Ganesan Saravana Ilango
Bio: Ganesan Saravana Ilango is an academic researcher from National Institute of Technology, Tiruchirappalli. The author has contributed to research in topics: AC power & Stator. The author has an hindex of 6, co-authored 15 publications receiving 475 citations.
TL;DR: In this paper, the physical location of the modules in a total cross-tied (TCT) connected PV array is arranged based on the Su Do Ku puzzle pattern so as to distribute the shading effect over the entire array.
Abstract: Partial shading of PV arrays reduces the energy yield of PV systems and the arrays exhibit multiple peaks in the P-V characteristics. The losses due to partial shading are not proportional to the shaded area but depend on the shading pattern, array configuration and the physical location of shaded modules in the array. This paper presents a technique to configure the modules in the array so as to enhance the generated power from the array under partial shading conditions. In this approach, the physical location of the modules in a Total Cross Tied (TCT) connected PV array are arranged based on the Su Do Ku puzzle pattern so as to distribute the shading effect over the entire array. Further, this arrangement of modules is done without altering the electrical connection of the modules in the array. The Su Do Ku arrangement reduces the effect of shading of modules in any row thereby enhancing the generated PV power. The performance of the system is investigated for different shading patterns and the results show that positioning the modules of the array according to “Su Do Ku” puzzle pattern yields improved performance under partially shaded conditions.
TL;DR: A system is developed for selecting the operating mode of the bidirectional converter by sensing the battery voltage and the viability of the scheme has been ascertained by performing experimental studies on a laboratory prototype.
Abstract: The growing concern for energy saving has increased the usage of LED-based street lights, electronic chokes, compact fluorescent lamps, and inverter-fed drives. Hence, the load profile seen by the electrical grid is undergoing a notable change as these devices have to operate from a dc source. Photovoltaics (PV) being a major energy source, the aforementioned loads can be connected directly to the dc bus. A grid-connected PV system involves a power source (PV array), a power sink (load), and two power sources/sink (utility and battery), and hence, a power flow management system is required to balance the power flow among these sources. One such system is developed for selecting the operating mode of the bidirectional converter by sensing the battery voltage. The viability of the scheme has been ascertained by performing experimental studies on a laboratory prototype. The control strategy is digitally implemented on an Altera Cyclone II Field Programmable Gate Array (FPGA) board, and the algorithm is verified for different modes of operation by varying the load. Experimental results are presented to bring out the usefulness of the control strategy.
TL;DR: In this paper, a simple and implicit sensorless algorithm for estimating the rotor position and speed of the doubly-fed induction machine is proposed, which does not involve integration, recursive techniques, re-computations or programmable low-pass filters etc.
Abstract: A simple and implicit sensorless algorithm for estimating the rotor position and speed of the doubly fed induction machine is proposed in this study. Instead of computing the stator magnetic flux directly or indirectly, the stator flux vector components in the stationary reference frame are substituted with analytical equivalents in terms of measurable stator and rotor quantities. Thus, it is an implicit estimation process devoid of computing any flux terms and requires only the measured stator voltage and currents in stator and rotor windings apart from knowledge of the machine parameters. It is an open-loop scheme. However, it does not involve integration, recursive techniques, re-computations or programmable low-pass filters etc. Starting on the fly, accurate estimation near synchronous speed, immunity against variation in stator and rotor resistances or in the magnetising inductance are the principal advantages of the algorithm. Reduced complexity and the computational burden facilitate the easy implementation of the algorithm on a low-cost fixed point processor. Excellent agreement between the simulation and test results on a laboratory doubly fed induction motor validates the proposed estimation algorithm implemented for the vector control of a doubly fed induction motor. On the whole, the estimation algorithm is a new insight that holds promise in the area of sensorless control of the DFIM, whether used as a motor or as a generator.
TL;DR: In this paper, the rotor position and speed of a doubly-fed induction machine is computed in a straightforward manner obviating the need for estimation, which is an open-loop technique and does not involve integration, recursive techniques, recomputations or programmable low-pass filters.
Abstract: This paper proposes a simple yet versatile rotor position computation algorithm (RPCA) for the rotor position and speed of a doubly fed induction machine. The rotor position is computed in a straightforward manner obviating the need for estimation. The resolved components of stator flux vector are computed using measurable stator and rotor quantities. Although it is an open-loop technique, it does not involve integration, recursive techniques, recomputations or programmable low-pass filters, etc. Starting on the fly, accurate computation near and through the synchronous speed, immunity against fluctuations in the grid voltage, and frequency are the other advantages of the algorithm. Reduced complexity and the computational burden facilitate the easy implementation of the algorithm on a low-cost fixed-point processor. Furthermore, unlike most techniques reported so far, there is no need to assume a constant stator flux since the algorithm is versatile to allow for variations in the grid or stator flux. For the purpose of verification, the proposed RPCA, employed in decoupled power control, is implemented for the laboratory test bench with a 3-hp doubly fed induction generator (grid-connected) system and a TMS320LF2407A DSP controller. The efficacy of the algorithm is demonstrated through the extensive experimental results. Overall, the very encouraging results endorse the proposed algorithm.
TL;DR: In this paper, the authors discuss the major challenges of providing energy access to all its citizens, heavy dependence on fuel imports for energy security, and complying with international protocols on climate change mitigation, although the economic and social development is the foremost priority.
Abstract: —India is faced with the major challenges of (a) providing energy access to all its citizens, (b) heavy dependence on fuel imports for energy security, and (c) complying with international protocols on climate change mitigation, although the economic and social development is the foremost priority. The increase in energy demand due to growing population and industrialization in the face of depleting fossil fuel resources has stimulated the country's efforts in adopting power generation from renewable energy sources. Starting with 0.34 GW (2%) out of 17 GW of the country's total installed capacity in the year 2002, the share of renewable power generation has reached 31.7 GW (12.5%) of 250 GW as of 2014. In the aspect of total installed renewable power generation, India occupies the fifth position in the world today. While the governmental policies have steadily encouraged the adoption of renewable power generation, there is need and potential for more vigorous engagement in pursuit of achieving pow...
