Full-Range Non-Linear Adaptive Flux-Weakening Control for IPM and SynRM Drives Including MTPV

Voltage feedback closed-loop control is commonly adopted in Interior Permanent Magnet (IPM) and Synchronous Reluctance (SynRM) motor drives in the flux-weakening (FW) range to comply with inverter voltage limitation. Analysis of voltage control loop transfer function was reported for the first time in [1] [2], demonstrating its non-linear behavior. Adaptive regulation approach was also proposed to allow optimization of regulation dynamics and maximization of DC bus voltage utilization. The linearization methods proposed in [1]–[3] are not suitable for the Maximum-Torque-per-Voltage (MTPV) range. Extension to MTPV range employing a modified flux-weakening model of the analysis methodology was later proposed in [4] but lacking a theoretical analysis of non-linear machines. The theoretical contribution of this paper allows to extend the adaptive control to the full speed range, even in the case of non-linear machines, which was never considered in any previous paper. Faster control and reduced voltage margin are possible, leading to higher torque capability across the whole speed range. Accurate theoretical analysis and simulation results are reported to prove the effectiveness of the proposal.