A New Evolutionary Technique Big Bang Big Crunch Optimization

So that the voltage and current is of poor qualities and the switching frequency causes more amount of switching losses. Those drawbacks are rectified using three phase neutral point clamped multilevel inverter. The voltage and current quality are better and the switching losses are reduced when compared to the conventional technique. Also the THD is found to be better.

Pulse width modulation or PWM is the basic analysis for control modulation in the power electronics. PWM is a powerful and commonly used technique for controlling the analog circuits or power to electrical devices and made practical by a processor’s digital output such as the modern electronic power switches. Theoretically, the zero rise time and fall time of an ideal PWM, waveform represents a way of driving latest semiconductor power devices. Except for the resonant converters, majority of power electronics circuits are controlled by PWM signals of several forms.

Introduction: An inverter is a DC to AC converter, used to convert a dc input voltage into a symmetrical ac output voltage of desired magnitude and frequency. The waveshape of output ac voltage of inverter should be sinusoidal. However, practical inverters give output voltage that are non-sinusoidal and contain harmonics. The waveshapes of output voltage are square, quasi-square or distorted sinusoidal. Inverters used in low and medium power applications normally give square or quasi-square wave output. However, in high-power applications sinusoidal waveform is required, so inverters are carefully designed to give sinusoidal output with low distortion.

The impact of the proposed sequences has been simulated for 0.4 modulation index with a 0.5 lagging power factor load (power factor angle 60°). The simulation setup consists of the following software: 1) MATLAB/Simulink – used to implement the modulation strategies and switching sequences, and 2) PSIM – used to simulate the T-NPC inverter running with an R-L load and to provide conduction and switching losses of each switch. The inverter switching pulses were generated within Simulink and were fed to PSIM through sim-coupler module which provides a link between PSIM and simulink for the purpose of co-simulation [29].

Many of these conventional DC–DC converters have the disadvantages of operating at high duty-cycle, high switch voltage stress and high diode peak current. The conventional boost high step-up converter can provide very high voltage gain without operating at high duty-cycle by employing a coupled inductor, a switched capacitor and an additional diode. Non-isolated high step up converter overcomes this drawback. This converter reduces voltage stress on switch and diode by using additional one capacitor and rearranging components in conventional single switch high step-up converter. At the same time, the switch voltage stress is reduced greatly, which is helpful to reduce the conduction losses by using low power rated components and efficiency will increase. Single switch is used in the non-isolated high step up converter, thus reduce the entire cost of the converter. This non-isolated high step-up converter is used in many applications such as renewable energy system using low voltage energy sources such as fuel cells, solar panels,

For the traditional voltage source PWM inverter, we have the well-known relationship: . Equation (10) shows that the output voltage can be stepped up and down by choosing an appropriate buck–boost factor BB,

relationships.This new seven-level inverter is configured using a capacitor selection circuit and a full-bridge power converter, connected in cascade. The capacitor selection circuit converts the two output voltage sources of dc–dc power converter into a three-level dc voltage, and the full-bridge power converter further converts this three-level dc voltage into a seven-level ac voltage. In this way, the proposed solar power generation system generates a sinusoidal output current that is in phase with the utility voltage and is fed into the utility. The salient features of the proposed seven-level inverter are that only six power electronic switches are used, and only one power electronic switch is switched at high frequency at any time. A prototype is developed and tested to verify the performance of this proposed solar power generation system.

Modelling of the series transformer, VSC and LC filter is presented in this section. A time-varying threephase

The comparison of above three algorithms for 8, 16 and 32 bit operands with corresponding voltage and frequency are tabulated in table I

It is observed that the power factor is maintained closer to unity when the input voltage is reduced from 230V to 110Vrms. Figure 11 (a) and (b) shows the power factor correction of controller for various load condition such as 20% (60W) and 75% (230W). The power factor for the system is found to be 0.84 for light load condition and 0.99 for full load condition. The THD of input current at full load with predominant third and fifth harmonic components are shown in Figure 12(a) and (b).Third harmonics is found to be 4.8% and fifth harmonic component is 4.9% which are well within IEC 61000-3-2 standard during wide range of load variations. The variation in power factor with load is shown graphically in Figure 13(a). It can be inferred from the graph that improved resettable control operates at high power factor for all load condition whereas the conventional PI control has poor power factor under light load conditions. Figure 13(b) shows the comparison between the efficiency of the converter for varying load conditions with the conventional control method and the resettable integrator control. The converter’s efficiency is maintained at 92% for light load conditions and 96% for fully loaded condition with integrator control technique. Thus the improved resettable integrator controller provides a very simple and reliable solution for power factor correction and

Satellite power system is one of the key components which ensure the functioning of all its systems. 25 Constantly evolving satellite power blocks and the main areas of improvement are solar cell 26 efficiency, the use of more energy- efficient chemical batteries and more efficient control methods [1-27 5]. Advanced methods of management of power plants subsatellite, allowing always to provide 28 matched mode of associated with the use of digital technology, including technology management of 29 provisions of the operating point of devices using pulse width modulation (PWM)[6-7]. One of 30 directions of development of space technology is the use of complexes of multiple spacecraft, "main 31 satellite"-"subsatellite". Also one of the modern

Fig. 5.10. Control of the dc–dc converter to produce less power under voltage sag: (a) grid voltages, grid currents, actual duty cycle, input voltage of the dc–dc converter, estimated duty cycle; and (b) dc-link voltage.

The flexible AC transmission system (FACTS) concepts, based on applying state-of-the-art power electronic technology to existing AC transmission system, improve stability to achieve power transmission close to its thermal limit [4]. Such devices are installed by utilities and by many private entities in India. In order to achieve this identical goal other way is by converting existing 400kV / 765 kV double circuit HVAC line to HVDC line without any modifications in the existing tower structure, insulators and conductors considering heavy pollution as the worst case.

The innovative inverter technology produces safe, smooth power, protecting your sensitive electronics (computers, smartphones, etc.) from damage.

This thesis is submitted as partial fulfilment of the requirement for the award of the Bachelor of Electrical Engineering (Electronics)