In this paper, a step-up DC-DC multi-output converter is introduced by integrating a super-lift Luo converter, flyback topology, and coupled inductor concept. The proposed multi-output converter has positive output super-lift structure while simultaneously generating step-up voltages in its outputs. The proposed step-up converter has two non-isolated and one isolated output with a simple structure using one switch and one magnetic core. There is no voltage spike by the leakage inductance of the coupled inductor across the switch in the proposed converter. Therefore, the switch has low-stress voltage. The energy in the leakage inductor is recycled leading to higher efficiency in comparison to similar converters with the coupled inductor. The operating principles and the characteristics of the proposed converter are analyzed and discussed. The experimental results of 110W prototype verify the theoretical analysis and the benefits of the proposed converter in comparison to similar multi-output converters. The conducted electromagnetic interference evaluation of the proposed converter is presented and it is reduced using a common-mode choke.

An efficient and most famous tool to enhance damping of the power system low frequency oscillations is the conventional widely used lead-lag Power System Stabilizer (PSS). To achieve the desired level of robust performance under transient situation, selecting a suitable design method for optimal tuning of PSS parameters is very important in multi-machine power system. Because, it is a multimodal and difficult combinatorial optimization problem, this paper presents a novel parameter automation strategy for Particle Swarm Optimization (PSO) called PSO with Time-Varying Acceleration Coefficients (PSO-TVAC). This optimization method has a strong ability to successfully control both global and local search in each iteration process for considerably increasing the probability of finding the global optimum solution. The PSO-TVAC algorithm is applied to optimal tuning PSS parameters problem in order to reduce the PSS design effort and find the best possible solution within a reasonable computation time. For this reason, the robustly selection of PSSs parameters is converted as an optimization problem based on the time domain-based objective function under different operating conditions. The robustness of the proposed method is demonstrated on a multi-machine power system in comparison with the classical PSO and conventional method based designed PSSs. It is shown through the nonlinear time domain simulation and some performance indices for a wide range of loading condition. The analysis of the results shows that the improved PSO-TVAC is not only very effective but also provides an excellent ability for damping low frequency oscillations and greatly enhance the dynamic stability of the power system. Moreover, the proposed PSO-TVAC algorithm is superior than that of the classical PSO one in terms of accuracy, convergence and computational effort.