DEEPAK KUMAR NAYAK, S. RAMA REDDY: Atmel Microcontroller Based Soft Switched PWM ZVS Full Bridge DC to DC Converter (pp. 5-11)

Abstract: This paper deals with the simulation and implementation of soft switched PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using a DC to DC converter. This converter has advantages like reduced switching losses, stresses and EMI. Input DC is converted into high frequency AC and it is stepped down to 12V level. Later it is rectified using a full wave rectifier. Laboratory model of microcontroller based DC to DC converter is fabricated and tested. The experimental results are compared with the simulation results.

Keywords: DC-DC converter, full bridge converter, soft–switching, zero voltage switching (ZVS).

 

N. ROMAN, M. G. ALEXIU, S. CARAMAN, M. BARBU, I. BIVOL, E. CEANGA: Adaptive Filter Used as a Dynamic Compensator in Automatic Gauge Control of Strip Rolling Processes (pp. 12-19)

Abstract: The paper deals with a control structure of the strip thickness in a rolling mill of quarto type (AGC – Automatic Gauge Control). It performs two functions: the compensation of errors induced by unideal dynamics of the tracking systems lead by AGC system and the control adaptation to the change of dynamic properties of the tracking systems. The compensation of dynamical errors is achieved through inverse models of the tracking system, implemented as adaptive filters.

Keywords: Automatic gauge control, adaptive control, inverse model, adaptive filtering, optimization.

 

MARIAN GAICEANU, MADALIN COSTIN: DC Link Current Estimation in Wind-Double Feed Induction Generator Power Conditioning System (pp.20-26)

Abstract: In this paper the implementation of the DC link current estimator in power conditioning system of the variable speed wind turbine is shown. The wind turbine is connected to double feed induction generator (DFIG). The variable electrical energy parameters delivered by DFIG are fitted with the electrical grid parameters through back-to-back power converter. The bidirectional AC-AC power converter covers a wide speed range from subsynchronous to supersynchronous speeds. The modern control of back-to-back power converter involves power balance concept, therefore its load power should be known in any instant. By using the power balance control, the DC link voltage variation at the load changes can be reduced. In this paper the load power is estimated from the dc link, indirectly, through a second order DC link current estimator. The load current estimator is based on the DC link voltage and on the dc link input current of the rotor side converter. This method presents certain advantages instead of using measured method, which requires a low pass filter: no time delay, the feed-forward current component has no ripple, no additional hardware, and more fast control response. Through the numerical simulation the performances of the proposed DC link output current estimator scheme are demonstrated.

Keywords: DC link current estimator, PWM, back-to-back power converter, power balance, DFIG.

 

SILVIU EPURE, EMIL ROSU: Indirect Control of a low power Single-Phase Active Power Filter (pp. 27-34)

Abstract: This paper deals with a low power, single phase active filter used to compensate nonlinear loads. The filter uses the indirect control method and it is based on a particular connection between filter, polluting load and grid to avoid time-consuming mathematic operations or signal processing computations and assures good rejection of harmonic currents injected by the nonlinear load into the grid. A scale model was first simulated in Simulink and then physically implemented. The paper presents simulation and experimental results, and highlight problems encountered during experiments.

Keywords: active power filtering, indirect control, PWM rectifier, THD.

 

CIPRIAN BĂLĂNUŢĂ, GELU GURGUIATU, TOADER MUNTEANU, GRIGORE FETECĂU, MIHAI OANCĂ: Improving the Power Factor at Unbalanced Consumers (pp. 35-39)

Abstract: Unbalanced consumers have led to power quality problems. It is therefore necessary to have on hand solutions and equipment capable of improving the power quality. This paper provides a comparison on improving the power factor at unbalanced consumers by using two methods the installation of a capacitor in the PCC (point of common coupling) – analysis made through analytical method; and installation of a shunt active power filter in the PCC – analysis made through simulation using Matlab/Simulink software.

Keywords: power quality, power factor, active power filter, unbalance.

 

CODREŞ BOGDAN, GHEORGHE PUŞCAŞU, GABRIEL MURARIU, ZANOSCHI AURELIAN: Identification of a Nonlinear Pneumatic Servo System Using Modular Neural Networks (pp.40-47)

Abstract: Sometimes, in the case of highly nonlinear systems the traditional approaches of identification and control could be difficult to implement. In this case, a good alternative are the neural networks. In this paper a modular neural network for the identification of a pneumatic servo system is proposed. This approach is based on the partitioning of static characteristic of the pneumatic system. The neural modules are implemented with multilayer neural networks.

Keywords: modular neural networks, nonlinear system, identification, characteristic partitioning, pneumatic servo system.

