Research on current dual closed-loop scheme for PMSM control system utilizing cascaded PI-RC controller

Abstract

In the permanent magnet synchronous motor (PMSM) control system used proportional integral (PI) controller, a large resonance in high-frequency band will be generated through the PI controller. Additionally, high amount alternating current harmonics will be introduced to the PMSM caused by the inverter nonlinearity and other factors, which cannot be eliminated by PI controller. To eliminate the current harmonics in the control system, a novel current dual closed-loop scheme used the PI controller on the current inner loop and the repetitive controller on the current outer loop (cascaded PI-RC controller) is proposed in this paper. First of all, the reference current signal is added to the inner current loop, thus, the satisfied dynamic performance to the control system can be guaranteed. And then, the frequency characteristic and the resonance of the control plant are analysed. Furthermore, in order to suppress the periodic current harmonics for this PMSM, the internal model element and the compensator are studied for the current outer loop controller. Consequently, the stability of the proposed cascaded PI-RC controller is actual by Lyapunov theory. Finally, the effectiveness of the proposed current dual closed-loop scheme is verified by simulation results.

Keywords

• Permanent magnet synchronous motor
• Current harmonics
• Current dual closed-loop
• Cascaded PI-RC controller