This master's thesis aims to establish a foundation for model-based engineering of drill rigs through the development, evaluation, and utilization of simulation models. Specifically, the project focused on creating a simulation model of the hydraulic tramming system in the SmartRoc D65 surface drill rig. The uncalibrated model was validated against physical tests conducted on the SmartRoc T35 drill rig, and the results provided accurate predictions with some room for improvement. The model sets a basis for identifying power losses and future potential optimization through electrification. A modeling methodology was developed to aid in the development of other simulation models representing a physical system. The thesis highlights the strengths and limitations of a quasi-static model when applied to dynamic systems. The findings suggest areas for future improvement and underscore the importance of continuous model refinement to enhance calculation accuracy.

Characterizing  power  switches  is  an  indispensable  step  when  designing  a  converter.  This  thesisinvestigates ways to achieve static and dynamic characterization of semiconductors for high power applications such as power grid or train traction. The static characterization has been tested with a Keysight B1506A device analyzer. The problems encountered have been analyzed and corrected.Then the design of a high current switching test bench for dynamic characterization is explained. The full-bridge  configuration  allows  controlled  and  spontaneous  commutations  so  the  bench  can measure hard and soft switching. The voltage can be up to 10 kV and the current up to 3 kA during the commutation. The choice of the probes is justified. The issues of bandwidth, input impedance and common mode current are taken into account. Data are processed in order to interpolate theswitching loss in hard and soft switching. / Karaktärisering  av  halvledarbrytare  är  ett  viktigt  steg  när  man  utformar  en  omvandlare.  Dennaavhandling undersöker olika sätt att uppnå statisk och dynamisk karakterisering av halvledare för högeffekttillämpningar såsom elnät eller ellok. Statisk karaktäriseringen har utförts med en Keysight B1506A-enhetsanalysator. De problem som uppstått har analyserats och korrigerats.Utformningen    av    en    testbänk    för    dynamisk    karakterisering    förklaras.    Den    kompletta bryggkonfigurationen möjliggör kontrollerad och spontan kommutation med spänningar upp till 10 kV och  strömmar  upp till 3 kA så att  bänken kan mäta hård  och mjuk  växling.  Valet  av sonderna förklaras.   Frågorna   om   bandbredd,   ingångsimpedans   och   common-mode   ström   tas   med   iberäkningen. Data bearbetas för att interpolera kopplings förlusten i hård och mjuk växling.

This research presents a Hybrid Particle Swarm Optimization with Bat Algorithm (HPSOBA) based approach to solve Optimal Reactive Power Dispatch (ORPD) problem. The primary objective of this project is minimization of the active power transmission losses by optimally setting the control variables within their limits and at the same time making sure that the equality and inequality constraints are not violated. Particle Swarm Optimization (PSO) and Bat Algorithm (BA) algorithms which are nature-inspired algorithms have become potential options to solving very difficult optimization problems like ORPD. Although PSO requires high computational time, it converges quickly; while BA requires less computational time and has the ability of switching automatically from exploration to exploitation when the optimality is imminent. This research integrated the respective advantages of PSO and BA algorithms to form a hybrid tool denoted as HPSOBA algorithm. HPSOBA combines the fast convergence ability of PSO with the less computation time ability of BA algorithm to get a better optimal solution by incorporating the BA’s frequency into the PSO velocity equation in order to control the pace. The HPSOBA, PSO and BA algorithms were implemented using MATLAB programming language and tested on three (3) benchmark test functions (Griewank, Rastrigin and Schwefel) and on IEEE 30- and 118-bus test systems to solve for ORPD without DG unit. A modified IEEE 30-bus test system was further used to validate the proposed hybrid algorithm to solve for optimal placement of DG unit for active power transmission line loss minimization. By comparison, HPSOBA algorithm results proved to be superior to those of the PSO and BA methods. In order to check if there will be a further improvement on the performance of the HPSOBA, the HPSOBA was further modified by embedding three new modifications to form a modified Hybrid approach denoted as MHPSOBA. This MHPSOBA was validated using IEEE 30-bus test system to solve ORPD problem and the results show that the HPSOBA algorithm outperforms the modified version (MHPSOBA). / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)

Three-level diode-clamped inverter is being widely used these days. Extensive research has been carried out on pulse width modulation (PWM) strategies for a three-level inverter. The most widely used PWM strategies are sine-triangle pulse width modulation (SPWM) and centered space vector pulse width modulation (CSVPWM). The influence of these PWM strategies on the DC-link capacitor current and voltage ripple is studied in this thesis. The sizing of the DC capacitor depends on value of the maximum RMS current flowing through it. In this work, an analytical expression for capacitor RMS current is derived as a function of operating conditions like modulation index, power factor angle of the load and peak load current. The worst case current stress on the capacitor is evaluated using the analytical expression. The capacitor RMS current is found to be the same in SPWM and CSVPWM schemes. The analytical expression is validated through simulations and experiments on a 3kVA MOSFET based three-level inverter. Harmonic analysis of the capacitor current is helpful in better evaluation of capacitor power loss. Therefore, harmonic analysis of the capacitor current is carried out, using the techniques of geometric wall model and double Fourier integral for SPWM and CSVPWM schemes. The theoretical predictions are validated through experiments. The capacitor RMS current is divided into low-frequency RMS current (where low frequency component is defined as a component whose frequency is less than half the switching frequency) and high-frequency RMS current. The capacitor voltage ripple is estimated analytically for SPWM and CSVPWM schemes, using the low-frequency and high-frequency capacitor RMS current. The voltage ripples due to SPWM and CSVPWM schemes are compared. It is found that the voltage ripple with SPWM is higher than that with CSVPWM. A simplified method to estimate the capacitor power loss, without the requirement of FFT analysis of capacitor current, is proposed. The results from this simplified method agree reasonably well with the results from the detailed method. A space vector based modulation scheme is proposed, which reduces the capacitor RMS current at high power factor angles. However, the proposed method leads to higher total harmonic distortion (THD) than CSVPWM. Simulation and experimental results, comparing CSVPWM and the proposed PWM, are presented.