Precise Cumulative Error Calibration With Delay Effects Rejected for Incremental Encoders Used in High-Speed PMSMs

In this letter, we propose a novel cumulative error calibration method for the incremental encoders used in permanent magnet synchronous motors (PMSM) based on precise position estimation and counter value error (CVE) compensation. First, a sliding-mode observer (SMO) with analog delay compensated is innovatively developed to estimate the precise rotor position. The novel analog delay compensation method is achieved based on two sequential procedures: phase delay computation and current compensation. Then, relying on the errors between the accurate position estimated by the SMO and the measured one, the CVE can be calculated to correct the output of the counter. Finally, the experiment is conducted on a three-phase 1.5 kW PMSM to validate the proposed cumulative error calibration strategy.