Multi-Sampling Phase Current Reconstruction and Error Suppression Strategy for AC Electric Drive System

Accurate phase current detection is essential to the control and protection of the AC electric drive system. This paper proposes a multi-sampling phase current reconstruction and error suppression strategy for the DC bus current sampling of AC electric drive system, which aims to mitigate the compound influence of the minimum sampling time and the current sense errors caused by zero-drift on the sampling accuracy. Firstly, by investigation of the relationship between the phase current and the DC bus current, the error detection mechanism of the complementary vector is revealed. Then, a complementary non-zero vector PWM strategy is constructed, and the error suppression is completed through dynamic multi-sampling. Finally, experiments were carried out to verify that the proposed method can reduce the limitations of the minimum sampling time and suppress the zero-drift error by 65%.