Ahmad Maliki Omar

Modeling and simulation of Photovoltaic (PV) array and maximum power point tracker (MPPT) for grid-connected PV system

In this paper a validated, generic and user-friendly PV array and MPPT models are presented in the mathematical modeling and circuit-based approach. The PV array model accepts irradiance and temperature as variable parameters and outputs I-V and P-V characteristics. The Hill Climbing (HC) algorithm is implemented to track the maximum power point (MPP). The model is validated against data obtained from an installed PV system at Malaysia Green Technology Corporation (MGTC) in Bangi, Selangor, Malaysia with installed capacity of 47.28 kWp. From the comparison of the simulated results with that of the MGTC, it clearly shows that power produced in simulation is higher than the actual. This is due to some factors itemized in this work.

Implementation of Single-Phase Matrix Converter as a Direct AC-AC Converter Synthesized Using Sinusoidal Pulse Width Modulation with Passive Load Condition

The aim of this paper is to describe work involved in investigations on the implementation of the Single-Phase Matrix Converter (SPMC) as an AC-AC converter subjected to passive load conditions. The output voltage was synthesized using the well-known Sinusoidal Pulse Width Modulation (SPWM). A Xilinx Field Programmable Gate Array (FPGA) was used to implement the controlling algorithm with IGBTs as power switching device. Prior to hardware implementation, simulations were performed to predict the behaviour. A laboratory model test-rig of the SPMC was then developed to experimentally verify the result. Good agreement was obtained between simulation and laboratory experiments.

A modification of variable step size INC MPPT in PV system

The fixed step maximum power point tracking (MPPT) is extensively applied due to simple and easy to execute. This paper presents variable step size (VSS) applied to MPPT to improve tracking speed and accuracy. Nevertheless, there are drawbacks in conventional VSS between time response and power oscillation. A modified VSS using incremental conductance (INC) algorithm technique is proposed which solve the trade-off between time response and power oscillation. The proposed method is implemented using PIC18F4520 and verified experimentally.

A review of single-phase single stage inverter topologies for photovoltaic system

This paper discussed the latest development of single-phase single stage current source inverters for grid connected photovoltaic system. In general, the single-phase single stage inverters are categorized into four types of topologies: 1) H-Bridge, 2) buck-boost, 3) flyback type chopper and 4) Z-Source inverter. The inverters are compared and evaluated on switching technique, switching frequency, efficiency, output power, MPPT method, power factor and THD.

Performance of Grid-Connected Photovoltaic System in Equatorial Rainforest Fully Humid Climate of Malaysia

Received Jan 3, 2013 Revised Jul 1, 2013 Accepted Jul 16, 2013 This paper presents a result obtained from a comparative study of three different photovoltaic (PV) module technologies for grid-connected (GC) system under Malaysia’s operating conditions. From the results obtained, the performance ratio (PR) showed slightly different from the three PV technologies for polycrystalline was about 78.2%, 94.6% for a-Si thin film and 81% for monocrystalline during the four years of monitoring. Outdoor assessment shows that a-Si thin-film PV modules had demonstrated high performance and better in terms of final yield, performance ratio and array/system efficiency of the GC system over the entire monitored period. On the other hand, a-Si thin-film PV modules exhibit higher energy production, reliability and better conversion of system performance in Malaysia. Keyword:

Design of data logger with multiple SD cards

This paper describes the design of general data logger system which is able to store data from few input channels and having large memory space. The proposed data logging system is aimed to be able to store plenty quantities of data from analog signal over an extensive period of time so that it will be able to be left unattended for a quite long time. Besides the communication between microcontroller and memory unit are discussed in detail in this paper. The limitation of memory storage is also tested. A prototype of data logger is developed and tested to verify the concept mentioned before.

Power prediction for grid-connected photovoltaic system in Malaysia

This paper presents the prediction performance and analysis of the power output from grid-connected photovoltaic (GCPV) system using power model. The power model used is presently applied in the testing, commissioning and acceptance test of grid-connected systems procedure in Malaysia. This study involved outdoor testing and validation of model through mathematical formula, root mean square error (RMSE), Pearson correlation coefficient (R2) and standard deviation (STD) determination. Results showed that most of the time, the actual power output was lower than the modelled power output. This implies that more derating factors should be considered in the existing power model such as aging and installation criteria.

Stand-Alone Photovoltaic Power System applications in Malaysia

This paper presents an overview and status Stand-Alone Photovoltaic Power System (SAPVPS) in Malaysia. Malaysia is located at equatorial line is suitable to generate a power supply from solar. Electrification of remote area in Malaysia shows progress in terms of capacity of SAPVPS installation. Malaysia seriously intends to invest in renewable energy has initiate many incentive and programs to ensures the future of solar in Malaysia is bright.

Performance analysis of 45.36 kWp grid-connected photovoltaic systems at Malaysia Green Technology Corporation

This paper presents the performance of a 45.36 kWp grid-connected photovoltaic (PV) system at Malaysia Green Technology Corporation (MGTC), Bangi, Malaysia. The site is located at latitude of approximately 2.96°N and longitude of 101.75°E. The system was commissioned on 14th June 2007 and the system performance has been monitored since 1st Feb 2008. The system comprises 45.36 kWp of PV array size, a 40 kW inverter and other balance of system (BOS) components. An irradiance sensor and two temperature sensors are connected externally to the system via the inverter to obtain the irradiance, ambient temperature and module temperature profiles at the site. In contrast, other performance data such as AC current AC voltage, DC current and DC voltage are recorded from the inverter. During the monitoring period, all data were recorded based on 15 minute interval. The system had produced 787.25 MWh of solar electricity since its being monitored with an average daily output of 144 kWh. On the other hand, the inverter efficiency has been fluctuating from 86% to 97%. The average monthly final yield was found to be 96 kWhkWp−1 while the performance ratio (PR) varies from 71.37% to 91.99%.

An Automated Solar Photovoltaic Biaxial Tracking System: SolT2A

This paper describes a prototype product code-named SolT2A. It is a system that automatically tracks the sun as it traverses the hemispherical sky vault. The system has been comprehensively used in photovoltaic (PV) satellite systems and is an option for terrestrial applications. For earthbound systems, locations near the Equator experience the crossing of solar altitude across the zenith daily and a reversal of the azimuth over a year. Consequently, static PV systems do not produce maximum generation. Thus SolT2A has been designed and built to address this problem. The system has a four-point solar irradiance sensors and compares their intensity levels. The differentials are analysed and processed by a controller before and then sent to a set of DC motors. Thus SolT2A is a self-correcting system that ensures maximum irradiance captured by the PV arrays at all times, thus ensuring maximum PV generation. Based on field data, the open circuit voltage produced by the SolT2A tracking system is up to 82% better than from static systems The over all increase in open circuit voltage production is between 15 to 20% daily. Further developmental work includes optimising power consumption of the tracking and cost benefit analysis.