TL;DR: A comprehensive review of the approaches proposed and used by authors of many papers is conducted in this paper, which includes both the standalone hybrid renewable energy systems and the grid-connected hybrid renewable systems.
Abstract: Variability and intermittency are some of the main features that characterize renewable energy sources. Intermittency usually includes both predictable and unpredictable variations. The many drawbacks of intermittency of renewable sources can be overcome by considering some special design considerations. Integrating more than one renewable energy source and including backup sources and storage systems are among the few measures to overcome these drawbacks. These additional design considerations usually increase the overall cost of the renewable system. Furthermore, the presence of more than one energy supply/storage system requires the control of energy flow among the various sources. Therefore, optimizing the size of the components and adopting an energy management strategy (EMS) are essential to decreasing the cost of the system and limiting its negative effects. The energy management strategy is commonly integrated with optimization to ensure the continuity of load supply and to decrease the cost of energy production. Therefore, energy management is a term that collects all the systematic procedures to control and minimize the quantity and the cost of energy used to provide a certain application with its requirements. The energy management strategy usually depends on the type of energy system and its components. Various approaches and techniques have been used to develop a successful energy management strategy. In this paper, a comprehensive review of the approaches proposed and used by authors of many papers is conducted. These approaches include both the standalone hybrid renewable energy systems and the grid-connected hybrid renewable systems. More attention is focused on popularly used techniques to address the features of each system. The selected papers in this review cover the various configurations of the hybrid renewable energy systems for electric power generation only.
TL;DR: This paper aims at reviewing part of these topics (MPPT, current and voltage control) leaving to a future paper to complete the scenario.
Abstract: Photovoltaic Systems (PVS) can be easily integrated in residential buildings hence they will be the main responsible of making low-voltage grid power flow bidirectional. Control issues on both the PV side and on the grid side have received much attention from manufacturers, competing for efficiency and low distortion and academia proposing new ideas soon become state-of-the-art. This paper aims at reviewing part of these topics (MPPT, current and voltage control) leaving to a future paper to complete the scenario. Implementation issues on Digital Signal Processor (DSP), the mandatory choice in this market segment, are discussed.
TL;DR: In this paper, the authors summarize the control objectives and development methodologies in the recently proposed microgrid supervisory controllers (MGSC) and energy management systems (EMS) and provide a detailed methodology review with emphasis on representative applications and research works.
Abstract: Microgrids (MGs), featured by distributed energy resources, consumption and storage, are designed to significantly enhance the self-sustainability of future electric distribution grids. In order to adapt to this new and revolutionary paradigm, it is necessary to control MGs in intelligent and coordinated fashion. To this aim, a new generation of advanced Microgrid Supervisory Controllers (MGSC) and Energy Management Systems (EMS) has emerged. The aim of this paper is to summarize the control objectives and development methodologies in the recently proposed MGSC/EMS. At first, a classification of control objectives is made according to the definition of hierarchical control layers in MGs. Then, focusing on MGSC/EMS related studies, a detailed methodology review is given with emphasis on representative applications and research works. Finally, the conclusions are summarized and the proposals of future research directions in this area are given.
TL;DR: Two strategies are proposed with the related design principles to control the new energy-stored qZSI when applied to the PV power system and prove the effectiveness of the proposed control of the inverter's input and output powers and battery power regardless of the charging or discharging situation.
Abstract: The quasi-Z-source inverter (qZSI) with battery operation can balance the stochastic fluctuations of photovoltaic (PV) power injected to the grid/load, but its existing topology has a power limitation due to the wide range of discontinuous conduction mode during battery discharge. This paper proposes a new topology of the energy-stored qZSI to overcome this disadvantage. The operating characteristic of the proposed solution is analyzed in detail and compared to that of the existing topology. Two strategies are proposed with the related design principles to control the new energy-stored qZSI when applied to the PV power system. They can control the inverter output power, track the PV panel's maximum power point, and manage the battery power, simultaneously. The voltage boost and inversion, and energy storage are integrated in a single-stage inverter. An experimental prototype is built to test the proposed circuit and the two discussed control methods. The obtained results verify the theoretical analysis and prove the effectiveness of the proposed control of the inverter's input and output powers and battery power regardless of the charging or discharging situation. A real PV panel is used in the grid-tie test of the proposed energy-stored qZSI, which demonstrates three operational modes suitable for application in the PV power system.
TL;DR: A unified energy management scheme is proposed for renewable grid integrated systems with battery-supercapacitor hybrid storage that enables the real power transfer along with ancillary services such as current harmonic mitigation, reactive power support, and power factor improvement at the point of common coupling.
Abstract: In this paper, a unified energy management scheme is proposed for renewable grid integrated systems with battery–supercapacitor hybrid storage. The intermittent nature of renewable-energy resources (RES), coupled with the unpredictable changes in the load, demands high-power and high-energy-density storage systems to coexist in today's microgrid environment. The proposed scheme dynamically changes the modes of renewable integrated systems based on the availability of RES power and changes in load as well. The participation of battery–supercapacitor storage to handle sudden/average changes in power surges results in fast dc link voltage regulation, effective energy management, and reduced current stress on battery. In addition, the proposed energy management scheme enables the real power transfer along with ancillary services such as current harmonic mitigation, reactive power support, and power factor improvement at the point of common coupling. The proposed scheme is validated through both simulation and experimental studies.