Sankar Narayan Mahato

Robust voltage regulation of DC-DC PWM based buck-boost converter

This paper investigates the performance of DC-DC PWM based buck-boost converter with two degree-of-freedom (2 DOF) control to meet the loop robustness goals as well as to shape the output voltage response according to requirement. The design technique of this controller is simpler than that of the robust control techniques, such as H∞, control, μ-synthesis, applied in literature for converters. Moreover, 2 DOF control is already established in literature to provide robust compensation to boost converter. The performance of the buck boost converter is examined in the presence of (i) 60% perturbation in load current, (ii) 25% perturbation in input voltage and (iii) high frequency measurement noise. The 2 DOF control scheme has been shown to achieve the output regulation and obtain fast recovery in output voltage response, through simulation.

Mineral oil based high permittivity CaCu3Ti4O12 (CCTO) nanofluids for power transformer application

Power transformer is the heart of the power transmission and distribution in an electrical system and its lifeblood is transformers insulating oil that acts as an insulation of the transformer. The physical and electrical properties of insulating oil mainly depend on the constituents of insulating oil and the properties of oil can be optimized by introducing nanofluid. Mineral oil based CaCu3Ti4O12 (CCTO) nanofluids with various volume percent of CCTO (0 to 0.05 vol %) have been prepared under ultrasonication. These nanofluids (before ageing) were evaluated for the critical parameters such as AC breakdown voltage (BDV), loss tangent, dielectric permittivity, resistivity, acidity, interfacial tension, flash and fire point as per the procedure outlined in the ASTM and IEC standards. The nanofluids (NF-0 to NF-3) showed improvement in the AC breakdown voltage, tan delta, flash and fire properties. The AC breakdown voltage increased as the CCTO volume percent increase in the mineral oil. The nanofluids were also subjected to accelerated ageing and the critical parameters, evaluated on the aged nanofluids (ANF-0 to ANF-3), were compared with that of fresh nanofluids. The nanofluids do not show any significant change in the viscosity, however, influences on the electrical properties were observed. The improvement in electrical properties can be attributed to the formation of insulating boundaries in nanomaterial which acts as insulation barrier that hinders the breakdown mechanism.

Performance analysis of isolated 3-phase self excited induction generator using graph theory and PSO technique

This paper analyzes the steady state performance of isolated 3-phase self excited induction generator (SEIG) feeding balanced static resistive load. The effects of load and capacitance on magnetizing reactance, frequency, terminal voltage, currents have been shown in this paper. The model equations, which are nonlinear in nature, have been developed using graph theory. These equations can be easily solved by particle swarm optimization method. The performance of this algorithm has been compared with Newton-Raphson method. MATLAB has been used for simulation. The simulated results obtained using these algorithms help in understanding the steady state performance of SEIG.

A simple multi parameter measurement system using multi transducer

The present article portrays a design and implementation of microcontroller based system for different physical parameter measurement using multi transducer with very high accuracy. For maintaining accuracy of the system a novel method is used which is multi channel direct sequence spread spectrum technique and it is also used as a filter for eliminating low frequency noise to maintain accuracy. It also meets the demand of development of a microcontroller based embedded system for physical parameter measurement. The system should monitor and provides data for examining with high accuracy. The system is initially tested with two transducers but there is a provision to incorporate eight number of transducer with same accuracy.

Design of mathematical model and performance analysis of BLBLDC motor

In this paper an attempt has been taken to propose, the design of mathematical model of a Bearingless Brushless DC motor (BLBLDC). The performance of the motor using the mathematical model has been analyzed. The proper control of radial suspension force and the electromagnetic torque has been utilized for contact free rotation and spatial suspension of BLBLDC motor. The rotor does not have any mechanical bearing instead magnetic suspension force has been used. But this technique is different from conventional magnetic bearing. The rotor is enclosed with multi-winding stator which provides rotational force as well as spatial suspension force to the rotor. The comparative study validate the proposed mathematical model.

High accuracy mass measuring system using capacitive mass sensor

AbstactIn the area of mass production, the products are weighted using load cell based weighting system. A load cell may be capacitive or resistive, is an uncontrollable weighing device. Improvement in filtering increases the speed of weighing and enhances the measurement accuracy. In this paper a new algorithm and architecture is proposed as weight filter for the weighing system with capacitive load cell. We verify and implement the novel algorithm in the measuring products successfully.

High accuracy displacement measuring system using strain gauge based displacement sensor and direct sequence spread spectrum techniques in data acquisition system

The present article portrays a design and implementation of microcontroller based system for displacement measurement using strain gauge based displacement sensor. A displacement transducer may be capacitive or resistive, is an uncontrollable device. Improvement in filtering increases the speed of measurement and enhances the measurement accuracy. In this paper a new algorithm and architecture is proposed as filter for the displacement measuring system with strain gauge based displacement sensor. We verify and implement the novel algorithm with this displacement transducer in the measuring of displacement successfully.

A dynamic range differential capacitive sensor interface circuit with noise shaping model of sigma-delta modulator

Most of the resistive type capacitive sensor interface circuits are used for specific application but they limits to measure or detect small changes, thus capacitive sensors are widely used in industry. In this paper we present an interface circuit for capacitance-to-voltage conversion for dynamic range that not only offers good signal-to-noise ratio but also it is used for dynamic range. So many capacitive sensor interface circuit has been proposed but they suffers to increase accuracy, to minimize post processing errors as well as low power application. This circuit uses sigma-delta conversion technique to reduce the interferences and it also improves noise performance. The sigma-delta modulator directly converts capacitance to digital codes. In this brief, we present an interface circuit topology with dynamic range of capacitance-to-voltage conversion for differential capacitive sensors. Differential capacitive sensing circuit employed to cancel or reduce the parasitic or stray capacitance of the sensor probes. Besides the interfacing circuit the third order continuous-time sigma-delta modulator and its noise shaping model is also presented.

Artificial Bee Colony based design optimization of a six-phase induction motor

Artificial Bee Colony Algorithm (ABC) has been used to optimize the design of a six-phase induction motor (SPIM). Multi-objective function has been considered for optimization. Comparison of the optimum design using Artificial Bee Colony Algorithm with that of traditional design and Genetic Algorithm (GA) based optimum design has been presented, which shows that improved design can be achieved by Artificial Bee Colony technique of optimization. Comparison of the results obtained has been done to find the fittest method of optimization for the said purpose. Performances of the induction motor have been evaluated for each design effectively.

Two degree of freedom control of IM modeled through discrete lagrangian approch

In this paper speed control of induction motor (IM) with two degree of freedom (DOF) control strategy is addressed in discrete time domain. In order to do so, a novel discrete model of IM in synchronously rotating reference frame is developed with formation of discrete lagrangian. The two DOF controller is designed to meet robustness criteria in terms of gain margin, phase margin and sensitivity function through pole placement technique. The performance of the two DOF control for the discrete lagrangian model is examined for set point tracking and load disturbance rejection. The performance of two DOF control scheme is found to be satisfactory for the considered operating conditions.