K. Deepa

Design, analysis and control of a new multi-output flyback CF-ZVS-QRC

A new multi-output flyback constant frequency zero voltage switching quasi resonant converter with low switching and conduction losses for aerospace applications is presented in this paper. The proposed converter is designed for outputs of 5 V/1 A and 12 V/0.5 A with resonant frequency of 165 kHz. A simple control method based on a single chip two pulse resonant controller UC3861 is developed to regulate 5 V output of the proposed converter and the other output voltage is maintained constant at 12 V. A prototype model of this converter is developed and the control method is implemented. The cross correlation effects of the two outputs are studied for different load variations and supply disturbances in experimental set-up. Results reveal the superiority of the proposed method.

Implementation and comparison of a new MOC with post regulators

A comparative study of two different types of post regulators is carried out in this paper. First one is low drop out post regulator (LDO) and second one is DC-DC step down LTM 4601 HV post regulator. These post regulators regulate the auxiliary high power output of the multi-output flyback dc-dc converter, designed for providing supply for the telemetry tracking transmitter subsystem of the satellite. The requirements for space applications are taken into consideration while designing.

Hybrid renewable energy system: Optimum design, control and maximum utilization with SIBB converter using DSP controller

Global warming and the shortage of fossil fuels increase the usage of renewable energy resources to satisfy the future energy demand of our depleting planet. This paper presents an innovative Switching logic for hybrid Distributed Energy Generators (DEG) by using a Single Input Buck-Boost (SIBB) converter and DSP controller based on their availability. With this proposed logic maximum amount of energy is extracted from the renewable energy resources depend on their availability. The combination of suggested switching logic and circuit configuration allows the two renewable energy resources, to supply the load individually or simultaneously based on the availability. The fast operation and reliability of DSP controller is utilized to increase the efficiency of the proposed system at the most. At any given instant to achieve extreme system efficiency three different modes of operations are projected. To analyze the real time feasibility of this logic the system is simulated by using MATLAB/Simulink 2010a; and the obtained results are studied and presented in the past. In laboratory a hardware model of the system is developed along with integrating the switching logic proposed for the learning of system in contradiction of the real world conditions. The results attained are discussed and presented in this paper.

Harmonic analysis of a modified cascaded multilevel inverter

In Multilevel Inverters, Cascaded H bridge converters are considered to be the most preferred form of converters. But in these converters as the number of staircase levels in output voltage increases the dc source requirement also increases, thereby limiting its application. This paper tries to address the above mentioned problem by developing a Modified version of Cascaded Multilevel Converters which require reduced number of dc voltage source for increased levels in output voltage as compared to conventional cascaded converters. The spectral quality analysis of output voltage obtained for different loads is also shown signifying the merits of modified converters. Due to these advantages the drawback in the implementation of conventional cascaded converters in electric vehicles or in industrial applications is overcome by modified cascaded inverters. In this paper, the developed Modified Cascaded Converters are simulated in MATLAB/ SIMULINK and the THD of different output voltage levels are compared for different loads.

Fuzzy based bidirectional converter

The core topic of the paper discuses bidirectional buck/boost converter implemented using soft switching. In addition to a soft switched DC-DC conversion, the circuit also facilitates an additional output which makes the system capable of supporting multiple applications. The circuit under discussion uses fuzzy logic for the closed loop operation which has better overall performance compared to other conventional converters. The circuit has been simulated in Mat lab Simulink software and analysis of both the closed loop and open loop operations are discussed below.

Fuzzy based flyback converter

DC-DC converters can be viewed as dc transformers that deliver a DC-DC voltage or current at a different level than the input source. The unregulated DC voltage is converted into regulated DC voltage at required level under varying load and input voltage condition. The control of output voltage is performed in a closed loop using the principle of negative feedback.The fuzzy logic controller for DC-DC converters i.e. Fly-Back Converter offers an alternative way to implement a central action that exploits the inherent variable structure nature of converter. The controller acts fast to changes in the converter output voltage producing good load regulation. This control technique offers converter stability for robustness, good dynamic response and implementation is simple. Hence, this paper is the result of an attempt to design aDC-DC Fly-Back Converter and an FLC for the same. The paper also draws a comparison between a conventional PI and fuzzy controllers for the aforementioned converter.

Solar powered ultrasonic cleaner

A Dual output half bridge converter combined with a resonant parallel fed inverter for ultrasonic cleaner is presented in this paper. The output of the inverter is 230V sinusoidal voltage with high frequency (28kHz) for ultrasonic cleaner applications. To obtain better load regulation PI controller is incorporated with the system for regulating 20% of load change. The simulation is carried out for a 58W power application. Solar power is used as input for the converter and output of the converter acted as the input for the inverter. The switching stress and losses are reduced due the resonant adopted for the inverter and thereby the increase in efficiency is also analyzed.

Fuzzy based flexible converter for satellite electronics

Single module DC-DC converter apt for two applications of same power and different output voltages is proposed with its relevant simulation results to substantiate the converter working. The suggested multi output flexible converter provides a provision to select one among the four available output combinations. The selection of required output combination is done merely with the help of output connectors, without changing any circuit parameters. A simulation model of the converter with one of the four combinations is done in MATLAB Simulink. Turn on at zero voltage for active devices, and turn off at zero current for passive devices are accomplished because of the associated LLC resonance principle. A fuzzy controller is also introduced for zero voltage regulation of the converter for change in load current.

Two-port DC-DC converter with flyback inverter for rural lighting applications

A two port DC-DC converter, combined with a modified flyback inverter, is presented in this paper. The output of the inverter is 230V sinusoidal voltage at 50Hz used for supplying rural lighting applications. Combination (solar and battery) of the energy sources along with a voltage doubler forms the two input port of the DC-DC converter for solar-battery hybrid systems. To obtain a low frequency output voltage for the load modified flyback inverter structure is utilized. A control algorithm implemented to supply the load using PV and battery sources either independently or simultaneously for maintaining the constant output voltage is also presented. This work focuses on simulation studies of the same to verify the converter working using PSIM software.

Soft switched flyback converter for SMPS applications

Isolated converters find wide application in SMPS, telecommunication, rectifiers etc. Among these topologies flyback converter is best opted for SMPS applications due to its simplicity in design, operation and less component count. High frequency dc-dc converters are subjected to high switching losses hence an auxiliary switch is designed to perform soft switching in main switch. The devices used in the converter are operated either in ZVS or ZCS to reduce the switching loss of the converter. This improves the converter performance. The converter designed is simulated, realized and presented in detailed for a laboratory model of 1.08W, 3.3V, 50 kHz.