Power electronic converters are used to nullify the input fluctuations from a solar photovoltaic unit due to intermittent solar irradiance and to make the terminal voltage grid compatible with desired frequency. The conventional two-level converters suffer from low power quality and high voltage stress. In this paper, a new multilevel inverter topology called Dual Source Multilevel Inverter (DS-MLI) with fewer power switches is proposed for solar PV power conversion systems. It is capable of operating in symmetric and asymmetric operating modes without the need for cascading. This reduces the switching components required to produce a given number of levels in the staircase voltage waveform. A closed-loop control algorithm is designed using the state-space averaging technique, and the dynamic behavior of the system under step change is assessed. The simulation is carried out in MATLAB environment. The experimental prototype of DS-MLI rated 1 kW is fabricated using FGA25N120-ANTD IGBTs, and an eco-sense made solar PV emulator is used for analyzing the performance of DS-MLI while interfacing with solar PV unit. The suggested scheme is compared with its conventional counterpart in the aspects of components required, cost and efficiency and the results are presented INDEX TERMS DS-MLI, Multilevel inverter, Solar PV, Power Conversion, Fundamental frequency switching.
Characteristics like reliability and modularity of solar photovoltaic (SPV) units makes them one of the apt options for generating electric power. However, the input intermittency is their major lacuna, and power electronic circuits are being used to nullify this effect. A solar photovoltaic power conversion process includes a DC-DC converter in the plant side to deliver a fixed DC voltage and a DC-AC converter in the grid side for converting DC voltage in to grid compatible AC voltage. The high duty ratio of typical DC-DC boost converters limits the switching frequency and efficiency. In this article, a way to enhance the performance of a SPV unit using an improved quadratic boost converter (IQBC) is analysed. It can deliver a higher output voltage at lower duty ratio with Perturb and Observe (P&O) algorithm-based Maximum Power Point Tracking (MPPT). A 250 W prototype of IQBC-based Solar PV power conversion system (SPVPCS) is developed, and its performance is compared against conventional and quadratic boost converters and found that the IQBC-based solar power conversion system is efficient and the results are presented. K E Y W O R D S boost converter, duty ratio, improved quadratic boost converter, solar PV conversion, system, voltage gain 1 | INTRODUCTION Renewable energy resources are getting much importance nowadays due to wider exploitation of fossil fuels. 1 Even though there are several renewable energy sources available, wind and solar energy are gaining an edge over the other resources due to their reliability and ability to deliver higher power levels. But it does have a limitation; that is, the input for solar PV system is highly intermittent. This effect of input intermittency can be nullified using power converters. 2,3 DC-DC converters are used to nullify these fluctuations through step up/step down of DC voltage from solar PV panel. Even though higher voltage can be obtained by connecting panels in series, losses due to partial shading and cost will be the drawbacks. 4-6 To achieve voltage boost, a boost converter have to be operated at high duty ratio. While operating the converter in higher duty ratio, issues like high switching voltage stress, limited switching frequency, reverse recovery problem and electromagnetic interference may occur, and also, it affects the efficiency of the converter. 7 As a remedy to the above setbacks, many DC-DC boost converter topologies are proposed recently. 8 Cascaded boost converter gives an opportunity of obtaining high output voltage with less duty ratio. 9,10 Even though it offers individual panel level MPPT, its cascaded structure raises the cost of overall system. 11 SEPIC converter embedded with the MPPT
India has enormous wind potential and average wind velocity is about 6 m/s, whereas the conventional wind turbine mechanism is operated at 7 m/s–12.5 m/s. It is necessary to design low speed wind energy conversion to harvest the electrical energy from wind. Mostly, Radial flux permanent magnet generator (RFPMG) is used for low speed wind turbine applications. This Conventional RFPMG has the drawbacks of low flux density and increase in weight due to large number of poles accommodation. In order to overcome the above setbacks, this paper proposes a double sided coreless axial flux permanent magnet generator (AFPMG) for low speed wind energy conversion applications. The performance analysis of the proposed AFPMG is carried out through finite element method using ANSYS Maxwell software. Finally the performance of RFPMG and AFPMG is compared based on the flux linkage, flux density, induced emf, stator current, moving torque, cogging torque, Total Harmonic Distortion (THD), material consumption, losses and efficiency. It is evident from the results that AFPMG gives the better performance than RFPMG in all such aspects.
The electric vehicle market has surged the consideration of charging station requirements in the commercial and residential areas of the urban regions. The addition of charging stations at the existing power network introduces a greater challenge on voltage stability and losses. The effect of the charging station can be addressed through the optimal integration of Distributed Generation (DG) units into the network. The improper placement of DG units can jeopardize the network stability. These issues are addressed by optimal placement of DG units and charging stations in the network to improve voltage, reduce transmission loss and maximize the charging station capacity. Here the objectives are considered as a multi-objective problem and solved using an enhanced Ant-lion optimization algorithm. The proposed method is implemented and tested over IEEE – 33, 69 and 94 radial bus system in MATLAB R2020a version. In IEEE – 33 bus system, the total loss reduction of 67.63% and the minimum voltage of 0.981 is attained with 2909.2 kW of DG and 1770.7 kW of charging station. The voltage stability index is improved to 0.92. The efficacy of the proposed method is evaluated through comparison with existing methods such as Genetic Algorithm (GA) with VRP method, Harris Hawks Optimization (HHO) and Particle Swarm Optimization (PSO). It is evident that the proposed method gives improved performance than other methods.
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