Control Methods for Long-Primary Synchronous Linear Motors without mechanical velocity- or position-sensors

电动机驱动要求移动位置是一个已知的变量，以便控制它们。这个变量可以通过位置传感器直接确定，也可以通过测量定子的电压和电流间接确定。由于位置传感器价格昂贵，降低了系统的可靠性，间接方法，也称为无传感器方法，是首选的方法。避免位置传感器在线性驱动中比在旋转驱动中更重要，因为不像旋转驱动只需要一个传感器单元连接到转子轴上，在线性驱动中传感器沿着整个轨道分布，变得更加复杂，更昂贵，更不可靠。即使无传感器方法的研究通常集中在旋转电机上，同样的基本原理也可以用于线性电机。然而，在长一次电机的情况下，必须克服额外的困难，例如：用于跟踪位置的位置相关电感是非周期性的，并且由于只有一小部分定子被电机覆盖而非常小。定子端部效应引起的互感会干扰位置检测。在多段配置的电动机中，必须在分段过渡时连续确定其位置。提出研究同步长一次直线电机在无传感器位置检测中的特性、限制和机遇。在此基础上，将开发并测试一种零速度下的位置检测方法。即使关注长初级直线电机，对一般无传感器领域的贡献也是值得期待的。

Electrical motor drives require the mover position to be a known variable in order to control them. This variable can be determined directly by means of position sensors or indirectly by measuring the stator’s voltages and currents. As position sensors are expensive and reduce the system’s reliability, the indirect methods, also known as sensorless methods, are preferred.Avoiding position sensors is more significant in linear drives than in rotative ones, because unlike rotative drives that require only one sensor unit attached to the rotor shaft, in linear drives the sensor is spread along the whole track, becoming even more complex, more expensive and less reliable. Even when the research in sensorless methods has been usually focused on rotative motors, the same fundamentals can also be used for linear ones. However, in the case of long-primary motors, additional difficulties must be overcame, e.g.: The position-dependent inductance, used to track the position, is non-periodic and very small due to the fact that only a fraction of the stator is covered by the mover. Mutual inductance due to the end-effect of the stator will interfere with the position detection. In motors arranged in multiple segments, the position must be continuously determined on the segment-transitions. It is proposed to research the characteristics, constrains and opportunities of synchronous longprimary linear motors in relation to sensorless position detection. Based on them, a method to detect position down to zero speed will be developed and tested. Even when focusing on the long-primary linear motor, contributions to the sensorless field in general are also expected.