Hou Pin Yoong

Maximum Power Point Tracking for PV Array Under Partially Shaded Conditions

Solar photovoltaic (PV) array which is exposed to the uniform solar irradiance shows the non-linear P-V characteristic. Nevertheless, the P-V characteristic becomes more complex with multiple maximum power point (MPP) when the array is operated under partially shaded condition. Conventional maximum power point tracking (MPPT) approach which is designed to track the MPP will be trapped at the local MPP. Therefore, one of the challenges is to continuously track the absolute MPP while the environmental factors such as solar irradiation, PV temperature and partial shaded condition are rapidly changing. This paper presents a novel method of parallel tracking function to assist the on-line fuzzy logic perturb and observe (P&O) MPPT to continuously search beyond the trapped MPP operating voltage point. The information of PV array such as the operating voltage and the corresponding generation current are stored in the database. The characteristics of the shaded array can be estimated via simulation and the absolute MPP is identified via the tracking function. The simulation results show that the enhanced fuzzy logic P&O MPPT is capable of tracking the real absolute MPP during the partially shaded condition.

Fuzzy Logic Based MPPT for Photovoltaic Modules Influenced by Solar Irradiation and Cell Temperature

This paper presents fuzzy based perturb and observe maximum power point tracking in solar panel. The solar system is modelled and analysed in MATLAB/SIMULINK. The photovoltaic panel has an optimal operating voltage where the PV panel can produce maximum power at this particular point. Due to the nonlinearity of the voltage-current characteristic in solar panel, it is difficult to determine analytically the maximum power operating voltage that varies with the change of solar irradiance and cell temperature. Maximum power point tracking (MPPT) is implemented to identify the maximum power operating point, subsequently regulate the solar panel to operate at that particular operating voltage for maximum power gaining. Perturb and observe (P&O) MPPT and fuzzy based optimized P&O MPPT are developed and the performances of both controllers are examined at variable solar irradiances at different temperatures. Simulation results show that fuzzy based P&O MPPT has better performance where it can facilitate the solar panel to produce a more stable power.

Design and development of a tablet based real time wireless data logger

To date, data loggers are getting more implementation in business and home applications compare with several years ago. Data loggers can be customized according to the application requirement based on the available resources in the market. Thus, this creates a cost effective solution for the end user. In this paper, a wireless data logger with remote control capability via PC and tablet is introduced. The proposed wireless data logger is developed using microcontroller with analog-to-digital converter (ADC). The design of the portable wireless data logger is compact and light to increase the mobility and usability. Sampled data with time stamp from real time clock (RTC) module will be stored into SD memory card which is attached to controller board. Wireless data logger can directly transmit the data to end user if the device is in the communication coverage or stored the data into memory card if it is out of range. Graphic user interface (GUI) developed using Visual Basic and Android application. These applications can communicate with wireless data logger through wireless XBee module and Bluetooth module. End user can change the data logger settings such as, data sampling frequency, date and time remotely.

Modeling of Acoustic Channel for Underwater Wireless Communication System in AUV Application

This paper present the modeling of seawater acoustic channel to yield the optimum carry frequency for autonomous underwater vehicle (AUV) wireless communication system. Many underwater acoustic wireless communications had been explore whereby the exploration is mainly done for a specific distance. However, the wireless communication distance of an AUV with its control vessel varies due to the task at certain depth. This current AUV is design with an operation depth of 0 to 2000m. Therefore, the existing model had limitation when the operation depth varies base on the task assignment. This is because the optimum frequency to noise ration varies with respect to the distance of the transmission. To surmount the existing modeling method, this paper presents an improved method to identify the optimum carry frequency for AUV wireless communication system. Mathematical model with the relation of frequency, distance and noise is formulated and simulation is carried out to tabulate the optimum frequencies at various distances. From the frequency band, the average frequency is identified as the optimum transmission carries frequency. The identified frequency will be used for further hardware development.

Node collaboration for distributed beamforming in wireless sensor networks

Collaborative beamforming (CB) is introduced in wireless sensor networks (WSNs) to improve the transmission power and the energy efficiency of the networks. Using a subset number of nodes from a network of sensors, they collectively transmit a common message with different proper weights to an intended location. Different geometrical location of the subset of nodes will produce different transmission gains. Due to erratic deployment of the sensor nodes in the networks, the assignment for the sensor nodes in wireless sensor networks is vital to achieve better array pattern synthesis. In this paper, a node selection method based on uniform circular array is presented. Simulation and performance analysis are carried out to demonstrate the beam pattern performance of uniform circular in performing collaborative beamforming.

Performance analysis of utilizing coding nodes in wireless networks

Network Coding is a method that effectively combines several packets from different sources and broadcasts the combined packet to several destinations in single transmission time slot. Each destination is capable to extract the intended information by decoding from a common packet. In short, network coding is a method that improves the throughput for wireless networks and wired networks. However, while it increases the throughput of networks, it also causes side effects such as complexity of packets management and increased delay for coding opportunity. In this paper, genetic algorithm is proposed to optimize the resources for network coding. Genetic algorithm will search for suitable routes to the destination according to the desired throughput with a desired multicast rate. The simulation results show that the average end to end delay of network after minimizing coding nodes is less than normal network coding.