Sreedhar Madichetty

Application of an Advanced Repetitive Controller to Mitigate Harmonics in MMC With APOD Scheme

In a modular multilevel converter (MMC), the second and other even-order harmonics in the circulating currents are mainly due to the fluctuations in the capacitor voltages in the sub modules of the MMC. The increased circulating currents affect the system performance and threatens the safety operation of power devices. To mitigate the circulating currents, this article puts forward the application of an advanced repetitive controller with alternate phase opposition and disposition pulse-width modulation technique. The proposed controller was operated in tandem with a proportional integral controller for better results of circulating current harmonic suppression and then the stability analysis was analyzed by the Popov criteria. This method is very simple to implement and suitable for multiple harmonic mitigation. Computer simulations and experimental results on a prototype shows that the proposed controller is effective and easy to implement for MMCs.

Voltage Balancing Scheme in MMC – A New Approach

Abstract This article proposes an online voltage balancing scheme using a new comparative reference wave modulation technique applied to modified modular multilevel converter (MMMC). Recent applications of modular multilevel converter (MMC) in high-voltage DC systems experience many problems with unbalancing of upper and lower arms, due to which circulating currents are rotating in the legs of MMC. These circulating currents pass through the arm inductors and create power loss across the inductor which consequently affects the efficiency of system. In order to overcome the unbalancing and to reduce the power losses, it proposes a new topology for existing MMC called as MMMC. Its main idea is to the balance the system voltage according to the difference between upper and lower arm currents. The upper and lower arm capacitors voltages can be well balanced by proposed technique. Compared to conventional PWM methods, this method can be realized easily. Particularly, this method has not used any kind of sorting technique, which makes it suitable for MMC with a large number of sub-modules. With experiments, the proposed method has been verified successfully.

A Review and Advance Technology in Multi-Area Automatic Generation Control by Using Minority Charge Carrier Inspired Algorithm

Abstract This article deals with automatic generation control of a multi-area interconnected thermal system in different modes using intelligent integral and proportional-integral controllers. Appropriate generation rate constraint has been considered for the thermal generation plants. The two cumulated thermal areas are considered with reheat turbines. Performances of reheat turbine on dynamic responses have been investigated. Further, selection of suitable integral and proportional-integral controllers has been investigated with a minority charge carrier inspired algorithm. Cumulative system performance is examined considering with different load perturbation in both cumulative thermal areas. Further, system is investigated with different area control errors, and results are explored.

An Efficient Wavelet based Automation Process for E-Admission in Universities of Odisha

E-admission or electronic admission is an electronic mechanism which convert the traditional office paper processes into electronic processes. In this type of admission, It creates a paperless system which is done in web based network. This is an Internet Communication Tool, which would improve the performance in admission in Universities of Odisha. E-admission can encompass both intra-office and inter-office communication for any Universities of Odisha. The main objective is to introduce total transparency and accountability leading to better E-Governance with in any Universities of Odisha. This type initiative is especially targeted at any Universities of India or world where public accountability is of special concern. Similar processes are being developed in many universities to aid compliance with the educational act. This paper introduces a noble solution for E-admission through an efficient automatic software technique. The solution is more customer centric rather than organization centric. It is also independent of any specific individual and hence confirms the ethics of transparency. The process of E-admission is implemented by a distributive cooperative algorithm & PSO based algorithm for fast searching. The data protection is achieved through wavelet techniques.

A survey on wind energy, load and price forecasting: (Forecasting methods)

The wind energy has an upward trend to continue over several decades, with the improvement of its turbine technology and reduction of energy production costs. Due to its unpredictable wind behavior and weather patterns, it may pose many problems including grid voltage balancing, synchronization, capital cost expenditure etc. So, there would be a definite need in forecasting the wind energy, its load and price. The use of these forecasting techniques may reduce the capital cost, installation and maintenance etc., Hence, in this article an attempt has been made to review the forecasting techniques for wind energy, load and price also tried to explore the best possible methods to forecast the behavior/pattern of the wind.