This paper focuses on the design, modelling and simulation of voltage multiplier circuits for step-up AC-DC linear power supplies. The voltage multiplier is commonly used in applications that require the conversion of an AC low voltage to a very high DC voltage. Those applications require very low currents, thus, the capacitor selection is not an issue. However, when the voltage multiplier is part of a power supply, the load current becomes larger, which makes the capacitors selection more difficult. To help designers in the capacitors selection some design formulas are presented. Simultaneously, a simple simulation technique that is able to predict the circuit behaviour will be presented, revealing also essential for the design process.

There are several methods for modelling the network availability and one of the most widely used is the enumeration of elementary paths which is based on the principle of mutually exclusive events. In this paper we apply a new method, called - the method of algebraic formulation. This method is based on the operation with algebraic objects (polynomials) and their corresponding transformations. By using this method is developed a model of self-healing WDM ring, which uses wavelength channel protection and calculates the availability of different sized rings. It is also made the calculation of the availability of ring components, links and nodes. Therefore, it is shown how number and length of the links and also the redundancy within the node affect the availability between two nodes within the ring.

In this paper we want to describe proposal of the fuzzy control of synchronous motor with permanent magnet and impact of deployment of membership functions of fuzzy controller on a regulation quality of a synchronous permanent magnet motor (PMSM). In the first part of this paper is described mathematical model of synchronous motor with permanent magnets and designed controller by using fuzzy logic. Fuzzy controller for a synchronous motor has been designed and compared for 3, 5 and 7 membership functions. Design and simulation of fuzzy control were done in Matlab/Simulink.

Tension control plays an important role in assuring product quality and process stability in steel rolling industry. Especially on looper control, there are a lot of applications where latest control theories had been applied, however, looperless interstand tension control of roughing mill remains a challenging problem. This paper proposes a looperless fuzzy interstand tension control system for a roughing mill of wire rod mill in Slovakia Steel Mills, a.s. Strážske. Review of looperless tension control techniques and the brief description of rolling process are also presented. Roughing mill simulation model with proposed control system was used to perform rolling simulation and results were compared with experimental results from the roughing mill with conventional control structure. The result from the test demonstrated reliability of the proposal.

This paper presents simple generalized scalar PWM algorithms for three and five-level inverter fed vector controlled drive. The proposed PWM technique uses the notion of imaginary switching times and hence does not require sector and reference voltage vector calculations. Based on the magnitude tests, the minimum and maximum times will be calculated. From which the generalized offset time expression is derived. By varying a constant between 0 and 1 in offset expressions, various PWM methods such as continuous and discontinuous PWM techniques are derived. Thus, the all PWM techniques brought under one umbrella. Moreover, the same generalized PWM approach can be easily extended to multilevel inverters by increasing the number of carrier signals. To evaluate the performance of proposed PWM technique, numerical simulation studies have been carried out on multilevel inverter fed vector controlled drive in MATLAB environment. From the results, it is observed that when compared with continuous modulating PWM technique discontinuous modulating signal based PWM techniques give reduced switching losses for same switching frequency. Moreover, the quality of waveforms is increased as the number of level increases.

Induction motors are widely used in most of the Industries. Induction motors draw very high current in the order of 5 to 8 times the rated current during starting. Starting of a higher rating Induction motor using Autotransformer has been found great importance in limiting the starting current and improving the starting torque compared to star-delta starter. This paper discusses the design and analysis of an energy efficient Autotransformer starter of rating 6.6 kV, 110 kVA to start an induction motor of rating 6.6 kV, 250 KW. The Autotransformer was designed with on-load tap changing facility of eight tapping’s ranging from 50 % to 85% with each step tapping of 5%. Laser Scribed 23ZDMH85 material and conductor of current density 3.07A/mm2 are proposed in the present work to reduce the total losses. The feasibility of achieving a reduction of about 22% in total losses compared to conventional transformer is discussed in detail. At 50% tapping, unity power factor the estimated efficiency of the autotransformer is 99.21%.

This paper presents a novel technique to solve the problem of unit commitment through sorting of units into different clusters. This sorting is implemented in order to decrease the overall operating cost and to assure the various constraints that involve minimum up/down. Unit commitment problem is an important optimization task in daily operational planning of power systems which can be mathematically formulated as a large scale nonlinear mixed-integer minimization problem. A new methodology employing the concept of cluster algorithm called as additive and divisive hierarchical clustering has been employed in order to carry out the technique of unit commitment. Proposed methodology involves two individual algorithms. While the load is increasing, additive cluster algorithm has been employed while divisive cluster algorithm is used when the load is decreasing. The proposed technique is tested on a system with generating units in range of 10-100 and the performance of the proposed technique has been reported through simulation results.

Modern inverters have been employed to achieve high dynamic operation in the context of variable speed drives. But due to high dv/dt introduces Zero Sequence Voltage (ZSV) results in adverse effects like bearing currents and electromagnetic interference. In this proposed work, the techniques to overcome the drawbacks due to conventional inverter and multilevel inverter have been presented i.e, by using multilevel inverter fed open end winding. In this paper the performance characteristics of Induction motor with different PWM techniques like sinusoidal PWM (SPWM), third harmonic injection PWM(THIPWM) have been analyzed and the harmonic analysis has been carried out using MATLAB/SIMULINK environment and to validate the proposed work, several simulation results for different modulation index are listed out.