Browsing by Author "Koothu Kesavan, K.K."

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A Novel Algorithm Based on Voltage and Current Perturbation to Track Global Peak Under Partial Shading Conditions
(Institute of Electrical and Electronics Engineers Inc., 2022) P, P.; Vignesh Kumar, V.; Koothu Kesavan, K.K.; Balasubramanian, B.
Under partial shading conditions, photovoltaic (PV) systems exhibit multiple peaks in their power-voltage (P-V) characteristics. It is essential to extract maximum energy from the PV system. The global maximum power point tracking (GMPPT) algorithms presented in the literature, track the global peak using different methods. It is imperative to have minimal convergence time for GMPPT process. This paper proposes a novel algorithm to track the global peak using voltage and current perturbation. The new GMPPT algorithm operates in a current perturbation or voltage perturbation mode, based on the value of a control variable. In either mode, the proposed technique generates reference current or reference voltage, for navigating the operating point to GMPP location. The proposed algorithm is compared with two GMPPT algorithms, namely, modified maximum power trapezium (M-MPT) and high-performance GMPPT algorithms. The simulation studies are performed in MATLAB and is validated using a laboratory prototype, with dSPACE 1202 MicroLabBox controller for implementing GMPPT methods. Simulation and experimental results show that the new technique exhibits superior performance in terms of tracking time. Also, the energy efficiency is improved by 40% while using the proposed GMPPT algorithm for the irradiance profiles considered in this paper compared to the other two techniques. © 1986-2012 IEEE.
An Efficient Pseudo-Derivative-Feedback-Based Voltage Controller for DVR Under Distorted Grid Conditions
(Institute of Electrical and Electronics Engineers Inc., 2021) Krishna, D.G.A.; Karthikeyan, K.; Koothu Kesavan, K.K.; Kumar, S.
Grid integration of distributed energy resources has become a technical challenge in the distribution network operation due to the intermittent nature of renewable energy sources and their impact on grid voltage stability. Thus, a dynamic voltage restorer (DVR) is installed in the distribution network system to reduce such grid voltage impact on sensitive loads. In this article, a pseudo-derivative-feedback (PDF)-based voltage controller is implemented for the effective operation of DVR under voltage disturbances. Response of DVR primarily depends upon its controller action. This article addresses the issues in conventional P and PI multiloop controller with and without feedforward path then proposes PDF control strategy for DVR. Using the proposed controller, dynamic performance of DVR is improved. The efficacy of the proposed controller is illustrated by a comparative study with conventional P and PI controller using time response and relative stability analysis. Finally, PSCAD simulation studies for a 10 kV medium voltage DVR and experimental results using a low voltage laboratory prototype DVR are presented to prove the robustness of proposed controller for DVR under symmetric and asymmetric voltage sags. © 2020 IEEE.
Critical review of PV grid-tied inverters
(MDPI AG indexing@mdpi.com Postfach Basel CH-4005, 2019) Kavya Santhoshi, B.K.; Mohanasundaram, K.M.; Padmanaban, S.; Holm-Nielsen, J.B.; Koothu Kesavan, K.K.
Solar Photovoltaic (PV) systems have been in use predominantly since the last decade. Inverter fed PV grid topologies are being used prominently to meet power requirements and to insert renewable forms of energy into power grids. At present, coping with growing electricity demands is a major challenge. This paper presents a detailed review of topological advancements in PV-Grid Tied Inverters along with the advantages, disadvantages and main features of each. The different types of inverters used in the literature in this context are presented. Reactive power is one of the ancillary services provided by PV. It is recommended that reactive power from the inverter to grid be injected for reactive power compensation in localized networks. This practice is being implemented in many countries, and researchers have been trying to find an optimal way of injecting reactive power into grids considering grid codes and requirements. Keeping in mind the importance of grid codes and standards, a review of grid integration, the popular configurations available in literature, Synchronization methods and standards is presented, citing the key features of each kind. For successful integration with a grid, coordination between the support devices used for reactive power compensation and their optimal reactive power capacity is important for stability in grid power. Hence, the most important and recommended intelligent algorithms for the optimization and proper coordination are peer reviewed and presented. Thus, an overview of Solar PV energy-fed inverters connected to the grid is presented in this paper, which can serve as a guide for researchers and policymakers. © 2019 by the authors.
