The TI TMS320LF2407A DSP is used as the control kernel in this thesis, proposing a method of sensorless control for the brushless DC motor. With six-step pulse-width modulation, the information of the back electromagnetic signals can be detected and is used to estimate the rotor position instead of the Hall sensors. To strengthen the system and reduce the power consumption, we propose the idea of close loop framework, including speed feedback and current feedback. Then, the phase-change signal is set as no delayed, 15 degree delayed, and 30 degree delayed and compare the results each other. Finally, setting up experimental framework, to verify the superiority of sensorless drivers with close-loop framework, and choosing better phase-change degree to improve system and efficiency.

This thesis focuses on compact brushless DC fan motor, drive circuit structure of motor is proposed, several functions such as output low current limit circuit and low rotation speed limit are added in order to increase robustness of drive circuit. Besides, speed feedback controller is used to solve several problems such as high frequency full speed exciting noise and high power dissipation which occurs in open loop rotation speed control circuit.With regard to BLDC fan motors generally use Hall sensor to detect rotor position, this research proposes sensorless control technology for the purpose of reducing circuit cost and motor size.

This thesis focues on the realization of small size brushless DC fan motor driving circuit, adding the protection circuit of commutation to H bridge, in addition, the function of low current limiter, and slow rotation speed limiter are also implemented to the more stable rotation. With regard to the strategy of rotation speed control, we use speed feedback controller to slove noise problem which occurs in high frequency full speed excited and adopt thermistor accompanied with the voltage divided circuit to achieve speed control with temperature. Finally, for the sake of reducing the cost and shrinking the size of system, the design of sensorless mode is proposed and the rotation speed control system is realized under sensorless mode.

This thesis includes two research topics. The first topic is a low-power 2-dimensional bypassing digital multiplier design. The second one is a low-power sensorless micro-controller for brushless DC motors (BLDCM). The low-power 2-dimensional bypassing digital multiplier takes advantage of a 2-dimensional bypassing method. The proposed bypassing cells constituting the multiplier skip redundant signal transitions when the horizontally partial product or the vertically operand is zero. Hence, it is a 2-dimensional bypassing architecture. Thorough post-layout simulations show that the power dissipation of the proposed 8 ¡Ñ 8 design is reduced by more than 75% compared to the prior 8 ¡Ñ 8 design with obscure cost of delay and area. The goal of the low-power sensorless micro-controller for brushless DC motors is to design a BLDCM controller without using any Hall sensor. Back-EMF estimation method using the terminal voltage sensing is adopted for the detection of the commutation moment for the proper commutation control of the BLDCM. The position of the rotor can be precisely estimated by measuring the back-EMF as well as the zero-crossing points.

Thesis deals with the challenges in the field of BLDC motors control with the utilization of Field Programmable Gate Arrays (FPGA). Using the modular dSPACE hardware with the FPGA board, these issues are solved: sensored and sensorless control, real-time simulation of BLDC motor and control of BLDC motor in degraded mode. FPGA design is made using the System Generator for DSP from Xilinx. The side effect of work is to show that with the expansion of high-level tools for FPGA design, the implementation of algorithms for FPGA is relatively quick and efficient and does not require years of experience and big knowledge of field programmable gate arrays. The implementation of algorithms on FPGA instead of processors brings many advantages, in the first place the high speed processing and low latency.

In this thesis axial flux and radial flux brushless dc motors will be studied as a drive motor for the control of moment gyroscope wheel. Design equations for axial flux and radial flux brushless dc motor topologies will be reviewed. Based on these equations radial and axial flux motors with different number of poles will be designed that meet control moment gyroscope wheel application requirements. The results will be evaluated in terms of efficiency, torque/mass and torque/volume, and suitability for the control moment gyroscope application.

