This article proposes improved mathematical models for torque and system efficiency used toward obtaining accurate current advance angle for maximizing the efficiency of an interior permanent magnet (IPM) synchronous motor. First, improved torque and efficiency calculation procedure that consider the effects of parameter variations, such as inductance, stator resistance and PM flux linkage simultaneously, and motor and inverter losses, have been developed from a combination of analytical models and practical experiments. Subsequently, an offline search procedure has been utilized to determine the optimal current angle using the improved dq-axis-based models. The novelty of the efficiency model is that the method uses preliminary noninvasive experimental tests to consider the saturation and temperature effects simultaneously and successfully determine the relationship between stator and rotor temperatures by using only controller command voltages and currents. Experimental investigations are performed on a laboratory IPM for validating the developed control method through interpolation of improved look-up tables with the derived current angle values for varying speed, torque, and temperature conditions. The effectiveness of the proposed method in improving efficiency is also verified and compared with maximum efficiency and maximum torque per ampere methods using experimental sweep tests.

中文翻译：

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非侵入性和改进的转矩和效率计算对 PMSM 最大效率控制的电流提前角确定

本文提出了改进的转矩和系统效率数学模型，用于获得准确的电流提前角，从而最大限度地提高内置永磁 (IPM) 同步电机的效率。首先，结合分析模型和实际实验，开发了改进的转矩和效率计算程序，该程序同时考虑了参数变化的影响，例如电感、定子电阻和 PM 磁链以及电机和逆变器损耗。随后，使用改进的基于 dq 轴的模型，利用离线搜索程序来确定最佳当前角度。效率模型的新颖之处在于，该方法使用初步的无创实验测试，同时考虑饱和度和温度影响，仅使用控制器命令电压和电流就成功地确定了定子和转子温度之间的关系。实验研究是在实验室 IPM 上进行的，以通过对改进的查找表进行插值来验证开发的控制方法，该表具有针对不同速度、扭矩和温度条件的导出电流角度值。还验证了所提出的方法在提高效率方面的有效性，并使用实验扫描测试与最大效率和最大每安培扭矩方法进行了比较。实验研究是在实验室 IPM 上进行的，以通过对改进的查找表进行插值来验证开发的控制方法，该表具有针对不同速度、扭矩和温度条件的导出电流角度值。还验证了所提出的方法在提高效率方面的有效性，并使用实验扫描测试与最大效率和最大每安培扭矩方法进行了比较。实验研究是在实验室 IPM 上进行的，以通过对改进的查找表进行插值来验证开发的控制方法，该表具有针对不同速度、扭矩和温度条件的导出电流角度值。还验证了所提出的方法在提高效率方面的有效性，并使用实验扫描测试与最大效率和最大每安培扭矩方法进行了比较。