A new hybrid machine having variable reluctance and permanent magnets (PMs) is presented. The machine makes use of the features of a PM machine and variable reluctance machine. The resulting machine is doubly salient and has a structure free of flux reversals. Unlike conventional doubly salient permanent magnet machines (DSPMs), the one proposed in this report is driven by unipolar currents and uses an asymmetric converter which is used to drive switched reluctance machines. The reason to have a new hybrid machine without the drawbacks of conventional flux-reversal-free-stator SRMs and conventional DSPMs is also described. Conventional doubly salient permanent magnet machines which are driven by alternating currents, do not use reluctance torque and have flux reversals in the stator iron. Homopolar flux at the peak flux density lowers hysteresis and eddy-current loss, since the machine's core operates in only one magnetizing quadrant. Due to unbalanced forces in conventional stator-flux-reversal-free machines, their deployment in industrial and end-user applications has been hindered. The presented hybrid machine has balanced radial forces. Therefore, it maintains the advantages of conventional stator-flux-reversal-free machines while shedding its disadvantages. The proposed machine has significantly increased power density and is more electromechanically efficient than its predecessor. A experimental prototype motor has been designed and built. Its static torque characteristics correlated well with predicted data. Experimental operation of the drive under open loop speed control shows the efficiency to be 90.8% under non-ideal driving conditions. In the current energy conscious environment and market, this motor because of its high efficiency has a significant role in reducing the energy consumption in household, industrial and automotive applications requiring electric motors. / Ph. D.

The researchers at the Department of Electricity at Uppsala University has recently entered the field of electric motor design, however no real knowledge of motor control of salient pole permanent magnet motors exists in the department. This thesis will present a general description of the control method of motors that exist today, this has been done by reviewing existing literature. The literature review has shown that there are at least three control methods with a significant different in their control approach, Scalar-, Field Oriented- and Direct Torque- Control. The two last methods were chosen by the author as the most useful and was implemented and simulated together with the newly developed motor in MATLAB Simulink to evaluate their performance. The simulation results show that there is no difference in performance of the two methods, but they show a difference in efficiency. The results show that it's worth to develop both methods further, mainly for reducing the torque and current ripple. This result was not expected according to literature, which suggests that the Field Oriented Control has a lower torque ripple. This could be caused by the choice of hysteresis control for inverter switching, instead of more sophisticated methods with a proportional integral derivative controller (PID) together with Sinusoidal Pulse Width Modulation (SPWM) or Space Vector Modulation (SVM).

This study analyzes the performance of variable capacity heat pump scroll compressor which is equipped with vapour injection and permanent magnet motor. Refrigerant used in the system is R410A. The study is divided in two phases. In first phase, tests are carried out for heat pump without vapour injection. Heat pump’s performance including COPs, heating/cooling capacities, inverter losses, heat transfer behaviour in condenser/evaporator are analyzed. Inverter losses increase but the ratio of inverter losses to the total compressor power decreases with increase in compressor speed. Electromechanical losses of compressor are much higher than the inverter losses and so make most part of the total compressor losses (summation of inverter and electromechanical losses). In second phase benefits of vapour injection are analyzed. For vapour injection, heat pump’s performance is evaluated for two different refrigerant charges: 1.15kg and 1.28kg. It is noted that heat pump performs better for refrigerant charge 1.15kg even at lower compressor speeds as compared to refrigerant charge 1.28kg. For refrigerant charge 1.15kg, heat pump COP cool with vapour injection increases by an average of 10.66%, while COP heat increases by an average of 9.4%, at each compressor speed except for 30Hz, as compared to conventional heat pump cycle with no vapour injection. Similarly refrigerant temperature at outlet of compressor also reduces with vapour injection which leads to the better performance of heat pump.

The evolution of aircraft has led into a large increase in the demand for electrically integrated subsystems. Part of this demand is the transformation of a centralized hydraulic systems to independently operated electrical subsystems. The result of this overhaul will decrease aircraft weight, increase reliability, reduce aircraft lifetime maintenance and cost, and help to increase the control of power distribution. This thesis proposes the design methodology of a multi-pole permanent magnet (PM) motor with a capability to operate at high temperature. High temperature capability is one of the key requirements to implement electromechanical actuation for aircraft flight control, replace hydraulic actuation system, especially in tactical military aircraft, due to the hot environment and lack of heat sink. Temperature effects on motor materials are reviewed. The need for high power density is considered in the design. The motor design is confirm by ANYSYS RMXprt software. Along with the motor design, a voltage control method is also designed for the motor. Integrated electrical simulation results of the motor and controller to follow highly dynamic flight profiles are provided to show the stroke tracking, input power (including regenerative power), and winding copper loss. Experimentation set-up of EMA and experimental uncertainties are also discussed.

