考虑谐波的异步电机在线能效计量检测理论与方法研究

Efficiency determination methods of induction motor based on high-precision model and efficiency measurement methods with high accuracy are key issues to upgrade motor efficiency level in our country. To overcome the shortcomings in existing converter-fed induction motor efficiency measuring and testing methods, this project is devoted to improve the measuring and determining precision from three new perspectives, namely, establishing high-precision induction motor model considering harmonics, tracing experimental uncertainties, researching new detecting methods. Firstly, a high-precision theoretical model will be established, and the quantitative studies of the impacts of harmonics and negative sequence components on motor efficiency will be obtained and verified by simulation. Using the characteristic that harmonic(s) and negative sequence component(s) can be superimposed upon an electrical parameter, a new testing method for measuring the quantitative impacts of the harmonics on losses and efficiency are proposed. Secondly, for the in-service motor efficiency test featuring with great uncertainty, the grading of uncertainty assessment will studied. Thirdly, for the measurement with low uncertainty grading, a new measuring method based the voltage-current difference, which brings about a small scale, is proposed to increase the measuring precision. Finally, the proposed model and methods are improved and optimized through experiments and simulation. In a conclusion, this research project can provide scientific methods and techniques support for efficiency evaluation of induction motor, therefore it is very meaningful for promoting exploitation and popularization of high efficient motors and speeding up the upgrading process.

考虑谐波的异步电机能效高精度检测方法和基于模型的能效计量方法的研究是提高我国电机能效水平的关键问题之一。本项目针对目前变频器驱动的异步电机能效计量检测方法的不足，考虑谐波进行理论研究，并从考虑滤波器的不确定度等级评定及改进检测方法的新角度研究高效电机能效计量检测方法。首先，考虑谐波建立高精度理论模型，定量研究谐波对电机能效的影响。利用电气系统电参量可叠加谐波、基波负序分量特点，提出一种定量检测谐波对损耗和能效影响的试验方法。其次，针对电机在线能效检测具有较大不确定性的特点，研究异步电机能效检测的不确定度评估。再次，针对测量不确定度低的问题提出一种新的基于被测电机电压-电流差值的能效计量检测方法。最后，结合运行试验和虚拟样机仿真研究，改进和优化提出的模型和计量检测方法。该项目的研究将为电机能效评估提供科学方法和技术基础，对推动我国高效电机开发推广、促进电机产业升级有重要意义。

目前，我国电机系统运行效率较国外仍有较大差距。从企业角度分析，管理制度不完善，对电机运行管理比较粗放，电机系统节能意识淡薄。同时，企业把重点放在可带来直接经济效益的产品上，而忽略企业运行中最大耗电量的电机，造成高能耗，运行效率较低的状况。因此，对电机的能效计量检测技术进行研究，有助于减少电机能耗，节约成本。.本项目以现有工业电机YB710S1-10为例，研究了考虑谐波时的数学模型，考虑不同谐波含量时的能效情况进行研究，采用时步有限元软件对其仿真，针对几种工况在专用能效测量平台进行能效测量，并对其在线测量的不确定度进行了研究，进一步提出了新的差动能效计量方法。.本项目通过仿真和实验验证了谐波对异步电动机效率的影响。首先，研究了不同阶次谐波下的效率特性。计算得出了效率随输入电压的变化而变化的特性，当电压为8.5kV时效率达到最大值。此外，还计算了效率与负载率的关系。结果表明，效率随负载率的变化而变化，在50%时达到最大值。其次，在不同谐波水平下，对铁损、铜损和效率进行了测量。.本项目以提高电机能效水平为出发点，针对目前变频器驱动系统能效计量检测方法的不足，对考虑谐波的异步电机能效检测方法进行了理论研究，同时进行了一系列的相关实验。实验结果表明，本项目提出的能效检测新方法具有一定的科学意义。