Power electronic converters are used to transform one form of energy to another. They are classified into four types depending upon the nature of the input and output voltages. The inverter is one among those types; it converts direct electrical current into alternating electrical current at desired frequency. Conventional types of inverters are capable of producing voltage at the output terminal that can only switch between two levels. The range of output voltage generated at the output is low when they are used for high power applications. To improve the voltage profile and efficiency of the overall system, multilevel inverters (MLIs) are introduced. In multilevel inverters the voltage at the output terminal is generated from several DC voltage levels fed at its input. The generated output is more appropriate to a sine wave and the dv/dt rating is also less leading to the reduction in EMI. Though they possess many advantages compared to the conventional inverters, the structural complexity and triggering techniques involved in designing multilevel inverters are high. Many studies are being carried out in defining new topologies of MLI with reduced switch as well as with the implementation of different PWM techniques. This paper will provide an extensive review on variety of MLI configurations based on the parameters such as the number of switches, switching techniques, symmetric, asymmetric, hybrid topologies, configurations based on applications, THD and power quality.
The consumer adoption of electric vehicles (EVs) has become most popular. Numerous studies are being carried out on the usage of EVs, the challenges of EVs, and their benefits. Based on these studies, factors such as battery charging time, charging infrastructure, battery cost, distance per charge, and the capital cost are considered factors in the adoption of electric vehicles and their interconnection with the grid. The large-scale development of electric vehicles has laid the path to Photovoltaic (PV) power for charging and grid support, as the PV panels can be placed at the top of the smart charging stations connected to a grid. By proper scheduling of PV and grid systems, the V2G connections can be made simple. For reliable operation of the grid, the ramifications associated with the PV interconnection must be properly addressed without any violations. To overcome the above issues, certain standards can be imposed on these systems. This paper mainly focuses on the various standards for EV, PV systems and their interconnection with grid-connected systems.
The growth of distributed power generation using renewable energy sources has led to the development of new-generation power electronic converters. This is because DC–DC converters and inverters form the fundamental building blocks in numerous applications, which include renewable integrations, energy harvesting, and transportation. Additionally, they play a vital role in microgrid applications. The deployment of distributed energy resources (DERs) with renewable sources such as solar has paved the way for microgrid support systems, thus forming an efficient electric grid. To enhance the voltage of such sources and to integrate them into the grid, high-gain DC–DC converters and inverter circuits are required. In this paper, a novel single-switch high-gain converter (HG-SIQBC) with quadratic voltage gain and wide controllable range of load is proposed, the output of which is fed to a modified multilevel inverter for conversion of voltage. The overall performance of the newly designed converter and inverter is analyzed and compared with the existing topologies. A prototype of the investigated multilevel inverter is designed and tested in the laboratory. Development and testing of such novel topologies have become the need of the hour as the grid becomes smarter with increased penetration of distributed resources.
The utilization of plug-in electric vehicles (PEV) has started to garner more attention worldwide considering the environmental and economic benefits. This has led to the invention of new technologies and motifs associated with batteries, bidirectional converters and inverters for Electric Vehicle applications. In this paper, a novel design and control of chopper circuit is proposed and configured with the series and parallel connection of the power electronic based switches for two-way operation of the converter. The bidirectional action of the proposed converter makes it suitable for plug-in electric vehicle applications as the grid is becoming smarter. The DC–DC converter is further interfaced with the designed multilevel inverter (MLI). The reduced switches associated with the novel design of MLI have overcome the cons associated with the conventional inverters in terms of enhanced performance in the proposed design. Further, novel control strategies have been proposed for the DC–DC converter based on Proportional Integral (PI) and Fuzzy based control logic. For the first time, the performance of the entire system is evaluated based on the comparison of proposed PI, fuzzy, and hybrid controllers. New rules have been formulated for the Fuzzy based controllers that are associated with the Converter design. This has further facilitated the interface of bidirectional DC–DC converter with the proposed MLI for an enhanced output voltage. The results indicate that the proposed hybrid controller provides better performance in terms of voltage gain, ripple, efficiency and overall aspects of power quality that forms the crux for PEV applications. The novelty of the design and control of the overall topology has been manifested based on simulation using MATLAB/SIMULINK.
1 July 2019 in Mehran University Research Journal of Engineering and Technology
The increasing demand for electricity has pushed more effort to focus on renewable energy sources to satisfy the consumer. The renewable energy sources are playing a major role in the generation of electricity. Out of all the renewable energy sources, solar has emerged as one of the best sources of energy since it is clean, inexhaustible and eco-friendly. However, the voltage generated by the solar cell is not sufficient for any consumer load and it is also variable. Therefore, it is necessary to implement DCDC converters for regulating and improving the output voltage of the solar panel. In order to extract the maximum output from the PV (Photovoltaic) panel, a comparative analysis of various MPPT (Maximum Power Point Tracking) algorithms is proposed in this paper. The proposed enhanced adaptive P&O (Perturb and Observe) algorithm is modeled and implemented with a high gain DC-DC converter. The converter investigated in this paper consists of a single power electronic switch (MOSFET) for its operation, which leads to reduction of switching and conduction losses. The proposed converter has less ripple content and a high conversion ratio. A simulation study of the proposed power electronic converter powered by PV source is carried out in MATLAB/SIMULINK and the results are validated using an experimental setup.