Improved Identification of High Frequency Parameters for Self-Sensing Control of PMSM Using Test Current Signal Injection

A stable anisotropy-based self-sensing control of PMSM at standstill and low speeds is only possible if the investigated machine shows a minimal difference between the differential d-axis and q-axis inductances. To check if a machine fulfills this requirement over the whole operating range, a measurement of these differential inductances is needed. For a further improvement of the accuracy of the self-sensing control, the differential mutual inductances also must be known. Therefore an extended control scheme is used to inject an additional high frequency test current with zero steady-state control error. In this case the controller output signals can be used to calculate the high frequency machine parameters directly. Previous publications suggest to block the rotor of the investigated machine in fixed positions and to measure the parameters for all needed current operating points and rotor positions. In this paper a novel extension of the high frequency current controller is presented, which allows to identify the high frequency machine parameters while the tested machine is rotating. With this new approach the time needed for parameter identification can be reduced enormously.