Separate fractional-order PI controller of current loop based on Sigma-delta ADC

This paper proposes a novel control method aimed at enhancing the current loop performance of permanent magnet synchronous motor (PMSM). The method leverages Sigma-delta ADC (SD-ADC) for current sampling and a SINC digital filter for filtering and demodulation, thereby facilitating the acquisition of feedback current with improved accuracy and noise immunity. In the context of the original PI control scheme, a two-loop fractional-order PI (FOPI) controller is implemented for current loop control. Moreover, each feedback loop utilizes a SINC filter with a varying oversampling ratio (OSR), leading to superior dynamic performance when compared to conventional PI controllers. The efficacy of the proposed control method is thoroughly validated through comprehensive simulation analysis and results.