Browsing by Subject "electrical engineering"

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    Airgap-less Electric Motor
    (2021-08) Alibeik, Maryam; dos Santos, Euzeli; King, Brian; Li, Lingxi; Rovnyak, Steven
    This dissertation focuses mainly on the airgap-less electric machine. An extensive literature review has been presented along with a systematic study that included analytical modeling, simulation with both steady-state and transient analysis, prototype building, and experimental validation. In this type of device, the rotor is allowed to touch the stator at a contact point, which maximizes the internal flux and therefore the electromagnetic torque. A higher torque density motor is proposed in this dissertation due to a reduced reluctance caused by zero airgap situation. A comparison with other high torque density electric machines demonstrates the advantages of the proposed machine. Switched reluctance motor for hybrid vehicle, integrated magnetic gear, induction machines, are some examples of the machines with lower torque density than the airgap-less electric machine. This machine will maximize the generated torque allowing these type of machines to be competitive in applications where hydraulic motors are prevalent, i.e., low-speed and high-torque requirements. Hydraulic motor systems face two major problems with their braking system and with low efficiency due to a large number of energy conversion stages (i.e., motor-pump, hydraulic connections and the hydraulic motor itself). The proposed electric motor, unlike hydraulic motors, converts electrical energy directly to mechanical energy with no extra braking system necessary and with higher efficiency. The evolution of the airgap-less electric machine from three poles to 9 bi-poles is discussed in this dissertation. The modeling of this machine with a minimum number of poles is discussed before a generalization is presented. The simulation and analysis of the airgap-less electric motor has been done using Euler integration method as well as Runge Kutta 4th order integration method due to its higher precision. A proof-of-concept electric machine with nine magnetic bipoles is built to validate the theoretical assumptions.
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    Design and Configuration of a 5 hp Microprocessor Controller Inverter
    (Office of the Vice Chancellor for Research, 2014-04-11) Seck, Ndeye Bitylokho
    The purpose of this project is to design a 5hp variable electric drive that converts an AC input signal to DC then to a variable AC output signal voltage that would vary the speed of an AC induction motor. To achieve the goals of this project, two three phase rectifiers are used to convert the AC input voltage to a DC voltage which in turn is inverted and its output amplitude and frequency varied using a pulse width modulation microcontroller. The inverter consists of six Insulated Gate Bipolar Transistors with gate drivers and a digital signal processor to generate the switching signals. The variation in AC output voltage allows the speed of the AC induction motor to be varied from zero to 1700 rpm. Although the load in this application is a 2 hp induction motor, the power system has been designed for a 5 hp unit. The main advantage of this system is its affordability and energy-efficiency. The cost of all components except that the motor has been estimated to be less than $500, while similar products in the market cost at least ten times more. Low cost and energy efficient variable speed drives have numerous applications including appliances (fans, vacuums, etc.), industrial drives (robotics, centrifugal pumps, etc.) and automotive control (hybrid electric vehicles, electric trains, etc.)