In a PV-dominant DC microgrid, the traditional energy distribution method based on the droop control method has problems such as output voltage drop, insufficient power distribution accuracy, etc. Meanwhile, different battery energy storage units usually have different parameters when the system is running. Therefore, this paper proposes an improved control method that introduces a reference current correction factor, and a weighted calculation method for load power distribution based on the parameters of battery energy storage units is proposed to achieve weighted allocation of load power. In addition, considering the variation of bus voltage at the time of load mutation, voltage secondary control is added to realize dynamic adjustment of DC bus voltage fluctuation. The proposed method can achieve balance and stable operation of energy storage units. The simulation results verified the effectiveness and stability of the proposed control strategy.

The internal forces in stiffeningwalls are usually determining by numerical methods. Extreme values of forces and displacements can be achieved without significant problems. The numerical model is always labour-intensive; therefore, it is not used for single-family or multi-family buildings with a simple wall layout. To calculate efficiently internal forces in such walls uses an analytical model. Eurocode 6 (prEN 1996-1-1: 2019) does not provide specific guidelines for determining geometrical characteristics and procedures for calculating the values of internal forces in the stiffening walls. The use of numerical methods and other reliable methods was allowed. The paper presents the adaptation of the total stiffness method to determine internal forces in a building with a simple wall system. The method was based on dividing the masonry wall with openings into pillars, lintels, bottom sprandels and flanged walls. The analytical results were compared with linear-elastic FEM calculations. It has been demonstrated that flexural stiffness, shear stiffness and localization of rotation centre (RC) had a crucial impact on masonry structure.

One of the most important aims of the sizing and allocation of distributed generators (DGs) in power systems is to achieve the highest feasible efficiency and performance by using the least number of DGs. Considering the use of two DGs in comparison to a single DG significantly increases the degree of freedom in designing the power system. In this paper, the optimal placement and sizing of two DGs in the standard IEEE 33-bus network have been investigated with three objective functions which are the reduction of network losses, the improvement of voltage profiles, and cost reduction. In this way, by using the backward-forward load distribution, the load distribution is performed on the 33-bus network with the power summation method to obtain the total system losses and the average bus voltage. Then, using the iterative search algorithm and considering problem constraints, placement and sizing are done for two DGs to obtain all the possible answers and next, among these answers three answers are extracted as the best answers through three methods of fuzzy logic, the weighted sum, and the shortest distance from the origin. Also, using the multi-objective non-dominated sorting genetic algorithm II (NSGA-II) and setting the algorithm parameters, thirty-six Pareto fronts are obtained and from each Pareto front, with the help of three methods of fuzzy logic, weighted sum, and the shortest distance from the origin, three answers are extracted as the best answers. Finally, the answer which shows the least difference among the responses of the iterative search algorithm is selected as the best answer. The simulation results verify the performance and efficiency of the proposed method.