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The design and implementation of a high-efficiency two-stage power electronic controller for feeding power from a photovoltaic (PV) array to the load/utility grid is proposed. The PV array is connected to the load/utility grid through a boost converter and an inverter. The boost converter is controlled by sinusoidal pulse width modulation (SPWM) pulses so as to get a clamped quasi-sinusoidal waveform at the DC link. The inverter converts the clamped quasi-DC voltage into AC voltage using the SPWM controller. At any time only one switch operates at high frequency, thus yielding reduction in the switching losses of the converters. The controller used for the inverter takes care of both the maximum power point tracking (MPPT) at unity power factor (UPF) and grid synchronization. The power electronic controller has been constructed using IGBT switches. The complete system has been modeled with MATLAB/Simulink software and simulation results are compared with experimental results. Experiments have been conducted at varying irradiations for both stand-alone (110 W) and grid-connected (110 V, 50 Hz) systems with a PV array of 130.2 V and 4.5 A employing the dSPACE DS1103 controller. The steady-state and dynamic responses of the proposed system are presented. © TÜBİTAK.

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Electrical

School of Electrical Engineering

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TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES

Power electronic controller with time sharing switching strategy for grid connected PV systems

This paper explains a photovoltaic (PV)-fed wireless electric vehicle (EV) battery-charging system used in a residential environment. Exploiting the benefits of renewable energy sources, a system is proposed which uses inductively coupled power transfer (ICPT) technology for transferring the PV-panel-generated power to charge EV battery wirelessly through power converter interfaces. The proposed system helps researchers to design an efficient PV-fed wireless EV battery-charging system to maintain optimal power flow through the power transferring coils. A controller is implemented in this proposed system to maintain a constant voltage across the output terminals to charge the EV battery irrespective of different solar irradiations. Simulation studies of the proposed system are carried out using PSIM software, and a laboratory prototype is fabricated and tested. Analysis of the system is carried out which helps in identifying the operating point of the system at which it can transfer the power efficiently in wireless mode for various frequencies and different air-gap spacing between the inductive coils of employed ICPT technique. Comparisons between the simulation results and experimental results have been correlated with each other, thereby proving the effectiveness of the designed prototype. © 2019 Oxford University Press. All rights reserved.

VIT Unitversity

Department of Energy and Power Electronics

Vellore Campus

International Journal of Power and Energy Systems

WIRELESS ELECTRIC VEHICLE BATTERY-CHARGING SYSTEM FOR SOLAR-POWERED RESIDENTIAL APPLICATIONS

Light Emitting Diode (LED) lighting plays a major role nowadays in industry and commercial applications. An efficient control technique is introduced for low power LED lighting with dimming characteristics. The driver circuit consists of a simple buck-boost converter with dc input voltage. The dimming characteristics are achieved by relating a low and high frequency control signal in order to eliminate flickering and colour shift. Software implementation is performed in MATLAB-simulink for a power rating of 10 W and tested under diverse brightness conditions. The simulation results demonstrate that dimming can be achieved with high efficiency. © Springer Nature Singapore Pte Ltd. 2018.

Advances in Power Systems and Energy Management Lecture Notes in Electrical Engineering

Buck–Boost LED Driver with Dimming Characteristics

The world's energy demand is growing and conventional sources are diminishing. Sustainable/renewable energy sources are gaining possibilities to come up with solutions to the long standing energy crisis, environmental problems, economic development and quality of life. By adopting renewable technologies in developing countries like India, effective steps are being taken towards clean mechanism and fortifying more sustainable future. From the past three decades there has been a strenuous pursuit to development, demonstration, application, production and research of renewable/sustainable technologies for use in distinct sectors. These efforts led to substantial improvement in renewable power generation. However, energy demand also increases largely in higher proportion to the production. It is observed that the current energy requirement is more than 1162 million units (MU) and the availability is 1138 MU leaving a shortage of 24 MU approximately. Hence, this paper focuses on discovering further availability of barren space for power generation from the renewable sources such as solar, wind, bio-energy and small hydro. The available unused potential of various energy sources in different states of India have been identified. The current status in market, policies, and various constraints of renewable technologies in India has also been summarized. © 2018, International Journal of Renewable Energy Research.

