K. Y. Ahmed

Design and Analysis of a Digital Controller for Boost Converter with Renewable Energy Sources for Domestic DC Load

Renewable energy sources like solar PV produces DC voltage which is converted to AC before connecting to domestic grid network. The conversion process from DC to AC and back to DC at load end introduce additional losses in the system. With increasing availability of modern DC loads and growing use of renewable energy, the use of DC network for domestic load supply is on increase in order to reduce energy conversion losses. Presented in this paper is a fast transient digital controller for DC-DC boost converter with energy source from solar PV for domestic DC loads like lightings. The boost converter was model as both steady and dynamic state. Digital controllers were designed using both digital redesign approach and direct digital redesign approach. The system demonstrated fast transient response that is essential for tightly regulated output voltage from constantly varying renewable energy generations.

Modeling and Simulation of Power Electronic Distribution Transformer Based on a Three Level Converter

In this paper, a new type of power electronic distribution transformer (PET) has been introduced based on the power electronics converter on the primary and secondary sides of the transformer. This PET has three stages and the input stage has a three-level, three-phase rectifier. The middle stage has two three-level single-phase converters and a high-frequency transformer; and, the output stage is a three-phase, two-level inverter. This power electronic distribution transformer provides many advantages, such as power factor improvement, reactive power compensation, eliminating harmonics, and controlling and protecting itself (PET) with minimum size, compared to the traditional transformer. The MATLAB/Simulink was used to analyze and validate the power electronic distribution transformer.

Two-diode model for parameters extraction of photovoltaic module under temperature variation

This paper study the effect of redistributing the series resistance in the two-diode model of the PV module according to its physical components, considering the relation of each component to temperature variation. The proposed model divide the series resistance into two materials: metal and semiconductor, constructing the mathematical model for the overall model. The model is found to improve the accuracy in calculating the maximum power point with temperature variation, which contribute to the job of PV power converter designers and circuit simulator developers.

Theoretical analysis of the series parasitic resistance in photovoltaic cell

An accurate estimation of the series resistance in the PV model is crucial to the prediction of the maximal output power of the PV module, especially under temperature variation. This Paper proposes a theoretical expression to calculate accurately the value of this resistance. The proposed expression comes from the physical nature of the various elements constructing this resistance, plus the reverse relation of the output power with cell temperature, utilizing manufacturer datasheet only. The proposed expression was tested against experimental measurements and previous work, showing a clear improvement in tracing the series resistance values under varying temperature.

Modeling of Steady State and Transient State of the Power Electronic Distribution Transformer

This research study presents a new type of power electronic distribution transformer (PEDT), aimed to overcome the disadvantages of the traditional electromagnetic distribution transformers. This new proposed model is named as power electronic distribution transformer incorporating power electronic converters in both primary and secondary sides, in addition to the high-frequency transformer. Moreover, the PEDT is capable of providing many advantages, such as power factor improvement, voltage sag/swell, reactive power compensation, harmonics elimination, self-protection and size reduction as compared to the conventional electromagnetic transformer. MATLAB/Simulink is used to simulate the proposed model. The simulation results show that the model is capable of offering an additional DC bus on the primary side as well as high power conversation ratios and power quality improvement.

Development of Observer State Output Feedback for Phase-Shifted Full Bridge DC–DC Converter Control

Controllers are designed to regulate output voltage and improve dynamic performance of dc–dc converter to variable supply voltage, load current or circuit element variation. Conventional controller like PID has narrow dynamics that limit its application to quiescent supply input voltage and load current change. Recent research efforts are exploiting state of the art power electronics devices and high computational speed digital signal processor to improve transient and dynamics performance of power converters through advanced modern control techniques. This paper presents a design and evaluation of observer state output feedback controller for phase-shifted full bridge zero voltage switching dc–dc converter output voltage regulation to widen the supply input voltage. The converter closed-loop control was implemented in MATLAB/Simulink environment and the results demonstrated improved transient response to wider supply voltage and sudden load current change as compared with the conventional PID controller.

Design and simulation of phase-shifted full bridge converter for hybrid energy systems

This paper presents design and Simulink implementation of zero voltage switching (ZVS) phase-shifted full bridge dc-dc converter. The phase-shifted full bridge PWM dc-dc converter is widely used in high power, high voltage applications due to the advantages of high power handling capability with low switching and conduction losses. The phase shift feature of the control signal allows ZVS thereby eliminating the switching losses during FET device transition. It also minimize the parasitic effect and conduction losses at high frequency operation thereby increase system efficiency. A 3kW, 100 kHz high frequency phase-shifted full bridge converter was design and simulated in Matlab/Simulink to analyze the system performance prior to experimental implantation. The converter is intended for hybrid energy systems (HES) application in which a state space controller will be developed with wider dynamics to accommodate variable input sources mostly from renewable energy resources like solar and wind power. The converter simulation results shows that the system achieved greater than 90% efficiency at full load current.

Comparison of fuzzy logic control and PI control for a three-level rectifier based on voltage oriented control

This paper presents a voltage oriented control (VOC) for a three level, three-phase PWM rectifier using a fuzzy logic control strategy. The PI control was replaced by fuzzy control aimed to reduce the total harmonic distortion (THD) on the grid side, to improve the power factor (PF) as well as keep the output DC voltage to the required level when a dynamic disturbance happens. The MATLAB/Simulink and fuzzy logic toolboxes have been used to investigate the steady-state and transient-state behaviors for the proposed controller. As the result shows, it was verified that the fuzzy logic controller is much better than the traditional PI controller, and the fuzzy logic controller provides a stellar performance in the transient state.