On-line estimation and compensation scheme for dead time and inverter nonlinearity independent of parameter variations in PMSM drive

A new on-line compensation scheme that can exactly estimate the dead time and inverter nonlinearity even under the parameter variations is proposed for a PWM inverter-fed permanent magnet synchronous motor drive. The proposed scheme is based on the fact that the sixth-order harmonic component in total disturbance estimated under the presence of various uncertainties is mainly caused by the dead time and inverter nonlinearity. The total disturbance due to the parameter variations as well as the dead time and inverter nonlinearity is estimated by the adaptive scheme. From this total disturbance, the sixth-order harmonic component is extracted through the harmonic analysis. The obtained sixth-order harmonic is processed by the PI controller to estimate the disturbance only caused by the dead time and inverter nonlinearity in the stationary reference frame. The effectiveness of the proposed scheme is verified through the comparative simulations and experiments using DSP TMS320F28335. Without requiring an additional hardware, the proposed scheme can effectively compensate the dead time and inverter nonlinearity even under the parameter variations.