Research on IPMSM Online Parameter Identification with Low Carrier Ratio Considering Nonlinearity of NPC Inverter

Cross-coupling saturation caused by low carrier ratio is critical for interior permanent magnet synchronous machine (IPMSM) control. In order to realize the online parameter identification of IPMSM under low carrier ratio and improve the control performance, this paper proposes a disturbance-based online parameter identification strategy. The high-frequency response signal is obtained by introducing a small current disturbance in the synchronous coordinate system, and the corresponding observer is designed to realize the online parameters identification. In addition, considering the nonlinear characteristics introduced by NPC inverter and the influence of the harmonic current signal under low carrier ratio, the corresponding inverter compensation strategy and resonant controller are designed. Finally, the proposed online parameter identification strategy is verified in simulation.