A Parameter Adjustable Flux Weakening Strategy for IPMSM Drive Without Electrolytic Capacitor

Interior permanent magnet synchronous motor (IPMSM) drives without electrolytic capacitors have many advantages, including the elimination of the need for power factor correction (PFC) circuits, enhanced reliability, and reduced cost. However, due to the fluctuation in DC link voltage, the DC link voltage utilization and the highly increased peak value of stator current caused by fluctuation are major issues in the flux weakening region. Therefore, it is necessary to design the flux weakening strategy to solve these two problems comprehensively. In this paper, a voltage difference flux weakening strategy with adaptive parameters is proposed. By defining a cost function focused on voltage utilization efficiency, the DC link voltage can be utilized maximally with the voltage difference between the reference and the real value. Moreover, the parameters of the proposed method can be changed adaptively based on the speed change, so that the fluctuation in stator current can be suppressed, and the peak value of stator current can be reduced effectively. The frequency spectrum of the grid current shows that the harmonics meet the regulation of IEC 61000‐3‐12 R sce ‐33, and the overall power factor is above 98.5% without any additional circuit. In order to verify the effectiveness of the proposed method, hardware‐in‐the‐loop (HIL) experiments are carried out. The experimental results show that the proposed flux weakening strategy can utilize the DC link voltage and reduce the peak value of stator current effectively.