S. Umashankar

Fuzzy-Based Microgrid Energy Management System Using Interleaved Boost Converter and Three-Level NPC Inverter with Improved Grid Voltage Quality

This paper demonstrates a novel method to integrate and control PV source and Battery storage in to a microgrid system to attain reduction in total harmonic distortion at the output. The closed-loop control of inverter has been achieved through using proportional integral controller (PI) and fuzzy logic controller. The results of output harmonics contents are compared for simple open-loop control and proposed closed-loop controls, and it clearly indicates that the closed-loop results far superior in terms of harmonic contents at the inverter output voltage. The control of battery energy storage system (BESS) has been presented, with the aid of a DC–DC bidirectional buck–boost converter for the different modes of operation, such as hold state, charging state and discharging state. With the intention of tracking the maximum power point from PV array, P&O MPPT technique has been used by which duty cycle of converter is controlled. Various operating conditions, such as photovoltaic source alone supplying to the entire load requirement and supplying to battery for its charging, PV source supplying to load requirement only, battery storage unit supplying to load requirement and lastly PV source and battery storage unit jointly supplying to the load requirement, have been analyzed extensively. Detailed analysis has been carried out on the output voltage, output current and output power waveforms for different operating conditions as discussed above, and the output results are analyzed for achieving more beneficial performance of the system. The suggested microgrid energy management system has been modeled and analyzed using MATLAB/Simulink tool.

Investigations of Microgrid Stability and Optimum Power Sharing Using Robust Control of Grid Tie PV Inverter

This paper demonstrates a novel method to establish robust control and stability of microgrid connected with photovoltaic (PV) grid tie inverter, battery storage with bidirectional inverter, and diesel generator. The proposed control scheme enables optimum power sharing among the sources based on the changes in generation due to intermittent nature of PV source and level of energy stored in battery. Power flow control has been achieved by varying the active power generated by the PV inverter as a function of the system frequency in the islanded mode of operation. Detailed analysis has been carried out in MATLAB/Simulink tool and the captured results are found to effective and same has been confirmed with hardware prototype setup with PV inverter and bidirectional battery charger.

Decoupled Active and Reactive Power Control of Cascaded H-Bridge PV Inverter for Grid-Connected Applications

In a conventional solar power plant, DC input voltage to the inverter is fed from the multiple solar panels with series parallel combination. So the maximum power point tracking (MPPT) is possible only on the series parallel combination of all the arrays together, which is not so efficient. Independent maximum power point tracking (MPPT) is needed to improve the system efficiency. Independent control of the voltage is possible through the cascaded inverters. Hence, independent MPPT control can be obtained by using cascaded H-Bridge-based inverters for PV applications. In this paper, decoupled control of active and reactive powers for a CHB inverter in PV applications is explained and the simulation results are presented. System operation with equal and unequal irradiances on PV arrays is also explained.

Common-Mode Voltage Regulation of Three-Phase SVPWM-Based three-Level NPC Inverter

This paper presents the implementation of the modulation strategy to balance the neutral point potential (NPP) in three-level NPC inverters. This method employs the space vector pulse width modulation technique which gives the strong regulating ability of common-mode voltage of DC link capacitors. Apart from balancing the dc bus voltage this paper also examines the switching losses and junction temperature associated with the three-level inverters. The comparison of three-level inverter with two-level inverter, on the basis of switching losses, has also been explored. The performance of the modulation strategy to balance NPP has been validated and verified using MATLAB/Simulink.

Modeling and Simulation of Synchronous Reluctance Motor for Pumping Application Using Field-Oriented Control

This paper presents field-oriented control (FOC) strategy to improve the performance of a synchronous reluctance motor (SynRM) drive system. In this article, the synchronous reluctance motor is used to drive the centrifugal pump that requires high power density . A mathematical model of SynRM is formed using dynamic equations of the motor. This motor model is then simulated using MATLAB Simulink. The suggested control strategy is reviewed, and its control performances (flux and current along direct and quadrature axes) are analyzed. Simulation results are presented to show the efficacy of the approach.

Investigation of Direct Torque Control-Based Synchronous Reluctance Motor Drive for Pumping

This paper discusses direct torque control (DTC) strategy for a synchronous reluctance motor (SynRM). In this article, the SynRM is used to drive the centrifugal pump that requires high power density. A mathematical model of SynRM is formed using dynamic equations. This motor model is then simulated using MATLAB Simulink. The suggested DTC control is analysed for different speeds, and the results are illustrated. The control strategy is simulated, and its performance parameters (flux and current along direct and quadrature axes) are analysed. Simulation results of the synchronous reluctance motor (SynRM) and pump are presented in this paper to determine the performance of the drive.

Survey of Power Quality Discrete Disturbances in an Educational Institution

There are number of studies based on power quality events, but very few literatures are focused only on the discrete disturbances which also known as events of power quality disturbances. To answer several questions about the discrete disturbances, the power quality survey was conducted at VIT University, India. This survey intended to lay out information related to power quality disturbances mainly focused on swells, dips, transients, rapid voltage changes, voltage interruptions, and other parameters. The result from the survey will give a better knowledge and understanding about the above parameters.

Comparative Analysis of Feed-Forward and Synchronous Reference Frame Control-Based Dynamic Voltage Restorer

The protection of nonlinear and sensitive loads can be achieved economically through series compensation-based dynamic voltage restorer. The effective voltage compensation by dynamic voltage restorer depends on the controller used for voltage sag detection. In this paper, the sag detection of dynamic voltage restorer employing feed-forward control and synchronous reference frame control are compared. The efficiency of sag detection of these controls in dynamic voltage restorer for in-phase compensation of balanced sags with PWM-based injection of compensation voltage is analyzed. Comparisons on the performance of the controllers are shown clearly using Matlab/Simulink-based simulated results.

Experimental Investigation of VFD-Fed Scalar Control of Induction Motor for Pumping Application

In this proposed paper, the experimental results on variable frequency drives (VFDs)-fed pumps are taken out into considerations that are obtained from the laboratory set-up and the modelling done by the author. The simulation study of induction machine using the speed control technique V/F for pumping application is made. To survey the drive performance, VFDs manufactured by Danfoss, with their own control system is used as a special planned simulator. The aim of this paper is to compare and evaluate the results taken out in laboratory and MATLAB/Simulink for an effective pumping system. The simulation and experimental results shown in the article are used to determine the performance of pumping system.

Solar PV-Based VFD Fed Permanent Magnet Synchronous Motor for Pumping System

This paper determines the incorporation of photovoltaic source and battery with a PMSM motor fed with a centrifugal pump based on conventional Direct Torque Control technique (DTC). For the boosting of solar output, interleaved DC-DC converter with fuzzy logic-based MPPT control is studied and in order to convert the DC output of converter for the required form of motor input, three-phase inverter has been taken. With the help of a bi-directional converter, regulation of battery is carried out which depends on load and source. Output results of motor as well as pump are obtained using MATLAB Simulink environment.