Reptile search algorithm (RSA)-based selective harmonic elimination technique in Packed E-Cell (PEC-9) inverter

The multilevel inverters (MLIs) are capable of handling large quantities of power and generating high-quality output voltages. Consequently, the size of the filters is reduced, and the circuitry is simplified. As a result, they have a diverse range of uses in the industrial sector, especially in smart grids. The input voltage boosting feature is required to utilize the MLI with renewable energy. In addition, a large number of components are required to attain higher output voltage levels, which increases the cost of the circuit and weight. A variety of MLI topologies have been identified to reduce losses, device quantity, and device ratings. The selective harmonic elimination (SHE) approaches reduce distinct lower order harmonics by computing the ideal switching angles. This research presents a nine–level Packed E–Cell (PEC–9) inverter that uses selective harmonic elimination to eliminate total harmonic distortion. In order to calculate the best switching angle, the reptile search algorithm (RSA) is implemented in this paper, a nature–inspired metaheuristic algorithm inspired by the hunting behavior of the crocodile. The hunting behavior of crocodiles is implemented in two main steps: the first is encircling, which is accomplished by belly walking or high walking, and the second is hunting, which is accomplished by hunting cooperation or hunting coordination. In this technique, nonlinear transcendental equations have been solved. The simulation was run in the MATLAB R2021b software environment. The simulation results suggest that the RSA outperforms the other metaheuristic algorithms. Furthermore, the simulation result was validated on a hardware setup using DSP–TMS320F28379D in the laboratory

Recently Developed Reduced Switch Multilevel Inverter for Renewable Energy Integration and Drives Application: Topologies, Comprehensive Analysis and Comparative Evaluation

Recently, multilevel inverters (MLIs) have gained lots of interest in industry and academia, as they are changing into a viable technology for numerous applications, such as renewable power conversion system and drives. For these high power and high/medium voltage applications, MLIs are widely used as one of the advanced power converter topologies. To produce high-quality output without the need for a large number of switches, development of reduced switch MLI (RS MLI) topologies has been a major focus of current research. Therefore, this review paper focuses on a number of recently developed MLIs used in various applications. To assist with advanced current research in this field and in the selection of suitable inverter for various applications, significant understanding on these topologies is clearly summarized based on the three categories, i.e., symmetrical, asymmetrical, and modified topologies. This review paper also includes a comparison based on important performance parameters, detailed technical challenges, current focus, and future development trends. By a suitable combination of switches, the MLI produces a staircase output with low harmonic distortion. For a better understanding of the working principle, a single-phase RS MLI topology is experimentally illustrated for different level generation using both fundamental and high switching frequency techniques which will help the readers to gain the utmost knowledge for advance research

Improving energy capture and power quality of power electronic connected generation

Power electronic converter is a significant intermediate media for electric renewable energy systems when integrated into the utility grid. Renewable energy systems such as wind, solar and wave energy systems usually operate with irregular natural energy sources. Advanced energy conversion interfaces are therefore highly desirable for stable power supply, good system reliability and high energy extraction efficiency. This thesis investigates the power generation and conversion systems, with the concentrations on the long-term operation cost, full-power-range efficiency and power quality of power electronic converters, for wind, solar and wave energy applications. The story starts with a hybrid wind-solar energy system design targeting at improving energy yield and system reliability. Wind energy and solar energy, as two complementary energy resources, are combined in a single energy system that features improved energy supply stability and reduced energy storage requirement. Special adaptive energy extraction maximisation algorithms are developed for energy generators in order to increase the energy extraction efficiency. The overall energy cogeneration system can offer high productivity and robustness under varying weather conditions. In the second part of this thesis, a bidirectional DC-AC converter based on the well-established Silicon (Si) based two-level circuit and the emerging Silicon Carbide (SiC) based three-level circuit is investigated, with the motivation to enhance the full-power-range efficiency in renewable energy generation and conversion systems. The SiC based circuit is advantageous especially under low-power conditions due to its low switching losses. The costs of power electronics, especially the power semiconductor devices, are taken into account. The Si based circuit provides a more cost-effective option and lower conduction losses under high-power conditions to further improve the overall energy conversion efficiency. All these benefits are integrated in a single converter called hybrid level-matching (HLM) converter, which is comprised of parallel-connected SiC and Si based circuits. A model predictive control (MPC) algorithm is developed to assist the switching state selection for minimised power losses across the full power range. The proposed HLM converter shows similar power control quality and better full-power-range efficiency compared to its conventional counterparts. The operation of the HLM converter under the proposed MPC controller is experimentally verified by a lab-scale demonstrator. The final part of this thesis focuses on the control of an existing flying capacitor based multilevel converter known as stacked multicell converter (SMC). Considered as a superior DC-AC converter candidate in renewable energy standalone load applications, SMC can be controlled under different capacitor voltage ratios to increase the output voltage resolution. This is studied to explore the potential to improve power control quality within the same SMC circuit by applying different capacitor voltage set-points. The capacitor voltage balancing and the basic three-phase current control are achieved by means of a space vector based MPC algorithm. A method to reduce the computational burden by shrinking the space vector candidate size is proposed. The trade-off between capacitor voltage balancing and current reference tracking poses a major challenge to the SMC in its flexibility in capacitor voltage ratio choice. This is investigated in detail to verify the feasibility to reduce load harmonic distortion by modifying the traditional capacitor voltage ratio in a SMC with three stacked cells

Power Converters in Power Electronics

In recent years, power converters have played an important role in power electronics technology for different applications, such as renewable energy systems, electric vehicles, pulsed power generation, and biomedical sciences. Power converters, in the realm of power electronics, are becoming essential for generating electrical power energy in various ways. This Special Issue focuses on the development of novel power converter topologies in power electronics. The topics of interest include, but are not limited to: Z-source converters; multilevel power converter topologies; switched-capacitor-based power converters; power converters for battery management systems; power converters in wireless power transfer techniques; the reliability of power conversion systems; and modulation techniques for advanced power converters