Abstract: Based on engineering practice, the influences of welding groove size, shape, position, and quantity on the three-phase induced potential imbalance of permanent magnet synchronous motors for 6-pole 54 groove new energy vehicles were firstly simulated and analyzed in this paper. And secondly, the variation law of the three-phase induced potential imbalance of the motor was simulated and analyzed under different stator slot numbers and motor pole numbers. Finally, prototype production and testing verification were carried out. Through simulation analysis and experimental verification, it is pointed out that for permanent magnet synchronous motors used in 6-pole 54 slot new energy vehicles, the width and depth of the welding groove will affect the imbalance of the three-phase induced potential of the motor. The imbalance of the three-phase induced potential of the motor is directly proportional to the size of the welding groove. At the same time, it was pointed out that for permanent magnet synchronous motors, from the perspective of reducing the imbalance of three-phase induced potential, the number of stator welding slots should not be an integer multiple of the number of poles. In addition, the corresponding relationship between the balance of three-phase voltage and current of the motor and the torque output and operating efficiency of the motor was also pointed out.

Key words: permanent magnet synchronous motors, stator core, weld joint