An FTSMO-Based Current Measurement Offset Error Compensation Method in SPMSM Drives

Precise current measurement is significant for the vector control of permanent magnet synchronous motor (PMSM) with high quality. However, the current measurement offset error will inevitably occur due to thermal drift, residual current, nonlinearity and other factors, and thus causes undesirable fluctuation in speed and torque, degrading motor control performance. To address this issue, this article proposed a fast terminal sliding-mode observer (FTSMO)-based method for current measurement offset error estimation and compensation in PMSM drives. First, the finite-time convergence of the state variable and its derivative are guaranteed by ingeniously establishing a fast terminal sliding surface. Second, the chattering phenomenon is well avoided by designing a proper sliding mode control. Therefore, the proposed method is capable to realize accurate offset error compensation with fast dynamics. Finally, the effectiveness of the proposed method is validated by experimental results on a 1.0 kW SPMSM drive platform, which shows that current measurement offset error is compensated with excellent performance, and torque pulsation and speed ripple are effectively suppressed.