ВИЗНАЧЕННЯ ПАРАМЕТРІВ ФОТОЕЛЕКТРИЧНОЇ СИСТЕМИ З АКУМУЛЯТОРОМ ДЛЯ ПОТРЕБ ЛОКАЛЬНОГО ОБ’ЄКТУ

Purpose. Improving the methodology for determining the parameters of a photoelectric system with a battery for the needs of a local object using archival data of the generation of a photoelectric battery with planning the cost of energy consumption from the network for all seasons of the year.Methodology. Using an archive of data on the power generation of a photoelectric battery and analysis of energy processes in a photoelectric system with a battery using computer simulation.Findings. Calculated according to the archive data for five years, the average monthly values of photoelectric battery generation power for time intervals during the day determined according to tariff zones. Dependencies to determine the recommended average value load power of a local object at time intervals.Originality. It is proposed to determine the base schedule of the local facility and the parameters of the photoelectric system based on the average monthly values of photoelectric battery generation in the transition seasons – October, March and the expected cost of energy consumed from the grid during the year. The recalculation of the base value of power during the year is substantiated taking into account the duration of daylight. A method for determining the recommended load schedule of a local object with the formation of the battery charge according to the average monthly value of the photoelectric battery generation power at time intervals during the day, which are determined by archival data for the object location.Practical value. The obtained solutions are the basis for designing photoelectric systems with a battery to meet the needs of local objects.

Hierarchical Control Strategy for Microgrid Based on Finite-time Consensus Algorithm

In order to overcome the shortcomings of centralized control strategy for microgrid, a hierarchical control strategy based on finite-time consensus algorithm is proposed in this paper. Based on the droop control, the control strategy uses the finite-time consensus theory of multi-gent system to solve the optimal power generation value of the system, and adjusts the droop coefficient to make the power generation power of the power supply the optimal value. Then the compensation of frequency and voltage is introduced by multi-agent technology to stabilize the system frequency and voltage at rated value.

Matryoshka phonon twinning in α-GaN

Understanding lattice dynamics is crucial for effective thermal management in electronic devices because phonons dominate thermal transport in most semiconductors. α-GaN has become a focus of interest as one of the most important third-generation power semiconductors, however, the knowledge on its phonon dynamics remains limited. Here we show a Matryoshka phonon dispersion of α-GaN with the complementary inelastic X-ray and neutron scattering techniques and the first-principles calculations. Such Matryoshka twinning throughout the basal plane of the reciprocal space is demonstrated to amplify the anharmonicity of the related phonons through creating abundant three-phonon scattering channels and cutting the lifetime of affected modes by more than 50%. Such phonon topology contributes to reducing the in-plane thermal transport, thus the anisotropic thermal conductivity of α-GaN. The results not only have implications for engineering the thermal performance of α-GaN, but also offer valuable insights on the role of anomalous phonon topology in thermal transport of other technically semiconductors.

Modeling and control of a hybrid DC/DC/AC converter to transfer power under different power management strategies

<span>A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this<br />scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.</span>