The aim of this work is to reduce the cost and size of a brushless dc motor (BLDC) drive as well as increase the reliability and ruggedness of that drive. Traditional BLDC drives use Voltage Source Inverters (VSI) that utilize hard switching, thereby generating switching losses and entail the use of large heatsinks. VSI needs a huge dc link capacitor that is inherently unreliable and is one of the most expensive components of a drive. Hence, a Current Source Inverter (CSI) is used to replace the hard switchings by natural turn-off, thereby eliminating the heatsinks as well as the large dc link capacitor. A controlled rectifier together with a large inductor act as the current source. The only disadvantage is the large value of the dc link inductor and the huge number of turns needed to achieve these values of the inductances lead to huge resistive losses. Therefore, it is shown that it is possible to replace the controlled rectifier and the large inductor with a suitable dc-dc converter based current source switching at high frequencies and a much smaller value of the dc link inductor. Switching at high frequencies makes it possible to reduce the value of the dc link inductor without increasing the current ripple. Hence, it is possible to have the advantages of using a CSI as well as reduce the value of the dc link inductor without a corresponding increase in the heat sink and snubber requirements.

The design and implementation of the digital signal processing (DSP) based on a brushless DC (BLDC) motor sensorless driver with Sine PWM. Because of dispensable power consumption problems generated by closed-loop speed control methods with speed estimation signal feedback are adopted for improvement. In addition, current feedback is added to the driver for the sake of increasing efficiency. Then, sine wave closes 30¢X, 15¢X, and 8¢X to comparing the improvements for efficiency. Experimental results from a laboratory prototype are shown to verify the feasibility of the proposed scheme. The laboratory results show that current feedback and sine wave closed 8¢X have high efficiency.

abstract: The ocean is vital to the health of our planet but remains virtually unexplored. Many researchers seek to understand a wide range of geological and biological phenomena by developing technologies which enable exploration of the deep-sea. The task of developing a technology which can withstand extreme pressure and temperature gradients in the deep ocean is not trivial. Of these technologies, underwater vehicles were developed to study the deep ocean, but remain large and expensive to manufacture. I am proposing the development of cost efficient miniaturized underwater vehicle (mUV) with propulsion systems to carry small measurement devices and enable deep-sea exploration. These mUV's overall size is optimized based on the vehicle parameters such as energy density, desired velocity, swimming time and propulsion performance. However, there are limitations associated with the size of the mUV which leads to certain challenges. For example, 2000 m below the sea level, the pressure is as high as 3000 psi. Therefore, certain underwater vehicle modules, such as the propulsion system, will require pressure housing to ensure the functionality of the thrust generation. In the case of a mUV swimming against the deep-sea current, a thrust magnitude is required to enable the vehicle to overcome the ocean current speed and move forward. Therefore, the size of the mUV is limited by the energy density and the propeller size. An equation is derived to miniaturize underwater vehicle while performing with a certain specifications. An inrunner three-phase permanent magnet brushless DC motor is designed and fabricated with a specific size to fit inside the mUV's core. The motor is composed of stator winding in a pressure housing and an open to water ring-propeller rotor magnet. Several ring-propellers are 3D printed and tested experimentally to determine their performances and efficiencies. A planer motion optimal trajectory for the mUV is determined to minimize the energy usage. Those studies enable the design of size optimized underwater vehicle with propulsion to carry small measurement sensors and enable underwater exploration. Developing mUV's will enable ocean exploration that can lead to significant scientific discoveries and breakthroughs that will solve current world health and environmental problems. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2014