 

U. SOWMMIYA, V. JAMUNA: Voltage Control Scheme for Three Phase SVM Inverter Fed Induction Motor Drive Systems (pp. 48-53)

Abstract: This paper presents an efficient implementation scheme for the closed-loop voltage control of an induction motor incorporating ‘Space Vector Pulse Width Modulation (SVPWM)’. Voltage control is required to meet the variation in the input voltage and to regulate the output of the inverter. Space Vector Modulation (SVM) is an algorithm for the control of Pulse Width Modulation (PWM). Comparative study has been made between SVM and PWM techniques. From the simulation results, SVM has reduced THD compared to pulse width modulation techniques. Thus, SVM gives better harmonic response and higher efficiency.

Keywords: Closed loop voltage control of Induction Motor, Pulse Width Modulation, Space Vector Modulation, Three Phase Inverter.

 

S. ARUMUGAM, S. RAMA REDDY: A Novel Analysis of Class E Inverter Based Induction Heating System (pp. 54-60)

Abstract: This paper deals with the simulation and implementation of class E inverter based induction heater system. Class E inverter is analyzed; simulated and implemented. Utility frequency AC Power is converted into high frequency AC power using class E inverter. This high frequency AC is used for induction heating. Open and closed loop systems are modeled and they are simulated using Matlab Simulink.The results of simulation and implementations are presented. The laboratory model is implemented and the experimental results are obtained. These Experimental results are correlated with the simulation results.

Keywords: AC Chopper, Total Harmonic Distortion, Pulse Width Modulation, Induction motor.

 

S. ARUMUGAM, S. RAMA REDDY: Simulation Results of Single Stage AC- AC Converter for Induction Heating (pp.61-67)

Abstract: This paper presents simulation of single stage Induction heating system with series Load Resonance. Low frequency AC is converted in to High Frequency Ac using newly developed ZVS-PWM high frequency inverter. This High Frequency is used for Induction Heating .Single stage AC-AC converter system is modeled and simulated using Matlab simulink. The simulation results of ZVS-PWM high frequency system are presented. The effectiveness of this UFAC-to-HFAC direct power frequency converter using IGBTs for consumer high-frequency IH appliances is evaluated and proved on the basis of simulation results.

Keywords: Induction Heating (IH), Pulse Width Modulation (PWM), Zero Voltage Source (ZVS), High frequency Inverter, Simulink.

 

P. PARVATHY, N. DEVARAJAN: Computer Simulation of Phase Shifted Series Resonant DC to DC Converter (pp.68-72)

Abstract: This paper deals with digital simulation of phase shifted series resonant DC to DC converter using Matlab Simulink. The Simulink models for open loop and closed loop systems are developed and they are used for simulation studies. This converter is capable of producing ripple free DC output. Switching losses and switching stresses are reduced by using soft switching. This converter has advantages like high power density and low switching losses. Theoretical predictions are well supported by the simulation results.

Keywords: Phase-shifted series resonant converter, quasi current mode control, soft switching.

 

MARIAN GAICEANU, ELENA VONCILA, RAZVAN BUHOSU: Optimal Control for Electric Vehicle Stabilization (pp. 73-81)

Abstract: The main objective of the paper is to stabilize an electric vehicle in optimal manner to a step lane change maneuver. To define the mathematical model of the vehicle, the rigid body moving on a plane is taken into account. An optimal controller delivers the adequate angles in order to stabilize the vehicle’s trajectory in an optimal way. Two degree of freedom linear bicycle model is adopted as vehicle model, consisting of lateral and yaw motion equations. The proposed control maintains the lateral stability by taking the feedback information from the vehicle transducers. In this way only the lateral vehicle’s dynamics are enough to considerate. Based on the obtained linear mathematical model the quadratic optimal control is designed in order to maintain the lateral stability of the electric vehicle. The numerical simulation results demonstrate the feasibility of the proposed solution.

Keywords: electric vehicle, optimal control, stabilization, Riccati.

 

ROMULUS MILITARU, LIVIU ADRIAN CĂLIN, GEORGE-CRISTIAN CĂLUGĂRU, ADRIAN-LOREL GEORGESCU: A New Numerical Calculus Solver – Numerical Engineering Software (pp. 82-92)

Abstract: The project presented in this paper, entitled Numerical Engineering Software is an integrated solution which contains a various range of numerical methods for the solving of diverse calculations and mathematical approximations from science and engineering. The environment consists at the current stage of development of five chapters: Matrix Algebra, Polynomial Approximations, Roots of Equations, Numerical Integration and Cauchy Problems. The program works through dedicated application windows characteristic to each operation that can be performed and it has the advantage of an accuracy of the results, imposing by the use.