International Journal of Renewable Energy Research

Indian progress in the renewable technologies: A review on present status, policies, and barriers

This paper presents a single-phase photovoltaic (PV) system consisting of a bi-directional dc-dc converter (BDC) converter and a single-phase voltage source inverter (VSI). A PV panel act as primary source and a battery bank act as secondary source. The PV panel is operated at its maximum power point (MPP) by a maximum power point tracking (MPPT) controller. The boosted dc output voltage of the BDC is maintained constant using a voltage controller. This voltage is converted to ac by the VSI. In the presence of grid power and PV power, the battery bank absorbs charging power from the PV panel. The excess power available on the PV panel is delivered to the utility grid. In the absence of grid power, the load absorbs power from the PV panel or battery bank based on the level of solar irradiation. The proposed system rated for 250 Wp, 34.4 V, 9 A has been analysed in MATLAB/SIMULINK and the performance is compared in open and closed loop modes for various irradiations. THD in the ac output voltage and current is minimized using a passive LC filter. © 2017 Elsevier Ltd.

Materials Today: Proceedings

Stand-alone photovoltaic system with grid interfacing capability

Phasor measurement units (PMUs) placed in various nodes of power system network facilitates several tasks including optimum power flow, system control, contingency analysis, fault detection etc. For the above purposes, PMU’s are not required to place in all the bus in a power system. Also because of higher cost, optimal placement of PMU’s are done by using the binary search algorithm. The algorithm for optimal placement is tested for standard IEEE 7, 14 & 30 bus systems. Once the PMU’s are placed optimally, the next step involved is the fault location and diagnosis scheme which is capable of accurately identifying the location of a fault upon its occurrence. Two different algorithms has been developed for ring and radial type distribution feeders. These proposed algorithms are tested for different faults on both radial and ring power distribution systems. The scheme is capable of giving results results within 98 % accuracy of the line length.

Journal of Electrical Engineering

Identifying the fault location in distribution feeders with optimally placed PMU’S

This article presents a simple grid interactive system that extracts maximum power from a wind-driven permanent magnet synchronous generator using an integrated cascade boost converter and a three-phase line-commutated inverter. The firing angle of the line-commutated inverter is held constant at an appropriate value that provides a constant DC-link voltage, and only DC-link current is sensed for maximum power point tracking. For wide wind variation, maximum power from the permanent magnet synchronous generator is achieved using a simple load current (DC-link current) perturb and observe maximum power point tracking technique. This is obtained by varying the duty ratio of the integrated cascade boost converter with an adaptive incremental step that varies the load on the permanent magnet synchronous generator in accordance with changing wind. Experiments have been conducted on a 3-phase, 750-W, 500-rpm laboratory size permanent magnet synchronous generator. The operation and analysis of the proposed topology with a fixed firing angle for a line-commutated inverter is presented. The results obtained from MATLAB (The MathWorks, Natick, Massachusetts, USA) simulation are verified with experimental results, and a close correlation has been found, proving the efficacy of the system. © 2015 Taylor & Francis Group, LLC.

Electric Power Components and Systems

Power electronic interface with maximum power point tracking using line-commutated inverter for grid-connected permanent magnet synchronous generator

This paper presents a simple technique that efficiently tracks the maximum power from the photovoltaic array and delivers it to the grid. A controller has been developed for interfacing PV array with utility grid through a line commutated inverter. A PIC microcontroller together with the multiplier and opamp signal conditioning circuit has been used for the generation of firing pulses to the SCRs in the inverter. Using adaptive step perturb and observe (P&O) algorithm, the firing angle is automatically adjusted to extract maximum power from the solar PV array, which is fed to the utility grid. The complete closed loop scheme has been modelled and simulated in MATLAB environment and the simulation results are compared with experimental results. A PV array consisting of four panels each rated for 80 W, 21.2 V, 5.17 A has been used for the experiment. It is found that the experimental and simulation results have very close agreement. © Research India Publications.

