There is a growing interest in deploying medium voltage DC collection grids technologies in renewable energy applications to improve energy efficiency. Existing DC collection grids incorporate medium voltage DC/DC converters that suffer from bulky passive components such as a step-up transformer along with additional conversion stage to incorporate MPPT function. In response to these concerns, this paper proposes a new medium voltage DC collection grid method for large-scale PV plants with a Interleaved Modular Multilevel (IMMC) DC-DC boost converter. The proposed IMMC converter is synthesized with lower voltage half-bridge SiC inverter blocks connected in series to support medium voltage DC-DC conversion. The half-bridge blocks of the IMMC employ SiC switches, along with high frequency PWM operation enable compact size/weight along with high efficiency conversion. Simulation results are shown for 1500V (DC) to 16kV (DC) conversion with four series connected IMMC inverter blocks powered from two PV plants. A power sharing stage is an integral part of the proposed converter. This enable two series connected PV plants to supply unequal power under partial shading conditions. Control of the power sharing stage for varying insolation from PV (1000-500W/m2) due to shading effect is shown. A design example for 1MW PV power plant block based on the specifications derived from Kuwait Shagaya 60MW solar power plant is discussed. Experimental results on scale down laboratory prototype is included in the paper.

The research proposes a new oppositional sine cosine muted differential evolution algorithm (O-SCMDEA) for the optimal allocation of distributed generators (OADG) in active power distribution networks. The suggested approach employs a hybridization of the classic differential evolution algorithm and the sine cosine algorithm in order to incorporate the exploitation and exploration capabilities of the differential evolution algorithm and the sine cosine algorithm, respectively. Further, the convergence speed of the proposed algorithm is accelerated through the judicious application of opposition-based learning. The OADG is solved by considering three separate mono-objectives (real power loss minimization, voltage deviation improvement and maximization of the voltage stability index) and a multi-objective framework combining the above three. OADG is also addressed for DGs operating at the unity power factor and lagging power factor while meeting the pragmatic operational requirements of the system. The suggested algorithm for multiple DG allocation is evaluated using a small test distribution network (33 bus) and two bigger test distribution networks (118 bus and 136 bus). The results are also compared to recent state-of-the-art metaheuristic techniques, demonstrating the superiority of the proposed method for solving OADG, particularly for large-scale distribution networks. Statistical analysis is also performed to showcase the genuineness and robustness of the obtained results. A post hoc analysis using Friedman–ANOVA and Wilcoxon signed-rank tests reveals that the results are of statistical significance.

An interleaved multilevel dc-dc boost converter with direct input to output connection is proposed in this paper. The proposed converter is structured by adding an inverting stage to two multilevel boost converters and connecting them differentially to create a direct power flow path from the input to the output. The advantages of the proposed converter are: high voltage gain, partial power processing by the converter due to the direct connection between input and output, input current and output voltage ripple reduction due to the interleaved structure of the converter and low stress on the diodes and the switches. Several aspects of the converter analysis are included in the paper such as Continuous Conduction Mode (CCM), Boundary Conduction Mode (BCM), Discontinuous Conduction Mode (DCM), ripple reduction mechanism, converter's nonideal behavior and power processing calculations are discussed. A laboratory prototype of the interleaved multilevel boost converter is built to present the key waveforms of the proposed converter.

In this paper, a complete analysis of an LLC resonant converter with a customized rectifier structure is presented. The converter is intended for wide, low-input, high-output voltage DC bus applications. The performance of the converter is assessed using comprehensive time-domain and fundamental harmonic approximation (FHA), which demonstrates its capacity to operate across an ample range of voltages by precisely adjusting the rectifier structure. The converter’s capability is illustrated by deriving and discussing detailed mode operation, steady-state analysis, and DC gain equations. In order to verify the theoretical analysis, a prototype with a power output of 250 watts is constructed and subjected to testing. The results of the testing demonstrate that the converter is both feasible and effective. The experimental findings illustrate its capacity to manage vast voltage ranges while upholding high efficiency. In addition, the converter utilizes a frequency switching modulation (FSM) to connect with a photovoltaic (PV) panel and control the high output voltage. This demonstrates its adaptability in renewable energy applications. The validation is in accordance with theoretical predictions, demonstrating the converter’s high-efficiency performance and versatility.