SBIR-STTR Award

We propose to develop a SiC inverter for controlling a three-phase AC induction motor of at least 6 HP. In Phase I, we shall concentrate on (i) building a Si-based inverter with DSP for real time control by using high speed Si devices for over 30 KHz operation, (ii) building a hybrid SiC-diode/Si-IGBT based inverter and evaluating its performance, (iii) preliminary design of a SiC-based inverter, (iv) survey of state-fo-the-art in SiC device development and identifying the type of SiC devices for Phase II SiC inverter development, and (v) drafting a test plan for the SiC inverter. In Phase I, inverter characterization will be concentrated on switching losses vs. temperature, inverter efficiency at different temperatures, and the highest possible operating frequency and temperature. We shall also, in Phase I, characterize state-of-the-art SiC diode as well as its performance in the hybrid inverter circuit. In Phase II, SiC devices will be procured to build SiC inverters for motor control up to at least 6 HP. Improved SiC inverter design will be identified and used to guide the commercial development in Phase III. High performance SiC inverters for motor control in Army vehicles such as HMMWV and for commercial hybrid and all electric vehicles as well as for numerous commercial power electronic systems.

We propose to carry out an intensive program focusing on the research and development of a high performance SiC inverter for motor drive. We shall design and develop high temperature packages for SiC devices and appropriate thermal management for the inverter to allow the inverter to operate at high device junction temperatures and high PWM frequencies. A detailed survey on the available SiC power devices suitable for inverter applications will be conducted and procured devices will be evaluated to confirm their ratings and suitability for planned investigation. Equivalent circuit models for SiC diodes and switches will be developed for inverter simulations. We shall determine the full operating range of temperature, frequency, and inverter efficiency for the SiC inverter. We shall also determine the switching loss, motor efficiency, speed and torque. Based on an analysis of the experimental results and SiC inverter modeling, we shall estimate the projected benefits of SiC-based power inverters for military and civilian hybrid vehicle applications. The Phase II SiC inverter R&D work will provide the key to the commercialization development of a high power SiC-based motor controller in Phase-III for 70 HP operations at 60 kHz.

Keywords:
high-frequency inverter, high temperature packaging, SIC inverter, SIC rectifiers, SIC switches, motor control, compact inverter, high-temperature