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-12-16T10:26:12Z No. of bitstreams: 2 Dissertação - Renato de Almeida Prado - 2016.pdf: 5947860 bytes, checksum: 8eac741b1f0ab4e9c86905c5865fda99 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2016-12-16T16:49:28Z (GMT) No. of bitstreams: 2 Dissertação - Renato de Almeida Prado - 2016.pdf: 5947860 bytes, checksum: 8eac741b1f0ab4e9c86905c5865fda99 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-12-16T16:49:28Z (GMT). No. of bitstreams: 2 Dissertação - Renato de Almeida Prado - 2016.pdf: 5947860 bytes, checksum: 8eac741b1f0ab4e9c86905c5865fda99 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Permanent Magnet Brushless DC Machine has been used increasingly in numerous applications, such as in industry, transportation systems and wind energy conversion. Given this scenario and the need for knowledge of machine parameters for design purposes, performance analysis and operation of systems, this paper aims to present methodologies and the development of a test system. The test system is based on virtual instrumentation and aims to determine phase resistance, inductances, viscous and static friction coefficients, inertia, and electromotive force and torque constants. In many aspects, the test system is a tool that fills a gap in the area. To check the validity of the obtained parameters and to study machine's perfomance, computer simulations and load tests are performed. / A máquina CC de ímãs permanentes sem escovas (máquina Brushless DC) vem sendo empregada de forma crescente em diversas aplicações, tais como na indústria, nos sistemas de transporte e na conversão de energia eólica. Tendo em vista esse cenário e a necessidade do conhecimento dos parâmetros da máquina para fins de projeto, análise de desempenho e operação dos sistemas, esse trabalho tem como objetivo a apresentação de metodologias e o desenvolvimento de um sistema de ensaio. Tal sistema é baseado em instrumentação virtual e visa o levantamento da resistência de fase, indutâncias, coeficientes de atrito viscoso e estático, inércia e constantes de força eletromotriz e de torque. Sob muitos aspectos, tem-se uma ferramenta que preenche uma lacuna atual na área. Para a verificação dos parâmetros obtidos e estudo de seu rendimento, são realizadas simulações computacionais e ensaios em carga.

Small scale unmanned aircraft, such as quadrotors, that are quickly emerging as versatile tools for a wide range of applications including search and rescue, hazardous environment exploration, or just shooting great video, are known as micro air vehicles (MAVs). However, for millimeter scale vehicles with weights under 10 grams, conventional flight technologies become greatly inefficient and instead inspiration is drawn from biology. Flapping wing MAVs (FWMAVs) have been created based on insects and hummingbirds in an effort to emulate their extreme agility and ability to hover in place. FWMAVs possess unique capabilities in terms of maneuverability, small size, and ability to operate in dynamic environments that make them particularly well suited for environmental monitoring and swarm applications such as artificial crop pollination. Despite their advantages, significant challenges in fabrication, power, and control must be overcome in order to make FWMAVs a reliable platform. Current designs suffer from high mechanical complexity and often rely on off-board power, sensing, and control, which compromises their autonomy and limits practical applications. The goal of my research is to develop a simple FWMAV design that provides high efficiency and controllability. An efficient, simple, and controllable vehicle design is developed utilizing the principles of resonance, emulation of biological flight control, and under-actuation. A highly efficient, resonant actuator is achieved by attaching a spring in parallel to the output shaft of a commercial geared DC micro-motor. This actuator directly drives the wings of the vehicle, allowing them to be controlled precisely and independently. This direct control strategy emulates biology and differs from other FWMAV designs that utilize complicated transmissions to generate flapping from rotary motor output. Direct control of the wings allows for emulation of biological wing kinematics, resulting in control based on wing motion alone. Furthermore, under-actuation is employed to mimic the rotational motion of insect wings. A rotational joint is added between the motor and wing membrane such that the wing rotates passively in response to aerodynamic forces that are generated as the wing is driven. This design is realized in several stages, initial prototyping, simulation and development of the actuator and wings, then finally a control system is developed. First the system was modeled and improved experimentally in order to achieve lift off. Improvements to the actuator were realized through component variation and custom fabrication increasing torque and power density by 161.1% and 666.8% respectively compared to the gearmotor alone and increased the resonant operating frequency of the vehicle from 4 Hz to 23 Hz. Advances in wing fabrication allowed for flexible wings that increased translational lift production by 35.3%, aerodynamic efficiency by 41.3%, and the effective lift coefficient by 63.7% with dynamic twisting. A robust control architecture was then developed iteratively based on a date driven system model in order to increase flight time from 1 second (10 wing strokes) to over 10 seconds (230 wing strokes). The resulting design improves lift to weight by 166%, allowing for a payload capacity of approximately 8.7 g and offers the potential for fully autonomous operation with all necessary components included on-board. A thermal model for micro-motors was developed and tuned to accurately predict an upper limit of system operation of 41 seconds as well as to optimize a heatsink that increases operating time by 102.4%.

