Performance Analysis of Wimax with Different Modulation Techniques
Authors: P. Ashok Kumar, V. Sandeep Kumar
Abstract
In this paper, we show the advancements in broadband and mobile communication has given many privileges to the subscribers for instance high speed data connectivity, voice and video applications in economical rates with good quality of services. The bit error rate performance of WIMAX has been carried out for different modulation techniques like BPSK, QPSK, QAM 16, and QAM 64. The performance evaluation of various aspects of the simulated model is obtained by plotting graphs between Bit Error Rate and Signal to Noise Ratio for different modulation techniques. Orthogonal frequency division multiple access uses adaptive modulation technique on the physical layer of WiMAX and it uses the concept of cyclic prefix that adds additional bits at the transmitter end. The signal is transmitted through the channel and it is received at the receiver end. Then the receiver removes these additional bits in order to minimize the inter symbol interference, to improve the bit error rate and to reduce the power spectrum. In this paper, we investigated the physical layer performance on the basis of bit error rate, signal to noise ratio, power spectral density and error probability.
Perfomance Upgrading Of Engine By Oil Cooling System
Authors: Kiran Kenny, Shibu Augustine, Prasidh E Prakash,Arjun G Nair
Abstract
This deals with the process of, upgrading engine performance by oil cooling system for future vehicle applications result in the increase of high engine power, low fuel consumption. The wish to prevent the future situation where the engine oil could become very hot, formed the basis for this work. Engine oil, heat transferring rate and overall design of engine cooling systems were noted and studied. The most significant section was to make sure that the oil must not exceed the certain temperature limit. This gave answers to how the oil and engine components gets affected, if the oil exceeds the set temperature limit. To get an explict and measurable parameters, the goal of this paper was defined by estimating, the heat transfer demands will be in the future. An analysis was made to inspect how and if, the challenger use another kind of oil cooling. Concepts that showed to be interesting were analyzed more extremely with performance simulations and packaging studies. Concepts were analyzed and the performance simulations indicated that all the presented concepts can reach the heat transfer goals set earlier in this process. They however may use different methods, and meet the objective with different levels of efficiency. All the ideas which are noted with their heat transfer performance results and their advantages and disadvantages. The idea that showed to be the important in an oil cooling perspective, was to attach an extra heat exchanging device in series after the current plate heat exchanger. This is also a solution which will helps the current engine oil cooler by handling the extra heat produced during certain driving occasion. Best concept reached a heat transfer range of 40 kW at half of the air flow rate required by the second best concept. The concepts that has been presented will incriminate a change in the current oil cooling system design. The lack of accessible space in automobiles will also result in some rearranging of components in order to make space for an additional heat exchanger.
Peak Current Control Mode of a Symmetrical Half Bridge Push-Pull Converter Topology for Photovoltaic Array with P&O MPPT
Authors: Jasnah Hakkim, Liya Alias
Abstract
In this paper a peak current mode control(PCMC) of a symmetrical half bridge push pull converter for good dynamics and performance, capable of boosting up the voltage by controlling the power of a photovoltaic system using Maximum Power Point tracking (MPPT) control mechanism is proposed. The MPPT extracts the maximum possible power from the photovoltaic system and via the push pull converter it is fed to the load, which steps up the voltage to the required magnitude. The P&O MPPT algorithm proposed identifies the DC-DC converter’s suitable duty ratio which should be operated to obtain maximum power output and control converter’s dc-link voltage. PCMC bring the half-bridge capacitor voltage back to balance. The simulation is done using Matlab and the results are presented.
Over Current Recovery with Hysteresis for High Side Switches
Author: Sudharshana S.P
Abstract
Highside Power switches are vast used semiconductor devises in power management. Many Highside switches are not having inbuilt over current hysteresis protection. A technique is proposed in this document for over current protection with hysteresis and fixed time recovery. This can be implemented as a feedback circuit for Highside switches to protect from over current.
Optimization of PID Parameters using Genetic Algorithm for Hard Disk Drive Read/Write Head Control
Authors: Jaison John, C. Sathish Kumar
Abstract
Due to the increasing areal density of magnetic hard disk, it has become challenging to design a controller for hard disk drive servo. This paper demonstrates the effectiveness of GA based PID controller tuning for control of hard disk drive read/write head. In comparison with performance of PID controller tuned with conventional methods, the GA based method provides better time response specifications with normalized geometric selection, arithmetic cross over and uniform mutation.