cases of significant load asymmetry. We developed an adaptive power flow management (APFM) algorithm which distributes solar-generated energy across the household grid’s phase lines based on their respective loads and solar power generation level. A simulation based on real-world data demonstrated that the APFM algorithm both eliminates simultaneous active power import and export flows and ensures that all power exported from the household to the DSO grid remains symmetrical across all phase lines. As observed from the simulation results, applying the APFM algorithm reduced the daily imported and exported energy between the household and the DSO grid by an average of 27.5% during the spring–autumn period for a specific household. Additionally, reducing energy flow led to a 5% average increase in self-consumption within the household grid, with peak improvements reaching 16.5%.

In this study, we investigate the impact of electric energy storage (EES) on phase line power flow symmetry and photovoltaic (PV) energy utilization in prosumer three-phase four-wire integrated household systems. The analysis is based on high-time-resolution (1 s) experimental data collected from a real household grid and subsequent simulations of energy flows using MATLAB/Simulink software. Two converter operation strategies were evaluated: the conventional symmetric mode and the asymmetric mode developed by the authors based on an adaptive power flow management algorithm. For both strategies, the impact of EES capacity on imbalance in the distribution system operator (DSO) grid was investigated. The methodology analyzes energy flows in each phase line separately, allowing for a detailed assessment of the imbalance between phase line phenomena and their impact on local energy consumption. Key performance parameters used for the efficiency evaluation include the self-consumption and self-sufficiency rates, which quantify the share of locally generated energy consumed within the household and the degree of independence from the DSO grid. The results show that combining adaptive asymmetric inverter control with appropriately sized energy storage allows for more efficient on-site utilization of PV energy, which, at the same time, improves the load symmetry of the phase lines in the DSO grid.