Qualification: 
Ph.D, M.E
a_vijayakumari@cb.amrita.edu

Dr. Vijayakumari A. currently serves as Associate Professor at Department of Electrical and Electronics Engineering, School of Engineering, Coimbatore Campus. Her areas of research include Power Electronics and Renewable Energy.

Publications

Publication Type: Conference Paper

Year of Publication Publication Type Title

2017

Conference Paper

V. Ankita and Dr. Vijayakumari A., “A reduced converter count solid state transformer for grid connected Photovoltaic applications”, in Proceedings of IEEE International Conference on Emerging Technological Trends in Computing, Communications and Electrical Engineering, ICETT 2016, 2017.[Abstract]


This paper presents a Solid State Transformer (SST) interface for grid connected Photovoltaic (PV) system. A new method is proposed for Maximum Power Point Tracking (MPPT) through a single phase inverter with phase displacement control. The inverter control variable is redefined such that it can be used for MPPT. Due to this control technique one converter stage for power tracking is eliminated, leading to a reduced component count for the overall system. The high frequency transformer's model parameters are designed for an operating frequency of 20 kHz for simulation studies. The grid side converter is controlled for synchronization and power flow using a Synchronous Reference Frame (SRF) current controller. The overall system is tested in simulation for a panel rating of 1.15 kWp under various insolation conditions and power balance is verified and presented. Testing is carried out under step change in the insolation to evaluate the performance of the SST interface under transient conditions. The proposed system is tracking the maximum power available from the panel and delivering it into the grid with high efficiency. The overall system efficiency and the high frequency transformer efficiencies are presented under various operating conditions. © 2016 IEEE.

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2017

Conference Paper

K. K. Khan and Dr. Vijayakumari A., “A dual mode control for bridgeless SEPIC power factor correction rectifier”, in Proceedings of IEEE International Conference on Emerging Technological Trends in Computing, Communications and Electrical Engineering, ICETT 2016, 2017.[Abstract]


This paper presents the design and development of a dual mode controlled bridgeless SEPIC unity power factor correction rectifier for a typical low power application like an LED driver. The proposed topology has reduced component count with reduced conduction losses because of no front end diode rectifier. The bridgeless SEPIC converter is designed to operate in discontinuous current mode so as to obtain a natural zero current turn off in output diode and zero current turn on in switches. This will reduce the complexity in control and provides voltage following capability for the source current. The proposed dual mode control circuit gives a supplementary control capability to attain sinusoidal current even in the presence of harmonics in source voltage. A harmonic detection is carried out on the source voltage and the control is directed according to the results either to voltage follower or average current control. The second control uses an extraction technique to get a sinusoidal current reference and maintains UPF even with the presence of harmonics in the source voltage. The proposed converter with its associated control is developed in MATLAB/Simulink for a power rating of 10W a practical rating of an LED load. Beside the normal operating conditions, the circuit is tested under varying source voltage, frequency and also with harmonic source voltage. The source current is found to be sinusoidal under all the conditions and the current THD is found to be well below 5% with unity power factor. © 2016 IEEE.

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2017

Conference Paper

P. V. Sandeep and Dr. Vijayakumari A., “Grid connected wind driven permanent magnet synchronous generator with high frequency solid state transformer”, in Proceedings of IEEE International Conference on Emerging Technological Trends in Computing, Communications and Electrical Engineering, ICETT 2016, 2017.[Abstract]


This paper presents the control of grid connected wind driven permanent magnet synchronous generator through solid state transformer with a high frequency multistage converter interconnect. Maximum power point tracking is carried out in the high frequency generator side converter stage where as the grid side converter takes care of the synchronization. The model parameters for the high frequency transformer are obtained by analytical calculation and the same is used in the simulation. A push pull converter with incremental conductance algorithm on the generator side tracks the MPP. It also converts the dc output into high frequency wave so that it can be directly applied to the primary of the high frequency transformer. The rectified secondary voltage is grid synchronized through the grid side inverter with synchronous reference controller. The entire system including the high frequency transformer is simulated in MATLAB/Simulink for a 2.5 kW PMSG. © 2016 IEEE.

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Publication Type: Journal Article

Year of Publication Publication Type Title

2016

Journal Article

Dr. Vijayakumari A., Devarajan, A. T., and Mohanrajan S. R., “Power angle control of a single phase grid connected photovoltaic inverter for controlled power transfer”, Advances in Intelligent Systems and Computing, vol. 397, pp. 451-461, 2016.[Abstract]


This paper focuses on the design and development of a 500 W, single phase single stage low-cost inverter for the transfer of direct current (DC) power from the solar photovoltaic (SPV) panel to the grid while meeting the standards for interconnection. The power transfer from SPV to grid is facilitated by controlling the angle between the inverter voltage and the grid voltage i.e. the power angle or phase angle (δ). Simulation of the single stage inverter for a power rating of 500 W is implemented in MATLAB/Simulink. The synchronization of the inverter with the grid was carried out by monitoring the grid frequency continuously and updating it. The power transferred to the grid is made equal to the available power by moni- toring and updating δ. A pulse-width modulation (PWM) control is implemented using PIC16F877 microcontroller for the inverter so as to deliver the available power from the solar panel to the grid, as well as, make the frequency of the output voltage of the inverter equal to the grid frequency for sustaining the synchronization.

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2016

Journal Article

Dr. Vijayakumari A., Devarajan, A. T., and Devarajan, N., “Extraction of photovoltaic (PV) module’s parameters using only the cell characteristics for accurate PV modeling”, Advances in Intelligent Systems and Computing, vol. 397, pp. 265-276, 2016.[Abstract]


This paper presents a method for extraction of the model parameters pertaining to a commercially available PV module, which can be used to develop an accurate PV model that can serve as a source for simulation studies of both grid-connected and stand-alone PV systems. All the physical parameters required for the PV model are determined only from the published V-I characteristics of the module and the standard cell equation. A curve fitting based extraction technique is proposed to obtain the parameters pertaining to a particular PV module available in the market. The extracted parameters are used and a simulation model of the PV module is developed in MATLAB/Simulink. The inputs to the model are irradiance, ambient temperature, number of series and parallel modules in an array as required in an application. A 115 W commercial module S115 is taken for verification, and its physical parameters are extracted and its simulation model is developed. The characteristics of the developed model with the extracted parameters, for several G and TC are presented and compared with the published data of S115 and com- pliance confirmed. The model has been tested for sudden changes in irradiance and temperature using a maximum power point tracker. © Springer India 2016.

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2014

Journal Article

K. Deepthi, Dr. Vijayakumari A., and Joshy, A., “Control of grid connected inverter with PR controller and LCL filter for interfacing renewable energy sources”, Advanced Materials Research, vol. 984-985, pp. 979-989, 2014.[Abstract]


This paper presents a design procedure for Proportional-Resonant (PR) controller and a third order LCL filter which decide the performance of the converter that is used to interface the renewable energy source to the grid. The primary focus of the paper is to evaluate the performance of the controller with the filter for a microgrid application. A scaled down model of microgrid available in the department laboratory is considered for he performance evaluation of the esigned controller. The system is simulated with a 2kVA PWM inverter and tested under onditions such as change in grid impedance, grid frequency and step change in reference current. The simulation results show that the PR controller with LCL filter tracks the reference with zero steady state error and the controller is found to be immune to grid frequency and micro-grid configure tion changes. © (2014) Trans Tech Publications, Switzerland.

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Faculty Research Interest: 
207
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OFFERED
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AMRITA
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GRADE BY
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8th
RANK(INDIA):
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