Resolver-to-Digital Conversion Based on Enhanced Single Degree-of-Freedom ADRC for Acceleration Position Error Suppression in PMSM Drives

The software-based resolver-to-digital conversion (RDC) systems, applied for acquiring accurate rotor position, are widely used in the permanent magnet synchronous motor (PMSM) drive system. However, when the PMSM speed changes, there is an acceleration rotor position error. This position error inevitably weakens the PMSM control performance in applications. To deal with this problem, this article proposes an enhanced single degree-of-freedom active disturbance rejection controller (SDOF-ADRC) for the RDC system to suppress the acceleration position error caused by PMSM speed change. In the proposed scheme, another error-based extended state observer (ESO) is added to the SDOF-ADRC, which is connected in series with the original error-based ESO to form a cascaded second-order observer. The original observer is applied to suppress the total disturbance in the system, while the added observer is a supplement to the original observer. It can suppress the remaining disturbances in the RDC system that cannot be suppressed by the original observer. Finally, the experimental results show that, compared with the proportional-integral (PI) controller and the traditional SDOF-ADRC, the proposed enhanced SDOF-ADRC can effectively suppress the acceleration position error caused by PMSM speed change.