Sensorless Control of Permanent Magnet Synchronous Machines based on oversampling, FPGA based aquisition of measured currents - II

在前期的研究中，我们发现并研究了一种无编码器、高动态的永磁同步电机在低速范围(包括静止)的位置和速度估计方法，该方法在速度控制闭环系统中具有很高的位置估计精度，并且能够以高度动态的方式补偿负载扭矩的变化。这只需要电机的电感矩阵。与现有的大多数方法相比，新方法还可以进行解析参数化，并且不需要很大的计算工作量。其基础是以大约的速率对测量的电流进行过采样。106/S，可精确分析脉宽调制周期内的电流波形。由此，可以确定电流的梯度，从而可以确定磁通的变化率，并根据施加的电压将其与期望值进行比较。根据解析上可用的误差函数，可以根据所需变量确定梯度，并且只需很少的工作即可在线计算。以梯度下降的方式在线优化误差函数，在采样时间内得到期望的转子位置和速度。然而，到目前为止，这种新的方法只能在具有表面磁铁和近乎线性行为的小型机器上进行研究。在后续项目中，将寻求扩展到严重饱和的机器，例如通常用于更高功率水平的机器，例如在牵引领域。在这样的机器中，饱和效应导致各向异性消失或反转的工作范围。在我们自己的准备工作中，所开发的程序表明，当模型中包括互感时，能够在这些区域内运行的潜力。因此，在后续项目中，应将开发的程序扩展到带有埋地磁铁的更高功率的机器上使用，包括在各向异性消失或反向的区域进行操作。还必须解决副作用，如涡流效应或长电机电缆造成的电流扭曲。对于工业驱动中的应用，电流相关的电感矩阵也应该能够完全自动确定，并且不需要位置传感器。最后，应根据研究状况，将所产生的程序与其他程序进行系统比较，以便将其归入现有的知识体系。

In the previous project, an encoderless, highly dynamic position and speed estimation for PMSM in the lower speed range including standstill was found and investigated, which allows a very good accuracy of the position estimation in the closed speed control loop and can also compensate for load torque changes in a highly dynamic manner. Only the inductance matrix of the machine is required for this. In contrast to most existing methods, the new method can also be parameterized analytically and does not require a large computational effort. The basis is an oversampling of the measured currents at a rate of approx. 106/s, which allows a precise analysis of the current waveforms over the duration of a PWM period. From this, the gradients of the currents, and thus the rate of change in flux, can be determined and compared with expected values based on the applied voltages. From the analytically available error function, a gradient can be determined according to the desired variable and calculated online with little effort. An online optimization of the error function in the manner of a gradient descent leads to the desired rotor position and speed within a sampling time. So far, however, this new approach could only be investigated with a small machine with surface magnets and almost linear behavior. In the follow-up project, an extension to heavily saturating machines is pursued, such as those typically used for higher power levels, e.g. in the field of traction. In such machines, saturation effects lead to operating ranges with vanishing or reversing anisotropies. In our own preparatory work, the procedure developed shows the potential of being able to operate within these areas when the mutual inductances are included in the models. Therefore, in the follow-up project, the developed procedure shall be extended for use with a higher-power machine with buried magnets, including operation in the regions with vanishing or reversed anisotropy. Side effects, such as currents distorted by eddy current effects or by long motor cables, must also be addressed. For an application in industrial drives, the current-dependent inductance matrix should also be able to be determined fully automatically and without a position sensor. Finally, the resulting procedure should be compared systematically with other processes according to the state of research in order to classify it in the existing body of knowledge.