Examensarbetet var en utvärdering av en synkron trefas permanentmagnetmotor med utvändig rotor. Den är tänkt att ingå i ett batterimatat drivsystem för hjälputrustning på segelbåtar. Målen var att kartlägga prestandan i standardutförande samt att hitta de svaga punkterna i konstruktionen. Förslag på hur motorutförandet kan optimeras ska också läggas fram.   Tester och mätningar gjordes i en testuppkoppling med växelriktare, motor och axelkopplad generator. Detta för att kunna få fram fler mätvärden på motorn. Generatorn fick varvtalskortslutning när belastningsströmmen kom upp i 106,1 A och testerna fick avslutas. Koppartråden i lindningarna blev för varm och ytskiktet smälte. Testerna visar att motorn klarar av strömmar upp till 92,1 A och har då en verkningsgrad på 70 %. Det var lindningens strömtålighet tillsammans med effektförlusterna som var den begränsande faktorn i motorkonstruktionen.   Forcerad kylning i form av vattenkyld stator eller att öka lindningstrådens strömtålighet genom att t.ex. en större kabelarea är alternativ för att få till en bättre verkningsgrad och motorprestanda. Ser man till externa lösningar skulle luftkylning med fläkt kunna adderas. / The project was to evaluate a synchronous three-phase permanent magnet motor with brushless outrunner. It is supposed to be a part of an electric drive system for equipment onboard sailing boats. The goal was to investigate the performance of the motor and find the construction weaknesses and to come up with suggestions how to optimize the performance of the motor.   Tests and measurements were made with a test setup that consisted of inverter, motor and a generator connected to the shaft. The generator stator winding had a short circuit when the load current reached 106,1 A and the tests therefore had to end. The copper wire used in the windings temperature became to high and the isolation of the wire melted.  The tests showed that the motor could handle up to 92,1 A with an efficiency of 70%. It was how much current the winding could withstand together with the power losses that was the limiting factor of the motor construction.   Forced cooling with water cooled stator or improving the winding wires ability to handle higher currents by increasing the cable area are both alternatives to get a better efficiency and motor performance.

This thesis investigates the feasibility of using Silicon Carbide (SiC)-based multiphase inverters (MPIs) for transportation electrification applications. The research begins with a comprehensive review on the state-of-the-art of MPIs, focusing on voltage source inverters (VSIs) and nine-switch inverters (NSIs), with five-, six-, and nine-phase configurations. The quantitative and qualitative analyses demonstrate that the six-phase VSI is the most promising topology, offering reduced DC-capacitor requirements, lower cabling cost, and higher fault tolerance capability while maintaining the same efficiency and power device count of a three-phase VSI. The feasibility of the SiC-based six-phase inverter is further investigated at the vehicle level, where a vehicle model is developed to study the energy consumption under different drive cycles. The resulting indicate an 8% improvement in vehicle mileage and fuel economy of the SiC-based six-phase inverter compared to its Si-based counterpart. This thesis also examines the current and voltage stresses on the DC-bus capacitor in two-level six-phase VSIs. The study considers two configurations of load/winding spatial distribution: symmetric and asymmetric. Consequently, analytical formulas for the DC-bus capacitor current and voltage ripples are derived. Furthermore, simple capacitor sizing rules in six-phase VSIs with different load configurations are provided. The accuracy of the derived formulas is verified by simulation and experimental testing, and their boundary conditions are identified. Six-phase VSI supplying symmetric loads was found to yield the smallest capacitor size. Based on the foregoing technology review and analyses, a holistic design methodology for a 100 kW SiC-based six-phase traction inverter for an electric vehicle application is presented. The proposed methodology considers the device power level, where discrete SiC MOSFETs are utilized, and the DC-capacitor sizing, where a multi-objective optimization algorithm is proposed to find the most suitable capacitor bank. Mechanical and thermal design constraints are also explored to deliver a compact housing with an integrated coolant channel. The resultant inverter design from the proposed electrical-thermal-mechanical design methodology is prototyped and experimentally tested, demonstrating a 7% reduction in DC-capacitor volume and 21% reduction in cabling cost when compared to conventional three-phase inverters of the same volt-ampere rating. The peak power density of the prototype inverter is 70 kW/L, demonstrating a compact design. Besides, the proposed design is benchmarked against commercial six-phase inverter models, whereby the competitiveness of the proposed design is highlighted. Finally, the unique control aspects of six-phase electric motor drives are investigated to identify suitable controls strategies for various operating conditions. The study places special emphasis on high-speed operation and evaluates several overmodulation techniques. An adaptive flux-weakening control algorithm is also proposed for the six-phase motor drive, which significantly improves the DC-bus voltage utilization of the inverter when used in conjunction with overmodulation. Overall, this thesis provides a comprehensive study of SiC-based six-phase traction inverters and proposes a holistic design methodology that considers electrical, thermal, and mechanical aspects. The results demonstrate the feasibility and advantages of SiC-based six-phase traction inverters for electric vehicle applications. / Thesis / Doctor of Philosophy (PhD) / Electric cars are continuously challenged to meet regulatory mandates that become stricter by the day. This is driven by the need for a clean, reliable, affordable, and sustainable transportation system. In this research, a novel, more reliable, and cost-effective power control unit (PCU) is proposed. The PCU manages the power flow regulation between the battery and the motor(s). The proposed PCU employs the same number of devices as a traditional counterpart, yet in a more modular architecture that doubles the safety factor compared to the standard design. In fault scenarios where the traditional PCU would fail, the proposed PCU would continue operating at half power, allowing the driver and passengers to reach a safe destination before the car is repaired. Extensive analyses were undertaken to identify an optimal design in terms of performance, size, and cost. Then, an engineering prototype is constructed and tested on an electric drivetrain testbed. Finally, the prototype is benchmarked against commercial competitors in the market to establish its economical feasibility.

