The actual power capacity of permanent magnet synchronous machine for electric vehicles is usually limited by rotor temperature, and rotor overheating is one of the major reasons for permanent magnet synchronous machine failure. Therefore, an approach of rotor temperature estimation is proposed to improve motor peak power utilization and protect permanent magnet synchronous machine from serious demagnetization due to thermal damage. A real-time iterative algorithm is provided based on the equivalent thermal model for rotor temperature. First, the heat generating principle of each part as well as the power flow transferring of the motor system is analyzed. Second, rotor temperature model is built based on the conservation of energy loss from the stator and real-time superposition of temperature variation rate for the rotor. Finally, the motor performance test bench is built to validate the proposed algorithm and numerical models are also constructed to simplify estimation parameters for rotor temperature model. The algorithm accuracy is improved and verified by optimizing control parameters with given environment temperature and power load. The experimental result shows that the maximum error between actual test value and estimation value is within ±10°C, and it meets the requirement of algorithm accuracy and also benefits on system performance and manufacture cost efficiently.

电动汽车用永磁同步电机的实际功率容量通常受转子温度的限制，转子过热是永磁同步电机故障的主要原因之一。因此，提出了一种转子温度估算方法，以提高电动机的峰值功率利用率，并保护永磁同步电机免受由于热损坏而引起的严重退磁。基于转子温度的等效热模型，提供了一种实时迭代算法。首先，分析各部分的发热原理以及电动机系统的功率传递。其次，基于对定子能量损失的守恒和转子温度变化率的实时叠加，建立了转子温度模型。最后，建立了电动机性能测试台以验证所提出的算法，并建立了数值模型以简化转子温度模型的估计参数。通过在给定的环境温度和功率负载下优化控制参数，可以提高和验证算法的准确性。实验结果表明，实际测试值与估计值之间的最大误差在±10°C以内，既满足算法精度要求，又有利于系统性能和制造成本的提高。