Development of Small Signal Model and Stability Analysis of PV-Grid Integration System for EV Charging Application
(Institute of Electrical and Electronics Engineers Inc., 2024) Kanimozhi, K.; Koothu Kesavan, K.K.; Nagendrappa, N.; Balasubramanian, B.
In this article, grid interactive photovoltaic (PV) system is designed for an electric vehicle (EV) charging application, and the stability of the system is analyzed. The small signal model for the system is derived by averaging and linearizing the state space equations, and the condition for stable operation of PV-integrated charger system is identified from the transfer functions. The proposed charger system implements a coordinated control between the converters to maintain a power balance between the sources and load. System stability is examined using root-locus plots and in addition, the controller is designed to improve the overall stability and reliability of the system. The proposed method provides a general framework for modeling EV charging systems which also details the importance of deriving the model with multiple energy sources. Further, proposed topology has bidirectional capability, which transfers excess PV power to the grid during off-charging hours. The efficacy of the proposed method is verified using the MATLAB Simulink environment for the different scenarios, i.e., variation in the irradiation and disturbances in the grid voltage. The experimental study is conducted on a 1.5-kW laboratory prototype using a low-cost digital signal processing controller (launchpad TMS320F28027F) and the measured results authenticate the simulation findings. © 2020 IEEE.
Electromagnetic torque-based model reference adaptive system speed estimator for sensorless surface mount permanent magnet synchronous motor drive
(Institute of Electrical and Electronics Engineers Inc., 2020) Koothu Kesavan, K.K.; Karthikeyan, A.
This article proposes simple and robust electromagnetic torque-based model reference adaptive system speed estimator with cascaded pseudoderivative feedback controller for sensorless surface mount permanent magnet synchronous motor (SMPMSM) drive to improve its performance at standstill and low-speed regions. The proposed estimator is formed using instantaneous and estimated electromagnetic torque. Using small signal modeling, the stability and sensitivity analysis are performed. Results show that the estimator is stable over a wide speed region (including low-speed regions) and exhibits robustness against uncertainties in machine parameters. The proposed estimator is implemented for the 1.5-kW laboratory prototype SMPMSM drive using field programmable gate array (FPGA) ALTERA Cyclone II. Experimental results demonstrate the efficacy of the proposed scheme under different test conditions viz., over a wide adjustable speed range which includes different low-speed regions and standstill, i.e., 157 to -157 rad/s at different load conditions with uncertainty in machine parameters. © 1982-2012 IEEE.
Four quardrant operation of direct torque controlled PMSM drive using speed loop PDFF controller
(Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Koothu Kesavan, K.K.; Nagamani, C.
This paper presents a comprehensive evaluation of proposed speed loop pseudo derivative feedforward (PDFF) controller based DTC, speed loop PI based direct torque controller (DTC) and speed loop PI based hysteresis current controller (HCC) for permanent magnet synchronous motor (PMSM) drive. The proposed controller reduces the torque and stator current ripples and significantly reduces overshoot and oscillation in the actual rotor speed. The proposed controller is verified for different cases viz., forward and reverse motoring, forward and reverse braking operation. The simulations are carried out through MATLAB/Simulink for 1.2 hp PMSM drive and results demonstrates the efficacy of the proposed controller. Â© 2018 IEEE.
Hybrid Control of Single-Phase to Three-Phase Reduced Switch Converter for PMSM Drive
(Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Varsha, S.; Koothu Kesavan, K.K.
This paper proposes hybrid control for single phase to three phase reduced switch converter based PMSM drive that can be used in remote locations where only single phase grid is available. PI, hybrid (hysteresis+ PI) controllers are employed for controlling the input and output sides of the converter respectively. This configuration for PMSM drive has a shared leg between output and input sides. The input side PI controller synchronizes input grid current with the grid voltage to maintain unity power factor during load and speed variations. This configuration has unity input power factor and allows bidirectional power flow. The proposed system is modeled for 400W motor in MATLAB/SIMULINK environment and the simulation results are presented. Â© 2018 IEEE.
Pseudo derivative feedback current controlled sensorless PMSM drive with flux-Torque based MRAS estimator for low speed operationestimator for low speed operation
(Institute of Electrical and Electronics Engineers Inc., 2017) Karthikeyan, A.; Koothu Kesavan, K.K.; Venkatesa, P.B.; Nagamani, C.
