Ahmad Asri Abd Samat

Identification of Hammerstein-Weiner System for Normal and Shading Operation of Photovoltaic System

This paper present an identification of model system performance for Photovoltaic (PV) System under normal and shading operating condition in UiTM Pulau Pinang, Malaysia of 2.4 kW systems. A system identification approach was implemented by employing a Hammerstein-Weiner (HW) model as model structure. The approach concerned on the estimation of the photovoltaic system basis of observed data. The nonlinearity input and output are taken from irradiance and dc output current data of the real system severally. These data were used in Hammerstein-Weiner model to generate a black-box model structure which provides a flexible parameterization for nonlinear models. The best fit nonlinear model when using data from normal operating condition is when HW model incorporate with piecewise linear as the input channel and wavelet network estimators as output channel. For normal operation of PV system, the percentage of best fit was 96.51% by means of bn = 1, fn = 3, and kn = 2 of the linear model order. While the percentage best fit model generate considering shading effect was 86.32% with bn = 1, fn = 3, and kn = 1 of the linear model order. The modelling is implemented using system identification toolbox of Matlab software package.

Identification of Multiple Input-Single Output (MISO) model for MPPT of Photovoltaic System

This paper presents a modelling of Multiple Input-Single Output (MISO) model for tracking maximum point of Photovoltaic (PV) Systems. A system identification approach is used to obtain the model characteristics of existing structural systems through dynamic observations which incorporate with traditional direct control Maximum Power Point Tracking (MPPT) algorithm. The generate model characteristics was used in designing the MPPT of the Photovoltaic Systems. The need of an efficient mathematical model to characterize the dynamics system for PV is essential for implementing the system for control applications. In this paper, the transfer function relating the input parameters (Solar irradiance and cell temperature) and output parameter (DC current) of the PV module MF120EC3 was identify with the aid of MISO for Auto-Regressive with eXogenous input (ARX) model. The approach has concern on the estimation of the (Direct Current (DC) for photovoltaic system based on the real systems data from Pusat Tenaga Malaysia (Malaysia Energy Centre, MEC). A Fourth-order autoregressive (ARX) model using the ARX algorithm, (ARXQS) was chosen since the model output provide 93.42% best fit model criteria. The modelling is implemented using system identification toolbox of Matlab software.

Speed- sensorless control of parallel- connected PMSM fed by a single inverter using MRAS

This paper present the speed sensorless Field Oriented Control (FOC) of parallel- connected dual permanent magnet synchronous motor (PMSM) fed by a single inverter. The speed for both motors are estimated by using Model Reference Adaptive System (MRAS) scheme. In this scheme, two different models are used which are reference model and adjustable model. The motor is set to be a reference model and the current is set to be an adjustable model. Speed is control by using FOC method. The simulation work is implemented in Matlab/Simulink software to verify the control method. The effectiveness of this proposed control method was confirmed through different balanced and unbalanced loads and speed.

Comparison between PSO and FLC: MPPT for Energy Harvesting of PV System under Partial Shading Condition

Conventional Maximum Power Point Tracking (MPPT) controllers are widely used due to simple implementation and show a good performance in tracking Maximum Power Point (MPP) when solar irradiance is uniform. However, when partial shading occurs on the PV array, tracking to MPP becomes complicated as multiple peaks exist on the Power-Voltage (P-V) characteristic curve. Several methods based on stochastic algorithm and artificial intelligence has been developed to track true MPP under partial shading conditions. This paper focuses on the performance of MPPT controller to extract maximum power from PV system under partial shading condition. The selected MPPT algorithms that have been implemented in the PV system include Fuzzy Logic Controller and Particle Swarm Optimization. Results show that both the simulated MPPT controllers are capable of tracking the maximum power.

Implementation of Sugeno FIS in model reference adaptive system adaptation scheme for speed sensorless control of PMSM

Model reference adaptive system (MRAS) is one of the popular methods to observe the speed and the angle information of the Permanent magnet synchronous motor (PMSM). This paper proposes a new adaptation scheme for MRAS to replace the conventional PI controller based on Popov Hyperstability theorem. In this project, the speed of PMSM is controlled by using field oriented control (FOC) method and the MRAS is used to observe the speed and the rotor position of the motor. The reference model for the MRAS is the PMSM itself while the adjustable model is the current model in the rotor reference frame. The Sugeno Fuzzy Logic Inference System (FIS) is implemented in the adaptation scheme in order to tune the error between the reference and the adjustable model. The new proposed method shows it is capable to track the motor speed efficiently at wide range of operating speeds.

