A New Evolutionary Technique Big Bang Big Crunch Optimization

condition is given in Fig. 8, it can be seen that the output voltage takes nearly one cycle to settle whereas

Fig. 12 shows the switching loss reduction using the DPWM2O, DPWMLPF2 and GDPWMO sequences in comparison to the conventional SVPWM strategy for 30°-60° power factor angle range. It can be seen that the DPWM2O and DPWMLPF2 sequences provide maximum switching loss reduction only at 30° and 60°, respectively. In other power factors, their loss reduction capability reduces. On the other hand, the GDPWMO strategy reduces switching losses around 50% over the entire range of power factor angle, similar to the analytical results shown in Fig.

As flight systems advances, new power generation is necessary which should be able to provide high-quality power generation, and solution might be Variable Frequency electrical system. The Variable frequency is generated with the power of the perfect sine wave and no harmonic distortion. This type of “Variable Frequency is generated from a generator with a 3-stage brushless with the variable speed and generates the frequency from 360 – 800Hz with an output voltage of 200V.” (Fadil. R.A., Eid. A., & Salam. M. A.,2013)

Switching power converters offer an easy way to regulate both the frequency and magnitude of the voltage and current applied to a motor shown in fig(1). As a result much higher efficiency and performance can be achieved by these motor drives with less generated noises[3].

Now a days, the switching power supply market is flourishing quickly. The trend is for DC-AC converters with low cost, higher efficiency, power saving that enable maximum features. In this project, a single-stage three-switch buck-boost inverter is designed, where stepping up, stepping down and inversion operation will takes place in single stage. This proposed inverter will overcome all the drawbacks of traditional one. Coupled inductor plays a very important role in energy transfer and eliminates the use of line frequency transformer. As the inverter having only three switches, the controlling of switches also easier than conventional one. And it has also advantages like compact design, reduced switching losses, component size, and cost.

The objective of the proposed internship can be divided into the following sub-objectives – 1) develop a control strategy with variable operating switching frequency to dynamically control current ripple and reduce system losses, and 2) develop a current control strategy to improve dynamic response for the two level inverter fed PMSM drive; while taking into account the effect of different operating regions and drive design parameters. More specifically the following tasks will be accomplished for each sub-objective:

This is to certify that the seminar report entitled “Hyperloop” submitted by Mr. Rushi Patel (14BEE093) & Mr. Romil Patel (14BEE092), students of B.Tech, 4th Semester towards the partial fulfillment of the requirements for the award of the degree in Bachelor of Technology (B.Tech) in Electrical Engineering of Nirma University is the record of work carried out by him/her under my supervision and guidance. The work submitted has in our opinion reached a level required for being accepted for examination.

Abstract— Conventional three-level discontinuous pulse-width modulation (DPWM) techniques are typically employed in variable frequency drive applications to reduce inverter switching losses and provide maximum benefit for load power factor angles in the range from 30° lagging to 30° leading. This paper proposes a series of DPWM templates for lower power factors and a generalized DPWM strategy for three-level T-NPC inverters operating with modulation indices lower than 0.5. With a change in the power factor, the proposed strategy adapts the inverter pulse sequence by combining different portions of the proposed DPWM templates within one fundamental cycle and ensures minimum switching instances during transitions. Consequently, the strategy perfectly aligns the no-switching durations of the inverter pulse-patterns with the respective load-current peaks, achieving a 50% switching loss reduction for all operating power factor angles (90° lagging to 90° leading) at modulation indices lower than 0.5. The paper provides an analytical evaluation of the proposed strategy on the three-level T-NPC inverter switching losses. The simulation and experimental results demonstrate the effectiveness of the proposed three-level generalized

Brushless DC (BLDC) motors are used for many low and medium power drives applications due to their high efficiency, high flux density per unit volume, low maintenance requirement, low EMI problems, high ruggedness and a range of speed control. The commutation in PMBLDCM is accomplished by solid state switches of a three phase voltage source inverter (VSI). There is a necessity of an improved power quality (PQ) as per the

The LCL filter achieves the objective of smoothing of output current from the VSI. In an interconnected system, the implementation of the filter results in cost savings, reduction in overall weight and size of the components. Good performance can be achieved in the range of power levels up to hundreds of kW, with the use of small values of inductors and capacitors. The higher harmonic attenuation of the LCL filter allows the usage of lower switching frequencies to meet harmonic constraints

Pulse width modulation technique based cascaded multilevel inverters have been receiving increasing research attention in the past few years. These power converters provide advantages of high power quality waveforms, low switching losses, and high-voltage capability. It has led to many applications such as high-power motor drive, variable speed drive, Uninterruptible Power Supply and active power line conditioners. The various topological structures of the multilevel inverter suggestions

Fig.3.11 Schematic diagram of switching logic for single-phase three-level SPWM converter (u is the input signal for the corresponding block, not the global signal)

The variable switching technique is a part of the conventional DTC technique . It was firstly introduced by Takahashi and Noguchi around 1980’s this method is the wide band of the switching frequency of the inverter even when the flux and torque references are kept constant. The conventional DTC scheme has some inherent

Abstract— This paper presents unipolar pulse width modulation technique with sinusoidal sampling and Space vector pulse width modulation are analyzed for three-phase Diode clamped multi-level inverter from the point of view of the Phase voltages, currents, voltage across the split capacitors and Total harmonic distortion. The necessary calculations for generation of PWM for the two modulation strategies have presented in detail. It is observed that the unipolar modulation ensures excellent, close to optimized pulse distribution results but THD is high compared to SVPWM. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.

The advantage of the method is that it is very simple. But it has two disadvantages. The first method cannot completely eliminate the low order harmonics. Therefore the low order harmonics cause loss and high filter requirements. The second method is the high switching frequency which causes high switching loss and low efficiency