In this paper, a simple and robust speed estimator and Pseudo Derivative Feedback (PDF-PDF) controller are proposed for sensorless PMSM drive to improve its performance at standstill and low speed regions. The speed estimator is formed using stator flux and electromagnetic torque based model reference adaptive system, which performs better during transient conditions and reduces steady state error for wide rotor speed variations which includes low speed regions. The proposed PDF-PDF controller reduces the overshoot and improves settling time of the system. The stability of the proposed estimator is verified through small signal model and the machine parameter sensitivity is also analyzed. The performance of the proposed estimator and controller is validated by considering variation in the low speed regions which includes standstill condition. The simulations are carried out through MATLAB/Simulink and it is also experimentally verified through FPGA controller based 1.2hp laboratory prototype PMSM drive. It is found that the maximum estimated rotor speed and position error are Â±2 rad/s and Â±1Â° respectively during low speed operation at transient and steady state conditions. Â©2017 IEEE.
PV fed Hybrid Power Converter for rural home applications
(Institute of Electrical and Electronics Engineers Inc., 2019) Karthikeyan, A.; Praneeth, C.V.S.; Koothu Kesavan, K.K.
This paper proposes a standalone PV fed hybrid power converter for rural home applications. The aim of the proposed system is to simultaneously deliver the power extracted from PV panels to DC and AC home loads using the proposed hybrid converter topology. The system operates in either MPP or Non-MPP mode depending on the total power demanded by the loads. Modified Perturb and Observe (PO) MPPT algorithm is used to extract maximum power from PV panels. SPWM based modified PWM technique is used for converter operation. In the MPP mode the power distribution to DC load and AC load is in accordance with the duty generated by modified MPPT. In Non MPP mode, power distribution is in accordance with the duty generated by the single loop voltage control for DC load. The simulation studies for the proposed system are carried out in MATLAB/SIMULINK environment. Â© 2019 The Korean Institute of Power Electronics (KIPE).
Single stage PV fed reduced inverter based PMSM for standalone water pumping application
(Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Koothu Kesavan, K.K.; Varsha, S.; Venkatesa Perumal, B.; Mishra, S.
This paper proposes a standalone PV fed PMSM drive for water pumping. The proposed system aims at reducing the switching losses and overall cost by using reduced switch inverter. The proposed system comprises of a PMSM drive, fed by PV source through an inverter employing reduced number of switches. The inverter uses only four switches whereas the conventional VSI utilizes six switches. Field oriented control scheme is employed to control the PMSM drive. Perturb and Observe (PO) MPPT technique is used to generate a speed reference to PMSM drive. Simulation studies for the proposed PV fed 400 W PMSM driven water pumping system are performed using MATLAB platform and respective results are presented to show the efficacy of the system. Â© 2018 IEEE.
Single-stage PV-powered boost inverter-fed permanent-magnet synchronous motor-driven water-pumping system
(Oxford University Press, 2022) Koothu Kesavan, K.K.; Sunkara, V.; Karthikeyan, A.
In this paper, a photovoltaic (PV) fed boost inverter-based permanent-magnet synchronous motor (PMSM)-driven water-pumping system for stand-alone applications is proposed. The proposed system comprises PV panel, six switches, three inductors (L), three capacitors (C) and a water pump. In this work, the boost inverter is designed with a gain of two and thereby the direct current input required to run the motor is considerably reduced. Hence, the size of the system is reduced. The voltage gain factor depends upon the placement of the L and C components and their values. The speed reference is generated using a perturb and observe maximum power point tracking algorithm. Vector control is employed to control a boost inverter-fed PMSM drive. The proposed system is simulated using a MATLAB®/Simulink® environment and experimental validation is performed on a PMSM laboratory prototype using a field programmable gate array controller. The simulation and experimental results demonstrate the effectiveness of the proposed system. © 2022 The Author(s). Published by Oxford University Press on behalf of National Institute of Clean-and-Low-Carbon Energy.
Speed loop pseudo derivative feedback controller based direct torque controlled permanent magnet synchronous motor drive
(Institute of Electrical and Electronics Engineers Inc., 2017) Koothu Kesavan, K.K.; Venkatesa Perumal, B.V.; Karthikeyan, A.; Nagamani, C.
