Anisotropy-Based Position Sensorless Control for Safety Functionality Applied to Synchronous Machines in Electric Vehicles

This contribution presents anisotropy-based position sensorless control estimation methods within a modified functional safety concept suitable for rotor position monitoring using a two-level safety concept. The principle includes two position-sensorless algorithms running in parallel, whereby two appropriate modified anisotropy-based algorithms are investigated. The first method, a double high-frequency injection algorithm, is easy to integrate and shows low parameter sensitivity. However, it needs a second injection scheme and subsequent influences the overall system efficiency. In contrast, the second method, an algorithm using the modulation-excitation., does not influence the overall system, but relies on a high bandwidth of the used sensors. Measurements validate that both methods are suitable as monitoring functions in automotive applications.