Roselina Arelhi

LQG stable stabilizing control: some recent results

The synthesis of controllers using LQG, H/sub 2/ and H/sub /spl infin// techniques is well established. The modifications needed to turn these advanced controllers into implementable devices is now of considerable interest. As a result, the topics of reliable control, integrity, order reduction and stable controllers have received new impetus. In this paper the stable controller algorithm of Halevi, Bernstein and Haddad (1991) is investigated. Results for numerical implementation are presented. A new variation of their basic technique is developed, and some optimal root loci aspects described. Some numerical results close the paper.

Modelling of ultracapacitor using a fractional–order equivalent circuit

Research shows many dynamic systems such as ultracapacitors are better characterised using fractional–order system. This paper models ultracapacitor through electrochemical impedance spectroscopy (EIS) measurement. Ultracapacitor response to this measurement is used to determine the parameters of its equivalent circuit. Constant phase elements (CPEs) are incorporated in the equivalent circuit model to better describe ultracapacitor dynamic behaviour. The ultracapacitor impedance response is modelled by zones and the circuit elements are connected in congruence with its response at the respective zone. The proposed modelling approach permits obtaining a model that has parameters that are associated with ultracapacitor physical process. Consequently, this approach leads to a fractional–order model. Simulation of a fractional–order model in MATLAB/SIMULINK is given in detail and the model performance is compared with experimental data. Results reveal that the voltage evolution during current turn–off is better described. The voltage decay at this period is influenced by the CPE exponent, n.

The performance of a solar PV system using supercapacitor and varying loads

This paper analyses the application of supercapacitors in a standalone off-grid solar PV system. The solar PV system at University of Nottingham Malaysia Campus (UNMC) was tested using a programmable load. The programmable load was used to apply various load values to the system. The results on the effect of using different loads will be analysed and tested with and without a supercapacitor bank. Results show that the supercapacitor can supply peak current demand and preserve battery state of charge during the day. This system can be implemented in rural areas or small industries.

Measurement failure robustness in H2/H∞ reliable controller synthesis

Attention has returned towards the design of closed loop control systems which remain stable under measurement (or actuator) failure. Engineers wish to introduce reliability into the closed loop system by including redundant measurements. These systems are designed to be robust to measurement failures in terms of retaining closed loop stability and desirable system performance. Two methods of denoting measurement failure within a system are introduced. The existing design procedures for designing reliable H∞ controllers are considered before re-formulating the reliability issue in the H2 framework. The system performance for different measurement failure structures can be measured in terms of the bound on the H∞ norm or the H2 cost.

Study on the effect of supercapacitors in solar PV system for rural application in Malaysia

This paper presents the investigation on the effect of supercapacitor in a standalone off-grid solar photovoltaic (PV) system. The supercapacitor is introduced in this paper to extend battery lifetime and reduce maintenance cost. The supercapacitor is integrated with the battery and tested by using a programmable load in a solar PV system located at University of Nottingham Malaysia Campus (UNMC). The programmable load was used to apply various load values to the system to simulate real usage in a rural household. The results are tested and analyzed for a battery system with and without supercapacitors integrated. The results are extremely promising and show that the addition of supercapacitors significantly improves a battery based solar PV system.

Solar Hybrid PV System for Off-Grid Electrification in Semenyih, Malaysia

A low maintenance solar photovoltaic (PV) system is designed to supply power to households in rural areas that are not connected to grid utility. A 2kWh system was developed in a custom made rural cabin in Semenyih, Malaysia. The system was tested with varying loads by using a programmable load. The programmable load is used as a real time load to test the power usage and efficiency of the system. The results obtained shows that the proposed system can supply sufficient power to rural homes at low maintenance costs. The results obtained from this system can be used for implementation on rural homes without the need for backup power generators such as diesel generators.

Kalman Filter as a pre-processing technique to improve the support vector machine

The Support Vector Machine is widely used as a classification tool to analyze data and recognize patterns. In certain applications of Support Vector Machine, noisy data can greatly affect accuracy and performance. To improve the accuracy of the system, the Kalman Filter has been proposed as a suitable pre-processing technique which can be implemented before using the Support Vector Machine to classify the information. This system has been tested using a dataset obtained from a pipeline defect monitoring system in the departments pipeline laboratory. This test rig uses long range ultrasonic testing to detect minor defects inside a stainless steel pipe. MATLAB simulations show promising results where Kalman Filter and Support Vector Machine combination in a single system produced higher accuracy compared to the discrete wavelet transform in a noisy environment.

A MATLAB Simulink implementation of speech masking based on the MPEG psychoacoustic model 1

The MPEG standard for digital compression for high-fidelity audio provides two implementations of the psychoacoustic model, psychoacoustic model 1 and psychoacoustic model 2. The ISO/1EC 13818-3:1994(E) document contains descriptions of these models. This model is of interest for the development of speech enhancement algorithms that concentrate their effect on the perceptible components in a speech signal. MATLAB/Simulink software has been used to construct a system for implementing speech masking. It consists of two main parts; the estimation of masking threshold, and the application of masking including reconstructing the speech. The system has been successfully tested with pure tone and speech signals, and undergone some quality assessment testing using human subjects. The system will be used as a tool for investigating cross-channel interactions for binaural speech enhancement.