The resonant converter (RC) is finding wide applications in many space and radar power supplies. Among various RCs LCL, LCC, and LCL-T topologies are broadly used. This manuscript presents a comparative evaluation of steady-state stability of LCL, LCC, and LCL-T resonant configurations. Careful analysis favors LCL RC among the aforementioned three configurations since the stability region is good for the LCL RC over the other configurations. Also, this paper presents a comparative evaluation of proportional integral (PI) controller and fuzzy logic controller for a modified LCL RC. The aforementioned controllers are simulated using MATLAB and their performance is analyzed. The outcome of the analysis shows the superiority of fuzzy control over the conventional PI control method. The LCL RC is proposed for applications in many space and radar power supplies. Design, simulation, and experimental results for a 133-W, 50-kHz LCL RC are presented in this manuscript which provide high efficiency (greater than 89%) even for 50% of load. Efficiencies greater than 80% are obtained at significantly reduced loads (11%). In this paper, the applicability of the Philips advanced RISC machine processor LPC 2148 is also investigated for implementing the controller for an RC.

Stability and performance investigation of fuzzy controlled LCL resonant converter in RTOS environment

\n\nInverters are finding applications in electrical field where conversion\nfrom Direct Current (DC) to Alternate Current (AC) has become an inevitable option. The need of\nMulti Level Inverter (MLI) is to provide a high output power from medium voltage source. High\npower quality is the very basic important requirement for MLI used in medical electronic equipment.\nHarmonic elimination in MLI is a challenging one and is solved by optimum switching of\npower electronic switches present in the MLI topology.\n\n\n\nSeveral control strategies have been proposed for harmonic elimination in multilevel\ninverters. Newton-Raphson method is the conventional and iterative based method to obtain optimum\nswitching angle to minimize the Total Harmonic Distortion (THD). But it requires an initial\nguess of switching angles which is very close to the exact solution. To overcome this, harmonic\nelimination is converted into an optimization task and is solved by using evolutionary algorithms\nsuch as Genetic Algorithms (GA) and Particle Swarm Optimization (PSO). GA and PSO offer optimum\nswitching angles to minimize THD and used to increase the robustness of the system.\n\n\n\n The performance of proposed symmetric 21 level multilevel inverter with GA and PSO\ntechniques are analysed and the objective of minimum THD is obtained by using MATLABSIMULINK\nsoftware.In experimental setup, FPGA controller has been used to generate the Pulse\nWidth Modulation (PWM) control signals according to the proposed soft computing based switching\nstrategy. The experimental result is used to verify the ability of the proposed system for the\ngeneration of desired output voltage with minimum THD.\n\n\n\nThe proposed symmetric MLI with evolutionary algorithm based switching is a good\nchoice for medical electronic equipment used in hospital to obtain quality power with minimum\nTHD.\n

Application of Evolutionary Algorithms for Harmonic Profile Optimization in Symmetric Multilevel Inverter used in Medical Electronic Equipments

A conventional front-end rectifier causes line current distortion and reduces the power factor, which result in lowering power quality for Light Emitting Diode (LED) drive system. Hence, this paper projects the design, simulation and comparison of novel PI tuned by the fuzzy logic controller with the conventional PI controller for modified SEPIC rectifier to produce the required load voltage along with supply-side unity power factor and less distorted supply current with limited harmonic content for LED lighting in healthcare applications. A prototype of 100W, 48V LED driver was developed for testing the performance of the controller.This paper presents the modified SEPIC LED driver with PI integrated fuzzy and classical PI for controlling voltage. For controlling source current, classical PI is chosen. Both are equipped with the modified SEPIC rectifier. Both conventional PI control and novel fuzzy tuned performances were compared.The proposed control topology operated modified SEPIC rectifier was analyzed and the corresponding power factor and THD were measured. The operational evaluation of the proposed LED driver using fuzzy tuned-PI/PI controller combinations for different output power is provided in Table 2. Sustained regulated DC voltage of 48V was achieved even when the load resistance varied within a specific range. Power factor of 0.9995, which is close to unity, was also achieved. The relative analysis was made with conventional PI and trendy PI integrated FLC controller which is provided in Table 3. The usage of PI integrated fuzzy logic controller minimized the peak overshoot to be around 1.3% and rise time of 0.5s which are lower when compared to the conventional PI controller. With reference to Fig. (8a), the source current THD of the conventional PI controller was observed to be around 7.39%. Having PI integrated FLC, THD was further reduced and for rated load, it was found to be 1.39%. The power factor of the conventional PI controller is around 0.9974. PI integrated fuzzy logic controller improved the power factor to 0.9995 with fuzzy tuned PI controller in action as shown in Fig. (8b). A prototype of 100W, 48V LED driver was developed for testing the performance of the controller. A power quality analyser was employed for measuring power factor and THD, shown in Fig. (10a). 3.633% of harmonic distortions at the source current and 0.9980% of input power factor was achieved for rated load power. 4.510% of supply current THD with 0.9931% input power factor was achieved for low load power.This manuscript suggests a modified single switch SEPIC LED driver for 48V output operated healthcare equipment. Simulation study of this driver shows the better performance. In order to analyze the performance, a comparative study was conducted by using the classical PI and the novel PI integrated fuzzy controller. Satisfactory results regarding enhanced quality of power, regulated load voltage, quick rise time and settling time were achieved. The source current THD has been reduced to around 1.39% which is less than 5% as per the IEEE-516 prescribed standard and the power factor has been improved to 0.9995 by implementing the fuzzy tuned PI controller. The above results favor the suggested modified SEPIC LED driver for practical healthcare applications.

Design and Implementation of High Power LED Lighting System for Health Care Applications

This project work aims in exploring a quadratic boost converter which has low voltage ripple achieved using extreme duty cycles and PWM strategy. Normal quadratic boost converter topologies require a higher amount of stored energy by available in the capacitors used. The energy stored capability is directly proportional to the size of the capacitors. By using the minimum stored energy method, the converter size reduces. Also this transformer less proposed topology is suitable for renewable energy applications.

Design of Quadratic Boost Converter for Renewable Applications

It is necessary to control the aspects such as injected current to the three-phase grid, power factor and dc-link voltage to extract maximum power from the photovoltaic (PV) system so as to improve the results of a three-phasegrid-tied PV system. A Robust Input Output Partial Feedback Linearization Control (RIOPFLC) approach is proposed to control these factors to stabilize the three-phasegrid-tied system. This paper proposes an approach that robust in control and ensures the occurrences of uncertainties will not affect the PV system model. These uncertainties are examined based on the provided matching conditions using MATLAB/SIMULINK at different contingency and changes in atmospheric conditions. From simulation results, it is observed that the RIOPFLC provide better performance in the above parameters at different operating conditions.

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Improved Robust Controller Design for Stabilization of Grid-Tied Photovoltaic System

1,3,4,6 Department of Electrical and Electronics Engineering, Syed Ammal Engineering College,Ramanathapuram-623502, Tamilnadu, India 2 Department of Electrical and Electronics Engineering, Mepco Schlenk Engineering College, Sivakasi-625005, Tamilnadu, India 5 Department of Electrical and Electronics Engineering, KLN Information Technology, Madurai, Tamilnadu, India 7 Department of Electronics and Communication Engineering, Syed Ammal Engineering College, Ramanathapuram-623502, Tamilnadu, India

P. Karuppa Samy

Papers

Performance Investigation of SHE PWM Implementation of GA Based LCL Resonant Inverter in Marine Applications