Alivelu M. Parimi

Implementation of MPPT control using fuzzy logic in solar-wind hybrid power system

The renewable energy sources such as Solar energy and Wind energy are complementary by nature. Utilizing these natural resources to produce power will reduce the power demand on the conventional power generation sector. One of the applications of Solar-Wind hybrid power system (SWHPS) is to reduce the amount of power consumed from the conventional power generation to charge the storage reserves present in the system. The SWHPS comprises of Photovoltaic array, wind turbine, Permanent Magnet Synchronous generator (PMSG), controller and converter. The efficiency of the SWHPS depends on the MPPT controller, which makes the Photovoltaic (PV) and wind power generation system to operate at its maximum power. In PV system Perturb & Observe (P&O) algorithm is used as control logic for the Maximum Power Point Tracking (MPPT) controller and Hill Climb Search (HCS) algorithm is used as MPPT control logic for the Wind power system in order to maximizing the power generated. This paper presents a comparative analysis of MPPT controller built using P&O for PV system and HCS for Wind power system, with MPPT controller implemented using Fuzzy Logic control (FLC) in the both the renewable sources in the hybrid system. The performance of the different implementation of MPPT controllers in the hybrid system are investigated in this paper in MATLAB, Simulink. The SWHPS with the FLC based MPPT has shown to have a better, faster control as compared with the other controllers.

Interline Power Flow Controller (IPFC) based damping controllers for damping low frequency oscillations in a power system

The interline power flow controller (IPFC) is a voltage-source-converter (VSC)-based flexible AC transmission system (FACTS) controller which can inject a voltage with controllable magnitude and phase angle at the line-frequency thereby providing compensation among multiple transmission lines. In this paper, the use of the IPFC based controller in damping of low frequency oscillations is investigated. An extended Heffron-Phillips model of a single machine infinite bus (SMIB) system installed with IPFC is established and used to analyze the damping torque contribution of the IPFC damping control to the power system. The potential of various IPFC control signals upon the power system oscillation stability is investigated a using controllability index. Simulation results using Matlab Simulink demonstrate the effectiveness of IPFC damping controllers on damping low frequency oscillations.

Damping of inter area oscillations using Interline Power Flow Controller based damping controllers

This paper investigates the effect of interline power flow controller (IPFC), an advanced flexible AC transmission system (FACTS) controller, in damping low frequency oscillations via supplementary control. For this purpose, a modified linearised Phillips-Heffron model for a single machine infinite bus (SMIB) system installed with IPFC is established, and the power oscillation damping controller is designed. The effect of this damping controller on the system, subjected to wide variations in loading conditions and system parameters, is investigated. Results of simulation investigations in Matlab are presented to validate the proposed approach.

Performance Analysis of a Two-Diode model of PV cell for PV based generation in MATLAB

The increase in concern for carbon emission and reduction in natural resources for conventional power generation, the renewable energy based generation such as Wind, Photovoltaic (PV), and Fuel cell has gained importance. Out of which the PV based generation has gained significance due to availability of abundant sunlight. As the Solar power conversion is a low efficient conversion process, accurate and reliable, modeling of solar cell is important. Due to the non-linear nature of diode based PV model, the accurate design of PV cell is a difficult task. A built-in model of PV cell is available in Simscape, Simelectronics library, Matlab. The equivalent circuit parameters have to be computed from data sheet and incorporated into the model. However it acts as a stiff source when implemented with a MPPT controller. Henceforth, to overcome this drawback, in this paper a two-diode model of PV cell is implemented in Matlab Simulink with reduced four required parameters along with similar configuration of the built-in model. This model allows incorporation of MPPT controller. The I-V and P-V characteristics of these two models are investigated under different insolation levels. A PV based generation system feeding a DC load is designed and investigated using these two models and further implemented with MPPT based on P&O technique.

Fuzzy logic control for IPFC for damping low frequency oscillations

This paper presents the application of fuzzy logic based supplementary controller, for Interline Power Flow Controller (IPFC), to enhance the damping of low frequency oscillations in the Single Machine-Infinite Bus (SMIB) power system installed with IPFC. The fuzzy logic based IPFC controller using Mamdani type inference system is designed with generator speed and rotor angle as its input signals. The proposed method is applied to control the input signal of IPFC and thus improving the power system stability. The effectiveness of the controller in damping the power system oscillations is demonstrated with varying operating conditions.

