A Single-Input Single-Output Approach by using Minor-Loop Voltage Feedback Compensation with Modified SPWM Technique for Three-Phase AC–DC Buck Converter

The modified sinusoidal pulse-width modulation (SPWM) is one of the PWM techniques used in three-phase AC–DC buck converters. The modified SPWM works without the current sensor (the converter is current sensorless), improves production of sinusoidal AC current, enables obtainment of near-unity power factor, and controls output voltage through modulation gain (ranging from 0 to 1). The main problem of the modified SPWM is the huge starting current and voltage (during transient) that results from a large step change from the reference voltage. When the load changes, the output voltage significantly drops (through switching losses and non-ideal converter elements). The single-input single-output (SISO) approach with minor-loop voltage feedback controller presented here overcomes this problem. This approach is created on a theoretical linear model and verified by discrete-model simulation on MATLAB/Simulink. The capability and effectiveness of the SISO approach in compensating start-up current/voltage and in achieving zero steady-state error were tested for transient cases with step-changed load and step-changed reference voltage for linear and non-linear loads. Tests were done to analyze the transient performance against various controller gains. An experiment prototype was also developed for verification

Individual student key performance using mobile web apps based on knowledge profile and cumulative grade point average

This study investigated the performance of individual students toward the knowledge profile and cumulative grade point average or known as CGPA. The proposal of this paper involves two major components. The first component is investigating the individual student performance based on the knowledge profile and CGPA. The performance of students from cohort 2017 for the program Bachelor of Electrical Engineering (BEKG) courses in the Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka (UTeM) was used as the dataset. The case study separates into various groups (excellent, honors and pass). Secondly, the study proposed a responsive web application leveraging a Google Visualization Feature to self-check individual academic performance. The goal of this app is to assist users in evaluating individual student performance and assist management in planning for continual quality improvement using the web and mobile apps. The marketing segments include students, academics, university, and school administration for analysis and evaluate the individual student’s performance

A Simple THD Minimization Technique for Transistor-Clamped H-Bridge-Based Cascaded Multilevel Inverter

This paper presents a simple modulation technique that minimizes the output voltage total harmonic distortion (THD) without eliminating the lowest order harmonics. It uses the voltage-angle equal concept of sinusoidal reference waveform to generate the step output voltage of a single-phase transistor-clamped H-bridge (TCHB)-based cascaded multilevel inverter. The real implementation of the modulation technique for a various range of modulation indices is built using an Altera field-programmable gate array (FPGA). It is found that the proposed modulation method resulted in a dramatic decrease in the inverter’s output voltage THD when increasing the number of output steps up to thirteen levels

High frequency signal injection method for sensorless permanent magnet synchronous motor drives

The objective of this project is to design a high frequency signal injection method for sensorless control of permanent magnet synchronous motor (PMSM) drives. Generally, the PMSM drives control requires the appearance of speed and positon sensor to measure the motor speed hence to feedback the information for variable speed drives operation. The usage of the sensor will increase the size, cost, extra hardwire and feedback devices. Therefore, there is motivation to eliminate this type of sensor by injecting high frequency signal and utilizing the electrical parameter from the motor so that the speed and positon of rotor can be estimated. The proposed position and speed sensorless control method using high frequency signal injection together with all the power electronic circuit are modelled using Simulink. PMSM sensorless driveis simulated and the results are analyzed in terms of speed, torque and stator current response without load disturbance but under the specification of varying speed, forward to reverse operation, reverse to forward operation and step change in reference speed. The results show that the signal injection method performs well during start-up and low speed operation

Speed and position estimator of for sensorless PMSM drives using adaptive controller

Nowadays, the elimination of the speed sensor in Permanent Magnet Synchronous Machine (PMSM) is greatly recommended to increase efficiency and reduce the cost of the drives. This paper proposes a simple estimator for speed and rotor position of PMSM drives using adaptive controller. The novelties of the proposed method are the simple estimator equations and the absence of the voltage probe which depend on direct and quadrature reference current only. The simplified mathematical model of the PMSM is formulated by using V-I model, based on adaptive control. Then, the speed estimation error of the voltage and current model based are analyzed. Thus, an adaptation mechanism model is established to cancel the error of the measured and estimated d-q currents. Since the output of the estimator is the position feedback, the performances of speed responses are presented. The hardware implementation of proposed sensorless drives is realized via dSPACE DS11103 panel. dSPACE Real Time Implementation (RTI) is the linkage between software and hardware set-up. It automatically processes the MATLAB Simulink model into dSPACE DS11103 processor. The experimental-hardware results demonstrate that the speed and position estimator of the proposed method is able to control the PMSM drives for forward and reverse of speed command, acceleration, deceleration and robustness to load disturbanc

A simple THD minimization technique for transistor-clamped H-bridge-based cascaded multilevel inverter

This paper presents a simple modulation technique that minimizes the output voltage total harmonic distortion (THD) without eliminating the lowest order harmonics. It uses the voltage-angle equal concept of sinusoidal reference waveform to generate the step output voltage of a single-phase transistor-clamped H-bridge (TCHB)-based cascaded multilevel inverter. The real implementation of the modulation technique for a various range of modulation indices is built using an Altera field-programmable gate array (FPGA). It is found that the proposed modulation method resulted in a dramatic decrease in the inverter’s output voltage THD when increasing the number of output steps up to thirteen levels