Optically Activated Gate Control for Power Electronics

This paper outlines and demonstrates a novel optically activated gate control (OAGC) mechanism that can dynamically affect power-converter switching loss, dv/dt and di/dt stresses, and electromagnetic emission at the device level by controlling the switching dynamics of the power semiconductor device (PSD) via modulation of its excitation current using a GaAs-based optically triggered power transistor (OTPT). Further, due to conductivity modulation of the OTPT using direct photogeneration, the switching initiation delay using the OTPT-based OAGC approach is almost negligible, as compared to prevalent fiber-optics-based techniques for power electronics. Starting with a description of the basic mechanism of the OAGC and how it differs from other active-gate-control-based approaches, this paper outlines the implementation of the OAGC (including the design of the GaAs-based OTPT) and the mechanism for controlling the PSD turn-on an turn- off dynamics by varying the optical intensity of the OTPT. Subsequently, the fundamental parameter, linking the control of the OTPT and its impact on the performance parameters of the power converter, is identified and the correlation is experimentally demonstrated. Finally, to address the mutually opposing dependence of switching loss, and dv/ dt and di/ dt stresses on the optical intensity of the OTPT, a joint optimization mechanism is outlined and its outcome is experimentally demonstrated.