Nonlinear Damping Compensator for Dead-Time Disturbance Voltage Considering Parameter Uncertainty in SPMSM Drives

A dynamic model of surface-mounted permanent magnet synchronous motors (SPMSMs) is constructed to include the dead-time disturbance voltage of the voltage-source inverter and SPMSM parameter uncertainty. The constructed model reveals that both the disturbance voltage and the parameter uncertainty degrade the SPMSM stator current control performance. Based on this notion, a nonlinear damping compensator is designed to simultaneously compensate for the dead-time disturbance voltage and parameter uncertainty in a unified structure. The designed compensator is advantageous because it is implemented with only the static feedback of available system variables with a low computational load, which enables the compensation signal to be calculated within one sampling period without requiring a specific calculation cycle. A rigorous analysis using a Lyapunov function shows that the designed compensator achieves the global exponential ultimate boundedness of the stator current errors with arbitrarily small bounds and fast decay rates in the presence of both the dead-time disturbance voltage and parameter uncertainty. The designed compensator performance is demonstrated by performing experiments using a 750-W laboratory SPMSM drive and comparing the experimental results with those of a conventional proportional-integral controller with a feedforward compensator.