Browsing by Author "Kouzani, Abbas Z."

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    An Improved Switching Control Technique for Single-Phase Voltage Source Inverter
    (IEEE, 2020-10) Chowdhury, Md. Razon; Chowdhury, Sumon; Islam, Md. Rabiul; Mahfuz-Ur Razman, A. M.; Kouzani, Abbas Z.; Mahmud, M A Parvez
    The traditional pulse width modulation techniques cause high power loss in the power devices of the inverter. This paper presents a modified equal loading bus clamping pulse width modulation technique, where the modulating voltage is clamped to its dc bus voltage for 120 degree in each half cycle of the fundamental period. Consequently, the switching loss of the inverter is greatly reduced, which in turn increases the inverter overall efficiency and active life time. Also, the total harmonic distortion of the converter is also improved. Furthermore, the dc bus voltage utilization is around 81.6%. The improved performance of the proposed technique is validated by simulation in MATLAB/Simulink.
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    Model Predictive Control Based Advanced Switching Strategy for H-bridge Converter Used in SMES Applications to Obtain Even Loss Sharing
    (IEEE Transactions on Applied Superconductivity, IEEE, 2021-07-02) Chowdhury, Md. Razon; Chowdhury, Sumon; Rahman, Md. Ashib; Islam, Md. Rabiul; Mahmud, M. A. Parvez; Kouzani, Abbas Z.
    The power converters are mostly prone to frequent failures. One of the major causes for their failures is uneven distribution of power losses among the semiconductor devices. The conventional equal loading bus clamping pulse width modulation scheme guarantees equal loss sharing among the devices when the converter operates at unity power factor (PF). However, when the converter operates at non-unity PF, some of the devices are heavily stressed due to higher loss density, i.e., junction temperatures of some of the devices become higher than the others. This paper proposes four switching sequences based on model predictive control for a grid-connected single-phase H-bridge converter used in various applications including superconducting magnetic energy storage system. In each sector, two switching sequences having different zero vectors are selected alternately. The proposed strategy can achieve balanced loss sharing and almost uniform thermal stress among the devices of the converter under all pf. The novelty of the proposed technique is verified with a scaled-down laboratory test prototype.