Visando uma opção de substituição, onde for possível e aplicável, do motor de indução monofásico, este trabalho relata o estudo teórico, a construção, o acionamento e os ensaios de um motor bifásico com ímã permanente no rotor, de baixa potência, utilizando imãs de ferrita na confecção do rotor. / This work shows the theoretical studies, building, driving systems and tests of a small-power double-phase motor with ferrite permanent-magnet in the rotor, based on the original structure of a single-phase induction motor. The objective is to create an option to replace the single-phase induction motor where it is possible and applicable.

Since most of the electrical energy is consumed by the electrical motors, it is necessary to use the electrical energy as efficient as possible. Throughout this study four different types of motors (induction motor, permanent magnet radial flux DC motor, permanent magnet axial flux DC motor, switched reluctance motor) are considered and compared based on their torque per unit volume and speed performance comparison. Torque per unit volume equations are obtained for each of the motor, related to quantities such as magnetic flux density and electric loading and the speed performances are compared by using a washing machine application, which has a wide speed range. As a result of this study torque per unit volume and speed performance of each of these four types of motors are obtained and motors of different types are evaluated due to their torque per motor volume, torque per ampere, efficiency and etc. over a wide speed range to have an idea about the applications of these motors.

This work presents a study of first and second order sliding mode controllers applied to permanent magnet synchronous motor.The aim is a theoretical study and an experimental implementation, using the DSP TMS320F2812 platform, of two second order sliding mode controllers. In addiction a study about the first order sliding mode is presented. The inclusion of this topic aims to provide a comparison elements, related to the performance, precision, robustness, chattering and implementation aspects. In the beginning of this work, are presented the principal concepts related to the approach of the variable structure control. Afterwards, a theoretical study about the first order sliding mode is realized. Beyond the theoretical formulation, the chattering and some techniques for your reduction are presented. Following, two second order sliding mode controllers are presented. The final half of the work presents the application of the sliding mode controllers to the permanent magnet motor. First, the theoretical studies with simulation results are presented. Subsequently, the results in the experimental setup show the viability of the controllers applications. The controllers use the current stator measurements, classical in this kind of application, and the position rotor measurement, obtained by absolute encoder. The tests to the controllers performance analysis consider errors in the system parameters and the load torque such as perturbation input. / Esta dissertação apresenta um estudo sobre a aplicação de controladores baseados na abordagem dos modos deslizantes ao motor síncrono de ímãs permanentes. O objetivo central é o estudo teórico e a implementação em bancada experimental, baseada numa plataforma DSP TMS320F2812, de dois controladores em modos deslizantes de segunda ordem. Entretanto, um estudo sobre o controle em modos deslizantes de primeira ordem também é apresentado. A inclusão deste tópico tem a finalidade de fornecer elementos de comparação no tocante ao desempenho, precisão, robustez, chattering e aspectos relacionados à implementação. Na parte inicial do trabalho, são apresentados os conceitos principais relacionados à abordagem de controle de estrutura variável. Após, um estudo teórico sobre um controlador em modos deslizantes de primeira ordem é feito. Além da formulação teórica, assuntos como chattering e formas clássicas de contornar este inconveniente são abordados. Na seqüência, são apresentados dois controladores baseados no deslizamento de segunda ordem. A metade final do trabalho trata da aplicação dos controladores em modos deslizantes ao motor síncrono de ímãs permanentes. Primeiramente, estudos teóricos com diversos resultados de simulação são apresentados. Posteriormente, resultados obtidos em bancada experimental mostram a viabilidade da aplicação destes controladores ao sistema considerado. Todos os controladores estudados utilizam medidas das correntes de estator, o que é clássico neste tipo de aplicação, e a medida posição do rotor, obtida através de um encoder absoluto. Os testes para análise do desempenho dos controladores levam em consideração erros nos parâmetros do sistema e a carga como uma entrada de perturbação.

Visando uma opção de substituição, onde for possível e aplicável, do motor de indução monofásico, este trabalho relata o estudo teórico, a construção, o acionamento e os ensaios de um motor bifásico com ímã permanente no rotor, de baixa potência, utilizando imãs de ferrita na confecção do rotor. / This work shows the theoretical studies, building, driving systems and tests of a small-power double-phase motor with ferrite permanent-magnet in the rotor, based on the original structure of a single-phase induction motor. The objective is to create an option to replace the single-phase induction motor where it is possible and applicable.