Search

An isolated interleaved boost converter (IIBC) based single-phase grid-interfaced photovoltaic system (SPGIPS) and its control are proposed in this article. The proposed double-stage SPGIPS consists of an IIBC and a single-phase full bridge voltage source converter (SPFBVSC). An IIBC is designed using a high-frequency transformer (HFT), two primary inductors, and two static switches with its emitter shared with photovoltaic (PV) panel ground. Shared emitter terminal reduces the gate control circuit complexity and HFT facilitates a galvanic isolation between PV panels and the utility grid, and thus it mitigates the appearance of leakage current. An IIBC reduces the ripple in PV panel current and voltages and therefore guarantees improved maximum power point operation (MPPO) of the PV system. To ensure the MPPO at PV panel terminals, a sliding mode control is used. The output DC terminals of IIBC are interfaced with self-commutated switches based SPFBVSC. To synchronize SPFBVSC with the utility grid, a new modified fourth-order generalized integrator (mFOGI) is developed. The mFOGI provides stable synchronization signal even under presence of noise, under/over shoot, or DC offset in the AC supply voltage. The proposed SPGIPS control and its performance are validated on Simulink and prototype system. [ABSTRACT FROM AUTHOR]

This paper presents a fifth-order generalized integrator (FOGI) as an orthogonal signal generator (OSG) to obtain a grid synchronization signal for a double-stage single-phase grid-interfaced photovoltaic supply system (GIPVSS). The proposed GIPVSS consists of a single-ended primary inductor converter (SEPIC) and a H-bridge voltage source converter (HBVSC) to transfer solar power to the grid system. The SEPIC controls maximum power delivery (MPD) from the Photovoltaic (PV) array and feeds that power to the grid via an HBVSC. In this study, all energy storage elements (inductors and capacitors) of SEPIC are considered with their effective series resistance (ESR). The dynamic modeling of SEPIC is obtained using a small signal analysis. The control of VSC allows harmonics' mitigation and power factor improvements. A FOGI and a second-order adaptive filtering approach are used in controling VSC. The FOGI is used to obtain a grid synchronization signal from sensed grid voltage under disturbances. The second-order adaptive filtering approach is used to obtain an active load current component. The comparative analysis of FOGI with other reported algorithms is carried out under harmonics in sensed grid voltage. The effectiveness of the proposed system and its control is validated in a laboratory prototype using a Launch Pad TMS320F28379D digital signal processor (DSP). [ABSTRACT FROM AUTHOR]

Due to the increase in environmental concerns, it becomes mandatory now to focus on energy management and the planning of resources. An integration of distributed generation resources with conventional sources is gaining popularity. The hybrid modeling of the power system poses a complex and challenging optimization problem without getting trapped in a local optimum. A novel Hybrid Statistical Multiswarm Particle Swarm Optimizer-Sine Cosine Algorithm (HSMPSO-SCA) is developed in this paper, and its performance is evaluated on various test benchmark functions. The real operating conditions such as valve point loading, prohibited zones, ramp rate limits and uncertainties in solar and wind power generation for the IEEE 30 bus system are considered for combined emission economic load dispatch (CEELD). The performance of the HSMPSO-SCA is also analyzed for the solution of CEELD for various standard test systems with interaction of solar and wind plants. The efficacy of the proposed HSMPSO-SCA is found to be much better than various metaheuristics, hybrid and multi-agent algorithms in minimizing cost along with emissions optimally and achieves better accuracy and a faster convergence rate. [ABSTRACT FROM AUTHOR]

An energy management in micro grid portrays a significant role in coordinating the generation with the load demand and it is characterized as an optimization problem evaluated for economic dispatch (ED). In microgrid, energy management issues have thus far primarily been addressed with the purpose of lowering the operational costs. However, for a microgrid system to manage energy effectively, the environmental problems, or issues regarding emission must be addressed. In this research work, a novel metaheuristic approach, known as farmland fertility algorithm (FFA) is proposed for obtaining ED and integrated economic emission dispatch (IEED). The different test cases for ED and IEED are considered to minimize the fuel and the emission cost respectively. For the different cases contemplated for ED and IEED, the generation cost reduces after the inclusion of RES, and also in the case when wind energy source is included alone. These results depict that the ED and IEED perform using FFA achieves a cost optimization of 9.2% and 19.51% respectively. The ED and IEED with FFA offer more cost saving and provides reduced emission in comparison to reduced gradient method (RGM), ant colony optimization (ACO), cuckoo search algorithm (CSA), interior search algorithm (ISA), Bat algorithm (BA) and directional bat algorithm (dBA). [ABSTRACT FROM AUTHOR]

