TECHNOLOGY AREA(S): Air Platform OBJECTIVE: Develop direct optically controlled, 1,200 to 2,000 V, 10 to 120 A, wide bandgap power switching device for applications in electro-hydrostatic (EHA) and electro-mechanical (EMA) actuator motor drives for air platforms. DESCRIPTION: Due to the inherent immunity of photonic technology to dynamic electromagnetic events, its application to power electronics used to drive flight-critical EHA and EMA surface control actuators is predicted to increase the reliability and survivability of these subsystems dramatically. Wide bandgap (WBG) power device technology has been under development for several years, targeting applications in DoD power communication systems requiring high-reliability and harsh-environment operability. Wide bandgap materials quantified power device performance benefits, in addition to its high temperature capability, include; improved component efficiency through reduced on-state and switching losses, lower on-resistance for high voltage devices, and higher frequency switching capability. As such, wide bandgap semiconductors are an emerging high reliability power device technology slated for utilization in several DoD platforms. Conventionally, passive and active filtering is used to reduce drive control susceptibility to large voltage and current switching transients and for suppression of parasitic oscillations inherent to electronic motor drive systems. However, these filters are incapable of protecting either the signal-level control electronics or the power devices themselves from catastrophic failure when exposed from external events and account for a significant volume and weight of the EHA/EMA electronics system. Optically-gated power semiconductors can minimize or eliminate the noise susceptibility of conventional power drive electronics. A successfully developed and fielded optically controlled EHA or EMA flight surface control subsystem could dramatically increase the survivability of air and other DoD platforms. An additional benefit is the possibility of reducing the volume and weight associated with conventional filters used to protect low-voltage control devices from the inherent radiated EMI associated with switching large voltages and currents. Lightweight, rugged, and compact optical sources that satisfy the requirements of repetition rate, optical power, and wavelength are required for direct device triggering. High device gain translates directly to reduced optical triggering power requirements thereby reducing the cost and operational complexity of the optical source. Therefore, considerations pertaining to the optical source and driving mechanism significantly impact the suitability of an optical power switch to satisfy the power system architecture specifications in a given platform. In order to make overall system efficiency comparable to state-of-the-art electrically controlled WBG power electronics, it is desired that a 1200 V switch requires less than 2 W of optical power per amp of continuous current. Research is also likely needed to develop an appropriate opto-electrical packaging scheme that reduces the triggering power loss and that can handle harsh environmental conditions. In summary, this topic is intended to investigate the area of optical control of wide bandgap power devices as it relates to power utilization and control technology that will satisfy stringent environmental requirements. The objective is to identify and address specific technology limitations and pursue solutions based on sound physical principles, which can lead to the development of robust, optically controlled power technology that can be utilized in EHA/EMA motor drives and other electrical power applications on DoD platforms. PHASE I: Demonstrate the feasibility of new and innovative wide bandgap direct optical switching power devices. The development of a fundamental switch structure design, with the fabrication and characterization of a scaled prototype, is highly desirable. The device should block at least 1000 V and conduct greater than 10 A of current. The temperature capability of the device should support operating at 150 degrees C. PHASE II: Develop and optimize full-scale, prototype, optically triggered wide band gap switches. Perform detailed static and dynamic electrical and optical characterizations of switch performance. Develop package design for optical integration and high power handling. Successfully integrate the prototypes into a representative power electronic component (converter, inverter, motor drive, etc.) for an equipment-level demonstration of the desired functionality using only optical control signals. PHASE III: Military application: This technology could lead to insertion in a variety of military applications. Potential aviation applications include directed energy weapons, motor drives, power converter, power inverters, and other representative power electronic components. REFERENCES: 1. T. L. Weaver and R. H. Smith, Photonic Vehicle Management, 20th Digital Avionics System Conference, Daytona Beach, FL, October 2001.; 2. D. J. Halski, Fly-by-light Flight Control Systems, McDonnell Douglas Aerospace, Proc. SPIE, Fly-by-Light: Technology Transfer, Vol. 2467, p. 34-45, 1995.; 3. S. K. Mazumder and T. Sarkar, Optically-triggered Power Transistor (OTPT) for Fly-by-light (FBL)/EMI Susceptible Power Electronics, IEEE Power Electronics Specialists Conference, pp. 1-8, 2006.; 4. J. S. Sullivan, Wide Bandgap Extrinsic Photoconductive Switches, Lawrence Livermore National Laboratory Report LL LLNL-TH-523591, January 20, 2012.KEYWORDS: Fly-by-light, Power-by-wire, Photonics, Power Electronics, Wide Bandgap Device, Optical Isolation, Gallium Nitride Semiconductors, Electrical Actuators, High Electric Field Protection, EMI