<p>This report presents the work carried out aiming towardsdistributed control of electric drives through a networkcommunication medium with temporal constraints, i.e, Ethernet.A general analysis on time delayed systems is carried out,using state space representation of systems in the discretetime domain. The effect of input time delays is identified andis used in the preceding controller designs. The main hardwareapplication focused in this study is a Brushless DC servomotor, whose speed control loop is closed via a 10 MbpsSwitched Ethernet network. The speed control loop, which isapproximately a decade slower than the current control loop, isopened and interfaced to the network at the sensor/actuatornode. It is closed at the speed controller end at another nodein the same local area network (LAN) forming a distributedcontrol system (DCS).</p><p>The Proportional Integral (PI) classical controller designtechnique with ample changes in parameter tuning suitable fortime delayed systems is used. Then the standard Smith Predictoris tested, modified with the algebraic design techniqueCoefficient Diagram Method (CDM), which increases the systemdegrees of freedom. Constant control delay is assumed in thelatter designs despite the slight stochastic nature in thetiming data observations. Hence the poor transient performanceof the system is the price for the robustness inherited to thespeed controllers at the design stage. The controllability andobservability of the DCS may be lost, depending on the range inwhich the control delay is varying. However a state feedbackcontroller deploying on-line delay data, obtained by means ofsynchronizing the sensor node and controller node systemclocks, results in an effective compensation scheme for thenetwork induced delays. Hence the full state feedbackcontroller makes he distributed system transient performanceacceptable for servo applications with the help of poleplacement controller design.</p><p>Further, speed synchronizing controllers have been designedsuch that a speed fluctuation caused by a mechanical loadtorque disturbance on one motor is followed effectively by anyother specified motor in the distributed control network with aminimum tracking or synchronizing error. This type ofperformance is often demanded in many industrial applicationssuch as printing, paper, bagging, pick and place and materialcutting.</p><p><b>Keywords:</b>Brushless DC Motor, Control Delay, DistributedMotion Control Systems, Proportional Integral Controller, SmithPredictor, Speed Synchronization, State Feedback Controller,Stochastic Systems, Switched-Ethernet, Synchronizing Error,Time Delayed Systems, Tracking Error</p>

A high temperature magnetic bearing system using high temperature permanent magnets from Electron Energy Corporation (EEC) is under development. The system consists of two radial bearings, one thrust bearing, two radial catcher bearings and one motor. The purpose of this research is to develop one of the critical components of the system, namely, the High Temperature Permanent Magnet motor. A novel High Temperature Permanent Magnet (HTPM) Brushless DC(BLDC) motor capable of operating at 1000 degrees F (538 degrees C) is designed. HTPMs developed at Electron Energy Corporation are buried into the rotor. The high temperature motor is designed to produce 5.1kw of power at a top running speed of 20000 rpm. The numerical values of the motor voltage, power and torque output are predicted from calculations of the nonlinear finite element model of the motor. The motor stator is wound, potted, cured and high potential tested at 1000 degrees F. A servo amplifier from Advanced Motion Control is used to drive the high temperature motor. High temperature displacement sensors are set up for sensing the rotor position to form a closed loop motion control. However, the noise problem of the high temperature sensors causes a failure of this approach. An open loop approach is then developed and this approach succeeds in spinning the rotor with the capability of self-starting. The status of the full system assembling is introduced. Some other components of the system are briefly presented.

In this thesis, position and current control systems for a brushless DC (Direct Current) motor are designed and integrated into one FPGA (Field Programmable Gate Array) chip. Experimental results are obtained by driving the brushless DC motors of Control Actuation System of a guided missile. Because of their high performance, brushless DC motors are widely used in Control Actuation Systems of guided missiles. In order to control the motor torque, current controller is designed and implemented in the FPGA. Position controller is designed to fulfill the position commands. A soft processor in the FPGA is used to connect and configure the current controller, position sensor interfaces and communication modules such as UART (Universal Asynchronous Receiver Transmitter) and Spacewire. In addition / position controller is implemented in the soft processor in the FPGA. An FPGA based electronic board is designed and manufactured to implement control algorithms, power converter circuitry and to perform other tasks such as communication with PC (Personal Computer). In order to monitor the behavior of the controllers in real time and to achieve performance tests, a graphical user interface is provided.

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.