A new approach to feedback linearizing control of variable reluctance motors for direct-drive applications

In this paper, we consider feedback-linearizing control of VR (variable reluctance) motors which have been increasingly used in high performance direct-drive applications. We characterize all torque controllers that can make the generated torque of a VR motor linear to torque command but without torque ripple. The torque controllers maximize the range of torque commands which are admissible under the physical limitation in stator currents. The whole class of all such torque controllers is parameterized in the explicit form which contains a function to be chosen freely. This free function can be used to achieve other control objectives as well as linear dynamic characteristics. As the example for optimal choice of the free function, we actually determine an optimal free function for minimal rate of change in current commands. To illuminate further the practical use of our torque controllers, we present some experimental results for the case of a commercially available VR motor