Implementation of a motor controller

Master's thesis in Automation and signal processingThis thesis is written for E Plug, a company that specialises in down-hole operations in the oil industry. Brushless DC (BLDC) motors are being used almost everywhere in todays market. The BLDC motor can be found in vacuum cleaners, dryers, air conditioners, electrical bikes, medical equipment, aerospace technology etc. It is now increasingly being used in the oil industry. The BLDC motor is known to be efficient, silent, compact and has a long operational lifetime and reduced maintenance time compared to other DC motors. Because of the lack of brushes, the motor is optimal to use in the oil industry as it won’t generate any dangerous sparks which can be a problem with brushed motors. The challenge with a brushless motor is that it requires an efficient driving code implemented in a microcontroller. The rotor position is unknown and the motor need some sort of logic to determine the position, so that it knows when to give the rotor a "push”. The brushed motors are easier to control as the brushes constantly provides feeback on where the rotor is. In this thesis three different driving codes are implemented in a microcontroller, tested and analysed. The first method is sensorless control, which is based on back-EMF detecting. This method provides an unstable and unpredictable start up time for the motor, as back-EMF sensing isn’t available on low speed operations. The second methods uses Hall-effect sensors which gives feedback on where the rotor is. This method provides a stable response and is very effective. The third method uses an optical encoder with a more complex code that takes use of the benefits of shunt resistors. By sensing the phase currents and using the measurements to control the stators magnetic field, the motor can be regulated to operate at it’s maximum torque per amp. This method shows to be clearly the most precise and effective way of controlling the motor. A use of resolver for detecting rotor position was planned to be implemented. Because of the hardware needed for this control wasn’t available, it had to be discarded. As most of the time working on the thesis went to implementing the different methods, there wasn’t so much time as hoped to analyse the results. One of the other goals was to implement the different methods on a second microcontroller, which is based on floating-point unit instead of fixed-point unit. As this task became too extensive, this goal was discarded as well.E Plu

High performance position control for permanent magnet synchronous drives

In the design and test of electric drive control systems, computer simulations provide a useful way to verify the correctness and efficiency of various schemes and control algorithms before the final system is actually constructed, therefore, development time and associated costs are reduced. Nevertheless, the transition from the simulation stage to the actual implementation has to be as straightforward as possible. This document presents the design and implementation of a position control system for permanent magnet synchronous drives, including a review and comparison of various related works about non-linear control systems applied to this type of machine. The overall electric drive control system is simulated and tested in Proteus VSM software which is able to simulate the interaction between the firmware running on a microcontroller and analogue circuits connected to it. The dsPIC33FJ32MC204 is used as the target processor to implement the control algorithms. The electric drive model is developed using elements existing in the Proteus VSM library. As in any high performance electric drive system, field oriented control is applied to achieve accurate torque control. The complete control system is distributed in three control loops, namely torque, speed and position. A standard PID control system, and a hybrid control system based on fuzzy logic are implemented and tested. The natural variation of motor parameters, such as winding resistance and magnetic flux are also simulated. Comparisons between the two control schemes are carried out for speed and position using different error measurements, such as, integral square error, integral absolute error and root mean squared error. Comparison results show a superior performance of the hybrid fuzzy-logic-based controller when coping with parameter variations, and by reducing torque ripple, but the results are reversed when periodical torque disturbances are present. Finally, the speed controllers are implemented and evaluated physically in a testbed based on a brushless DC motor, with the control algorithms implemented on a dsPIC30F2010. The comparisons carried out for the speed controllers are consistent for both simulation and physical implementation

Design and Control of Electrical Motor Drives

Dear Colleagues, I am very happy to have this Special Issue of the journal Energies on the topic of Design and Control of Electrical Motor Drives published. Electrical motor drives are widely used in the industry, automation, transportation, and home appliances. Indeed, rolling mills, machine tools, high-speed trains, subway systems, elevators, electric vehicles, air conditioners, all depend on electrical motor drives.However, the production of effective and practical motors and drives requires flexibility in the regulation of current, torque, flux, acceleration, position, and speed. Without proper modeling, drive, and control, these motor drive systems cannot function effectively.To address these issues, we need to focus on the design, modeling, drive, and control of different types of motors, such as induction motors, permanent magnet synchronous motors, brushless DC motors, DC motors, synchronous reluctance motors, switched reluctance motors, flux-switching motors, linear motors, and step motors.Therefore, relevant research topics in this field of study include modeling electrical motor drives, both in transient and in steady-state, and designing control methods based on novel control strategies (e.g., PI controllers, fuzzy logic controllers, neural network controllers, predictive controllers, adaptive controllers, nonlinear controllers, etc.), with particular attention to transient responses, load disturbances, fault tolerance, and multi-motor drive techniques. This Special Issue include original contributions regarding recent developments and ideas in motor design, motor drive, and motor control. The topics include motor design, field-oriented control, torque control, reliability improvement, advanced controllers for motor drive systems, DSP-based sensorless motor drive systems, high-performance motor drive systems, high-efficiency motor drive systems, and practical applications of motor drive systems. I want to sincerely thank authors, reviewers, and staff members for their time and efforts. Prof. Dr. Tian-Hua Liu Guest Edito

Critical Aspects of Electric Motor Drive Controllers and Mitigation of Torque Ripple - Review

