An Accurate Inverter Nonlinearity Compensation Method for IPMSM Torque Estimation Based on Numerical Fitting

The accurate compensation of inverter nonlinear voltages error (INVE) is of great significance in improving interior permanent magnet synchronous motor (IPMSM) field-oriented control system performance. In this article, the modeling and compensation of INVE are studied. First, the effect of parasitic capacitance between collector and emitter on INVE is divided into three cases, and specific mathematical models are given for different cases. Combining the INVE caused by the dead time, the turn-on and turn-off delay time of the switching device, and the voltage drop of the switching device and diode, an accurate INVE model is established. Second, to address the problem that it is difficult to deal with the relationship between $D(i_{X})$ and $D(i_{X}$ /2) in the INVE acquisition method based on self-commissioning, an accurate INVE acquisition method based on modeling and numerical fitting is proposed to realize the compensation of INVE. On this basis, torque estimation accuracy in steady-state operation is proposed as the criterion to judge the merits of INVE compensation. Finally, experiments verify the effectiveness and superiority of the proposed method.