UC Santa Cruz

This dissertation explores the feasibility of utilizing Silicon Carbide (SiC)Electroluminescence (EL) to estimate current from a SiC MOSFET’s body diode in classical power converter feedback control systems. The study delves into the current and temperature dependencies of SiC EL, demonstrating how light intensity at key wavelengths (390 nm and 500 nm) varies with current and temperature. By maintaining a constant junction temperature, the circuit’s electroluminescence is directly affected by a change in current, while a rise in junction temperature influences the light emission at different wavelengths. The work presents an experimental setup that integrates SiC EL with a closed-loop control system to regulate current in a buck converter. Results from the system demonstrate that SiC EL can be used to predict current, providing a basis for future motor drive torque regulation, speed control, and voltage control in power converters. The dissertation also addresses the challenges of low light intensity and nonlinearity in SiC EL measurements, proposing methods to optimize sensitivity and accuracy using avalanche photodetectors and calibration techniques. Despite limitations, such as the weak emission of SiC EL compared to direct bandgap materials, the research establishes a novel and effective approach for current estimation in power electronics applications, paving the way for improved control systems in power conversion and motor drives.