Electric vehicles (EVs) are playing a vital role in sustainable transportation. It is estimated that by 2030, Battery EVs will become mainstream for passenger car transportation. Even though EVs are gaining interest in sustainable transportation, the future of EV power transmission is facing vital concerns and open research challenges. Considering the case of torque ripple mitigation and improved reliability control techniques in motors, many motor drive control algorithms fail to provide efficient control. To efficiently address this issue, control techniques such as Field Orientation Control (FOC), Direct Torque Control (DTC), Model Predictive Control (MPC), Sliding Mode Control (SMC), and Intelligent Control (IC) techniques are used in the motor drive control algorithms. This literature survey exclusively compares the various advanced control techniques for conventionally used EV motors such as Permanent Magnet Synchronous Motor (PMSM), Brushless Direct Current Motor (BLDC), Switched Reluctance Motor (SRM), and Induction Motors (IM). Furthermore, this paper discusses the EV-motors history, types of EVmotors, EV-motor drives powertrain mathematical modelling, and design procedure of EV-motors. The hardware results have also been compared with different control techniques for BLDC and SRM hub motors. Future direction towards the design of EV by critical selection of motors and their control techniques to minimize the torque ripple and other research opportunities to enhance the performance of EVs are also presented.publishedVersio

Milestones, hotspots and trends in the development of electric machines

As one of the greatest inventions of human beings, the electric machine (EM) has realized the mutual conversion between electrical energy and mechanical energy, which has essentially led humanity into the age of electrification and greatly promoted the progress and development of human society. This paper will briefly review the development of EMs in the past two centuries, highlighting the historical milestones and investigating the driving force behind it. With the innovation of theory, the progress of materials and the breakthrough of computer science and power electronic devices, the mainstream EM types has been continuously changing since its appearance. This paper will not only summarize the basic operation principle and performance characteristics of traditional EMs, but also that of the emerging types of EMs. Meanwhile, control and drive system, as a non-negligible part of EM system, will be complementarily introduced. Finally, due to the background of global emission reduction, industrial intelligentization and transportation electrification, EM industry will usher again in a golden period of development. Accordingly, several foreseeable future developing trends will be analyzed and summarized

Simulation of Electromechanically Actuated Boom

Environmental consciousness has made electrification of mobile machines a popular trend in recent years. Electromechanical linear actuators (EMLAs) may be used to replace hydraulic cylinders in mobile machines. In this thesis a simulation model for a boom with single EMLA is developed. The EMLA consists of a permanent magnet synchronous motor (PMSM), gearbox and ball screw. The objective of this thesis is to develop a simulation model that includes the EMLA, the control system and the mechanical model of the boom. The simulations are carried out in Matlab Simulink environment. The simulation model is validated by comparing simulation results with measurement data of the actual system. Structure, operating principle, mathematical equations and common control structure of PMSM are introduced to develop a simulation model for the motor and motor controller. The motor used in this thesis uses Hall sensors as feedback device. The downsides and challenges of using such low-resolution sensors are also covered in this thesis. A spring-mass model is used to model the mechanics of the actuator. The equations to obtain parameters for the spring mass models are introduced. Friction of the actuator is also studied, and it is found out that there are no friction models that could predict the friction accurately using basic parameters of the ball-screw. There are many components corresponding to total friction and developing an experimental model is the best option. A simple assumption of constant efficiency of the actuator is used in this thesis. The simulation model of the motor and motor controller was validated independently of the rest of the system by utilizing a motor test bench. It was found out that the models are sufficiently accurate to be used for complete system modelling, including the EMLA and the boom. The complete model was then developed, and the results were compared with measurement data from the real system. The results showed similarities and the simulator managed to show controllability issues of the real system. The issues were caused by slow control loop frequency and delay in the control loop. To improve the systems performance a motor and a motor controller better suited for motion control applications should be used. It was found out that the simple friction model used is not accurate and a better model should be developed

Advances in Rotating Electric Machines

It is difficult to imagine a modern society without rotating electric machines. Their use has been increasing not only in the traditional fields of application but also in more contemporary fields, including renewable energy conversion systems, electric aircraft, aerospace, electric vehicles, unmanned propulsion systems, robotics, etc. This has contributed to advances in the materials, design methodologies, modeling tools, and manufacturing processes of current electric machines, which are characterized by high compactness, low weight, high power density, high torque density, and high reliability. On the other hand, the growing use of electric machines and drives in more critical applications has pushed forward the research in the area of condition monitoring and fault tolerance, leading to the development of more reliable diagnostic techniques and more fault-tolerant machines. This book presents and disseminates the most recent advances related to the theory, design, modeling, application, control, and condition monitoring of all types of rotating electric machines

An assessment of flywheel storage for efficient provision of reliable power for residential premises in islanded operation

Energy storage systems (ESS) are key devices for improving power quality, electrical system stability and system efficiency by contributing to the balance of supply and demand. They can enhance the flexibility of electrical systems by mitigating supply intermittency, which has recently become problematic due to the increased penetration of renewable generation. The subject of this thesis is flywheel energy storage system (FESS), a technology that is gathering great interest due to benefits offered over alternative energy storage solutions, including high cycle life, long calendar life, high round‐trip efficiency, high power density, operation at high ambient temperatures and low negative environmental impact. This thesis describes the modelling and assessment of small scale energy system incorporating FESS with solar photovoltaic (PV) and a diesel generator for use in islanded residential premises with highly intermittent or non‐existent grid infrastructure. In this application, incorporation of FESS is shown to be beneficial in comparison to a system without storage or one with the alternative storage technology, Li‐Ion batteries. The thesis begins with a description of flywheel storage systems configured for electrical storage which comprises of a mechanical part; flywheel rotor, bearings and containment, and an electric drive part; motor‐generator and associated power electronics. Each of these components is described in the thesis along with the equations and modelling, itself carried out in the MATLAB/Simulink environment. Finally, the flywheel model is combined with a model of an islanded residential power system incorporating a solar PV system with a diesel generator. Such a system would be particularly useful for offgrid applications or those with weak grids as occurs in developing countries