Optical intensity modulated gate control of power-electronic system performance parameters

In a power-electronics system (PES), switching dynamics of the power semiconductor devices (PSDs) may strongly influence some key system-level performance parameters - specifically, power-conversion efficiency, electromagnetic noise emission, and dv/dt and di/dt related PSD stress. Aim of the this Dissertation research is to achieve PSD switching-dynamics modulation along with optical isolation in a unified scheme, which enhances immunity to external electromagnetic noise and provides galvanic isolation between the high-power, high-voltage power stage and the low-voltage control electronics, in addition to achieving dynamic control of the system-level performance parameters.;Fundamentally, slowing down the switching transition speed of the PSD by modulating the optical-intensity would reduce the electromagnetic noise by reducing the rate of change of voltage and current but it may also lead to an increment of switching loss and degrade the power-conversion efficiency. Principal research challenges in this Dissertation are, therefore, determination of the optical-intensity level, which yields an optimal balance among efficiency and PSD stress and synthesis of a mechanism for experimental validation.;A GaAs-based optical-triggering device is designed and fabricated for realizing switching dynamics modulation using light. Modeling and characterization of the dynamics of the optical-triggering device is done. Various types of PSD are coupled with the optical-triggering device and modulation in their switching parameters with variation in optical intensity is analyzed and experimentally characterized. Finally, some key power-electronic system performance parameters such as power-conversion efficiency, PSD dv/dt and di/dt stress, and electromagnetic noise emission are experimentally shown to be modulated by optical intensity variation using such optically-controlled PSD in a prototype power converter. An optimal optical-intensity level is also experimentally determined which yields a balanced trade-off between mutually opposing trends of power-conversion efficiency improvement and PSD stress mitigation.