Today, tightening tools are widely used in the industry and on the market you will find several products that have been assembled with the help of tightening tools. For example, tightening tools are used in the automotive industry and when assembling computer hardware. It is important that the tightening tools are robust and of high quality in order to fulfil the demanded requirements. High assembly speed has entailed an extensive use of tightening tools. To ensure that the tightening tools have the desired properties, tightening tools are tested continuously using so-called test systems. This puts high demands on the test systems since it is of importance that the tightening tools can be tested in a simple, fast and reliable way as well as repeatedly. Therefore, Atlas Copco would like to investigate whether a test system constructed with an electrical motor is a good choice. The idea of this thesis is to investigate possibilities and limitations in a test system consisting of an electrical motor that emulates the behaviour of a screw joint. To be able to investigate hardware limitations a test rig is constructed and then modelled in MATLAB. Further, simulations have been carried out in order to analyse the possibilities and limitations of such a test rig. The conclusion is that the implemented LQ controller seems to be able to control the braking motor sufficiently like a screw joint.

The use of brushless motors has increased in recent years due to superior performance characteristics compared with alternatives. The operation of a brushless motor is dependent upon a separate controller which is often in the form of a printed circuit board. As such, the size and performance capability of the controller can restrict the performance of the overall motor control system so advancements of these controllers further the potential use of BLDC motors. This project outlines the design of a PCB based, sensorless motor controller for operation of a three-phase BLDC motor powered by a 24 V, high current external supply. Components used were selected to withstand an ambient temperature environment of 125 degrees C. The design for this PCB based motor control system was completed but fabrication and testing of the system was prevented by COVID-19 related restrictions that prohibited the use of necessary facilities and equipment. The detailed design including component selection, board layout, and software development is included in addition to a plan for fabrication and fundamental functional testing. Although no results are available for analysis to bring about any conclusions, a variety of design strategies and corresponding learnings hold the potential to be a source of valuable reference to the further study and development of future designs.

This thesis deals with the optimization of state space controller of DC motor on FPGA in LabVIEW environment on NI cRIO platform. In the first part, the state space model of the given DC motor is presented in Matlab/Simulink and then the position feedback controller with steady-state error elimination and with state observer with error compen-sation using LQR method is designed. The thesis continues with transforming the con-troller to LabVIEW environment where the code is edited for FPGA use. Next, the fo-cus on FPGA hardware resources consumption optimization leads to careful work with fixed-point data type. After successful code compilation on target hardware, the real given DC motor is connected and the series of tests are performed. The output of the thesis is working state space controller running on FPGA and the graphical user inter-face on real-time host cRIO, which enables the user to control the plant and save the data on the disk.

Construction of motor models is the main topic of this project. Mathematical characterization of AC machine, permanent magnet synchronous motor, separately-excited DC motor, series-wound DC motor, permanent magnet DC motor, switched reluctance motor is also described. Design of models is based on mathematical description of particular motors. Models are created in Matlab Simulink. Each model is implemented in continuous and also in discrete time variant. Selected models are implemented also on processor from Freescale 56F800E Hybrid Controller family. Each model has individual graphic user interface. Besides motor models, there is description and easy algorithm of Space Vector Modulation. Model of this method is also created. Models are build-up into a library, which can be used for simulations and tests of control structures. Results of models simulations are presented at the end of this project. Simulation of models that are implemented on processor is also made in Matlab Simulink environment and is compared to simulation of models that are implemented directly in Matlab Simulink.

This master thesis deals project and realization of universal transistor converter for power electronics course. For this converter was at the same time designed control circuit and drive circuit. Next part is about the design of compact converter for DC. This converter is controlled by a microprocessor Freescale.