Research on a Dead-Time-Compensated DC-Link Current Estimation Algorithm for PMSM

The DC-link current in PMSM drive systems is a critical variable for indicating DC-side power level and enabling efficiency optimization. However, existing sensorless current estimation methods are significantly affected by dead-time effects, resulting in limited estimation accuracy. To address this issue, a quantitative analysis of the impact of dead time on three-phase current reconstruction is conducted, and a mathematical model describing the relationship between estimation error and key influencing factors is established. Based on this, a unified framework integrating dead-time voltage compensation with DC-link current estimation is proposed. By real-time identification of stator current polarity, the dead-time-induced voltage error is accurately calculated, and a feedforward voltage compensation is implemented in the αβ stationary reference frame to effectively mitigate voltage deviation and waveform distortion. The reference voltage is subsequently incorporated into the DC-link current reconstruction process, enabling high-accuracy current estimation. The effectiveness of the proposed method is validated through both simulation and prototype experiments, demonstrating that the algorithm can accurately estimate the DC-link current of PMSM drive systems under various operating conditions, with an estimation error of approximately ±2%.