Keywords: linear systems, eigenvalues and eigenvectors, approximations, numerical cuadrature and cubature, Cauchy problems, mathematical software.

 

G. SUNDAR, S. RAMA REDDY: Multilevel Inverter Based Statcom for Power Quality Enhancememt in Multi Bus System (pp.93-97)

Abstract: This paper deals with simulation of STATCOM in multi bus system for power quality enhancement. The unique structure of the multi level voltage source inverter (VSI) permits it to attain high voltages with low harmonic content. The STATCOM injects reactive power in to the proposed 14 bus system. The simulation of the STATCOM is performed in the MATLAB/Simulink environment and the results are presented. The computational and analytical results are tabulated for comparison.

Keywords: STATCOM, Power quality, voltage source inverter.

 

SABINA COSTACHE: An ADCSP-Based Non-Monotonic Framework for Medical Diagnosis (pp.98-109)

Abstract: The ability to reason within a dynamical environment is of crucial importance in Artificial Intelligence. The present paper models nonmonotonic reasoning by means of a DCSP (Dynamic Constraint Satisfaction Problems) framework, taking advantage of the representation facilities of direct argumentation systems. The algorithm presented below applies dynamic backtracking for the approximate computation of the admissible semantics, which was used to define the concept of multiple diagnosis. The final application of our work is a system for medical diagnosis, that models its search space efficiently and dynamically, while confronted with sequential tests. It asserts and rejects beliefs in different component elements of the diagnosed domain following a nonmonotonic schema which is very close to a human expert’s reasoning model.

Keywords: clinical decision making, hybrid intelligent systems, direct argumentation systems, nonmonotonic reasoning.

 

V.V. SUBRAHMANYA KUMAR BHAJANA, S. RAMA REDDY: A Novel ZCS-ZVS Hybrid Bidirectional DC-DC Converter for Fuel Cell and Supercapacitor Application (pp. 110-114)

Abstract: This paper proposes a novel ZCS-ZVS hybrid bidirectional DC-DC converter based on fuel cells and supercapacitor devices. The described converter employs only one high frequency transformers to couple the half-bridge and full-bridge circuits together in the primary side and voltage doubler circuit in secondary side. Boost type converter can limit the output ripple current of the fuel cells; hybrid full-bridge structure can change operating modes according to the different input voltage. All the primary side switches can turn on under zero-current-switching condition (ZCS) in boost mode and transformer secondary side switches can turn on under zero-voltage-switching(ZVS). The operating principles of the converter are described in details. The proposed converter provides output voltages of the range 300-400V. With the proposed ZCS-ZVS concept, the MATLAB simulation results of the application of fuel cell and supercapacitor have been obtained and compared to those of hybrid bidirectional dc-dc converter (ZVS based) and the applications in order to show the superior performance of the proposed concept.

Keywords: DC-DC, ZVS, ZCS, ZCS-ZVS, Fuel cell, Supercapacitor.

 

V. SIVACHIDAMBARANATHAN, S.S. DASH: Analysis and Experimental Verification of Series Resonant PFC DC to DC Converter (pp. 115-121)

Abstract: The aim of this work is to simulate and implement Series Resonant PFC DC – DC converter using Matlab Simulink. The quality of power consumption in terms of power factor and electromagnetic interference (EMI) levels are becoming one of the most important aspects in the design of static power converters. The series resonant PFC converter has many advantages such as high power density, reduced electromagnetic interference (EMI), reduced switching losses and stress. A DC – DC series resonant PFC converter has been developed. Both simulation studies and hardware implementation are done. The simulation results agrees well with the hardware results.

Keywords: DC to DC Series Resonant Converter, High frequency Inverter.

 

M. NARENDRA KUMAR, K.S.R. ANJANEYULU: Simulation of Four Switch PWM AC Chopper Fed Single Phase Induction Motor (pp. 122-127)

Abstract: To improve the performance of motor drives, there is a need to improve the quality and reliability of the drive system. With the high power handling capability of IGBT, pulse width modulated AC chopper can be used in high power applications. AC chopper using pulse width modulation provides substantial advantages over conventional line commutated AC controllers. To alleviate the problems associated with the conventional AC voltage controllers, pulse width modulated AC chopper fed induction motor drive is developed and presented in this paper with an appropriate control circuit. FFT analysis for voltage and current is performed for the developed system. The harmonics are reduced by using LC filter at the output. It is proved that total harmonic distortion obtained from the developed circuit is less than that of phase controlled AC chopper system. Simulation results closely agree with the analytical predictions.

Keywords: AC Chopper, Total Harmonic Distortion, Pulse Width Modulation, Induction motor.