New model of inverting substation for DC traction with regenerative braking system

This paper presents a power electronic devices application focus on modeling, analysis, and control of switching power converter in the inverting DC substation with regenerative braking system which is used to recycle the surplus regenerative power by feed it back to the main AC grid. The main objective of this research is to improve the switching power electronic converter of the railway inverting substation and optimize the maximum kinetic energy recovery together with minimum power losses from the railway braking system. Assess performance including efficiency and robustness will be evaluated in order to get the best solution for the design configuration. Research methodology included mathematical calculation, simulation, and detail analysis on modeling of switching power converter on inverting substation. The design stage separates to four main areas include rectification mode, regenerative mode, control inverter mode and filtering mode. The simulation result has shown that the regenerative inverter h...

Application of Artificial Bee Colony Algorithm for Distribution Network Reconfiguration

—Network reconfiguration is a process of changing the original structure of the distribution network system with the intention of balancing the load in every system’s feeder at the same time to optimize the operation of the system. The process involve the changing of switching state (tie switches and sectionalize switches), with the aim to find the best combination that can increase the performance of the system while satisfying with the operational constraints. The extreme necessity to the process has become a challenging mission for the researcher to overcome the reconfiguration problems. Recent years have seen a rapid development of evolutionary algorithms and swarm intelligence based algorithms to resolve for network reconfiguration problems. For that reason, this report deals with Artificial Bee Colony (ABC) algorithm to be implemented in network reconfiguration procedure to achieve the optimum level of operation. The ease and simplicity of the algorithm and the capability to find the global optimization solution has made this algorithm appropriate for this project. The objective of this work focused on improvements of distribution power system, in terms of minimizing the total real power loss and improving the voltage profile within the acceptable value. The algorithm was tested on two different radial distribution system (33 bus and 69 bus radial distribution systems)

Comparison between Takagi Sugeno FIS and PI Controller: An Adaptation Scheme of MRAS for Speed Sensorless Control of PMSM

— This paper proposes modification of an adaptation scheme which aims to replace the conventional PI controller for MRAS by using Fuzzy Logic Control (FLC). This FLC based on Takagi-Sugeno Fuzzy Logic Inference System (FIS). To achieve this goal, field oriented control (FOC) method has been utilized to control the speed of PMSM with the implementation of MRAS to observe the rotor position and speed of the motor. PMSM becomes the reference model for MRAS while the current model in the rotor reference frame is set as the adjustable model. The Takagi Sugeno Fuzzy FIS is executed in the MRAS adaptive scheme in order to tune the errors between the reference and adjustable model. The effectiveness of the Takagi Sugeno FIS to tune the errors in MRAS scheme is compared with the conventional PI controller. The proposed method clearly indicates improved motor performance over a wide range of operating speeds since is capable of tracking the motor speed effectively.

A Phase Shifting Technique for Harmonic Reduction in Modern Electrical Distribution Systems

A conventional electrical distribution system are not designs to deal with harmonics because at that time the linear load conquer the consumer demand. Over the years with growing use of nonlinear load such as personal computer can contribute to harmonics current occur on electrical distribution system. With the presence of harmonics current on electrical distribution system leads in degradation of system performance. Therefore necessary actions are needed in order to minimize harmonics effect. The predominant harmonics should be eliminated from electrical distribution system such as 5th and 7thof harmonics current component. The eliminating process is achieved by implementing the current phase shifting technique on new concept of modern electrical distribution system at Makmal Komputer 3, Faculty of Electrical Engineering, UiTM Pulau Pinang.

Harmonic reduction using current injection based twelve-pulse rectifier

A twelve-pulse rectifier structure will apply the current injection method which automatically generated in order to reduce the total harmonic distortion (THD) for the three-phase diode rectifier. The twelve pulse operation applying of three-phase diode rectifier, two additional diode, two transformers with low VA rating and simple zig-zag transformer will be designed to achieve the low THD. The losses in the current injection system considerably affect the input current THD and volt-ampere ratings of applied magnetic circuit. The zig-zag transformers are used as a current injection device to provide low-leakage impedance for the current harmonics generated, resulting in pure sinusoidal input current in the three-phase diode bridge rectifier.