Oladimeji Ibrahim

Matlab/Simulink model of solar PV array with perturb and observe MPPT for maximising PV array efficiency

The efficiency of commercially available solar PV module is very low in the range of 10-25 % In order to maximise their operating efficiency and to reduce installation cost, maximum power point trackers (MPPT) are coupled with the system. The output power of solar PV depends on solar irradiance level, incident angle, temperature and load current which all contribute to non-linear varying I-V characteristic during operation. MPPT ensures that a PV cell, module or panel is operated and maintained at the reference voltage that correspond to maximum power point for particular operating solar irradiance and cell temperature. A 220 W solar PV panel is modelled in Matlab-Simulink to study solar PV characteristics under different solar irradiance and working cell temperature. A Perturb & Observation MPPT technique incorporated for maximising the output power of the PV panel shows that the percentage deviation from the ideal PV power is about 10 % for different operating solar irradiance and cell temperature.

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.

Single phase inverter with wide-input voltage range for solar photovoltaic application

Solar energy is considered as fastest growing renewable energy source after wind energy for electricity generation. Solar energy is a free, clean abundant sun energy considered as inexhaustible source for electricity generation. Solar photovoltaic system is characterised with variable output power due to its operation dependency on solar irradiance and cell temperature. To maximize the energy generation potential of solar PV, research effort is focused on solar cell manufacturing technology to increase its generation efficiency and exploring advancement in power electronic devices for small and large scale deployment. Presented in this paper is a single phase inverter with no transformer for solar PV application. A closed loop DC-DC boost converter that accepts wide input DC voltage from 40 V - 60 V to produce constant 330 V DC voltage is modelled in Matlab/Simulink. An H-bridge 2-level inverter was used to convert the DC voltage to chopped AC voltage which was then filtered to give pure sinusoidal AC of 230 V RMS. The output voltage of the inverter has a very low total harmonic distortion of less than 1 % which makes the system suitable for local AC load and grid connection.

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.

Comparative studies of PID controller tuning methods on a DC-DC boost converter

This paper presents comparative studies of PID controller tuning methods on a DC-DC converter. A DC-DC boost converter was modelled using averaged state space method for controller design and dynamic analysis. PID controllers were designed using three different PID tuning methods; namely the Ziegler-Nichols frequency domain method, damped oscillation method and Good Gain method. The Matlab/Simulink was used to model and analyse the system transient response in terms of rise time, settling time, percentage overshoot and steady state error to step change input for their suitability in power supply design application. Among the three methods, the damped oscillation method demonstrated moderate fast rise and settling time with the advantage of lower overshoot to set point change.

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.