International Journal of Applied Engineering Research

Development of a simple power electronic controller for grid connected PV systems

A power electronic interface with maximum power point tracking (MPPT) for grid connected photovoltaic (PV) systems using an integrated cascade boost converter (ICBC) and line commutated inverter (LCI) has been proposed. The variable dc voltage of the PV array is fed as input to the ICBC and the output voltage of the ICBC is maintained constant with the firing angle of the LCI being fixed at an appropriate value greater than 90°. The interesting feature of this scheme is that, it is not mandatory that the constant dc-link voltage should be more than the peak value of the grid voltage. As the array voltage is now boosted and fixed at the dc link, any variation in the PV output power is reflected in the variation of the dclink current and hence only one parameter (the dc-link current) sensing is required for the MPPT. Furthermore, the proposed controller has made it possible to dispense with the step up transformer between the LCI and the utility grid. The complete scheme has been constructed and experiments have been conducted on an 84 V, 10 A PV array feeding power to a threephase 230 V utility grid and the experimental results are compared with the MATLAB simulation results. The steady-state analysis of the overall system and the experimental results confirm the validity of the proposed controller and the efficacy of the analysis. © The Institution of Engineering and Technology 2014.

IET Power Electronics

Simple power electronic controller for photovoltaic fed grid-tied systems using line commutated inverter with fixed firing angle

This study presents a hybrid technique that offers constant power operation for single-phase grid-tied photovoltaic (PV) systems while performing maximum power point tracking function. A boost converter and a line commutated inverter (LCI) have been used for interfacing PV array with utility grid. Fixed firing angle of the LCI keeps the dc-link voltage constant and the boost converter extracts maximum power from the solar PV array by simply adjusting the duty ratio of the boost converter. A lowcapacity battery bank connected at the dc link is used to deliver constant power to grid. Harmonic filter is eliminated as the system inherently delivers quality supply with reduced current harmonics. PIC microcontrollers have been programmed for generating pulses to the inverter and the boost converter. The system has been simulated in MATLAB/Simulink and the simulation results are presented. The parameters of a PV panel rated for 100 W, 21.5 V and 6.83 A have been used for the simulation. Experiments have been conducted on the 21.5 V, 6.83 A PV panel for obtaining a constant power of 80 W with varying irradiation and the results correlate with the simulation study. © The Institution of Engineering and Technology 2014.

Hybrid power electronic controller for combined operation of constant power andmaximum power point tracking for single-phase grid-tied photovoltaic systems

The implementation of a simple power converter for a wound rotor induction generator employing a three phase diode bridge rectifier and a line commutated inverter in the rotor circuit for super synchronous speeds has been proposed. The detailed working of the system in power smoothing mode and maximum power point tracking mode is presented. The current flow in the rotor circuit is controlled (by controlling the firing angle of the line commutated inverter) for controlling the stator power in both the modes. An 8 bit PIC microcontroller has been programmed to vary the firing angle of the line commutated inverter. Experiments have been carried out on a 3-phase, 3. 73 kW, 400 V, 50 Hz, 4-pole, 1500 r/min wound rotor induction generator and the results obtained with the generator supplying power in both the modes are furnished. The complete scheme has been modeled using MATLAB/SIMULINK blocks and a simulation study has been conducted. The experimental waveforms are compared with the simulation results and a very close agreement between them is observed. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Frontiers in Energy

A unified power electronic controller for wind driven grid connected wound rotor induction generator using line commutated inverter

A simple power electronic controller employing boost converter and SCR based line commutated inverter (LCI) for interfacing PV array with utility grid has been proposed. The variable voltage of PV array is boosted to a fixed value and is connected to the line commutated inverter, which operates with a fixed firing angle more that 90°. The grid voltage and firing angle will determine the constant dc voltage of boost converter. As the output of boost converter is maintained constant, any variation in PV array output voltage will result in variation of dc link current. Thus MPPT is achieved by tracking dc link current alone. The complete scheme has been constructed and experiments have been conducted on a 84 V, 4.7 A PV array-interfaced with a utility grid of 110 V and the results are furnished. An 8051 μC has been employed for generating trigger pulses to the SCRs and a simple analog controller for varying the duty ratio of the boost converter. The experimental results are compared with simulation results and a close agreement between them is observed. ©2012 IEEE.

IEEE International Conference on Sustainable Energy Technologies, ICSET

A power electronic controller for PV-tied grid-connected system with single parameter sensing for MPPT using boost converter and line-commutated inverter