Investigation of small PMSG based wind turbine for variable wind speed

In order to investigate small wind turbines, a comprehensive knowledge of mechanical and electrical parameters is required. Permanent Magnet Synchronous Generator (PMSG) is one of the kinds which are widely used for variable speed and direct driven wind power generating. In order to predict the amount of power that can be extracted by the wind turbine in a concerned area the knowledge of wind speed pattern for that particular location is required. In this paper a case study is selected to study the wind pattern and investigate the performance of the PMSG based wind power generation system for fixed speed and variable speed conditions. Wind power generation system simulated using MATLAB / Simulink consisting of wind turbine, PMSG, diode rectifier, Maximum Power Point tracking (MPPT) controlled boost converter, and DC load is considered. The Hill Climbing Search (HCS) algorithm is implemented using Fuzzy Logic Controller (FLC) for MPPT. The effectiveness of PMSG based wind power generation in the case study is investigated with the environmental conditions recorded at BITS-Pilani, Hyderabad campus, Telangana, India.

Comparing the performance of IDVR for mitigating voltage sag and harmonics with VSI and CSI as its building blocks

Power system is broadly divided into three stages, generation, transmission and distribution. There are several challenges in each stage which are needed to be addressed. This paper concentrates on the challenges in distributed systems called power quality. Power quality improvement is a major concern in the distributed system. There are several power quality problems like voltage sag, harmonics, flickering, distortions etc. Two major problems considered in this paper are the voltage sag and harmonics. To handle with these power quality problems Flexible AC Transmission Systems (FACTS) devices are utilized. Interline Dynamic Voltage Restorer (IDVR) is proposed to eliminate the voltage sag and harmonics. The major aspect of IDVR is being able to replenish energy to the DC link while injecting required voltage in more than one power line unlike the Dynamic Voltage Restorer (DVR). The building blocks of IDVR used for injecting the voltage can either be voltage source inverter (VSI) or current source inverter (CSI). An IEEE 8 bus system is considered, consisting of generation, transmission and distribution levels. The sensitive loads are assumed to be connected at the distribution side The IDVR is installed near the distribution side. The performance of the IDVR in reducing voltage sag and harmonics as its building block either VSI or CSI is investigated and compared in this paper in MATLAB environment.

Dynamic modeling of Interline Power Flow Controller for small signal stability

This paper addresses the formulation of the nonlinear dynamic model of the power system installed with Interline Power Flow Controller (IPFC). The linearized model for both single-machine infinite-bus and multi-machine power system installed with IPFC is developed and incorporated into the Phillips-Heffron model. These models lay the foundation for small signal stability studies of the power system using IPFC. The application of the models is demonstrated for a Multi-machine power system.

Mitigation of supply & load side disturbances in an AC Microgrid using UPQC

The importance of Microgrid concept is increasing extensively and more number of microgrids will be installed at consumer premises in the coming future. The penetration of distributed generation (DG) units consisting different loads makes microgrids suffer from power quality and power control issues. Some of them are voltage stability, swells and sags, and power factor improvement which require reactive power. In particular, microgrid in islanded mode has to maintain the power balance independently of a main grid due to lack of infinite bus as generation and consumption are tightly coupled. Due to versatile loading conditions, even in grid connected mode reactive power compensation is becoming a challenging task. Hence the key objective of this paper is to investigate reactive power compensation in microgrids. In this regard, new techniques and devices for VAR compensation in the micro grid are being investigated. The device considered in this paper is Unified Power Quality Conditioner (UPQC). Initially UPQC is modeled, simulated and tested in conventional distribution power system. Later the same is incorporated into the microgrid. The microgrid is developed with two DG units, a PV generator and a wind generator to give an output voltage equal to the conventional 3 phase 4 wire distribution system. The performance of the UPQC with its control technique in providing the reactive power compensation to resolve the power quality issues in microgrid with dynamically varying load is examined.

Application of Dynamic Voltage Restorer in microgrid for voltage sag/swell mitigation

Microgrids are becoming increasingly attractive to consumers as it allows utilization of freely available renewable energy sources. They are usually installed at consumers sites i.e the distribution end. Due to high penetration of distributed generation units with different types of loads, microgrids can cause power quality and power control issues. Some of them are voltage swells and sags, and low power factor which further require reactive power compensation. This paper presents the utilization of the custom power device specifically Dynamic Voltage Restorer (DVR) in mitigating the problem of voltage sags and swells occurring in microgrid. A microgrid is modeled and simulated with different loading conditions causing power quality problems. The performance of DVR, installed in microgrid, is analyzed for reactive power compensation to overcome these concerned issues. The control logic of DVR is designed using phase locked loop (PLL) technique and its effectiveness is observed in Matlab/Simulink.