Single Phase Induction Motor Drive with Restrained Speed and Torque Ripples Using Neural Network Predictive Controller

In industrial drives, electric motors are extensively utilized to impart motion control and induction motors are the most familiar drive at present due to its extensive performance characteristic similar with that of DC drives. Precise control of drives is the main attribute in industries to optimize the performance and to increase its production rate. In motion control, the major considerations are the torque and speed ripples. Design of controllers has become increasingly complex to such systems for better management of energy and raw materials to attain optimal performance. Meager parameter appraisal results are unsuitable, leading to unstable operation. The rapid intensification of digital computer revolutionizes to practice precise control and allows implementation of advanced control strategy to extremely multifaceted systems. To solve complex control problems, model predictive control is an authoritative scheme, which exploits an explicit model of the process to be controlled. This paper presents a predictive control strategy by a neural network predictive controller based single phase induction motor drive to minimize the speed and torque ripples. The proposed method exhibits better performance than the conventional controller and validity of the proposed method is verified by the simulation results using MATLAB software.

A Novel Approach for Improving the PQ in SPIM

Single Phase Induction Motor(SPIM)is widely used in industries at starting stage to provide high starting torque.The objective of the work is to develop a drive for Single Phase Induction Motor that does not use a start or run capacitor.In this work,the researchers present the details about Maximum Power Point Tracking using series-compensated Buck Boost Converter,resonant Direct Current(DC)to Alternate Current(AC)inverter and matrix converter-based drive.The proposed method provides a variable starting torque feature that can be adjusted depending upon machine load to ensure Power Quality(PQ).The system uses Series Compensated Buck Boost Converter(SCBBC)to derive the power from solar source and a Partial Resonant Inverter(PRI)between the Matrix Converter(MC)and DC link battery to reduce the switching loss.The application of Space Vector Pulse Width Modulation(SVPWM)ensures the improvement of power quality at driving terminals of SPIM.The proposed system has been math-ematically modelled and simulated in MATLAB SIMULINK environment and was validated using standardized experimental verification.

A Method to Obtain Complex Transfer Functions of Four Order DC-DC Converters

Two TFs （transfer functions） are needed to analyze switching DC-DC converters in control-voltage mode： the duty-cycle to output-voltage （control to output） and the input-voltage to output-voltage （line to output）. To obtain these TFs a small-signal analysis is required. The CCM （continuous conduction mode） and the DCM （discontinuous conduction mode） analysis are different. When a circuit includes the loss resistances of the components, the number of parameters increases considerably, making manual nodal-loop circuit analysis techniques impractical to obtain the TFs. Moreover, these circuits are bilinear （non-linear） and it is necessary to linearize the equations at a DC operating-point （approximate linearization）. Vorp6rian describes a PWM （pulse-width-modulated） switch model that includes all non-linear parts of the DC-DC switching converters. This model can be linearized and replaced on the switching converter schematic leading to a linear circuit. At this point it is possible to use symbolic analysis programs to obtain these TFs or to simply apply numerical values for either the Bode diagrams or the calculation of poles and zeros. Here we describe an application of Ekrem Cangeici＇s method on X DC-DC converter to obtain control to output and line to output TFs in CCM and DCM including loss resistances. The method presented in this paper is optimized to use in the online publishing platform OctaveRS. Also the control to output TF for PCC （peak current controlled） in CCM is obtained.

In-phase thermal–mechanical fatigue investigation on hollow single crystal turbine blades

Thermal-mechanical fatigue（TMF）is the primary cause of failure of nickel-based single crystal turbine blades.TMF experiments have been performed on the critical section which is subjected to the most serious damage and determined by numerical calculation combined with service failure experience.An experimental system including the loading,heating,air cooling,water cooling,and control subsystems,is constructed to satisfy the TMF experimental requirements.This experimental system can simulate the stress feld,temperature feld,air cooling process,and TMF spectrum on the critical section under service conditions in a laboratory environment.A metal loading device and a new induction coil are developed to achieve the required stress and temperature distributions on the critical section,respectively.TMF experimental results have indicated that cracks initiated at the trailing edge of the suction surface on the critical section.Based on these experiments,life prediction and failure analysis of hollow single crystal turbine blades can be investigated.