This paper presents a new approach for coordinated design of power system stabilizers (PSSs) and static VAR compensator (SVC)-based controller. For this purpose, the design problem is considered as an optimization problem whose decision variables are the controllers’ parameters. Due to nonlinearities of large, interconnected power systems, methods capable of handling any nonlinearity of power networks are mostly preferable. In this regard, a nonlinear time domain based objective function is used. Then, the coyote optimization algorithm (COA) is employed for solving this optimization problem. In order to ensure the robustness and performance of the proposed controller (COA-PSS&SVC), the objective function is evaluated for various extreme loading conditions and system configurations. To show the contribution of the coordinated controllers on the improvement of the system stability, PSSs and SVC are optimally designed in individual and coordinated manners. Moreover, the effectiveness of the COA-PSS&SVC is assessed through comparison with other controllers. Nonlinear time domain simulation shows the superiority of the proposed controller and its ability in providing efficient damping of electromechanical oscillations.

This paper introduces three topologies of a non-isolated high gain step-up Cuk converter based on a switched-inductor (SL) and switched-capacitor (SC) techniques for renewable energy applications, such as photovoltaic and fuel cells. These kinds of Cuk converters provide a negative-to-positive step-up dc–dc voltage conversion. The proposed three topologies SLSC Cuk converters increase the voltage boost ability significantly using the switched-inductor and switched-capacitor techniques compared with the classical Cuk and boost converters. The proposed Cuk converters are derived from the classical Cuk converter by replacing the single inductor at the input and output sides with a SL and the transferring energy capacitor by a SC. The main advantages of the proposed SLSC Cuk converters are achieving a high voltage conversion ratio and reducing the voltage stress across the main switch. Therefore, a switch with low voltage rating and thus, of low $R_{DS-ON}$ can be used, and that leads to a higher efficiency. For example, the third topology have the ability to boost the input voltage up to 13 times when D = 0.75, D is the duty cycle. The voltage gain and the voltage stress across the main switch in the three topologies have been compared with the classical Cuk and boost converter. The proposed three topologies avoid using a transformer, coupled inductors, or extreme duty cycles leading to less volume, loss, and cost. The proposed SLSC Cuk converters are analyzed in continuous conduction mode (CCM), and they have been designed for 12 V input supply voltage, 100 W rated power, 50 kHz switching frequency, and 75% duty cycle. A detailed theoretical analysis of the CCM is represented and all the equations have been derived and matched with the results. The proposed three topologies SLSC Cuk converters have been simulated in MATLAB/SIMULINK and results are discussed.

This paper proposes a novel hybrid algorithm combining chaotic Jaya (CJaya) and sequential quadratic programming (SQP), namely CJaya-SQP, for solving the coordinated design problem of static var compensator (SVC) and power system stabilizers (PSSs). The CJaya serves as a global optimizer and the SQP as a local optimizer for fine-tuning the solution. In the proposed algorithm, chaotic maps are used to generate the initial solutions and control the search process. In order to prove the performance of the CJaya-SQP, a set of benchmark optimization problems is used where the results are compared with those of the basic Jaya and other recognized algorithms. The proposed optimization method is then applied for the optimal tuning of PSSs and SVC controllers in such a way that damping ratios and damping factors of the electromechanical modes are optimally improved. To illustrate the robustness of the CJaya-SQP-based coordinated PSSs and SVC controllers, the four-machine, two-area system is used. Eigenvalue analysis and nonlinear time-domain simulation vividly show that the CJaya-SQP-based coordinated controllers improve greatly the system’s dynamic stability with a robust damping of local and inter-area power oscillations.

This paper presents a novel of a transformerless step-up DC-DC converter based on a switched-inductor (SL) and switched-capacitor (SC) techniques. The main advantage of the proposed SLSC step-up converter is the ability to achieve very high voltage gain (>20) with reasonable voltage stress across the semiconductor switches. The presented paper shows a detailed analysis of the proposed SLSC step-up converter and a comparison considering other published step-up converter topologies. Theoretically, the proposed SLSC step-up converter can boost the input voltage to 23.5 times when D=0.75, which D means the duty cycle of the MOSFET. Such a large voltage gain can be used in renewable energy applications such as photovoltaic application to boost the output voltage which the output voltage is low. The proposed converter is analyzed in continuous conduction mode (CCM). The proposed converter has been designed for 12V input voltage, 280V output voltage, 200W rated power, 50kHz switching frequency, and 75% duty cycle. The proposed converter has been simulated in MATLAB/SIMULINK.

This paper discusses a switched inductor design for a non-isolated multilevel boost converter. A Non-isolated proposed multilevel boost converter is suitable to provide a high conversion ratio which essentially benefits renewable energy systems. In addition to the voltage stress reduction, the proposed switched inductor MBC has shown an improvement in voltage gain. The new switched inductor model has been inserted as an input into the multilevel boost converter. The proposed converter consists of 2N-1 capacitors, 4N-1 diodes, three inductors and a single switch. The proposed model is a three-level boost converter which is supplied by 12 V to produce 280 V at a 50 KHz switching frequency. A MATLAB/SIMULINK simulator was used to evaluate and test the proposed switched inductor model.