Showing papers by "Nasrudin Abd Rahim published in 2003"

Lithium-ion battery charger for high energy application

Abstract: This paper describes the design of microcontroller-based battery charger to charge lithium-ion battery pack with the charging method, balancing technique, charging control algorithm, battery protection, battery management unit and implementation of the battery charger are discussed concisely. Advantages, disadvantages and problems arise are also discussed. In fact, an excellent battery charger offers very fast charge time, full capacity and balanced battery cells, low operating temperature and highly efficient and reliable.

FPGA-based ASIC design of the three-phase synchronous PWM flyback converter

Abstract: The design and development of a synchronous pulse-width modulation (PWM) generator suitable for the three-phase flyback converter is presented. The design is based on the Xilinx chip XC4005E field programmable gate array (FPGA). Two 30/spl deg/ of sine waveforms with two different carrier waveforms are used to generate the PWM. The PWM pattern proposed occupies less FPGA block cell, hence more space can be used for other control circuitry. The proposed technique enables the modulation index and the displacement factor to be changed externally. Results are provided to demonstrate the effectiveness of the design.

A dynamic input membership scheme for a fuzzy logic DC motor controller

Abstract: Conventional fuzzy logic controller uses input membership functions that consist of identical triangular input membership functions (MF) for all the subsets that are not located at the two ends of the universal set (center width constant or CWC). Some researchers in the field of motor controllers have started using narrower base triangular membership functions for the input subsets that are located at the center of the universal set and wider base triangles towards the two ends of the universal set (center width narrow or CWN). This new approach has proved to enhance the performance of the controller. This paper proposed a dynamic input membership function scheme which combines the center width narrow and the center width constant scheme together with a new scheme where the center triangular input membership functions has a wider width than those that are located more towards the two ends of the input universal set (center width wide or CWW). The dynamic input membership scheme (DIMS) applies CWN, CWC and CWW at different stages of the transient states of the controller step response to achieve a superior step response for a DC motor controller as compared to applications of only one type of input membership functions throughout the controller operation. Matlab simulation studies have been done to confirm the improved performance of the dynamic input membership functions as compared to the other schemes commonly employed.

FPGA based ASIC power-factor control for three-phase inverter

Abstract: In this paper, a new three-phase Inverter power-factor correction PFC scheme is proposed using Field Programmable Gate Array (FPGA) technology all the functions can be implemented in a single chip. The implementation tool fit the entered design into the target device (XC4008E). Design verification includes functional simulator, in circuit testing and timing simulation the main function is to verify the proper operation of the designed circuit. It will compile a design file into a configuration file that is optimized in terms of use of logic gates and interconnections for the target device. Power factor measures how effective electrical power is being used. A high power factor means that electrical power is being utilized effectively, while a low power factor indicates poor utilization of electrical power. The simplest way to improve power factor is to add power factor correction capacitors to your plant distribution system. In this paper a new technique is proposed to improve the power factor, experimental results are presented to show the effectiveness of the proposed technique.

Harmonic reduction in a three-phase rectifier with sinusoidal input current

Abstract: This article proposes a new approach to reduce harmonics generated by a three-phase diode rectifier. The proposed approach uses the input filters, six controllable switches, high-frequency isolation transformer, and the three-phase diode rectifier. The switching of the controllable switches is modulated by a novel pulse-width modulation (PWM) implemented in an XC4006 field programmable gate array (FPGA). This approach realizes sinusoidal input current waveforms with low electromagnetic interference and arbitrary output voltage. The output voltage can be controlled by variation of the modulation index in the range (0 < M < 0.98). The experimental results to compare performance between with and without the proposed approach are carried out to confirm its feasibility.

Modeling and simulation of the linear generator PWM multilevel inverter

Abstract: The paper describes the design of the multilevel converter, which acts as a link between the output of linear generator and the load. In linear generator the o/p frequency varies from 25 to 50 Hz depends on the load. Due to that, it is not suitable for many applications, which use 50 Hz AC. The actual linear generator output voltage waveform as simulated is similar in shape to the output voltage design results. The transformer-less multilevel converter is able to convert from the distorted non-50 Hz AC waveform to 50 Hz purely sinusoidal AC voltage and current waveforms at modulated output voltage. Pspice simulation results are presented to verify the validity of the model.