Rapid bio-assessment of River Ujh has been carried out using benthic macro-invertebrates based on the Hindu-Kush Himalayan (HKH) rapid field bio-assessment protocol. Meanwhile, the assessment of water quality in the river was performed using the weighted arithmetic water quality index (WA-WQI), based on physiochemical parameters. Furthermore, the biotic indices (such as Nepalese Biotic Score (NEPBIOS), modified NEPBIOS, HKHBIOS, Stream Invertebrate Grade Number-Average Level (SIGNAL), SIGNAL 2, biological monitoring working party and biological water quality class criteria) were used for biological assessment of water quality. The water samples were collected from eight sampling stations during the month of February in year 2015. The results indicate that the overall water quality in the river was poor (i.e. not suitable for drinking), as average WA-WQI was 78.65 in the sampling month. During the analysis of micro-invertebrate occurrence, a total of 10 taxonomic groups, 36 families and 2193 individual organisms were identified. Among all organisms, the members of taxonomic groups Ephemeroptera and Trichoptera were found in abundance at all sampling stations. However, the NEPBIO score was found to be decreasing from 6.1 at first sampling stations (S1, located in upstream) to 4.8 at last (S8, located in downstream), which indicate the decline in abundance of organisms due to deterioration of water quality in the river. Therefore, it has been suggested the river water must be treated prior to use for drinking. It is recommended that biotic indices developed for bio-assessment of water bodies in the central Himalayan region can also be applied suitably to assess the water quality status in River Ujh. [ABSTRACT FROM AUTHOR]

This article deals with the performance evaluation of fixed-speed and variable-speed stand-alone wind energy conversion systems using an isolated asynchronous generator. A voltage and frequency controller for an isolated asynchronous generator based variable-speed stand-alone wind energy conversion system is investigated using two back-to-back connected voltage source converters and a battery energy storage system. A three-leg insulated-gate bipolar transistor based voltage source converter is used at the machine side for variable-voltage–variable-frequency energy conversion, and a four-leg insulated-gate bipolar transistor based voltage source converter is used between the load terminals and intermediate DC link for feeding regulated voltage and frequency supply. A voltage and frequency controller for an isolated asynchronous generator based fixed-speed stand-alone wind energy conversion system is also designed and modeled using a four-leg voltage source converter and battery energy storage system. A detailed performance evaluation is made between fixed-speed and variable-speed stand-alone wind energy conversion systems using wind data obtained for Jakhau (Gujarat) situated in India. [ABSTRACT FROM AUTHOR]

This paper deals with an implementation of voltage and frequency controller (VFC) for isolated asynchronous generator-based three-phase autonomous wind energy conversion system. The focus of the proposed work is to provide a feasible solution for rural communities to serve their electricity needs. The least mean square algorithm is used for the extraction of active and reactive power components of the load currents. A three-leg voltage-sourced converter with a battery energy storage system is used as a VFC. The control algorithm is implemented using a digital signal processor. The steady-state and dynamic performances of VFC are demonstrated through test results under static and dynamic loads. [ABSTRACT FROM AUTHOR]

This paper deals with an artificial neural network based control of the voltage and frequency (VF) of autonomous wind power generation using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference generator currents are estimated using the adaptive linear neuron and its training through least mean square (LMS) algorithm to control the VF of an IAG system. Three-leg voltage source converter (VSC) with an isolated T-connected transformer is used as an integrated VSC. The integrated VSC with a battery energy storage system is used to control the active power of the wind energy conversion system (WECS). Bi-directional power flow capabilities of the proposed VF controller in WECS are demonstrated through simulation results. The proposed controller functions as a VF regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. The WECS is modeled and simulated in the MATLAB using the Simulink and the sim power system toolboxes. [ABSTRACT FROM AUTHOR]