This paper presents a comprehensive evaluation of PI controller and proposed pseudo derivative feedback (PDF) controller based direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drive. The proposed controller eliminates oscillation and overshoot in the actual rotor speed and significantly reduces the flux, torque and stator current ripples. The performance of the proposed controller is tested for different cases viz., no load starting response, load variations at rated speed, wide speed reversal and low speed regions including standstill condition at rated torque. The simulations are carried out through MATLAB/Simulink environment for 1.2hp PMSM drive and results demonstrates the efficacy of the proposed controller. Â© 2016 IEEE.
Standalone single stage PV fed reduced switch inverter based independent control of two PMSM drive
(Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Koothu Kesavan, K.K.; Abhilash Krishna, D.G.; Nagamani, C.
This paper proposes a standalone singe stage PV fed air cooler which consists of two motors (fan blower and water pump). The proposed system comprises of PV source, reduced switch inverter and two PMSM drive. The proposed system aims at reducing the switching losses and overall cost by using reduced switch inverter. The reduced switch inverter uses only eight switches whereas the conventional VSI utilizes twelve switches. In the proposed scheme, blower and pump are independently controlled using field oriented control scheme where speed reference is obtained using Perturb and Observe (PO) technique. Simulation studies for the proposed PV fed two 400 W PMSM driven blower and pump is performed using MATLAB platform and respective results are presented to show the efficacy of the system. Â© 2018 IEEE.
Standalone Single Stage PV-Fed Reduced Switch Inverter Based PMSM for Water Pumping Application
(Institute of Electrical and Electronics Engineers Inc., 2020) Koothu Kesavan, K.K.; Karthikeyan, A.; Varsha, S.; Venkatesa Perumal, B.V.; Mishra, S.
This article proposes a standalone single stage photovoltaic (PV) fed reduced switch inverter (RSI) based permanent magnet synchronous motor (PMSM) drive for water pumping application. The proposed system aims at reducing the switching losses and overall cost by using reduced switch inverter. The proposed system comprises a PMSM drive, fed by PV source through an inverter employing reduced number of switches. The inverter uses only four switches whereas the conventional voltage source inverter utilizes six switches. Field oriented control scheme is employed to control the PMSM drive. Perturb and observe maximum power point tracking technique is used to generate a speed reference to PMSM drive. The proposed system is simulated using MATLAB/Simulink platform, and it is also experimentally verified with field programmable gate array (FPGA) controller based 400 W laboratory prototype PMSM drive. The simulation and experimental results demonstrate the efficacy of the proposed system. © 1972-2012 IEEE.
Stator flux based MRAS speed and stator resistance estimator for sensorless PMSM drive
(Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Koothu Kesavan, K.K.; Nagamani, C.
In this paper, a simple and robust speed and stator resistance estimator is proposed for sensorless permanent magnet synchronous motor drive to improve its performance at standstill and low speed regions. The speed and stator resistance estimator is formed using stator flux based model reference adaptive system, which yields fast transient response, reduces steady state error for low rotor speed variation and load disturbances. The proposed method improves the performance of the drive at low speed regions. The simulations are carried out through MATLAB/Simulink environment and results show the effectiveness of the sensorless PMSM drive. The maximum estimated rotor speed and position error are found to be are Â±3 rad/s, Â±1 Â°respectively, during low speed operation at transient and steady state conditions. Â© 2017 IEEE.
Uncertainity and disturbance estimator based control of transformerless DVR
(Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Abhilash Krishna, D.G.; Kurra, S.; Koothu Kesavan, K.K.
This paper presents Uncertainty and Disturbance Estimator (UDE) based control for Transformerless Dynamic Voltage Restorer (TDVR). The proposed UDE based control algorithm for TDVR mitigate the voltage disturbances and maintain robustness during parameter (filter) variations. The control equation of UDE is derived based on the dynamic model of a voltage source inverter along with the LC filter. The proposed UDE control estimates the uncertainties and disturbances by an appropriate filter (loop filter involved in the derived UDE control law) and used for further synthesis, thus accounts for robustness. The simulation studies are performed for 230 V low voltage (LV) system in MATLAB to verify the efficacy of UDE control for symmetric and asymmetric voltage sags along with the parameter mismatch (inverter filter) conditions. Â© 2018 IEEE.