Axial Position Estimation of Conical Shaped Motors for Aerospace Traction Applications

Abstract

-This paper is concerned with the use of conical induction machines. Such machines are extremely valuable when apart from the rotational torque output, an axial translation of the rotor is also required. The inherent attraction between the stator and rotor of any machine, combined with the geometry of a conical machine will provide the required axial movement. However, when applied to aerospace applications, where reliability is very important, then full monitoring of the axial position is required. In this paper, an innovative approach aimed at monitoring and controlling the axial translation of a conical induction machine is proposed and investigated. In order to increase the system reliability and also decrease component count, as demanded by the application, the methodology is a sensor-less technique, based on an innovative variant of the highfrequency injection approach. In this paper, the technique has been fully investigated and experimentally validated on a purposely-built, instrumented test-rig.Index Terms--conical motor; sliding rotor; high voltage signal injection; in-wheel actuator.

A two-degrees-of-freedom system for wheel traction applications

“…As mentioned above, this is dependent and proportional to the level of magnetizing current and the motor saliency. The monitoring procedure, in fact, is based on a self-sensing technique [41,42] that requires the injection of a highfrequency voltage signal and then tracks changes in the machine parameters in order to relate them to the rotor axial position. A perceived advantage of this 'sensor-less' technique is, of course, the lack of dependency on linear position sensors, which could be detrimental in terms of component count and system reliability.…”

“…7, the high-frequency voltage is generated and added to the main voltage in αβ reference frame, thus it represents a rotating vector. As demonstrated in [41,42], the changes in motor saliency cause the variation of the amplitude of the negative sequence signal of the high-frequency current response (In) to the injection signal. The values of In have been recorded for different levels of magnetizing current (Id) and different axial positions.…”

A Position Sensorless Control of an Axial Flux-Switching Permanent-Magnet Motor Based on High-Frequency Pulsating Voltage Vector Injection

“…A high-performance transmission system needs to install a position sensor to measure the real-time rotor position, but at the same time, the speed control system has high cost, large size, and low reliability, which limits its application range. In order to overcome the defects caused by mechanical position sensors, scholars have carried out a lot of research on the position sensorless technologies of AC motors [5][6][7][8][9][10][11][12][13][14][15][16]. Sensorless technology reduces the size and cost of the motor, and improves the reliability of the system.…”

“…Sensorless technology reduces the size and cost of the motor, and improves the reliability of the system. These technologies can be divided into two categories, namely based on the back EMF [5][6][7] and the based on salient pole effect [8][9][10][11][12][13][14][15]. The method based on the back EMF has superior performance at medium and high speeds, but since the magnitude of the back EMF is proportional to the rotation speed, it is not suitable for zero-speed and low-speed operation.…”