With the advancement of aircraft electrification, the demand for electrical power has increased significantly. Consequently, intensifying challenges in power systems design—particularly in high-voltage distribution systems. The sizing of voltage levels and the optimization of weight play a crucial role in determining overall aircraft weight, directly impacting performance. This paper proposes a voltage level optimization design method for aircraft power distribution system that minimizes system weight while adhering to thermal and insulation constraints. An optimization model is constructed and solved using a multidisciplinary modeling approach. The method is validated and evaluated with parameters from aircraft of different scales, and the optimization results are analyzed.

This paper offers a comparative analysis of Maximum Power Point Tracking (MPPTs) techniques under the spinning conditions for small satellite applications. The Nano Satellite (NanoSat) is constrained on volume and mass with body-mounted solar panels and where it is dedicated to some special orientation scenarios, depending on specific mission requirements. This results in irregular solar irradiance on the PV system; thus, it needs an efficient and effective strategy to extract the maximum power transferred to the loads in the NanoSat Electrical Power System (EPS). While the EPS can be regarded a space microgrid due to control and coordination in a small electric network of distributed generations (DGs), storage, and loads. Therefore, some well-known MPPT techniques are investigated where different scenarios are carried out among conventional Perturb and Observe (P&O), Incremental Conductance (IC), and Ripple Correlation Control (RCC) to highlight the optimal MPPT extractions for NanoSat applications. The system was developed and modeled in MATLAB/SIMULINK and the final findings demonstrate that the RCC provides smooth power compared to other ones, while the other ones offer an oscillated power under the effect of radiations change and spinning conditions for the system under test.

The virtual synchronous generator (VSG) has been extensively applied for the integration of distributed generators. For the benefit of analysis, both the reduced-order small-signal model (RSM) and full-order small-signal model (FSM) have been proposed; however, because of the different modeling approaches, the modeling accuracy may differ a lot. To provide a guideline for selecting a suitable model, an accuracy assessment has been conducted in this paper, where different grid strength cases and equilibrium points are considered. More specific, the eigenvalue analysis is adopted for comparing the dominant dynamics of the RSM and FSM. Afterwards, the responses of the RSM and FSM are compared with the nonlinear model (NM) in the Digsilent/Powerfactory to show the modeling accuracy. It has been found that the RSM is mainly suitable for the weak and relatively strong grids, while the FSM shows better accuracy in the case of an extremely strong grid and around the equilibrium point that is close to VSG's rated output.

Unbalanced voltages in three-phase power systems is a common perturbation propagated along the grid. Distributed Generation plants have gained widespread attention due to their capability to improve power quality in a distributed manner, including voltage unbalance mitigation. A conventional control strategy to command power plants during balanced grid voltages, is the use of power factor to inject/absorb reactive power depending on grid conditions. Advanced control strategies during unbalanced grid voltages can be selected prioritizing positive or negative sequence active and reactive power. This selection determines the voltage support service and therefore can improve the voltage profile, i.e. phase-voltages can be properly supported and voltage imbalance simultaneously corrected. Based on the definition of effective power factor in IEEE 1459 Standard, the reactive power needed for any control strategy is obtained and the resulting effects are described.

This paper proposes a new active damping method based on virtual resistors for three-phase grid connected voltage source inverters (VSI) with LCL filter. The use of this filters is a standard solution to provide the proper attenuation to the sideband voltage harmonics of the modulation signal. However these grid filters can introduce an unstable dynamics if a passive or active damping is not properly introduced. The passive damping solution causes a decrease of the overall efficiency due to the associated losses and reduces the filter effectiveness but in contrast no more extra sensors are needed. Active damping methods are more efficient because they don't introduce losses but suffers from control and system complexity because in some cases a high number of sensors are needed. The proposed strategy employs a nonlinear sliding mode control (SMC) scheme in natural frame in combination with a Kalman filter to emulate a resistor in the LCL filter which damps the system actively without the use of extra sensors. Two current controllers are designed in order to control the active and reactive power independently and a voltage controller is designed to control the neutral point which is fixed with a third harmonic voltage in order to increase the control dynamic range.

Grid faults are one of the most severe perturbations to deal with in grid connected systems. To support the grid under voltage-sags (dips), different reactive power control strategies are needed depending on the type of grid fault. One of the possible objectives when supporting the grid voltage under type C voltage sags could be to avoid undervoltage in the faulted phases and over-voltage in the non-faulted phase. Therefore, the fault can ride-through the perturbation and the system disconnection can be avoided. This may be accomplished by injecting positive sequence reactive power to raise the voltages and negative sequence reactive power to equalize them. In this work, a detailed mathematical description is introduced to limit the voltage in the phase that do not suffers the voltage-sag just below over-voltage limit, while increasing as much as possible the other two faulted phases. This voltage support service is limited by the maximum rated current. Selected simulation results are provided to understand the proposed reactive power control during type C voltage-sags.