Effect of Phase Angle Unbalance on Working Characteristics of LSPMSM During Transient Process

Nowadays, line-start permanent magnet synchronous motors (LSPMSM) are being researched as a partial replacement for induction motors for energy-saving purposes. The LSPMSM is typically designed to operate with three-phase voltage balance (VB). Currently, with single-phase loads, the phenomenon of phase angle unbalance (PAU) frequently occurs in the distribution network, which deteriorates the working parameters of the motor and may lead to damage during operation.. Therefore, the content of this paper focuses on studying the impact of PAU in the distribution network on the working characteristics of LSPMSM 15 kW- 3,000 rpm. The analysis results show that when PAU occurs, the LSPMSM has more difficulty starting and may not start. The LSPMSM speed fluctuates strongly, does not work at synchronous speed and mainly works in transient process. During the transient process leads to a higher oscillation torque coefficient k, which explains that the motor will operate with more vibration and acoustics noise. Furthermore, the effect of PAU increases losses, reducing the efficiency and power factor of the motor. The paper evaluates this effect through simulation models and experimental testing in the laboratory for the LSPMSM. The results demonstrate that the theoretical basis synthesized in the paper is suitable for the study.