Hybrid Sensorless Motor Control in aerospace applications, a survey in sensorless control, optimizing for availability and acoustic noise

A wide range of aerospace applications previously based on hydraulics including the control of aerodynamic surfaces are being actively replaced by lighter, more intelligent Motor Drive Electronics (MDEs). However, motor resolvers commonly used to provide the rotor's position to the MDEs are sensitive devices susceptible to extreme temperature and vibrations, conditions commonly encountered in aerospace applications. This weakness can lead to resolver failures and reduction in system availability. In DALA safety critical motor control designs, system availability is paramount. Following a survey of sensorless methods, this paper proposes a hybrid motor control solution where sensorless rotor position calculation is run in parallel with the resolver interface, monitoring the resolver. In the event of a resolver failure, the sensorless motor control takes over controlling the motor. Furthermore in order to suppress acoustic noise produced from High Frequency injection, a variant of the Pseudo Random High Frequency injection method is also proposed.