Permanent magnet ac motors have been extensively utilized for adjustable-speed traction motor drives, due to their inherent advantages including higher power density, superior efficiency and reliability, more precise and rapid torque control, larger power factor, longer bearing, and insulation life-time. Without any proportionaland-integral (PI) controllers, this paper introduces novel first-and higher-order field-oriented sliding mode control schemes. Compared with the traditional PI-based vector control techniques, it is shown that the proposed field oriented sliding mode control methods improve the dynamic torque and speed response, and enhance the robustness to parameter variations, modeling uncertainties, and external load perturbations. While both first-and higher-order controllers display excellent performance, computer simulations show that the higher-order field-oriented sliding mode scheme offers better performance by reducing the chattering phenomenon, which is presented in the first-order scheme. The higher-order field-oriented sliding mode controller, based on the hierarchical use of supertwisting algorithm, is then implemented with a Texas Instruments TMS320F28335 DSP hardware platform to prototype the surface-mounted permanent magnet ac motor drive. Last, computer simulation studies demonstrate that the proposed field-oriented sliding mode control approach is able to effectively meet the speed and torque requirements of a heavy-duty electrified vehicle during the EPA urban driving schedule.

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DC-DC converters are an efficient way to convert a source voltage from one to level to another and have found extensive applications in many areas such as portable electronics, solar and wind energy systems. This paper presents a comparison of first order and higher order sliding mode control of buck-boost converters. Sliding mode control is ideal for controlling non-linear systems like switched voltage regulators as a result of its robustness to internal parameter uncertainties and external disturbances. First order sliding mode control is subject to a phenomenon known as chattering, which causes an undesirable oscillation about the desired output. Computer simulation studies are presented and show that the higher order controller reduces this problem.

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Shunt capacitor banks are used on power distribution feeders to reduce losses and regulate the voltage level. The decrease in transmission line current also leads to an increase in the amount of demand that can be supplied without increasing the size of the conductors. In order to maximize the benefit of adding capacitor banks to the distribution feeders, the optimal size and location of the capacitors must be determined. This paper presents a novel optimal control approach to both regulate the voltage drop and reduce the copper loss. A cost function that penalizes both energy losses and voltage drop is developed. The optimal size and location of capacitors can be found using the optimal control solution. Computer simulation results are compared with existing methods of determining the optimal size and location of capacitors. Our approach improves on current methods by providing flexibility to both regulate voltage levels and reduce losses.