Overall Electrical Parameters Identification for IPMSMs Using Current Derivative to Avoid Rank Deficiency

An approach to identify overall electrical parameters for interior permanent magnet synchronous motors (IPMSMs) in steady state is proposed in this article using current derivative, with which the concerns of rank deficiency can be avoided. It is found that the conventional IPMSM models under d-q frame always neglected the pulsewidth modulation (PWM) switching effect of inverter and the quantities in these models are always regarded as constant values in steady state, making it untoward to identify all motor parameters simultaneously. Instead, the switching IPMSM model is built to analyze the details of PWM, and full-rank current derivative functions during zero and active voltage vectors are given, respectively. Without any injected signals, all electrical parameters including dq-axis inductance, stator resistance, and permanent magnet flux linkage are able to be figured out in steady state by measuring the phase current derivatives. Simulations and experiments are implemented to validate the proposed approach.