High reliability motor control for aerospace applications

Weight penalties imposed on commercial and military systems uniquely challenge motion system designers to adhere to compact design rules without compromising robustness and product reliability. Platforms are converting from hydraulic and pneumatic power to electric drives to give system integrators the opportunity to integrate performance and diagnostic monitoring with high speed control algorithms using advanced control ICs. But opportunity comes with a cost, forcing the electrical designer to confront the difficult challenge of creating a design that is not only physically small and functionally demanding but also capable of working in an environment of high speed digital control ICs integrated tightly with high voltage/high current semiconductor switches. This paper addresses the use of a new Sensorless Control Topology called iMotion to implement entire motor control functionality in a small footprint suitable for use in aerospace. A digital control ASIC includes a robust sensorless Field Oriented Controller having all required functions including Built-in Test (BIT) and protection features for highly reliable control of a sine wave commutated PMAC motor. Two critical technologies, hardware based advanced control and use of HVIC components, have enabled designers to achieve the high level of performance required in fast control loops while operating within a high noise environment (dv/dt & di/dt). The co-location of iMotion ASIC controller, gate drivers, and feedback electronics into a very small package is discussed in this paper. Embedded hardware protection, diagnostic and monitoring functions are also dealt with. Test data highlight the important steady state performance characteristics and startup sequencing.