Bih Lii Chua

Optimization of partially shaded PV array using fuzzy MPPT

Solar photovoltaic (PV) array shows non-linear P-V characteristic when the array is illuminated under uniform solar irradiance. In this circumstance, the P-V characteristic consists only one maximum power point (MPP) along the functional operating voltage. However, the P-V characteristic has changed and become more complex with multiple MPP when the array is exposed under partially shaded conditions. This circumstance has caused maximum power point tracking (MPPT) algorithm faces difficulty to allocate the exact optimal operating voltage for PV array to generate maximum power. In this paper, initial voltage tracking function (IVTF) has been introduced to assign new initial voltage for tracking the absolute MPP when the PV array is at shaded conditions. Nevertheless, MPPT approach deals with the challenge of tracking the MPP in the faster mode while maintaining the power stability of the PV array toward the MPP. Therefore, fuzzy logic is embedded in the conventional MPPT to adapt the size of the perturbed voltage. The obtained results show that fuzzy logic based MPPT with IVTF is able to track the absolute MPP faster while minimizing power lost due to the power fluctuations.

Fuzzy Logic Based MPPT for PV Array under Partially Shaded Conditions

This paper presents the fuzzy logic based maximum power point tracking for the optimization of the solar photovoltaic (PV) array under partially shaded conditions. The PV system is modelled in MATLAB/SIMULINK where the PV array is formed by five PV modules connected in series. The PV characteristic of PV module and PV array under uniform solar irradiance are nonlinear but there are one maximum power point (MPP) can be identified. Nevertheless, the PV characteristic becomes more complex with multiple MPP when the PV array under partially shaded conditions (PSC). In this paper, maximum power point tracking (MPPT) approach based on perturb and observe algorithm has been investigated. Fuzzy logic is adopted into the conventional MPPT to enhance the overall performance of the PV system. The performances of MPPT and FMPPT are investigated particularly on the transient response and the steady state response when the PV array is exposed under different partially shaded conditions. The simulation results show that FMPPT has better performance where it can facilitate the PV array to reach the MPP faster and provide more stable output power.

Performance Analysis of Intelligent Transport Systems (ITS) with Adaptive Transmission Scheme

Various means of modern transports have already taken the initiative to incorporate computing and communication technology. This cross field area is coined as intelligent transportation systems (ITS). Transport systems of the future require fast and precise monitoring to ensure safety of such systems is guaranteed. Thus, the communication aspect demands seamless and minimal error whilst delivering vital data. However, the dynamic surroundings always post a challenge to wireless communications, taking account into a myriad of interference such as multipath fading, shadowing, dispersing and path loss. Furthermore, there is also case of mobility. In this paper, the performance of wireless communications with adaptive modulation and coding in vehicular scenarios were compared against rigid transmission techniques. Simulations were conducted over different mobility channel models against Signal-to-Noise ratio (SNR) to provide thorough analysis. Performance measure of Bit Error Rate (BER) and Packet Error Rate (PER) were used to provide understanding of the overall picture.

Particle Swarm Optimization Based Resource Allocation in Orthogonal Frequency-division Multiplexing

Current cellular wireless data communications require wide availability and satisfying quality of service to keep up with the rising number of wireless devices. It is challenging for the service provider to cater to different kinds of upcoming new services and applications as data rates vary apart in that respect. For that reason, it is of paramount importance to adaptively utilize the radio resources which are limited and valuable. The ability of Orthogonal Frequency-division Multiplexing Access (OFDMA) to split the entire bandwidth into smaller sub-carriers allows adaptive resource allocation to be performed in downlink communications. However, due to the time-varying nature of the wireless channel, not all links experience the same channel response. Therefore, this situation is akin to a strategic combination problem to find the best allocation out of the huge combinations according the current channel characteristics. This paper presents an evolutionary method, particle swarm optimization (PSO), to optimally allocate the rates and sub carriers to multiple users. The results display good convergences towards the optimal solution for a minimal transmit power allocation. At transmission intervals, the cellular base station will be able to use the best allocation relating to channel conditions of any point in time.

Development of a wireless device control based mobile robot navigation system

Tablets are highly functional and flexible platforms to pair with robotic autonomy and navigation control. The advantage of remotely controlling robots using mobile devices is location independence. New research is merging towards more applications for mobile devices and robotics. Specifically, more emphasis is given to the communication technology that connects mobile devices with robots. In this paper, the design and development of a mobile robot system with tablet is presented in detail. The wireless communications interfaced between the microcontroller, computer and tablet is described. The user is able to navigate the mobile robot to travel through points of interest via a GUI interface on the tablet.

Progressing toward urban topology and mobility trace for Vehicular Ad Hoc Network (VANET)

Mobile communication and intelligent transportation system (ITS) show a promising technology as it could enhance the traffic efficiency and promote on-road traffic safety. Vehicle Ad Hoc Network (VANET) is one of a notable example of successful wireless networking paradigm emerges from the combination of mobile communication and ITS. It allows wireless communication between vehicles and remote application. Many VANET related researches have been done in simulation rather than in real-world due to its inexpensive, repeatable and easily controlled experiment. Simulation of VANET can be divided into two types: network and mobility simulation. In order to develop a vehicular network service, a realistic mobility environment must be generated beforehand as it could greatly affect the performances of developed VANET protocol. In this paper, traffic simulator (SUMO) is used to generate realistic traffic of the city Kota Kinabalu, Sabah, Malaysia. Different scenarios are generated to evaluate the performance of VANET on such realistic developed topologies.

Maximum Power Point Tracking of Partially Shaded Photovoltaic Arrays Using Particle Swarm Optimization

This paper presents the particle swarm optimization based maximum power point tracking (MPPT) approach for maximizing output power of photovoltaic (PV) array under partially shaded conditions (PSC). During PSC, the P-V characteristic becomes more complex with multiple maximum power points (MPP). Most of the conventional MPPT approaches will be trapped at the local MPP and hence limiting the maximum power generation. As such, the investigation on particle swarm optimization (PSO) based MPPT is carried out to maximize the PV generated power principally under PSC operation. The performances of conventional MPPT approach and the proposed PSO-MPPT are investigated particularly on the transient and steady state responses under various shaded conditions. The simulation results show that the PSO-MPPT is able to facilitate the PV array to reach the global MPP as well as to assist the PV array to produce more stable output power compared to the conventional perturb and observe (P&O) algorithm.

Characterization Study of Using Acoustic Signals for Underwater Non-Destructive Testing

Non-destructive testing in structural inspection is a list of techniques that is used to evaluate the condition of a structure in order to determine whether cracks, flaws defects or damages occur in structural build without causing any damage to the test object. This work presents the characterization study of using acoustic signals for underwater non-destructive testing. The optimum operating frequency for sensors, transmission angle between the transmitter and receiver and operating distance between the sensors with reflecting medium are determined. Early results can be implied in exploring the possibility of using acoustic signals in underwater structural inspection with non-destructive testing methods.