Current Control of Interior Permanent Magnet Synchronous Motor with Flux-linkage Model Considering Digital Control Delay Effect

The design objective of high power density, coupled with the motor's high speed and heavy overload operation, necessitates a comprehensive consideration of magnetic saturation factors in the modelling and control method of interior permanent magnet synchronous motors. In this paper, current dynamics and current controller design methods are analysed based on the nonlinear flux-linkage model. The effect of digital control delay on the stability of current loop control at high speeds is analysed further, and the current controller is improved by introducing a feed-forward active damping term. The simulation results show that the proposed current control method improves the current response performances at high overload conditions in comparison to the current control method based on the linear model. The unstable poles caused by the digital control delay are eliminated by the voltage compensation of the active damping term at high speeds, which improves the stability of the control system.